7-ethylresorufin O-deethylase activity and level of DNA-adducts in trout treated with benzo(a)pyrene     

Jean-Franois Masfaraud  Annie Pfohl-Leszkowic  Christian Malaveille  Grard Keith  Gilles Monod 《Marine environmental research》1992,34(1-4)

In fish, as well as in mammals, it is well known that the cytochrome P450-dependent oxidative metabolism of xenobiotics can generate DNA-reactive species. Moreover, this metabolism is known to be inducible by several compounds of environmental significance, such as polychlorobiphenyls, polycyclic aromatic hydrocarbons (PAHs) and dioxins. Consequently, we studied the relationship between the degree of induction of the cytochrome P4501A, expressed as that of 7-ethylresorufin O-deethylase (EROD) activity, and the level of DNA-adducts, using the post-labelling assay, in the liver of rainbow trout exposed to benzo(a)pyrene (a representative PAH). The results showed a significant 2- to 4-fold increase in EROD activity 2, 4 and 8 days after treatment, paralleled by an increase in DNA-adduct levels. This work further emphasizes the involvement of cytochrome P4501A in the metabolism of benzo(a)pyrene into genotoxic metabolites in rainbow trout.  相似文献   

The high temperature reaction zone of the Oman ophiolite: new field data,microthermometry of fluid inclusions,PIXE analyses and oxygen isotopic ratios     

Juteau  Thierry  Manac'h  Gilles  Moreau  Olivier  Lécuyer  Christophe  Ramboz  Claire 《Marine Geophysical Researches》2000,21(3-4):351-385

Marine Geophysical Research - The present study is focused on the so-called High Temprature Reaction Zone of the Oman ophiolite, a thin zone located between the roots of the sheeted dyke complex...  相似文献   

Editorial     

Gilles La Roche 《Marine environmental research》1979,2(4):251-253

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Landslide databases in the Geological Surveys of Europe     

Gerardo Herrera  Rosa María Mateos  Juan Carlos García-Davalillo  Gilles Grandjean  Eleftheria Poyiadji  Raluca Maftei  Tatiana-Constantina Filipciuc  Mateja Jemec Auflič  Jernej Jež  Laszlo Podolszki  Alessandro Trigila  Carla Iadanza  Hugo Raetzo  Arben Kociu  Maria Przyłucka  Marcin Kułak  Michael Sheehy  Xavier M. Pellicer  Charise McKeown  Graham Ryan  Veronika Kopačková  Michaela Frei  Dirk Kuhn  Reginald L. Hermanns  Niki Koulermou  Colby A. Smith  Mats Engdahl  Pere Buxó  Marta Gonzalez  Claire Dashwood  Helen Reeves  Francesca Cigna  Pavel Liščák  Peter Pauditš  Vidas Mikulėnas  Vedad Demir  Margus Raha  Lídia Quental  Cvjetko Sandić  Balazs Fusi  Odd Are Jensen 《Landslides》2018,15(2):359-379

Landslides are one of the most widespread geohazards in Europe, producing significant social and economic impacts. Rapid population growth in urban areas throughout many countries in Europe and extreme climatic scenarios can considerably increase landslide risk in the near future. Variability exists between European countries in both the statutory treatment of landslide risk and the use of official assessment guidelines. This suggests that a European Landslides Directive that provides a common legal framework for dealing with landslides is necessary. With this long-term goal in mind, this work analyzes the landslide databases from the Geological Surveys of Europe focusing on their interoperability and completeness. The same landslide classification could be used for the 849,543 landslide records from the Geological Surveys, from which 36% are slides, 10% are falls, 20% are flows, 11% are complex slides, and 24% either remain unclassified or correspond to another typology. Most of them are mapped with the same symbol at a scale of 1:25,000 or greater, providing the necessary information to elaborate European-scale susceptibility maps for each landslide type. A landslide density map was produced for the available records from the Geological Surveys (LANDEN map) showing, for the first time, 210,544 km² landslide-prone areas and 23,681 administrative areas where the Geological Surveys from Europe have recorded landslides. The comparison of this map with the European landslide susceptibility map (ELSUS 1000 v1) is successful for most of the territory (69.7%) showing certain variability between countries. This comparison also permitted the identification of 0.98 Mkm² (28.9%) of landslide-susceptible areas without records from the Geological Surveys, which have been used to evaluate the landslide database completeness. The estimated completeness of the landslide databases (LDBs) from the Geological Surveys is 17%, varying between 1 and 55%. This variability is due to the different landslide strategies adopted by each country. In some of them, landslide mapping is systematic; others only record damaging landslides, whereas in others, landslide maps are only available for certain regions or local areas. Moreover, in most of the countries, LDBs from the Geological Surveys co-exist with others owned by a variety of public institutions producing LDBs at variable scales and formats. Hence, a greater coordination effort should be made by all the institutions working in landslide mapping to increase data integration and harmonization.  相似文献   

Microbial deposits in the aftermath of the end‐Permian mass extinction: A diverging case from the Mineral Mountains (Utah,USA)          下载免费PDF全文

Emmanuelle Vennin  Nicolas Olivier  Arnaud Brayard  Ivan Bour  Christophe Thomazo  Gilles Escarguel  Emmanuel Fara  Kevin G. Bylund  James F. Jenks  Daniel A. Stephen  Richard Hofmann 《Sedimentology》2015,62(3):753-792

The Lower Triassic Mineral Mountains area (Utah, USA) preserves diversified Smithian and Spathian reefs and bioaccumulations that contain fenestral‐microbialites and various benthic and pelagic organisms. Ecological and environmental changes during the Early Triassic are commonly assumed to be associated with numerous perturbations (productivity changes, acidifica‐tion, redox changes, hypercapnia, eustatism and temperature changes) post‐dating the Permian–Triassic mass extinction. New data acquired in the Mineral Mountains sediments provide evidence to decipher the relationships between depositional environments and the growth and distribution of microbial structures. These data also help to understand better the controlling factors acting upon sedimentation and community turnovers through the Smithian–early Spathian. The studied section records a large‐scale depositional sequence during the Dienerian(?)–Spathian interval. During the transgression, depositional environments evolved from a coastal bay with continental deposits to intertidal fenestral–microbial limestones, shallow subtidal marine sponge–microbial reefs to deep subtidal mud‐dominated limestones. Storm‐induced deposits, microbialite–sponge reefs and shallow subtidal deposits indicate the regression. Three microbialite associations occur in ascending order: (i) a red beds microbialite association deposited in low‐energy hypersaline supratidal conditions where microbialites consist of microbial mats and poorly preserved microbially induced sedimentary structure; (ii) a Smithian microbialite association formed in moderate to high‐energy, tidal conditions where microbialites include stromatolites and associated carbonate grains (oncoids, ooids and peloids); and (iii) a Spathian microbialite association developed in low‐energy offshore conditions that is preserved as multiple decimetre thick isolated domes and coalescent domes. Data indicate that the morphologies of the three microbialite associations are controlled primarily by accommodation, hydrodynamics, bathymetry and grain supply. This study suggests that microbial constructions are controlled by changes between trapping and binding versus precipitation processes in variable hydrodynamic conditions. Due to the presence of numerous metazoans associated with microbialites throughout the Smithian increase in accommodation and Spathian decrease in accommodation, the commonly assumed anachronistic character of the Early Triassic microbialites and the traditional view of prolonged deleterious conditions during the Early Triassic time interval is questioned.  相似文献   

Evolution of depositional settings in the Torrey area during the Smithian (Early Triassic,Utah, USA) and their significance for the biotic recovery     

Nicolas Olivier  Arnaud Brayard  Emmanuelle Vennin  Gilles Escarguel  Emmanuel Fara  Kevin G. Bylund  James F. Jenks  Gwnaël Caravaca  Daniel A. Stephen 《Geological Journal》2016,51(4):600-626

This work focuses on well‐exposed Lower Triassic sedimentary rocks in the area of Torrey (south‐central Utah, USA). The studied Smithian 8 deposits record a large‐scale third‐order sea‐level cycle, which permits a detailed reconstruction of the evolution of depositional settings. During the middle Smithian, peritidal microbial limestones associated with a rather low‐diversity benthic fauna were deposited seaward of the tidal flat siliciclastic red beds. Associated with siliceous sponges, microbial limestones formed small m‐scale patch reefs. During the late middle to late Smithian interval, the sedimentary system is characterized by tidal flat dolostones of an interior platform, ooid‐bioclastic deposits of a tide‐dominated shoal complex, and mid‐shelf bioclastic limestones. Microbial deposits, corresponding to sparse stromatolites formed in the interior platform, are contemporaneous with a well‐diversified marine fauna living in a seaward shoal complex and mid‐shelf area. The nature and distribution of these Smithian microbial deposits are not related to any particular deleterious environmental condition, highlighting that observed patterns of biotic recovery after the end‐Permian mass extinction were directly influenced by depositional settings. Facies evolution and stratal stacking patterns allow us to identify large, medium and small‐scale, as well as elementary depositional sequences. Large‐ and medium‐scale sequences are consistent with sea‐level changes, whereas small‐scale and elementary sequences are better explained by autocyclic processes. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Liquid water uptake in unconfined Callovo Oxfordian clay-rock studied with neutron and X-ray imaging     

Stavropoulou  Eleni  Andò  Edward  Tengattini  Alessandro  Briffaut  Matthieu  Dufour  Frédéric  Atkins  Duncan  Armand  Gilles 《Acta Geotechnica》2019,14(1):19-33

The Callovo Oxfordian clay-rock (COx) is studied in France for the disposal of radioactive waste, because of its extremely low permeability. This host rock is governed by a hydromechanical coupling of high complexity. This paper presents an experimental study into the mechanisms of water uptake in small, unconfined, prismatic specimens of COx, motivated by the comprehension of cracking observed during concrete/COx interface sample preparation. Water uptake is monitored using both X-ray tomography and neutron radiography, the combination of these imaging techniques allowing material deformation and water arrival to be quantified, respectively. Given the speed of water entry and crack propagation, relatively fast imaging is required: 5-min X-ray tomographies and 10-s neutron radiographs are used. In this study, pairs of similar COx samples from the same core are tested separately with each imaging technique. Two different orientations with respect to the core are also investigated. Analysis of the resulting images yields with micro- and macro-scale insights into hydromechanical mechanisms to be obtained. This allows the cracking to be interpreted as a rapid breakdown in capillary suction (supposed large both to drying and rebound from in situ stress state) due to water arrival, which in turn causes a loss of effective stress, allowing cracks to propagate and deliver water further into the material.

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Pearl oysters Pinctada margaritifera grazing on natural plankton in Ahe atoll lagoon (Tuamotu archipelago, French Polynesia)   总被引：1，自引：0，他引：1  

Fournier J  Dupuy C  Bouvy M  Couraudon-Réale M  Charpy L  Pouvreau S  Le Moullac G  Le Pennec M  Cochard JC 《Marine pollution bulletin》2012,65(10-12):490-499

In atoll lagoons of French Polynesia, growth and reproduction of pearl oysters are mainly driven by plankton concentration. However, the actual diet of black-lip pearl oysters Pinctada margaritifera in these lagoons is poorly known. To fill this gap, we used the flow through chamber method to measure clearance rates of P. margaritifera in Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia). We found: (i) that pearl oysters cleared plankton at a rate that was positively related to plankton biovolume, (ii) that nanoflagellates were the main source of carbon for the pearl oysters, and (iii) that the quantity and origin of carbon filtrated by pearl oysters was highly dependent on the concentration and composition of plankton. These results provide essential elements for the comprehension of growth and reproduction variability of pearl oysters in atoll lagoons of French Polynesia.  相似文献   

Characterizing and Locating Very Weak (−2.2 ≥ M L ≥ −3.4) Induced Seismicity in Unstable Sandstone Cliffs by Nanoseismic Monitoring     

Hillel Gilles Wust-Bloch 《Pure and Applied Geophysics》2010,167(1-2):153-167

Unloaded natural rock masses are known to generate seismic signals (Green et al., 2006; Hainzl et al., 2006; Husen et al., 2007; Kraft et al., 2006). Following a 1,000 m³ mass failure into the Mediterranean Sea, centimeter-wide tensile cracks were observed to have developed on top of an unstable segment of the coastal cliff. Nanoseismic monitoring techniques (Wust-Bloch and Joswig, 2006; Joswig, 2008), which function as a seismic microscope for extremely weak seismic events, were applied to verify whether brittle failure is still generated within this unconsolidated sandstone mass and to determine whether it can be detected. Sixteen days after the initial mass failure, three small-aperture sparse arrays (Seismic Navigation Systems-SNS) were deployed on top of this 40-m high shoreline cliff. This paper analyzes dozens of spiky nanoseismic (?2.2 ≥ M _L ≥ ?3.4) signals recorded over one night in continuous mode (at 200 Hz) at very short slant distances (3–67 m). Waveform characterization by sonogram analysis (Joswig, 2008) shows that these spiky signals are all short in duration (>0.5 s). Most of their signal energy is concentrated in the 10–75 Hz frequency range and the waveforms display high signal similarity. The detection threshold of the data set reaches M _L ?3.4 at 15 m and M _L ?2.7 at 67 m. The spatial distribution of source signals shows 3-D clustering within 10 m from the cliff edge. The time distribution of M _L magnitude does not display any decay pattern of M _L over time. This corroborates an unusual event decay over time (modified Omori’s law), whereby an initial quiet period is followed by regained activity, which then fades again. The polarization of maximal waveform amplitude was used to estimate spatial stress distribution. The orientation of ellipses displaying maximal signal energy is consistent with that of tensile cracks observed in the field and agrees with rock mechanics predictions. The M _L– surface rupture length relationship displayed by our data fits a constant-slope extrapolation of empirical data collected by Wells and Coppersmith (1994) for normal fault features at much larger scale. Signal characterization and location as well as the absence of direct anthropogenic noise sources near the monitoring site, all indicate that these nanoseismic signals are generated by brittle failure within the top section of the cliff. The atypical event decay over time that was observed suggests that the cliff material is undergoing post-collapse bulk strain accommodation. This feasibility study demonstrates the potential of nanoseismic monitoring in rapidly detecting, locating and analyzing brittle failure generated within unconsolidated material before total collapse occurs.  相似文献   

Distributed approximation of open-channel flow routing accounting for backwater effects   总被引：2，自引：0，他引：2  

Simon Munier  Xavier Litrico  Gilles Belaud  Pierre-Olivier Malaterre   《Advances in water resources》2008,31(12):1590-1602

In this article, we propose a new model, called LBLR for Linear Backwater Lag-and-Route, which approximates the Saint-Venant equations linearized around a non-uniform flow in a finite channel (with a downstream boundary condition). A classical frequency approach is used to build the distributed Saint-Venant transfer function providing the discharge at any point in the channel in the Laplace domain with respect to the upstream discharge. The moment matching method is used to match a second-order-with-delay model on the theoretical distributed Saint-Venant transfer function. Model parameters are then expressed analytically as functions of the pool characteristics. The proposed model efficiently accounts for the effects of downstream boundary condition on the channel dynamics.  相似文献