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Publications 2008

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[hal-01521015] Holocene history of the River Seine, Paris, France : bio-chronostratigraphic and geomorphological evidence from the Quai-Branly

18 mai 2017

Bio-chronostratigraphic observations compiled from Quai-Branly in Paris (France) and their comparison with previous studies in the Paris Basin allow documentation of the morphodynamic evolution of the River Seine during the middle and late Holocene. This history begins in the Boreal (between 9500 and 8850 cal. BP), with the deposition of tufa, expressing a stabilized river bed. During the second part of the sub-Boreal the water-table was low. At the beginning of the sub-Atlantic (towards 2800/2700 cal. BP), alluvial dynamics increase, as is recorded elsewhere throughout the Paris Basin. At the beginning of the second part of the sub- Atlantic (around 2000 cal. BP), flood dynamics persisted at a lower intensity. Human occupation occurred from the fifth century AD. Before or around the beginning of the seventeenth century AD, a natural levee was built, indicating the progressive attachment of the Quai-Branly area to the floodplain. The hydrodynamic evolution of the River Seine observed at the Quai-Branly site is similar to that recorded in other river valley floors of the Paris Basin. This evolution appears to be in response to global climatic changes rather than to variations induced by human activities.

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[hal-01302028] Introduction

13 avril 2016

Lors du 131e congrès du CTHS qui s'est tenu à Grenoble au printemps 2006, la section de Pré et Protohistoire, à laquelle se sont associés quelques antiquisants, a privilégié une actualité archéologique de la montagne alpine et de ses marges. Le volume issu de ces travaux regroupe 19 contributions couvrant l'ensemble des sujets qui permettent d'aborder la longue histoire de la colonisation des Alpes. La spécificité et la variété des milieux naturels présents sont abordées par plusieurs articles pour le Paléolithique, le Néolithique, l'âge du Bronze et parfois jusqu'à l'Antiquité. L'exploitation des très nombreuses ressources, notamment lithiques et métallurgiques, constitue un attrait important de cette montagne et un maillon fort dans la caractérisation des processus d'innovation. L'exploitation et la gestion d'autres ressources comme le sel ou le bétail soulignent l'importance du cadre économique alpin et ses relations avec les groupes humains périphériques. Ce volume aborde également la matérialisation locale des cultures et la variation temporelle des communautés. Enfin, les lecteurs passionnés par les Alpes découvriront toute la profondeur historique de l'évolution complexe du peuplement de cette montagne.

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[tel-00403128] Impacts sédimentaires de la présence humaine et des variations climatiques. Exemples d’enregistrements lacustres, fluviatiles et estuariens.

17 décembre 2015

Ce mémoire d'HDR est établi comme « un état des lieux » de mes travaux de recherche autour du thème « sédimentation continentale », et une présentation de mes perspectives de recherche. Il présente un bilan des travaux de recherche réalisés depuis la période post-doctorale. La question centrale est la suivante : quelle est la part relative du climat et de la pression anthropique dans l'érosion du domaine continental ? Le Quaternaire est caractérisé par une oscillation rapide du climat entre des périodes glaciaires et interglaciaires. Depuis peu, l'étude des variations naturelles du climat, particulièrement celui de la période interglaciaire dans laquelle nous vivons, l'Holocène, a connu un regain d'intérêt avec la mise en évidence d'un réchauffement global de la planète dont l'origine est, au moins en partie, anthropique. Afin de pouvoir cerner et modéliser l'impact réel de l'Homme sur le climat, il est indispensable de connaître avec précision les paramètres forçant les variations climatiques naturelles et les effets de ces variations sur l'environnement, et en particulier les enregistrements sédimentaires puisque ceux-ci sont utilisés dans les reconstructions climatiques puis les modélisations du climat. Les bassins versants, de tailles variées, et l'échelle de temps étudiés permettent de suivre à très court, court et moyen terme uniquement l'effet du climat puis la mise en place de la pression anthropique et son impact dans différents contextes sédimentaires. Les lochs, lacs et tourbières sont des sites dans lesquels les enregistrements sédimentaires sont généralement continus depuis le dernier maximum glaciaire (environ 20 000 ans) et souvent caractérisés par une résolution très fine. En revanche, les enregistrements sédimentaires en domaine alluvial et estuarien sont très réduits et fragmentés, mais non dénués d'intérêt. Il s'agit donc nécessairement de conduire une approche pluridisciplinaire. Au sein de cette thématique globale, mes activités de recherche sont centrées sur une approche minéralogique, granulométrique et géochimique de l'impact des variations climatiques et des phases d'anthropisation sur les sédiments. La question de la datation des sédiments est alors cruciale pour corréler entre eux des événements d'impact régional. C'est là qu'intervient la mise en évidence et la caractérisation de niveaux de téphras dont la dispersion régionale est instantanée à l'échelle des temps géologiques.

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[hal-01138022] Entre forme d’habitat groupé et forme d’habitat dispersé : le cas intermédiaire d’une occupation rurale aux IIIe-IVe siècles ap. J.C entre Fragnes et Virey-le-Grand (Saône et Loire).

1er avril 2015

Un diagnostic réalisé en 2008 sur une emprise de 98 ha, au nord-est de Chalon-sur-Saône, a mis au jour une voie, une petite zone funéraire, ainsi que quatre aires d’occupation témoignant de la présence de bâtiments à vocation domestique et agricole (grange) occupés des deux derniers tiers du IIIe siècle au milieu du IVe siècle ap. J.-C. La distribution linéaire des vestiges sur une longueur de 1 300 m suscite un vif intérêt et pose plusieurs questions quant à la nature exacte de l’occupation. L’identification d’une petite agglomération associée à un éventuel domaine foncier fait partie des hypothèses retenues. L’analyse s’appuie sur les études du mobilier céramique et métallique ainsi que sur l’examen de lots monétaires.

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[hal-01118395] Genetic diversity of the cestode Echinococcus multilocularis in red foxes at a continental scale in Europe

19 février 2015

Alveolar echinococcosis (AE) is a severe helminth disease affecting humans, which is caused by the fox tapeworm Echinococcus multilocularis. AE represents a serious public health issue in larger regions of China, Siberia, and other regions in Asia. In Europe, a significant increase in prevalence since the 1990s is not only affecting the historically documented endemic area north of the Alps but more recently also neighbouring regions previously not known to be endemic. The genetic diversity of the parasite population and respective distribution in Europe have now been investigated in view of generating a fine-tuned map of parasite variants occurring in Europe. This approach may serve as a model to study the parasite at a worldwide level. The genetic diversity of E. multilocularis was assessed based upon the tandemly repeated microsatellite marker EmsB in association with matching fox host geographical positions. Our study demonstrated a higher genetic diversity in the endemic areas north of the Alps when compared to other areas. The study of the spatial distribution of E. multilocularis in Europe, based on 32 genetic clusters, suggests that Europe can be considered as a unique global focus of E. multilocularis, which can be schematically drawn as a central core located in Switzerland and Jura Swabe flanked by neighbouring regions where the parasite exhibits a lower genetic diversity. The transmission of the parasite into peripheral regions is governed by a "mainland-island" system. Moreover, the presence of similar genetic profiles in both zones indicated a founder event.

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[hal-00404490] Dioxin emissions from a municipal solid waste incinerator and risk of invasive breast cancer : a population-based case-control study with GIS-derived exposure.

9 décembre 2014

BACKGROUND: To date, few epidemiologic studies have examined the relationship between environmental PCDD/F exposure and breast cancer in human populations. Dioxin emissions from municipal solid waste incinerators (MSWIs) are one of the major sources of environmental dioxins and are therefore an exposure source of public concern. The purpose of this study was to examine the association between dioxins emitted from a polluting MSWI and invasive breast cancer risk among women residing in the area under direct influence of the facility. METHODS: We compared 434 incident cases of invasive breast cancer diagnosed between 1996 and 2002, and 2170 controls randomly selected from the 1999 population census. A validated dispersion model was used as a proxy for dioxin exposure, yielding four exposure categories. The latter were linked to individual places of residence, using Geographic Information System technology. RESULTS: The age distribution at diagnosis for all cases combined showed a bimodal pattern with incidence peaks near 50 and 70 years old. This prompted us to run models separately for women aged 20-59 years, and women aged 60 years or older. Among women younger than 60 years old, no increased or decreased risk was found for any dioxin exposure category. Conversely, women over 60 years old living in the highest exposed zone were 0.31 time less likely (95% confidence interval, 0.08-0.89) to develop invasive breast cancer. CONCLUSION: Before speculating that this decreased risk reflects a dioxin anti-estrogenic activity with greater effect on late-onset acquired breast cancer, some residual confounding must be envisaged.

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[hal-00419165] Lateglacial and Holocene climate oscillations in the South−western Alps : An attempt at quantitative reconstruction

4 décembre 2014

The high topographic complexity of the Alpine region is at the origin of important climate differences which characterise the different areas of the Alps. These differences might have had a strong influence on vegetation and on migrations of human populations in the past. Based on an improved data base containing about 3000 modern pollen samples, the standard “Modern Analogue Technique” has been applied to five pollen sequences from the subalpine belt of the South-western Italian Alps (Laghi dell'Orgials, 2240 m, Lago delle Fate, 2130 m, Torbiera del Biecai, 1920 m, Rifugio Mondovì, 1760 m, Pian Marchisio, 1624 m) to provide quantitative climate estimates for the Lateglacial and Holocene periods. Consistent climate trends are reconstructed for the different sequences. Sites recorded in detail the climate variations when they were located at the limit of two ecotones. Sites above the tree line recorded lower temperature values and less important variations. Climate was cold and dry during the Oldest and Younger Dryas and close to present-day values during the Bølling/Allerød interstadial. At the beginning of the Holocene, climate changed to warmer and moister conditions; a high number of climate fluctuations are recorded at several sites. A climate optimum is recorded in the Atlantic period, which caused a development of fir above its present-day altitudinal distribution. Climatic differences recorded at the various sites are discussed taking into account the limits of the method.

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[halshs-00327013] Une économie pastorale dans le nord du Vercors : analyse pluridisciplinaire des "fumiers" néolithiques et protohistoriques de la Grande Rivoire (Saussenage, Isère)

3 décembre 2014

The neolithic levels of the rock-shelter "La Grande Rivoire" are composed of a multitude of sedimentary layers of very contrasting colour. Sedimentological analyses show that the fine fractions, mainly silty and rather strongly carbonated, have principally two origins : on the one hand an important accumulation of herbivores faeces due to the repeated penning of flocks (presence of calcite spheruliths, high concentrations of organic matter, high rate of phosphate), on the other hand a large production of ashes from fire kindled directly on the dung or in nearby hearths. Animal bones of domestic species found in these dung levels show a large predominancy of goat/sheep over ox and pig. Archaeobotanical studies suggest a fodder/litter supply based on leafy and flowering tree branches. The protohistoric levels are differents from the neolithic ones : ashy layers are missing whereas natural detritic components are better represented. Nevertheless, the analysis of thin sections from these levels shows the lasting presence of speruliths and phytoliths. This indicates that stabling was during the Bronze and Iron Ages still practiced in the rock-shelter.

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[hal-00374582] A novel nonsymbiotic hemoglobin from oak : cellular and tissue specificity of gene expression.

1er décembre 2014

This study presents the isolation and characterization of a novel nonsymbiotic Hb gene from sessile oak (Quercus petraea) seedlings, herein designated QpHb1. The cellular and tissue expression of QpHb1 was analysed by Northern blotting and in situ hybridization. The encoded protein was predicted to consist of 161 amino acid residues, and shares 71 and 51% amino acid sequence identity with the Arabidopsis class 1 and 2 nonsymbiotic Hb, respectively. Northern blot analysis revealed that QpHb1 was strongly expressed in roots. Spatial expression analysis of QpHb1 in the root apical region of sessile oak by in situ hybridization indicated that transcripts were mostly abundant in protoxylem cell initials, some cortical cells and the protoderm. In addition, when comparing the expression profile of QpHb1 in sessile and pedunculate oak (Quercus robur), two species with contrasted hypoxia tolerance, the transcript level of QpHb1 rose early in the most flood-tolerant species, pedunculate oak, during root submergence. The spatial-temporal expression of QpHb1 suggests that this gene could participate in perception and signalling during hypoxia.

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[hal-00425507] A novel non-symbiotic hemoglobin from oak : Cellular and tissue specificity of gene expression

1er décembre 2014

This study presents the isolation and characterization of a novel nonsymbiotic Hb gene from sessile oak ( Quercus petraea ) seedlings, herein designated QpHb1 . • The cellular and tissue expression of QpHb1 was analysed by Northern blotting and in situ hybridization. • The encoded protein was predicted to consist of 161 amino acid residues, and shares 71 and 51% amino acid sequence identity with the Arabidopsis class 1 and 2 nonsymbiotic Hb, respectively. Northern blot analysis revealed that QpHb1 was strongly expressed in roots. Spatial expression analysis of QpHb1 in the root apical region of sessile oak by in situ hybridization indicated that transcripts were mostly abundant in protoxylem cell initials, some cortical cells and the protoderm. In addition, when comparing the expression profile of QpHb1 in sessile and pedunculate oak (Quercus robur), two species with contrasted hypoxia tolerance, the transcript level of QpHb1 rose early in the most flood-tolerant species, pedunculate oak, during root submergence. • The spatial–temporal expression of QpHb1 suggests that this gene could participate in perception and signalling during hypoxia.

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[halsde-00402793] Late-glacial and Holocene vegetation dynamics at various altitudes in the Ellero Valley, Maritime Alps, nortwestern Italy

28 novembre 2014

This study aims to reconstruct the variations of the vegetation zonation in the Ellero Valley (Maritime Alps, Italy) since the Late-glacial. Based on the analysis of percentages of dominant pollen taxa (Pinus, Abies, Fagus, deciduous Quercus, Artemisia, Poaceae) in sediment cores from three peat bogs at different altitudes (Pian Marchisio, 1624 m, Rifugio Mondovì, 1760 m and Torbiera del Biecai, 1920 m) this study offers an interpretation of pollen percentages in terms of vegetation cover. The correlation of the pollen zones in the three diagrams is validated by correspondence analysis and supported by twelve 14C (AMS) dates. The Oldest and the Younger Dryas are characterized by steppe vegetation dominated by Artemisia. The Bølling/Allerød warming which separates the Oldest and the Younger Dryas is characterized by a Pinus shift. Pine and birch forests develop at 1900 m asl at the beginning of the Holocene. The fir-wood colonization of the mountainous and subalpine belts is dated 9540-9406 cal. years BP and follows these first phases. Fir development and the arrival of beech are dated 8767-8543 cal. years BP: beech is recorded about 1000-2000 years earlier than in the adjacent regions. It develops between 1100 and 1600 m asl, forming a vegetation belt between the oak-wood in the lowland and the subalpine fir-wood. Fir decreases from 2792-2459 cal. years BP. Since this period, a beech-fir mountainous belt has been present at 1700 m. Both the suppression of the fir-forest and the lowering of the upper beech-wood limit to 1500 m are due to human activity during the last millennium.

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[hal-00361183] Du sanctuaire celtique au sanctuaire gallo-romain : quelques exemples du nord-est de la Gaule

29 octobre 2014

Nous proposons de caractériser, à partir de trois sites importants de Bourgogne et Franche-Comté, deux en cours d'étude (Mirebeau-sur-Bèze – Côte-d'Or, Mandeure – Doubs), un publié récemment (Nuits-Saint-Georges - Côte-d'Or), les évolutions contrastées que connaissent les sanctuaires liés à des agglomérations à la fin de l'âge du Fer et au Haut-Empire. Trois aspects principaux seront privilégiés : topographie, architecture, pratiques rituelles. A travers ces trois exemples, on s'aperçoit que les transformations que connaissent les sanctuaires laténiens à l'époque romaine ne correspondent pas à un processus linéaire. On observe en effet des évolutions contrastées, au sein des quelles il est difficile de faire la part exacte de l'héritage celtique (tant il nous manque de données précises permettant de cerner le poids territorial, symbolique, religieux des ces sanctuaires) et des modèles réformateurs romains.

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[hal-01066423] SPATIAL ANALYSIS OF SALT SPRINGS EXPLOITATION IN MOLDAVIAN PRE-CARPATIC PREHISTORY (ROMANIA)

23 septembre 2014

This paper presents the first results of the spatial analysis concerning the dynamics and interaction betweensettlement patterns from the Neolithic to Chalcolithic times (6000-3500 BC) and a particular mineral re-source exploited since the Early Neolithic, the salt springs in the Oriental Carpathian Mountains. Using kernel densities and viewsheds, we propose some natural and anthropological factors which structure this regionalterritory

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[halshs-00982906] Confidence maps : a tool to evaluate data’s relevance in spatial analysis.

24 avril 2014

Inventory data used in archaeology are often incomplete and heterogeneous. In the framework of the ArchaeDyn program, a method has been proposed to evaluate heterogeneity in archaeological inventories. The purpose of this work is to create a validation tool to interpret the results. This tool is called a "confidence map" and is produced by combining representation and reliability maps. The first step consists in generating representation maps to describe the clustering of archaeological items. The second step is based on reliability maps. Data providers are asked to define and outline the level of reliability of their data. Finally, representation and reliability layers are combined using map algebra. The resulting maps allow for the comparison and analysis of data confidence

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Confidence maps : a tool to evaluate data’s relevance in spatial analysis.

24 avril 2014

Inventory data used in archaeology are often incomplete and heterogeneous. In the framework of the ArchaeDyn program, a method has been proposed to evaluate heterogeneity in archaeological inventories. The purpose of this work is to create a validation tool to interpret the results. This tool is called a "confidence map" and is produced by combining representation and reliability maps. The first step consists in generating representation maps to describe the clustering of archaeological items. The second step is based on reliability maps. Data providers are asked to define and outline the level of reliability of their data. Finally, representation and reliability layers are combined using map algebra. The resulting maps allow for the comparison and analysis of data confidence

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[halshs-00482570] Approche archéologique et environnementale des premiers peuplements alpins autour du col du Petit Saint-Bernard (Savoie, Vallée d’Aoste) : un bilan d’étape

14 février 2014

De 2003 à 2007, une étude archéologique et sédimentaire a été réalisée sur les versants du col du Petit-Saint-Bernard (2188 m, Alpes occidentales), par de grandes séries de sondages manuels effectués dans des contextes sélectionnés. Les avantages et les inconvénients de cette méthodologie sont exposés et discutés. Ce travail a permis d'identifier, interstratifiés dans les remplissages holocènes, des sols bruns fersiallitiques sur les versants et des sols hydromorphes en altitude. Les répartitions chronologique et altitudinale des découvertes archéologiques sont analysées, puis comparées à une compilation des connaissances préexistantes dans les vallées alpines du Beaufortin, de la Maurienne et de la Tarentaise. Les analyses paléo-environnementales et archéologiques en cours sont présentées.

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[hal-00333253] Le lac du Bourget (Savoie, France) à l’Âge du Bronze : végétation, impacts anthropiques et climat

25 septembre 2013

L'étude de trois analyses polliniques effectuées sur les sites archéologiques de Chindrieux (Châtillon) et de Tresserve (Le Saut de la Pucelle), sur la rive est du lac du Bourget (Savoie, France) permet de reconstituer l'histoire de la végétation et des impacts anthropiques au cours de la période de l'Âge du Bronze. La fin du Néolithique et le Bronze ancien sont caractérisés par une occupation discrète des alentours du Bourget et donc par un faible impact anthropique sur l'environnement très forestier, en dépit d'un climat plutôt favorable. La période du Bronze moyen, contemporaine d'une péjoration climatique, correspond à la quasi-disparition de tout impact anthropique. Le début du Bronze final voit le retour toujours discret des activités humaines, activités qui s'amplifient soudainement au cours de la fin du Bronze final. On observe alors une tripartition des événements : une courte phase de transgression lacustre et de déprise agricole scinde la fin du Bronze final. Le début de l'Âge du Fer correspond à une nouvelle déprise agricole. Dans une dernière partie, les résultats des analyses paléoclimatiques et chimiques obtenues sur un forage profond au milieu du lac sont intégrés aux résultats polliniques.

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Le lac du Bourget (Savoie, France) à l’Âge du Bronze : végétation, impacts anthropiques et climat

25 septembre 2013

L'étude de trois analyses polliniques effectuées sur les sites archéologiques de Chindrieux (Châtillon) et de Tresserve (Le Saut de la Pucelle), sur la rive est du lac du Bourget (Savoie, France) permet de reconstituer l'histoire de la végétation et des impacts anthropiques au cours de la période de l'Âge du Bronze. La fin du Néolithique et le Bronze ancien sont caractérisés par une occupation discrète des alentours du Bourget et donc par un faible impact anthropique sur l'environnement très forestier, en dépit d'un climat plutôt favorable. La période du Bronze moyen, contemporaine d'une péjoration climatique, correspond à la quasi-disparition de tout impact anthropique. Le début du Bronze final voit le retour toujours discret des activités humaines, activités qui s'amplifient soudainement au cours de la fin du Bronze final. On observe alors une tripartition des événements : une courte phase de transgression lacustre et de déprise agricole scinde la fin du Bronze final. Le début de l'Âge du Fer correspond à une nouvelle déprise agricole. Dans une dernière partie, les résultats des analyses paléoclimatiques et chimiques obtenues sur un forage profond au milieu du lac sont intégrés aux résultats polliniques.

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[hal-00803977] Les vestiges gallo-romains conservés dans le massif forestier de Haye (Meurthe-et-Moselle). Leur apport à l’étude de l’espace agraire.

24 mars 2013

Les grandes forêts implantées sur le plateau calcaire des revers de la Côte de Moselle, entre Nancy et Neufchâteau en Lorraine, recèlent de nombreuses structures agraires et parcellaires d'époque gallo-romaine conservées sous forme de micro-reliefs. Depuis 2000, les travaux de l'équipe pluridisciplinaire qui travaille sur ces vestiges portent sur le massif forestier de Haye, d'une superficie de 12000 ha. A côté de méthodes classiques (prospections pédestres, sondages, etc), des techniques plus nouvelles ont pu être mobilisées pour cette étude, comme le laser scanneur aéroporté (ou LiDAR) ou l'analyse spatiale grâce à un système d'information géographique. Après une présentation détaillée des divers vestiges étudiés (structures agraires et parcellaires, réseau viaire, nécropole, habitats), les problèmes de datation sont analysés et des réflexions sur la place de ce type d'occupation dans le monde rural antique sont proposées.

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Neighbourhood landscape effect on population kinetics of the fossorial water vole (Arvicola terrestris scherman)

13 septembre 2012

This paper addresses the issue of whether landscape structure affects A. terrestris population kinetics on a neighbourhood spatial scale, and if so, at what spatial scale is that effect at its maximum. We investigated how the growth of A. terrestris populations is influenced by the landscape context of parcels used for hay production in the French Jura Mountains. Five landscape metrics (relative area of grassland, mean patch area of grassland, patch density of grassland, woodland patch density in grassland, grassland-woodland edge density) were computed over an increasing radius around each parcel (max. 3 km). Redundancy analysis showed that the extent, rate and early onset of A. terrestris population growth were favoured in open grassland areas. Landscape effects on A. terrestris populations as determined by the five metrics are scale-dependent: mean patch area of grassland, patch density of grassland and woodland patch density in grassland had an impact on a grassland parcel within a neighbourhood radius of about 800 m, while relative area of grassland and grassland-woodland edge density had an impact within a neighbourhood radius of about 400 m. Those findings corroborate earlier hypotheses about a multifactorial regulation of A. terrestris populations and a spatial hierarchy of regulating factors. They have potential implications in terms of landscape management and small mammal pest control.

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[tel-00725019] Recherche de marqueurs physiologiques de tolérance à l’ennoyage chez le chêne pédonculé (Quercus robur L.) et chez le chêne sessile (Quercus petraea [Matt] Liebl.)

30 août 2012

Ce travail a pour objectif d'améliorer la connaissance des mécanismes physiologiques qui président à la tolérance à l'ennoyage du chêne. La principale contrainte de l'ennoyage est un déficit en oxygène (hypoxie). Les réponses à ce stress sont étudiées chez le chêne pédonculé (réputé tolérant) et le chêne sessile (plus sensible), à des stades précoces de développement des semis, en présence des cotylédons. Une période de drainage est incluse pour mimer un ennoyage temporaire. La croissance des semis a été suivie, notamment au niveau de l'architecture racinaire. La contribution de la nutrition azotée (assimilation et allocation) a été évaluée en suivant au préalable le devenir des éléments minéraux azotés dans la rhizosphère. La gestion des réserves glucidiques (amidon et sucres solubles) des organes de réserve (cotylédons) et des organes en croissance lors du développement des semis a été mise en relation avec la tolérance à l'ennoyage des chênes. Il ressort des paramètres de croissance étudiés que l'ennoyage a peu d'effets sur la première vague de croissance foliaire mais inhibe la deuxième vague, alors que la croissance racinaire est particulièrement inhibée. Néanmoins, le chêne pédonculé est capable d'une forte colonisation racinaire des horizons superficiels du sol ennoyé et, après drainage, son aptitude à régénérer des racines est plus efficace que chez le chêne sessile. Dans la rhizosphère, l'ennoyage entraîne un basculement réversible des formes azotées nitrates / ammonium. Les modifications du métabolisme azoté sont globalement similaires entre les deux espèces. L'assimilation de l'azote, via la nitrate réductase et la glutamine synthétase, n'est pas réellement perturbée mais, les deux espèces présentent une carence azotée au niveau foliaire. L'assimilation et l'allocation azotée n'apparaissent pas comme des traits discriminants de la tolérance à l'ennoyage chez ces espèces. Sous ennoyage, l'accumulation totale d'amidon est réduite mais elle reste active dans la partie basale du pivot et dans la tige des deux espèces. Elle est cependant plus élevée chez le chêne pédonculé. L'ennoyage restreint la mobilisation des réserves cotylédonaires d'amidon, notamment chez le chêne pédonculé. L'activité des α amylases cotylédonaires corrobore le taux de mobilisation de l'amidon. La tolérance à l'ennoyage des semis de chêne n'est pas associée à une stimulation de la mobilisation des réserves glucidiques cotylédonaires. Le chêne pédonculé serrait plus économe en glucide que le chêne sessile (faible mobilisation cotylédonaire / stockage d'amidon élevé / meilleure croissance). Cette particularité pourrait constituer un marqueur physiologique important de la tolérance à l'ennoyage chez les chênes.

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[tel-00725019] Recherche de marqueurs physiologiques de tolérance à l’ennoyage chez le chêne pédonculé (Quercus robur L.) et chez le chêne sessile (Quercus petraea [Matt] Liebl.)

30 août 2012

The aim of this study was to improve knowledge on physiological patterns of oak trees' tolerance to waterlogging (or flooding), in order to discriminate useful settings to assess their tolerance potential. In plants the main constraint caused by flooding is the lack of oxygen (root hypoxia) leading to an energy crisis. The responses to this stress were investigated under controlled conditions in two sympatric oak species known to display different ecological requirements, particularly relative to waterlogging. The tolerant pedunculate oak and the more sensitive sessile oak were studied at the early stage of seedling development, in presence of their cotyledons. Potted seedlings were submitted during two flush of growth to a waterlogging or a control treatment. A drainage stage following the waterlogging was included in a third treatment to mimic a temporary soil flooding (most usual cases on the field). One part of the study was related to seedling growth development, especially root distribution. A second part deals with nitrogen nutrition (assimilation and allocation), that was previously assessed by monitoring changes in mineral nitrogen composition of the rhizosphere. Finally, a third part examines the pattern of carbohydrate management (starch and soluble carbohydrates). In both species, the first flush of growth was not inhibited by waterlogging whereas the second flush was severely disrupted, while the root growth was drastically reduced. Nevertheless, pedunculate oak showed a stronger root system than sessile oak, especially by maintaining root colonization in the shallow waterlogged soil layer (adventitious roots). Moreover, pedunculate oak showed the ability to regenerate a strong root system quickly after drainage. The growth recovery of pedunculate oak seedlings was greater than that of sessile oak, allowing its better establishment on hydromorphic soils since the early stage of seedlings. The nitrogen monitoring in the rhizospheric flooded soil showed a switch from nitrate to ammonia, reversible after drainage. The nitrogen metabolism was similar in the two oak species. The key enzymatic activities of the nitrogen assimilation pathway (nitrate reductase and glutamine synthetase) were not clearly affected in the roots neither in the leaves. However, under waterlogging the two oak species showed nitrogen deficiency in the leaves. Overall, nitrogen nutrition is not a feature of waterlogging tolerance which can discriminate these two oak species. The total starch content of waterlogged seedlings was significantly decreased in both species but starch accumulation process remained active, especially in the first flush stem and in the upper taproot section. The overall management of carbohydrates was significantly different between the two oak species when subjected to waterlogging. Under waterlogging, pedunculate oak showed both starch accumulation and a growth rate higher than sessile oak, while carbohydrate mobilization from cotyledons was delayed by waterlogging especially in pedunculate oak seedlings. The α-amylase enzyme activity in cotyledons was corroborated at the rate of starch mobilization. Unlike crop plants (e.g. rice, wheat), tolerance to waterlogging of oak seedlings was not related to higher rates of carbohydrate mobilization from cotyledons. Pedunculate oak seems able to save its carbohydrate reserves until the growth conditions are more favourable and therefore it was able to better sustain a fast and strong recovery after drainage. Over the duration of the experiments, despite a growth limitation, waterlogged seedlings did not seem under carbon limitation because soluble carbohydrate availability was maintained in roots. However, the obtained results showed a carbon imbalance in sessile oak seedlings. Thus, carbon limitation and then carbohydrate starvation could take place. The features of carbohydrate management, related to the whole plant's carbon metabolism, and root growth appear crucial in tolerance to waterlogging. These physiological patterns are usable at the seedling stage to assess their waterlogging tolerance.

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Collaborative and Cybernetic Driving

24 mai 2012

This documents presents main collaborative driving applications, along with definitions regarding context modeling, wireless communications, satellite positionning and digital maps.

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Middleware Models for Location-Based Services : a Survey

24 mai 2012

Embedded computing systems, sensor networks, LBS pervasive deployment environments, and worldwide computing systems have common characteristics. They are large scale, decentralized and dynamic networks, and needing context-awareness to automatically adapt their behavior and continue their execution despite network dynamics. Identifying innovative software engineering approaches that take into account all the above mentioned characteristics is a real challenge. This paper focuses on LBS applications and the middleware models required for supporting their operation and characteristics.

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Location Models for Pervasive Road Networks

24 mai 2012

Context-aware mobile computing aims at designing applications that automatically adapt their behaviors to the available location information and the available nearby sensors and devices. This is done in order to fulfill tasks in a way that suits users' current context best. To achieve this, context representation and manipulation are important issues, so as to establish formal context models. In this paper, basic elements of context-aware systems are described with an emphasis on location information representations. Space models for location-based applications are presented. Considered realistic applications concern intelligent vehicles and pervasive road networks.

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[hal-00448378] Effects of experimental warming on carbon sink function of a temperate pristine mire : the PEATWARM project.

11 avril 2012

Within the PEATWARM project, we use Sphagnum peatlands as a model to analyse their vulnerability to climate change using an experimental system (ITEX) that simulates in situ an increase in average temperature. We aim to determine the effects of temperature increase on the vegetation, the balance of above- and belowground gas fluxes (CO2 and CH4), the microbial diversity and activity in Sphagnum mosses and in peat, and the dynamics of labile and recalcitrant organic matter of peat. The ultimate objective is the creation of a biogeochemical model of C coupled with N and S cycles that includes interactions between these key compartments.

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Effects of experimental warming on carbon sink function of a temperate pristine mire : the PEATWARM project.

10 avril 2012

Within the PEATWARM project, we use Sphagnum peatlands as a model to analyse their vulnerability to climate change using an experimental system (ITEX) that simulates in situ an increase in average temperature. We aim to determine the effects of temperature increase on the vegetation, the balance of above- and belowground gas fluxes (CO2 and CH4), the microbial diversity and activity in Sphagnum mosses and in peat, and the dynamics of labile and recalcitrant organic matter of peat. The ultimate objective is the creation of a biogeochemical model of C coupled with N and S cycles that includes interactions between these key compartments.

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[hal-00675014] Reductive unfolding of serum albumine uncovered by Raman spectroscopy

28 février 2012

The reductive unfolding of bovine serum albumin (BSA) and human serum albumin (HSA) induced by dithiothreitol (DTT) is investigated using Raman spectroscopy. The resolution of the S-S Raman band into both protein and oxidized DTT contributions provides a reliable basis for directly monitoring the S-S bridge exchange reaction. The related changes in the protein secondary structure are identified by analyzing the protein amide I Raman band. For the reduction of one S-S bridge of BSA a mean Gibbs free energy of -7 kJ mol-1 is derived by studying the reaction equilibrium. The corresponding value for the HSA S-S bridge reduction is -2 kJ mol-1. The reaction kinetics observed via the S-S or amide I Raman bands are identical giving a reaction rate constant of (1.02 0.11) M-1 s-1 for BSA. The contribution of the conformational Gibbs free energy to the overall Gibbs free energy of reaction is further estimated by combining experimental data with ab initio calculations.

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Reductive unfolding of serum albumine uncovered by Raman spectroscopy

28 février 2012

The reductive unfolding of bovine serum albumin (BSA) and human serum albumin (HSA) induced by dithiothreitol (DTT) is investigated using Raman spectroscopy. The resolution of the S-S Raman band into both protein and oxidized DTT contributions provides a reliable basis for directly monitoring the S-S bridge exchange reaction. The related changes in the protein secondary structure are identified by analyzing the protein amide I Raman band. For the reduction of one S-S bridge of BSA a mean Gibbs free energy of -7 kJ mol-1 is derived by studying the reaction equilibrium. The corresponding value for the HSA S-S bridge reduction is -2 kJ mol-1. The reaction kinetics observed via the S-S or amide I Raman bands are identical giving a reaction rate constant of (1.02 0.11) M-1 s-1 for BSA. The contribution of the conformational Gibbs free energy to the overall Gibbs free energy of reaction is further estimated by combining experimental data with ab initio calculations.

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[hal-00425503] An overview of plant responses to soil waterlogging

7 février 2012

Under natural conditions, plants are frequently exposed to transient or permanent soil waterlogging. Flooding drastically influences the soil physico-chemical properties, most notably soil redox potential, pH and O2 level. Thus, conditions of hypoxia or anoxia are commonly encountered by plant root systems. These O2 restrictive conditions dramatically affect plant growth, development and survival. One of the best characterised plant responses to soil waterlogging is the metabolic switch from aerobic respiration to anaerobic fermentation. In fact, most proteins induced during hypoxic conditions are enzymes involved in the establishment of this fermentative pathway. Because the plant cells need to keep a continuous ATP supply, the use of alternative electron acceptors and/or alternative pathways may be key elements of survival under soil waterlogging. The plant response may also include a reduction in stomatal conductance and photosynthesis, as well as root hydraulic conductivity. These physiological modifications may in turn affect carbohydrate reserves and translocation. In fact, efficient use of carbohydrates may discriminate between tolerant and intolerant species. Other observed adaptations include morphological changes which comprise the formation of hypertrophied lenticels, the initiation of adventitious roots and/or the development of aerenchyma. Our knowledge of the basic adaptive mechanisms of plants to soil waterlogging has benefited from large scale genomic and proteomic approaches, however, the diversity of the adaptive responses involved underlines the difficulty when studying this stress. This update reviews our current comprehension of the metabolic, physiological and morphological responses and adaptations of plants to soil waterlogging.

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[halsde-00664901] Du climat à l’homme : Dynamique holocène de l’environnement dans le jura et les alpes Actes du colloque GDR JURALP organisé à Aix-en-Provence les 15 et 16 novembre 2007

6 février 2012

Ce volume constitue les actes de la table ronde qui s'est tenue les 15 et 16 novembre 2007 à la Maison Méditerranéenne des Sciences de l'Homme d'Aix-en-Provence, et qui a été organisée dans le cadre du GDR 2992 du CNRS, JurAlpes, sur le thème " Dynamique holocène de l'environnement dans le Jura et les Alpes : du climat à l'homme ". Les dix huit contributions rassemblées dans cet ouvrage couvrent un large éventail de champs disciplinaires et de méthodes d'étude. Après les deux premiers chapitres dédiés successivement aux reconstitutions des fluctuations des glaciers des Alpes occidentales depuis 5000 ans (P. Deline et M. Le Roy) et à l'usage des spéléothèmes en tant que proxy de la variabilité climatique annuelle (Y. Perrette), les cinq contributions suivantes s'appuient sur l'analyse de séquences sédimentaires lacustres (E. Chapron et al. ; M. Magny et al. ; L. Millet et al. ; F. Arnaud et al. ; A. Leroux et al.). Les lacs étudiés sont des lacs d'altitude (lac de Joux dans le Jura, lacs d'Anterne, de Bramant, de Blanc Huez et de Dessus-Verney dans les Alpes), ou des grands lacs de vallées (lacs du Bourget et de Constance, ou Bodensee). Suivent quatre chapitres qui s'intéressent aux vecteurs fluviatiles, de la vallée du Rhône (J.-P. Bravard et al. ; J.-F. Berger et al.), au bassin de la Durance (C. Miramont et al.) jusqu'au delta du Rhône (C. Vella et al.). Viennent ensuite trois contributions qui sont plus particulièrement centrées sur l'histoire du couvert végétal et de la pédogénèse dans les zones d'altitude des Alpes en s'appuyant sur des données anthracologiques (B. Talon), dendrochronologiques (J.-L. Edouard et A. Thomas) et pédo-sédimentaires (B. Moulin et P.-J. Rey). Enfin, les quatre dernières contributions portent sur l'histoire de l'anthropisation des Alpes (P.J. Rey et al. ; P. Bintz et al. ; A. Marguet et al. ; F. Mocci et al.) et du Jura (E. Gauthier et H. Richard).

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Du climat à l’homme : Dynamique holocène de l’environnement dans le jura et les alpes Actes du colloque GDR JURALP organisé à Aix-en-Provence les 15 et 16 novembre 2007

31 janvier 2012

Ce volume constitue les actes de la table ronde qui s'est tenue les 15 et 16 novembre 2007 à la Maison Méditerranéenne des Sciences de l'Homme d'Aix-en-Provence, et qui a été organisée dans le cadre du GDR 2992 du CNRS, JurAlpes, sur le thème " Dynamique holocène de l'environnement dans le Jura et les Alpes : du climat à l'homme ". Les dix huit contributions rassemblées dans cet ouvrage couvrent un large éventail de champs disciplinaires et de méthodes d'étude. Après les deux premiers chapitres dédiés successivement aux reconstitutions des fluctuations des glaciers des Alpes occidentales depuis 5000 ans (P. Deline et M. Le Roy) et à l'usage des spéléothèmes en tant que proxy de la variabilité climatique annuelle (Y. Perrette), les cinq contributions suivantes s'appuient sur l'analyse de séquences sédimentaires lacustres (E. Chapron et al. ; M. Magny et al. ; L. Millet et al. ; F. Arnaud et al. ; A. Leroux et al.). Les lacs étudiés sont des lacs d'altitude (lac de Joux dans le Jura, lacs d'Anterne, de Bramant, de Blanc Huez et de Dessus-Verney dans les Alpes), ou des grands lacs de vallées (lacs du Bourget et de Constance, ou Bodensee). Suivent quatre chapitres qui s'intéressent aux vecteurs fluviatiles, de la vallée du Rhône (J.-P. Bravard et al. ; J.-F. Berger et al.), au bassin de la Durance (C. Miramont et al.) jusqu'au delta du Rhône (C. Vella et al.). Viennent ensuite trois contributions qui sont plus particulièrement centrées sur l'histoire du couvert végétal et de la pédogénèse dans les zones d'altitude des Alpes en s'appuyant sur des données anthracologiques (B. Talon), dendrochronologiques (J.-L. Edouard et A. Thomas) et pédo-sédimentaires (B. Moulin et P.-J. Rey). Enfin, les quatre dernières contributions portent sur l'histoire de l'anthropisation des Alpes (P.J. Rey et al. ; P. Bintz et al. ; A. Marguet et al. ; F. Mocci et al.) et du Jura (E. Gauthier et H. Richard).

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[halshs-00483146] Settlement pattern and hierarchy :methods and comparison in Languedoc (France) and Istria (Slovenia)

7 septembre 2011

Final post-doc report of Saso Poglajen (LEA ModeLTER/Charles Nodier scholarship MAE) The aim the research was to test if there is possibility to compare a good quality settlement distribution data with the pore quality data. The case studies were Languedoc1 in France with good data and north-western Istria (Croatia, Italy and Slovenia) with bad quality data.

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[halshs-00483129] Lidor. Acquisition, traitement et analyse d’images LiDAR pour la modélisation des paléo-reliefs de la plaine littorale du Languedoc oriental.

7 septembre 2011

Rapport final du programme ATIP LidOR. Acquisition et traitement de données Lidar acquises en décembre 2006 dans la plaine littorale de Mauguio. L'ensemble des données Lidar acquises a pu être traité pour produire un premier Modèle Numérique de Terrain puis de Surface à 50 cm de résolution qui ont permis une exploration visuelle des données. D'un point de vue thématique, le travail de l'équipe s'est concentré sur le traitement des données avec trois objectifs principaux : la détection des aménagements de la plaine (irrigation, drainage...) depuis l'Antiquité ; la mise en évidence du réseau hydrographique " naturel " avant le détournement artificiel des cours d'eau et l'assèchement des dépressions humides ; la détection des microreliefs résiduels.

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[hal-00404911] Path modelling and settlement pattern

30 août 2011

This paper describes the contribution of path modelling to the ancient settlement pattern study over the long term. The path modelling methodology is a stimulating tool, which is complementary to the hierarchical approaches in the landscape archaeology since it contributes to the understanding of the spatial relation between archaeological sites. The existing methodology was enhanced by enlarging the set of path reconstitution parameters (visibility) and by modelling in two scales. The proposed model is based on parameters derived merely from the relief because its changes should be insignificant even over a long period time

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Settlement pattern and hierarchy :methods and comparison in Languedoc (France) and Istria (Slovenia)

27 août 2011

Final post-doc report of Saso Poglajen (LEA ModeLTER/Charles Nodier scholarship MAE) The aim the research was to test if there is possibility to compare a good quality settlement distribution data with the pore quality data. The case studies were Languedoc1 in France with good data and north-western Istria (Croatia, Italy and Slovenia) with bad quality data.

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Lidor. Acquisition, traitement et analyse d’images LiDAR pour la modélisation des paléo-reliefs de la plaine littorale du Languedoc oriental.

27 août 2011

Rapport final du programme ATIP LidOR. Acquisition et traitement de données Lidar acquises en décembre 2006 dans la plaine littorale de Mauguio. L'ensemble des données Lidar acquises a pu être traité pour produire un premier Modèle Numérique de Terrain puis de Surface à 50 cm de résolution qui ont permis une exploration visuelle des données. D'un point de vue thématique, le travail de l'équipe s'est concentré sur le traitement des données avec trois objectifs principaux : la détection des aménagements de la plaine (irrigation, drainage...) depuis l'Antiquité ; la mise en évidence du réseau hydrographique " naturel " avant le détournement artificiel des cours d'eau et l'assèchement des dépressions humides ; la détection des microreliefs résiduels.

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Do ridge-ridge-fault triple junctions exist on Earth ? Evidence from the Aden-Owen-Carlsberg junction in the NW Indian Ocean

31 mars 2011

The triple junctions predicted to be ridge^ridge^fault (RRF) types on the basis of large- scale plate motions are theAzores triple junction between theGloria Fault and theMid-AtlanticRidge, the Juan Fernandez triple junction between the ChileTransform and the East Paci¢c Rise and the Aden^ Owen^Carlsberg (AOC) triple junction between theOwen fracture zone (OFZ) and theCarlsberg and Sheba ridges. In the ¢rst two cases, the expected RRF triple junction does not exist because the transform fault arm of the triple junction has evolved into a divergent boundary before connecting to the ridges.Here, we report the results of a marine geophysical survey of the AOC triple junction, which took place in 2006 aboard the R/VBeautemps-Beaupre¤.We show that a rift basin currently forms at the southern end of theOFZ, indicating that a divergent plate boundary between Arabia and India is developing at the triple junction.The connection of this boundary with the Carlsberg and Sheba ridges is not clearly delineated and the triple junction presently corresponds to awidespread zone of distributed deformation.The AOC triple junction appears to be in a transient stage between a former triple junction of the ridge^fault^fault type and a future triple junction of the ridge^ridge^ridge (RRR) type. Consequently, the known three examples of potential RRF triple junctions are actually of the RRR type, and RRF triple junctions do not presently exist on Earth

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[hal-00581775] Do ridge-ridge-fault triple junctions exist on Earth ? Evidence from the Aden-Owen-Carlsberg junction in the NW Indian Ocean

31 mars 2011

The triple junctions predicted to be ridge^ridge^fault (RRF) types on the basis of large- scale plate motions are theAzores triple junction between theGloria Fault and theMid-AtlanticRidge, the Juan Fernandez triple junction between the ChileTransform and the East Paci¢c Rise and the Aden^ Owen^Carlsberg (AOC) triple junction between theOwen fracture zone (OFZ) and theCarlsberg and Sheba ridges. In the ¢rst two cases, the expected RRF triple junction does not exist because the transform fault arm of the triple junction has evolved into a divergent boundary before connecting to the ridges.Here, we report the results of a marine geophysical survey of the AOC triple junction, which took place in 2006 aboard the R/VBeautemps-Beaupre¤.We show that a rift basin currently forms at the southern end of theOFZ, indicating that a divergent plate boundary between Arabia and India is developing at the triple junction.The connection of this boundary with the Carlsberg and Sheba ridges is not clearly delineated and the triple junction presently corresponds to awidespread zone of distributed deformation.The AOC triple junction appears to be in a transient stage between a former triple junction of the ridge^fault^fault type and a future triple junction of the ridge^ridge^ridge (RRR) type. Consequently, the known three examples of potential RRF triple junctions are actually of the RRR type, and RRF triple junctions do not presently exist on Earth

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In-situ evidence for dextral active motion at the Arabia-India plate boundary

31 mars 2011

The Arabia-India plate boundary--also called theOwen fracture zone--is perhaps the least-known boundary among large tectonic plates1-6. Although it was identified early on as an example of a transform fault converting the divergent motion along the Carlsberg Ridge to convergent motion in the Himalayas7, its structure and rate of motion remains poorly constrained. Here we present the first direct evidence for active dextral strike-slip motion along this fault, based on seafloor multibeam mapping of the Arabia-India-Somalia triple junction in the northwest Indian Ocean. There is evidence for 12km of apparent strike-slip motion along the mapped segment of the Owen fracture zone, which is terminated to the south by a 50-km-wide pull-apart basin bounded by active faults. By evaluating these new constraints within the context of geodetic models of global plate motions, we determine a robust angular velocity for the Arabian plate relative to the Indian plate that predicts 2-4mmyr−1 dextral motion along the Owen fracture zone. This transformfault was probably initiated around 8 million years ago in response to a regional reorganization of plate velocities and directions8-11, which induced a change in configuration of the triple junction. Infrequent earthquakes of magnitude 7 and greater may occur along the Arabia-India plate boundary, unless deformation is in the formof aseismic creep.

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[hal-00581768] In-situ evidence for dextral active motion at the Arabia-India plate boundary

31 mars 2011

The Arabia-India plate boundary--also called theOwen fracture zone--is perhaps the least-known boundary among large tectonic plates1-6. Although it was identified early on as an example of a transform fault converting the divergent motion along the Carlsberg Ridge to convergent motion in the Himalayas7, its structure and rate of motion remains poorly constrained. Here we present the first direct evidence for active dextral strike-slip motion along this fault, based on seafloor multibeam mapping of the Arabia-India-Somalia triple junction in the northwest Indian Ocean. There is evidence for 12km of apparent strike-slip motion along the mapped segment of the Owen fracture zone, which is terminated to the south by a 50-km-wide pull-apart basin bounded by active faults. By evaluating these new constraints within the context of geodetic models of global plate motions, we determine a robust angular velocity for the Arabian plate relative to the Indian plate that predicts 2-4mmyr−1 dextral motion along the Owen fracture zone. This transformfault was probably initiated around 8 million years ago in response to a regional reorganization of plate velocities and directions8-11, which induced a change in configuration of the triple junction. Infrequent earthquakes of magnitude 7 and greater may occur along the Arabia-India plate boundary, unless deformation is in the formof aseismic creep.

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Dioxin emissions from a municipal solid waste incinerator and risk of invasive breast cancer : a population-based case-control study with GIS-derived exposure.

25 juin 2010

BACKGROUND: To date, few epidemiologic studies have examined the relationship between environmental PCDD/F exposure and breast cancer in human populations. Dioxin emissions from municipal solid waste incinerators (MSWIs) are one of the major sources of environmental dioxins and are therefore an exposure source of public concern. The purpose of this study was to examine the association between dioxins emitted from a polluting MSWI and invasive breast cancer risk among women residing in the area under direct influence of the facility. METHODS: We compared 434 incident cases of invasive breast cancer diagnosed between 1996 and 2002, and 2170 controls randomly selected from the 1999 population census. A validated dispersion model was used as a proxy for dioxin exposure, yielding four exposure categories. The latter were linked to individual places of residence, using Geographic Information System technology. RESULTS: The age distribution at diagnosis for all cases combined showed a bimodal pattern with incidence peaks near 50 and 70 years old. This prompted us to run models separately for women aged 20-59 years, and women aged 60 years or older. Among women younger than 60 years old, no increased or decreased risk was found for any dioxin exposure category. Conversely, women over 60 years old living in the highest exposed zone were 0.31 time less likely (95% confidence interval, 0.08-0.89) to develop invasive breast cancer. CONCLUSION: Before speculating that this decreased risk reflects a dioxin anti-estrogenic activity with greater effect on late-onset acquired breast cancer, some residual confounding must be envisaged.

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Dioxin emissions from a municipal solid waste incinerator and risk of invasive breast cancer : a population-based case-control study with GIS-derived exposure.

25 juin 2010

BACKGROUND: To date, few epidemiologic studies have examined the relationship between environmental PCDD/F exposure and breast cancer in human populations. Dioxin emissions from municipal solid waste incinerators (MSWIs) are one of the major sources of environmental dioxins and are therefore an exposure source of public concern. The purpose of this study was to examine the association between dioxins emitted from a polluting MSWI and invasive breast cancer risk among women residing in the area under direct influence of the facility. METHODS: We compared 434 incident cases of invasive breast cancer diagnosed between 1996 and 2002, and 2170 controls randomly selected from the 1999 population census. A validated dispersion model was used as a proxy for dioxin exposure, yielding four exposure categories. The latter were linked to individual places of residence, using Geographic Information System technology. RESULTS: The age distribution at diagnosis for all cases combined showed a bimodal pattern with incidence peaks near 50 and 70 years old. This prompted us to run models separately for women aged 20-59 years, and women aged 60 years or older. Among women younger than 60 years old, no increased or decreased risk was found for any dioxin exposure category. Conversely, women over 60 years old living in the highest exposed zone were 0.31 time less likely (95% confidence interval, 0.08-0.89) to develop invasive breast cancer. CONCLUSION: Before speculating that this decreased risk reflects a dioxin anti-estrogenic activity with greater effect on late-onset acquired breast cancer, some residual confounding must be envisaged.

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[hal-00370941] [Geography of alveolar echinococcosis]

22 juin 2010

Alveolar echinococcosis is restricted geographically to the colder areas of the northern hemisphere. In France, the highest prevalence is observed in Franche-Comtd. The yearly incidence of AE in endemic areas is generally low (0.02-0.18 per 100,000 inhabitants) but it can exceed 1 per 100,000 locally. E. multilocularis transmission has intensified in traditionally in foxes endemic areas during the last twenty years, and the parasite has extended its range to new areas and countries of Europe. The increasing proximity of fox populations to urban areas may lead to a new epidemiological pattern. Control measures are only applicable at the local scale, and are essentially based on for deworming.

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[hal-00370946] [Parasite-host relationships and treatment]

22 juin 2010

Alveolar echinococcosis (AE) is a parasitic disease caused by intrahepatic growth of the larval stage of the cestode Echinococcus multilocularis. The main definitive host in Europe is the fox. The adult worms live in the fox intestine and their oncospheres are disseminated by faeces. Wolves, dogs and cats may also serve as definitive hosts. Small rodents--especially voles in Europe and small lagomorphs in Asia--are the natural intermediate hosts. The tumour-like larva is composed of multiple vesicles which produce protoscoleces, the fertile stage of the E. multilocularis metacestode. Carnivores are infected by preying on infected rodents. Like rodents, humans are intermediate hosts and are infected either by eating uncooked vegetables and berries contaminated by faeces of infected carnivores, or by touching such animals. Humans are naturally resistant to metacestode development. Genetic characteristics are involved in susceptibility/resistance to E. multilocularis metacestodes. In humans and other intermediate animal hosts, immune suppression enhances parasite growth, which is normally controlled by cytotoxic mechanisms and delayed-type hypersensitivity. Tolerance of E. multilocularis is due in part to parasite characteristics (especially carbohydrate antigens of the laminated layer) and in part to the "anti-inflammatory/tolerogenic" cytokines IL-10 and TGF-beta. Treatment with interferon-a restores a cytokine balance favorable to the host and might be a new therapeutic option for AE patients. Vaccination is a scientifically sound but economically and politically Utopian means of preventing the disease. Prevention thus relies on simple lifestyle measures: cooking potentially contaminated food, regular treatment of domestic animals with praziquantel, and precautions when touching potentially infected definitive hosts (foxes and dogs).

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Nouvelles données sur les SIG : Prospection expérimentale sur un site de hauteur. (Camp de César, Gard, France)

2 juin 2010

La prospection expérimentale qui c'est tenue sur l'oppidum du Camp de César à Laudun dans le Gard (France), a permis de démontrer qu'avec les moyens technologiques actuels, une prospection dans un milieu naturel difficile est réalisable, et qu'en plus les données qui en émane sont fiables. Au niveau des résultats archéologiques, cette prospection a confirmé l'importance du site au cours de l'antiquité et sa rétraction au cours de l'Antiquité tardive.

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Étude de la réponse à l’ennoyage chez le chêne sessile (Quercus petraea) et le chêne pédonculé (Quercus robur) : Implication de l’hémoglobine non-symbiotique

2 juin 2010

L'ennoyage est un phénomène courant qui se répercute sur les végétaux en diminuant leur croissance, leur développement et leur régénération. Il entraîne une forte diminution du taux d'oxygène (hypoxie) dans le compartiment racinaire résultat de l'excès d'eau dans le sol. Face à ce stress, certaines plantes sont capables intensifier leur métabolisme anaérobie et développer des adaptations morphologiques (lenticelles hypertrophiées, aérenchymes, racines adventives). Le chêne sessile (Quercus petraea Matt L.) et le chêne pédonculé (Quercus robur L.) présentent une différence de tolérance à l'ennoyage du sol mais sont génétiquement proches. Cependant, il existe peu de connaissances sur les processus physiologiques mis en place par ces deux espèces durant ce stress. La croissance ainsi que certains changements morphologiques, anatomiques et physiologiques étudiés chez les deux espèces en réponse à un ennoyage, ont confirmé que le chêne sessile était davantage sensible à ce stress. Le chêne pédonculé, espèce plus tolérante, parvient à maintenir son statut hydrique de même que son activité photosynthétique plus longtemps et à des niveaux moins critiques que le sessile. L'hémoglobine non-symbiotique améliore la survie des plantes en conditions d'hypoxie en interagissant avec le monoxyde d'azote (NO). Le clonage d'une hémoglobine non-symbiotique chez le chêne sessile a permis d'isoler le gène QpHb1 codant pour une protéine de 161 acides aminés et présentant toutes les caractéristiques communes aux hémoglobines non-symbiotiques de classe 1. Chez les deux espèces, QpHb1 est davantage exprimé dans les racines que dans la tige ou les feuilles, suggérant un rôle particulier dans ce tissu. L'expression de QpHb1 analysée par Northern blotting a montré une chute d'expression dans les racines dès les premières heures de stress chez le chêne sessile qui se poursuit durant toute la durée de l'expérience (28 jours). Alors que chez le chêne pédonculé, l'expression de QpHb1 suit un schéma plus complexe : on observe un pic d'expression après 1h d'ennoyage suivi d'une forte inhibition après 3h. Cette régulation pourrait être synonyme d'une implication de l'hémoglobine non-symbiotique dans la signalisation rapide du stress et par conséquent dans la mise en place de la tolérance. D'ailleurs sa localisation par hybridation in situ au niveau racinaire a montré que QpHb1 se situait au niveau des cellules du protoderme, pouvant suggérer un rôle dans la détection des modifications de la rhizosphère mais aussi au niveau du protoxylème qui pourrait lui permettre de participer à la signalisation entre l'appareil racinaire et l'appareil aérien via la S-nitrosylation. Dans la réponse à un ennoyage de plusieurs semaines, le chêne pédonculé met en place des adaptations (aérenchymes, lenticelles hypertrophiées et racines adventives) et exprime davantage QpHb1 que le chêne sessile notamment dans les racines adventives. La régulation spatio-temporelle de QpHb1 pourrait être impliquée dans la capacité de tolérance ainsi que dans la cascade de signalisation menant au développement de ces adaptations.

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Ecological determinants of fungal diversity on dead wood in European forests

2 juin 2010

The fine-scale ecological determinants for wood-inhabiting aphyllophoroid basidiomycetes were investigated with statistical analyses of the occurrence of fruit bodies on woody debris collected in Switzerland and Ukraine. Three substrate descriptors were considered: diameter, degree of decomposition and host tree species. By means of Multiple Regression Trees, thresholds in the response of fungal communities to these local environmental descriptors were detected. Three classes for diameter, as well as for degree of decomposition were thus delimited. They revealed the importance of very small sizes, which were not reported in the literature so far: the relevant diameter class limits were about 0.72 cm and 1.35 cm. Within the host tree species, a clear distinction between coniferous and broadleaf species was found. The next splits followed rather climatic determinants of tree distribution than taxonomical entities such as families or genera. The fidelity of the 59 fungal species to diameter classes, decomposition classes and host tree species was measured by the Dufrêne-Legendre index and only significant responses after permutation tests were retained. This brought new insights on the ecology of many wood-inhabiting aphyllophoroid basidiomycetes. Redundancy Analysis was applied to investigate the response of fungal species to diameter and degree of decomposition of woody debris from the most common host tree species, Fagus sylvatica. This direct gradient analysis made it possible to reconstruct the succession of fungal species along the wood decomposition process.

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Les terres rares et les isotopes radiogéniques comme traceurs d’échange et de transfert dans les cycles géochimiques externes

2 juin 2010

Ce mémoire présente une vue d'ensemble de mes travaux de recherche, réalisés depuis 1995 en tant que post-doctorant au Centre de Géochimie de la Surface de Strasbourg et depuis 1998 en tant que Maître de Conférences à l'université de Franche-Comté de Besançon. Dans toutes ces études, je me suis intéressé aux échanges et transferts chimiques dans les cycles géochimiques externes, avec comme principaux outils de traçage les terres rares (TR) et les isotopes radiogéniques du Sr et du Nd.<br /> J'ai suivi une formation classique de géologue-sédimentologue, que j'ai complété au cours de ma thèse, par les outils de traçage de la géochimie élémentaire et isotopique. Le début de mes années post-doctorales marque une rupture avec mes thématiques de recherche antérieures : j'ai abandonné les problématiques de reconstitutions paléogéographiques et paléotectoniques, pour me consacrer entièrement aux processus de transferts et d'échanges chimiques dans les couches géologiques superficielles, en contexte naturel ou anthropisé.<br /> Cette réorientation a commencé par l'étude d'un sol contaminé de la région de Bâle (Suisse), suivi par un projet sur les transferts chimiques dans des gisements de sel, dans le cadre d'études de faisabilité sur le stockage de déchets radioactifs dans des dômes de sel en Allemagne. Elle s'est poursuivie par des études de circulations d'eau de mer dans le récif corallien de Tahiti et en contexte hydrothermal de basse température, sur la plaque des Cocos. Après cette incursion dans le milieu marin, je suis revenu, ces dernières années, en milieu continental avec des projets portant sur le transport des TR dans des ruisseaux du Massif Central et sur le transfert des TR à l'interface géosphère-biosphère sur des sites du Jura, des Vosges et du Kaiserstuhl (volcan inactif près de Freiburg, Allemagne). L'ensemble de ces travaux de recherche a été le fruit de nombreuses collaborations.<br /> Malgré la diversité des objets, nous avons souvent rencontré des mécanismes de transferts et d'échanges chimiques très similaires. L'identification de ces mécanismes était basée sur une utilisation combinée des TR, des isotopes et d'autres outils, tels que les éléments majeurs ou les données minéralogiques. Nous avons ainsi constaté que la mobilité des TR et d'autres métaux traces est le plus souvent liée à la présence et à la stabilité de phases accessoires, telles que l'apatite et des oxyhydroxides Fe-Mn. En ce qui concerne le transport en phase liquide, nos résultats suggèrent une influence importante de la fraction colloïdale et de la végétation. Celles-ci se combinent à d'autres paramètres de contrôle plus "classiques" (pH, Eh, complexes solubles, sorption etc.). C'est la raison pour laquelle, nous souhaitons à l'avenir intégrer d'avantage l'étude du rôle de la phase colloïdale et de la végétation à nos projets de recherche.<br /> Les TR représentent aujourd'hui un outil de traçage particulièrement pertinent dont l'analyse s'est simplifiée. Leur dosage peut, dans la plupart des cas, être intégré à une analyse de routine par ICP-MS, sans générer ni sur-coûts ni complément de travail. Il serait aujourd'hui dommage de ne pas intégrer ces dosages de TR aux analyses chimiques par ICP-MS. Toutefois, les spectres des TR doivent parfois être combinés avec des données isotopiques du Sr et du Nd afin d'écarter toute ambiguïté dans leur interprétation.

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Landscape composition and spatial prediction of alveolar echinococcosis in southern ningxia, china.

2 juin 2010

BACKGROUND: Alveolar echinococcosis (AE) presents a serious public health challenge within China. Mass screening ultrasound surveys can detect pre-symptomatic AE, but targeting areas identified from hospital records is inefficient regarding AE. Prediction of undetected or emerging hotspots would increase detection rates. Voles and lemmings of the subfamily Arvicolinae are important intermediate hosts in sylvatic transmission systems. Their populations reach high densities in productive grasslands where food and cover are abundant. Habitat availability is thought to affect arvicoline population dynamic patterns and definitive host-intermediate host interactions. Arvicoline habitat correlates with AE prevalence in Western Europe and southern Gansu Province, China. METHODS AND FINDINGS: Xiji County, Ningxia Hui Autonomous Region, borders southern Gansu. The aims of this study were to map AE prevalence across Xiji and test arvicoline habitat as a predictor. Land cover was mapped using remotely sensed (Landsat) imagery. Infection status of 3,205 individuals screened in 2002-2003 was related, using generalised additive mixed models, to covariates: gender; farming; ethnicity; dog ownership; water source; and areal cover of mountain pasture and lowland pasture. A Markov random field modelled additional spatial variation and uncertainty. Mountain pasture and lowland pasture were associated with below and above average AE prevalence, respectively. CONCLUSIONS: Low values of the normalised difference vegetation index indicated sub-optimality of lowland pasture for grassland arvicolines. Unlike other known endemic areas, grassland arvicolines probably did not provide the principal reservoir for Echinococcus multilocularis in Xiji. This result is consistent with recent small mammal surveys reporting low arvicoline densities and high densities of hamsters, pikas and jerboas, all suitable intermediate hosts for E. multilocularis, in reforested lowland pasture. The risk of re-emergence is discussed. We recommend extending monitoring to: southern Haiyuan County, where predicted prevalence was high; southern Xiji County, where prediction uncertainty was high; and monitoring small mammal community dynamics and the infection status of dogs.

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Caractérisation et validation du marqueur microsatellite multilocus répété en tandem EmsB pour la recherche de polymorphisme génétique chez Echinococcus multilocularis : application à l’étude de la transmission du parasite en Europe

2 juin 2010

Echinococcus multilocularis est un parasite nécessitant pour survivre un passage successif entre les carnivores, comme le renard et les micro-mammifères. Le parasite est responsable chez l'homme de l'Echinococcose Alvéolaire, une maladie mortelle si elle n'est pas prise en charge. Uniquement décrit dans l'hémisphère nord (Chine, Japon, Europe et Amérique du Nord), la distribution spatiale du parasite semble connaître une évolution récente, notamment en Europe, où l'Arc alpin est décrit comme le foyer historique d'E. multilocularis dans cette région. Le génotypage a été choisi pour étudier la diffusion du parasite en Europe. Cependant, le manque d'outils de détection du polymorphisme du parasite nécessitait la recherche et la caractérisation de marqueurs possédant un haut pouvoir discriminant. Après caractérisation et validation de la cible EmsB multilocus répétée en tandem, la diversité génétique du parasite en Europe a été étudiée à différentes échelles spatiales d'analyse. A l'échelle micro-locale (rongeurs parasités d'une même pâture), les isolats présentaient une faible diversité génétique entre eux, évoquant une contamination des rongeurs par une même source infectieuse (e.g. les fèces d'un même renard parasité). A l'échelle locale (900 km²), 140 parasites de 25 renards ont été étudiés. Les parasites présentaient une diversité génétique permettant de distinguer 6 profils EmsB. La présence simultanée de différents profils chez le renard a été décrite de manière fréquente, évoquant des infestations répétées des renards. Un faible taux d'hétérozygotie a été trouvé chez le parasite, ce qui pourrait être expliqué par un mode de reproduction principalement clonal. A l'échelle continentale (9 sous-régions européennes de la zone endémique historique et de la périphérie de celle-ci) la diversité génétique et la structure spatiale du polymorphisme ont été étudiées à partir de 653 isolats (596 vers adultes isolés de 129 renards, 57 lésions opérés chez des patients et des animaux vivant en captivité). Une grande diversité génétique a été observée en Europe, avec la description de 54 profils EmsB. Des profils transversaux ont été trouvés de part et d'autre de la zone d'étude alors que d'autres plus endémiques étaient limités spatialement. L'étude de la composition génétique au sein des sous-régions européennes a permis de mettre en évidence une plus grande diversité génétique dans le foyer historique par rapport à sa zone périphérique, où quelques profils représentaient la majorité des parasites. Cette distribution évoque une dispersion du parasite à partir de la zone centrale vers la zone périphérique dans un système de transmission « continent-île ». Chez l'homme et l'animal en captivité des profils EmsB décrits comme endémiques ont été trouvés sur plusieurs années, montrant une contamination de manière locale par une même souche. Cette étude constitue la première application d'un marqueur microsatellite multilocus pour l'étude de la circulation d'un helminthe à l'échelle continentale.

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Small-mammal assemblage response to deforestation and afforestation in central China

2 juin 2010

Deforestation is a major environmental issue driving the loss of animal and plant species. Afforestation has recently been promoted to conserve and restore Chinese forest ecosystems. We investigated the distribution of small-mammal assemblages in an area where forest and associated deforestation habitats dominate and in an agricultural area where afforestation is ongoing in the Loess Plateau of southern Ningxia Autonomous Region, P.R. China. Multiple trapping was used. Assemblages were defined based on the multinomial probability distribution and information theory. Species turnover between assemblages of deforested and afforested habitats was high, although no clear effect on species richness was observed. The two assemblages described along the deforestation gradient displayed higher diversity, whereas diversity was lower in assemblages identified in afforested habitats where Cricetulus longicaudatus, known agricultural pest in various areas of China, clearly dominated. The threatened Sorex cylindricauda and Eozapus setchuanus were recorded along the deforestation gradient but not in plantations. Therefore, habitats present along a deforestation succession in this part of Ningxia sustain a high diversity of small mammals and include species of conservation concern. At the present stage of its process (maximum 15 years), afforestation in southern Ningxia favours the dominance of an agricultural pest.

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Analysis of human papillomavirus type 16 (HPV16) DNA load and physical state for identification of HPV16-infected women with high-grade lesions or cervical carcinoma.

25 mai 2010

Integration of human papillomavirus (HPV) DNA into the host cell genome is a frequent event in cervical carcinogenesis, even though this phenomenon does not seem to be mandatory for cervical cancer development. Our objective was to describe the load and physical state of HPV type 16 (HPV16) DNA in a series of cervical samples representative of the natural history of cervical cancer. We used a combination of three real-time PCR assays targeting E6, E2, and albumin genes to calculate HPV16 load (E6 and albumin) and the E2/E6 ratio as a surrogate of integration. This method was applied to 173 HPV16-positive cervical samples. Results show that viral load increases with the lesion grade (from 102 HPV16 DNA copies per 10(3) cells in normal samples up to 56,354 copies per 10(3) cells in cancers), while E2/E6 ratio decreases (from 1 in normal samples down to 0.36 in cancers). We propose that, according to this technique, an HPV16 viral load of higher than 22,000 copies/10(3) cells or an E2/E6 ratio of lower than 0.50 allows the identification of women with prevalent high-grade lesions or worse with a high specificity. In conclusion, both viral load and E2/E6 ratio, used in combination with an appropriate cutoff value, are suitable to screen women with prevalent cervical intraepithelial neoplasia grade 2 or 3 or cancer. Therefore, these assays would be useful in addition to routine HPV testing to more accurately identify women with (pre)cancerous lesions.

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Analysis of human papillomavirus type 16 (HPV16) DNA load and physical state for identification of HPV16-infected women with high-grade lesions or cervical carcinoma.

25 mai 2010

Integration of human papillomavirus (HPV) DNA into the host cell genome is a frequent event in cervical carcinogenesis, even though this phenomenon does not seem to be mandatory for cervical cancer development. Our objective was to describe the load and physical state of HPV type 16 (HPV16) DNA in a series of cervical samples representative of the natural history of cervical cancer. We used a combination of three real-time PCR assays targeting E6, E2, and albumin genes to calculate HPV16 load (E6 and albumin) and the E2/E6 ratio as a surrogate of integration. This method was applied to 173 HPV16-positive cervical samples. Results show that viral load increases with the lesion grade (from 102 HPV16 DNA copies per 10(3) cells in normal samples up to 56,354 copies per 10(3) cells in cancers), while E2/E6 ratio decreases (from 1 in normal samples down to 0.36 in cancers). We propose that, according to this technique, an HPV16 viral load of higher than 22,000 copies/10(3) cells or an E2/E6 ratio of lower than 0.50 allows the identification of women with prevalent high-grade lesions or worse with a high specificity. In conclusion, both viral load and E2/E6 ratio, used in combination with an appropriate cutoff value, are suitable to screen women with prevalent cervical intraepithelial neoplasia grade 2 or 3 or cancer. Therefore, these assays would be useful in addition to routine HPV testing to more accurately identify women with (pre)cancerous lesions.

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Expression of major histocompatibility complex class I chain-related molecule A, NKG2D, and transforming growth factor-beta in the liver of humans with alveolar echinococcosis : new actors in the tolerance to parasites ?

25 mai 2010

BACKGROUND: Echinococcus multilocularis growth and persistent granuloma, which lead to the development of the severe parasitic disease alveolar echinococcosis (AE), might be caused by abnormal expression of stress-induced proteins, with subsequent abnormalities in T cell activation. Similar to its involvement in tumors, the NKG2D-major histocompatability complex class I chain-related molecules A and B (MICA/B) signaling system could be involved in host-parasite interactions; however, its involvement in helminthic diseases has never been studied. METHODS: We studied MICA/B, NKG2D, and transforming growth factor-beta (TGF-beta) expression on liver sections and measured levels of soluble MICA in serum samples obtained from patients with progressive AE. Livers from healthy and cirrhotic subjects were studied as controls. RESULTS: Expression of MICA/B proteins was strongly enhanced in the hepatocytes and endothelial and bile duct cells; in the CD68+ cells of the periparasitic infiltrate, especially epithelioid and giant cells; and, also, in the metacestode germinal layer. Strong expression of MICA/B in the liver contrasted with low numbers of NK cells and lack of expression of NKG2D on the numerous CD8+ T lymphocytes of the periparasitic infiltrate, as well as with the absence of soluble MICA in serum. TGF-beta was strongly expressed by most of the infiltrating lymphocytes. CONCLUSIONS: Sustained expression of MICA/B molecules and TGF-beta might lead to modulation of NKG2D with subsequent inhibition of NKG2D-dependent cytotoxicity. Abnormalities of this signaling system could contribute to parasitic evasion of the host's immunity.

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Expression of major histocompatibility complex class I chain-related molecule A, NKG2D, and transforming growth factor-beta in the liver of humans with alveolar echinococcosis : new actors in the tolerance to parasites ?

25 mai 2010

BACKGROUND: Echinococcus multilocularis growth and persistent granuloma, which lead to the development of the severe parasitic disease alveolar echinococcosis (AE), might be caused by abnormal expression of stress-induced proteins, with subsequent abnormalities in T cell activation. Similar to its involvement in tumors, the NKG2D-major histocompatability complex class I chain-related molecules A and B (MICA/B) signaling system could be involved in host-parasite interactions; however, its involvement in helminthic diseases has never been studied. METHODS: We studied MICA/B, NKG2D, and transforming growth factor-beta (TGF-beta) expression on liver sections and measured levels of soluble MICA in serum samples obtained from patients with progressive AE. Livers from healthy and cirrhotic subjects were studied as controls. RESULTS: Expression of MICA/B proteins was strongly enhanced in the hepatocytes and endothelial and bile duct cells; in the CD68+ cells of the periparasitic infiltrate, especially epithelioid and giant cells; and, also, in the metacestode germinal layer. Strong expression of MICA/B in the liver contrasted with low numbers of NK cells and lack of expression of NKG2D on the numerous CD8+ T lymphocytes of the periparasitic infiltrate, as well as with the absence of soluble MICA in serum. TGF-beta was strongly expressed by most of the infiltrating lymphocytes. CONCLUSIONS: Sustained expression of MICA/B molecules and TGF-beta might lead to modulation of NKG2D with subsequent inhibition of NKG2D-dependent cytotoxicity. Abnormalities of this signaling system could contribute to parasitic evasion of the host's immunity.

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Sel, eau et forêt : hier à aujourd’hui

25 mai 2010

Depuis huit millénaires au moins, les sociétés agricoles ont considéré le sel comme une source de vie et de richesse dont l'origine s'inscrivait dans les mythes. Les approches croisées des ethnologues, des archéologues, des historiens et des environnementalistes permettent aujourd'hui de renouveler profondément nos connaissances sur l'exploitation généralisée de l'eau de mer, des sources salées, des terres salées et du sel gemme. Ainsi, d'extraordinaires techniques ont été mises en oeuvre, tandis que les logiques sociales plaçaient le sel au centre des systèmes de croyance, un peu partout dans le monde. Les vingt-quatre contributions regroupées dans cet ouvrage ont été présentées en octobre 2006 lors d'un colloque international du bicentenaire de la mort de Claude Nicolas Ledoux, l'architecte génial de la Saline Royale d'Arc-et-Senans. Rompant avec les limites entre disciplines scientifiques et les cloisonnements géographiques, les auteurs proposent une nouvelle lecture de l'exploitation du sel en abordant la longue durée, depuis la Chine et le Mexique préhispanique jusqu'à l'Europe préhistorique, ou encore des salines médiévales continentales au sel antique méditerranéen. C'est donc d'histoire technique et sociale qu'il s'agit, en relation avec les modifications environnementales. Olivier Weller, Alexa Dufraisse et Pierre Pétrequin sont tous trois chercheurs au CNRS. Ils s'intéressent respectivement à l'archéologie du sel, à l'histoire des combustibles ligneux et aux sociétés du Néolithique.

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Sel, eau et forêt : hier à aujourd’hui

25 mai 2010

Depuis huit millénaires au moins, les sociétés agricoles ont considéré le sel comme une source de vie et de richesse dont l'origine s'inscrivait dans les mythes. Les approches croisées des ethnologues, des archéologues, des historiens et des environnementalistes permettent aujourd'hui de renouveler profondément nos connaissances sur l'exploitation généralisée de l'eau de mer, des sources salées, des terres salées et du sel gemme. Ainsi, d'extraordinaires techniques ont été mises en oeuvre, tandis que les logiques sociales plaçaient le sel au centre des systèmes de croyance, un peu partout dans le monde. Les vingt-quatre contributions regroupées dans cet ouvrage ont été présentées en octobre 2006 lors d'un colloque international du bicentenaire de la mort de Claude Nicolas Ledoux, l'architecte génial de la Saline Royale d'Arc-et-Senans. Rompant avec les limites entre disciplines scientifiques et les cloisonnements géographiques, les auteurs proposent une nouvelle lecture de l'exploitation du sel en abordant la longue durée, depuis la Chine et le Mexique préhispanique jusqu'à l'Europe préhistorique, ou encore des salines médiévales continentales au sel antique méditerranéen. C'est donc d'histoire technique et sociale qu'il s'agit, en relation avec les modifications environnementales. Olivier Weller, Alexa Dufraisse et Pierre Pétrequin sont tous trois chercheurs au CNRS. Ils s'intéressent respectivement à l'archéologie du sel, à l'histoire des combustibles ligneux et aux sociétés du Néolithique.

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Summer phytoplankton pigments and community composition related to water mass properties in the Gulf of Gabes

22 mai 2010

Variations in phytoplankton pigments and community composition were examined in the Gulf of Gabes in relationship to water mass properties, characterised by the influence of the Modified Atlantic Water and by the thermal stratification. Data were collected on board the R/V Hannibal during July 2005. Distinct water masses were identified using cluster analysis of temperatureesalinity (TeS ) characteristics. Three major clusters appeared based on the combined effects of temperature and salinity. The first cluster was identified as the cool and less salty bottom Modified Atlantic Water (MAW). The warmer and saltier Mediterranean Mixed Water (MMW) represented the second cluster. The third cluster was the Transition Water (TW) separating the two previous clusters. The pigment and taxonomic composition of these water masses were examined. Chlorophyll a was rather low (<200 ng l1). Chlorophyll b was generally the most abundant accessory pigment and fucoxanthin dominated the accessory pigments in the MAW. Proportions of chlorophyll a associated with different phytoplankton classes were estimated using CHEMTAX software, and did not present significant variations among water groups. The results pointed out variations in the relative contribution of each phytoplankton taxa in each station group. Chlorophytes and prasinophytes accounted for 65% of chlorophyll a in the MMW. Diatoms and chlorophytes were relatively abundant in the MAW contributing to almost 63% of chlorophyll a. An unstructured community, slightly dominated by prasinophytes, chlorophytes and cryptophytes, characterised the TW. Different trophic statuses were observed in these water masses, the MMWand the MAWbeing characterised by mesotrophy, while an oligotrophy was observed in the TW. Nutrient availability, particularly the P-limitation supported by the summer stratification, as revealed by the high N:P ratio (greater than 20), seems to enhance the development of small-sized phytoplankton, thereby supporting the regenerated production.

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Summer phytoplankton pigments and community composition related to water mass properties in the Gulf of Gabes

22 mai 2010

Variations in phytoplankton pigments and community composition were examined in the Gulf of Gabes in relationship to water mass properties, characterised by the influence of the Modified Atlantic Water and by the thermal stratification. Data were collected on board the R/V Hannibal during July 2005. Distinct water masses were identified using cluster analysis of temperatureesalinity (TeS ) characteristics. Three major clusters appeared based on the combined effects of temperature and salinity. The first cluster was identified as the cool and less salty bottom Modified Atlantic Water (MAW). The warmer and saltier Mediterranean Mixed Water (MMW) represented the second cluster. The third cluster was the Transition Water (TW) separating the two previous clusters. The pigment and taxonomic composition of these water masses were examined. Chlorophyll a was rather low (<200 ng l1). Chlorophyll b was generally the most abundant accessory pigment and fucoxanthin dominated the accessory pigments in the MAW. Proportions of chlorophyll a associated with different phytoplankton classes were estimated using CHEMTAX software, and did not present significant variations among water groups. The results pointed out variations in the relative contribution of each phytoplankton taxa in each station group. Chlorophytes and prasinophytes accounted for 65% of chlorophyll a in the MMW. Diatoms and chlorophytes were relatively abundant in the MAW contributing to almost 63% of chlorophyll a. An unstructured community, slightly dominated by prasinophytes, chlorophytes and cryptophytes, characterised the TW. Different trophic statuses were observed in these water masses, the MMWand the MAWbeing characterised by mesotrophy, while an oligotrophy was observed in the TW. Nutrient availability, particularly the P-limitation supported by the summer stratification, as revealed by the high N:P ratio (greater than 20), seems to enhance the development of small-sized phytoplankton, thereby supporting the regenerated production.

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Biochemical adaptation of phytoplankton to salinity and nutrient gradients in a coastal solar saltern, Tunisia

22 mai 2010

The distribution of protein and carbohydrate concentrations of the particulate matter (size fraction: 0.45–160 mm) was studied, from 22 January 2003 to 02 December 2003, in three ponds of increasing salinity in the Sfax solar saltern (Tunisia). The coupling of N/P: DIN (DIN ¼ NO2 þ NO3 þ NH4þ) to DIP (DIP¼ PO4 3 ) with P/C: protein/carbohydrates ratios along salinity gradient allowed the discrimination of three types of ecosystems. Pond A1 (mean salinity: 45.0 5.4) having marine characteristics showed enhanced P/C ratios during a diatom bloom. N/P and P/C ratios were closely coupled throughout the sampling period, suggesting that the nutritional status is important in determining the seasonal change in the phytoplankton community in pond A1. In pond A16 (mean salinity: 78.7 8.8), despite the high nitrate load, P/C ratios were overall lower than in pond A1. This may be explained by the fact that dinoflagellates, which were the most abundant phytoplankton in pond A16 might be strict heterotrophs and/or mixotrophs, and so they may have not contributed strongly to anabolic processes. Also, N/P and P/C ratios were uncoupled, suggesting that cells in pond A16 were stressed due to the increased salinity caused by water evaporation, and so cells synthesized reserve products such as carbohydrates. In pond M2 (mean salinity: 189.0 13.8), P/C levels were higher than those recorded in either pond A1 or A16. N/P and P/C were more coupled than in pond A16. Species in the hypersaline pond seemed paradoxally less stressed than in pond A16, suggesting that salt-tolerant extremophile species overcome hypersaline constraints and react metabolically by synthesizing carbohydrates and proteins.

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Biochemical adaptation of phytoplankton to salinity and nutrient gradients in a coastal solar saltern, Tunisia

22 mai 2010

The distribution of protein and carbohydrate concentrations of the particulate matter (size fraction: 0.45–160 mm) was studied, from 22 January 2003 to 02 December 2003, in three ponds of increasing salinity in the Sfax solar saltern (Tunisia). The coupling of N/P: DIN (DIN ¼ NO2 þ NO3 þ NH4þ) to DIP (DIP¼ PO4 3 ) with P/C: protein/carbohydrates ratios along salinity gradient allowed the discrimination of three types of ecosystems. Pond A1 (mean salinity: 45.0 5.4) having marine characteristics showed enhanced P/C ratios during a diatom bloom. N/P and P/C ratios were closely coupled throughout the sampling period, suggesting that the nutritional status is important in determining the seasonal change in the phytoplankton community in pond A1. In pond A16 (mean salinity: 78.7 8.8), despite the high nitrate load, P/C ratios were overall lower than in pond A1. This may be explained by the fact that dinoflagellates, which were the most abundant phytoplankton in pond A16 might be strict heterotrophs and/or mixotrophs, and so they may have not contributed strongly to anabolic processes. Also, N/P and P/C ratios were uncoupled, suggesting that cells in pond A16 were stressed due to the increased salinity caused by water evaporation, and so cells synthesized reserve products such as carbohydrates. In pond M2 (mean salinity: 189.0 13.8), P/C levels were higher than those recorded in either pond A1 or A16. N/P and P/C were more coupled than in pond A16. Species in the hypersaline pond seemed paradoxally less stressed than in pond A16, suggesting that salt-tolerant extremophile species overcome hypersaline constraints and react metabolically by synthesizing carbohydrates and proteins.

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Dynamics of dinoflagellates and environmental factors during the summer in the Gulf of Gabes (Tunisia, Eastern Mediterranean Sea)

21 mai 2010

The summer spatial distribution of the dinoflagellate community along an open coastal sea gradient in the Gulf of Gabes (Tunisia, Eastern Mediterranean Sea), together with environmental factors, were studied. The most dominant families were represented by Gymnodiniaceae (32%), Peridiniaceae (20%), Prorocentraceae (15%), Ceratiaceae (13%) and Ebriaceae (10%). The dinoflagellate community was spatially more concentrated along the coast of the gulf than in the open sea. Eight toxic dinoflagellates were recorded, including Karenia cf. selliformis (37% of total toxic dinoflagellates) which was evenly distributed in both the neritic and open sea areas. Dinocysts contributed 33% of the total motile cells and were more abundant along the coast than in the open sea. This high concentration may be ascribed to nitrogen inputs in the coastal waters of Gabes. The Modified Atlantic Water governed dinoflagellate development in the open sea. The degradation of the water quality due to eutrophication in the Gulf of Gabes may have significant socioeconomic consequences. We suggest that a management framework, similar to that used in freshwater ecosystems, should be developed for the Gulf coast in order to drastically reduce urban interferences.

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Dynamics of dinoflagellates and environmental factors during the summer in the Gulf of Gabes (Tunisia, Eastern Mediterranean Sea)

21 mai 2010

The summer spatial distribution of the dinoflagellate community along an open coastal sea gradient in the Gulf of Gabes (Tunisia, Eastern Mediterranean Sea), together with environmental factors, were studied. The most dominant families were represented by Gymnodiniaceae (32%), Peridiniaceae (20%), Prorocentraceae (15%), Ceratiaceae (13%) and Ebriaceae (10%). The dinoflagellate community was spatially more concentrated along the coast of the gulf than in the open sea. Eight toxic dinoflagellates were recorded, including Karenia cf. selliformis (37% of total toxic dinoflagellates) which was evenly distributed in both the neritic and open sea areas. Dinocysts contributed 33% of the total motile cells and were more abundant along the coast than in the open sea. This high concentration may be ascribed to nitrogen inputs in the coastal waters of Gabes. The Modified Atlantic Water governed dinoflagellate development in the open sea. The degradation of the water quality due to eutrophication in the Gulf of Gabes may have significant socioeconomic consequences. We suggest that a management framework, similar to that used in freshwater ecosystems, should be developed for the Gulf coast in order to drastically reduce urban interferences.

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Abundance and biomass of prokaryotic and eukaryotic microorganisms coupled with environmental factors in an arid multi-pond solar saltern (Sfax, Tunisia)

20 mai 2010

The distribution of abundance and biomass of prokaryotes, flagellates, ciliates and phytoplankton, were studied in five ponds of increasing salinity in the Sfax solar saltern (Tunisia) coupled with environmental factors. The results showed that abundance of eukaryotic microorganisms decreased with increasing salinity of the ponds whereas prokaryotes (heterotrophic bacteria and Archaea) were abundant in the hyper-saline ponds. Phototrophic picoplankton was found in a large range of salinity values (70 and 200‰). Phototrophic non-flagellated nanoplankton which dominated in the first sampled pond was substituted by phototrophic flagellated nanoplankton in the other ponds. Heterotrophic nanoplankton dominated in the crystallizer pond but its quantitative importance declined in the less saline ponds. Diatoms and dinoflagellates were the major contributors to phytoplankton abundance in the first ponds (.90% of total abundance). Ciliated protozoa were found in all the ponds except in the crystallizer in which prokaryotes proliferated. Oligotrichida and Heterotrichida were the most abundant ciliate groups. Overall, species richness decreased with salinity gradient. We propose a simplified diagram of the Sfax saltern's food web showing the dominant role of the microbial loop along the salinity gradient.

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Abundance and biomass of prokaryotic and eukaryotic microorganisms coupled with environmental factors in an arid multi-pond solar saltern (Sfax, Tunisia)

20 mai 2010

The distribution of abundance and biomass of prokaryotes, flagellates, ciliates and phytoplankton, were studied in five ponds of increasing salinity in the Sfax solar saltern (Tunisia) coupled with environmental factors. The results showed that abundance of eukaryotic microorganisms decreased with increasing salinity of the ponds whereas prokaryotes (heterotrophic bacteria and Archaea) were abundant in the hyper-saline ponds. Phototrophic picoplankton was found in a large range of salinity values (70 and 200‰). Phototrophic non-flagellated nanoplankton which dominated in the first sampled pond was substituted by phototrophic flagellated nanoplankton in the other ponds. Heterotrophic nanoplankton dominated in the crystallizer pond but its quantitative importance declined in the less saline ponds. Diatoms and dinoflagellates were the major contributors to phytoplankton abundance in the first ponds (.90% of total abundance). Ciliated protozoa were found in all the ponds except in the crystallizer in which prokaryotes proliferated. Oligotrichida and Heterotrichida were the most abundant ciliate groups. Overall, species richness decreased with salinity gradient. We propose a simplified diagram of the Sfax saltern's food web showing the dominant role of the microbial loop along the salinity gradient.

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Fatty Acid Composition in Relation to the Micro-organisms in the Sfax Solar Saltern, Tunisia

20 mai 2010

The composition of the fatty acids (FAs) of the particulate matter (size fraction 0.2–100 μm) in five ponds of increasing salinity in the Sfax solar saltern (Tunisia) was studied simultaneously with the abundance of bacteria pico-nano-microphytoplankton and ciliates during the winter of 2006. The FAs analysis was performed by gas chromatography and gas chromatography coupled with mass spectrometry. The potential relationships between FAs and micro-organisms were tested through redundancy analysis (RDA) which allowed to keep all physico-chemical factors constant, including salinity. The results showed a great diversity of FAs from 10 to 24 carbon atoms, which could be saturated, unsaturated, linear or branched. The predominant saturated FAs were 14:0, 16:0 and 18:0, and might originate from diatoms, Dinophyceae and flagellates for the first ponds and from Chlorophyceae, heterotrophic bacteria (HB) in hypersaline ponds. The polyunsaturated fatty acids (PUFAs) (EPA: eicosapentaenoic acid, DHA: docosahexaenoic acid) were detected in small quantities. The branched fatty acids (18:0 12Me or 18:2 12Me) might be attributed primarily to bacteria and archea. Species richness and abundance of aquatic microorganisms decreased as the salt concentration increased, while dominant FAs profiles were overall similar along the salinity gradient

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Fatty Acid Composition in Relation to the Micro-organisms in the Sfax Solar Saltern, Tunisia

20 mai 2010

The composition of the fatty acids (FAs) of the particulate matter (size fraction 0.2–100 μm) in five ponds of increasing salinity in the Sfax solar saltern (Tunisia) was studied simultaneously with the abundance of bacteria pico-nano-microphytoplankton and ciliates during the winter of 2006. The FAs analysis was performed by gas chromatography and gas chromatography coupled with mass spectrometry. The potential relationships between FAs and micro-organisms were tested through redundancy analysis (RDA) which allowed to keep all physico-chemical factors constant, including salinity. The results showed a great diversity of FAs from 10 to 24 carbon atoms, which could be saturated, unsaturated, linear or branched. The predominant saturated FAs were 14:0, 16:0 and 18:0, and might originate from diatoms, Dinophyceae and flagellates for the first ponds and from Chlorophyceae, heterotrophic bacteria (HB) in hypersaline ponds. The polyunsaturated fatty acids (PUFAs) (EPA: eicosapentaenoic acid, DHA: docosahexaenoic acid) were detected in small quantities. The branched fatty acids (18:0 12Me or 18:2 12Me) might be attributed primarily to bacteria and archea. Species richness and abundance of aquatic microorganisms decreased as the salt concentration increased, while dominant FAs profiles were overall similar along the salinity gradient

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Expression of major histocompatibility complex class I chain-related molecule A, NKG2D, and transforming growth factor-beta in the liver of humans with alveolar echinococcosis : new actors in the tolerance to parasites ?

17 mai 2010

BACKGROUND: Echinococcus multilocularis growth and persistent granuloma, which lead to the development of the severe parasitic disease alveolar echinococcosis (AE), might be caused by abnormal expression of stress-induced proteins, with subsequent abnormalities in T cell activation. Similar to its involvement in tumors, the NKG2D-major histocompatability complex class I chain-related molecules A and B (MICA/B) signaling system could be involved in host-parasite interactions; however, its involvement in helminthic diseases has never been studied. METHODS: We studied MICA/B, NKG2D, and transforming growth factor-beta (TGF-beta) expression on liver sections and measured levels of soluble MICA in serum samples obtained from patients with progressive AE. Livers from healthy and cirrhotic subjects were studied as controls. RESULTS: Expression of MICA/B proteins was strongly enhanced in the hepatocytes and endothelial and bile duct cells; in the CD68+ cells of the periparasitic infiltrate, especially epithelioid and giant cells; and, also, in the metacestode germinal layer. Strong expression of MICA/B in the liver contrasted with low numbers of NK cells and lack of expression of NKG2D on the numerous CD8+ T lymphocytes of the periparasitic infiltrate, as well as with the absence of soluble MICA in serum. TGF-beta was strongly expressed by most of the infiltrating lymphocytes. CONCLUSIONS: Sustained expression of MICA/B molecules and TGF-beta might lead to modulation of NKG2D with subsequent inhibition of NKG2D-dependent cytotoxicity. Abnormalities of this signaling system could contribute to parasitic evasion of the host's immunity.

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Expression of major histocompatibility complex class I chain-related molecule A, NKG2D, and transforming growth factor-beta in the liver of humans with alveolar echinococcosis : new actors in the tolerance to parasites ?

17 mai 2010

BACKGROUND: Echinococcus multilocularis growth and persistent granuloma, which lead to the development of the severe parasitic disease alveolar echinococcosis (AE), might be caused by abnormal expression of stress-induced proteins, with subsequent abnormalities in T cell activation. Similar to its involvement in tumors, the NKG2D-major histocompatability complex class I chain-related molecules A and B (MICA/B) signaling system could be involved in host-parasite interactions; however, its involvement in helminthic diseases has never been studied. METHODS: We studied MICA/B, NKG2D, and transforming growth factor-beta (TGF-beta) expression on liver sections and measured levels of soluble MICA in serum samples obtained from patients with progressive AE. Livers from healthy and cirrhotic subjects were studied as controls. RESULTS: Expression of MICA/B proteins was strongly enhanced in the hepatocytes and endothelial and bile duct cells; in the CD68+ cells of the periparasitic infiltrate, especially epithelioid and giant cells; and, also, in the metacestode germinal layer. Strong expression of MICA/B in the liver contrasted with low numbers of NK cells and lack of expression of NKG2D on the numerous CD8+ T lymphocytes of the periparasitic infiltrate, as well as with the absence of soluble MICA in serum. TGF-beta was strongly expressed by most of the infiltrating lymphocytes. CONCLUSIONS: Sustained expression of MICA/B molecules and TGF-beta might lead to modulation of NKG2D with subsequent inhibition of NKG2D-dependent cytotoxicity. Abnormalities of this signaling system could contribute to parasitic evasion of the host's immunity.

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[Treatment of alveolar echinococcosis : a multidisciplinary task]

17 mai 2010

Alveolar echinococcosis is characterized by a long asymptomatic period but, without treatment, up to 80% of patients may die within ten years of diagnosis. Owing to a lack of fast-acting and fully effective chemotherapy, partial radical hepatic resection is the only chance of cure. One-third of patients are now treated in this way, and complex vascular and biliary reconstruction procedures are sometimes necessary. Liver transplantation may also be indicated for highly selected patients (about 5%) with life-threatening complications after failure of other treatments. Interventional radiology and endoscopy can be used to drain liver abscesses and/or infected and obstructed bile ducts, either as palliative procedures or as a bridge to radical resection. Parasitostatic benzimidazole therapy, especially based on continuous albendazole administration, is mandatory for at least two years after radical resection, and for life in inoperable patients.

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[Treatment of alveolar echinococcosis : a multidisciplinary task]

17 mai 2010

Alveolar echinococcosis is characterized by a long asymptomatic period but, without treatment, up to 80% of patients may die within ten years of diagnosis. Owing to a lack of fast-acting and fully effective chemotherapy, partial radical hepatic resection is the only chance of cure. One-third of patients are now treated in this way, and complex vascular and biliary reconstruction procedures are sometimes necessary. Liver transplantation may also be indicated for highly selected patients (about 5%) with life-threatening complications after failure of other treatments. Interventional radiology and endoscopy can be used to drain liver abscesses and/or infected and obstructed bile ducts, either as palliative procedures or as a bridge to radical resection. Parasitostatic benzimidazole therapy, especially based on continuous albendazole administration, is mandatory for at least two years after radical resection, and for life in inoperable patients.

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Analyses et dynamiques spatiales autour des sources salées de Moldavie précarpatique durant la Préhistoire roumaine (6000-3500 BC)

12 mai 2010

Débuté fin 2003, ce programme interdisciplinaire franco-roumain s'intéresse aux dynamiques et aux interactions dans la longue durée entre l'Homme et une ressource particulière de Moldavie sous-carpatique : l'eau des sources salées. Ce projet regroupant archéologue, historien, ethnologue, géomaticien, géoarchéologue, chimiste et environnementaliste fut présenté lors du colloque de Piatra Neamt (Roumanie) en 2004. En choisissant d'utiliser un outil d'analyse spatiale performant comme le SIG, de multiplier les relevés GPS et les prospections de terrain et d'affiner au mieux les inventaires de sites archéologiques comme de sources salées, nous avons pu élaborer une base de données documentaire fournie et géoréférencée (établissements archéologiques et sources salées du département du Neamt), mais aussi intégrer une série de cartes topographiques, géologiques, d'images satellitaires et 2 modèles numériques de terrain sur l'ensemble de la zone d'étude. Nous insisterons ici tout particulièrement sur les premiers résultats obtenus par les analyses statistiques et spatiales sur les dynamiques d'occupation de l'espace observées pour le département du Neamt durant le Néolithique et le Chalcolithique (entre 6000 et 3500 avant J.-C) pour lesquels 241 sites préhistoriques et 59 sources salées ont été enregistrés.

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Analyses et dynamiques spatiales autour des sources salées de Moldavie précarpatique durant la Préhistoire roumaine (6000-3500 BC)

12 mai 2010

Débuté fin 2003, ce programme interdisciplinaire franco-roumain s'intéresse aux dynamiques et aux interactions dans la longue durée entre l'Homme et une ressource particulière de Moldavie sous-carpatique : l'eau des sources salées. Ce projet regroupant archéologue, historien, ethnologue, géomaticien, géoarchéologue, chimiste et environnementaliste fut présenté lors du colloque de Piatra Neamt (Roumanie) en 2004. En choisissant d'utiliser un outil d'analyse spatiale performant comme le SIG, de multiplier les relevés GPS et les prospections de terrain et d'affiner au mieux les inventaires de sites archéologiques comme de sources salées, nous avons pu élaborer une base de données documentaire fournie et géoréférencée (établissements archéologiques et sources salées du département du Neamt), mais aussi intégrer une série de cartes topographiques, géologiques, d'images satellitaires et 2 modèles numériques de terrain sur l'ensemble de la zone d'étude. Nous insisterons ici tout particulièrement sur les premiers résultats obtenus par les analyses statistiques et spatiales sur les dynamiques d'occupation de l'espace observées pour le département du Neamt durant le Néolithique et le Chalcolithique (entre 6000 et 3500 avant J.-C) pour lesquels 241 sites préhistoriques et 59 sources salées ont été enregistrés.

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Settlement pattern and hierarchy :methods and comparison in Languedoc (France) and Istria (Slovenia)

12 mai 2010

Final post-doc report of Saso Poglajen (LEA ModeLTER/Charles Nodier scholarship MAE) The aim the research was to test if there is possibility to compare a good quality settlement distribution data with the pore quality data. The case studies were Languedoc1 in France with good data and north-western Istria (Croatia, Italy and Slovenia) with bad quality data.

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Lidor. Acquisition, traitement et analyse d’images LiDAR pour la modélisation des paléo-reliefs de la plaine littorale du Languedoc oriental.

12 mai 2010

Rapport final du programme ATIP LidOR. Acquisition et traitement de données Lidar acquises en décembre 2006 dans la plaine littorale de Mauguio. L'ensemble des données Lidar acquises a pu être traité pour produire un premier Modèle Numérique de Terrain puis de Surface à 50 cm de résolution qui ont permis une exploration visuelle des données. D'un point de vue thématique, le travail de l'équipe s'est concentré sur le traitement des données avec trois objectifs principaux : la détection des aménagements de la plaine (irrigation, drainage...) depuis l'Antiquité ; la mise en évidence du réseau hydrographique " naturel " avant le détournement artificiel des cours d'eau et l'assèchement des dépressions humides ; la détection des microreliefs résiduels.

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Paleoenvironmental changes during sapropel 19 (i-cycle 90) deposition : evidences from geochemical, mineralogical and micropaleontological proxies in the mid-Pleistocene Montalbano Jonico land section (Southern Italy).

7 mai 2010

An integrated micropaleontological, geochemical and mineralogical study has been performed across the mid-Pleistocene sapropel 19 (i-cycle 90) from the Montalbano Jonico land section (southern Italy), to reconstruct the paleoenvironmental conditions at time of its formation. The sapropel interval is characterized by two oxygen depletion phases (phase A and C) interrupted by a temporary re-oxygenation interval (phase B). The beginning and the end of sapropel deposition are dated at 957±0.81 kyr and 950± 0.86 kyr respectively. The duration of the interruption is estimated to 0.350±0.32 kyr. The multiproxy approach highlights that deposition of sapropel 19 reflects a period of enhanced freshwater runoff induced by a wetter climate. As a consequence of a more efficient fluvial erosion, a higher terrigenous input, mostly ascribable to a southern Apennines source, and an increased turbidity of surface waters accompanied most of sapropel deposition. Biotic and abiotic proxies document that different paleoenvironmental conditions occur through phases A–C. The beginning of phase A is characterized by warm on-land paleoclimate as well as warm and oligotrophic surface water conditions. During the upper part of phase A temperature starts decreasing and surface waters appear more productive. This change probably represents the prelude to cooler and drier conditions characterizing phase B, which displays a river supply reduction and an eolian input increase (Sahara dust). During phase C the restored depleted oxygen environment at the bottom sediments is clearly coupled with the re-establishment of humid conditions and increased river supply. At the same time, enhanced mixing of water column, a cooler paleoclimate, and increased productivity of surface waters are recorded, the latter likely favored by the enhanced mixing of water column and also increased delivery of land-derived nutrients. The end of phase C is marked by a restored “normal” run-off. Enhanced productivity in surface waters and low oxygen conditions at the bottom sediments persist slightly above phase C. The overall results suggest that the onset of sapropel deposition is related to water stratification that caused low oxygen exchanges with the sea-bottom. Although enhanced productivity characterizes most of the sapropel deposition it was not the primary factor triggering sapropel deposition.

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Paleoenvironmental changes during sapropel 19 (i-cycle 90) deposition : evidences from geochemical, mineralogical and micropaleontological proxies in the mid-Pleistocene Montalbano Jonico land section (Southern Italy).

7 mai 2010

An integrated micropaleontological, geochemical and mineralogical study has been performed across the mid-Pleistocene sapropel 19 (i-cycle 90) from the Montalbano Jonico land section (southern Italy), to reconstruct the paleoenvironmental conditions at time of its formation. The sapropel interval is characterized by two oxygen depletion phases (phase A and C) interrupted by a temporary re-oxygenation interval (phase B). The beginning and the end of sapropel deposition are dated at 957±0.81 kyr and 950± 0.86 kyr respectively. The duration of the interruption is estimated to 0.350±0.32 kyr. The multiproxy approach highlights that deposition of sapropel 19 reflects a period of enhanced freshwater runoff induced by a wetter climate. As a consequence of a more efficient fluvial erosion, a higher terrigenous input, mostly ascribable to a southern Apennines source, and an increased turbidity of surface waters accompanied most of sapropel deposition. Biotic and abiotic proxies document that different paleoenvironmental conditions occur through phases A–C. The beginning of phase A is characterized by warm on-land paleoclimate as well as warm and oligotrophic surface water conditions. During the upper part of phase A temperature starts decreasing and surface waters appear more productive. This change probably represents the prelude to cooler and drier conditions characterizing phase B, which displays a river supply reduction and an eolian input increase (Sahara dust). During phase C the restored depleted oxygen environment at the bottom sediments is clearly coupled with the re-establishment of humid conditions and increased river supply. At the same time, enhanced mixing of water column, a cooler paleoclimate, and increased productivity of surface waters are recorded, the latter likely favored by the enhanced mixing of water column and also increased delivery of land-derived nutrients. The end of phase C is marked by a restored “normal” run-off. Enhanced productivity in surface waters and low oxygen conditions at the bottom sediments persist slightly above phase C. The overall results suggest that the onset of sapropel deposition is related to water stratification that caused low oxygen exchanges with the sea-bottom. Although enhanced productivity characterizes most of the sapropel deposition it was not the primary factor triggering sapropel deposition.

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Clay-clast aggregates : a new structural evidence for seismic sliding ?

29 avril 2010

To determine the processes responsible for slip-weakening in clayey gouge zones, rotary-shear experiments were conducted at seismic slip rates (equivalent to 0.9 and 1.3 m/s) at 0.6 MPa normal stress on a natural clayey gouge for saturated and non-saturated initial conditions. The mechanical behavior of the simulated faults shows a reproducible slip-weakening behavior, whatever initial moisture conditions. Examination of gouge obtained at the residual friction stage in saturated and non-saturated initial conditions allows the definition of two types of microstructures: a foliated type reflecting strain localization, and a non-foliated type composed of spherical aggregates. Friction experiments demonstrate that liquid-vapor transition of water within gouge due to frictional heating has a high capacity to explain the formation of spherical aggregates in the first meters of displacement. This result suggests that the occurrence of spherical aggregates in natural clayey fault gouges can constitute a new textural evidence for shallow depth pore water phase transition at seismic slip velocity and consequently for past seismic fault sliding.

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Climate versus human-driven fire regimes in Mediterranean landscapes : the Holocene record of Lago dell’Accesa (Tuscany, Italy)

18 janvier 2010

A high-resolution sedimentary charcoal record from Lago dell'Accesa in southern Tuscany reveals numerous changes in fire regime over the last 11.6 kyr cal. BP and provides one of the longest gap-free series from Italy and the Mediterranean region. Charcoal analyses are coupled with gamma density measurements, organic-content analyses, and pollen counts to provide data about sedimentation and vegetation history. A comparison between fire frequency and lake-level reconstructions from the same site is used to address the centennial variability of fire regimes and its linkage to hydrological processes. Our data reveal strong relationships among climate, fire, vegetation, and land-use and attest to the paramount importance of fire in Mediterranean ecosystems. The mean fire interval (MFI) for the entire Holocene was estimated to be 150 yr, with a minimum around 80 yr and a maximum around 450 yr. Between 11.6 and 3.6 kyr cal. BP, up to eight high-frequency fire phases lasting 300–500 yr generally occurred during shifts towards low lake-level stands (ca 11,300, 10,700, 9500, 8700, 7600, 6200, 5300, 3400, 1800 and 1350 cal. yr BP). Therefore, we assume that most of these shifts were triggered by drier climatic conditions and especially a dry summer season that promoted ignition and biomass burning. At the beginning of the Holocene, high climate seasonality favoured fire expansion in this region, as in many other ecosystems of the northern and southern hemispheres. Human impact affected fire regimes and especially fire frequencies since the Neolithic (ca 8000–4000 cal. yr BP). Burning as a consequence of anthropogenic activities became more frequent after the onset of the Bronze Age (ca 3800–3600 cal. yr BP) and appear to be synchronous with the development of settlements in the region, slash-and-burn agriculture, animal husbandry, and mineral exploitation. The anthropogenic phases with maximum fire activity corresponded to greater sensitivity of the vegetation and triggered significant changes in vegetational communities (e.g. temporal declines of Quercus ilex forests and expansion of shrublands and macchia). The link between fire and climate persisted during the mid- and late Holocene, when human impact on vegetation and the fire regime was high. This finding suggests that climatic conditions were important for fire occurrence even under strongly humanised ecosystem conditions.

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Les aménagements des rives du Doubs à Epomanduodurum. Impact de l’aléa fluvial sur le développement d’une agglomération antique.

18 décembre 2009

L'agglomération antique de Mandeure-Mathay (Epomanduodurum), considérée comme la seconde du pays Séquane par la taille et la parure monumentale, derrière la capitale de cité, Besançon (Marc et al. 2007), fait l'objet d'un Programme Collectif de Recherche depuis 2001. Il vise à une compréhension globale du fonctionnement de la ville et de son espace territorial, suivant une démarche diachronique et pluridisciplinaire. D'un point de vue paléohydrographique quelques grandes questions ont été retenues comme colonne vertébrale du projet scientifique. Suivant quelles modalités l'agglomération du Haut-Empire se développe-t-elle et s'organise-t-elle à l'intérieur de la boucle du Doubs, quelle est la part des facteurs naturels dans cette organisation ? Concernant ces deux aspects de notre recherche, les études conduites depuis 2005 sur le site d'Epomanduodurum, nous ont permis d'acquérir de nouvelles informations sur les dynamiques hydrologiques et sur les relations homme-milieu dans ce secteur de la moyenne vallée du Doubs.

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Rural settlement dynamic during Iron Age in Central Gaul : the excavation and fieldwalking data head to head

4 novembre 2009

La mesure de l'évolution des rythmes de peuplement pose de nombreux problèmes liés, en particulier, à l'hétérogénéité des données disponibles. En s'inspirant des méthodes développées dans l'atelier 2 du projet Archaedyn, nous avons voulu mesurer plus finement ces décalages entre données de prospections et celles issues des fouilles préventives. La confrontation des corpus bourguignons permet d'observer une nette différence de comportement entre les sites fouillés et ceux prospectés, relativisant l'apport d'étude qui ne prendrait pas en compte ces deux modes de collecte.

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Spatial Analysis of Salt Springs Exploitation in Moldavian Pre-Carpatic Prehistory (Romania)

11 septembre 2009

This paper presents the first results of the spatial analysis concerning the dynamics and interaction between settlement patterns from the Neolithic to Chalcolithic times (6000-3500 BC) and a particular mineral resource<br />exploited since the Early Neolithic, the salt springs in the Oriental Carpathian Mountains. Using kernel densities and viewsheds, we propose some natural and anthropological factors which structure this regional territory.

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Risk for non Hodgkin’s lymphoma in the vicinity of French municipal solid waste incinerators.

16 juillet 2009

BACKGROUND: Dioxin emissions from municipal solid waste incinerators are one of the major sources of dioxins and therefore are an exposure source of public concern. There is growing epidemiologic evidence of an increased risk for non-Hodgkin's lymphoma (NHL) in the vicinity of some municipal solid waste incinerators with high dioxin emission levels. The purpose of this study was to examine this association on a larger population scale. METHODS: The study area consisted of four French administrative departments, comprising a total of 2270 block groups. NHL cases that had been diagnosed during the period 1990-1999, and were aged 15 years and over, were considered. Each case was assigned a block group by residential address geocoding. Atmospheric Dispersion Model System software was used to estimate immissions in the surroundings of 13 incinerators which operated in the study area. Then, cumulative ground-level dioxin concentrations were calculated for each block group. Poisson multiple regression models, incorporating penalized regression splines to control for covariates and dealing with Poisson overdispersion, were used. Five confounding factors were considered: population density, urbanisation, socio-economic level, airborne traffic pollution, and industrial pollution. RESULTS: A total of 3974 NHL incident cases was observed (2147 among males, and 1827 among females) during the 1990-1999 time period. A statistically significant relationship was found at the block group level between risk for NHL and dioxin exposure, with a relative risk (RR) of 1.120 (95% confidence interval [CI] 1.002 - 1.251) for persons living in highly exposed census blocks compared to those living in slightly exposed block groups. Population density appeared positively linked both to risk for NHL and dioxin exposure. Subgroup multivariate analyses per gender yielded a significant RR for females only (RR = 1.178, 95% CI 1.013 - 1.369). CONCLUSION: This study, in line with previous results obtained in the vicinity of the incinerator located in Besançon (France), adds further evidence to the link between NHL incidence and exposure to dioxins emitted by municipal solid waste incinerators. However, the findings of this study cannot be extrapolated to current incinerators, which emit lower amounts of pollutants.

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Dioxin emissions from a municipal solid waste incinerator and risk of invasive breast cancer : a population-based case-control study with GIS-derived exposure.

16 juillet 2009

BACKGROUND: To date, few epidemiologic studies have examined the relationship between environmental PCDD/F exposure and breast cancer in human populations. Dioxin emissions from municipal solid waste incinerators (MSWIs) are one of the major sources of environmental dioxins and are therefore an exposure source of public concern. The purpose of this study was to examine the association between dioxins emitted from a polluting MSWI and invasive breast cancer risk among women residing in the area under direct influence of the facility. METHODS: We compared 434 incident cases of invasive breast cancer diagnosed between 1996 and 2002, and 2170 controls randomly selected from the 1999 population census. A validated dispersion model was used as a proxy for dioxin exposure, yielding four exposure categories. The latter were linked to individual places of residence, using Geographic Information System technology. RESULTS: The age distribution at diagnosis for all cases combined showed a bimodal pattern with incidence peaks near 50 and 70 years old. This prompted us to run models separately for women aged 20-59 years, and women aged 60 years or older. Among women younger than 60 years old, no increased or decreased risk was found for any dioxin exposure category. Conversely, women over 60 years old living in the highest exposed zone were 0.31 time less likely (95% confidence interval, 0.08-0.89) to develop invasive breast cancer. CONCLUSION: Before speculating that this decreased risk reflects a dioxin anti-estrogenic activity with greater effect on late-onset acquired breast cancer, some residual confounding must be envisaged.

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Transfert de bromadiolone (appâts/sols – campagnols de prairie – renards) : Etude environnementale de la persistance et mesure indirecte de l’exposition

15 juillet 2009

Depuis les années 50, les rodenticides anticoagulants sont couramment utilisés pour contrôler les populations de rongeurs commensaux et de prairie. De nombreux empoisonnements de la faune non cible sont répertoriés partout dans le monde. En Europe de l'Ouest notamment, la bromadiolone est utilisée de façon intensive dans les champs. Elle est le seul rodenticide autorisé en France pour contrôler les populations de Campagnol terrestre, Arvicola terrestris Sherman. Ces opérations utilisant des appâts grains de blé enterrés dans le sol sont réalisées à de larges échelles et des dizaines voire des centaines d'empoisonnements secondaires de prédateurs, dont le renard, sont répertoriés chaque année. Cette étude propose d'apporter des éléments de compréhension sur les modalités de son transfert à travers les systèmes biologiques complexes considérés dans leur intégralité.<br />Le premier objectif a été d'évaluer la variabilité environnementale de la persistance de la bromadiolone dans les appâts en conditions naturelles. Cette persistance dans les galeries de traitement est courte (demi-vie de 3 à 6 jours) et faiblement influencée par les conditions environnementales (type de sol et conditions climatiques). Cependant, elle augmente considérablement lors du stockage des appâts dans des réserves (27

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Impacts sédimentaires de la présence humaine et des variations climatiques. Exemples d’enregistrements lacustres, fluviatiles et estuariens.

9 juillet 2009

Ce mémoire d'HDR est établi comme « un état des lieux » de mes travaux de recherche autour du thème « sédimentation continentale », et une présentation de mes perspectives de recherche. Il présente un bilan des travaux de recherche réalisés depuis la période post-doctorale. La question centrale est la suivante : quelle est la part relative du climat et de la pression anthropique dans l'érosion du domaine continental ? <br />Le Quaternaire est caractérisé par une oscillation rapide du climat entre des périodes glaciaires et interglaciaires. Depuis peu, l'étude des variations naturelles du climat, particulièrement celui de la période interglaciaire dans laquelle nous vivons, l'Holocène, a connu un regain d'intérêt avec la mise en évidence d'un réchauffement global de la planète dont l'origine est, au moins en partie, anthropique. Afin de pouvoir cerner et modéliser l'impact réel de l'Homme sur le climat, il est indispensable de connaître avec précision les paramètres forçant les variations climatiques naturelles et les effets de ces variations sur l'environnement, et en particulier les enregistrements sédimentaires puisque ceux-ci sont utilisés dans les reconstructions climatiques puis les modélisations du climat. Les bassins versants, de tailles variées, et l'échelle de temps étudiés permettent de suivre à très court, court et moyen terme uniquement l'effet du climat puis la mise en place de la pression anthropique et son impact dans différents contextes sédimentaires. <br />Les lochs, lacs et tourbières sont des sites dans lesquels les enregistrements sédimentaires sont généralement continus depuis le dernier maximum glaciaire (environ 20 000 ans) et souvent caractérisés par une résolution très fine. En revanche, les enregistrements sédimentaires en domaine alluvial et estuarien sont très réduits et fragmentés, mais non dénués d'intérêt. Il s'agit donc nécessairement de conduire une approche pluridisciplinaire. Au sein de cette thématique globale, mes activités de recherche sont centrées sur une approche minéralogique, granulométrique et géochimique de l'impact des variations climatiques et des phases d'anthropisation sur les sédiments. La question de la datation des sédiments est alors cruciale pour corréler entre eux des événements d'impact régional. C'est là qu'intervient la mise en évidence et la caractérisation de niveaux de téphras dont la dispersion régionale est instantanée à l'échelle des temps géologiques.

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Évolution de l’impact environnemental de lixiviats d’ordures ménagères sur les eaux superficielles et souterraines, approche hydrobiologique et hydrogéologique. Site d’étude : décharge d’Étueffont (Territoire de Belfort – France)

1er juillet 2009

L'utilisation couplée de la géophysique, de traçages d'essais, de bilan hydrique, de la géologie, de l'hydrogéologie, et d'analyse statistique sur les données physico-chimiques a permis de mettre en évidence -des infiltrations de lixiviats comprises entre 31 et 43% à travers une interface naturelle shisteuse, et > à 45% à travers une barrière artificielle géomembranaire, -et un impact localisé sur le réseau piézométrique existant. Les lixiviats récoltés sont traités par lagunage naturel. Suite à l'arrêt des dépôts, l'activité de biodégradation diminue et engendre une baisse de la nocivité des lixiviats bruts, modifiant ainsi le fonctionnement hydrobiologique des lagunes. On note une diversification de l'ensemble des composants de la boucle microbienne assurant le recyclage de la matière. La structuration de la pyramide trophique a permis d'atteindre en dernière lagune, un écosystème viable pour la faune piscicole. Les lixiviats traités subissent une seconde épuration naturelle dans le ruisseau récepteur. Une approche bactériologique des lixiviats, des lagunes et des eaux souterraines a permis d'évaluer la survie des bactéries fécales dans ces différents milieux. Cette décharge ne constitue pas une source importante de bactéries fécales. L'étude de ce site où lixiviats de décharge et apports de fosse septique se mélangent confirme le rôle d'Escherichia coli et des Entérocoques comme marqueurs de contamination fécale assez récente. L'aquifère schisteux s'apparente plus à un aquifère fracturé qu'à une zone imperméable, avec une circulation préférentielle le long de fractures qui n'assure pas une filtration et en font un aquifère vulnérable aux contaminations bactériennes.

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