Surface acoustic wave devices as passive buried sensors
20 février 2014
Surface acoustic wave (SAW) devices are currently used as passive remote-controlled sensors for measuring various physical quantities through a wireless link. Among the two main classes of designs-resonator and delay line-the former has the advantage of providing narrow-band spectrum informations and hence appears compatible with an interrogation strategy complying with Industry-Scientific-Medical regulations in radio-frequency (rf) bands centered around 434, 866, or 915 MHz. Delay-line based sensors require larger bandwidths as they consists of a few interdigitated electrodes excited by short rf pulses with large instantaneous energy and short response delays but is compatible with existing equipment such as ground penetrating radar (GPR). We here demonstrate the measurement of temperature using the two configurations, particularly for long term monitoring using sensors buried in soil. Although we have demonstrated long term stability and robustness of packaged resonators and signal to noise ratio compatible with the expected application, the interrogation range (maximum 80 cm) is insufficient for most geology or geophysical purposes. We then focus on the use of delay lines, as the corresponding interrogation method is similar to the one used by GPR which allows for rf penetration distances ranging from a few meters to tens of meters and which operates in the lower rf range, depending on soil water content, permittivity, and conductivity. Assuming propagation losses in a pure dielectric medium with negligible conductivity (snow or ice), an interrogation distance of about 40 m is predicted, which overcomes the observed limits met when using interrogation methods specifically developed for wireless SAW sensors, and could partly comply with the above-mentioned applications. Although quite optimistic, this estimate is consistent with the signal to noise ratio observed during an experimental demonstration of the interrogation of a delay line buried at a depth of 5 m in snow.
Photolysis of Bovine Serum Albumin by near UV irradiation
20 janvier 2014
Proteins are major biological targets for oxidative damage due to their abundance and high rates of reactions with reactive oxygen species including radicals and excited state species. This work studies the photooxidation of Bovine Serum Albumin (BSA) by singlet molecular oxygen (1O2) using Raman spectroscopy which allows the spectral changes induced by oxidation to be directly identified. The results show that these changes mainly affect the S-S and the amide Raman bands. Tri-peptides containing amino acids His, Met, Trp and Tyr whose side chains are known to preferentially react with 1O2 are also analysed allowing the specific changes associated with each amino acid to be observed and discussed within the context of the changes observed in the protein. The singlet oxygen quenching rate constants for BSA were measured using time resolved near infrared phosphorescence. It was found that the rate constants vary as a function of pD thus highlighting the effect of conformation on the process of oxidation.
Plateforme d'apprentissage à distance en radioprotection médicale
25 octobre 2013
Suite à l'initiative développée dans le cadre des LARD et pour répondre aux besoins des milieux professionnels concernés par la radioprotection et la radiophysique médicale, une plateforme de formation à distance nommée CIFOR@D (Centre International de FOrmation à distance en RADioprotection médicale) est actuellement mise en place. Cette plateforme est ouverte à tous les organismes ou établissements intéressés par la formation en ligne aussi bien en tant que " consommateur " que " fournisseur " et est gérée sur le plan technique par l'UFC (université de Franche-Comté). Cette plate-forme s'adressera plus particulièrement à deux types de public : a) des personnels médicaux ou des professionnels appartenant aux organismes de surveillance ou de contrôle souhaitant compléter ou approfondir leur formation initiale, b) des étudiants ou des formations de niveau master appartenant essentiellement aux établissements étrangers (Amérique Latine, Afrique, Asie) ou à des écoles doctorales ne disposant pas de cours dans les disciplines mentionnées
CEFOR@D - Plateforme de formation à distance pour la radioprotection médicale
25 octobre 2013
Nous présentons la plate-forme de formation à distance CEFOR@D, dont le but est répondre aux besoins en formation dans les domaines de la radioprotection et de la radiophysique médicale.
Condensation d'ADN plasmidique par des diamines sur un substrat de graphite HOPG
16 septembre 2013
Ce travail vise à améliorer notre connaissance des effets produits par les électrons de basse énergie (EBEs) sur l'ADN. Parmi les composants radiosensibles, les acides nucléiques demeurent en effet une cible critique des EBEs. Ce type d'étude requiert un bon étalement et un contrôle des dépôts d'ADN plasmidique sur des surfaces conductrices. Nous avons étudié en détails la formation de complexes entre des polyamines et l'ADN plasmidique. Une partie du travail a consistéà caractériser les dépôts réalisés sur des substrats de graphite pyrolytique hautement orienté (HOPG) en employant des diamines pour condenser l'ADN. Nous avons montré que dans les conditions opératoires de cette étude, il est possible de créer des dépôts avec des épaisseurs calibrées, présentant un taux dégâts constant et suffisamment bas pour permettre des études ultérieures en gel d'électrophorèse. Ces dépôts, dont l'épaisseur varie de deux à plusieurs dizaines de nanomètres, ont la propriété remarquable de pouvoir être re-dissous dans l'eau sans qu'ils ne subissent de dommages supplémentaires. Les dépôts réalisés avec le diaminopropane ont été exposés aux EBEs et une première exploitation par désorption stimulée (ESD) et par relaxation de plasmide a été effectuée. Ces premiers résultats ouvrent de larges perspectives pour l'utilisation ultérieure des dépôts créés durant ce travail.
Neutral Products Desorption from DNA Thin Films Induced by Low-Energy Electrons (0.5-20 eV)
16 septembre 2013
Low-energy electrons (LEEs) are produced in great amount in the biological medium, when submitted to high-energy radiations. They have the ability to induce strand breaks in the DNA duplex, as proven by electrophoresis analysis of irradiated dry deposits. LEE interactions with target molecules induce the formation of different species such as anions, cations, radicals and neutrals. The desorption of anionic species from oligonucleotides and DNA under LEEs irradiation has been intensively explored. The involved mechanisms and sites were successfully identified, including the resonant formation of transient negative ions (TNI) below 15 eV. However, the desorption of neutral products was less explored [4], due to their difficult detection. Exploring this aspect will provide additional information and complete the picture of the dissociating pathways followed by TNIs.
L'homme et la forêt dans la Haute-Vallée du Doubs à la fin du Moyen âge : modalités et paradoxes d'une anthropisation tardive
27 juin 2013
Le fonctionnement de l'écosystème forestier dans la haute vallée du Doubs, attestant le rôle déterminant du climat, permet par l'examen des conséquences des fluctuations climatiques sur une forêt climacique, de connaître la nature de la couverture forestière médiévale. Le milieu forestier que l'homme doit détruire pour s'installer résulte de la conjugaison d'une dynamique naturelle engagée depuis l'ère quaternaire et d'un impact anthropique progressif. Le lent processus de la colonisation depuis les premières traces de fréquentation mésolithique jusqu'au Moyen Âge, se confond avec l'essor des défrichements. L'histoire du peuplement du Haut-Doubs et du recul de la forêt dont le rythme épouse les vicissitudes démographiques dues aux guerres et aux crises du bas Moyen Âge, présente des singularités dans sa chronologie, les modalités des défrichements et la mise en valeur du territoire. Pourtant, cette forêt que l'homme abat reste une ressource nourricière vitale, source de matières premières et réserve énergétique indispensables aux activités quotidiennes et à un artisanat en essor. S'impose alors à l'homme confronté aux conflits d'intérêt liés à l'usage de la forêt, la nécessité de résoudre ce paradoxe qui consiste à devoir à la fois exploiter et détruire. Les mesures restrictives et les réglementations qui s'instaurent révèlent une prise de conscience relative face aux dangers qui menacent un équilibre écologique fragile, et au nouvel impératif de protection. Cette réalité présage des conflits et des problèmes ultérieurs dont l'homme contemporain est encore à chercher les solutions
Structure and Expression Profile of the Phosphate Pht1 Transporter Gene Family in Mycorrhizal Populus trichocarpa
23 mai 2013
Gene networks involved in inorganic phosphate (Pi) acquisition and homeostasis in woody perennial species able to form mycorrhizal symbioses are poorly known. Here, we describe the features of the 12 genes coding for Pi transporters of the Pht1 family in poplar (Populus trichocarpa). Individual Pht1 transporters play distinct roles in acquiring and translocating Pi in different tissues of mycorrhizal and nonmycorrhizal poplar during different growth conditions and developmental stages. Pi starvation triggered the up-regulation of most members of the Pht1 family, especially PtPT9 and PtPT11. PtPT9 and PtPT12 showed a striking up-regulation in ectomycorrhizas and endomycorrhizas, whereas PtPT1 and PtPT11 were strongly down-regulated. PtPT10 transcripts were highly abundant in arbuscular mycorrhiza (AM) roots only. PtPT8 and PtPT10 are phylogenetically associated to the AM-inducible Pht1 subfamily I. The analysis of promoter sequences revealed conserved motifs similar to other AM-inducible orthologs in PtPT10 only. To gain more insight into gene regulatory mechanisms governing the AM symbiosis in woody plant species, the activation of the poplar PtPT10 promoter was investigated and detected in AM of potato (Solanum tuberosum) roots. These results indicated that the regulation of AM-inducible Pi transporter genes is conserved between perennial woody and herbaceous plant species. Moreover, poplar has developed an alternative Pi uptake pathway distinct from AM plants, allowing ectomycorrhizal poplar to recruit PtPT9 and PtPT12 to cope with limiting Pi concentrations in forest soils.
Eclogite or jadeitite : the two colours involved in the tranfer of alpine axeheads in western Europe
22 mai 2013
Fate of Trace Elements during the Combustion of Phytoremediation Wood
6 mai 2013
We investigated the fate of trace elements (TE) in poplar wood on the conversion of biomass to heat in a 0.2 MW combustion unit equipped with a fabric filter. The phytoremediation wood was harvested from a TE-contaminated agricultural site planted with a high-density poplar stand. The combustion technology used in the present experiment allows for an efficient separation of the various ash fractions. The combustion process concentrates Cu, Cr, and Ni in the bottom ash, heat exchanger ash, and cyclone ash fractions. Therefore, the impact of the fabric filter is negligible for these elements. Conversely, Cd, Pb, and Zn are significantly recovered in the emission fraction in the absence of the fabric filter above the emission limits. The use of a fabric filter will allow the concentration of these three TEs in the ashes collected below the filter, thus complying with all regulatory thresholds, i.e., those from the large combustion plant EU directive. Because the TE concentrations in the different fractions differed significantly, it is recommended that these fractions be treated separately, especially when recycling of ashes from phytoremediation wood through application in agriculture is envisaged
Caractérisation de la structure génétique spatiale des populations de petits rhinolophes en Franche-Comté
19 avril 2013
Mandeure - Impact de l'aléa fluvial sur le développement de l'agglomération antique
15 avril 2013
Le Projet Collectif de Recherche consacréà l'approche pluridisciplinaire de l'agglomération antique d'Epomanduodurum vise à une compréhension globale du fonctionnement de la ville et de son espace territorial. À ce titre, deux questions touchant au domaine de la paléohydrographie avaient été retenues. Suivant quelles modalités l'agglomération du Haut-Empire se développe-telle et s'organise-t-elle à l'intérieur de la boucle du Doubs ? Quelle est la part des facteurs naturels dans cette organisation ? Les études conduites depuis 2001 dans ce secteur de la moyenne vallée du Doubs nous ont permis de mieux documenter ces deux aspects de la recherche, grâce en particulier à l'acquisition d'informations nouvelles sur les dynamiques hydrologiques holocènes et sur les interactions entre l'homme et le milieu.
Impact d'un réchauffement climatique sur le fonctionnement de la sphagnosphère : relations polyphenols-communautés microbiennes
20 mars 2013
Dans un contexte de réchauffement climatique, la fonction puits de carbone des tourbières à sphaignes est susceptible d'être altérée en raison d'une modification des interactions sphaignes-microorganismes, responsables de l'accumulation de carbone. L'objectif de cette thèse a été (1) d'identifier les interactions chimiques entre les polyphénols des sphaignes et les communautés microbiennes des sphaignes et (2) d'évaluer l'impact du réchauffement climatique sur ces relations.Un dispositif expérimental (Open Top Chambers) simulant in situ une hausse modérée des températures (+ 1°C) a été installé sur la tourbière de Frasne (25). La hausse des températures a provoqué une modification du réseau alimentaire microbien avec l'augmentation de la biomasse des bactéries et une baisse importante (-70%) de la biomasse des prédateurs (amibes à thèque). Le réchauffement climatique a également induit une baisse de la production de polyphénols, diminuant ainsi leur effet inhibiteur sur les microorganismes. En parallèle à cette baisse, une hausse des activités enzymatiques phénoloxydases a également été enregistrée. Le réchauffement a ainsi modifié les relations polyphénols - phénoloxydases, deux éléments essentiels du cycle du carbone des tourbières.Les différents changements induits par le réchauffement climatique (polyphénols, phénoloxydases, réseau trophique microbien) ont aussi conduit à une modification des relations " sphaignes-microorganismes " via une accélération potentielle du recyclage des nutriments, ce qui pourrait influencer sur le long terme le fonctionnement de l'écosystème tourbière.
Contamination atmosphérique par les hydrocarbures aromatiques polycycliques : toxicité et devenir du phénanthrène dans des systèmes sol-plante-microorganismes
13 mars 2013
Les hydrocarbures aromatiques polycycliques (HAP) sont des polluants organiques persistants potentiellement mutagènes et cancérigènes. Leur transfert de l'atmosphère vers les écosystèmes, notamment vers les plantes, conditionne leur entrée dans les chaines alimentaires mais les modalités de ce transfert restent encore mal connues. L'objectif de ce travail était donc de caractériser le transfert et d'identifier les effets biologiques des HAP atmosphériques sur un système sol-plante-microorganismes symbiotiques.Un dispositif expérimental a été conçu afin de recréer en laboratoire une pollution atmosphérique par les HAP avec comme HAP modèle le phénanthrène (PHE). Le dispositif a fait l'objet d'une validation et d'une calibration élaborée de manière originale par une double approche mêlant l'expérimental à la simulation mathématique. Les niveaux d'exposition en polluant (150 µg m-3), contrôlés par des échantillonneurs passifs, se sont avérés pertinents par rapport aux conditions in situ. Ce dispositif a donc été utilisé pour exposer durant un mois des microsystèmes sol-plante-microorganismes au PHE par voie atmosphérique.Les différentes études ont mis en évidence un transfert du PHE depuis l'atmosphère vers tous les compartiments du microsystème, avec une accumulation majeure vers les feuilles de trèfle ou de ray-grass (respectivement 170 et 70 µg g־¹MS) et un transfert phloémien vers les racines est suggéré. Chez le trèfle, la mycorhization n'a pas été affectée, tandis que le nombre de nodules actifs a diminué de manière significative. Contrairement aux racines, la biomasse aérienne du trèfle a été significativement affectée (environ - 25%) par l'exposition au PHE atmosphérique, suggérant un impact sur le métabolisme carboné de la plante. Une expérience de marquage des trèfles au ¹³C-CO2 a effectivement montré un impact négatif du PHE atmosphérique sur la croissance, l'allocation de biomasse et l'allocation carbonée. Pour conclure, ces études ont permis non seulement de caractériser les effets biologiques et physiologiques des HAP atmosphériques sur les végétaux mais également de proposer l'utilisation du potentiel mycorhizien comme indicateur de pollution atmosphérique par les HAP.
Besançon et environs (25), Prospection et validation de données LiDAR, rapport 2011
10 janvier 2013
Ce rapport présente les résultats de prospections au sol obtenus au cours de l'année 2011 sur une partie des 32 communes concernées par un relevé LiDAR effectué au printemps 2009 autour de Besançon. Les prospections qui ont été réalisées ont pour particularité d'être directement liées à des programmes de recherches en archéologie au sein de la MSHE C.N. Ledoux USR 3124 (Anthropisation d'un milieu forestier, la forêt de Chailluz, Besançon ; Construction Historique des Espaces Forestier dans ODIT-Feder) faisant intervenir plusieurs partenaires (CNRS, Université de Franche-Comté, ONF, Ville de Besançon, SRA Franche-Comté, associations Aresac et Avalfort). Pour cette raison, les prospections qui ont été menées jusqu'à présent et dont il est rendu compte ici sont à considérer comme un point particulier correspondant à une étape d'un travail de recherche à plus large échelle qui concerne à l'heure actuelle des zones d'étude plus étendues et situées autour de Besançon et de Mandeure-Mathay. Pour ces deux zones, une opération d'acquisition de données LiDAR intégralement financée par le conseil régional de Franche-Comté a été réalisée en 2009 (170 km2 pour la zone de Besançon, 100 km2 pour la zone de Mandeure-Mathay) dans le cadre d'un projet de recherche intitulé LIEPPEC (LIdar pour l'Etude des Paysages Passés Et Contemporains) porté par la MSHE C.N. Ledoux USR 3124. Les prospections menées dans les deux fenêtres concernées sont à considérer par rapport à cet aspect original : elles sont initiées en fonction des informations obtenues par le biais des relevés LiDAR et sont réalisées essentiellement en milieu forestier, ce qui leur confère également une originalité ayant nécessité une démarche préalable d'adaptation des méthodes utilisées couramment dans le cadre d'opérations de prospection.
[Follow-up of subjects occupationally exposed to asbestos, what are the objectives, the benefits, and the possible risks?].
30 novembre 2012
The follow-up of workers occupationally exposed to asbestos has two possible beneficial effects: (1) individually, both medical by screening for diseases related to asbestos and social by notification of occupational disease and/or compensation from the indemnity funds for asbestos victims; (2) collectively, by the establishment of epidemiological surveillance (follow-up of cohorts) and evaluation of the impact of follow-up in terms of health benefits and compensation. The respiratory disorders related to asbestos are: cancer (malignant pleural mesothelioma and bronchial carcinoma), asbestos-related pulmonary fibrosis, and pleural disease (plaques, pleural fibrosis and benign pleurisy). In the light of the data currently available and the effectiveness of the tools used, medical and public health benefits of screening for mesothelioma have not been demonstrated. The early diagnosis of primary bronchial carcinoma can theoretically improve the prognosis of the subjects screened, particularly by identification of stage I disease on CT (pulmonary nodules). This is a common finding but there are a large number of false-positives. While we await the results of several international randomised trials, the benefits of a screening programme for bronchial carcinoma in the population at risk have not been demonstrated. There is no effective treatment for asbestosis but this is an independent risk factor for bronchial carcinoma and it is evidence of heavy asbestos exposure. Stopping smoking in subjects suffering from asbestosis will reduce the incidence of bronchial carcinoma. There is no effective treatment for asbestos-related benign pleural diseases but these are markers of exposure. The presence of pleural plaques has not been shown to be an aetiological factor for thoracic cancers. Post-occupational follow-up may involve risks to health, particularly repeated irradiation and invasive diagnostic procedures. It is also necessary to consider the psychological consequences inherent in all screening programmes. In conclusion, post-occupational follow-up might reduce the mortality of lung cancer by screening for localised disease and its incidence by a targeted anti-smoking programme. The theoretical benefits, that have not yet been demonstrated, have to be seen in perspective with the risks to physical and psychological health related to both screening and diagnostic procedures.
Chironomid-based reconstruction of Lateglacial summer temperatures from the Ech palaeolake record (French western Pyrenees)
30 novembre 2012
Chironomid head capsules were extracted and identified in 52 samples along a sediment core retrieved from the Ech palaeololake, (710 m a.s.l. in the west-central Pyrenees). The pollen stratigraphy together with radiocarbon dates provided the basis for the chronology of the record. Since temperature changes were identified as one of the major determining factors for shifts in the Ech chironomid assemblages during the Lateglacial, July air temperatures were tentatively inferred from the chironomid record using a transfer function based on a combined Swiss and Norwegian calibration dataset. The model reconstructed July air temperatures between 10 and 13 °C during the Oldest Dryas, a two step increase in temperatures to 16 and 17.5 °C during the first part of the Interstadial followed by a decrease to 16.5 °C at the end of the Interstadial. The Ech record features three centennial-scale 1.5 °C coolings during the Interstadial. Inferred temperatures decreased to 15-15.5 °C during the Younger Dryas, and reached ca. 17 °C at the beginning of the Holocene. The applicability of the combined Swiss-Norwegian transfer function to the Pyrenean fossil record was substantiated by the good statistics of the inference and the similar distribution of taxa with respect to temperature in the Alps and the Pyrenees. The reliability of the Ech record, including its chronology, was supported by its good concordance with other previously published chironomid-based lateglacial temperature reconstructions from Europe and the NGRIP δ18O record
Sondage archéologique sur l'oppidum du Camp de César à Laudun-l'Ardoise. Étude d'une structure du Haut-Empire réutilisée au cours de l'Antiquité tardive.
17 novembre 2012
Dans le cadre des recherches sur les dynamiques de peuplement dans la basse vallée de la Cèze, le sondage réalisé dans cette structure en bordure orientale de l'oppidum du Camp de César à Laudun-l'Ardoise (Gard), a permis d'établir sa construction au cours du Ier siècle de notre ère et de sa réfection au cours des Ve-VIe siècles. L'abondance de mobilier céramique tardo-républicain, et du Haut-Empire, au sein du bâti ou en stratigraphie, ne permettent pas de dater exclusivement cette structure de l'Antiquité tardive, bien que les couches tardo-antiques directement au contact de l'affleurement rocheux, sont un terminus post quem recevable pour la datation de la réfection du bâtiment. Il semble qu'au cours des Ve-VIe siècles de nouveaux constructeurs ont procédéà des terrassements mettant à jour les maçonneries préexistantes du Ier siècle, qui ont alors été réutilisées.
Reconstructing extreme flood events from high altitude lake sediment records : methodological issues and first results
12 novembre 2012
Apport du lidar à la connaissance de l'histoire de l'occupation du sol en forêt de Haye
12 octobre 2012
Le potentiel archéologique des forêts est fort, notamment en raison de la bonne conservation des vestiges sous forme de micro-reliefs, mais les prospections archéologiques sont gênées par le couvert forestier, ce qui freine l'étude des sites. Une méthode de télédétection assez récente, le scanneur laser aéroporté ou lidar, permet de s'affranchir d'une partie des contraintes physiques et permet le repérage et la cartographie des vestiges. Cette technique a été appliquée au massif forestier de Haye, qui couvre 116 km2, à côté de Nancy, durant l'hiver 2006-2007. Elle a permis des apports considérables par rapport aux méthodes de prospection traditionnelles au sol jusque-là utilisées pour étudier les structures agraires et parcellaires et les habitats antiques qui y sont conservés. Ces apports ont porté sur de nombreux points : nette augmentation du nombre de vestiges découverts, amélioration de la localisation des vestiges initialement cartographiés au topofil et à la boussole ou au GPS, apports morphologiques et chronologiques, etc. Nous avons mis au point une méthode de cartographie et élaboré un référentiel de vestiges archéologiques et de structures morphologiques diverses, adaptés à l'analyse et à l'interprétation des données lidar. Au final, cette technique rend possible un véritable changement d'échelle dans l'étude des sites archéologiques et permet d'esquisser dans ses grandes lignes l'histoire de l'occupation du sol de l'actuel massif forestier de Haye.
Pompeian millstones in France
8 octobre 2012
Pompeian millstones are known by their characteristic shape and size. They consist of an hourglass-shaped (bi-conical) upper stone (catillus) and a conical lower stone (meta). The larger models were driven by animals (hence their name, 'donkey mills') by means of fittings inserted in lugs on opposite sides of the catillus. The inclination of the grinding surfaces is very important. Recent research has proved, contrary to established assumption, that this type of mill was quite common in Narbonese Gaul. In this Roman Province, all of these mills are made of volcanic rock. The source of this volcanic rock is most likely the Italian peninsula, specifically the region of Orvieto. Although this distinctive rock was also used for other types of large (hydraulic?) millstones and small hand-operated rotary querns, it was mainly used for Pompeian millstones. Beyond southern France, no comprehensive survey of this type of mill has yet been conducted. Several are known in Amiens, Lyon, Paris, Troyes, etc. Unlike the finds from southern France, not all are of volcanic rock. Most come from excavations of urban sites. The aim of this study is to provide a first distribution of Pompeian mills across French territory. For this study, the factors taken into account are raw material, chronology, and the context of each find
Les moulins de type Pompéi en France
8 octobre 2012
Caractéristiques par leur forme et leurs dimensions, les meules de type Pompéi sont composées d'un catillus de grande taille en forme de coquetier ou de sablier et d'une meta conique. Ces pièces imposantes étaient mues par traction animale au moyen d'encoches aménagées de part et d'autre de la meule dans sa partie la plus étroite. La pente des surfaces actives est importante. Une récente étude a montré l'importance numérique de ce type de moulins dans la Gaule narbonnaise, alors que leur usage était préalablement considéré comme plutôt limité. Dans cette région, la totalité des éléments recensés sont en roche volcanique, très probablement originaire de la péninsule italienne et notamment de la région d'Orvieto. Ce matériau si caractéristique est connu principalement pour des meules de ce type, mais on trouve aussi dans la même roche des meules de grand format d'un autre type (meules hydrauliques ?) et quelques rares meules manuelles. Au-delà de la partie méridionale de la France, aucun recensement exhaustif de ce type d'outils de mouture n'a pour l'instant été mené. Plusieurs meules pompéiennes sont cependant connues à Amiens, Lyon, Paris, Troyes. Contrairement aux pièces originaires du sud de la France, toutes ne sont pas en roche volcanique. Elles ont essentiellement été découvertes lors de fouilles urbaines. Le but du présent travail est de dresser une première carte des meules de type Pompéi à l'échelle du territoire français. L'inventaire de ce type de meules prendra en compte la matière première, la datation et le contexte de chacune des pièces.
Spatial variability of 137Cs activities in soils from the watershed of the Doubs river : range and main sources of variations
3 octobre 2012
Prenatal animal contact and gene expression of innate immunity receptors at birth are associated with atopic dermatitis.
3 octobre 2012
BACKGROUND: Cross-sectional studies have suggested that prenatal farm exposures might protect against allergic disease and increase the expression of receptors of the innate immune system. However, epidemiologic evidence supporting the association with atopic dermatitis remains inconsistent. OBJECTIVE: To study the association between prenatal farm-related exposures and atopic dermatitis in a prospective study. We further analyzed the association between the expression of innate immune genes at birth and atopic dermatitis. METHODS: A total of 1063 children who participated in a birth cohort study, Protection against Allergy-Study in Rural Environments, were included in this study. Doctor diagnosis of atopic dermatitis was reported by the parents from 1 to 2 years of age by questionnaire. Gene expression of Toll-like receptors (TLRs) and CD14 was assessed in cord blood leukocytes by quantitative PCR. RESULTS: Maternal contact with farm animals and cats during pregnancy had a significantly protective effect on atopic dermatitis in the first 2 years of life. The risk of atopic dermatitis was reduced by more than half among children with mothers having contact with 3 or more farm animal species during pregnancy compared with children with mothers without contact (adjusted odds ratio, 0.43; 95% CI, 0.19-0.97). Elevated expression of TLR5 and TLR9 in cord blood was associated with decreased doctor diagnosis of atopic dermatitis. A significant interaction between polymorphism in TLR2 and prenatal cat exposure was observed in atopic dermatitis. CONCLUSION: Maternal contact with farm animals and cats during pregnancy has a protective effect on the development of atopic dermatitis in early life, which is associated with a lower expression of innate immune receptors at birth.
Une nouvelle approche méthodologique pour mesurer le nombre d'opportunités d'Hygiène des mains en unités d'hospitalisation
27 septembre 2012
Escherichia coli producteurde bêta-lactamase à spectre étendu : quelle est la part d'acquisition hospitalière ?
27 septembre 2012
Face à l'augmentation de l'incidence des infections nosocomiales à E. coli producteur de bêta-lactamase à spectre étendu (BLSE), notre objectif était d'identifier les cas possibles d'acquisition hospitalière des souches de E. coli BLSE durant une période de neuf mois dans notre centre hospitalier universitaire. L'étude reposait sur l'analyse de la distribution spatio-temporelle des cas, le typage moléculaire des souches et l'identification des gènes de résistance BLSE. Enfin une analyse cas/témoins devait permettre d'identifier les facteurs statistiquement associés aux cas. Sur un total de 64 cas d'infections à E. coli BLSE durant une période de neuf mois, le typage moléculaire a montré un total de 51 clones isolés chez un seul patient parmi les 61 souches typables. Seuls trois cas possibles pour un total de sept patients pouvaient relever d'une transmission croisée intra-hospitalière. Au total, la diversité clonale des souches des sept patients et la diversité des BLSE impliquées écartaient formellement cette hypothèse pour cinq de ces sept patients. Un seul cas de transmission croisée de gène de résistance était possible. L'étude cas/témoin a montré que seul un score de Charlson élevéétait significativement associéà l'acquisition d'une colonisation/infection à E. coli à BLSE. Au total, au vu de nos résultats, il apparaît peu faisable d'établir une stratégie de dépistage ciblé alors qu'une stratégie de dépistage à grande échelle aurait un rapport coût/bénéfice très discutable.
Évaluation de l'activité bactéricide des huiles essentielles sur des bactéries multirésistantes
27 septembre 2012
Objectif de l'étude. Mesurer l'efficacité de différentes huiles essentielles sur des souches cliniques. Matériel et méthodes. Six huiles essentielles ont été testées sur onze souches cliniques dont trois étaient multirésistantes aux antibiotiques. La méthode de l'aromatogramme a été utilisée pour évaluer l'activité bactériostatique des huiles essentielles. Les associations des huiles essentielles deux à deux ont été testées pour évaluer l'existence d'une éventuelle interaction sur chacune des souches testées. Résultats. Deux souches bactériennes ne répondaient à aucune des huiles essentielles testées : Enterobacter cloacae et Pseudomonas aeruginosa. Les huiles de girofle et de cannelle montraient une activité antibactérienne à très large spectre. Aucune différence de diamètre n'a été observée selon que la souche était de phénotype sauvage ou résistant, quelle que soit l'espèce testée. Les synergies observées concernaient pour l'essentiel trois espèces : Haemophilus influenzae, Streptococcus pneumoniae et Staphylococcus aureus. Conclusion. L'identification préalable des espèces est indispensable à l'utilisation puis au choix des huiles essentielles. Face à l'émergence et à la diffusion de la résistance bactérienne aux antibiotiques, l'exploration de méthodes fondées sur des produits et méthodes alternatives comme les huiles essentielles mérite d'être approfondie.
Évaluation de l'exposition à la contamination microbienne des avant-bras des soignants au cours des soins en service de gériatrie .
27 septembre 2012
L'exposition des avant-bras des professionnels de santé aux microorganismes au cours des soins a étéévaluée dans des services avec une activité gériatrique en établissements hébergeant des personnes âgées dépendantes ou en unités de soins de longue durée. Une exposition importante est retrouvée pour les aides-soignantes au cours de leurs activités. Staphylococcus aureus résistant à la méthicilline est retrouvé fréquemment sur les avant-bras des aides-soignantes, mais également sur ceux des infirmières et du kinésithérapeute. L'hygiène des avant-bras doit donc être prise en compte lors des soins comportant des contacts avec les avant-bras.
Évaluation d'une formation en ligne sur le bon usage des masques lors de la préparation à la pandémie grippale.
27 septembre 2012
La formation des professionnels est un aspect important dans les démarches de prévention des risques infectieux associés aux soins. Dans le cadre de la préparation à la pandémie, une action de formation en ligne a été développée au niveau du centre hospitalier de Rouffach concernant le bon usage des masques. Ce travail présente l'élaboration et le suivi de l'utilisation par enquête de satisfaction des agents d'une action de formation en ligne. Tous les agents de l'établissement avaient reçu la consigne de suivre la formation par leur responsable hiérarchique. Les résultats montrent une bonne adhésion de l'ensemble des professionnels de l'établissement avec un taux de validation du suivi par feuille d'émargement de 64,2 % (859/1 337). Dans les services de soins, la participation des catégories infirmières et aides-soignantes est respectivement de 79,2 % et 83,4 %. Le suivi des consultations sur internet (1 272 consultations) a permis de montrer que le suivi de la formation s'était étalé sur neuf semaines. L'analyse de la chronologie journalière met en évidence un suivi régulier sur toutes les tranches horaires entre 10 h 00 et 18 h 00. Les équipes de nuits ont également consulté ce lien entre 19 h 00 et 1 h 00 du matin. L'évaluation de la satisfaction des agents montre également une bonne adhésion des professionnels au projet mais l'organisation dans les services demandera àêtre mieux définie pour les futures formations : consultation en groupe, modalité de remontée des questions, accès au poste, temps définis pour ce suivi... En conclusion, les agents ont adhéréà l'action de formation en ligne et pour un établissement de santé, réussir le déploiement de cet outil est un enjeu stratégique dans la formation et l'actualisation des connaissances de ces professionnels.
Notices sur les pièces de l'abri de Fontalès (Tarn & Garonne), pour l'Exposition du Musée national de Préhistoire des Eyzies
26 septembre 2012
Assessing the impact of waste rocks on groundwater quality in the abandoned coal mine of Jerada city (north eastern Morocco)
26 septembre 2012
Endogenous regulation of the growth-rate responses of a spring-dwelling strain of the freshwater alga, Chlorella minutissima, to light and temperature
26 septembre 2012
Distribution of microplankton in relation to environmental variables during summer stratification in the Gulf of Hammamet, Tunisia
26 septembre 2012
Prévalence du portage d'entérobactéries productrices de beta-lactamase à spectre étendu chez les personnes âgées institutionnalisées et facteurs de risques associés.
25 septembre 2012
L'augmentation de l'incidence des entérobactéries productrices de β-lactamase à spectre étendu (EBLSE) représente un problème majeur de santé publique. La prévention de la transmission croisée nécessite la mise en place de précautions standard mais aussi de précautions complémentaires, s'appuyant notamment sur l'institution d'une stratégie de dépistage adaptée. Dans cet objectif, la connaissance de la prévalence du portage de EBSLE et des facteurs de risque associés s'avère indispensable, donnée toutefois non clairement établie pour les personnes âgées institutionnalisées. Dans notre étude, un écouvillonnage rectal a donc été réalisé pour tous les patients hospitalisés au sein de trois établissements disposant d'unités de soins de longue durée sur une période de deux mois. Parmi les 412 patients inclus, onze étaient porteurs de EBLSE (2,7 %, Intervalle de confiance à 95 % : 1,4-4,8), prévalence de portage faible en comparaison aux données de la littérature. Escherichia coli (54,5 %) était l'espèce majoritairement retrouvée. L'analyse statistique a montré que l'âge, le sexe, les antécédents urinaires et d'antibiothérapie au cours des six mois précédents étaient des facteurs de risque significatifs, le sexe féminin apparaissant comme protecteur. Au final, pour ces patients âgés institutionnalisés, une politique de dépistage ciblé sur les antécédents récents d'antibiothérapie et d'infections urinaires apparaît comme la plus pertinente.
Mobility of rare earth elements during igneous rocks weathering and associated stream water transport (Malaval catchment, Massif Central, France)
25 septembre 2012
Evaluation de l'impact financier pour l'hôpital d'une infection à Staphylococcus aureus en service de réanimation
25 septembre 2012
Différentes études ou rapports attribuent un surcoût hospitalier important aux infections nosocomiales. Ces surcoûts représentaient une perte financière " sèche " pour les établissements dont le financement reposait sur la dotation globale. L'objectif de cette étude était d'évaluer l'impact financier des infections nosocomiales pour un établissement financéà l'activité. Pour cette étude le choix a été fait d'évaluer l'impact financier des infections à Staphylococcus aureus sensible à la méticilline (SASM) en réanimation. Durant une année en réanimation adulte au centre hospitalier universitaire de Besançon, 116 patients ayant présenté un prélèvement positif à SAMS ont été inclus dans l'étude : 28 ont déclaré une infection durant leur séjour (les cas) et 88 sont restés des porteurs sains (les contrôles). Les données issues des laboratoires de bactériologie et d'hygiène hospitalière, mais aussi de la pharmacie hospitalière ont été utilisées de même que les données médicales disponibles dans le " Programme de médicalisation des systèmes d'information ". Concernant les cas et pour un séjour hospitalier, les résultats montraient une durée de séjour plus longue (p = 10-2). Pour les cas, le " montant financier restant " total à l'hôpital est significativement plus élevé pour chaque séjour (p = 0,03) alors que le " montant restant " journalier a tendance à baisser (p = 0,10). Ainsi, contrairement à la situation antérieure où l'infection nosocomiale représentait une perte financière sèche pour l'établissement, le financement à l'activité permet de valoriser financièrement l'infection nosocomiale.
Épidémiologie des infections à Pseudomonas aeruginosa
25 septembre 2012
Background Meticillin-resistant Staphylococcus aureus (MRSA) has spread throughout the world and has become highly endemic worldwide. The need for implementing MRSA control strategies is no longer a matter of debate. Aim To determine the temporal association between various infection control practices, the use of antibiotics and the incidence of MRSA in a 1200-bed French university hospital. Methods A multi-variate time-series analysis, based on monthly data from a nine-year period (January 2000-December 2008), was performed in a 1200-bed French university hospital to determine the temporal association between different variables and the incidence of MRSA. MRSA colonization pressure, infection control practices and use of antibiotics were considered in the analysis. Findings Time-series analysis showed a positive significant relationship between the incidence of hospital-acquired MRSA (HA-MRSA) and MRSA colonization pressure, the use of antibiotics (fluoroquinolones, macrolides and aminoglycosides) and the use of gloves. Conversely, a global negative correlation was observed between the incidence of HA-MRSA and the use of alcohol-based hand rub. Overall, the model explained 40.5% of the variance in the monthly incidence of MRSA. Conclusion This study showed that admission of patients with MRSA, the use of antibiotics and infection control practices contributed to the incidence of HA-MRSA. This suggests that efforts should be focused on high compliance with hand disinfection. These results also raise concerns about the use of gloves when caring for patients with MRSA.
Colloidal control on the distribution of major and trace elements in a small mountain stream (Malaval catchment, Massif Central, France)
24 septembre 2012
Mythes et symboles dans les manifestations artistiques du Paléolithique supérieur : la place des assemblages animal/animal et animal/humain
24 septembre 2012
Propositions pour une nouvelle lecture d'un galet gravé de l'abri de Fontalès (Tarn-et-Garonne)
24 septembre 2012
[Comparison of simple aspiration versus standard drainage in the treatment of large primary spontaneous pneumothorax].
21 septembre 2012
BACKGROUND: Chest tube drainage is the standard treatment of a large spontaneous pneumothorax. Aspiration is an alternative technique that is simple and rapid to learn, and the success rate seems identical to chest tube drainage. Its widespread use justifies studies to define its place in the management strategy of spontaneous pneumothorax. METHODS: We propose a multicentre, prospective, randomized, open trial with two parallel groups. The main objective is to compare the therapeutic efficacy of a simple aspiration with chest tube drainage for a first large spontaneous pneumothorax. The hypothesis is that aspiration is not inferior to a chest drain in its immediate effect. The secondary objectives are to compare the therapeutic efficacy at 24h and at one-week, the relapse rate at one year, and the tolerance and complications. A comparison of both the medical and economic aspects will be made. With an α-risk of 0.05 and a β-risk of 0.10, a proportion of failures of 30% expected in both groups and a target of non-inferiority of δ=0.15, the number of subjects to be included is 200 per group, totalling 400 in all. EXPECTED RESULTS: In the case of equivalence, this study should help to better define the place of aspiration compared to chest tube drainage in the management of spontaneous pneumothorax.
Physiological relevance and contribution to metal balance of specific and non-specific Metallothionein isoforms in the garden snail, Cantareus aspersus.
20 septembre 2012
Variable environmental availability of metal ions represents a constant challenge for most organisms, so that during evolution, they have optimised physiological and molecular mechanisms to cope with this particular requirement. Metallothioneins (MTs) are proteins that play a major role in metal homeostasis and as a reservoir. The MT gene/protein systems of terrestrial helicid snails are an invaluable model for the study of metal-binding features and MT isoform-specific functionality of these proteins. In the present study, we characterised three paralogous MT isogenes and their expressed products in the escargot (Cantareus aspersus). The metal-dependent transcriptional activation of the three isogenes was assessed using quantitative Real Time PCR. The metal-binding capacities of the three isoforms were studied by characterising the purified native complexes. All the data were analysed in relation to the trace element status of the animals after metal feeding. Two of the three C. aspersus MT (CaMT) isoforms appeared to be metal-specific, (CaCdMT and CaCuMT, for cadmium and copper respectively). A third isoform (CaCd/CuMT) was non-specific, since it was natively recovered as a mixed Cd/Cu complex. A specific role in Cd detoxification for CaCdMT was revealed, with a 80-90% contribution to the Cd balance in snails exposed to this metal. Conclusive data were also obtained for the CaCuMT isoform, which is involved in Cu homeostasis, sharing about 30-50% of the Cu balance of C. aspersus. No apparent metal-related physiological function was found for the third isoform (CaCd/CuMT), so its contribution to the metal balance of the escargot may be, if at all, of only marginal significance, but may enclose a major interest in evolutionary studies.
Differential liver proteome mapping of control and cadmium-fed rats.
20 septembre 2012
A comparative study of proteome maps from control and Cd-exposed rat liver was performed using a new technology of two-dimensional liquid chromatography separation method (PF-2D system, Beckman Coulter). Rats were fed for one month 0 or 100 μg Cd g(-1). The between-replicate and between-sample variations showed good repeatability and suitable reproducibility for the two dimensions of separation of proteins. In this complex mixture, PF-2D led to the separation of two major peaks which differed between control and Cd-exposed rat livers, one being identified by mass spectrometry as Cu/Zn superoxide dismutase (SOD), a well-known biomarker of Cd exposure, the other as phosphatidylethanolamine binding protein (PEBP). SOD content was decreased in Cd-exposed rat liver, compared to the control group which was corroborated by a significant decrease of SOD activity. PEBP content also tended to be decreased after Cd exposure. Present results demonstrate interest but also limitations of proteomic approach using PF-2D system to analyze effects of chemicals on organisms.
A decision tree to help determine the best timing and antiretroviral strategy in HIV-infected patients
20 septembre 2012
Serum C-reactive protein (CRP) and procalcitonin (PCT) levels and kinetics in patients with leptospirosis
20 septembre 2012
Clinical features and evolution of alveolar echinococcosis in France from 1982 to 2007: results of a survey in 387 patients.
30 août 2012
BACKGROUND & AIMS: Alveolar echinococcosis (AE) is a rare disease in humans, caused by the larval stage of the fox tapeworm Echinococcus multilocularis. METHODS: We present here 387 detailed AE cases diagnosed in France from 1982 to 2007 actively identified by a retrospective survey performed in 1997-1998 and prospectively thereafter. RESULTS: Male:female ratio was 1.03 and mean age 57.8 years at time of diagnosis. Among the 362 complete files (including 347 non dead-out and 15 dead-out lesions), 73% of the patients were symptomatic at first admittance. Among them, 83% presented with clinical patterns evocative either of a digestive or a hepatic disorder. Other symptomatic patients presented with erratic clinical pictures, generally due to metastasis or extra-hepatic location of the parasite. Except for a few patients with particularly severe AE who died shortly after the diagnosis, most patients were treated using benzimidazoles. Their mortality tends to merge with that of the general French population, matched by sex, age, and calendar year. This study also highlights an unexpectedly high frequency of blood-tied family cases (13% of patients submitted to a specific questionnaire). CONCLUSIONS: Even though the broad set of clinical features provoked by E. multilocularis makes AE a potential diagnostic trap for many physicians, our study revealed an improvement of its prognosis. However, as shown by our findings about the frequency of family cases, there is still a need for studies aimed at better describing this uncommon parasitic disease.
[Bevacizumab and lung cancer: eligible patients in daily practice].
19 juillet 2012
BACKGROUND: Combining bevacizumab with platinum-based chemotherapy significantly improves survival for patients with advanced non-squamous non-small cell lung cancer. The objective of this study was to assess the proportion of patients who could receive this combined therapy. METHODS: This was a retrospective single centre analysis of patients treated between 2007 and 2008. Exclusion criteria for bevacizumab included: squamous cell carcinoma, contraindication to platinum-based chemotherapy, uncontrolled hypertension, haemoptysis superior to 2.5 mL, recent surgery, and/or tomodensitometric criteria after independent review by two radiologists (contact with a proximal vessel, tracheobronchial involvement, cavitation). Cardiovascular diseases and central tumour location were not systematically considered as contraindications. RESULTS: Among 194 patients analysed, 21 (10.8%) to 35 (18%) patients were eligible for bevacizumab, whether or not cardiovascular diseases and central tumour location were considered as contraindications. The kappa coefficient was 0.49. CONCLUSION: Even though the proportion of patients who can receive chemotherapy plus bevacizumab may vary according to the eligibility criteria chosen and the interpretation of the CT scan, it is unlikely to exceed 25% of patients in daily practice.
Shellfish and residual chemical contaminants: hazards, monitoring, and health risk assessment along French coasts
3 juillet 2012
Spectrocolorimetric interpretation of sedimentary dynamics: The new "Q7/4 diagram"
15 juin 2012
Colour is a fundamental property of sediment and is often used for lithographic description to determine sedimentological structures, fades etc. However, the sedimentary information contained in this parameter is difficult to extract because it is difficult to quantify. Colour can be quantified by spectrocolorimetry which provides very high resolution data quickly and non-destructively. When adapted to sedimentology, spectrocolorimeters prove to be powerful tools due to their low purchase and maintenance costs, and some are portable and easily used in-the-field. Several methods have been used to extract sedimentological data from colorimetric spectra (first derivatives, factorial analysis, etc.). In the present study, we first provide a review of the sedimentological application of spectrophotometers and, after having described these methods, their advantages and disadvantages, we then describe a new tool called the Q7/4 diagram (abscissa L*; Ordinates 700/400 ratio). This new technique permits sedimentological units to be defined, allows the identification of different sediment components and provides 5 distinct poles: Clayey deposits, organic rich deposits (chlorophyll a and by products), altered organic matter deposits, iron rich deposits, carbonated deposits. Coupled with the analysis of first derivative spectra, it is possible to distinguish different pigments linked to the degradation and/or nature of the organic material (Chlorophyll a, melanoidin, etc.), the state of iron oxidation (for example, hematite and goethite-like signatures) and the nature of clays. The Q7/4 diagram permits rapid acquisition of high resolution data on changes of sediment dynamics in geosystems that have been subjected to highly varied climatic/environmental conditions. The instrument is non destructive, easy to use and maintain, portable for use in the field, fast to implement, is capable of high resolution, and has a vast range of possible applications. Spectrocolorimetry appears to provide many advantages and could become an essential and robust tool for preliminary sedimentological studies. (C) 2011 Elsevier B.V. All rights reserved.
Ontologies and Knowledge Aggregation in the Active Semantic Learning System
24 mai 2012
The construction of semantic-based learning systems depends on the development of ontologies and the capacity to integrate and exploit knowledge using semantic technologies, notably RDF and ontologies. In this paper we present some concepts and ontologies defined in the context of the Active Semantic Learning System (Active SLS) that are used to describe resources and the semantic relation between these concepts defined in different ontologies. The purpose is to obtain a learning system that is capable of aggregating knowledge from different sources from the web and to exploiting that knowledge for the benefit of the learner.
The placenta: a main role in congenital toxoplasmosis?
14 mai 2012
Systemic infections, such as toxoplasmosis, acquired during pregnancy can lead to placental infection and have profound effects on the mother-to-child relationship and the success of pregnancy. Placental permeability to Toxoplasma gondii is a main parameter that determines parasite transmission to the foetus, and the use of antibiotics to decrease placental parasite load and prevent congenital toxoplasmosis has been suggested for decades. Although parasitological examination of the placenta at birth is commonly used to diagnose neonatal congenital toxoplasmosis, this approach can be controversial. Here we argue in favour of placental examination for both diagnostic and epidemiological purposes.
Atmospheric phenanthrene pollution modulates carbon allocation in red clover (Trifolium pratense L.)
11 mai 2012
The influence of atmospheric phenanthrene (PHE) exposure (160 mgm 3) during one month on carbon allocation in clover was investigated by integrative (plant growth analysis) and instantaneous 13CO2 pulse-labelling approaches. PHE exposure diminished plant growth parameters (relative growth rate and net assimilation rate) and disturbed photosynthesis (carbon assimilation rate and chlorophyll content), leading to a 25% decrease in clover biomass. The root-shoot ratio was significantly enhanced (from 0.32 to 0.44). Photosynthates were identically allocated to leaves while less allocated to stems and roots. PHE exposure had a significant overall effect on the 13C partitioning among clover organs as more carbon was retained in leaves at the expense of roots and stems. The findings indicate that PHE decreases root exudation or transfer to symbionts and in leaves, retains carbon in a non-structural form diverting photosynthates away from growth and respiration (emergence of an additional C loss process).
Atmospheric phenanthrene transfer and effects on two grassland species and their root symbionts: A microcosm study
7 mai 2012
The objective of this work was to determine the transfer of phenanthrene (PHE) from air to grassland plants and soil compartments and its effects on the plant growth and symbiotic root microorganisms (arbuscular mycorrhizal fungi and Rhizobium nodules). The experimental procedure exposed Trifolium pratense L. or Lolium perenne L. to atmospheric PHE pollution (150 gm−3) over the course of one month. PHE was transferred from the air to the leaves and to the soil surfaces. In leaves, PHE was mostly absorbed in the inner leaf tissues, representing 92% and 73% of the total PHE amount quantified in leaves, respectively for clover and ryegrass. In soils, most of PHE contamination was recovered in the top layer (0-1 cm) and did not readily diffuse into the deep layer (1-10 cm). The highest PHE concentration recovered in deep roots (1.8 and 4.5 gg−1 dry weight (DW), respectively for clover and ryegrass) related to the lowest PHE concentration recovered in its associated soil suggested a PHE translocation from shoots to roots within the two plant species. The large PHE amount quantified in clover shoots (124 gg−1 DW) induced a significant diminution by 30% of the shoot biomass whereas root biomass remained stable. Efficient mycorrhizal symbiosis was maintained during exposure whereas the Rhizobium nodule symbiosis was altered in the surface of soil. By contrast, neither biomass accumulation nor symbiotic association was affected in ryegrass, probably due to a lower sensitivity of this species to PHE exposure. Perspectives of carbon allocation and nitrogen nutrition perturbations are suggested in clovers.
Monitoring groundwater in the discharge area of a complex karst aquifer to assess the role of the saturated and unsaturated zones
13 avril 2012
The hydrochemical response at springs in the drainage area of the Sierra del Rey--Los Tajos carbonate aquifer (province of Ma'laga, southern Spain) was monitored in order to determine the hydrogeological functioning of this aquifer. Analysis of the most important chemical parameters, using methodologies such as the temporal evolution of chemical components, principal component analysis and discriminant factorial analysis revealed that the high level of hydrochemical heterogeneity to be found in this discharge zone, in addition to particular spatial and temporal factors, is responsible for the mineralisation of the spring water. Sampling in karst systems where discharge occurs by several springs should take into account the hydrochemical variability of them; otherwise conclusions about the hydrological functioning of aquifers deduced from mixture of spring waters can be inaccurate.
How to protect groundwater catchments used for human consumption in karst areas?
13 avril 2012
The natural variability of catchment waters in karst areas requires treatment in order to respect the turbidity limit in the water supply. This water treatment reduces the range to be expected from protection areas. The creation of immediate, main and satellite protection areas is necessary. The longitudinal extension proposed for the inner protection area is based on a water transit time of 2 hours for the highest speeds in the aquifer under consideration. Delineating the inner protection area in such a way serves as a buffer in the event of accidental pollution. The selected intervention timeline allows for the interruption of pumping and keeps extraction and treatment equipment safe. The implementation of an outer protection area corresponding to a caution area may supplement the protection.
Annual and nycthemeral studies of the survival and circulation of indicator bacteria in a schist aquifer
13 avril 2012
Escherichia coli and Enterococci are widely used as indicators of faecal contamination of groundwater while total coliforms, which are of environmental but also of faecal origin, are indicators of the overall quality of the water. The survival of bacteria in groundwater is dependent on many factors including temperature, competition with indigenous bacteria and entrapment in aquifer material. Previous studies showed two sources of faecal contamination of a schist aquifer: infiltration into the ground from nearby septic tank effluents and seepage of landfill leachate. Water samples for bacterial analysis were collected from a piezometer on a monthly basis (15 months) and every six hours over two non-consecutive days. The intermittent sampling showed relatively stable concentrations of bacteria over time after the removal of stagnant water. Therefore, a continuous bacterial contamination without significant daily variation exists. The ratio of E. coli densities to total coliforms densities (EC/TC) allowed differentiation between the sources of faecal pollution in groundwater by comparing the populations of faecal bacteria with those of environmental bacteria. Enumeration indicated that the densities of bacteria were much higher in this schist aquifer than those in alluvial aquifers contaminated by a septic tank reported in the literature.
Isotopes and groundwater management strategies under semi-arid area: Case of theSouss upstream basin (Morocco)
13 avril 2012
This study concerns the Souss upstream basin. The objective is to investigate the characteristics of surface water and groundwater, to assess the impact of artificial recharge as reinforcement of the natural replenishment and assess the renewal of groundwater under semi-arid area. Two major water types are observed: (i) surface waters and upstream springs (least mineralized) and (ii) all groundwater samples (prevailing calcium and magnesium bicarbonate water type). Water isotopes show a low evaporation of precipitations during infiltration. Impoverishment in heavy isotopes is the characteristic of mountain rainfalls, or of a climate colder and wetter than present. Carbon-14 activities (34-94 pmc) indicate a long residence time. The artificial recharge is low compared to the reservoir volume, due to which the renewal rate is also low.
The bioaccumulation Performance of Reeds and Cattails in a Constructed Treatment Wetland for Removal of Heavy Metals in Landfill Leachate Treatment (Etueffont, France).
13 avril 2012
The aim of this study was to evaluate and compare the capacities of cattail (Typha latifolia L.) and reed (Phragmites australis L.) for heavy metal storage in the phytomass. Samples were studied in the fourth of the four interconnected natural lagooning basins of a constructed treatment wetland, developed as an integrated pilot system for the treatment of leachates in a domestic landfill site at Etueffont (Territoire de Belfort, France). The efficiency of the lagooning system was evaluated through physical and chemical parameter measurements over a period of three seasons. Anion/cation and heavy metal concentrations were sampled and analyzed in water flowing into and out of the lagooning basin. Simultaneously, reed and cattail biomass samples (roots/rhizomes, shoots) were collected at both inflow and outflow, and the biomass characteristics were determined. The average above-ground biomass of T. latifolia and P. australis varied, respectively, from 0.41 to 1.81 kg DW m−2 in the fall, 0.31 to 1.34 kg DW m−2 in winter, and 0.38 to 1.68 kg DW m−2 in spring, with significant seasonal variations. The greatest mean concentrations of heavy metals were found in the below-ground plant parts of the two species during the spring season. The average standing stock of heavy metals was higher in the below-ground than in the above-ground phytomass, whatever the season. With the exception of nickel, heavy metal concentrations in the inflow were correlated to the plant content of both species.
Characterization of groundwater in the Souss upstream basin : Hydrochemical and environmental isotopes approaches.
12 avril 2012
The hydrochemistry of major ions and environmental isotope compositions (18O, 2H) of water samples have been used to identify the chemical characteristics and the origin of groundwater in the Souss upstream basin. The total dissolved solids (TDS) did not exceed 1000 mg.L-1 with an average of 635 mg.L-1. Two chemical water types were observed: A calcium and magnesium bicarbonate type (Ca2+-Mg2+-HCO3-), forming the dominant water type generally observed in the plain along the Souss river and towards the piedmont of the Anti-Atlas Mountains; and a calcium sulphate type (Ca2+-SO42-), from the northwest of the study area, linked to the presence of phosphatic gypseous marls and limestone marls (Upper Cretaceous). The calculations of saturation indexes versus the main mineral phases have been carried out, using the PHREEQC program. The groundwater is saturated and slightly oversaturated with respect to carbonate minerals and under saturated with respect to evaporite minerals; surface waters show an oversaturation with respect to carbonate mineral phases, mainly dolomite. The groundwater composition is largely controlled by the dissolution of carbonate rocks known in this part of the basin. Stable isotope contents of groundwaters ranged from -7.96 to -6.26‰ for δ18O and from -49.47 to -39.28‰ for δD. The hydrogen (δD) and oxygen (δ18O) isotope signatures indicate a low evaporation of precipitations during infiltration and that the aquifer is highly influenced by the contribution of recharge water recharge from the High Atlas Mountains.
TOC and NO3-, two natural tracers of infiltration with different hydrochemical behaviour in karst aquifers
12 avril 2012
Analysis of TOC and NO3- contents in the water at four springs in the province of Malaga (southern Spain), sampled under different hydrologic conditions, revealed two different hydrochemical behaviour patterns for these natural tracers of infiltration. TOC content increased during every recharge period, following the rapid arrival of water infiltrating through the soil. On the other hand, NO3- content only rose during the first flood episodes (normally in autumn), and fell during the winter and spring ones. This difference is the consequence of the distinct biogeochemical kinetics of nitrogen with respect to organic carbon, both in the soil and within the aquifer. Unlike the mineralisation undergone by TOC from the surface to the spring, the NO3- ion remains in the aquifer almost unaffected, due to the oxidising conditions prevailing within the karst medium, which impede its denitrification and favour its preservation within the saturated zone. TOC and NO3- have a common origin in the soil and can be used to determine infiltration processes and the hydrogeological functioning of karst aquifers. Their different hydrogeochemical evolution provide information about mineralization and degradation processes of organic matter within karst aquifers, which can be used to validate the vulnerability to contamination in this type of medium.
Apport des isotopes de la molécule d'eau à la détermination de l'altitude de recharge des principales sources du Moyen Atlas calcaire (Maroc).
12 avril 2012
La présente étude est menée au Maroc sur le Moyen Atlas calcaire à caractère karstique. Son objectif est de contribuer à la caractérisation des aquifères moyens atlasique et à la détermination des altitudes de recharge des principales sources issues des calcaires dolomitiques liasiques afin d'aider à la détermination de leurs zones d'alimentation pour leur protection. La méthodologie utilisée est basée sur l'utilisation des isotopes stables de la molécule d'eau. La caractérisation chimique des eaux de ces sources montre que leur composition est le reflet de celle des roches-réservoirs qu'elles drainent d'une part et de l'évolution qu'elles subissent au cours de leur transit au sein de ces réservoirs d'autre part. L'analyse de l'évolution du deutérium en fonction de l'oxygène 18 permet de tracer une droite locale similaire à celle des pluies analysées au sein de la station de Fès, ce qui montre que les aquifères concernés se rechargent par une infiltration rapide, sans évaporation notable des eaux de pluie. Le gradient altimétrique pour l'oxygène 18 est établi à -0.27‰ par 100m. L'application de ce gradient aux teneurs isotopiques des autres sources analysées permet de remonter aux altitudes de recharge de ces sources. La confrontation de ces résultats aux données hydrogéologiques locales et régionales montre une concordance notable pour les sources dont les bassins versants étaient connus, et une orientation précieuse pour les sources dont les bassins étaient mal connus, avec des altitudes de recharge qui peuvent être 1090m plus élevées que les zones d'émergence. Ces résultats aident d'une manière certaine à déterminer les zones de recharge des sources, et donc à définir une stratégie de protection de cette ressource. The present study contributes to the characterisation of Middle Atlas limestone karst aquifers by implementing water stable isotopic techniques to determine the recharge altitudes of major springs issuing from Liassic dolomitic limestone, helping to delineate protection areas for the springs. Chemical analyses of spring waters show a composition that reflects both reservoir lithology and a chemical evolution over the course of flow within the reservoir. Analysis of the evolution of deuterium as a function of oxygen-18 suggests a local water line similar to that derived for rainwater at a station in Fez, indicating that the aquifers in question are recharged through rapid infiltration, without appreciable evaporation of the rainwater. Application of the established -0.27‰ per 100m altimetric gradient for oxygen 18 to the isotopic signatures of other analyzed sources allows us to backtrack recharge altitudes for these springs. Comparison of these results with local and regional hydrogeologic data shows a notable agreement among springs for which the drainage basin is known, and allows for more precise localization of springs for which the drainage basin is poorly known, with recharge altitudes reaching 1090m higher than emergence zones. To a certain extent, these results help to determine recharge zones for Middle Atlas springs and thus aid in strategizing protection for this resource.
Aspects quantitatifs et qualitatifs des eaux transitant par la grotte karstique de Hammamet Algérie
12 avril 2012
Les travaux portant sur la connaissance et le fonctionnement sont rares, en effet les derniers travaux effectués sur cette grotte sont très anciens. Cette situation freine les travaux actuels. Pour réaliser notre travail, nous nous sommes intéressés à la morphologie externe de la grotte. Le constat réalisé montre une morphologie gondolée traduisant la présence de petites dolines, ces dernières permettent l'infiltration des eaux dans les cavités. L'étude réalisée montre également la présence de sources sur la partie droite de la grotte en dessous de l'épikarst. Ce constat nous a permis de déduire une dissymétrie de la fissuration. En effet le coté gauche de la grotte est étanche, aucun écoulement ne se fait par contre le coté droit est très fissuré, ce qui favorise l'infiltration et la circulation des eaux. Les apports en eau sont soit directs, par infiltration des eaux de pluies soit indirects à partir des Djebels entourant la grotte, tel que le Djebel Tazbent, situéà plus haute altitude. Les débits jaugés à la sortie de la grotte varient en fonction des saisons et leur pluviosité. De ce fait à la sortie de la grotte les débits sont importants et peuvent atteindre 1 913L/s, par contre au niveau de l'oued Bouakous caractérisant la zone aval, le débit n'excède pas 10L/s. Les jaugeages différentiels effectués montrent une infiltration de 541L/s. Ces eaux vont modifier la composition chimique des eaux souterraines, ce dernier est bicarbonaté en période pluvieuse et devient chloruré en période sèche. Ce changement est accentué par la mise en solution des minéraux.
Infiltration processes in karst using an event-based conceptual model of flow and transport of dissolved organic carbon
12 avril 2012
The aim of this study is to characterize karst infiltration processes during flood events using a rainfall-discharge model coupled with a transport model for non-conservative solutes. The modelling approach is based on a classical karst devoted model with three connected reservoirs: SOIL (and epikarst) that feeds the aquifer partitioned into DIFFUSE and CONDUIT. Solute transport is modelled using mixing equations, including an empirical retardation factor in SOIL, as well as a first order solute decay. In order to take into account some specificities commonly observed in karst systems, three parameters are added to simulate overflows, piston-type flows in conduits, and a variation of the recharge area according to the initial hydrological conditions. To validate our approach, we used the dissolved organic carbon (DOC) as tracer, which is a non- conservative compound derived from the enrichment of infiltrated water into soil humic substances. The model was applied on a small karst system at Fertans in the French Jura mountains, where discharge and continuous measurements of DOC fluorescence are recorded. The model was calibrated and validated on a set of 19 flood events, showing that the model adequately simulated hydrographs and delayed chemographs during flood events with various rainfall intensities. A large variability of the recharge area was highlighted according to low and high groundwater level periods, and was attributed to the state of hydraulic connectivity in the unsaturated zone. The model simulate the contributions of pre-event and event waters during flood events and allow to better quantify the available resource considering the mixing effect of DOC. It shows, in particular, that total discharge of some flood events during dry periods are mainly composed by pre-event water via piston flow-type processes. Finally, this study show the ability of mixing model to properly simulate solute transport taking into account degradation and retardation processes.
La Bourgogne.
30 mars 2012
Pour l'archéologie funéraire en Gaule, la difficulté majeure réside dans l'inégalité quantitative et qualitative des données rendant difficile toute tentative de synthèse. Ce problème se pose notamment pour la question de la romanisation qui sera abordée ici du point de vue des pratiques funéraires du début du Haut-Empire (principalement du Ier siècle) en Bourgogne. Pour améliorer les données disponibles il est nécessaire de procéder tout d'abord à un bilan documentaire critique afin d'établir des priorités et des directions pour les recherches à venir.
Les moulins de l'abbaye de Cluny et le paléoenvironnement
28 mars 2012
Les chartes de l'abbaye de Cluny fournissent pour la région du Mâconnais de nombreuses mentions de moulins hydrauliques. Cette documentation permet de saisir le processus qui va amener l'abbaye à devenir un maître des capacités de la rivière Grosne entre le début du xe siècle et le xiie siècle. Au début de la période, dans les environs chronologiques de la fondation de l'abbaye, il apparaît que les rivières sont déjà bien équipées en moulins. Dès la première moitié du xe siècle, le lit de la Grosne situé en amont de l'abbaye possède un nombre équivalent de machines à celui que donne au xviiie siècle pour le même secteur la carte de Cassini. Dans leur construction et leur environnement, ces moulins connus par les textes pourraient se trouver très proches des moulins découverts près l'abbaye cistercienne d'Acey, sur la commune de Thervay dans le Jura. L'apport des techniques scientifiques actuelles s'avèrent nécessaire pour cerner, dans le cadre de la réflexion archéologique, ce phénomène, encore peu connu, qui caractérise les campagnes médiévales.
Analyses d'ouvrage N. Pousaz et al, 2009
27 mars 2012
Analyse de l'ouvrage de Nicole POUSAZ, Michel GUÉLAT, Laurence FREI PAROZ, Valérie PIUZ LOUBIER (avec des contributions de J. Affolter, C. Brombacher, M. Klee, D. Leesch, A.-M. Rachoud-Schneider, W. Schoch, N. Thew, G. Thierrin-Michael) : Delémont-En La Pran1 (volume 1). Environnement alluvial et premières installations humaines entre Mésolithique récent et âge du Bronze, publié dans Cahier d'archéologie jurassienne, 22, 2009, 256 pages, 192 figures, 31 planches et 1 dépliant. Ce volume publié vient s'ajouter aux nombreux ouvrages déjà consacrés aux résultats des fouilles effectuées sur le tracé de l'autoroute A16 Transjurane située sur le versant suisse du massif du Jura.
Chemical extractions and predicted free ion activities fail to estimate metal transfer from soil to field land snails.
26 mars 2012
This study investigates the relevance of several soil chemical extractions (calcium chloride, acetic acid, citric acid and a four-step sequential procedure) and predicted free metal ion activities in the soil solution to characterise the transfer of trace metals (Cd, Pb, and Zn) from soil to snail soft tissues over a large smelter-impacted area (Metaleurop Nord, Nord-Pas-de-Calais, France). The study was first performed on six snail species together and then specifically on Cepaea sp. and Oxychilus draparnaudi. When the six species were considered together, the accumulation of metals depended mostly on the species. When significant, total or extractable metal concentrations, or the predicted free ion activities, accounted for less than 7% of the variation of the metal concentrations in the snail tissues. Species-specific analyses showed that extractable concentrations explained approximately 25% of the variation of the metal concentrations in O. draparnaudi, and up to 8% in Cepaea snails. When using total soil concentrations and soil properties as explanatory variables, the models were generally slightly better, explaining up to 42% of the variance. The soil extraction procedures and predicted free ion activities used in this study did not accurately estimate the metal transfer from soil to snails and could not be used in risk assessment.
Experimental climate effect on seasonal variability of polyphenol/phenoloxidase interplay along a narrow fen-bog ecological gradient in Sphagnum fallax
26 mars 2012
Extracellular phenoloxidase enzymes play an important role in the stability of soil carbon storage by contributing to the cycling of complex recalcitrant phenolic compounds. Climate warming could affect peatland functioning through an alteration of polyphenol/phenoloxidase interplay, which could lead them to becoming weaker sinks of carbon. Here, we assessed the seasonal variability of total phenolics and phenoloxidases subjected to 2-3 °C increase in air temperature using open-top chambers. The measurements were performed along a narrow fen-bog ecological gradient over one growing season. Climate warming had a weak effect on phenoloxidases, but reduced phenolics in both fen and bog areas. Multivariate analyses revealed a split between the areas and also showed that climate warming exacerbated the seasonal variability of polyphenols, culminating in a destabilization of the carbon cycle. A negative relationship between polyphenols and phenoloxidases was recorded in controls and climate treatments suggesting an inhibitory effect of phenolics on phenoloxidases. Any significant decrease of phenolics through repeatedly elevated temperature would greatly impact the ecosystem functioning and carbon cycle through an alteration of the interaction of polyphenols with microbial communities and the production of extracellular enzymes. Our climate treatments did not have the same impact along the fen-bog gradient and suggested that not all the peatland habitats would respond similarly to climate forcing.
Effect of a temperature gradient on Sphagnum fallax and its associated living microbial communities: a study under controlled conditions.
26 mars 2012
Microbial communities living in Sphagnum are known to constitute early indicators of ecosystem disturbances, but little is known about their response (including their trophic relationships) to climate change. A microcosm experiment was designed to test the effects of a temperature gradient (15, 20, and 25°C) on microbial communities including different trophic groups (primary producers, decomposers, and unicellular predators) in Sphagnum segments (0-3 cm and 3-6 cm of the capitulum). Relationships between microbial communities and abiotic factors (pH, conductivity, temperature, and polyphenols) were also studied. The density and the biomass of testate amoebae in Sphagnum upper segments increased and their community structure changed in heated treatments. The biomass of testate amoebae was linked to the biomass of bacteria and to the total biomass of other groups added and, thus, suggests that indirect effects on the food web structure occurred. Redundancy analysis revealed that microbial assemblages differed strongly in Sphagnum upper segments along a temperature gradient in relation to abiotic factors. The sensitivity of these assemblages made them interesting indicators of climate change. Phenolic compounds represented an important explicative factor in microbial assemblages and outlined the potential direct and (or) indirect effects of phenolics on microbial communities.
Fine-scale horizontal and vertical micro-distribution patterns of testate amoebae along a narrow Fen/Bog gradient.
26 mars 2012
The ecology of peatland testate amoebae is well studied along broad gradient from very wet (pool) to dry (hummock) micro-sites where testate amoebae are often found to respond primarily to the depth to water table (DWT). Much less is known on their responses to finer-scale gradients, and nothing is known of their possible response to phenolic compounds, which play a key role in carbon storage in peatlands. We studied the vertical (0-3, 3-6, and 6-9 cm sampling depths) micro-distribution patterns of testate amoebae in the same microhabitat (Sphagnum fallax lawn) along a narrow ecological gradient between a poor fen with an almost flat and homogeneous Sphagnum carpet (fen) and a "young bog" (bog) with more marked micro-topography and mosaic of poor fen and bog vegetation. We analyzed the relationships between the testate amoeba data and three sets of variables (1) "chemical" (pH, Eh potential, and conductivity), (2) "physical" (water temperature, altitude, i.e., Sphagnum mat micro-topography, and DWT), and (3) phenolic compounds in/from Sphagnum (water-soluble and primarily bound phenolics) as well as the habitat (fen/bog) and the sampling depth. Testate amoeba Shannon H' diversity, equitability J of communities, and total density peaked in lower parts of Sphagnum, but the patterns differed between the fen and bog micro-sites. Redundancy analyses revealed that testate amoeba communities differed significantly in relation to Eh, conductivity, water temperature, altitude, water-soluble phenolics, habitat, and sampling depth, but not to DWT, pH, or primarily bound phenolics. The sensitivity of testate amoebae to weak environmental gradients makes them particularly good integrators of micro-environmental variations and has implications for their use in paleoecology and environmental monitoring. The correlation between testate amoeba communities and the concentration of water-soluble phenolic suggests direct (e.g., physiological) and/or indirect (e.g., through impact on prey organisms) effects on testate amoebae, which requires further research.
[Clusters of respiratory tract infections and alert strategy in nursing homes].
26 mars 2012
OBJECTIVE: Outbreaks of acute respiratory infections (ARI) are common in institutions for elderly people. We had for objective to investigate clusters of cases (lower respiratory tract infection and influenza-like illness [LRTI/ILI]) in order to improve and validate alert strategies in these institutions. METHODOLOGY: Prospective surveillance for LRTI/ILI was implemented in 11 institutions in Alsace, over five years. Clinical criteria were used to identify infected residents and clusters. Nasopharyngeal swabs were collected and rapid tests (Immunoassay) were performed to identify the influenza virus. RESULTS: The three week periods were analyzed if three cases or more were recorded during the first week. This analysis demonstrated an important risk of epidemic when this number of cases was reached in healthcare units. The influenza virus (10 clusters) and respiratory syncytial virus ([RSV], two clusters) were identified. CONCLUSION: The authors confirmed and emphasized the importance of adequate surveillance for clusters of respiratory tract infection cases. Early identification of an outbreak (three cases) is an important point to prevent transmission, especially during epidemic periods and if a virus is identified in the unit or institution.
Une lecture sous SIG des formes parcellaires rurales et urbaines de la plaine centrale de Venise
26 mars 2012
Salt spring in present rural world. An ethnoarchaeological approach in Moldavia (Romania)
26 mars 2012
The Subcarpathian area of Moldavia represents the ideal framework to perform extensive ethnoarchaeological research as there are here over 200 salt water springs near which are found archaeological deposits related to the exploitation of the salt water. Nowadays, these deposits are still exploited at an unexpected degree of intensity by the members of rural as well as of urban communities. The main research focuses on the identification of all salt springs in sub-Carpathian Moldavia and on the completion of complex ethnoarchaeological research (exploitation, use, distribution networks, commerce, hunting,halotherapy, social contexts, ethnoscience, symbolistics, etc.).
Spatial analysis of prehistoric salt exploitation in Eastern Carpathians (Romania)
26 mars 2012
This paper presents the first results of our project, an interdisciplinary Franco-Romanian collaboration focused on the dynamics of salt springs exploitation in the longue durée. In this analysis spatial and statistical measures, notably kernel densities, are used to investigate the relationship between salt spring exploitation and settlement dynamics from the Neolithic to Chalcolithic.
Centuriations romaines dans la plaine alluviale du Brenta (Vénétie)
26 mars 2012
In the second half of the 19th and (more specifically) in the first half of the 20th century, the materiality of centuriations in the plain of Venice was measured using vertical photography and medium-scale topographic mapping. The discourse surrounding this issue was thus shaped by a geohistorical perspective that incorporated the broader context of romanization and the agrarian question in Roman Antiquity. Recent findings in archaeogeography; geoarchaeology and preventive archaeology in France and Italy suggest that the nature of this key aspect of agrarian history needs to be re-examined. In examining the Brenta alluvial plain, the issue is not to seek fo an original form but to understand the social and environmental factors contributing to the construction of centuriated landscapes.
Hypersensitivity pneumonitis and metalworking fluids contaminated by mycobacteria (answer)
26 mars 2012
Diagnosis and treatment of digestive cryptosporidiosis in allogeneic haematopoietic stem cell transplant recipients: a prospective single centre study.
26 mars 2012
Digestive cryptosporidiosis (DC) can mimic GVHD after allogeneic haematopoietic stem cell transplantation (HSCT), thus requiring a reduction of immunosuppressive drugs and a specific therapy, whereas GVHD requires an intensification of immunosuppression. We systematically searched for cryptosporidiosis by light microscopy, immunochromatography and PCR in HSCT recipients who presented with at least one episode of diarrhoea. Of 115 consecutive patients allografted between July 2006 and November 2008, we analysed stools in 52 of 56 patients meeting these criteria. We identified Cryptosporidium parvum in 5 of the 52 patients (9.6%) at a median of 503 days (range 20-790) after HSCT. In those five patients, the median CD4+ cell and B lymphocyte counts were 60/mm3 (0-234) and 0/mm3 (0-96), respectively. Two patients died of invasive fungal infections. In the other three patients, diarrhoea disappeared after a median of 5 weeks following onset of bitherapy with azithromycine and nitazoxanide; they were still alive 433, 380 and 1179 days after the DC diagnosis. DC is probably under diagnosed after HSCT because it is difficult to detect during the asymptomatic phase. Early bitherapy and reduction of immunosuppression seem efficacious. In our series, DC has a seasonal pattern and is promoted by profound T lymphopenia.
Should possible recurrence of disease contraindicate liver transplantation in patients with end-stage alveolar echinococcosis? A 20-year follow-up study.
26 mars 2012
Liver transplantation (LT) is currently contraindicated in patients with residual or metastatic alveolar echinococcosis (AE) lesions. We evaluated the long-term course of such patients who underwent LT and were subsequently treated with benzimidazoles. Clinical, imaging, serological, and therapeutic data were collected from 5 patients with residual/recurrent AE lesions who survived for more than 15 years. Since 2004, [(18) F]-2-fluoro-2-deoxyglucose (FDG)-positron emission tomography (PET) images were available, and the levels of serum antibodies (Abs) against Echinococcus multilocularis-recombinant antigens were evaluated. Median survival time after LT was 21 years. These patients were from a prospective cohort of 23 patients with AE who underwent LT: 5 of 8 patients with residual/recurrent AE and 4 of 9 patients without residual/recurrent AE were alive in September 2009. High doses of immunosuppressive drugs, the late introduction of therapy with benzimidazoles, its withdrawal due to side effects, and nonadherence to this therapy adversely affected the prognosis. Anti-Em2(plus) and anti-rEm18 Ab levels and standard FDG-PET enabled the efficacy of therapy on the growth of EA lesions to be assessed. However, meaningful variations in Ab levels were observed below diagnostic cutoff values; and in monitoring AE lesions, images of FDG uptake taken 3 hours after its injection were more sensitive than images obtained 1 hour after its injection. In conclusion, benzimidazoles can control residual/recurrent AE lesions after LT. Using anti-rEm18 or anti-Em2(plus) Ab levels and the delayed acquisition of FDG-PET images can improve the functional assessment of disease activity. The potential recurrence of disease, especially in patients with residual or metastatic AE lesions, should not be regarded as a contraindication to LT when AE is considered to be lethal in the short term.
L'époque gallo-romaine des plaines de Saône aux plateaux jurassiens. Bilan des données palynologiques
26 mars 2012
Les analyses polliniques effectuées ces dernières années sur Centre-est (Franche-Comté-Bourgogne) permettent de retracer l'évolution de la végétation et des impacts anthropiques au cours de la période allant de l'âge du Fer au Haut Moyen Age. Au terme du Bronze final, parfois caractérisé par une forte emprise agricole, l'âge du Fer reste difficile à cerner dans les diagrammes polliniques, notamment parce qu'il est difficile d'obtenir des dates radiocarbone précises pour cette période. L'époque gallo-romaine est caractérisée par le retour d'un signal pollinique homogène montrant une emprise agricole plus ou moins importante en plaine comme en altitude. La déprise de la transition entre l'époque gallo-romaine et le Haut Moyen-Age illustre une fois de plus la non linéarité des processus d'anthropisation et de développement agropastoral. Il faut attendre le VIIe siècle, et surtout le VIIIe siècle, pour voir réapparaître un signal anthropique régulier, et arriver aux alentours de l'an Mil pour constater un net recul de l'espace forestier, notamment en altitude.
Landscape partitioning by nocturnal rodent assemblages in the Llanos de Ojuelos, in Mexico's Central High Plateau
26 mars 2012
Aim The Llanos de Ojuelos in Mexico's Central High Plateau supports unique Opuntia scrublands and the southernmost Chihuahuan grasslands. Although human activities have modified strongly its landscape and impacted its biodiversity at an unknown scale, such impacts are poorly known. We aimed at understanding how nocturnal rodent species distributed across the landscape and formed assemblages and on the role and integration of the different habitats at the landscape level. Location The study was carried out at 43 sites in a study area of approximately 3350 km2 in the Llanos de Ojuelos Methods During the Spring of 2008, we surveyed nocturnal rodents, through live-trapping. We redefined habitat classes based on log-linear multinomial regressions of rodent captures. Species rarefaction curves and true alpha, beta and gamma diversities were calculated for the different habitat classes. A map of the different habitats was constructed based on Landsat imagery. Results We captured 458 individuals of 20 rodent species. Multinomial regressions caused the merger of 11 a priori defined habitat classes into 7. Leguminous scrub and mixed nopaleras, both secondary habitats, had the highest alpha and gamma diversity values. Closed arboreal nopaleras and grasslands had the highest within-habitat variability (1Db) and the lowest area coverage. Within habitat 1Db was larger than landscape 1Db, because of the great overlap in rodent assemblage composition between the habitats. Main conclusions There are no 'typical' rodent assemblages per habitat class, but they are organized loosely and have fuzzy borders. Rodent community organization was highly species-centred. At the landscape level, secondary habitats have a profound effect on rodent diversity and should be included in management schemes for biological conservation. The most endangered habitats seem to be the closed arboreal nopaleras and grasslands. Any conservation efforts must consider their conservation and an increase in the size of remaining patches.
Changes in effective stress during the 2003-2004 Ubaye seismic swarm, France
16 mars 2012
We study changes in effective stress (normal stress minus pore pressure) that occurred in the French Alps during the 2003-2004 Ubaye earthquake swarm. Two complementary data sets are used. First, a set of 974 relocated events allows us to finely characterize the shape of the seismogenic area and the spatial migration of seismicity during the crisis. Relocations are performed by a double-difference algorithm. We compute differences in travel times at stations both from absolute picking times and from cross-correlation delays of multiplets. The resulting catalog reveals a swarm alignment along a single planar structure striking N130°E and dipping 80°W. This relocated activity displays migration properties consistent with a triggering by a diffusive fluid overpressure front. This observation argues in favor of a deep-seated fluid circulation responsible for a significant part of the seismic activity in Ubaye. Second, we analyze time series of earthquake detections at a single seismological station located just above the swarm. This time series forms a dense chronicle of +16,000 events. We use it to estimate the history of effective stress changes during this sequence. For this purpose we model the rate of events by a stochastic epidemic-type aftershock sequence model with a nonstationary background seismic rate λ0(t). This background rate is estimated in discrete time windows. Window lengths are determined optimally according to a new change-point method on the basis of the interevent times distribution. We propose that background events are triggered directly by a transient fluid circulation at depth. Then, using rate-and-state constitutive friction laws, we estimate changes in effective stress for the observed rate of background events. We assume that changes in effective stress occurred under constant shear stressing rate conditions. We finally obtain a maximum change in effective stress close to −8 MPa, which corresponds to a maximum fluid overpressure of about 8 MPa under constant normal stress conditions. This estimate is in good agreement with values obtained from numerical modeling of fluid flow at depth, or with direct measurements reported from fluid injection experiments.
Preservation of Permian allanite within an Alpine eclogite facies shear zone at Mt Mucrone, Italy: Mechanical and chemical behavior of allanite during mylonitization
16 mars 2012
This study addresses the mechanical and chemical behavior of allanite during shear zone formation under high-pressure metamorphism. Understanding physico-chemical processes related to the retention or resetting of Pb isotopes in allanite during geological processes is essential for robust petrochronology. Dating of allanite in meta-granodiorite showing variable amounts of strain (from an undeformed protolith to mylonite) at Monte Mucrone (Sesia Zone, NW Italy) gave surprising results. Based on structural and petrographic observations the shear zones at Mt Mucrone are Alpine, yet allanite located within an eclogite facies mylonite yielded Permian ages (208Pb/232Th average age: 287 ± 7 Ma). These mm-sized allanite grains are rimmed by an aggregate of coarse-grained garnet + phengite, thought to derive from former epidote. These aggregates were immersed in a weak matrix that experienced granular flow, and they were thus chemically and mechanically shielded during Alpine mylonitization. In undeformed samples (8a and 8b), two populations of epidote group minerals were found. Allanite forms either coronas around Permian monazite or individual grains with patchy zoning. Both types yield Permian ages (208Pb/232Th age: 291 ± 5 Ma). On the other hand, grains of REE-rich clinozoisite of Cretaceous age are found in undeformed rocks. These grains appear as small fragments with embayed surface outlines and minute satellites or rims around Permian allanite. These (re)crystallized grains are Sr-rich and show mosaic zoning. These results indicate that allanite crystals retained their chemical and isotopic characteristics, and thus their Permian age, as a result of strong strain partitioning between the epidote group porphyroclasts and the eclogite facies matrix in HP-mylonites. The observed partial mobilization of Pb isotopes, which lead to the Cretaceous-aged rims or grains in undeformed samples was facilitated by (re)crystallization of allanite and not by mere Pb diffusion alone under the HP conditions.
Comparison of simple aspiration versus standard drainage in the treatment of large primary spontaneous pneumothorax
14 mars 2012
Chest tube drainage is the standard treatment of a large spontaneous pneumothorax. Aspiration is an alternative technique that is simple and rapid to learn, and the success rate seems identical to chest tube drainage. Its widespread use justifies studies to define its place in the management strategy of spontaneous pneumothorax.
Apports des prospections non destructives à la connaissance du quartier artisanal antique de l'Essarté, Epomanduodurum, commune de Mathay, Doubs
7 mars 2012
L'Essarté est un quartier antique de potiers situé sur la commune de Mathay (Doubs). Il a été fouillé dans les années 1980-90. Dans le cadre d'un PCR consacré plus généralement à l'ensemble de l'agglomération antique de Mandeure-Mathay (Epomanduodurum) et aux espaces qui l'environnent, des prospections au sol ont été menées à l'Essarté en 2006, une synthèse des fouilles basée sur la documentation existante a été faite en 2009, et des prospections géophysiques ont été réalisées en 2009 et 2010. Par ailleurs, l'agglomération antique et ses alentours ont fait l'objet d'un relevé LiDAR en 2009. Cet article présente la mise en perspective des données acquises par les fouilles et par les prospections aériennes des années 1980-90 avec les informations obtenues à partir des résultats des prospections magnétiques, qui ont permis d'avoir des renseignements sur la nature du proche sous-sol, ainsi qu'à partir des prospections pédestres récentes et du relevé LiDAR (Light Detection And Ranging), qui informent sur ce qui est observable en surface, notamment sur les variations et micro-variations du relief grâce au LiDAR. Globalement, la nature du quartier antique et sa topographie ont pu être précisées, et des données nouvelles relatives à une occupation antérieure de la zone (nécropole) ont été acquises.
Friction velocity dependence of clay‐rich fault material along a megasplay fault in the Nankai subduction zone at intermediate to high velocities
22 février 2012
The frictional properties of clay‐rich fault material collected from a megasplay fault within the Nankai accretionary complex were examined in frictional experiments performed at a normal stress of 5 MPa under water‐saturated conditions for slip velocities from 0.0026 to 260 mm/s with >250 mm of displacement. Our results reveal that the fault material can show two stages of velocity weakening behavior: weakening at slow velocities (v < 2.6 mm/s), characterized by a small degree of friction velocity dependence (the absolute value of (a − b) is typically <0.005), and a dramatic weakening at high velocities (v > 26 mm/s). Such a process of fault weakening may provide important constraints on models of faulting along a megasplay fault. At slip velocities from 0.026 to 2.6 mm/s, there exist both velocity‐weakening and velocity strengthening fault materials. The frictional coefficient values, m, for slow slip velocities (v = 0.26 mm/s) are relatively low (m = 0.28-0.35) for velocity‐strengthening samples compared with velocity‐weakening samples (m = 0.38-0.49). Microstructural analyses reveal that velocity‐strengthening samples show homogeneous deformation textures in which the entire gouge layer is deformed, whereas velocity‐weakening materials show evidence of shear localization in which deformation is concentrated along narrow subsidiary shears
Progressive illitization in fault gouge caused by seismic slip propagation along a megasplay fault in the Nankai Trough
22 février 2012
The question of whether coseismic ruptures along megasplay faults in accretionary prisms (i.e., large landward-dipping thrust faults branching from the plate boundary) reach the seafl oor is critical for assessing the risk of tsunami disaster. However, samples from active megasplay faults have not previously been available. Here we present geochemical and mineralogical data of megasplay fault samples obtained from the shallow (<300 m below seafl oor) portion of the megasplay fault that coincides with the rupture area of the A.D. 1944 Tonankai earthquake in the Nankai Trough. The megasplay fault zone is characterized by localized shear zones of brecciated host rocks. A prominent slip zone, here termed "dark gouge," was discovered within one of the shear zones. Compared to the surrounding breccias, the dark gouge is chemically enriched in Al and K, and depleted in Ca and Sr. It is also characterized by higher illite content in illite-smectite mixed-layer clays. These chemical and mineralogical features may refl ect a transformation in clay mineralogy caused by frictional heating, and suggest that the seismic slip can propagate to very shallow levels along megasplay fault systems
Development of a sensitive method for Toxoplasma gondii oocyst extraction in soil.
20 février 2012
Toxoplasmosis is a world-wide infection caused by Toxoplasma gondii. Oocysts disseminated in the environment by infected cats provide a major source of infection for humans and intermediate hosts. The level of soil contamination and the dynamics of this contamination are mostly unknown due to the lack of sensitivity of detection method. Our aim was to improve the detection of T. gondii oocysts in soil samples by comparing three extraction protocols (A, B and C) on unsporulated and sporulated oocysts of different strains and ages, and by testing the effect of sporulation and soil characteristics on oocyst recovery using the most efficient method. The oocyst recovery obtained using protocol C, in which the flotation solution was placed under the sample solution after the dispersion step, was at least ten-fold higher than protocols A and B, in which the sample was just filtered before flotation. The efficiency of protocol C, tested on five artificial soil matrices and four natural soils inoculated with oocysts, was lowest in soils with high proportions of sand. We recommend the protocol C for field investigations, and we advise that results should be interpreted with caution, considering the effect of soil characteristics, especially sand content, on oocyst recovery.
Changes in human alveolar echinoccocosis distribution and fox infection in Franche-Comte, France: a 30 year survey
19 février 2012
In France, human AE cases are systematically recorded since the end of the 70s and are managed at the Besançon University Hospital in the FranceEchino National register since 2003. This allowed a retrospective analysis of a subset of 245 patients diagnosed in the region of Franche-Comté and the surrounding departments (French administrative divisions) over the last 30 years in order to detect spatial and temporal trends of alveolar echinococcosis (AE). From 1980 to 2010, no changes in the average incidence could be detected on the regional scale. However, the number of human cases significantly decreased in the Doubs department and coincidently increased in the neighbouring Haute-Saône. Kulldorff's statistics indicate a multi-scale aggregation of human cases in space and time. First the Franche-Comté region appeared to form a significant cluster of higher prevalence compared to the surrounding departments. Within the region, a large and significant cluster of AE prevalence was detected in the Doubs department (mostly on the Jura plateau) in the period 1980-89. It split into two clusters of smaller size in 1990-99. Then clusters faded in 2000-2010 and areas of higher prevalence maintained on the Doubs plateaus and extended to the eastern part of the Haute-Saône and the Jura departments. Moreover, the occupational profile of patients changed over the 30 years of the present study with a large decrease of the 'farmer' category. Fox infection surveys were carried out in 1980-89, 1996-2001 and 2007-2010. They show a clear extension of higher prevalence areas towards the north-west of the traditional highly endemic areas of the Jura mountains. This spatial extension may explain the transition from a clustered distribution to a greater homogeneity of human AE prevalence over the region during the study period. Those results solidly support the idea that important changes in human AE distribution and fox infection have occurred in Franche-Comté since the 80s and may still be ongoing.
Landscape, biodiversity and human alveolar echinococcosis distribution: can ecological theory predict disease hotspots in China?
19 février 2012
To understand infectious disease emergence is one of the current frontiers in environment and health sciences. E. multilocularis sustainability and thus human exposure, in world ecosystems depends on both the existence of suitable host communities supporting the parasite population and meteorological conditions compatible with the survival of free-living eggs. Thus, transmission is an inherently ecological process involving interactions among many species Predictions based on the ecological theory can be made in such complex systems. One is related to the "dilution effect": the diversity of wild animal species may dilute pathogen transmission and thus human exposure to pathogens. In this case transmission intensity would be lower in biodiversity hotspots. Another prediction is that climatic conditions may impact the free-living stages of the parasite (e.g. cold climates and humidity are more favourable to egg survival). A third prediction is that anthropogenic landscapes can impact the population dynamics of species within communities and thus transmission intensity (making e.g. intermediate host population outbreaks and intensive prey-predator interaction more likely). Here we present the results obtained on the scales of continental China and of the eastern border of the Tibetan plateau. Based on data available on human AE distribution, it combines quantified analysis of small mammal biodiversity, land cover and climates. On continental scale, we found that rainfall, altitude and temperature alone do not correlate well to human AE distribution. Small mammal biodiversity, even considering the distribution and the number of small mammal species that are known to be potential pests and intermediate hosts do not correlate to the spatial distribution of human AE. Furthermore, the spatial correlation between the spatial distribution of two of the global land cover 2000 categories, 'meadows' and 'alpine and subalpine meadow', and the spatial distribution of AE is very clear, confirming results obtained in earlier works. On the Tibetan plateau, the analysis was based on a mass screening of 15614 people and 81 villages in a 290,400 km2 area of southern Qinghai and western Sichuan. The Qinghai-Sichuan AE focus lie in one of the area with the lowest regional biodiversity of small mammal in China except if only pest and intermediate host species are considered. A regional model was computed using Bayesian methods. We found there that human AE prevalence was more correlated to landscape and climate variables. An extrapolation of this model on a larger area of 902,800 km2 including Eastern Tibetan Autonomous Region (TAR) and South-Western Gansu predicted correctly the well-know focus of Puma-Zhang county in Gansu, the absence of AE (or the lower of prevalence) observed around the Qinghai lake. It also predicted two possible hotspots in the TAR.
Clay minerals as good proxys for thrust fault P-T conditions estimation : Example of Monte Perdido thrust fault (southern Pyrenees).
16 février 2012
Grandes haches en roches alpines (et quelques autres) trouvées dans le Benelux : synthèse des analyses spectroradiométriques
15 février 2012
Abbozzi di anelloni neolitici nel massicio del Monviso a Oncino e Crissolo (Cuneo, Piemonte)
15 février 2012
The alpine Beilnacken aus Kamegg (Niederösterreich) und die Verbreitung des Bégude-Typs in Westeuropa
15 février 2012
Old friends, new friends, a long-lost friend and false friends: tales from Projet JADE
15 février 2012
Eclogite or jadeitite : the two colours involved in the tranfer of alpine axeheads in western Europe
15 février 2012
De l'image à l'objet : détermination de la provenance d'artefacts archéologiques par spectroradiométrie en réflectance diffuse
15 février 2012
Measuring distinction in the megalithic architecture of the Carnac region : from site to material
15 février 2012
Outils d'évaluation de la biodisponibilité des contaminants dans les sols et apport en évaluation des risques pour les écosystèmes.
15 février 2012
La biodisponibilité est la part des contaminants du milieu disponible pour l'assimilation par les organismes. Elle peut être déterminée par mesure des effets (= biodisponibilité toxicologique) et/ou de la bioaccumulation (= biodisponibilité environnementale) des contaminants chez des organismes exposés en laboratoire ou in situ à des sols contaminés. Des exemples d'utilisation des escargots et des plantes pour évaluer la biodisponibilité sont présentés. http://www2.ademe.fr/servlet/KBaseShow?sort=-1&cid=96&m=3&catid=10143
Spatially explicit analysis of metal transfer to biota: influence of soil contamination and landscape.
15 février 2012
Concepts and developments for a new field in ecotoxicology, referred to as "landscape ecotoxicology," were proposed in the 1990s; however, to date, few studies have been developed in this emergent field. In fact, there is a strong interest in developing this area, both for renewing the concepts and tools used in ecotoxicology as well as for responding to practical issues, such as risk assessment. The aim of this study was to investigate the spatial heterogeneity of metal bioaccumulation in animals in order to identify the role of spatially explicit factors, such as landscape as well as total and extractable metal concentrations in soils. Over a smelter-impacted area, we studied the accumulation of trace metals (TMs: Cd, Pb and Zn) in invertebrates (the grove snail Cepaea sp and the glass snail Oxychilus draparnaudi) and vertebrates (the bank vole Myodes glareolus and the greater white-toothed shrew Crocidura russula). Total and CaCl(2)-extractable concentrations of TMs were measured in soils from woody patches where the animals were captured. TM concentrations in animals exhibited a high spatial heterogeneity. They increased with soil pollution and were better explained by total rather than CaCl(2)-extractable TM concentrations, except in Cepaea sp. TM levels in animals and their variations along the pollution gradient were modulated by the landscape, and this influence was species and metal specific. Median soil metal concentrations (predicted by universal kriging) were calculated in buffers of increasing size and were related to bioaccumulation. The spatial scale at which TM concentrations in animals and soils showed the strongest correlations varied between metals, species and landscapes. The potential underlying mechanisms of landscape influence (community functioning, behaviour, etc.) are discussed. Present results highlight the need for the further development of landscape ecotoxicology and multi-scale approaches, which would enhance our understanding of pollutant transfer and effects in ecosystems.
Structure et évolution de l'occupation rurale en Bourgogne du Nord de la fin de l'époque laténienne au début de l'époque romaine
14 février 2012
Neoproterozoic extension in the Greater Dharwar Craton: a reevaluation of the "Betsimisaraka suture" in Madagascar
13 février 2012
The Precambrian shield of Madagascar is reevaluated with recently compiled geological data and new U-Pb sensitive high-resolution ion microprobe (SHRIMP) geochronology. Two Archean domains are recognized: the eastern Antongil-Masora domain and the central Antananarivo domain, the latter with distinctive belts of metamafic gneiss and schist (Tsaratanana Complex). In the eastern domain, the period of early crust formation is extended to the Paleo-Mesoarchean (3.32-3.15 Ga) and a supracrustal sequence (Fenerivo Group), deposited at 3.18 Ga and metamorphosed at 2.55 Ga, is identified. In the central domain, a Neoarchean period of high-grade metamorphism and anatexis that affected both felsic (Betsiboka Suite) and mafic gneisses (Tsaratanana Complex) is documented. We propose, therefore, that the Antananarivo domain was amalgamated within the Greater Dharwar Craton (India + Madagascar) by a Neoarchean accretion event (2.55-2.48 Ga), involving emplacement of juvenile igneous rocks, high-grade metamorphism, and the juxtaposition of disparate belts of mafic gneiss and schist (metagreenstones). The concept of the ''Betsimisaraka suture'' is dispelled and the zone is redefined as a domain of Neoproterozoic metasedimentary (Manampotsy Group) and metaigneous rocks (Itsindro-Imorona Suite) formed during a period of continental extension and intrusive igneous activity between 840 and 760 Ma. Younger orogenic convergence (560-520 Ma) resulted in east-directed overthrusting throughout south Madagascar and steepening with local inversion of the domain in central Madagascar. Along part of its length, the Manampotsy Group covers the boundary between the eastern and central Archean domains and is overprinted by the Angavo-Ifanadiana high-strain zone that served as a zone of crustal weakness throughout Cretaceous to Recent times.
Circum-Mediterranean fire activity and climate changes during the mid Holocene environmental transition (8500-2500 cal yr BP)
13 février 2012
Contrasting patterns of precipitation seasonality during the Holocene in the south- and north-central Mediterranean
13 février 2012
Evolution of habitat and environment of red deer (Cervus elaphus) during the Lateglacial and early Holocene in eastern France using stable isotope composition ( d13C, d15N, d18O) of archaeological bones.
13 février 2012
This paper studies the evolution and habitat of red deer (Cervus elaphus) during the Lateglacial and early Holocene in eastern France using stable isotope composition ( d13C, d15N, d18O) of archaeological bones.
La contribution des archives naturelles à l'histoire des activités minières et métallurgiques en Bourgogne (Morvan, Nivernais - France)
13 février 2012
Isotopic evidence for dietary ecology of cave lion (Panthera spelaea) in North-Western Europe: prey choice, competition and implications for extinction
13 février 2012
This paper studies dietary ecology of cave lion (Panthera spelaea) through isotopic evidence
Are pathogenic bacteria just looking for food? Metabolism and microbial pathogenesis.
9 février 2012
It is interesting to speculate that the evolutionary drive for microbes to develop pathogenic characteristics was to access the nutrient resources that animals provided. Animal environments that pathogens colonize have likely driven the evolution of new bacterial characteristics to maximize these new nutritional opportunities. This review focuses on genomic and functional aspects of pathogen metabolism that allow efficient utilization of nutrient resources provided by animals. Similar to genes encoding specific virulence traits, genes encoding metabolic functions have been horizontally acquired by pathogens to provide a selective advantage in host tissues. Selective advantage in host tissues can also be gained by loss of function mutations that alter metabolic capabilities. Greater understanding of bacterial metabolism within host tissues should be important for increased understanding of host-pathogen interactions and the development of future therapeutic strategies.
Mupirocin resistance is not an inevitable consequence of mupirocin use.
9 février 2012
The rate of mupirocin resistance in meticillin-resistant Staphylococcus aureus (MRSA) in Besançon University Hospital is low with a decreasing trend, from 10% in 2004 to 3% in 2009. This trend in resistance paralleled mupirocin consumption. Genotyping results showed that this decrease was not linked to a change in MRSA clones. It appears that the way in which the mupirocin is used, rather than the volume, plays a role in the emergence of resistance and that its cautious use is likely to maintain the mupirocin resistance at a low level, thus preserving its efficacy.
Methicillin-susceptible ST398 Staphylococcus aureus responsible for bloodstream infections: an emerging human-adapted subclone?
9 février 2012
In the course of an annual 3-month bloodstream infections (BSI) survey conducted during a four-year period in 31 healthcare institutions located in three noncontiguous French regions, we report 18 ST398 Staphylococcus aureus BSI. ST398 BSI incidence showed a seven-fold increase during the study period (0.002 per 1,000 patient days in 2007 vs. 0.014 in 2010). ST398 BSI isolates differed from the pig-borne multiresistant clone: 17/18 BSI isolates were methicillin susceptible and none was of t011, t034 or t108 pig-borne spa-types. ST398 BSI isolates had homogenous resistance patterns (15/18 with only Ery(r)) and prophagic content (all harboured the hlb-converting Sau3int phage). The clustering of BSI and pig-borne isolates by spa-typing and MLVA, the occurrence of Sau3int phage in BSI isolates and the lack of this phage in pig-borne isolates suggest that the emergence of BSI isolates could have arisen from horizontal transfer, at least of the Sau3int phage, in genetically diverse MSSA ST398 isolates. The acquisition of the phage likely plays a role in the increasing ability of the lysogenic ST398 isolates to colonize human. The mode of acquisition of the non pig-borne ST398 isolates by our 18 patients remains unclear. ST398 BSI were diagnosed in patients lacking livestock exposure and were significantly associated with digestive portals of entry (3/18 [16.7%] for ST398 vs. 19/767 [2.5%] for non ST398 BSI; p = .012). This raises the question of possible foodborne human infections. We suggest the need for active surveillance to study and control the spread of this human-adapted subclone increasingly isolated in the hospital setting.
Sorption onto crosslinked cyclodextrin polymers for industrial pollutants removal: An interesting environmental approach
6 février 2012
Traitements conventionnels et émergents des eaux usées de la filière traitement de surface
6 février 2012
Entre forme d'habitat groupé et forme d'habitat dispersé : le cas intermédiaire d'une occupation rurale aux IIIe et IVe siècles ap. J.-C. entre Fragnes et Virey-le-Grand au nord-est de Chalon-sur-Saône (Saône-et-Loire)
2 février 2012
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 iii e siècle au milieu du iv e 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
Le Néolithique du Morvan : état des connaissances
2 février 2012
La région du Morvan, en particulier le massif granitique, constitue une très grande aire géographique au sein de laquelle la Préhistoire reste encore très mal connue. L'état des connaissances est assez différent entre le massif du Morvan et les vallées adjacentes du Serein, de l'Arroux, de l'Aleine et de l'Yonne. L'industrie lithique de quelques sites du haut Morvan a permis de mettre en évidence une première fréquentation mésolithique et plusieurs sites de hauteur occupés à partir du Néolithique moyen et au Néolithique final, dont une probable enceinte du Néolithique moyen sur le Mont Beuvray. Des études complémentaires dans la vallée de l'Arroux permettent de confirmer l'important développement de l'habitat et l'érection de menhirs au Néolithique moyen. Les découvertes concernant le Néolithique final semblent moins nombreuses et plus ponctuelles. Les trop rares indices culturels permettent d'évoquer la présence du Chasséen, du Néolithique Moyen Bourguignon, de plusieurs groupes du Néolithique final et du Campaniforme, aussi bien dans le haut Morvan que dans les vallées périphériques du massif
Geochemistry and age of the Nouméa Basin lavas, New Caledonia: Evidence for Cretaceous subduction beneath the eastern Gondwana margin
27 janvier 2012
The Nouméa Basin in New Caledonia is perhaps the best preserved sequence of in-situ Late Cretaceous marine sediments and volcanic rocks in the western Pacific region. Previous tectonic interpretations suggest that the basin formed during a period of large-scale extension between New Caledonia and Antarctica during the break-up of the eastern Gondwana margin. However, new geochemical analyses have identified continental arc signatures in the lavas, suggesting a well-developed Late Cretaceous volcanic arc system active in the New Caledonia sector of the eastern Gondwana margin, possibly extending as far south as New Zealand. There are two distinct suites of lavas in the Nouméa Basin. The older lavas are predominately mafic, low to high-K, and have a calc-alkaline fractionation trend. Chondrite normalised trace element plots show patterns that are light rare earth element (LREE) enriched, and mid-ocean ridge basalt (MORB) normalised trace element plots show enrichment of most incompatible trace elements with discernable negative Nb, Ta and Ti anomalies. Trace element ratios identify a continental arc signature in these lavas which were generated from an N-MORB-like source. Overlying the mafic lavas is a sequence of younger voluminous siliceous, generally subalkaline lavas (+/−88 Ma). These lavas are LREE enriched with slight positive Nb-Ta anomalies and negative Eu and Ti anomalies. The geochemical data indicates these lavas have within plate characteristics with minor continental affinities and an enriched source. We propose that the older mafic lavas were generated during large scale subduction under the eastern Gondwana margin during the Late Cretaceous. Whereas the younger lavas may have been generated during extension; caused by slab roll-back of the subduction system along the Southwest Pacific plate boundary. The presence of fragments of a detached slab in this process would result in lavas chemically similar to those found in the Nouméa Basin, with minor continental characteristics, and generated from an enriched mantle source. What is of fundamental importance is the evidence that the arc system extended from New Caledonia southwards to New Zealand and was likely contemporaneous
Oxidation of zinc-thiolate complexes of biological interest by hydrogen peroxide: a theoretical study
26 janvier 2012
Zinc-thiolate complexes play a major structural and functional role in the living cell. Their stability is directly related to the thiolate reactivity towards reactive oxygen species (ROS) naturally present in the cell. Oxidation of some zinc-thiolate complexes has a functional role, as is the case of zinc finger redox switches. Herein, we report a theoretical investigation on the oxidation of thiolate by hydrogen peroxide in zinc finger cores of CCCC, CCHC and CCHH kinds containing either cysteine or histidine residues. In the case of CCCC core, the calculated energy barrier for the oxidation to sulfenate of the complexed thiolate was found to be 16.0 kcal mol-1 that is 2 kcal mol-1 higher than that for the free thiolate. The energy barrier increases to 19.3 kcal mol-1 and to 22.2 kcal mol-1 for the monoprotonated and, respectively, diprotonated CCCC cores. Substitution of cysteine by histidine also induces an increase in the magnitude of the reaction energy barrier: it becomes 20.0 and 20.9 kcal mol-1 for the CCCH and CCHH cores, respectively. It is concluded that the energy barrier for the oxidation of zinc fingers is strictly dependent on the type of ligands coordinated to zinc and on the protonation state of the complex. These changes in the thiolate reactivity can be explained by the lowering of the nucleophilicity of complexed sulfur and by the internal reorganization of the complex (changes in the metal-ligand distances) upon oxidation. The next reaction steps subsequent to sulfenate formation are also considered. The oxidized thiolate (sulfenate) is predicted to dissociate very fast: for all complexes, the calculated dissociation energy barrier is lower than 3 kcal mol-1. It is also shown that the dissociated sulfenic acid can interact with a free thiolate to form a SS bridge in a reaction that is predicted to be quasi diffusion-limited. The interesting biological consequences of the modulation of thiolate reactivity by the chemical composition of the zinc finger cores are discussed.
Effets des pesticides de la vigne sur le cycle biologique de l'escargot dans divers contextes d'exposition
25 janvier 2012
De plus en plus de substances chimiques sont produites dans le monde et une grande partie d'entre elles entrent dans la composition des produits phytosanitaires. La France en est le premier consommateur européen et le troisième au niveau mondial. L'objectif de nos recherches est de comprendre le devenir et les effets de ces molécules dans l'environnement, notamment agricole, grâce à l'utilisation d'un invertébré bioindicateur, l'escargot Helix aspersa. Nous avons choisi de caractériser l'exposition, le transfert et les effets sur l'escargot de 8 formulations commerciales de fongicides et d'herbicides (Roundup® et Bypass® = glyphosate; Basta® = glufosinate; Valiant® Flash = folpel + cymoxanil + fosétyl-Al; Corail® = tébuconazole; Cabrio® Top = pyraclostrobine + métirame-Zn; Thiovit® = soufre; Bouillie bordelaise = cuivre), communément utilisées en viticulture. Une étude réalisée en conditions in situ a permis de quantifier les retombées au sol des pesticides appliqués sur la vigne, dans la parcelle et en périphérie mettant en évidence les dépôts suite à la dérive des substances. En parallèle, peu d'effets ont été démontrés sur la survie et la croissance d'escargots juvéniles placés en microcosmes et soumis aux différents traitements de pesticides, mis à part un effet inhibiteur du Roundup® sur la masse des organismes, probablement en relation avec d'importants dépôts au sol, l'accumulation et la métabolisation de la substance active dans les tissus. Une méthode d'extraction et d'analyse de deux herbicides (glyphosate et glufosinate) dans le sol a été développée afin de pouvoir mesurer les concentrations d'exposition pour diverses expériences et de caractériser leur persistance dans ce sol de vigne. Les effets du Bypass® et du Basta® ont étéétudiés sur l'ensemble du cycle de vie de l'escargot en conditions contrôlées. Aucun effet significatif sur la survie et la croissance n'a été démontré bien qu'une accumulation de glyphosate ait été quantifiée chez des escargots (6 mg kg-1) nourris continuellement par de l'aliment contaminé (à 30 mg kg-1). Cependant, une exposition au glyphosate des escargots durant le développement embryonnaire semble perturber leur reproduction (diminution de la fertilité) du fait d'un effet différé de cet herbicide. Les cibles potentiellement affectées au niveau du contrôle neuroendocrine sont discutées. Tous les pesticides inhibent l'éclosion des œufs de l'escargot à des concentrations inférieures à celles appliquées au champ et l'influence des caractéristiques du sol sur leur toxicité a été démontrée. Ces effets ont été mis en évidence lors d'expériences réalisées en laboratoire dans le cadre d'un développement de bioessais d'embryotoxicité. Ces travaux de thèse ont apporté des connaissances sur le comportement, en surface et dans le sol, ainsi que dans l'escargot (transfert, toxicité), de plusieurs pesticides appliqués sur la vigne. Ils ont également permis de développer plusieurs outils (bioessais de laboratoire, dispositif d'exposition sur le terrain) visant à améliorer les procédures d'évaluation du risque des pesticides dans l'environnement terrestre. Les techniques d'analyse de ces composés mises au point pour des matrices complexes (sols, tissus animaux), constituent un apport original pour l'évaluation du risque environnemental et sanitaire. D'importantes difficultés analytiques ont été rencontrées et il n'a pas été possible de finaliser les méthodes de dosage pour la totalité des substances. Ainsi, la mesure des résidus de pesticides dans les tissus d'origine animale reste un challenge fort et qui plus est, au cœur des préoccupations environnementales actuelles.
Biotic and abiotic experimental identification of bacterial influence on Ca isotopic signatures
24 janvier 2012
Seasonal variability of element sources in two Central Siberian rivers draining high latitude permafrost dominated areas
24 janvier 2012
Les missions de Guy de Vers, co-gouverneur de la cité impériale de Besançon, auprès de Charles Quint à Tolède en 1538 et 1539
24 janvier 2012
Glyphosate and glufosinate-based herbicides: fate in soil, transfer to, and effects on land snails
24 janvier 2012
Purpose The aim of this work was to assess the transfer and effects of two widely used herbicides on the land snail Helix aspersa during long-term exposure under laboratory conditions. Materials and methods Newly hatched snails were exposed for 168 days to soil and/or food contaminated with a formulation of glyphosate (Bypass®) or glufosinate (Basta®) at the recommended field doses and also at 10-fold this dose. Results and discussion Herbicide degradation patterns showed that snails were mainly exposed during the first 28 days. The DT50 of glyphosate and glufosinate was established at 10.6 and 3.7 days, respectively. No significant effects on survival and growth were determined. Concerning genital tract maturation of the snails, exposure to herbicides tended to decrease the development of the albumen gland (inhibition of 43.5 ± 32.8%). The presence of glyphosate (6 mg kg âˆ'1 dry weight) was demonstrated in snails exposed continuously to this active ingredient at the highest concentration in their food. Conclusions These results showed a low effect of herbicides at relevant concentrations in soil but the detection of residues in tissues indicated a potential risk of transfer to the food chain. This chronic toxicity bioassay could complete the available tests to assess toxicity of contaminants, and more particularly pesticides, in soil.
Towards a GC-based microsystem for benzene and 1,3 butadiene detection: Pre-concentrator characterization
23 janvier 2012
The performance of a gas pre-concentrator/gas chromatographic column/gas sensor system was studied step by step towards benzene vapor in presence of 1,3 butadiene vapor. The pre-concentrator, based on an activated carbon of high adsorption capacity, was first characterized using a GC/FID system. By this way, the adsorption capacity of each pollutant was evaluated, first separately, then mixed with different proportions in air. It was shown that the affinity of the pre-concentrator for benzene was higher than for butadiene. Once the optimal pre-concentration parameters were adjusted, we replaced the FID detector by a metal oxide gas sensor. The use of such gas pre-concentrator allowed decreasing the detection limit of the system towards benzene in presence of butadiene by at least ten times.
Use of chemical methods to assess Cd and Pb bioavailability to the snail Cantareus aspersus: A first attempt taking into account soil characteristics
23 janvier 2012
Bioavailability is a key parameter in conditioning contaminant transfer to biota. However, in risk assessment of terrestrial contamination, insufficient attention is being paid to the influence of soil type on trace metal bioavailability. This paper addresses the influence of soil properties on the chemical availability of cadmium (Cd) and lead (Pb) (CaCl2 extraction and ionic activity) and bioavailability (accumulation kinetics) to the land snail Cantareus aspersus. Snails were exposed to nine contaminated soils differing by a single characteristic (pH or organic matter content or clay content) for 28 days. Toxicokinetic models were applied to determine metal uptake and excretion rates in snails and multivariate regression was used to relate uptake parameters to soil properties. The results showed that alkalinisation of soil and an increase of the organic matter content decreased Pb and Cd bioavailability to snails whereas kaolin clay had no significant influence. The CaCl2-extractable concentrations tended to overestimate the effects of pH when used to explain metal uptake rate. We conclude that factors other than those controlling the extractable fraction affect metal bioavailability to snails, confirming the requirement of biota measurements in risk assessment procedures.
Des contextes spatiaux de l'habitat aux processus de transformation de l'habitat rural : l'apport de la modélisation prédictive
15 janvier 2012
Des contextes spatiaux de l'habitat aux processus de transformation de l'habitat rural : l'apport de la modélisation prédictive
15 janvier 2012
Romanisation et mutations des établissements ruraux dans l'Est de la Gaule : questions et mise en perspective
15 janvier 2012
Romanisation et mutations des établissements ruraux dans l'Est de la Gaule : questions et mise en perspective
15 janvier 2012
Peuplement et territoire dans la longue durée : retour sur 25 ans d'expérience
15 janvier 2012
À l'instar des géographes, cherchant à identifi er les facteurs attractifs pour l'implantation de nos habitats afin de comprendre leur répartition dans l'espace, les archéologues et les historiens cherchent à caractériser les différentes formes d'habitat et leur organisation spatiale pour comprendre les choix d'implantation des communautés du passé. Au-delà des formes de peuplement, l'enjeu est d'approfondir notre connaissance des processus de structuration territoriale, d'appropriation de l'espace, d'organisation socio-économique et d'identification politique et culturelle. Les territoires constituant notre cadre de vie sont le résultat de tous ces processus parfois méconnus ou oubliés.
Peuplement et territoire dans la longue durée : retour sur 25 ans d'expérience
15 janvier 2012
À l'instar des géographes, cherchant à identifi er les facteurs attractifs pour l'implantation de nos habitats afin de comprendre leur répartition dans l'espace, les archéologues et les historiens cherchent à caractériser les différentes formes d'habitat et leur organisation spatiale pour comprendre les choix d'implantation des communautés du passé. Au-delà des formes de peuplement, l'enjeu est d'approfondir notre connaissance des processus de structuration territoriale, d'appropriation de l'espace, d'organisation socio-économique et d'identification politique et culturelle. Les territoires constituant notre cadre de vie sont le résultat de tous ces processus parfois méconnus ou oubliés.
Trajectoires spatio-temporelles des hommes et des établissements : contribution à la modélisation d'un système de peuplement antique
14 janvier 2012
L'étude d'un système de peuplement en archéologie a pour finalité d'appréhender, dans la longue durée, la façon dont les individus et plus généralement les communautés occupent un espace et se l'approprient. Il s'agit de chercher à identifier les phases de développement de l'habitat et de son organisation en réseau ainsi que les périodes de transition d'un système de peuplement à un autre. Dans ce type d'enquête, il convient de mettre en évidence la part respective du poids de la structure (réseau) dans l'attractivité d'un lieu, et celui des stratégies territoriales des individus ou des groupes qui modifient l'attractivité de ce lieu et conduisent à la transformation de la structure
Trajectoires spatio-temporelles des hommes et des établissements : contribution à la modélisation d'un système de peuplement antique
14 janvier 2012
L'étude d'un système de peuplement en archéologie a pour finalité d'appréhender, dans la longue durée, la façon dont les individus et plus généralement les communautés occupent un espace et se l'approprient. Il s'agit de chercher à identifier les phases de développement de l'habitat et de son organisation en réseau ainsi que les périodes de transition d'un système de peuplement à un autre. Dans ce type d'enquête, il convient de mettre en évidence la part respective du poids de la structure (réseau) dans l'attractivité d'un lieu, et celui des stratégies territoriales des individus ou des groupes qui modifient l'attractivité de ce lieu et conduisent à la transformation de la structure
Information Spatiale et Archéologie
14 janvier 2012
L'information archéologique est spatiale par nature. Quels que soient l'échelle (fouille, habitat, ville, région), le contexte (urbain, rural), le thème (peuplement, territoires, matières premières, réseaux d'échanges, culture matérielle...) ou la démarche (terrain, documentation), la localisation est une donnée fondamentale et la production de documents (carto) graphiques est une constante. Pour autant, si le positionnement dans l'espace est un préliminaire indispensable, il ne constitue pas à lui seul une réflexion sur la dimension spatiale des questions archéologiques. L'application des méthodes de l'analyse spatiale est intervenue en archéologie dès les années 1970. Elle est maintenant indissociable des Systèmes d'Information Géographique (SIG) dont les premières utilisations en archéologie ont vu le jour dans les années 1990. Dans le même temps, les archéologues ont bénéficié des progrès de la télédétection et des analyses issues des sciences de la terre. Le point de vue sur l'information spatiale développé dans cet ouvrage est résolument archéologique. Il s'agit bien sûr d'identifier précisément les caractéristiques génériques de l'information spatiale utilisable, mais surtout de distinguer ce qui est spécifique à l'archéologie ou plus généralement aux sciences historiques. Si certains considèrent que la manipulation des outils de traitement de l'information spatiale est l'affaire de spécialistes, la position des auteurs, radicalement différente, consiste à former les archéologues, qui sont les seuls à maîtriser les tenants et aboutissants de la démarche. Cet ouvrage s'adresse donc moins au spécialiste qu'à l'ensemble des acteurs qui entrent, de près ou de loin, dans la construction ou l'utilisation d'un SIG archéologique. Il s'adresse aussi à quiconque est curieux de voir comment fonctionne l'archéologie moderne.
Information Spatiale et Archéologie
14 janvier 2012
L'information archéologique est spatiale par nature. Quels que soient l'échelle (fouille, habitat, ville, région), le contexte (urbain, rural), le thème (peuplement, territoires, matières premières, réseaux d'échanges, culture matérielle...) ou la démarche (terrain, documentation), la localisation est une donnée fondamentale et la production de documents (carto) graphiques est une constante. Pour autant, si le positionnement dans l'espace est un préliminaire indispensable, il ne constitue pas à lui seul une réflexion sur la dimension spatiale des questions archéologiques. L'application des méthodes de l'analyse spatiale est intervenue en archéologie dès les années 1970. Elle est maintenant indissociable des Systèmes d'Information Géographique (SIG) dont les premières utilisations en archéologie ont vu le jour dans les années 1990. Dans le même temps, les archéologues ont bénéficié des progrès de la télédétection et des analyses issues des sciences de la terre. Le point de vue sur l'information spatiale développé dans cet ouvrage est résolument archéologique. Il s'agit bien sûr d'identifier précisément les caractéristiques génériques de l'information spatiale utilisable, mais surtout de distinguer ce qui est spécifique à l'archéologie ou plus généralement aux sciences historiques. Si certains considèrent que la manipulation des outils de traitement de l'information spatiale est l'affaire de spécialistes, la position des auteurs, radicalement différente, consiste à former les archéologues, qui sont les seuls à maîtriser les tenants et aboutissants de la démarche. Cet ouvrage s'adresse donc moins au spécialiste qu'à l'ensemble des acteurs qui entrent, de près ou de loin, dans la construction ou l'utilisation d'un SIG archéologique. Il s'adresse aussi à quiconque est curieux de voir comment fonctionne l'archéologie moderne.
Seismic slip propagation to the up-dip end of plate boundary subduction interface faults: Vitrinite reflectance geothermometry on IODP NanTroSEIZE cores
6 janvier 2012
Seismic faulting along subduction-type plate boundaries plays a fundamental role in tsunami genesis. During the Integrated Ocean Drilling Program (IODP) Nankai Trough Seismogenic Zone Experiment (NanTro SEIZE) Stage 1, the updip ends of plate boundary subduction faults were drilled and cored in the Nankai Trough (offshore Japan), where repeated large earthquakes and tsunamis have occurred, including the A.D. 1944 Tonankai (Mw = 8.1) earthquake. Samples were obtained from the frontal thrust, which connects the deep plate boundary to the seafl oor at the toe of the accretionary wedge, and from a megasplay fault that branches from the plate boundary décollement. The toe of the accretionary wedge has classically been considered aseismic, but vitrinite refl ectance geothermometry reveals that the two examined fault zones underwent localized temperatures of more than 380 C. This suggests that frictional heating occurred along these two fault zones, and implies that coseismic slip must have propagated at least one time to the updip end of the megasplay fault and to the toe of the accretionary wedge
Seismic slip propagation to the up-dip end of plate boundary subduction interface faults: Vitrinite reflectance geothermometry on IODP NanTroSEIZE cores
6 janvier 2012
Seismic faulting along subduction-type plate boundaries plays a fundamental role in tsunami genesis. During the Integrated Ocean Drilling Program (IODP) Nankai Trough Seismogenic Zone Experiment (NanTro SEIZE) Stage 1, the updip ends of plate boundary subduction faults were drilled and cored in the Nankai Trough (offshore Japan), where repeated large earthquakes and tsunamis have occurred, including the A.D. 1944 Tonankai (Mw = 8.1) earthquake. Samples were obtained from the frontal thrust, which connects the deep plate boundary to the seafl oor at the toe of the accretionary wedge, and from a megasplay fault that branches from the plate boundary décollement. The toe of the accretionary wedge has classically been considered aseismic, but vitrinite refl ectance geothermometry reveals that the two examined fault zones underwent localized temperatures of more than 380 C. This suggests that frictional heating occurred along these two fault zones, and implies that coseismic slip must have propagated at least one time to the updip end of the megasplay fault and to the toe of the accretionary wedge
Le site du Limon-Raspail à Bédoin dans le Vaucluse et le Néolithique final de moyenne vallée du Rhône
6 janvier 2012
À Bédoin dans le Vaucluse, la fouille de sauvetage urgent du Limon- Raspail dirigée par J. Cauliez en 2005 a livré, sur une surface de 250 m2, une trentaine d'aménagements creusés révélant l'existence d'un habitat relativement bien préservé et implanté en position privilégiée à près de 350 m d'altitude. Le site est daté du Néolithique final, entre 2880 et 2580 av. J.-C. Cette trentaine de structures en creux offre la vision d'une zone d'activités, là où se concentrent des foyers et des aménagements liés à la conservation, tous réutilisés comme dépotoirs. Voisin de sites éponymes à l'origine de l'identification de trois des quatre principales cultures du Néolithique final du sud-est de la France - les groupes Rhône-Ouvèze, de Fraischamp et du Nord-Vaucluse -, le gisement du Limon-Raspail ne s'accorde pas, sur le plan chronoculturel, avec l'un ou l'autre de ces ensembles. L'originalité du site peut s'expliquer par sa localisation dans une zone tampon. Il est à la limite nord des aires d'extension reconnues pour les groupes provençaux. Il s'inscrit également dans des flux de circulations alimentés par le Piémont italien ; il pourrait être enfin en liaison avec des groupes de régions plus septentrionales, tels que ceux de l'axe Saône- Rhône, dont les influences seraient perceptibles, au Néolithique final, jusque dans la moyenne vallée du Rhône.
Le site du Limon-Raspail à Bédoin dans le Vaucluse et le Néolithique final de moyenne vallée du Rhône
6 janvier 2012
À Bédoin dans le Vaucluse, la fouille de sauvetage urgent du Limon- Raspail dirigée par J. Cauliez en 2005 a livré, sur une surface de 250 m2, une trentaine d'aménagements creusés révélant l'existence d'un habitat relativement bien préservé et implanté en position privilégiée à près de 350 m d'altitude. Le site est daté du Néolithique final, entre 2880 et 2580 av. J.-C. Cette trentaine de structures en creux offre la vision d'une zone d'activités, là où se concentrent des foyers et des aménagements liés à la conservation, tous réutilisés comme dépotoirs. Voisin de sites éponymes à l'origine de l'identification de trois des quatre principales cultures du Néolithique final du sud-est de la France - les groupes Rhône-Ouvèze, de Fraischamp et du Nord-Vaucluse -, le gisement du Limon-Raspail ne s'accorde pas, sur le plan chronoculturel, avec l'un ou l'autre de ces ensembles. L'originalité du site peut s'expliquer par sa localisation dans une zone tampon. Il est à la limite nord des aires d'extension reconnues pour les groupes provençaux. Il s'inscrit également dans des flux de circulations alimentés par le Piémont italien ; il pourrait être enfin en liaison avec des groupes de régions plus septentrionales, tels que ceux de l'axe Saône- Rhône, dont les influences seraient perceptibles, au Néolithique final, jusque dans la moyenne vallée du Rhône.
Identifiability analysis of an epidemiological model in a structured population
3 janvier 2012
We investigate the parameter identifiability problem for a system of nonlinear integro-partial differential equations of transport type, representing the spread of a disease with a long infectious but undetectable period in an individual population. After obtaining the expression of the model input-output relationships, we give sufficient conditions on the initial and boundary conditions of the system that guarantee the parameter identifiability on a finite time horizon. We finally illustrate our findings with numerical simulations.
Identifiability analysis of an epidemiological model in a structured population
3 janvier 2012
We investigate the parameter identifiability problem for a system of nonlinear integro-partial differential equations of transport type, representing the spread of a disease with a long infectious but undetectable period in an individual population. After obtaining the expression of the model input-output relationships, we give sufficient conditions on the initial and boundary conditions of the system that guarantee the parameter identifiability on a finite time horizon. We finally illustrate our findings with numerical simulations.
Paleoproterozoic tectonic evolution of the Trans-North China Orogen: toward a comprehensive model.
2 janvier 2012
In this contribution we present a reconstruction of the overall lithotectonic architecture, from inner zones to external ones, of the Paleoproterozoic Trans North China Orogen, within the North China Craton. Moreover, forward thermobarometrical modeling on a kyanite-bearing gneiss yields a reliable prograde P-T-t-D path. In addition, 40Ar/39Ar dating on rocks from distinct litho-tectonic units helps us to distinguish several tectono-metamorphic events during the orogenic development. Considering these results, we propose a geodynamic model involving three cratonic blocks, namely the Western, Fuping and Eastern Blocks, separated by two oceans, the Lüliang and Taihang Oceans. The opening of oceanic basins occurred around 2.2-2.3 Ga. After the westward subductions of oceanic lithosphere, the Trans-North-China Orogen was built up through a polyphase tectonic evolution within the period 1900-1800 Ma. The first event (D1) corresponded to the emplacement of lower and upper nappes herein called the Orthogneiss-and-Volcanites Unit (OVU) and the Low-Grade-and-Mafic Unit (LGMU), respectively. The syn-metamorphic D1 deformation (1880 ± 10 Ma) is characterized by a NW-SE stretching and mineral lineation with a top-to-the SE sense of shear. During ongoing compression of the thickening orogenic crust, a second deformation event D2 (1850 ± 10 Ma) was responsible for (1) syn-anatectic lateral flow and exhumation of the orogenic root and (2) folding of the middle and upper parts of the orogenic wedge that consequently acquired a fan-type geometry. The late D3 (1830 ± 10 Ma) and D4 (1810 ± 10 Ma) events are related to late-orogenic normal and strike-slip shearing, respectively. In our present state of knowledge, the Paleoproterozoic Trans-North China Orogen might be regarded as the assemblage of two continent-continent collisional belts, both of which are characterized by nappe stacking accommodated by top-to-the E/SE ductile shearing. Continental subduction, crustal thickening, partial melting of overthickened crust, exhumation of HP rocks and deposition of syn-orogenic detrital basins are typical features of modern collisional-type orogens.
Initiation à la géologie du massif du Jura Premier bilan de l'action " Montagnes du Jura "
2 janvier 2012
Initiation à la géologie du massif du Jura Premier bilan de l'action " Montagnes du Jura "
2 janvier 2012
Long-term effects of grazing exclusion on aboveground and belowground plant species diversity in a steppe of the Loess Plateau, China
22 décembre 2011
Background and aims - Livestock grazing exclusion was widely used to manage degraded grassland ecosystems, but little is known on the effects of long-term grazing exclusion on aboveground and belowground species diversity of the steppe vegetation in China. Material and methods - The species composition of the aboveground vegetation and the soil seed bank were examined on sites after a 25-year grazing exclusion in a typical steppe on the Loess Plateau, NW China. Key results - Results showed that long-term grazing exclusion significantly improved vegetation cover, biomass and aboveground species evenness. Long-term grazing exclusion significantly increased species richness and seed density in the soil seed bank, but significantly decreased belowground species evenness. The seeds were mainly present in the litter and the topsoil (0-5 cm), accounting for about 76% of the total seed number. Exclusion of grazing significantly decreased seed depletion in soil seed bank from April to July as compared to grazed sites. The Sørensen similarity index between aboveground and belowground species composition was low in the typical steppe, and long-term grazing exclusion did not significantly improve this similarity. Conclusion - Our results suggest that long-term grazing exclusion can significantly improve both aboveground and belowground species diversity in the steppe vegetation of the Loess Plateau, but has little or no effect on the similarity in composition between the two compartments.
Long-term effects of grazing exclusion on aboveground and belowground plant species diversity in a steppe of the Loess Plateau, China
22 décembre 2011
Background and aims - Livestock grazing exclusion was widely used to manage degraded grassland ecosystems, but little is known on the effects of long-term grazing exclusion on aboveground and belowground species diversity of the steppe vegetation in China. Material and methods - The species composition of the aboveground vegetation and the soil seed bank were examined on sites after a 25-year grazing exclusion in a typical steppe on the Loess Plateau, NW China. Key results - Results showed that long-term grazing exclusion significantly improved vegetation cover, biomass and aboveground species evenness. Long-term grazing exclusion significantly increased species richness and seed density in the soil seed bank, but significantly decreased belowground species evenness. The seeds were mainly present in the litter and the topsoil (0-5 cm), accounting for about 76% of the total seed number. Exclusion of grazing significantly decreased seed depletion in soil seed bank from April to July as compared to grazed sites. The Sørensen similarity index between aboveground and belowground species composition was low in the typical steppe, and long-term grazing exclusion did not significantly improve this similarity. Conclusion - Our results suggest that long-term grazing exclusion can significantly improve both aboveground and belowground species diversity in the steppe vegetation of the Loess Plateau, but has little or no effect on the similarity in composition between the two compartments.
Heterogeneity of soil carbon pools and fluxes in a channelized and a restored floodplain section (Thur River, Switzerland)
22 décembre 2011
Heterogeneity of soil carbon pools and fluxes in a channelized and a restored floodplain section (Thur River, Switzerland)
22 décembre 2011
Frequency and intensity of high-altitude floods over the last 3.5 ka in northwestern French Alps (Lake Anterne)
19 décembre 2011
In central Western Europe, several studies have shown that colder Holocene periods, such as the Little Ice Age, also correspond to wet periods. However, in mountain areas which are highly sensitive to erosion processes and where precipitation events can be localized, past evolution of hydrological activity might be more complicated. To assess these past hydrological changes, a paleolimnological approach was applied on a 13.4-m-long sediment core taken in alpine Lake Anterne (2063 m asl) and representing the last 3.5 ka. Lake sedimentation is mainly composed of flood deposits triggered by precipitation events. Sedimentological and geochemical analyses show that floods were more frequent during cold periods while high-intensity flood events occurred preferentially during warmer periods. In mild temperature conditions, both flood patterns are present. This underlines the complex relationship between flood hazards and climatic change in mountain areas. During the warmer and/or dryer times of the end of Iron Age and the Roman Period, both the frequency and intensity of floods increased. This is interpreted as an effect of human-induced clearing for grazing activities and reveals that anthropogenic interferences must be taken into account when reconstructing climatic signals from natural archives.
Frequency and intensity of high-altitude floods over the last 3.5 ka in northwestern French Alps (Lake Anterne)
19 décembre 2011
In central Western Europe, several studies have shown that colder Holocene periods, such as the Little Ice Age, also correspond to wet periods. However, in mountain areas which are highly sensitive to erosion processes and where precipitation events can be localized, past evolution of hydrological activity might be more complicated. To assess these past hydrological changes, a paleolimnological approach was applied on a 13.4-m-long sediment core taken in alpine Lake Anterne (2063 m asl) and representing the last 3.5 ka. Lake sedimentation is mainly composed of flood deposits triggered by precipitation events. Sedimentological and geochemical analyses show that floods were more frequent during cold periods while high-intensity flood events occurred preferentially during warmer periods. In mild temperature conditions, both flood patterns are present. This underlines the complex relationship between flood hazards and climatic change in mountain areas. During the warmer and/or dryer times of the end of Iron Age and the Roman Period, both the frequency and intensity of floods increased. This is interpreted as an effect of human-induced clearing for grazing activities and reveals that anthropogenic interferences must be taken into account when reconstructing climatic signals from natural archives.
87Sr/86Sr and 18O/16O ratios of clays from a hydrothermal area near the Galapagos rift as records of origin, crystallization temperature and fluid composition
16 décembre 2011
Strontium and O isotope compositions of green clay minerals from sediment cores of three boreholes drilled into (sites 424A and 509B) and close to a hydrothermal mound (site 424B) near the Galapagos Spreading Center (DSDP Legs 54 and 70) were determined. The green clays consist mostly of a transition from Fesmectite (nontronite) to glauconite. 87Sr/86Sr ratios were measured on clay size-fractions after gentle acid leaching and on the recovered leachates from different samples. The 87Sr/86Sr ratios of the clay residues from both the 424A and B sites are well below the modern seawater value, which points consistently to precipitation from hydrothermal fluids that contained variable amounts of seawater, even away from mound. However, most of the clay residues from mound site 509B have 87Sr/86Sr ratios significantly above the seawater value, suggesting the occurrence of a detrital component together with the new authigenic particles. The clay minerals of the hydrothermal mound are mixed with detrital components, and that of the sample taken outside but near the mound as a reference for the surrounding oceanic environment, yields a hydrothermal signature. Crystallization temperatures of the clays range from 32 to 63 °C assuming a δ18O value of +2.2‰ for the mineralizing fluids. Hydrothermal fluids generated in the underlying oceanic crust, mixed in varied proportions with ambient seawater and migrated into beds of the mound in a sequence of recurrent processes that ultimately resulted in the formation of the observed clay minerals. No significant temperature differences were detected for crystallization of the K-rich glauconite and K-depleted nontronite. The 87Sr/86Sr ratios of the Sr leached off the clay particles are near the value of modern seawater, inferring a progressive replacement of the hydrothermal fluids by seawater in the pore space of the mound sediments.
87Sr/86Sr and 18O/16O ratios of clays from a hydrothermal area near the Galapagos rift as records of origin, crystallization temperature and fluid composition
16 décembre 2011
Strontium and O isotope compositions of green clay minerals from sediment cores of three boreholes drilled into (sites 424A and 509B) and close to a hydrothermal mound (site 424B) near the Galapagos Spreading Center (DSDP Legs 54 and 70) were determined. The green clays consist mostly of a transition from Fesmectite (nontronite) to glauconite. 87Sr/86Sr ratios were measured on clay size-fractions after gentle acid leaching and on the recovered leachates from different samples. The 87Sr/86Sr ratios of the clay residues from both the 424A and B sites are well below the modern seawater value, which points consistently to precipitation from hydrothermal fluids that contained variable amounts of seawater, even away from mound. However, most of the clay residues from mound site 509B have 87Sr/86Sr ratios significantly above the seawater value, suggesting the occurrence of a detrital component together with the new authigenic particles. The clay minerals of the hydrothermal mound are mixed with detrital components, and that of the sample taken outside but near the mound as a reference for the surrounding oceanic environment, yields a hydrothermal signature. Crystallization temperatures of the clays range from 32 to 63 °C assuming a δ18O value of +2.2‰ for the mineralizing fluids. Hydrothermal fluids generated in the underlying oceanic crust, mixed in varied proportions with ambient seawater and migrated into beds of the mound in a sequence of recurrent processes that ultimately resulted in the formation of the observed clay minerals. No significant temperature differences were detected for crystallization of the K-rich glauconite and K-depleted nontronite. The 87Sr/86Sr ratios of the Sr leached off the clay particles are near the value of modern seawater, inferring a progressive replacement of the hydrothermal fluids by seawater in the pore space of the mound sediments.
Les parasites dans les lacs nord alpins au Néolithique (3900-2900 BC) et nouvelles données dans la détection des paléoantigènes de Protozoa.
15 décembre 2011
Les parasites dans les lacs nord alpins au Néolithique (3900-2900 BC) et nouvelles données dans la détection des paléoantigènes de Protozoa.
15 décembre 2011
Dynamics of cholera outbreaks in great lakes region of Africa, 1978-2008.
10 décembre 2011
Cholera outbreaks have occurred in Burundi, Rwanda, Democratic Republic of Congo, Tanzania, Uganda, and Kenya almost every year since 1977-1978, when the disease emerged in these countries. We used a multiscale, geographic information system-based approach to assess the link between cholera outbreaks, climate, and environmental variables. We performed time-series analyses and field investigations in the main affected areas. Results showed that cholera greatly increased during El Nino warm events (abnormally warm El Ninos) but decreased or remained stable between these events. Most epidemics occurred in a few hotspots in lakeside areas, where the weekly incidence of cholera varied by season, rainfall, fluctuations of plankton, and fishing activities. During lull periods, persistence of cholera was explained by outbreak dynamics, which suggested a metapopulation pattern, and by endemic foci around the lakes. These links between cholera outbreaks, climate, and lake environments need additional, multidisciplinary study.
Dynamics of cholera outbreaks in great lakes region of Africa, 1978-2008.
10 décembre 2011
Cholera outbreaks have occurred in Burundi, Rwanda, Democratic Republic of Congo, Tanzania, Uganda, and Kenya almost every year since 1977-1978, when the disease emerged in these countries. We used a multiscale, geographic information system-based approach to assess the link between cholera outbreaks, climate, and environmental variables. We performed time-series analyses and field investigations in the main affected areas. Results showed that cholera greatly increased during El Nino warm events (abnormally warm El Ninos) but decreased or remained stable between these events. Most epidemics occurred in a few hotspots in lakeside areas, where the weekly incidence of cholera varied by season, rainfall, fluctuations of plankton, and fishing activities. During lull periods, persistence of cholera was explained by outbreak dynamics, which suggested a metapopulation pattern, and by endemic foci around the lakes. These links between cholera outbreaks, climate, and lake environments need additional, multidisciplinary study.
Vegetation response to obliquity and precession forcing during the Mid Pleistocene Transition in Western Mediterranean region (ODP Site 976)
8 décembre 2011
The ODP leg 161 Site 976 (Alboran Sea) is a deep-sea section sampled at a water depth of 1108 m in the Western Mediterranean Sea. Pollen analysis provides a vegetation and climate record of the Mid Pleistocene Transition (MPT), roughly one million years ago. The age-model tied to biostratigraphic events was revised by aligning the pollen climate index (PCI) to Mediterranean (KC01b) and global (LR04) oxygen isotope records. The studied time slice spans the interval w1.09 Ma (MIS 31) to w0.90 Ma (MIS 23). Across this interval, past phytogeography of nowadays extinct taxa, which were rare, allows a successful application of the modern analogues technique (MAT) to quantitative climate reconstructions for theMPT. Five, long-term, obliquity-related vegetation successions (O1 to O5), and eight short-term, precessionrelated vegetation successions (P1 to P8) are observed within the studied interval. These vegetation successions, regardless of their duration, show the same pattern: the progressive replacement of temperate trees by mountainous taxa, and then by herbs and steppe maxima. Precession-related successions correspond, therefore, to as dramatic vegetation changes as those driven by obliquity, including a final steppe phase under deteriorated climate conditions. Wavelet analysis of the PCI record shows that theWestern Mediterranean experienced a shift at 1.01 Ma from precession-dominated frequencies (1.05e1.01 Ma) to obliquity-dominated frequencies (1.01e0.9 Ma). There is, therefore, an apparent discrepancy between wavelet analysis results and vegetation dynamic analysis (which suggests that obliquity and precession are recorded throughout the entire studied interval). This discrepancy could result from the fact that the PCI record sums, somehow, similar vegetation changes (wet to dry) occurring at different periodicities. Such a complex vegetation dynamics is mathematically rendered through a single parameter (i.e. principal component), which does not successfully catch the subtle combinations of variability occurring at two close periodicities. Furthermore, the pollen-inferred Early Pleistocene vegetation dynamic (and climate) of the Western Mediterranean region does not show a decrease of the obliquity response relative to the precession response at the onset of the MPT.
Vegetation response to obliquity and precession forcing during the Mid Pleistocene Transition in Western Mediterranean region (ODP Site 976)
8 décembre 2011
The ODP leg 161 Site 976 (Alboran Sea) is a deep-sea section sampled at a water depth of 1108 m in the Western Mediterranean Sea. Pollen analysis provides a vegetation and climate record of the Mid Pleistocene Transition (MPT), roughly one million years ago. The age-model tied to biostratigraphic events was revised by aligning the pollen climate index (PCI) to Mediterranean (KC01b) and global (LR04) oxygen isotope records. The studied time slice spans the interval w1.09 Ma (MIS 31) to w0.90 Ma (MIS 23). Across this interval, past phytogeography of nowadays extinct taxa, which were rare, allows a successful application of the modern analogues technique (MAT) to quantitative climate reconstructions for theMPT. Five, long-term, obliquity-related vegetation successions (O1 to O5), and eight short-term, precessionrelated vegetation successions (P1 to P8) are observed within the studied interval. These vegetation successions, regardless of their duration, show the same pattern: the progressive replacement of temperate trees by mountainous taxa, and then by herbs and steppe maxima. Precession-related successions correspond, therefore, to as dramatic vegetation changes as those driven by obliquity, including a final steppe phase under deteriorated climate conditions. Wavelet analysis of the PCI record shows that theWestern Mediterranean experienced a shift at 1.01 Ma from precession-dominated frequencies (1.05e1.01 Ma) to obliquity-dominated frequencies (1.01e0.9 Ma). There is, therefore, an apparent discrepancy between wavelet analysis results and vegetation dynamic analysis (which suggests that obliquity and precession are recorded throughout the entire studied interval). This discrepancy could result from the fact that the PCI record sums, somehow, similar vegetation changes (wet to dry) occurring at different periodicities. Such a complex vegetation dynamics is mathematically rendered through a single parameter (i.e. principal component), which does not successfully catch the subtle combinations of variability occurring at two close periodicities. Furthermore, the pollen-inferred Early Pleistocene vegetation dynamic (and climate) of the Western Mediterranean region does not show a decrease of the obliquity response relative to the precession response at the onset of the MPT.
Holocene fire regime changes from multiple-site sedimentary charcoal analyses in the Lourdes basin (Pyrenees, France)
8 décembre 2011
One lake and three peat bogs from the Lourdes glacial basin (France) were used for macrocharcoal analyses and fire frequency reconstruction over the entire Holocene (11700 years). The chronology was based upon thirty-three 14C AMS dates. Comparison of the distribution of both CHarcoal Accumulation Rate (CHAR) and fire return intervals showed that charcoal accumulation significantly differs between the lake and the peat bogs, but that frequency calculation overcomes the disparity between these site types. A composite frequency was built from the four individual records to assess regional versus local variability and fire regime controls by comparisons with regional fire activity, Holocene climatic oscillations and vegetation history. The millennial variability can be depicted as follows: relatively high frequency between 8000 and 5000 cal a BP (up to 5 fires/500 yrs), relatively low frequency between 5000 and 3000 cal a BP (down to 0 fires/500 yrs), and an increase between 3000 and 500 cal a BP (up to 4 fires/500 yrs). From 8000 to 5000 cal a BP, fire frequency displays strong synchrony between sites and appears to be mostly driven by increased summer temperature characterizing the Holocene Thermal Maximum (HTM). On the contrary, during the last 3000 years fire frequency was heterogeneous between sites and most probably human-driven. However, higher frequency at the millennial scale during the mid-Holocene strongly suggests that the perception of human-driven fire regime depends on the strength of natural controls.
Holocene fire regime changes from multiple-site sedimentary charcoal analyses in the Lourdes basin (Pyrenees, France)
8 décembre 2011
One lake and three peat bogs from the Lourdes glacial basin (France) were used for macrocharcoal analyses and fire frequency reconstruction over the entire Holocene (11700 years). The chronology was based upon thirty-three 14C AMS dates. Comparison of the distribution of both CHarcoal Accumulation Rate (CHAR) and fire return intervals showed that charcoal accumulation significantly differs between the lake and the peat bogs, but that frequency calculation overcomes the disparity between these site types. A composite frequency was built from the four individual records to assess regional versus local variability and fire regime controls by comparisons with regional fire activity, Holocene climatic oscillations and vegetation history. The millennial variability can be depicted as follows: relatively high frequency between 8000 and 5000 cal a BP (up to 5 fires/500 yrs), relatively low frequency between 5000 and 3000 cal a BP (down to 0 fires/500 yrs), and an increase between 3000 and 500 cal a BP (up to 4 fires/500 yrs). From 8000 to 5000 cal a BP, fire frequency displays strong synchrony between sites and appears to be mostly driven by increased summer temperature characterizing the Holocene Thermal Maximum (HTM). On the contrary, during the last 3000 years fire frequency was heterogeneous between sites and most probably human-driven. However, higher frequency at the millennial scale during the mid-Holocene strongly suggests that the perception of human-driven fire regime depends on the strength of natural controls.
Etude palynologique
7 décembre 2011
Sur le site de Courrendlin-Vers la Vieille Eglise, deux séries d'échantillons ont été prélevés dans un paléo-chenal.
Etude palynologique
7 décembre 2011
Sur le site de Courrendlin-Vers la Vieille Eglise, deux séries d'échantillons ont été prélevés dans un paléo-chenal.
A 2500 year record of natural and anthropogenic soil erosion in South Greenland
5 décembre 2011
The environmental impact of the Norse landnám in Greenland has been studied extensively. But to date, no study has quantified the soil erosion that Norse agricultural practices are believed to have caused. To resolve this problem, a high resolution sedimentary record from Lake Igaliku in South Greenland is used to quantitatively reconstruct 2500 years of soil erosion driven by climate and historical land use. An accurate chronology allows for the estimation of detritic fluxes and their uncertainties. Land clearance and the introduction of grazing livestock by the Norse around 1010 AD caused an acceleration of soil erosion up to 8 mm/century in 1180 AD which is two-fold higher than the natural pre-landnám background. From 1335 AD to the end of the Norse Eastern Settlement (in the mid-fifteenth century), the vegetation began to recover from initial disturbance and soil erosion decreased. After an initial phase of modern sheep breeding similar to the medieval one, the mechanization of agriculture in the 1980s caused an unprecedented soil erosion rate of up to 21 mm /century, five times the pre anthropogenic levels. Independently, a suite of biological and geochemical proxies (including Ti and diatom concentrations, C:N ratio, 13C and 15N of organic matter) confirm that the medieval and modern anthropogenic erosion far exceeds any natural erosion over the last 2500 years. Our findings question the veracity of the catastrophic scenario of overgrazing and land degradation considered to have been the major factor responsible for Norse settlement demise. They also shed light on the sustainability of modern practices and their consequences for the future of agriculture in Greenland.
Microtectonic and geochemical characterization of thrusting in a foreland basin: Example of the South-Pyrenean orogenic wedge (Spain)
25 novembre 2011
In orogenic systems, thrust faults play a major role in stacking different tectonic units and may act as conduits for the expulsion of large amounts of fluid of different origins (metamorphic, diagenetic, meteoric). This study focuses on the Monte Perdido thrust unit emplaced in the Paleogene Jaca thrust-sheet-top basin, in the SW-central Pyrenees. We aim to decipher the mechanisms and P-T conditions of deformation in fault zones and characterize the related fluid involvement, through combined microstructural, geochemical and microthermometry analyses. Two thrust faults cutting platform limestones, marls and siliciclastic turbidites of the lower part of the basin-fill (Paleocene-lower Eocene) have been studied. The fault zones are characterized by metre-thick shear zones with highly deformed, foliated clay-rich sediments. Foliation is underlined by preferentially oriented phyllosilicates. Several generations of shear and extension calcite, quartz and chlorite-bearing veins attest to fluid-rock interactions during a multi-stage deformation. Microstructural observations and stable isotope analyses on calcite from veins and host sediments suggest that deformation was aseismic and dominated by diffusive mass transfer from pressure solution sites along cleavage and stylolites to the precipitation sites in veins, with mineralizing fluids in equilibrium with the host sediments. Our results suggest an essentially closed hydrologic system, and imply the absence of significant fluid flow along the studied fault zones. Microthermometric study on fluid inclusions present in calcite and quartz veins, and calcite-quartz oxygen isotopic fractionation determined for the first generation shear veins, allow a geothermal gradient of 34 degrees C/km to be estimated. Analytical results demonstrate an evolution of the fault zones in three stages. The first stage was related to the emplacement of the Monte Perdido thrust unit during the middle Eocene at a temperature of similar to 208 degrees C and a burial depth of similar to 5.7 km. The second stage corresponds to a fault reactivation at a temperature of similar to 240 degrees C and a burial depth of similar to 6.5 km. The latter deformation may have been related to folding of the Monte Perdido thrust unit during the emplacement of the underlying Gavarnie thrust unit during the late Eocene-early Oligocene, with deeper burial resulting from aggradation of the thrust-sheet-top basin-fill. The last event corresponds to the formation of a dilatant vein system likely related to the exhumation of the massif.
Microtectonic and geochemical characterization of thrusting in a foreland basin: Example of the South-Pyrenean orogenic wedge (Spain)
25 novembre 2011
In orogenic systems, thrust faults play a major role in stacking different tectonic units and may act as conduits for the expulsion of large amounts of fluid of different origins (metamorphic, diagenetic, meteoric). This study focuses on the Monte Perdido thrust unit emplaced in the Paleogene Jaca thrust-sheet-top basin, in the SW-central Pyrenees. We aim to decipher the mechanisms and P-T conditions of deformation in fault zones and characterize the related fluid involvement, through combined microstructural, geochemical and microthermometry analyses. Two thrust faults cutting platform limestones, marls and siliciclastic turbidites of the lower part of the basin-fill (Paleocene-lower Eocene) have been studied. The fault zones are characterized by metre-thick shear zones with highly deformed, foliated clay-rich sediments. Foliation is underlined by preferentially oriented phyllosilicates. Several generations of shear and extension calcite, quartz and chlorite-bearing veins attest to fluid-rock interactions during a multi-stage deformation. Microstructural observations and stable isotope analyses on calcite from veins and host sediments suggest that deformation was aseismic and dominated by diffusive mass transfer from pressure solution sites along cleavage and stylolites to the precipitation sites in veins, with mineralizing fluids in equilibrium with the host sediments. Our results suggest an essentially closed hydrologic system, and imply the absence of significant fluid flow along the studied fault zones. Microthermometric study on fluid inclusions present in calcite and quartz veins, and calcite-quartz oxygen isotopic fractionation determined for the first generation shear veins, allow a geothermal gradient of 34 degrees C/km to be estimated. Analytical results demonstrate an evolution of the fault zones in three stages. The first stage was related to the emplacement of the Monte Perdido thrust unit during the middle Eocene at a temperature of similar to 208 degrees C and a burial depth of similar to 5.7 km. The second stage corresponds to a fault reactivation at a temperature of similar to 240 degrees C and a burial depth of similar to 6.5 km. The latter deformation may have been related to folding of the Monte Perdido thrust unit during the emplacement of the underlying Gavarnie thrust unit during the late Eocene-early Oligocene, with deeper burial resulting from aggradation of the thrust-sheet-top basin-fill. The last event corresponds to the formation of a dilatant vein system likely related to the exhumation of the massif.
Possible Quaternary growth of a hidden anticline at the front of the Jura fold-and-thrust belt: geomorphological constraints from the Forêt de Chaux area, France
24 novembre 2011
This study presents new constraints for Plio-Quaternary (post-2.4 Ma to present-day) anticline growth along the frontal zone of the Jura fold-and-thrust belt, in the Forêt de Chaux area, located 30 km SW of Besançon. The Forêt de Chaux area consists of a N080°E-elongated depression bordered by the Doubs and Loue rivers to the north and south respectively, and filled with Sundgau-type Pliocene alluvial deposits. The upper surface of the Pliocene deposits between the Loue and Doubs rivers is marked by a N065°E-trending ridge crossing the depression in a median position. A differential uplift along this ridge, post-dating the deposition of the gravels (2.4 Ma), is suggested by several geomorphological observations such as the opposite river migration on each side of the ridge as well as variations of drainage geometry and incision intensity. Geological and geophysical subsurface data indicate that the ridge roughly coincides with the axis of an anticline hidden beneath the Pliocene deposits. The observed uplift is presumably related to a post-2.4 Ma anticline growth. The fact that the azimuth of the hidden anticline axis is parallel to the strike of deep-seated Late Paleozoic basement faults and not to the local strike of the thin-skinned Jura structures indicates that the inferred post-Pliocene deformation could possibly be an expression of a recent thick-skinned deformation of the basement of the northern Alpine foreland. The focal depth (15 km) of the February 24th, 2004, Besançon earthquake supports the hypothesis of a basement fault reactivation.
Les mutations du réseau routier de la période laténienne au début de la période impériale : apport des données archéologiques récentes
8 novembre 2011
La question des infrastructures routières (et plus spécifiquement des mutations imposées par la mise en place de nouveaux axes militaires dans les années qui ont suivi la conquête) est l'un des phénomènes les plus communément utilisés pour illustrer le rôle moteur qu'aurait joué l'armée dans le processus de romanisation. Si le dossier historique a depuis longtemps fait l'objet d'une lecture critique (Grenier 1934 ; Collectif 1983), les confrontations avec les données archéologiques restent largement en deçà de ce qu'exigerait un tel sujet d'étude. Les travaux récents, qui restent rares, s'appuient généralement sur un dossier élaboré au cours du xixe siècle, alors que les agents voyers, relayés par les sociétés savantes, décrivaient partout le tracé des voies dites "romaines". La tradition archéologique française, qui repose encore aujourd'hui sur ce corpus, isole depuis cette période deux strates chronologiquement différentes dans ce réseau supposé antique (Chevallier 1962). La première, antérieure à la conquête, formerait l'architecture régionale et locale du réseau gallo-romain. La seconde, adoptant des caractères hérités de l'ingénierie militaire romaine, correspondrait au réseau supra régional, puisant dans les décisions d'Agrippa la trame générale de son organisation. À cette dimension chronologique on ajoute généralement une dimension hiérarchique, fondée sur le texte de Siculus Flaccus (Laurence 1999). A. Grenier, suivi en cela par la tradition historiographique française (Jullian 1923 ; Thévenot 1969 ; Chevallier 1963 ; Cloppet 1996) propose de réserver aux vieilles routes gauloises le statut de voies vicinales (viae vicinales), à la charge des collectivités locales, et aux créations romaines celui de voies publiques (viae publicae). Cette proposition, qui se déduit des travaux de C. Jullian et d'A. Grenier, semble trop simpliste et doit être confrontée avec les données livrées par les multiples opérations archéologiques récentes...
Les mutations du réseau routier de la période laténienne au début de la période impériale : apport des données archéologiques récentes
8 novembre 2011
La question des infrastructures routières (et plus spécifiquement des mutations imposées par la mise en place de nouveaux axes militaires dans les années qui ont suivi la conquête) est l'un des phénomènes les plus communément utilisés pour illustrer le rôle moteur qu'aurait joué l'armée dans le processus de romanisation. Si le dossier historique a depuis longtemps fait l'objet d'une lecture critique (Grenier 1934 ; Collectif 1983), les confrontations avec les données archéologiques restent largement en deçà de ce qu'exigerait un tel sujet d'étude. Les travaux récents, qui restent rares, s'appuient généralement sur un dossier élaboré au cours du xixe siècle, alors que les agents voyers, relayés par les sociétés savantes, décrivaient partout le tracé des voies dites "romaines". La tradition archéologique française, qui repose encore aujourd'hui sur ce corpus, isole depuis cette période deux strates chronologiquement différentes dans ce réseau supposé antique (Chevallier 1962). La première, antérieure à la conquête, formerait l'architecture régionale et locale du réseau gallo-romain. La seconde, adoptant des caractères hérités de l'ingénierie militaire romaine, correspondrait au réseau supra régional, puisant dans les décisions d'Agrippa la trame générale de son organisation. À cette dimension chronologique on ajoute généralement une dimension hiérarchique, fondée sur le texte de Siculus Flaccus (Laurence 1999). A. Grenier, suivi en cela par la tradition historiographique française (Jullian 1923 ; Thévenot 1969 ; Chevallier 1963 ; Cloppet 1996) propose de réserver aux vieilles routes gauloises le statut de voies vicinales (viae vicinales), à la charge des collectivités locales, et aux créations romaines celui de voies publiques (viae publicae). Cette proposition, qui se déduit des travaux de C. Jullian et d'A. Grenier, semble trop simpliste et doit être confrontée avec les données livrées par les multiples opérations archéologiques récentes...
A historical view of alveolar echinococcosis, 160 years after the discovery of the first case in humans: part 1. What have we learnt on the distribution of the disease and on its parasitic agent?
3 novembre 2011
Since the first 2 cases observed in Southern Germany and the correct identification of a parasite at the origin of the disease by the famous scientist Rudolf Virchow in 1855, the borders of the endemic area of alveolar echinococcosis (AE) have never stopped to expand. The parasite was successively recognized in Switzerland, then in Russia, Austria and France which were long considered as the only endemic areas for the disease. Cases were disclosed in Turkey in 1939; then much attention was paid to Alaska and to Hokkaido, in Japan. The situation totally changed in 1991 after the recognition of the Chinese endemic areas by the international community of scientists. The world map was completed in the beginning of the 21st century by the identification of AE in most of the countries of central/eastern Europe and Baltic States, and by the recognition of cases in central Asia. Up to now, the disease has however never been reported in the South hemisphere and in the United Kingdom. In the mid-1950s, demonstration by Rausch and Schiller in Alaska, and by Vogel in Germany, of the distinction between 2 parasite species responsible respectively for cystic echinococcosis ("hydatid disease") and AE put an end to the long-lasting debate between the "dualists", who believed in that theory which eventually proved to be true, and the "unicists", who believed in a single species responsible for both diseases. At the end of the 20th century, molecular biology fully confirmed the "dualist" theory while adding several new species to the initially described E. granulosus; within the past decade, it also confirmed that little variation existed within E. multilocularis species, and that AE-looking infection in some intermediate animal hosts on the Tibetan plateau was indeed due to a new species, distinct from E. multilocularis, named E. shiquicus. Since the 1970s, the unique ecological interactions between the landscape, the hosts, and E. multilocularis have progressively been delineated. The important role of the rodent/lagomorph reservoir size for the maintenance of the parasite cycle has been recognized within the last 2 decades of the 20th century. And the discovery of a close relationship between high densities of small mammals and particularities in land use by agriculture/forestry has stressed the responsibility of political/economic decisions on the contamination pressure. Urbanization of foxes in Europe and Japan and the major role of dogs in China represent the new deals at the beginning of the 21st century regarding definitive hosts and prevention measures.
A historical view of alveolar echinococcosis, 160 years after the discovery of the first case in humans: part 1. What have we learnt on the distribution of the disease and on its parasitic agent?
3 novembre 2011
Since the first 2 cases observed in Southern Germany and the correct identification of a parasite at the origin of the disease by the famous scientist Rudolf Virchow in 1855, the borders of the endemic area of alveolar echinococcosis (AE) have never stopped to expand. The parasite was successively recognized in Switzerland, then in Russia, Austria and France which were long considered as the only endemic areas for the disease. Cases were disclosed in Turkey in 1939; then much attention was paid to Alaska and to Hokkaido, in Japan. The situation totally changed in 1991 after the recognition of the Chinese endemic areas by the international community of scientists. The world map was completed in the beginning of the 21st century by the identification of AE in most of the countries of central/eastern Europe and Baltic States, and by the recognition of cases in central Asia. Up to now, the disease has however never been reported in the South hemisphere and in the United Kingdom. In the mid-1950s, demonstration by Rausch and Schiller in Alaska, and by Vogel in Germany, of the distinction between 2 parasite species responsible respectively for cystic echinococcosis ("hydatid disease") and AE put an end to the long-lasting debate between the "dualists", who believed in that theory which eventually proved to be true, and the "unicists", who believed in a single species responsible for both diseases. At the end of the 20th century, molecular biology fully confirmed the "dualist" theory while adding several new species to the initially described E. granulosus; within the past decade, it also confirmed that little variation existed within E. multilocularis species, and that AE-looking infection in some intermediate animal hosts on the Tibetan plateau was indeed due to a new species, distinct from E. multilocularis, named E. shiquicus. Since the 1970s, the unique ecological interactions between the landscape, the hosts, and E. multilocularis have progressively been delineated. The important role of the rodent/lagomorph reservoir size for the maintenance of the parasite cycle has been recognized within the last 2 decades of the 20th century. And the discovery of a close relationship between high densities of small mammals and particularities in land use by agriculture/forestry has stressed the responsibility of political/economic decisions on the contamination pressure. Urbanization of foxes in Europe and Japan and the major role of dogs in China represent the new deals at the beginning of the 21st century regarding definitive hosts and prevention measures.
Une seconde dédicace du centurion G. Appius Capito découverte dans le bois communal de Pont-à-Mousson (Meurthe-et-Moselle)
2 novembre 2011
Une seconde dédicace du centurion G. Appius Capito découverte dans le bois communal de Pont-à-Mousson (Meurthe-et-Moselle)
2 novembre 2011
Airborne laser scanning for the management of archaeological sites in Lorraine (France)
2 novembre 2011
This paper reports on two study areas in Lorraine recorded with airborne laser scanning (or LiDAR) for management of archeological sites. The first, in the large Haye Forest near Nancy, recorded a very broad range of monuments of all types and periods, from which it was possible to propose measures to protect the sites during forest work. The second was undertaken within the framework of the construction of the second phase of the high speed rail link between Paris and Strasbourg and illustrates the contribution of this method for in development of (?) preventive archaeology to all the phases of the process, but also its limits.
Airborne laser scanning for the management of archaeological sites in Lorraine (France)
2 novembre 2011
This paper reports on two study areas in Lorraine recorded with airborne laser scanning (or LiDAR) for management of archeological sites. The first, in the large Haye Forest near Nancy, recorded a very broad range of monuments of all types and periods, from which it was possible to propose measures to protect the sites during forest work. The second was undertaken within the framework of the construction of the second phase of the high speed rail link between Paris and Strasbourg and illustrates the contribution of this method for in development of (?) preventive archaeology to all the phases of the process, but also its limits.
interactions initiales entre cellules dendritiques et micro-organismes impliqués dans les pneumopathies d'hypersensibilité
24 octobre 2011
Interactions initiales entre cellules dendritiques et micro-organismes impliqués dans les pneumopathies d'hypersensibilité. BELLANGER AP (1,2), PALLANDRE JR (3), BORG C (3), LOEFFERT S (1,2), REBOUX G (1,2), DALPHIN JC (2,4), MILLON L (1,2) 1 Parasitologie-Mycologie CHU J Minjoz Besançon, 2 Unité de Recherche " Chrono-Environnement "-CNRS 6249- Université de Franche Comté Besançon, 3 Immunologie, EFS Bourgogne Franche Comte Besançon, 4 Pneumologie CHU J Minjoz Besançon Mail : apbellanger@chu-besancon.fr Introduction Les pneumopathies d'hypersensibilité (PHS) sont des maladies immuno-allergiques dues à l'inhalation répétée de fortes concentrations d'antigéniques fongiques ou bactériens. Les PHS se caractérisent par une alvéolite lymphocytaire. Les cellules dendritiques jouent un rôle prépondérant dans l'activation et la différentiation des lymphocytes lors de l'inhalation d'allergènes. L'objectif de ce travail est d'étudier les interactions initiales entre les cellules dendritiques et les principaux micro-organismes impliqués dans les PHS (Saccharopolyspora rectivirgula, Wallemia sebi, Eurotium amstelodami et Mycobacterium immunogenum). Méthodes Des cellules dendritiques humaines ont été exposées pendant 24 h à des extraits totaux de S. rectivirgula, W. sebi, E. amstelodami et M. immunogenum. L'activation phénotypique des cellules dendritiques a étéévaluée par cytométrie de flux (CD86, CD83 et CD80). Les interleukines (IL) IL-8, l'IL-23, l'IL-12 et l'IL-10 ont été dosées par ELISA dans les surnageants. L'activation fonctionnelle des cellules dendritiques a étéévaluée par mise en contact avec des lymphocytes (MLR). Résultats Chaque micro-organismes testés a induit une activation phénotypique des cellules dendritiques : 30.8% et 34.3% pour S. rectivirgula et W. sebi, 62.8% pour E. amstelodami et 10.8% pour M. immunogenum. Des taux élevés d'IL-8 (1490 pg/ml) ont été détectés après exposition à chacun des micro-organismes. Des taux similaires d'IL-10 (490 pg/ml) et d'IL-23 (> 2000 pg/ml) ont été retrouvés après exposition à W. sebi et E. amstelodami alors qu'après exposition à S. rectivirgula les taux d'IL-10 et d'IL-23 retrouvés dans les surnageants étaient plus faibles (80 pg/ml). Seule l'exposition à E. amstelodami a induit la sécrétion d'IL-12 (20 pg/ml). Après MLR, une prolifération des lymphocytes T CD4+ a été observée (>40%). Conclusions Ces premiers essais suggèrent que chaque micro-organisme testé est capable d'activer les cellules dendritiques et d'induire une réponse lymphocytaire de type CD4+. Les variations observées sont probablement liées aux natures différentes des micro-organismes testés (mycobactérie, actinomycète, champignon filamenteux) et donc à la mise en jeu de voies de signalisation différentes. Mots clés: infection-inflammation
Possible Quaternary growth of a hidden anticline at the front of the Jura fold-and-thrust belt: geomorphological constraints from the Forêt de Chaux area, France
18 octobre 2011
This study presents new constraints for Plio-Quaternary (post-2.4 Ma to present-day) anticline growth along the frontal zone of the Jura fold-and-thrust belt, in the Forêt de Chaux area, located 30 km SW of Besançon. The Forêt de Chaux area consists of a N080°E-elongated depression bordered by the Doubs and Loue rivers to the north and south respectively, and filled with Sundgau-type Pliocene alluvial deposits. The upper surface of the Pliocene deposits between the Loue and Doubs rivers is marked by a N065°E-trending ridge crossing the depression in a median position. A differential uplift along this ridge, post-dating the deposition of the gravels (2.4 Ma), is suggested by several geomorphological observations such as the opposite river migration on each side of the ridge as well as variations of drainage geometry and incision intensity. Geological and geophysical subsurface data indicate that the ridge roughly coincides with the axis of an anticline hidden beneath the Pliocene deposits. The observed uplift is presumably related to a post-2.4 Ma anticline growth. The fact that the azimuth of the hidden anticline axis is parallel to the strike of deep-seated Late Paleozoic basement faults and not to the local strike of the thin-skinned Jura structures indicates that the inferred post-Pliocene deformation could possibly be an expression of a recent thick-skinned deformation of the basement of the northern Alpine foreland. The focal depth (15 km) of the February 24th, 2004, Besançon earthquake supports the hypothesis of a basement fault reactivation.
Un nouveau témoignage d'occupation précoce à Augustodunum
17 octobre 2011
La fouille en 2004 d'une nécropole dans le suburbium d'Autun a fourni la rare occasion d'évoquer les prémices de la ville antique à travers la découverte d'un ensemble de tombes augusto- tibériennes. Augustodunum, qui succéda à Bibracte au titre de capitale du peuple éduen, a été créée ex nihilo dans le cadre de la réforme administra- tive des provinces des trois Gaules décidée par l'empereur Auguste, aux alentours de 15 av. J.-C. Les recherches menées sur le mont Beuvray depuis 1985, montrent un abandon progressif de l'oppi- dum, qui s'effectue à partir des dernières années du Ier s. av. J.-C., et révèlent la survivance de grandes demeures mais aussi de certains lieux de culte au- delà de la fondation d'Augustodunum. En parallèle, les investigations réalisées à Autun,bien qu'intenses depuis maintenant une trentaine d'années, ont tou- jours peinéà mettre en évidence des marqueurs augustéens (Rebourg 1991, p. 105). Après avoir dressé un rapide état des connaissances acquises ces dernières années, nous verrons en quoi les tombes mises au jour à Pont-l'Évêque apportent de nouveaux éléments de réflexion concernant les modalités, encore bien mal connues, du transfert de population entre Bibracte et Augustodunum, et la dynamique d'occupation de la nouvelle ville aux premiers temps de son existence.
L'époque gallo-romaine des plaines de Saône aux plateaux jurassiens
14 octobre 2011
Synthèse des données polliniques couvrant l'époque gallo-romaine des des plaines de Saône aux plateaux jurassiens
Contrasting rainfall patterns over North America during the Holocene and Last Interglacial as recorded by sediments of the northern Gulf of Mexico
6 octobre 2011
The comparison of geochemical and mineralogical characteristics of terrigenous sediments deposited in the northern Gulf of Mexico (GoM) during the Holocene and Last Interglacial (LIG) is used to document the impact of slight differences in insolation and ice-sheet retreat rates on moisture transfer and precipitation patterns over central North America. The records indicate distinct sedimentological signatures over the two time periods, which likely reflect a modification of the main detrital provenance during the LIG compared to the Holocene. Here we postulate that the observed differences in the terrigenous supply during the LIG relative to the Holocene reflect a northeast migration of the main precipitation belt over the Mississippi River watershed likely in response to deglaciation of the Laurentide Ice Sheet prior to the peak in boreal summer insolation and the overall greater increase in boreal summer insolation relative to the Holocene. These combined effects allowed more northward migration of the Jet Stream, Atlantic Warm Pool and Intertropical Convergence Zone than during the Holocene, which may have also forced the Bermuda High farther to the northeast of its present position, thereby pumping more moisture from the GoM and the Caribbean region into both the Upper Mississippi River and northeast Great Lakes area. Citation: Montero-Serrano, J.-C., et al. (2011), Contrasting rainfall patterns over North America during the Holocene and Last Interglacial as recorded by sediments of the northern Gulf of Mexico
Paleoproterozoic tectonic evolution of the Trans-North China Orogen: toward a comprehensive model.
30 septembre 2011
In this contribution we present a reconstruction of the overall lithotectonic architecture, from inner zones to external ones, of the Paleoproterozoic Trans North China Orogen, within the North China Craton. Moreover, forward thermobarometrical modeling on a kyanite-bearing gneiss yields a reliable prograde P-T-t-D path. In addition, 40Ar/39Ar dating on rocks from distinct litho-tectonic units helps us to distinguish several tectono-metamorphic events during the orogenic development. Considering these results, we propose a geodynamic model involving three cratonic blocks, namely the Western, Fuping and Eastern Blocks, separated by two oceans, the Lüliang and Taihang Oceans. The opening of oceanic basins occurred around 2.2-2.3 Ga. After the westward subductions of oceanic lithosphere, the Trans-North-China Orogen was built up through a polyphase tectonic evolution within the period 1900-1800 Ma. The first event (D1) corresponded to the emplacement of lower and upper nappes herein called the Orthogneiss-and-Volcanites Unit (OVU) and the Low-Grade-and-Mafic Unit (LGMU), respectively. The syn-metamorphic D1 deformation (1880 ± 10 Ma) is characterized by a NW-SE stretching and mineral lineation with a top-to-the SE sense of shear. During ongoing compression of the thickening orogenic crust, a second deformation event D2 (1850 ± 10 Ma) was responsible for (1) syn-anatectic lateral flow and exhumation of the orogenic root and (2) folding of the middle and upper parts of the orogenic wedge that consequently acquired a fan-type geometry. The late D3 (1830 ± 10 Ma) and D4 (1810 ± 10 Ma) events are related to late-orogenic normal and strike-slip shearing, respectively. In our present state of knowledge, the Paleoproterozoic Trans-North China Orogen might be regarded as the assemblage of two continent-continent collisional belts, both of which are characterized by nappe stacking accommodated by top-to-the E/SE ductile shearing. Continental subduction, crustal thickening, partial melting of overthickened crust, exhumation of HP rocks and deposition of syn-orogenic detrital basins are typical features of modern collisional-type orogens.
Prone position and recruitment manoeuvre: the combined effect improves oxygenation.
28 septembre 2011
INTRODUCTION: Among the various methods for improving oxygenation while decreasing the risk of ventilation-induced lung injury in patients with acute respiratory distress syndrome (ARDS), a ventilation strategy combining prone position (PP) and recruitment manoeuvres (RMs) can be practiced. We studied the effects on oxygenation of both RM and PP applied in early ARDS patients. METHODS: We conducted a prospective study. Sixteen consecutive patients with early ARDS fulfilling our criteria (ratio of arterial oxygen partial pressure to fraction of inspired oxygen (PaO2/FiO2) 98.3 ± 28 mmHg; positive end expiratory pressure, 10.7 ± 2.8 cmH2O) were analysed. Each patient was ventilated in both the supine position (SP) and the PP (six hours in each position). A 45 cmH2O extended sigh in pressure control mode was performed at the beginning of SP (RM1), one hour after turning to the PP (RM2) and at the end of the six-hour PP period (RM3). RESULTS: The mean arterial oxygen partial pressure (PaO2) changes after RM1, RM2 and RM3 were 9.6%, 15% and 19%, respectively. The PaO2 improvement after a single RM was significant after RM3 only (P < 0.05). Improvements in PaO2 level and PaO2/FiO2 ratio were transient in SP but durable during PP. PaO2/FiO2 ratio peaked at 218 mmHg after RM3. PaO2/FiO2 changes were significant only after RM3 and in the pulmonary ARDS group (P = 0.008). This global strategy had a benefit with regard to oxygenation: PaO2/FiO2 ratio increased from 98.3 mmHg to 165.6 mmHg 13 hours later at the end of the study (P < 0.05). Plateau airway pressures decreased after each RM and over the entire PP period and significantly after RM3 (P = 0.02). Some reversible side effects such as significant blood arterial pressure variations were found when extended sighs were performed. CONCLUSIONS: In our study, interventions such as a 45 cmH2O extended sigh during PP resulted in marked oxygenation improvement. Combined RM and PP led to the highest increase in PaO2/FiO2 ratio without major clinical side effects.
Ribosomal and mitochondrial DNA target for real-time PCR diagnosis of invasive aspergillosis.
28 septembre 2011
The aim of the present study was to assess the diagnostic efficacy of a combination of two quantitative Aspergillus PCR assays, targeting a mitochondrial and a ribosomal target, in patients with risk factors for invasive aspergillosis (IA) and positive galactomannan (GM) antigen. Forty-four patients with hematological malignancies and risk factors for IA according to revised European Organization for Research on Treatment of Cancer and the Mycoses Study Group criteria (EORTC/MSG) criteria and presenting at least two sequential GM-positive sera were included in the study. Mitochondrial PCR was carried out prospectively on all GM-positive serum samples. Ribosomal PCR was carried out retrospectively on frozen stored sera. The sensitivities of mitochondrial and ribosomal PCRs were 58% and 50%, respectively. The diagnostic test performance was improved by using a combination of both PCR assays and by considering a patient PCR positive when at least two positive results were obtained. The sensitivity, specificity, and positive and negative likelihood ratios were 65%, 94%, and 11.8 and 0.37, respectively. A significant association between fatal outcome at 90 days and positive results of ribosomal PCR assays was observed (adjusted hazard ratio = 8.2; 95% confidence interval [CI] = 1.0 to 65.8; P = 0.048). Our results showed that the combination of two PCR assays targeting mitochondrial and ribosomal Aspergillus DNA improves the sensitivity of PCR in the diagnosis of IA in hematological patients with risk factors and positive GM results. This study also confirms that a positive PCR result is associated with a poor prognosis in these patients and should lead to specific antifungal therapy being introduced immediately.
Longitudinal analysis and genotyping of infant dominant bifidobacterial populations.
28 septembre 2011
Bifidobacterial population dynamics were investigated by the longitudinal analysis of the dominant population isolated from the feces of young infants. After molecular identification and fingerprinting comparison, clone identity of the consecutive strains belonging to the same species for one individual was performed by pulsed-field gel electrophoresis. The results, obtained from 15 individuals sampled four times over a five-week period suggested a turnover of the dominant bifidobacteria in the population not only at the species but also at its species representative levels. This study provides new insights of the in vivo dynamics of commensal bifidobacteria. It highlights the need to take into consideration the fluctuation of bifidobacterial populations that may occur in one individual in order to investigate reliably the impact of dietary components, such as probiotics or prebiotics, on the intestinal ecosystem.
Relationship between prevalence of device-associated infections and alcohol-based hand-rub consumption: a multi-level approach.
28 septembre 2011
Using a multi-level logistic regression model, we determined whether there was any relationship between alcohol-based hand-rub consumption and prevalence of device-associated infections (DAIs) in French healthcare facilities (HCFs). Two national databases were used: the 2006 French prevalence survey of nosocomial infections, and the 2006 French infection control indicator database which includes alcohol-based hand-rub consumption as an indicator (ICSHA: indicateur de consommation de solution hydro-alcoolique). Only patients with at least one medical device (urinary catheter, vascular catheter or tracheal tube) who were present in an HCF for at least two days were included in the analysis. A multi-level statistical analysis was performed to assess the joint effect of patient-level and hospital-level variables. In all, 814 HCFs, each with a minimum of 15 study patients, were included, giving a total of 53,459 patients. The overall prevalence of DAI was 6.7% (95% confidence interval: 6.4-6.9). The median value of ICSHA was 37.2%. There was no association between DAI prevalence and ICSHA, but all patient-level variables were associated with DAI prevalence. Patient-level variables explain 25% of the hospital-level variation in DAI prevalence, although 60% of this variation remains unexplained when both patient and hospital variables are included in the model. To further assess any association between DAI prevalence and hand hygiene, additional studies on hand hygiene practices specifically associated with invasive medical device manipulation are required.
Bacterial contamination of organ graft preservation solution and infection after transplantation.
28 septembre 2011
Infectious complications represent a major cause of morbidity and mortality in patients with organ transplantation. Contamination of preservation solution (PS) can lead to life-threatening complications in the recipients. For a 3-year period, we investigated the bacterial contamination of both PSs and graft fragments, recipient infections, and explored the link between them. In total 137 organs were transplanted, and 131 organ and perfusate cultures out of 426 tested (30.8%) gave a positive bacterial culture, mainly with coagulase-negative staphylococci. Overall, 80 recipients out of 137 (58.4%) had at least 1 infection during the 4-month post-graft surveillance period. Twelve recipients had an infection with the same bacterial species that was recovered in the corresponding graft. However, based on pulsed-field gel electrophoresis typing results, only 1 case was very likely cross-transmitted via the transplantation.
Strain-tailored double-disk synergy test detects extended-spectrum oxacillinases in Pseudomonas aeruginosa.
28 septembre 2011
The prevalence of class D extended-spectrum oxacillinases (ES-OXAs) in ceftazidime-resistant strains of Pseudomonas aeruginosa is often underestimated by double-disk synergy tests (DDST) using clavulanate. A DDST with a customized distance between a disk of ceftazidime or cefepime and inhibitors (clavulanate and imipenem) detected 14 out of 15 different ES-OXAs.
Impact of barrier precautions and antibiotic consumption on the incidence rate of acquired cases of infection or colonization with Acinetobacter baumannii: A 10-year multi-department study.
28 septembre 2011
Following a previous investigation, this ecological study assessed the impact of barrier precautions and various factors on the annual incidence rate of acquired Acinetobacter baumannii cases in each of the 32 departments of the University Hospital of Besançon from 2000 to 2009. Ultimately, our study confirms the effectiveness of barrier precautions in addition to standard precautions for controlling A baumannii within our hospital departments. In comparison with the previous research, it emphasizes the significant role of fluoroquinolones in the emergence and the spread of this microorganism.
Most multidrug-resistant Pseudomonas aeruginosa isolates from hospitals in eastern France belong to a few clonal types.
28 septembre 2011
This study aimed to determine the genetic diversity of clinical multidrug-resistant Pseudomonas aeruginosa. We used pulsed-field gel electrophoresis and multilocus sequence typing to analyze 187 strains isolated in different French hospitals. To illustrate the diversity of resistance mechanisms to antibiotics in a given clone, we identified β-lactamases with an extended spectrum by using phenotypic and genotypic methods. Typing results showed that the majority of our multidrug-resistant isolates belong to a few clonal types (ST235, ST111, and ST175) that are already spreading worldwide. These successful international clones sporadically produced extended-spectrum β-lactamase-encoding genes but mostly became extensively resistant to β-lactams after derepression of intrinsic resistance mechanisms (i.e., AmpC cephalosporinase). Our results indicate that cross-transmission plays a major role in the spread of multidrug-resistant P. aeruginosa in hospital settings.
Multilevel modelling of the prevalence of hospitalized patients infected with Pseudomonas aeruginosa.
27 septembre 2011
Pseudomonas aeruginosa is one of the leading nosocomial pathogens. The question of the respective contribution of endogenous and exogenous sources remains controversial. In this study, we shed new light on this issue by means of a multilevel logistic regression analysis which allowed a simultaneous investigation of factors associated with prevalence of patients infected with P. aeruginosa at two levels: patient and healthcare facility (HCF) in the eastern regions of France. A total of 25 533 in-patients from 51 HCFs were included in the analysis. The overall prevalence was 0*37% (range 0-1*65%). Multilevel modelling estimated that <14% of total variability of the outcome variable was explained by differences between HCFs and that after adjusting for patient-level variables, which explained 52% of HCF-level variance, the latter became non-significantly different from zero. A compositional effect (patient factors), rather than a contextual effect (ecological factors), explains heterogeneity of the prevalence of patients infected with P. aeruginosa in the eastern HCFs of France.
Climatic modifiers of the response to nitrogen deposition in peat-forming Sphagnum mosses: a meta-analysis
26 septembre 2011
* Peatlands in the northern hemisphere have accumulated more atmospheric carbon (C) during the Holocene than any other terrestrial ecosystem, making peatlands long-term C sinks of global importance. Projected increases in nitrogen (N) deposition and temperature make future accumulation rates uncertain. * Here, we assessed the impact of N deposition on peatland C sequestration potential by investigating the effects of experimental N addition on Sphagnum moss. We employed meta-regressions to the results of 107 field experiments, accounting for sampling dependence in the data. * We found that high N loading (comprising N application rate, experiment duration, background N deposition) depressed Sphagnum production relative to untreated controls. The interactive effects of presence of competitive vascular plants and high tissue N concentrations indicated intensified biotic interactions and altered nutrient stochiometry as mechanisms underlying the detrimental N effects. Importantly, a higher summer temperature (mean for July) and increased annual precipitation intensified the negative effects of N. The temperature effect was comparable to an experimental application of almost 4 g N m)2 yr)1 for each 1°C increase. * Our results indicate that current rates of N deposition in a warmer environment will strongly inhibit C sequestration by Sphagnum-dominated vegetation.
Growth and metal accumulation in Porcellio scaber exposed to poplar litter from Cd-, Pb-, and Zn-contaminated sites.
26 septembre 2011
This study aimed at determining, in the laboratory, the effects of poplar litter collected in woody habitats contaminated by heavy metals on growth and metal accumulation in the terrestrial isopod Porcellio scaber. Cd, Pb, and Zn pseudototal and CaCl(2)-extractable concentrations in litter types were determined using AAS. Juveniles were fed ad libitum, individually, for 28 days with four litter types presenting an increasing gradient of metal contamination. Individuals were weighed every week and metal body burdens were determined at the end of the experiment. From the first week until the end of the experiment, a decrease in P. scaber growth related to the increase of metal concentration in litter types was recorded. Significant correlations were observed between metal body burdens and metal concentrations in litter types. However, Cd accumulation in woodlice appeared to be related to the Cd/Zn concentration ratio in litter types. All these results showed the potential of weight gain in P. scaber as a suitable indicator for litter quality assessment with ecological relevance.
Massively multiplayer online role-playing games: comparing characteristics of addict vs non-addict online recruited gamers in a French adult population.
23 septembre 2011
UNLABELLED: ABSTRACT: BACKGROUND: Massively Multiplayer Online Role-Playing Games (MMORPGs) are a very popular and enjoyable leisure activity, and there is a lack of international validated instruments to assess excessive gaming. With the growing number of gamers worldwide, adverse effects (isolation, hospitalizations, excessive use, etc.) are observed in a minority of gamers, which is a concern for society and for the scientific community. In the present study, we focused on screening gamers at potential risk of MMORPG addiction. METHODS: In this exploratory study, we focused on characteristics, online habits and problematic overuse in adult MMORPG gamers. In addition to socio-demographical data and gamer behavioral patterns, 3 different instruments for screening addiction were used in French MMORPG gamers recruited online over 10 consecutive months: the substance dependence criteria for the Diagnostic and Statistical Manual of Mental Disorder, fourth revised edition (DSM-IV-TR) that has been adapted for MMORPG (DAS), the qualitative Goldberg Internet Addiction Disorder scale (GIAD) and the quantitative Orman Internet Stress Scale (ISS). For all scales, a score above a specific threshold defined positivity. RESULTS: The 448 participating adult gamers were mainly young adult university graduates living alone in urban areas. Participants showed high rates of both Internet addiction (44.2% for GIAD, 32.6% for ISS) and DAS positivity (27.5%). Compared to the DAS negative group, DAS positive gamers reported significantly higher rates of tolerance phenomenon (increased amount of time in online gaming to obtain the desired effect) and declared significantly more social, financial (OR: 4.85), marital (OR: 4.61), family (OR: 4.69) and/or professional difficulties (OR: 4.42) since they started online gaming. Furthermore, these gamers self-reported significantly higher rates (3 times more) of irritability, daytime sleepiness, sleep deprivation due to play, low mood and emotional changes since online gaming onset. CONCLUSIONS: The DAS appeared to be a good first-line instrument to screen MMORPG addiction in online gamers. This study found high MMORPG addiction rates, and self-reported adverse symptoms in important aspects of life, including mood and sleep. This confirms the need to set up relevant prevention programs against online game overuse.
Rapid Discrimination between Candida glabrata, Candida nivariensis, and Candida bracarensis by Use of a Singleplex PCR
20 septembre 2011
We report here a PCR-based assay using a single primer pair targeting the RPL31 gene that allows discrimination between Candida glabrata, Candida bracarensis, and Candida nivariensis according to the size of the generated amplicon.
Typologie et fonctionnement des manchons des moulins rotatifs manuels durant le deuxième âge du fer et le Haut-Empire
19 septembre 2011
Snails as indicators of pesticide drift, deposit, transfer and effects in the vineyard
15 septembre 2011
This paper presents a field-study of real pesticide application conditions in a vineyard. The objective was to measure the exposure, the transfer and the effects of pesticides on a non-target soil invertebrate, the land snail Helix aspersa. There was no drift of the herbicides (glyphosate and glufosinate) whereas the fungicides (cymoxanil, folpet, tebuconazole and pyraclostrobin) were detected up to 20 m from the treated area. For folpet and particularly tebuconazole, spray deposits on soil (corresponding to losses for the intended target i.e. the vine leaves) were high (41.1% and 88.8% loss of applied dose, respectively). For herbicides, the target was the soil and losses (percentage of compounds which did not reach the soil) were of 22% for glufosinate and 52% for glyphosate. In the study plot, glyphosate was transferred to and accumulated in snail tissues (4 mg kg−1 dry weight, dw), as was its metabolite AMPA (8 mg kg−1 dw) which could be in relation with the reduced growth observed in snails. No effects on snail survival or growth were found after exposure to the other organic compounds or to copper and sulphur-fungicides, although transfer of tebuconazole, pyraclostrobin and copper occurred. This study brings original field data on the fate of pesticides in a vineyard agro-ecosystem under real conditions of application and shows that transfer and effects of pesticides to a non-target organism occurred.
Wild brown trout affected by historical mining in the Cévennes national park, France.
9 septembre 2011
In the protected area of the Cévennes National Park (Southern France), 114 wild brown trout (Salmo trutta fario) were captured at six locations affected to different extents by historical mining and metallurgy dating from the Iron Age to Modern Times. Cadmium and lead in trout livers and muscles reflect high sediment contamination, although an age-related effect was also detected for hepatic metal concentrations. Lead isotope signatures confirm exposure to drainage from mining and metallurgical waste. Developmental instability, assessed by fluctuating asymmetry, is significantly correlated with cadmium and lead concentrations in trout tissues, suggesting that local contamination may have affected fish development. Nowadays, the area is among the least industrialized in France. However, our results show that 60% of the specimens at one site exceed EU maximum allowed cadmium or lead concentration in foodstuffs. The mining heritage should not be neglected when establishing strategies for long-term environmental management.
Using the concept of spatial contexts for the prediction of archaeological rural settlement
31 août 2011
Polyphase seismic faulting in the Ivrea zone (Italian Alps) revealed by Ar-40/Ar-39 dating of pseudotachylytes
29 août 2011
P>Most fault-related pseudotachylytes in the Val Sesia area, Ivrea zone, NW Italian Alps, occur in two areas: near the Canavese Line in the Kinzigite Formation paragneisses and in an elongate belt in the Mafic Complex gabbros away from the Canavese Line. Ar-40/Ar-39 dating indicates that pseudotachylytes from the Kinzigite Formation were formed in the late Eocene, likely during the early stages of the collision between the NW corner of the Adriatic indenter and the European margin. Pseudotachylytes from the Mafic Complex were formed under a transpressive strain regime, as suggested by kinematic indicators, and yield Early Cretaceous (Albian) Ar-40/Ar-39 ages. Their formation is possibly related to shortening during the inception of the tectonic inversion of the Adriatic passive margin.
Role of dog behaviour and environmental fecal contamination in transmission of Echinococcus multilocularis in Tibetan communities.
26 août 2011
SUMMARYOn the Eastern Tibetan Plateau region (Sichuan province, China) dogs are regarded as important definitive hosts of Echinococcus multilocularis. We studied dog spatial behaviour in 4 Tibetan villages in order to determine the role of dogs in environmental contamination and their potential interactions with small mammal intermediate hosts. We identified definitive host species and Echinococcus spp. infection status of feces collected in the field by PCR methods and analysed the spatial distribution of canid feces. Nocturnal space utilization of GPS collared dogs in and around villages was also undertaken. E. multilocularis DNA was amplified in 23% of dog feces (n=142) and in 15% of fox feces (n=13) but this difference was not significant. However, dog feces were more frequently observed (78% of collected feces) than fox feces and are therefore assumed to largely contribute to human environment contamination. Feces were mainly distributed around houses of dog owners (0-200 m) where collared dogs spent the majority of their time. Inside villages, the contamination was aggregated in some micro-foci where groups of dogs defecated preferentially. Finally, small mammal densities increased from the dog core areas to grasslands at the periphery of villages occasionally used by dogs; male dogs moving significantly farther than females. This study constitutes a first attempt to quantify in a spatially explicit way the role of dogs in E. multilocularis peri-domestic cycles and to identify behavioural parameters required to model E. multilocularis transmission in this region.
Reinstatement of the endemic New Caledonian genus Thiollierea Montrouz. (Rubiaceae) necessitated by the polyphyly of Bikkia Reinw. as currently circumscribed
26 août 2011
The genus Bikkia Reinw. as currently circumscribed comprises 20 species distributed throughout the western Pacifi c Ocean, with a center of diversity in New Caledonia (11 species, all but one endemic). Two recent phylogenetic studies based respectively on molecular and morphological data have shown that Bikkia s.l. is polyphyletic, comprising two lineages: coastal Bikkia from the western Pacifi c (including the type species of the genus, B. tetrandra (L.f.) A.Rich.) and endemic New Caledonian Bikkia, a situation that necessitates the resurrection of the generic name Th iollierea Montrouz., the oldest available for the second of these groups. An emended description is provided for Thiollierea as well as a summary of the features that distinguish it from Bikkia s.s., and seven new combinations are proposed (T. kaalaensis (N.Hallé& Jérémie) Barrabé& Mouly, T. lenormandii (N.Hallé& Jérémie) Barrabé& Mouly, T. neriifolia (Brongn.) Barrabé& Mouly, T. pachyphylla (Guillaumin) Barrabé& Mouly, T. parviflora (Schltr. & K.Krause) Barrabé& Mouly, T. retusifl ora (Brongn.) Barrabé& Mouly and T. tubiflora (Brongn.) Barrabé& Mouly).
Deux espèces nouvelles de Thiollierea (Rubiaceae) restreintes aux sols hypermagnésiens du massif du Boulinda (Nouvelle-Calédonie)
26 août 2011
Deux espèces nouvelles de Thiollierea (Rubiaceae) endémiques de Nouvelle-Calédonie sont décrites et illustrées. Une clé de détermination des espèces du genre Thiollierea est donnée. Thiollierea rigaultii sp. nov. et T. dagostinii sp. nov. appartiennent au groupe des espèces à fleurs blanches et violacées. Thiollierea rigaultii sp. nov. possède des caractères uniques pour ce groupe : inflorescences unifl ores, face interne du calice totalement recouverte par des cérocystes, corolle coriace et de grande taille. Thiollierea dagostinii sp. nov. est caractérisée par une combinaison inédite de caractères : face interne des stipules entièrement recouverte par des cérocystes, hypanthe subailé, tube du calice entier sans division secondaire, pilosité du fi let hirsute et lâche, à disposition cylindrique. Les deux espèces sont endémiques du massif ultramafique du Boulinda, situé sur la côte nord-ouest de la Grande Terre, et plus précisément, pour chacune, d'une petite région paraforestière sur sols hypermagnésiens conférant à la flore locale des taux élevés de microendémisme. L'état actuel des populations des deux espèces et l'examen des menaces qui pèsent sur elles permettent de proposer un statut UICN correspondant à la catégorie " en danger critique d'extinction " (CR).
Molecular phylogeny and taxonomic revision of the Philippine endemic Villaria Rolfe (Rubiaceae)
26 août 2011
The little known Rubiaceae genus Villaria is endemic mostly to the coastal forests of the Philippines. Traditionally, it has been placed in the tribe Gardenieae. Later it was transferred to Octotropideae sensu Robbrecht and Puff. Villaria was placed among the ''primitive'' genera of the tribe, which are essentially characterized by large fruits, horizontal ovules and numerous seeds. Parsimony and Bayesian analyses of the combined plastid (rps16 and trnT-F) dataset strongly support the inclusion of Villaria in Octotropideae as well as monophyly of the genus. However, our molecular results do not conform to the current informal groups of the tribe delimited by fruit size, ovule position, number of seeds and exotesta thickenings. Instead, a close relationship between Villaria and two ''central genera'' (Hypobathrum and Pouchetia) is revealed for the first time. This clade is sister to a group comprising ''primitive'' (Fernelia), ''advanced'' (Kraussia and Polysphaeria) and ''central'' (Feretia) representatives. In addition, our combined tree strongly supports a sister taxa relationship between Canephora and Paragenipa. Villaria is characterized by unilocular ovaries, parietal placentation and strictly horizontal ovules. These features are unique within the Octotropideae. We recognize a total of five Villaria species, one new species (V. leytensis) is described here, and two species (V. philippinensis and V. rolfei) are transferred into synonymy with V. odorata. Each species is fully described, and a key to the species, a distribution map and illustrations are provided.
The LIEPPEC Project: using lidar for the study of long term landscape change
25 août 2011
The LIEPPEC (Lidar pour l'étude des paysages passés et contemporains) project is designed to investigate long term change in the landscapes around the urban centre of Besançon and the villages of Mandeure and Mathay, in the Franche-Comté region of France. The project uses microtopographic data produced through lidar surveys as a framework, focusing attention on the process of landscape formation and development.
Spectrocolorimetric interpretation of sedimentary dynamics: The new "Q7/4 diagram"
19 août 2011
Colour is a fundamental property of sediment and is often used for lithographic description to determine sedimentological structures, facies etc. However, the sedimentary information contained in this parameter is difficult to extract because it is difficult to quantify. Colour can be quantified by spectrocolorimetry which provides very high resolution data quickly and non-destructively. When adapted to sedimentology, spectrocolorimeters prove to be powerful tools due to their low purchase and maintenance costs, and some are portable and easily used in-the-field. Several methods have been used to extract sedimentological data from colorimetric spectra (first derivatives, factorial analysis, etc.). In the present study, we first provide a review of the sedimentological application of spectrophotometers and, after having described these methods, their advantages and disadvantages, we then describe a new tool called the Q7/4 diagram (abscissa L*; Ordinates 700/400 ratio). This new technique permits sedimentological units to be defined, allows the identification of different sediment components and provides 5 distinct poles: Clayey deposits, organic rich deposits (chlorophyll a and by products), altered organic matter deposits, iron rich deposits, carbonated deposits. Coupled with the analysis of first derivative spectra, it is possible to distinguish different pigments linked to the degradation and/or nature of the organic material (Chlorophyll a, melanoidin, etc.), the state of iron oxidation (for example, hematite and goethite-like signatures) and the nature of clays. The Q7/4 diagram permits rapid acquisition of high resolution data on changes of sediment dynamics in geosystems that have been subjected to highly varied climatic/environmental conditions. The instrument is non destructive, easy to use and maintain, portable for use in the field, fast to implement, is capable of high resolution, and has a vast range of possible applications. Spectrocolorimetry appears to provide many advantages and could become an essential and robust tool for preliminary sedimentological studies.
Effects of short-term ecosystem experimental warming on water-extractable organic matter in an ombrotrophic Sphagnum peatland (Le Forbonnet, France)
19 août 2011
In a future warmer world, peatlands may change from a carbon sink function to a carbon source function. This study tracks changes in water-extractable organic matter (WEOM) after one year of in situ experimental warming using open top chambers (OTCs). WEOM was studied in the upper peat layers (0-10 cm) through analysis of water-extractable organic carbon (WEOC), stable C isotopic composition (δ13C), specific UV absorbance at 280 nm and sugar composition of cores taken from an open bog (DRY sites) and a transitional poor fen (WET sites). At the DRY sites, the impact of OTCs was weak with respect to WEOM parameters, whereas at the WET sites, the air warming treatment led to a decrease in peat water content, suggesting that the supply of heat by OTCs was used mainly for evapotranspiration. OTCs at the WET sites also induced a relative enrichment at the surface (0 to 5 cm depth) of aliphatic and/or aromatic compounds with concomitant decrease in WEOC, as a result of decomposition. On the contrary, WEOC and sugar content increased in the deeper peat layer (7.5-10 cm depth) probably as a result of increased leaching of phenolic compounds by roots, which then inhibits microbial activity. The different response to experimental warming at DRY and WET sites suggests that the spatial variability of moisture in is critical for understanding of the impact of global warming on the fate of OM and the carbon cycle in peatlands.
HP-UHP metamorphism as an indicator of slab dip variations in the Alpine arc
27 juillet 2011
HP/UHP and LT metamorphic units that commonly occur in the inner parts of mountain belts result from the subduction of continental and oceanic material, most often exhumed prior to continental collision. The prograde pressure-temperature history of HP-UHP rocks strongly depends on the convergence rate and on the subduction zone geometry. The maximum pressure recorded provides a proxy for the depth of shearing off and stacking of HP metamorphic nappes. A 2-D thermal model of continental subduction at lithospheric scale is used to compute the length and pressure peak of detached HP metamorphic units as a function of the slab dip angle and the convergence rate. Model results are applied to the metamorphic nappe pile of the inner Alps. A mean convergence rate of 1 cm/year during the subduction of the Briançonnais terrane is indicated by the paleogeographic reconstructions between 46 and 38 Ma. On this basis, the available petrological data and lengths of metamorphic units are used to compute the variations of the slab dip angle. The slab dip angle is shown to increase, from the northeast to the southwest, along the Alpine arc with estimated values of 20° for Suretta, 30-45° for Monte Rosa and Gran Paradiso, and 60° for Dora Maira. From Eocene to Oligocene times, the increase in slab dip angle is controlled by changes of buoyancy, due to the spatial configuration of the Valaisan trough and the incoming of crustal material within the subduction zone
Landscape, water vole and common buzzard populations: do they correlate?
24 juillet 2011
Since the 1970s, changes in agricultural practices in French mountain areas have produced large homogeneous grassland ecosystems. This has led to population outbreaks of a grassland rodent, the fossorial water vole (Arvicola terrestris) which causes severe damages on harvests and economic losses. Predators are believed to be an important regulating factor of the water vole population dynamics. During 8 years, A. terrestris populations and their diurnal predators were monitored on 5 study sites in Auvergne. Here we focus on the common buzzard (Buteo buteo), the most abundant predator locally, and we examine if this species responds to vole population and landscape feature variations. Analyses were performed using generalized linear mixed effect models. Results showed positive relationships between A. terrestris and B. buteo densities in autumn without time-lag and in spring with a time-lag of one year. Furthermore, large abundances of common buzzard were associated with an important number of patches of forest and small size plots of grassland. In the literature and compared to open grassland, those areas have lower population densities and smaller fluctuations of A. terrestris in average. However, although our results were suggestive, here we failed to detect such a difference statistically, probably due to the relatively small sample size used in our study. This study confirms that the common buzzard favours fine grain landscape mosaic of wood and grasslands and that current or past abundance of water voles modulate the common buzzard foraging strategy. This has important consequences in term of pest control and biological conservation.
Habitat and connectivity of the black snub-nosed monkey (Rhinopithecus bieti) populations in Yunnan: a climate change scenario
24 juillet 2011
During the past 50 years the climate zonation of Yunnan Province, China, has shown a shift towards higher altitude and higher latitudes (Chen et al.2008). In the same time, human population increase led to the encroachment of intensive agriculture and cities on more natural areas. The black snub-nosed monkey (Rhinopithecus bieti) is an endangered species of China endemic to Yunnan. It has 13 discrete population patches, totaling about 1,500 individuals (Long et al.1994 and 1996). They are distributed across a narrow mountainous region stretching between the Jinsha and Lancang rivers, from Mangkang in Tibet (29°20'N, 98°38'E) to Yunlong in Yunnan (25°53'N, 99°22'E). Based on satellite imagery and field surveys the present study analyzes the spatial distribution of the optimal habitats for this species and their connectivity. Results are compared to the population genetic characteristics (Liu et al. 2007) of the population patches. They indicate that some populations are isolated by highways and road networks, dense arable land, and residential areas. Climate and socio-economics scenarios were used to model land cover changes until 2050, predicting that cultivated land will increase of about 66% until 2050. Suitable habitats for the Snub Nosed Monkey will be reduced by 15%. Patch connectivity is currently under study using a least cost distance approach.
Assessing habitat connectivity of the lesser horseshoe bat using graph theory to explain its distribution
24 juillet 2011
The lesser horseshoe bat, Rhinolophus hipposideros was formerly widespread and quite common in north-western Europe, but has undergone a dramatic decline from the 1960s. The main hypothesis for this decline is a change of habitat quality. Recent works have stressed the importance of good connection between roosts and foraging areas by tree lines and well-structured hedgerows. Thus, landscape connectivity is assumed to be a key-factor for population sustainability. The present study is based on a case study in Franche-Comté (France). Its purpose is to model the distribution of the lesser horseshoe bat and to characterize the functional connectivity of its habitat. Graph theory is used efficiently in landscape ecology as a framework to model landscape connectivity (Galpern et al., 2011). In such approach, habitat patches defined as optimal for the focal species are considered as the nodes of a network. Connections between nodes are set up from ecological assumptions concerning the movements of the species within the landscape. The graph resulting from these connections allows quantifying the connectivity by means of different metrics. In the present case, patches were defined as composite objects requiring both places of potential roosts (i.e. small villages) and wooded environment. Among the different types of graph, we focused on the minimal planar graph, where all pairs of nearby patches are linked by the least-cost distance. This graph allowed computing several patch-based metrics including a parameter of dispersal distance. They were included in a species distribution model as explanatory factors in addition to other potential factors impacting movement and distribution as light pollution.
Landscape effects on small mammal communities and population dynamics
24 juillet 2011
In a fascinating article, Delibes-Mateos et al. (2011) pint point that small mammals such as the European rabbits, the plateau pikas, the prairie dogs have been traditionally perceived as pests and targeted for control on a very large scale despite their importance as key-stone species in their native ecosystem. This is also the case for many species of voles in Eurasia and North America (see e.g. Giraudoux and Raoul 2010). However, although a considerable number of studies have been undertaken at local and other scales to understand the mechanisms of vole population outbreaks and cycles, few of them provide basic concepts and useful elements that can be used by ecosystem managers on the scales requested. Lidicker (1995) and Barret & Peles (1999) wrote the first books providing a landscape ecology perspective to small mammal studies. During the 90s, a number of studies have shown that small mammal population management could be grounded on knowledge on the effect of landscape on population dynamics. Here we present results obtained from the long term and multi-scale study of two grassland species, Microtus arvalis and Arvicola terrestris to illustrate this approach. We describe at which scales landscape variables were found relevant to explain population dynamics and the consequences of the observed population dynamic patterns on the vertebrate community (other small mammal species and predators including species of conservation value). We argue that long term observational studies at various scales are of primary importance to understand the role of small mammals in regional ecosystems and essential to put experimental studies into relevant context. Such knowledge is critical to provide managers with useful concepts for integrated sustainable landscape management, to protect biodiversity and also for pest and disease control.
Evolution of Nurses' Social Representation of hospital Hygiene : from training to practice
19 juillet 2011
Isotopes and groundwater management strategies under semi-arid area : case of the Souss upstream basin (Morocco)
12 juillet 2011
This study concerns the Souss upstream basin. The objective is to investigate the characteristics of surface water and groundwater, to assess the impact of artificial recharge as reinforcement of the natural replenishment and assess the renewal of groundwater under semi-arid area. Two major water types are observed: (i) surface waters and upstream springs (least mineralized) and (ii) all groundwater samples (prevailing calcium and magnesium bicarbonate water type). Water isotopes show a low evaporation of precipitations during infiltration. Impoverishment in heavy isotopes is the characteristic of mountain rainfalls, or of a climate colder and wetter than present. Carbon-14 activities (34-94 pmc) indicate a long residence time. The artificial recharge is low compared to the reservoir volume, due to which the renewal rate is also low. (C) 2011 Elsevier Ltd. All rights reserved.
Holocene fire regime changes from multiple-site sedimentary charcoal analyses in the Lourdes basin (Pyrenees, France)
23 juin 2011
One lake and three peat bogs from the Lourdes glacial basin (France) were used for macrocharcoal analyses and fire frequency reconstruction over the entire Holocene (11700 years). The chronology was based upon thirty-three 14C AMS dates. Comparison of the distribution of both CHarcoal Accumulation Rate (CHAR) and fire return intervals showed that charcoal accumulation significantly differs between the lake and the peat bogs, but that frequency calculation overcomes the disparity between these site types. A composite frequency was built from the four individual records to assess regional versus local variability and fire regime controls by comparisons with regional fire activity, Holocene climatic oscillations and vegetation history. The millennial variability can be depicted as follows: relatively high frequency between 8000 and 5000 cal a BP (up to 5 fires/500 yrs), relatively low frequency between 5000 and 3000 cal a BP (down to 0 fires/500 yrs), and an increase between 3000 and 500 cal a BP (up to 4 fires/500 yrs). From 8000 to 5000 cal a BP, fire frequency displays strong synchrony between sites and appears to be mostly driven by increased summer temperature characterizing the Holocene Thermal Maximum (HTM). On the contrary, during the last 3000 years fire frequency was heterogeneous between sites and most probably human-driven. However, higher frequency at the millennial scale during the mid-Holocene strongly suggests that the perception of human-driven fire regime depends on the strength of natural controls.
Le site du Limon-Raspail à Bédoin dans le Vaucluse et le Néolithique final de moyenne vallée du Rhône
17 juin 2011
Holocene vegetation, landscape, and reconstruction of human activity from Prehistory to Roman times based on new pollen data performed in "the plateau de Millevaches" (Limousin, Massif central, France).
17 juin 2011
New pollen analyses from four peat bogs and fens located on the plateau de Millevaches (Limousin, French Massif Central) are compared with one peat sequence situated at lower altitude in the northern Limousin (Mont d'Ambazac). This study, which is supported by eleven accepted AMS radiocarbon data, was undertaken to consider changes in regional vegetation from the beginning of the Holocene and to provide a first reconstruction of land-use history. A singular vegetation history characterizes the "plateau de Millevaches" from the center of the French Massif Central such as the simultaneous start of Corylus and Quercus dated from ca. 10560-10150 cal. BP (ca. 8550-8200 cal. BC). The composition of the forest cover remained largely unchanged with a large supremacy of Corylus in the regional vegetation until ca. 8050-7650 cal. BP (ca. 6100-5700 cal. BC) when the decline of Corylus was synchronous with the expansion of Quercus. The diversified oak woodlands were rapidly filled by Tilia, and pollen data indicate early Neolithic farming around 6600-6500 cal. BP (ca. 4600-4500 cal. BC). The installation of Fagus, which is dated about 5660-5300 cal. BP (ca. 3700-3400 cal. BC), occurs nearly 700 years later than in neighbouring Auvergne. The first oak and beech forests spread after ca. 4800-4400 cal. BP (ca. 2850-2450 cal. BC), and Fagus constitutes the dominant arboreal taxa in the regional vegetation only since ca. 3900-3550 cal. BP (ca. 1930-1530 cal. BC). While climatic factors may have played a major role in its delayed installation, these new pollen analyses provide the first pollen evidence of an anthropogenic factor particularly for the late Neolithic - early Bronze Age transition when increased human pressure (woodland clearances and presence of agricultural and grazing indicators) is evidenced. Different stages related to human activities are shown for the following periods. According to the pollen data, between ca. 2350-2100 cal. BP (ca. 400-150 cal. BC), the second Iron Age, and more particularly, the 4th-2nd centuries BC, represents an important threshold in the shaping of this medium mountain cultural landscape. Large beech-oak forest clearances are related to an important agropastoral extension which continues to increase during the beginning of the Roman period.
Human exposure to allergenic pollens: A comparison between urban and rural areas.
17 juin 2011
Background: Pollinosis is found more frequently in urban areas than in rural environments. This could be partly related to the different types of pollen exposure in these dissimilar areas. The objective of this study was to compare the distribution of pollen in these environments across an urbanization gradient. Methods: Daily pollen abundances were obtained in France using Hirst-type sensors. Sampling was conducted from January to June in 2003 and 2006 in a rural area, a semi-rural area and in two urban areas, which were characterized by several urbanization criteria. Results: Total allergenic pollen abundance was higher in rural and semi-rural areas than in urban areas irrespective of the sampling year. Multivariate analyses showed that pollen exposures differed according to the type of area and were strongly explained by the urbanization gradient. Grass, ash, birch, alder, hornbeam, hazel and plantain pollen quantities exceeded the allergy threshold more often in rural settings than in urban areas. In urban areas, only plane pollen quantities exceeded the allergy threshold more often than in rural areas. Conclusions: Allergenic pollen exposure is higher in rural areas than in urban areas, and the most abundant pollen in each area did not originated from the same taxa. This result should be taken into account in epidemiological studies comparing allergies in rural and urban areas to adapt the panel of pollen extracts for human environmental exposure. In addition, this study highlights that some ornamental trees produce a large number of allergenic pollens and provide new sources of aeroallergens.
HOLOCENE VEGETATION, LANDSCAPE AND RECONSTRUCTION OF HUMAN ACTIVITY FROM PREHISTORY TO THE ROMAN PERIOD BASED ON NEW POLLEN DATA PERFORMED IN "THE PLATEAU DE MILLEVACHES" (LIMOUSIN, MASSIF CENTRAL, FRANCE)
17 juin 2011
New pollen analyses from four peat bogs and fens located on the plateau de Millevaches (Limousin, French Massif Central) are compared with one peat sequence situated at lower altitude in the northern Limousin (Mont d'Ambazac). This study, which is supported by eleven accepted AMS radiocarbon data, was undertaken to consider changes in regional vegetation from the beginning of the Holocene and to provide a first reconstruction of land-use history. A singular vegetation history characterizes the "plateau de Millevaches" from the center of the French Massif Central such as the simultaneous start of Corylus and Quercus dated from ca. 10560-10150 cal. BP (ca. 8550-8200 cal. BC). The composition of the forest cover remained largely unchanged with a large supremacy of Corylus in the regional vegetation until ca. 8050-7650 cal. BP (ca. 6100-5700 cal. BC) when the decline of Corylus was synchronous with the expansion of Quercus. The diversified oak woodlands were rapidly filled by Tilia, and pollen data indicate early Neolithic farming around 6600-6500 cal. BP (ca. 4600-4500 cal. BC). The installation of Fagus, which is dated about 5660-5300 cal. BP (ca. 3700-3400 cal. BC), occurs nearly 700 years later than in neighbouring Auvergne. The first oak and beech forests spread after ca. 4800-4400 cal. BP (ca. 2850-2450 cal. BC), and Fagus constitutes the dominant arboreal taxa in the regional vegetation only since ca. 3900-3550 cal. BP (ca. 1930-1530 cal. BC). While climatic factors may have played a major role in its delayed installation, these new pollen analyses provide the first pollen evidence of an anthropogenic factor particularly for the late Neolithic - early Bronze Age transition when increased human pressure (woodland clearances and presence of agricultural and grazing indicators) is evidenced. Different stages related to human activities are shown for the following periods. According to the pollen data, between ca. 2350-2100 cal. BP (ca. 400-150 cal. BC), the second Iron Age, and more particularly, the 4th-2nd centuries BC, represents an important threshold in the shaping of this medium mountain cultural landscape. Large beech-oak forest clearances are related to an important agropastoral extension which continues to increase during the beginning of the Roman period.
Landscape partitioning by nocturnal rodent assemblages in the Llanos de Ojuelos, in Mexico's Central High Plateau
15 juin 2011
Aim The Llanos de Ojuelos in Mexico's Central High Plateau supports unique Opuntia scrublands and the southernmost Chihuahuan grasslands. Although human activities have modified strongly its landscape and impacted its biodiversity at an unknown scale, such impacts are poorly known. We aimed at understanding how nocturnal rodent species distributed across the landscape and formed assemblages and on the role and integration of the different habitats at the landscape level. Location The study was carried out at 43 sites in a study area of approximately 3350 km2 in the Llanos de Ojuelos. Methods During the Spring of 2008, we surveyed nocturnal rodents, through live-trapping. We redefined habitat classes based on log-linear multinomial regressions of rodent captures. Species rarefaction curves and true alpha, beta and gamma diversities were calculated for the different habitat classes. A map of the different habitats was constructed based on Landsat imagery. Results We captured 458 individuals of 20 rodent species. Multinomial regressions caused the merger of 11 a priori defined habitat classes into 7. Leguminous scrub and mixed nopaleras, both secondary habitats, had the highest alpha and gamma diversity values. Closed arboreal nopaleras and grasslands had the highest within-habitat variability (1Db) and the lowest area coverage. Withinhabitat 1Db was larger than landscape 1Db, because of the great overlap in rodent assemblage composition between the habitats. Main conclusions There are no 'typical' rodent assemblages per habitat class, but they are organized loosely and have fuzzy borders. Rodent community organization was highly species-centred. At the landscape level, secondary habitats have a profound effect on rodent diversity and should be included in management schemes for biological conservation. The most endangered habitats seem to be the closed arboreal nopaleras and grasslands. Any conservation efforts must consider their conservation and an increase in the size of remaining patches.
Exposure to moulds and actinomycetes in Alpine farms: A nested environmental study of the PASTURE cohort.
10 juin 2011
Several studies have suggested that children exposed to a farm environment are protected against allergies and asthma. The present work is an environmental study nested within the PASTURE cohort and includes 97 farmers and 74 non-farmers in three regions of the Alpine Arc (Switzerland, France and Germany). The objectives were to determine and compare the fungi and actinomycetes present in farming and non-farming environments (children's bedrooms and cowsheds), and to identify the agricultural practices associated with an increase in airborne fungi and actinomycetes in cowsheds. Air samples were collected by air pump and were analysed by culture and by direct counting of spores on membranes. During their stay in bedrooms, children living on farms were exposed to significantly greater amounts of Absidia spp., Eurotium spp., Cladosporium spp., Penicillium spp. and mesophilic actinomycetes than children who did not live on farms. Depending on the season, the levels of moulds, yeasts and actinomycetes were from 14 to 82 times higher in cowsheds before feeding the cattle than in children's bedrooms, and from 12 to 464 times higher in cowsheds after feeding than in children's bedrooms. Feeding cattle in cowsheds was associated with a significant peak in airborne moulds and actinomycetes, and this peak was higher in winter than in summer. Silage distribution was associated with low amounts of moulds and actinomycetes. Other significant agricultural factors were the type of cowshed, cowshed volume, method of food distribution to cattle and use of fresh grass. An assessment of the microbiological diversity on farms and in children's rooms may help to determine the factors protecting children from asthma and atopic diseases.
Thermobarometry of metasomatized rocks
3 juin 2011
Quantification of the physical conditions of metasomatism is essential because it gives us a direct information on the P-T conditions of the passage of fluids through the rock. However, application of thermobarometry on metasomatized rocks is not without pitfalls. Like for "normal"metamorphic rocks, a major difficulty is to select minerals that were in equilibrium during their crystallization. This essential task is particularly difficult in metasomatized rocks because, firstly, it is difficult to distinguish textures like reactions and mineral zoning produced by change in P-T conditions from those due to fluid-rock interactions and associated change in bulk composition. Secondly, the equilibrium volume on metasomatized rocks varies significantly, from micron to hand-sample scale, depending on the amount of fluid involved and the nature of fluid transport mechanisms (pervasive or focused). Equivocal localized reaction textures and chemical zoning can be produced when equilibrium is achieved only at the micron scale at the interface between the fluid and the precipitating products. Pressure and temperature estimations can be accomplished through conventional thermobarometry (reverse modeling) and/or pseudosection thermobarometry (forward modeling), however we emphasize that this later technique provides essential information not available through conventional thermobarometry in metasomatized rocks. For instance, P-T-X pseudosections can be used to explore the effects of mass transfer (X) on phase relations. To highlight these pitfalls and give some recommendations on the application of thermobarometry on metasomatized rocks, we use three examples where metasomatism has been described and thermobarometry successfully applied. We conclude with a straightforward statement that application of thermobarometry on metasomatized rocks requires (1) a detailed mineralogical and textural investigation to select appropriate mineral compositions, (2) a geochemical analysis essential to define the relative and absolute mass change involved during the metasomatic event and (3) a forward modeling of the effects of mass-transfer on phase relations.
Evolution of Nurses' Social Representation of hospital Hygiene : from training to practice
26 mai 2011
Nurses' social representations of hospital hygiene were analyzed. A cross-sectional method was used to compare and analyze the social representations of the concept domain of "hospital hygiene" across three independent groups of participants (N=744). The groups included: (a) professional nurses (N=114); (b) student nurses (N=315); and (c) psychology students (N=315). Comparisons were drawn: (a) between professionals and students; and (b) between student nurse cohorts at three different levels (years) of training. The results show an ongoing evolution of the social representations of hospital hygiene during training and in the course of professional practice. The representation of hospital hygiene is structured around the element "cleanliness" at the beginning of training and around "asepsis" at the end of training. An increased specialization of vocabulary pertaining specifically to hospital hygiene is also observed. A comparative analysis between students and professionals shows a lower number of common lexical associations in the student group. A discussion of how these results are related to other research in cognitive ergonomics and the analyses of dialogues involving professional interactions between experts and novices is provided. Keywords: Social representations, hygiene, health, nosocomial infections, word association task, lexical analysis, similarity analysis.
Immuno-reactive proteins from Mycobacterium immunogenum useful for serodiagnosis of metalworking fluid hypersensitivity pneumonitis.
16 mai 2011
Metalworking fluid-associated hypersensitivity pneumonitis (MWF-HP) is a pulmonary disease caused by inhaling microorganisms present in the metalworking fluids used in the industrial sector. Mycobacterium immunogenum is the main etiological agent. Among the clinical, radiological and biological tools used for diagnosis, serological tests are important. The aim of this study was to identify immunogenic proteins in M. immunogenum and to use recombinant antigens for serological diagnosis of MWF-HP. Immunogenic proteins were detected by two-dimensional Western blot and candidate proteins were identified by mass spectrometry. Recombinant antigens were expressed in Escherichia coli and tested by enzyme-linked immunosorbent assay (ELISA) with the sera of 14 subjects with MWF-HP and 12 asymptomatic controls exposed to M. immunogenum. From the 350 spots visualized by two-dimensional gel electrophoresis with M. immunogenum extract, 6 immunogenic proteins were selected to be expressed as recombinant antigens. Acyl-CoA dehydrogenase antigen allowed for the best discrimination of MWF-HP cases against controls with an area under the receiver operating characteristics (ROC) curve of 0.930 (95% CI=0.820-1), a sensitivity of 100% and a specificity of 83% for the optimum threshold. Other recombinant antigens correspond to acyl-CoA dehydrogenase FadE, cytosol aminopeptidase, dihydrolipoyl dehydrogenase, serine hydroxymethyltransferase and superoxide dismutase. This is the first time that recombinant antigens have been used for the serodiagnosis of hypersensitivity pneumonitis. The availability of recombinant antigens makes it possible to develop standardized serological tests which in turn could simplify diagnosis, thus making it less invasive.
Dating low-temperature deformation by 40Ar/39Ar on white mica, insights from the Argentera-Mercantour Massif (SW Alps)
30 mars 2011
In order to date low-temperature deformation, intensely trained muscovite porphyroclasts and neocrystallized shear band phengite from greenschist-facies shear zones have been dated by 40Ar/39Ar method in the Argentera-Mercantour massif. Shear zones are featured by gradual mylonitization of a Variscan granite, gneiss and Permian pelite protolith (300-315Ma) during the Alpine orogenic event. Mineralogical and textural observations indicate that phengites and chlorites developed from biotite and plagioclase in fluid system during deformation following dissolution-transport-precipitation reactions of the type biotite + plagioclase + aqueous fluid = chlorite + albite + phengite + quartz + titanite + K-bearing fluid in the granite-gneiss mylonite. Contrariwise, phengite developed at the expense of clays following substitution reaction in pelite mylonite. Based on conventional thermobarometry on phengite and chlorite and Pressure-Temperature-aqueous fluid (P-T-MH2O) pseudosections calculated with shear zone bulk compositions, the conditions during shear deformation were estimated at 375±30 °C and 4.8-7±1 kbar in an H2O-satured system. In this low temperature environment, 40Ar/39Ar analysis of the Variscan muscovite for various grades of ductile strain intensity shows a limited 40Ar/39Ar isotopic resetting, all ages scattering between 296 and 315 Ma. Under conditions of intense ductile deformation and large scale fluid circulation, muscovite grains formed during the Variscan retain their much older ages. 40Ar/39Ar dating of very fine grained synkinematic phengite grains, neoformed during the Alpine history, give consistent plateau ages (34-20 Ma) for each shear zone. In detail, 40Ar excess can be detected in the pelite mylonitic sample where phengites crystallized by substitution process while the other mylonitic samples where phengites grow from fluid-induced reactions do not evidence any 40Ar excess. These results demonstrate that the 40Ar/39Ar dating of neocrystallized synkinematic white mica allows the determination of precise ages of deformation and fluid activity. Together with precise thermobarometry undertaken on the basis of mineral chemistry and whole-rock composition, 40Ar/39Ar dating of white mica leads to the reconstitution of precise depth-deformation history of low-grade (b400 °C) metamorphic units. At the Argentera-Mercantour massif scale, several stages of shear zone development at 15-21 km depth are dated between 33 and 20Ma. In the SE part of the massif shear zone ages are well constrained to be either (1) 33.6±0.6 Maor in the range (2) 26.8±0.7Ma-26.3±0.7 Ma. In the West of the massif, younger shear zone ages range between (3) 22.2±0.3 Ma and (4) 20.5±0.3 Ma.
Investigations of responses to metal pollution in land snail populations (Cantareus aspersus and Cepaea nemoralis) from a smelter-impacted area.
28 mars 2011
A cross-transplantation field experiment was performed to investigate about possible adaptation/acclimatization to metal pollution in common garden snail Cantareus aspersus (ex-Helix aspersa) and brown-lipped grove snail Cepaea nemoralis populations. Adults were collected from an area surrounding a former smelter (ME), highly polluted by trace metals (TMs) for decades, and from an unpolluted site (BE). Subadults of first generation (F1) were exposed in microcosms in a 28-day kinetic study. Four exposure sites were chosen around the smelter along a soil pollution gradient (vegetation and soil otherwise comparable). Bioaccumulation in snail soft tissues globally increased with soil contamination, with Cd, Pb and Zn concentrations reaching 271, 187, 5527 μg g(-1), respectively. Accumulation kinetic patterns were similar between snail species but C. nemoralis showed greater TM levels than C. aspersus. Some inter-population differences were revealed in TM accumulation (bioaccumulation factors, accumulation kinetics) but did not suggest consistent adaptive responses. We did not detect negative effects of TM exposure on snail condition (body weight, shell size, shell weight). ME C. aspersus snails produced heavier shells than BE snails under exposure to TMs at the highest level, suggesting an adaptive response. The protocol used in this study, however, did not allow unambiguously distinguishing whether this response was due to genetic adaptation or to maternal effects. Abnormal but reversible shell development of adult ME C. nemoralis suggested physiological acclimatization. Differences in responses to TMs between populations are observed for conchological parameters, not for bioaccumulation, with different strategies according to the species (acclimatization or adaptation/maternal effects).
Surface acoustic wave devices as passive buried sensors
16 mars 2011
Surface acoustic wave (SAW) devices are currently used as passive remote-controlled sensors for measuring various physical quantities through a wireless link. Among the two main classes of designs-resonator and delay line-the former has the advantage of providing narrow-band spectrum informations and hence appears compatible with an interrogation strategy complying with Industry-Scientific-Medical regulations in radio-frequency (rf) bands centered around 434, 866, or 915 MHz. Delay-line based sensors require larger bandwidths as they consists of a few interdigitated electrodes excited by short rf pulses with large instantaneous energy and short response delays but is compatible with existing equipment such as ground penetrating radar (GPR). We here demonstrate the measurement of temperature using the two configurations, particularly for long term monitoring using sensors buried in soil. Although we have demonstrated long term stability and robustness of packaged resonators and signal to noise ratio compatible with the expected application, the interrogation range (maximum 80 cm) is insufficient for most geology or geophysical purposes. We then focus on the use of delay lines, as the corresponding interrogation method is similar to the one used by GPR which allows for rf penetration distances ranging from a few meters to tens of meters and which operates in the lower rf range, depending on soil water content, permittivity, and conductivity. Assuming propagation losses in a pure dielectric medium with negligible conductivity (snow or ice), an interrogation distance of about 40 m is predicted, which overcomes the observed limits met when using interrogation methods specifically developed for wireless SAW sensors, and could partly comply with the above-mentioned applications. Although quite optimistic, this estimate is consistent with the signal to noise ratio observed during an experimental demonstration of the interrogation of a delay line buried at a depth of 5 m in snow.
Syn-collisional channel flow and exhumation of paleoproterozoic High Pressure rocks in the Trans-North China Orogen: the critical role of partial-melting and orogenic bending
14 mars 2011
Within the paleoproterozoic Trans-North China Orogen, the High-Pressure Belt (HPB) is made of high-pressure (~ 15 kbar) mafic granulites hosted in migmatitic gneisses. In this contribution, we document a set of structural analyses acquired over the whole HPB. We also proposed a morphological subdivision of the partially molten rocks that compose the HPB according to changes in melt fraction. A compilation of the P-T and radiochronological data carried out over the last 15 years is presented. The results highlight the concurrent effect of oroclinal bending and partial-melting in controlling the exhumation of the deeply buried continental crust. During ongoing compression of the thickening orogenic root, onset of partial-melting at peak metamorphism is responsible for a first strength drop that enhanced an eastward lateral flow. Radiometric ages show that the deep crust was partially molten over a 50 Ma lasting period during which it evolved in a diatexite core mantled by metatexites. This was responsible for a second strength drop with strain concentrated along the diatexite/metatexite boundaries, as exemplified by the newly documented Datong-Chengde Shear Zone, a ~ 400 km-long normal shear zone with a sinistral strike-slip component that accommodated the final uprise of the high-pressure rocks.
Ribosomal and mitochondrial DNA target for real-time PCR diagnosis of invasive aspergillosis
4 mars 2011
Pressure solution-fracturing interactions in weakly cohesive carbonate sediments and rocks: Example of the synsedimentary deformation of the Campanian chalk from the Mons Basin (Belgium)
21 février 2011
This paper documents the pressure solution-fracturing interactions in weakly cohesive carbonate sediments and rocks by studying the synsedimentary deformation of the Campanian chalk from the Mons Basin (Belgium). The present work shows that the development of a normal fault in a near-surface marine environment can promote significant mass transfers and volume changes in weakly cohesive micritic carbonate materials. The deformation corresponds to a mass redistribution from the deformed zones adjacent to the fault plane towards the outermost deformed zones. These mass transfers result from a faster return of the interstitial fluid pressure to an initial state within the outermost deformed zones. The deformation is rapidly controlled by the volume gains caused by the diffused rupture of grain contacts inside the outermost deformed zones and not by fracturing. Within the deformed zones adjacent to the fault plane, the mass losses and the related chemical compaction lead to a decrease in reservoir qualities of the material and the growth of a permeability barrier that rapidly restricts the flow of interstitial fluids towards the active fractures. Within the outermost deformed zones, the transport properties and the reservoir qualities of the material are maintained or increased.
Conditions and mechanism for the formation of iron-rich Montmorillonite in deep sea sediments (Costa Rica margin): Coupling high resolution mineralogical characterization and geochemical modeling
18 février 2011
Iron-rich smectite is commonly described in the diagenetic fraction of deep-sea sediment, as millimeter to centimeter aggregates dispersed in the sediment, or as a coating on sedimentary particles or nodules. This study examines several factors to elucidate formation mechanisms of a particular iron-rich smectite and its potential transformation to glauconite. The study combines a detailed mineralogical investigation on natural samples and a chemical modeling approach to assess mineralogical reactions and pathways. Transmission electron microscopy (TEM) observations and analytical electron microscopy (TEM–AEM) analyses were conducted on microtomed samples of millimeter- to centimeter-long green grains. These grains are widespread in pelagic calcareous sediment from the Costa Rica margin. They are composed of pyrites that are partially dissolved and are surrounded by amorphous or very poorly crystallized iron-rich particles. Iron-rich montmorillonite grows from an amorphous precursor and its formation requires the input of Si, O, Mg, K, Na and Ca; our results suggest that these inputs are supported by the dissolution of sedimentary phases such as volcanic glasses, siliceous fossils and silicates. Thermodynamic modeling of fluid–sediment interactions was conducted with the geochemical computer code PhreeqC, using mineralogical and pore fluid compositions from sediment samples and calculated estimates for thermodynamic constants of smectites that are not maintained by the computer code. Simulations confirm the possibility that the green grains are the product of pyrite alteration by seawater under oxidizing conditions. The extent of smectite production is controlled by the kinetics of pyrite dissolution and fluid migration. The absence of aluminum in the Costa Rica margin system explains the formation of an iron-rich montmorillonite instead of glauconite, whereas the presence of calcite that buffers the system explains the formation of an iron-rich montmorillonite instead of iron oxides.
Contrasting growth and adaptive responses of two oak species to flooding stress: role of non-symbiotic hemoglobin
31 janvier 2011
Soil flooding is an environmental constraint which will become increasingly important for forest ecosystems, affecting tree growth and regeneration. As a result, selection pressure will alter forest diversity and distribution by favoring tree species tolerant of soil oxygen deprivation. Sessile and pedunculate oaks are the most abundant oak species and they exhibit a strong differential tolerance to waterlogging. In order to gain some understanding of the mechanisms of tolerance of both species to hypoxia, we undertook the characterization of the physiological, morphological, cellular and molecular responses of both species to flooding stress. Our results indicate that pedunculate oak, the more tolerant species, succeeded in maintaining its growth, water status and photosynthetic activity at a higher level than sessile oak. Furthermore, pedunculate oak developed aerenchyma in its root cortex as well as adventitious roots. The later exhibited a strong accumulation of class1 non-symbiotic hemoglobin localized by in-situ hybridization in the protoderm and in some cortical cells. In conclusion, the higher tolerance of pedunculate oak to flooding was associated with an enhanced capacity to maintain photosynthesis and water homeostasis, coupled with the development of adaptive features (aerenchyma, adventitious roots) and with a higher expression of non-symbiotic hemoglobin in the roots.
Increased risk of non-Hodgkin lymphoma and serum organochlorine concentrations among neighbors of a municipal solid waste incinerator.
31 janvier 2011
Organochlorine chemicals may contribute to an increased risk of non-Hodgkin lymphoma (NHL) within non-occupationally exposed populations. Among these chemicals, dioxins and furans were mainly released by municipal solid waste incinerators (MSWIs) until a recent past in France, a source of exposure that is of public concern. We investigated organochlorines and the risk of NHL among neighbors of a French MSWI with high levels of dioxin emissions (Besançon, France), using serum concentrations to assess exposure. The study area consisted of three electoral wards, containing or surrounding the MSWI. Pesticides, dioxins, furans, and polychlorinated biphenyls (PCBs) were measured in the serum of 34 newly diagnosed NHL cases (2003-2005) and 34 controls. Risks of NHL associated with each lipid-corrected serum concentration were estimated using exact logistic regression. The pesticides β-hexachlorocyclohexane (odds ratio [OR]=1.05, 95% confidence interval [CI]=1.00-1.12, per 10ng/g lipid) and p,p' dichloro-diphenyl-trichloroethane (DDT) (OR=1.20, 95% CI=1.01-1.45, per 10ng/g lipid) were associated with NHL risk. Evidence indicated an increased NHL risk associated with cumulative WHO(1998)-toxic equivalency factor (TEQ) concentrations (dioxins, OR=1.12, 95% CI=1.03-1.26; furans, OR=1.16, 95% CI=1.03-1.35; dioxin-like PCBs, OR=1.04, 95% CI=1.00-1.07; and total TEQ, OR=1.04, 95% CI=1.01-1.05), as well as with non dioxin-like PCBs (OR=1.02, 95% CI=1.01-1.05, per 10ng/g lipid). Most congener-specific associations were statistically significant. This study provides strong and consistent support for an association between serum cumulative WHO(1998)-TEQ concentrations, at levels experienced by people residing in the vicinity of a polluting MSWI, and risk of NHL.
A real-time multiplex-nested PCR system for coprological diagnosis of Echinococcus multilocularis and host species.
30 janvier 2011
A hybridization probe-based real-time multiplex-nested PCR system was developed for the simultaneous detection of Echinococcus multilocularis and host species directly from faecal samples. Species identification was determined by melting curve analysis. Specificity was assessed by using DNA extracted from various cestodes (E. multilocularis, Echinococcus granulosus (G1), Echinococcus ortleppi, Echinococcus canadensis (G6, G7), Taenia crassiceps, Taenia hydatigena, Taenia mustelae, Taenia pisiformis, Taenia serialis, Taenia taeniaeformis, Mesocestoides leptothylacus), carnivores (Vulpes vulpes, Vulpes corsac, Vulpes ferrilata, Canis familiaris, Felis catus, Martes foina), Microtus arvalis and Arvicola terrestris. The analytical sensitivity was 10 fg, evaluated with serially diluted DNA of E. multilocularis to 10 μl total DNA solution from E. multilocularis-negative canid faeces. Based on a comparison of 47 dog samples from China, the proportion of the E. multilocularis-positive-tested samples by the real-time multiplex-nested PCR was moderately higher (38% vs. 30%) as when tested with a previously evaluated nested PCR with a sensitivity of 70-100%, depending on the number and gravidity status of worms present in the intestine (Dinkel et al., J Clin Microbiol 36:1871-1876, 1998). To assess the epidemiological applicability of this method, 227 canid faecal samples collected in the field were analysed. This newly developed real-time multiplex-nested PCR system is a specific, sensitive and reliable method for the detection of E. multilocularis and host species in faecal samples for epidemiological purposes.
The dechromatation step in wastewater treatment plants: fundamental role and optimization
28 janvier 2011
Heavy metals removal from industrial effluents by adsorption on crosslinked starch: chemical study and impact on water toxicity
28 janvier 2011
Effects of additional sorption treatment of industrial water discharge by cross-linked starch
28 janvier 2011
Contre: les composés organisuqes volatils d'origine fongique ont un impact sur la santé
28 janvier 2011
Retrospectif assessment of beta-d-glucan for presumptive diagnosis of fungal infections.
28 janvier 2011
Optimization of extraction procedure and chromatographic separation of glyphosate, glufosinate and aminomethylphosphonic acid in soil
26 janvier 2011
Analysing herbicides in soil is a complex issue that needs validation and optimization of existing methods. An extraction and analysis method was developed to assess concentrations of glyphosate, glufosinate and aminomethylphophonic acid (AMPA) in field soil samples. After testing extractions by accelerated solvent extraction and ultrasonic extraction, agitation was selected with the best recoveries. Water was preferred as solvent extraction because it resulted in a cleaner chromatogram with fewer impurities than was the case with alkaline solvents. Analysis was performed by FMOC pre-column derivatization followed by high-performance liquid chromatography (HPLC) on a 300Â mm C18 column which permitted enhanced separation and sensitivity than a 250Â mm C18 column and increased resistance than the NH2 column for soil samples. This extraction and analysis method allowing a minimum of steps before the injection in the HPLC with fluorescence detection is efficient and sensitive for a clay-loamy soil with detection limits of 103 µg kg-1 for glyphosate, 15 µg kg-1 for glufosinate and 16 µg kg-1 for AMPA in soil samples.
Simulation tools for decision support to adaptive forest management in Europe
22 janvier 2011
In forest management there is a tendency towards measuring more cost-effective and simulating more. In this context the development of reliable, user friendly forest simulators has become economically relevant. The objective of this perspective paper is to highlight the recent trends in forest simulation and to identify the remaining challenges to make forest simulation a reliable tool for forest policy and management. Experiences with forest simulators for various purposes in different geographical contexts illustrate how the important challenges of forest decision support can be addressed through flexible customization for different end-user categories, offering spatially explicit approaches at the landscape scale, and integrating empirical and mechanistic models in hybrid and bayesian simulation approaches. Recent development trends in forest simulation for decision support are mainly related to the ever increasing calculation speed and capacity of computers, facilitating the development of robust tools with comfortable user interface and realistic functions and options. Another trend is the combination of simulation tools with optimization and choice algorithms fading away the difference between simulators and decision support systems. The remaining challenges are basically in the high expectations of stakeholders concerning the ability of simulators to predict a range of outcomes in terms of ecosystem services and sustainability indicators, as well as the quality of their outcome in terms of output credibility to stakeholders. Need for accepted and realistic model validation and verification methods preferably using empirical data is crucial in this matter.
Un paysage agraire gallo-romain conservé dans le massif forestier de Haye (Meurthe-et-Moselle)
6 janvier 2011
Early Sr2+-induced effects on membrane potential, proton pumping- and ATP hydrolysis-activities of plasma membrane vesicles from maize root cells
4 janvier 2011
When released in plant environment, strontium (Sr2+) can be absorbed predominantly by the plant roots. As the plasma membrane of root cells is amongst the first barriers encountered by Sr2+ during its soil/plant transfer and the main entry point of Sr2+ into the roots, the main objective of this work aimed to enlighten on some of the Sr2+-induced effects at this level in Zea mays L. cv. “Liberal”. Thus this study focused on the Sr2+-induced changes on membrane potential of cortical root cells and on proton fluxes in maize roots, in order to determine whether the activity of some of the ion transport systems present in the plasma membrane of maize root cell could be among the first targets of Sr2+. We focused in particular on the plasma membrane H+-ATPase, known to be one of the major transport systems found in the plasmalemma where it generates a proton motive force (contributing to membrane potential maintaining, and providing energy for ion transport through membrane). The data presented here showed that Sr2+ triggered an early and transient membrane depolarisation whose magnitude and duration were dependent on the Sr2+-concentration. The time course pattern of a second longer lasting depolarisation could be examined in perspective with the Sr2+-induced decrease of the spontaneous proton extrusion observed in root tissues, suggesting a relationship between Sr2+- effects on membrane potential and H+ excretion. Furthermore, the inhibitory effect exerted by Sr2+ on the fusicoccin (FC)-enhanced proton extrusion strongly suggested an inhibition of the plasma membrane H+-ATPase. This hypothesis was supported by the inhibition induced by Sr2+ on proton pumping- and ATP hydrolysis-activities measured in plasma membrane vesicles (PMV) prepared from maize roots. Taken together the data reported here evidence that, with however a lower efficiency, Sr2+ behaved in a quite similar way to Ca2+ when inhibiting the H+-ATPase activity, and suggest that Sr2+ could partially mimic Ca2+ onto regulation of the H+-ATPase activity.
Fox defecation behaviour in relation to spatial distribution of voles in an urbanised area: An increasing risk of transmission of Echinococcus multilocularis?
12 décembre 2010
Urbanisation of alveolar echinococcosis is a new phenomenon that has been highlighted during the last few decades. It has thus become necessary to understand the dynamics of transmission of Echinococcus multilocularis in urbanised areas. Spatial heterogeneity of infection by E. multilocularis has been explained as the result of a multifactorial dependence of the transmission in which the factors depend on the scale of the investigation. The aim of this study was to assess, in an urbanised area, the effect of such environmental factors as season, habitat type and the level of urbanisation, on the availability of two major intermediate hosts (Microtus spp. and Arvicola terrestris), the distribution of red fox faeces and the distribution of E. multilocularis as determined by detection of coproantigens in faeces. Results of the study revealed higher densities of Microtus spp. in rural than in peri-urban areas. Moreover this species was highly aggregated in urban wasteland. Arvicola terrestris densities did not appear to be linked to the level of urbanisation or to the type of habitat studied. Distribution of faeces was positively linked to distance walked and to Microtus spp. and A. terrestris distributions whatever the level of urbanisation. Such a distribution pattern could enhance the transmission cycle in urban areas. The Copro-ELISA test results on faeces collected in the field revealed that ODs were significantly negatively correlated with the abundance of A. terrestris. The larger population densities of Microtus spp. found in urban wastelands and the well known predominance of Microtus spp. in the red fox diet in the region suggest that Microtus spp. may play a key role in urban transmission of the parasite in the study area.
Numerical Ecology with R
27 octobre 2010
Numerical Ecology with R provides a long-awaited bridge between a textbook in Numerical Ecology and the implementation of this discipline in the R language. After short theoretical overviews, the authors accompany the users through the exploration of the methods by means of applied and extensively commented examples. Users are invited to use this book as a teaching companion at the computer. The travel starts with exploratory approaches, proceeds with the construction of association matrices, then addresses three families of methods: clustering, unconstrained and canonical ordination, and spatial analysis. All the necessary data files, the scripts used in the chapters, as well as the extra R functions and packages written by the authors, can be downloaded from a web page accessible through the Springer web site (http://www.springer.com/978-1-4419-7975-9). This book is aimed at professional researchers, practitioners, graduate students and teachers in ecology, environmental science and engineering, and in related fields such as oceanography, molecular ecology, agriculture and soil science, who already have a background in general and multivariate statistics and wish to apply this knowledge to their data using the R language, as well as people willing to accompany their disciplinary learning with practical applications. People from other fields (e.g. geology, geography, paleoecology, phylogenetics, anthropology, the social and education sciences, etc.) may also benefit from the materials presented in this book. The three authors teach numerical ecology, both theoretical and practical, to a wide array of audiences, in regular courses in their Universities and in short courses given around the world. Daniel Borcard is lecturer of Biostatistics and Ecology and researcher in Numerical Ecology at Université de Montréal, Québec, Canada. François Gillet is professor of Community Ecology and Ecological Modelling at Université de Franche-Comté, Besançon, France. Pierre Legendre is professor of Quantitative Biology and Ecology at Université de Montréal, Fellow of the Royal Society of Canada, and ISI Highly Cited Researcher in Ecology/Environment.
Modelling natural disturbances in forest ecosystems: A review
27 octobre 2010
Natural disturbances play a key role in ecosystem dynamics and are important factors for sustainable forest ecosystem management. Quantitative models are frequently employed to tackle the complexities associated with disturbance processes. Here we review the wide variety of approaches to modelling natural disturbances in forest ecosystems, addressing the full spectrum of disturbance modelling from single events to integrated disturbance regimes. We applied a general, process-based framework founded in disturbance ecology to analyze modelling approaches for drought, wind, forest fires, insect pests and ungulate browsing. Modelling approaches were reviewed by disturbance agent and mechanism, and a set of general disturbance modelling concepts was deduced. We found that although the number of disturbance modelling approaches emerging over the last 15 years has increased strongly, statistical concepts for descriptive modelling are still largely prevalent over mechanistic concepts for explanatory and predictive applications. Yet, considering the increasing importance of disturbances for forest dynamics and ecosystem stewardship under anthropogenic climate change, the latter concepts are crucial tool for understanding and coping with change in forest ecosystems. Current challenges for disturbance modelling in forest ecosystems are thus (i) to overcome remaining limits in process understanding, (ii) to further a mechanistic foundation in disturbance modelling, (iii) to integrate multiple disturbance processes in dynamic ecosystem models for decision support in forest management, and (iv) to bring together scaling capabilities across several levels of organization with a representation of system complexity that captures the emergent behaviour of disturbance regimes.
Restoration of threatened arable weed communities in abandoned mountainous crop fields
21 décembre 2009
Arable fields maintaining species-rich weed communities have almost disappeared from European mountain areas due to agricultural extensification during the last decades. The restoration of arable weed communities have become an important issue in these habitats which have a large potential to contain rare and threatened (red-list) species. In a site in the Swiss Alps formerly managed for crop production, we investigated in experimental ploughed plots the 1-year effects of fertilizing, sowing a mixture of arable weed species and sowing a crop species (triticale) on the natural regeneration (species richness and cover) of arable weed and non-weed species. The high number of newly appeared arable weed species, of which 4 were red-list species, indicates that propagule availability was still important after about 50 years of arable field abandonment. Ploughed plots which did not receive any treatment and those with fertilization alone favoured the regeneration of both wild weed and non-weed species. The crop species limited, but not inhibited, the recovery success of weed and non-weed species and this negative effect tended to be higher under fertilization. Sowing of arable weed seeds decreased the natural regeneration of both weeds and non-weeds in absence of triticale. Our results show that ploughing is a promising method to successfully restore the weed community in abandoned arable mountain areas. Moreover, the sowing of weed species in combination with a crop species might produce sustainable food and restore and maintain the diversity of threatened arable weeds at the same time.