Éditeur(s) : HAL CCSD
Résumé : The genus Cecropia includes pioneer trees that colonize canopy gaps and cleared areas. It is widely distributed from Mexico to Northern Argentina. Cecropia trees have architecture, which corresponds to the Rauh’s architectural model. In recent studies we have found that C. obtusa/ and C. sciadophylla, in French Guiana, have a strong annual periodicity for growth, branching and flowering processes, with annual emission of 35 nodes for C. obtusa and 25 for C. sciadophylla. Those species show different life histories since C. sciadophylla has longer life expectancy. In addition, C. sciadophylla is found more frequently in forest gaps, although in French Guiana mixed populations are found. The aim of this work was to compare developmental strategies of both species in three different field stations in French Guiana and to determine how these two species coexist during its first years of life. We studied a 20-year old population of /C. sciadophylla/ at Saint Elie’s Road, a 10-year old population of /C. obtusa/ at Paracou’s field station, and a 7-year old mixed population at Counami’s Road. /C. sciadophylla /emits 25 nodes per year in both studied populations, while/ C. obtusa /emits 35 nodes in the monospecific population and 30 nodes in the mixed population. In the monocaule stage, the lower number of nodes emitted by /C. sciadophylla/ compared to /C. obtusa /is compensated with a higher internodal length, which allows finding individuals with similar ages and lengths, but different number of nodes. The branching and flowering processes start on average three years before in /C. obtusa/, however for 12-year old individuals we observed a dominancy of C. sciadophylla over C. obtusa. In the mixed population it is likely that the different life histories would decrease competition effects allowing coexistence of both species during the first stages of life
Botany 2008
Vancouver, Canada

hal-01190209
https://hal.archives-ouvertes.fr/hal-01190209
PRODINRA : 182910

Éditeur(s) : HAL CCSD Institute of Electrical and Electronics Engineers
Résumé : International audience
The state-space modeling of partially observed dynamical systems generally requires estimates of unknown parameters. The dynamic state vector together with the static parameter vector can be considered as an augmented state vector. Classical filtering methods, such as the extended Kalman filter (EKF) and the bootstrap particle filter (PF), fail to estimate the augmented state vector. For these classical filters to handle the augmented state vector, a dynamic noise term should be artificially added to the parameter components or to the deterministic component of the dynamical system. However, this approach degrades the estimation performance of the filters. We propose a variant of the PF based on convolution kernel approximation techniques. This approach is tested on a simulated case study.
ISSN: 0018-9251

inria-00459886
https://hal.inria.fr/inria-00459886
DOI : 10.1109/TAES.2009.5259183

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
After the January 12, 2010, Haiti earthquake, we deployed a mainly offshore temporary network of seismologic stations around the damaged area. The distribution of the recorded aftershocks, together with morphotectonic observations and mainshock analysis, allow us to constrain a complex fault pattern in the area. Almost all of the aftershocks have a N‐S compressive mechanism, and not the expected left‐lateral strike‐slip mechanism. A first‐order slip model of the mainshock shows a N264°E north‐dipping plane, with a major left‐lateral component and a strong reverse component. As the aftershock distribution is sub‐parallel and close to the Enriquillo fault, we assume that although the cause of the catastrophe was not a rupture along the Enriquillo fault, this fault had an important role as a mechanical boundary. The azimuth of the focal planes of the aftershocks are parallel to the north‐dipping faults of the Transhaitian Belt, which suggests a triggering of failure on these discontinuities. In the western part, the aftershock distribution reflects the triggering of slip on similar faults, and/or, alternatively, of the south‐dipping faults, such the Trois‐Baies submarine fault. These observations are in agreement with a model of an oblique collision of an indenter of the oceanic crust of the Southern Peninsula and the sedimentary wedge of the Transhaitian Belt: the rupture occurred on a wrench fault at the rheologic boundary on top of the under‐thrusting rigid oceanic block, whereas the aftershocks were the result of the relaxation on the hanging wall along pre‐existing discontinuities in the frontal part of the Transhaitian Belt.
ISSN: 0094-8276

insu-00643489
https://hal-insu.archives-ouvertes.fr/insu-00643489
https://hal-insu.archives-ouvertes.fr/insu-00643489/document
https://hal-insu.archives-ouvertes.fr/insu-00643489/file/GRL-haiti.2011.pdf
DOI : 10.1029/2011GL049799

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Orogenic lherzolites exhibit a specific (although reproducible) platinum-group element signature characterized by slight positive deviations of Pd/Ir, Rh/Ir and Ru/Ir ratios from the canonical chondritic model. Such a signature was alternatively considered to be a compositional feature of the primitive upper mantle or resulting from sulfide melt addition by refertilisation reactions in the continental lithosphere. To shed additional light on this conundrum, the distribution of PGE in FON B 93, an unserpentinized, fertile (3.24% Al2O3) orogenic lherzolite (French Pyrenees) used as in-house standard by our group, has been studied to different scales, from the bulk rock to trace minerals. In addition to new ICPMS analyses after separation into Nis and Te coprecipitation, its whole-rock PGE concentrations were redetermined by three different laboratories using very precise ID-ICP-MS methods after digestion of the sample in Carius tube at T=250 degrees C and 320 degrees C or in high-pressure asher (HPA-S). The four methods produce reproducible Ru, Rh and Pd contents (7.1 +/- 0.18 ppb; 1.43 +/- 0.05 ppb; 7.1 +/- 0.30 ppb) whereas the non-ID NiS-fire assay method underestimates the Os and Ir concentrations by c.a. 10 and 15% compared to ID-ICP-MS analyses (4.40 +/- 0.07 and 4.00 +/- 0.17 ppb, respectively). Platinum was the most difficult to analyse. If performed on powder aliquots smaller than 3 g, the ID-ICP-MS analyses generate strong nugget effects while the non-ID NiS-fire assay method yields statistically lower (but highly reproducible) Pt concentrations (6.92 +/- 0.26 ppb). These features reflect the strong partitioning of Pt into trace phases that SEM and laser ablation-ICP-MS analyses on thin sections identify as both high-temperature Pt-Ir-Os alloys and Pt-(Pd) tellurides of likely subsolidus origin; ten to fifteen grains ranging in maximum dimension from a few micrometres to a few hundreds of nanometers, were identified by standard polished thin section. LA-ICP-MS data on base metal sulfides (25 grains analysed), coupled with the whole-rock S concentration (277 +/- 10 ppm) and modal composition of the BMS (90% pentlandite+accessory pyrite and secondary pyrrhotite + 10% chalcopyrite) allowed the contribution of the BMS phase to the PGE budget of FON B 93 to be estimated. Except Pt that exhibits a 95% deficit in the BMS phase, the PGE concentrations measured by ID-ICP-MS can be balanced by BMS while Al-spinel is a negligible contributor, accounting for less than 0.5% of the Ru budget. The occurrence of Pt in trace phases may bias the whole-rock Pt concentrations because 1) mechanical collection of Pt-rich trace phases remains problematic with the Nis button, and 2) Pt-Ir-Os alloys may be prone to digestion problems in conventional Carius tube procedures. Since they could be stable at mantle depth, such refractory alloys that contain Os and Ir may also have enhanced the heavy PGEs/light PGEs fractionation. Our observations likely pertain to orogenic lherzolites as a whole because BMS assemblages in these mantle rocks record evolution at low sulfur fugacity, which prevents Pt-Ir-Os alloy from entering the Mss in the mantle; moreover, at subsolidus temperature, pentlandite, the major BMS, cannot accommodate 0 valence state Pt.
ISSN: 0009-2541

hal-00411486
https://hal.archives-ouvertes.fr/hal-00411486
DOI : 10.1016/j.chemgeo.2007.06.030

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Molds and allergens are common indoor biocontaminants. The aims of this study were to assess the concentrations of common molds in indoor air and floor dust and the concentrations of house dust mite, cat and dog allergens in mattress dust in French dwellings, and to assess predictors of these concentrations. A sample of 150 houses in Brittany (western France) was investigated. Airborne Cladosporium and Penicillium were detected in more than 90% of the dwellings, Aspergillus in 46% and Alternaria in only 6% of the housings. Regarding floor dust samples, Cladosporium and Penicillium were detected in 92 and 80% of the housings respectively, Aspergillus in 49% and Alternaria in 14%. House dust mite allergens Der p1 and Der f1 were detected in 90% and 77% of the mattress dust samples respectively and Can f1 and Fel d1 in 37% and 89% of the homes. Airborne and dustborne mold concentrations, although not statistically correlated (except for Aspergillus) shared most of their predictors. Multivariate linear models for mold levels, explaining up to 62% of the variability, showed an influence of the season, of the age of the dwelling, of aeration habits, presence of pets, smoking, signals of dampness, temperature and relative humidity. Allergens in the dust of the mattress were strongly related to the presence of pets and cleaning practices of bedsheets, these factors accounting for 60% of the variability. This study highlights ubiquitous contamination by molds and underlines complex interaction between outdoor and indoor sources and factors
ISSN: 0048-9697

hal-01165440
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01165440
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01165440/file/Molds%20and%20allergens%20in%20French%20dwellings%20rev2_clean%20version.pdf
DOI : 10.1016/j.scitotenv.2015.06.039
PUBMED : 26094801

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
Infant and neonatal mortality indicators are known to vary geographically, possibly as a result of socioeconomic and environmental inequalities. To better understand how these factors contribute to spatial and temporal patterns, we conducted a French ecological study comparing two time periods between 2002 and 2009 for three (purposefully distinct) Metropolitan Areas (MAs) and the city of Paris, using the French census block of parental residence as the geographic unit of analysis. We identified areas of excess risk and assessed the role of neighborhood deprivation and average nitrogen dioxide concentrations using generalized additive models to generate maps smoothed on longitude and latitude. Comparison of the two time periods indicated that statistically significant areas of elevated infant and neonatal mortality shifted northwards for the city of Paris, are present only in the earlier time period for Lille MA, only in the later time period for Lyon MA, and decrease over time for Marseille MA. These city-specific geographic patterns in neonatal and infant mortality are largely explained by socioeconomic and environmental inequalities. Spatial analysis can be a useful tool for understanding how risk factors contribute to disparities in health outcomes ranging from infant mortality to infectious disease-a leading cause of infant mortality.
ISSN: 1660-4601

hal-01359563
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01359563
DOI : 10.3390/ijerph13060624
PUBMED : 27338439

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The aim of this study is to assess the availability and quality of data from the International GNSS Service (IGS) Global Positioning System (GPS) network in Africa, especially for retrieving zenith tropospheric delay (ZTD), from which precipitable water vapour (PWV) can be derived, in view of application to the African Monsoon Multidisciplinary Analysis (AMMA) project. Three major error sources for the GPS data analysis evaluating PWV in Africa are the accuracy of the satellite orbits, the correction for the radio delay induced by the ionosphere and the vertical site displacements due to ocean loading. The first part of this study examines these error sources and the validity of GPS data for meteorological applications in Africa in dedicated analyses spanning the year 2001. These analyses were performed using the IGS precise orbits. Weak degradation of baseline precision with increasing baseline lengths suggests that the average orbital error is not limiting the GPS analysis in Africa. The impact of the ionosphere has been evaluated during a maximum of solar activity in 2001. The loss of L2 data has actually been observed. It amounts to 2% on average for 2001, with maxima of 8% during magnetic storm events. A slight decrease in formal accuracy of ZTD seems to be related to the loss of L2 data at the end of the day. This indicates that scintillation effects are present in the GPS observations but however are not a major limitation. The impact of ocean loading is found to be significant on ZTD estimates (up to ±2 mm in equivalent PWV). The use of a proper ocean loading model eliminates this effect. The second aspect of this study concerns the IGS analysis quality for the African stations. The accuracy has been assessed through position dispersion between individual solutions and the most recent version of the IGS combined solution IGb00, and residuals from the transformation of the IGS combined solution into the International Terrestrial Reference Frame 2005. The positioning performance of the IGS analysis is consistent with an accuracy in ZTD of ±6 mm (±1 mm in PWV), as requested for meteorological applications such as planned in AMMA.
ISSN: 1364-6826

insu-00347961
https://hal-insu.archives-ouvertes.fr/insu-00347961
DOI : 10.1016/j.jastp.2007.04.008

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
New petrographic and microstructural observations, mineral equilibria modelling and U/Pb (monazite) geochronological studies were carried out to investigate the relationships between deformation and metamorphism across the Rehamna massif (Moroccan Variscan belt). In this area, typical Barrovian (muscovite to staurolite) zones developed in Cambrian to Carboniferous metasedimentary rocks that are distributed around a dome-like structure. First assemblages are characterized by the presence of locally preserved andalusite, followed by prograde evolution culminating at 6 kbar and 620 °C in the structurally deepest staurolite zone rocks. This Barrovian sequence was subsequently uplifted to supracrustal levels, heterogeneously reworked at greenschist facies conditions, which was followed locally by static growth of andalusite, indicating heating to 2.5–4 kbar and 530–570 °C. The 206Pb/238U monazite age of 298.3 ± 4.1 Ma is interpreted as minimum age of peak metamorphic conditions, whereas the ages of 275.8 ± 1.7 Ma and 277.0 ± 1.1 Ma date decompression and heating at low pressure, in agreement with previous dating of Permian granitoids intruding the Rehamna massif. The prograde metamorphism occurred during thickening and associated horizontal flow in the deeper crust (S1 horizontal schistosity). The horizontally disposed metamorphic zones were subsequently uplifted by a regional scale antiform during ongoing N–S compression. The re-heating of the massif follows late massive E–W shortening, refolding and retrograde shearing of all previous fabrics coevally with regionally important intrusions of Permian granitoids. We argue that metamorphic evolution of the Rehamna massif occurred several hundred kilometres from the convergent plate boundaries in the interior of continental Gondwanan plate. The tectonometamorphic history of the Rehamna massif is put into Palaeozoic plate tectonic perspective and Late Carboniferous reactivation of (Devonian)–Early Carboniferous basins formed during stretching of the north Gondwana margin and formation of the Palaeotethys Ocean. The inherited heat budget of these magma-rich basins plays a role in the preferential location of this intracontinental orogen. It is shown that rapid transition from lithospheric stretching to compression is characterized by specific HT type of Barrovian metamorphism, which markedly differs from similar Barrovian sequences along Palaeozoic plate boundaries reported from Variscan Europe.
ISSN: 0263-4929

hal-01468009
https://hal.archives-ouvertes.fr/hal-01468009
DOI : 10.1111/jmg.12214

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
BACKGROUND: The use of pesticides and the related environmental contaminations can lead to human exposure to various molecules. In early-life, such exposures could be responsible for adverse developmental effects. However, human health risks associated with exposure to complex mixtures are currently under-explored. OBJECTIVE: THIS PROJECT AIMS AT ANSWERING THE FOLLOWING QUESTIONS: What is the influence of exposures to multiple pesticides on the metabolome? What mechanistic pathways could be involved in the metabolic changes observed? METHODS: Based on the PELAGIE cohort (Brittany, France), 83 pregnant women who provided a urine sample in early pregnancy, were classified in 3 groups according to the surface of land dedicated to agricultural cereal activities in their town of residence. Nuclear magnetic resonance-based metabolomics analyses were performed on urine samples. Partial Least Squares Regression-Discriminant Analysis (PLS-DA) and polytomous regressions were used to separate the urinary metabolic profiles from the 3 exposure groups after adjusting for potential confounders. RESULTS: The 3 groups of exposure were correctly separated with a PLS-DA model after implementing an orthogonal signal correction with pareto standardizations (R2 = 90.7% and Q2 = 0.53). After adjusting for maternal age, parity, body mass index and smoking habits, the most statistically significant changes were observed for glycine, threonine, lactate and glycerophosphocholine (upward trend), and for citrate (downward trend). CONCLUSION: This work suggests that an exposure to complex pesticide mixtures induces modifications of metabolic fingerprints. It can be hypothesized from identified discriminating metabolites that the pesticide mixtures could increase oxidative stress and disturb energy metabolism.
ISSN: 1932-6203

inserm-00863407
http://www.hal.inserm.fr/inserm-00863407
http://www.hal.inserm.fr/inserm-00863407/document
http://www.hal.inserm.fr/inserm-00863407/file/journal.pone.0064433.pdf
PUBMED : 23704985

Éditeur(s) : HAL CCSD BMJ Publishing Group
Résumé : International audience
OBJECTIVE: To investigate the role of occupational exposure to chlorinated solvents in lung cancer aetiology. METHODS: ICARE (Investigation of occupational and environmental CAuses of REspiratory cancers) is a French, multicentre, population-based, case-control study. Information on the lifelong work history of 2926 cases and 3555 controls was collected using standardised questionnaires. Occupational exposures were assessed using job-exposure matrices for five chlorinated solvents. Solvents were studied separately and in combinations. ORs were computed using unconditional logistic regression models adjusted for classic risk factors, including a history of cigarette smoking and exposure to asbestos. Adjustment for socioeconomic status (SES) was also made. RESULTS: After adjustment for exposure to asbestos, we observed a positive, statistically significant association with lung cancer for men and women exposed to a combination of perchloroethylene (PCE), trichloroethylene and dichloromethane (DCM). Further adjustment for SES slightly decreased this association. In contrast, no statistically significant associations were found for other solvent combinations. CONCLUSIONS: These results suggest that exposure to PCE may constitute a risk factor for lung cancer, especially among women, who seem to have a higher prevalence of exposure than men.
ISSN: 1351-0711

hal-01063908
https://hal.archives-ouvertes.fr/hal-01063908
DOI : 10.1136/oemed-2014-102182
PUBMED : 25015929

Éditeur(s) : HAL CCSD EDP Sciences
Résumé : Cette communication présente les principaux résultats du projet ExtraFlo sur l'estimation des pluies et crues extrêmes. A partir d'un jeu de données conséquent de plusieurs milliers de stations, une procédure d'inter-comparaison a permis d'évaluer les performances d'une trentaine d'implémentations différentes issues de différentes combinaisons (modèle probabiliste, méthode d'estimation, cadre local / régional / mixte local et régional). Le projet ExtraFlo a permis de mettre en évidence le manque de robustesse des approches basées sur le traitement statistique d'une série de quelques dizaines d'années d'observation. Des alternatives intéressantes existent, basées sur l'exploitation des records de pluie et de débit à l'échelle d'une région, de la collecte de données historiques quand cela est possible, de méthodes de simulation basées sur le couplage d'un générateur d'averses avec un modèle hydrologique pour la transformation des pluies en débit, ou des traces morphologiques laissées par les crues anciennes.
ISSN: 0018-6368

hal-01054313
https://hal.archives-ouvertes.fr/hal-01054313
DOI : 10.1051/1hb/2014010

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Resolving the early diversification of animal lineages has proven difficult, even using genome-scale datasets. Several phylogenomic studies have supported the classical scenario in which sponges (Porifera) are the sister group to all other animals (''Porifera-sister''3 hypothesis), consistent with a single origin of the gut, nerve cells, and muscle cells in the stem lineage of eumetazoans (bilaterians + ctenophores + cnidarians). In contrast, several other studies have recovered an alternative topology in which ctenophores are the sister group to all other animals (including sponges). The ``Ctenophora-sister'' hypothesis implies that eumetazoan-specific traits, such as neurons and muscle cells, either evolved once along the metazoan stem lineage and were then lost in sponges and placozoans or evolved at least twice independently in Ctenophora and in Cnidaria + Bilateria. Here, we report on our reconstruction of deep metazoan relationships using a 1,719-gene dataset with dense taxonomic sampling of non-bilaterian animals that was assembled using a semi-automated procedure, designed to reduce known error sources. Our dataset outperforms previous metazoan gene superalignments in terms of data quality and quantity. Analyses with a best-fitting site-heterogeneous evolutionary model provide strong statistical support for placing sponges as the sister-group to all other metazoans, with ctenophores emerging as the second-earliest branching animal lineage. Only those methodological settings that exacerbated long-branch attraction artifacts yielded Ctenophora-sister. These results show that methodological issues must be carefully addressed to tackle difficult phylogenetic questions and pave the road to a better understanding of how fundamental features of animal body plans have emerged.
ISSN: 0960-9822

hal-01681528
https://hal.archives-ouvertes.fr/hal-01681528
DOI : 10.1016/j.cub.2017.02.031

Éditeur(s) : HAL CCSD AGU and the Geochemical Society
Résumé : International audience
Analysis of short-term deformation along the southern part of Dead Sea Fault (DSF) provides a systematic view of kinematics this part of the continental transform. The southern DSF consists of two principal segments: the Wadi Araba and Jordan Valley faults. In addition to other regional continuous GPS data, this study uses new data from 25 survey sites and 4 continuous GPS stations in Jordan for improved near-field observations. Resulting velocities are reported with 1-sigma uncertainties ranging from 0.4-1.0 mm/yr. Application of elastic dislocation models yields estimates of slip rates for Wadi Araba and Jordan Valley faults are 4.9 +/- 0.4 mm/yr and 4.7 +/- 0.4 mm/yr, respectively. Modeling also suggests different depths of effective fault locking with 15 +/- 5 km and 8 +/- 5 km for the Wadi Araba and Jordan Valley faults, respectively. These slip rates are generally consistent with the upper end of the range of slip rates estimated from late Quaternary geology. Spatial variations in effective fault locking generally correspond with a heterogeneous mantle lithosphere. A similar observation can be observed along the southern San Andreas Fault, and this may reflect the influence of heterogeneity in the uppermost mantle on crustal faulting processes.
ISSN: 1525-2027

hal-00689031
https://hal.archives-ouvertes.fr/hal-00689031
DOI : 10.1029/2011GC003736

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
To improve earthquake location, we create a 3-D a priori P-wave velocity model (3-DVM) that approximates the large velocity variations of the Ecuadorian subduction system. The 3-DVM is constructed from the integration of geophysical and geological data that depend on the structural geometry and velocity properties of the crust and the upper mantle. In addition, specific station selection is carried out to compensate for the high station density on the Andean Chain. 3-D synthetic experiments are then designed to evaluate the network capacity to recover the event position using only P arrivals and the MAXI technique. Three synthetic earthquake location experiments are proposed: (1) noise-free and (2) noisy arrivals used in the 3-DVM, and (3) noise-free arrivals used in a 1-DVM. Synthetic results indicate that, under the best conditions (exact arrival data set and 3-DVM), the spatiotemporal configuration of the Ecuadorian network can accurately locate 70 per cent of events in the frontal part of the subduction zone (average azimuthal gap is 289° ± 44°). Noisy P arrivals (up to ± 0.3 s) can accurately located 50 per cent of earthquakes. Processing earthquake location within a 1-DVM almost never allows accurate hypocentre position for offshore earthquakes (15 per cent), which highlights the role of using a 3-DVM in subduction zone. For the application to real data, the seismicity distribution from the 3-D-MAXI catalogue is also compared to the determinations obtained in a 1-D-layered VM. In addition to good-quality location uncertainties, the clustering and the depth distribution confirm the 3-D-MAXI catalogue reliability. The pattern of the seismicity distribution (a 13 yr record during the inter-seismic period of the seismic cycle) is compared to the pattern of rupture zone and asperity of the Mw = 7.9 1942 and the Mw = 7.7 1958 events (the Mw = 8.8 1906 asperity patch is not defined). We observe that the nucleation of 1942, 1958 and 1906 events coincides with areas of positive Simple Bouguer anomalies and areas where marine terraces are still preserved on the coastal morphology. From north to south: (1) the 1958 rupture zone is almost aseismic and is attributed to a zone of high coupling; (2) south of the Galera alignment (perpendicular to the trench), the 1942 rupture zone presents moderate seismicity, deeper on the seismogenic interplate zone, and abutting on the Jama cluster (to the south). This cluster is facing the Cabo Pasado cap and positive Bouguer anomalies on the overriding margin. We suspect that this cluster reflects a zone of local asperity (partial coupling). South of the Jama cluster, the spherical aseismic zone in the Bahia area is interpreted as having a low seismic coupling (steady creep motion or slow slip events). We suspect that the site that generated the three M > 7 events (1896, 1956 and 1998) correspond to a small patch of strong coupling. To the south, in the Manta-Puerto Lopez zone, the seismicity is mainly organized in earthquake swarms (1998, 2002, 2005). Although slow slip events have been observed in the area (Vallée et al. submitted), we infer from the coastline shape, the marine terraces and the high positive Bouguer anomalies that the seismicity here might reveal a significant amount of seismic coupling.
ISSN: 0956-540X

hal-00873478
https://hal.archives-ouvertes.fr/hal-00873478
DOI : 10.1093/gji/ggs083

Éditeur(s) : HAL CCSD
Résumé : Mes travaux de recherche portent sur la caractérisation de l’hétérogénéité, précisément des structures spatiales et de la diversité. J’ai développé de nouvelles mesures de la structure spatiale appliquées principalement en économie géographique et des mesures de diversité appliquées principalement à la biodiversité des arbres. Le fil directeur de ces travaux méthodologiques est de construire des mesures correspondant à une réalité physique, facilement compréhensible, pouvant être utilisées ensuite pour comprendre sans ambiguïté les processus économiques ou écologiques concernés.Mon projet de recherche à moyen terme consiste à combiner les deux approches pour caractériser la diversité explicitement dans l’espace et dans le temps, et à étendre mes méthodes à d’autres objets (diversité microbienne par exemple) plus complexes. Au-delà de ces travaux méthodologiques, mon objectif à plus long terme est d’aller vers la modélisation des processus générant les patrons de diversité.
https://hal-agroparistech.archives-ouvertes.fr/tel-01502970

tel-01502970
https://hal-agroparistech.archives-ouvertes.fr/tel-01502970
https://hal-agroparistech.archives-ouvertes.fr/tel-01502970/document
https://hal-agroparistech.archives-ouvertes.fr/tel-01502970/file/HDR%20-%20Marcon%20-%202016.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
BACKGROUND: Numerous studies have linked prenatal traffic-related air pollution exposure to fetal growth. Recently, several studies have suggested exploring this association independently among boys and girls because of potential sex-specific biological vulnerability to air pollution. Residence-based factors can also influence fetal growth by enhancing susceptibility to the toxic effects of air pollution and must also be considered in these relations. OBJECTIVE: We examined sex-specific associations between prenatal air pollution exposure and fetal growth and explored whether they differed by the urban-rural status of maternal residence. METHODS: This study relied on the PELAGIE mother-child cohort (2521 women, Brittany, France, 2002-2006). Fetal growth was assessed through birth weight, head circumference and small weight (SGA) and small head circumference (SHC) for gestational age. Nitrogen dioxide (NO2) concentrations at mothers' homes were estimated by using a land use regression model taking into account temporal variation during pregnancy. Associations between estimated NO2 concentrations and fetal growth were assessed with linear regression or logistic regression models, depending on the outcome investigated. RESULTS: An interquartile range (8.8µgm(-3)) increase in NO2 exposure estimates was associated with a 27.4g (95% CI 0.8 to 55.6) increase in birth weight and a 0.09cm (95% CI 0.00-0.17) significant increase in head circumference, among newborn boys only. Their risks of SGA and SHC were reduced (OR 0.70, 95% CI 0.53-0.92, OR 0.76, 95% CI 0.56-1.03, respectively, for an increase of 8.8µgm(-3)). No statistically significant trends were observed among girls. Urban-rural status modified the effect of air pollution only for SHC and again only for newborn boys. CONCLUSION: Findings from this study confirm the need to consider sex-specific associations between air pollution and fetal growth and to investigate possible mechanisms by which traffic-related air pollution may increase anthropometric parameters at birth
Environmental Research

hal-01205354
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01205354
DOI : 10.1016/j.envres.2015.09.006
PUBMED : 26378737

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Whereas it is well established that prenatal exposure to polychlorinated biphenyls (PCBs) can disrupt children's behavior, early postnatal exposure has received relatively little attention in environmental epidemiology. To evaluate prenatal and postnatal exposures to PCB-153, a proxy of total PCB exposure, and their relation to inattention and activity in 5-year-old Inuits from the Cord Blood Monitoring Program. Prenatal exposure to PCBs was informed by cord plasma PCB-153 levels. We used a validated pharmacokinetic model to estimate monthly infants' levels across the first year of life. Inattention and activity were assessed by coding of video recordings of children undergoing fine motor testing. We used multivariable linear regression to evaluate the association between prenatal and postnatal PCB-153 levels and inattention (n=97) and activity (n=98) at 5years of age. Cord plasma PCB-153 was not associated with inattention and activity. Each interquartile range (IQR) increase in estimated infant PCB-153 levels at 2months was associated with a 1.02% increase in the duration of inattention (95% CI: 0.04, 2.00). Statistical adjustment for the duration of breastfeeding slightly increased regression coefficients for postnatal level estimates, some of which became statistically significant for inattention (months: 2-4) and activity (months: 2-5). Our study adds to the growing evidence of postnatal windows of development during which children are more susceptible to neurotoxicants like PCBs.
ISSN: 0160-4120

hal-01134338
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134338
DOI : 10.1016/j.envint.2015.02.004
PUBMED : 25796081

Éditeur(s) : HAL CCSD AGU and the Geochemical Society
Résumé : International audience
The 2004 Aceh and 2005 Nias events are the two greatest earthquakes of the past 40 years with a total rupture of 1700 km long and a coseismic slip reaching up to 25 m. These two earthquakes have caused large stress perturbations which significantly altered seismic activity in the Sumatra-Andaman region. Using both detailed mapping of failure planes and various slip distributions, we calculate this stress change along the Sumatra-Andaman-Sagaing fault system from central Sumatra to southern Myanmar. The static Coulomb stress change Delta CFF and the observed seismic activity are in very good agreement with a Coulomb index similar to 20% greater than the one obtained for random events. Compared to previous studies, this high Coulomb Index confirms two important issues on the use of static stress change criterion: unsuited to study near-field aftershocks and only relevant for aftershocks analysis on large and mature faults at a time scale of several months. The calculated Delta CFF distribution suggests that the 2004 and 2005 earthquakes inhibit failure on the North Andaman rift and on the Sagaing fault, while failure is encouraged along the transform Andaman zone, the central Andaman rift, the West Andaman fault, the Sumatra fault system, and the offshore thrust faults west of Sumatra Island. The maximum value of similar to 15-20 bar (1.5-2 MPa) for Delta CFF is reached in the northern part of the Sumatra fault system. This high value together with the lack of major earthquake in the last 170 years result in a high seismic hazard for this region. Our results are also consistent with temporal evolution of both earthquakes' location and focal mechanism prior to and after the events. In particular, we explain the occurrence and the mechanism of seismic swarms observed in the central Andaman rift and along the west Andaman fault. Finally, our calculations reveal that the seismicity in the Andaman rift zone can only be explained if mu' > 0.5. This result leads to two end-member models: one with a constant and high fault friction and one with spatial variations, for which friction may depend on either the nature of the lithosphere (oceanic versus continental) or the fault type.
ISSN: 1525-2027

hal-00456027
https://hal.archives-ouvertes.fr/hal-00456027
DOI : 10.1029/2008GC002167

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The anisotropy of vibrational properties influences the acoustic behaviour of wooden pieces and their dependence on grain angle (GA). As most pieces of wood include some GA, either for technological reasons or due to grain deviations inside trunks, predicting its repercussions would be useful. This paper aims at evaluating the variability in the anisotropy of wood vibrational properties and analysing resulting trends as a function of orientation. GA dependence is described by a model based on transformation formulas applied to complex compliances, and literature data on anisotropic vibrational properties are reviewed. Ranges of variability, as well as representative sets of viscoelastic anisotropic parameters, are defined for mean hardwoods and softwoods and for contrasted wood types. GA-dependence calculations are in close agreement with published experimental results and allow comparing the sensitivity of different woods to GA. Calculated trends in damping coefficient (tanδ) and in specific modulus of elasticity (E′/ρ) allow reconstructing the general tanδ-E′/ρ statistical relationships previously reported. Trends for woods with different mechanical parameters merge into a single curve if anisotropic ratios (both elastic and of damping) are correlated between them, and with axial properties, as is indicated by the collected data. On the other hand, varying damping coefficient independently results in parallel curves, which coincide with observations on chemically modified woods, either "artificially", or by natural extractives.
ISSN: 0043-7719

hal-00804242
https://hal.archives-ouvertes.fr/hal-00804242
https://hal.archives-ouvertes.fr/hal-00804242/document
https://hal.archives-ouvertes.fr/hal-00804242/file/Anisotropy_wood_variational_properties_Bremaud_al_2011.pdf
DOI : 10.1007/s00226-010-0393-8

Éditeur(s) : HAL CCSD
Résumé : The presence of obstacles met in natural environment by the flow, influences the dispersion of air pollutants which it carries. This thesis, based on spatiotemporal micro-meteorological measurements in tropical region, aims at studying the dispersion of compounds emitted by the ecosystem mangrove according to the weather conditions. At a daily scale, the meteorological analysis reveals, besides the presence of Trade Winds, the existence of thermal flows of which nocturnal thermodynamic parameters have been defined. The field observation has shown that the weak intensity of the wind disadvantages the dispersion of compounds emitted during the night. At a finer scale, the existence of a spectral gap separating large scale phenomena of those related to turbulence has been demonstrated. These last ones were treated by spectral and statistical approaches to quantify the turbulent fluxes of momentum and sensible heat during the night, for an averaged duration of 13 minutes. The stratification of the surface layer has been considered and determined by Monin-Obukhov similarity theory. The measurements acquired at night and the application of Kolmogorov theory allowed us to deduct the dissipation rate of energy and the size of the vortices at 5.5 meters in height. This work has also led us, by gas chromatography coupled to mass spectrometry, to identify, in mangrove, sulphurated volatil organic compounds, organohalogen, BTEX, ... All these results will later serve to feed dispersion models related to the studied ecosystem.
La présence d'obstacles rencontrés en milieu naturel par l'écoulement, influence la dispersion des polluants qu'il transporte. Cette thèse, fondée sur des mesures micro-météorologiques spatio-temporelles en région tropicale, vise à étudier la dispersion de composés émis par l'écosystème mangrove en fonction des conditions météorologiques. A l'échelle journalière, l'analyse météorologique révèle, outre la présence des Alizés, l'existence d'écoulements thermiques dont des paramètres thermodynamiques nocturnes ont été définis. L'observation terrain nous a montré que la faible intensité du vent défavorise la dispersion des composés émis durant la nuit. A une échelle plus fine, l'existence d'un trou spectral séparant les phénomènes de grande échelle de ceux liés à la turbulence a été mise en évidence. Ces derniers ont été traités par des approches spectrale et statistique pour quantifier les flux turbulents de quantité de mouvement et de chaleur sensible, pendant la nuit, pour une durée de moyenne de l'ordre de 13 minutes. L'état de stratification de la couche de surface a été pris en compte et déterminé par la théorie de similitude de Monin-Obukhov. Les mesures nocturnes effectuées et l'application de la théorie de Kolmogorov ont permis de déduire les taux de dissipation de l'énergie et la taille des tourbillons à 5,5 m d'altitude. Ce travail a également conduit, par l'analyse chromatographique en phase gazeuse couplée à la spectrométrie de masse, à l'identification, en mangrove, de composés organiques volatils soufrés, des organohalogénés, des BTEX, ... L'ensemble de ces résultats servira ultérieurement à alimenter les modèles de dispersion spécifiques liés aux écosystèmes étudiés.
https://tel.archives-ouvertes.fr/tel-00665882

Droits : info:eu-repo/semantics/OpenAccess
NNT : 11AGUY0438
tel-00665882
https://tel.archives-ouvertes.fr/tel-00665882
https://tel.archives-ouvertes.fr/tel-00665882/document
https://tel.archives-ouvertes.fr/tel-00665882/file/ThA_seCdAlexis.pdf