Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : Consumption of marine organisms represents one of the main exposure sources of contaminants for human populations. To obtain a global view of the contamination in commercial fish in the NW Mediterranean Sea, we analysed four types of priority contaminants (PCBs, PBDEs, Hg and Cs-137) in the European hake, Merluccius merluccius, from the Gulf of Lions in relation with organism's trophic level (delta N-15). All contaminants presented a significant increase in concentration in hake muscle with trophic level. However, obvious differences between contaminants were evidenced. Biomagnification factors (BMF and FWMF) along the hake food web were higher for Hg and CB-153 than for BDE-47 and Cs-137, and increase in contaminant concentration with trophic level occurred at different rates depending on contaminants. Such differences of biomagnification patterns can be related to physico-chemical properties of the different contaminants. (C) 2012 Elsevier Ltd. All rights reserved.
Marine Pollution Bulletin (0025-326X) (Pergamon-elsevier Science Ltd), 2012-05 , Vol. 64 , N. 5 , P. 974-983

Droits : 2012 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00085/19583/17484.pdf
DOI:10.1016/j.marpolbul.2012.02.014
http://archimer.ifremer.fr/doc/00085/19583/

Éditeur(s) : Copernicus Gesellschaft Mbh
Résumé : During the GWADASEIS cruise (Lesser Antilles volcanic arc, February-March 2009) a very high resolution (VHR) seismic-reflection survey was performed in order to constrain Late Quaternary to Present faulting. The profiles we obtained evidence frequent "ponding" of reworked sediments in the deepest areas, similar to the deposition of Mediterranean "homogenites". These bodies are acoustically transparent (few ms t.w.t. thick) and are often deposited on the hanging walls of dominantly normal faults, at the base of scarps. Their thickness appears sufficient to compensate (i.e. bury) co-seismic scarps between successive earthquakes, resulting in a flat and horizontal sea floor through time. In a selected area (offshore Montserrat and Nevis islands), piston coring (4 to 7m long) was dedicated to a sedimentological analysis of the most recent of these particular layers. It corresponds to non-stratified homogenous calcareous silty sand (reworked calcareous plankton and minor volcanoclastics). This layer can be up to 2 m thick, and overlies fine-grained hemipelagites. The upper centimeters of the latter represent the normal RedOx water/sediment interface. Pb-210 and Cs-137 activities lack in the massive sands, while a normal profile of unsupported Pb-210 decrease is observed in the hemipelagite below, together with a Cs-137 peak corresponding to the Atmospheric Nuclear Experiments (1962). The RedOx level was thus capped by a recent instantaneous major sedimentary event considered as post-1970 AD; candidate seismic events to explain this sedimentary deposits are either the 16 March 1985 earthquake or the 8 October 1974 one (M-w = 6.3 and M-w = 7.4, respectively). This leads to consider that the syntectonic sedimentation in this area is not continuous but results from accumulation of thick homogenites deposited after the earthquakes (as observed in the following weeks after Haiti January 2010 event, McHugh et al., 2011). The existence of such deposits suggests that, in the area of study, vertical throw likely results from cumulated effects of separated earthquakes rather than from aseismic creep. Examination of VHR profiles shows that all major co-seismic offsets are recorded in the fault growth sequence and that co-seismic offsets can be precisely estimated. By using a sedimentation rate deduced from Pb-210 decrease curve (0.5 mmyr(-1)) and taking into account minor reworking events detected in cores, we show that the Redonda system may have been responsible for five > M-6 events during the last 34 000 yr. The approach presented in this work differs from fault activity analyses using displaced sets of isochronous surfaces and postulating co-seismic offsets. Combining VHR seismic imagery and coring we can decipher co-seismic vs. slow continuous displacement, and thus actually estimate the amplitude and the time distribution of major co-seismic offsets.
Natural Hazards And Earth System Sciences (1561-8633) (Copernicus Gesellschaft Mbh), 2012 , Vol. 12 , N. 5 , P. 1755-1767

Droits : Author(s) 2012. CC Attribution 3.0 License.
http://archimer.ifremer.fr/doc/00089/20040/21990.pdf
DOI:10.5194/nhess-12-1755-2012
http://archimer.ifremer.fr/doc/00089/20040/

Éditeur(s) : HAL CCSD University of Arizona
Résumé : International audience
Taiwan is a young and seismically active mountain belt, where a series of strong earthquakes (M>7) have occurred over the past hundred years. Identifying historical earthquakes around Taiwan is a key to better constrain the geodynamic of this active region. Sedimentological and geochemical analyses of surface sediments from one station offshore east Taiwan revealed the presence of coarse-grained layers interpreted as turbidites. The age of these layers have been determined by 210Pb, 137Cs, and 241Am chronology. Dating of the three most recent turbidites provides ages of AD 2001±3, AD 1950±5, and AD 1928±10. The results show striking temporal correspondence of turbidite layers to large (M≥6.8) earthquakes recorded in the region since the 20th century. The chronologies of sediment layers lead us to believe that turbidites resulted from the 2003 Taitung earthquake (M 6.8), the 1951 Chengkong earthquake (M 7.1), and the 1935 Lutao earthquake (M 7.0), respectively. Such a good correlation between turbidites and high-magnitude (M≥6.8) historical and instrumental seismic events suggests that turbidite paleoseismology constitutes a valuable tool for earthquake assessment in the eastern Taiwan margin. Moreover, the modern reservoir radiocarbon age and the regional marine reservoir correction (ΔR) of the Kuroshio Current off Taiwan were estimated by comparing accelerator mass spectrometry (AMS) 14C ages with ages derived from corrected 210Pb profiles and historical accounts of identifiable seismic events. Such a determination is important to calibrate the 14C ages of marine materials for accurate comparison of marine and continental geological records. Our calculated mean ΔR value of 232±54 14C yr (n=2) is higher than its modern value of 86±40 14C yr. This high value can be explained by the presence of local upwelling cells and turbulence in the Kuroshio Current, north of Green Island. These upwelling cells bring 14C-depleted water to the surface, resulting in an increase of the modern ΔR value in this portion of the Kuroshio Current.
ISSN: 0033-8222

hal-01306986
https://hal.archives-ouvertes.fr/hal-01306986
DOI : 10.1017/RDC.2015.3

Éditeur(s) : HAL CCSD Copernicus Publications on behalf of the European Geosciences Union
Résumé : International audience
During the GWADASEIS cruise (Lesser Antilles volcanic arc, February–March 2009) a very high resolution (VHR) seismic-reflection survey was performed in order to constrain Late Quaternary to Present faulting. The profiles we obtained evidence frequent " ponding " of reworked sediments in the deepest areas, similar to the deposition of Mediterranean " homogenites ". These bodies are acoustically transparent (few ms t.w.t. thick) and are often deposited on the hanging walls of dominantly normal faults, at the base of scarps. Their thickness appears sufficient to compensate (i.e. bury) co-seismic scarps between successive earthquakes, resulting in a flat and horizontal sea floor through time. In a selected area (offshore Montserrat and Nevis islands), piston coring (4 to 7 m long) was dedicated to a sedimento-logical analysis of the most recent of these particular layers. It corresponds to non-stratified homogenous calcareous silty sand (reworked calcareous plankton and minor volcanoclas-tics). This layer can be up to 2 m thick, and overlies fine-grained hemipelagites. The upper centimeters of the latter represent the normal RedOx water/sediment interface. 210 Pb and 137 Cs activities lack in the massive sands, while a normal profile of unsupported 210 Pb decrease is observed in the hemipelagite below, together with a 137 Cs peak corresponding to the Atmospheric Nuclear Experiments (1962). The RedOx level was thus capped by a recent instantaneous major sedimentary event considered as post-1970 AD; candidate seismic events to explain this sedimentary deposits are either the 16 March 1985 earthquake or the 8 October 1974 one (M w = 6.3 and M w = 7.4, respectively). This leads to consider that the syntectonic sedimentation in this area is not continuous but results from accumulation of thick homogen-ites deposited after the earthquakes (as observed in the following weeks after Haiti January 2010 event, McHugh et al., 2011). The existence of such deposits suggests that, in the area of study, vertical throw likely results from cu-mulated effects of separated earthquakes rather than from aseismic creep. Examination of VHR profiles shows that all major co-seismic offsets are recorded in the fault growth sequence and that co-seismic offsets can be precisely estimated. By using a sedimentation rate deduced from 210 Pb decrease curve (0.5 mm yr −1) and taking into account minor reworking events detected in cores, we show that the Redonda system may have been responsible for five > M 6 events during the last 34 000 yr. The approach presented in this work differs from fault activity analyses using displaced sets of isochronous surfaces and postulating co-seismic offsets. Combining VHR seismic imagery and coring we can decipher co-seismic vs. slow continuous displacement, and thus actually estimate the amplitude and the time distribution of major co-seismic offsets.
Natural Hazards and Earth System Science

insu-01585969
https://hal-insu.archives-ouvertes.fr/insu-01585969
https://hal-insu.archives-ouvertes.fr/insu-01585969/document
https://hal-insu.archives-ouvertes.fr/insu-01585969/file/nhess-12-1755-2012-beck.pdf
DOI : 10.5194/nhess-12-1755-2012

Éditeur(s) : HAL CCSD Elsevier
Résumé : Finding records of past catastrophic storm events is essential to evaluate the long term climatic evolution in a given coastal area. This question has been addressed by the study of sediment cores sampled in a small coastal lagoon of the French Mediterranean coast (Pierre Blanche lagoon). Two cores were studied in detail and revealed the presence of three main storm events. The sedimentation rates calculated using the CFCS Pb-210 model, in agreement with Cs-137 data, are 3 +/- 0.4 and 4.2 +/- 0.7 mm y(-1) near the border and in the center of the lagoon respectively. This suggests that the 0.6 m deep lagoon could be filled with sediments over the next 150 yr. Our study shows that storm events can be characterized in sedimentary sequences identified by facies, grain size and faunal assemblages (lagoonal and marine species). Comparison of Pb-210, C-14 chronology and historical accounts suggest that the three identified storm events took place in 1742, 1839 and 1893 A.D. (i.e. about one catastrophic event per century).
ISSN: 0025-3227

hal-00411189
https://hal.archives-ouvertes.fr/hal-00411189
DOI : 10.1016/j.margeo.2008.03.001

Éditeur(s) : HAL CCSD Société géologique de France
Résumé : International audience
The central part of the Gulf of Lions shoreline is characterized by many coastal wetlands that resulted from the interaction between a process of shoreline regularization by migrations of littoral barriers and a slow filling of the back-barrier areas by the riverine and marine inputs. Analyses of Late-Holocene deposits with a very high-resolution multi-proxy study of two sediment cores, allow us to reconstruct the evolution of this coastal system. Two main Holocene sediment units are identified overlying a Pliocene carbonate continental formation. The lower unit consists of sandy and pebbly marine sediments deposited around 7800 B.P., during the final stand of the last sea level rise. Just above, the upper unit displays lagoonal grey clay silts with shells and some intercalated layers of silty sands related to paleostorm events. The age model was established from radiocarbon dating, for the oldest part of the core. Over the last century, sedimentation rates were calculated using the CFCS Pb-210 model, together with Cs-137 data. Radiocarbon data show an increase in he accumulation rate from the base to the top of cores. Marine sand units related to the last transgressive deposit allow to refine the curve of Holocene post-glacial sea level rise. Sedimentological and faunal analyses associated with chronological data provide a means for reconstructing the Late-Holocene paleoenvironments along this part of the coast and suggest that the final closure of the coastal lagoon by the sandy barrier occurred at around 730 +/- 120 yr cal B.P. The beginning of this closure, together with the progradation of the coastal plain, could be responsible for the decline in economic activity of the Lattara harbour during the Roman period.
La partie centrale du littoral du golfe du Lion est caractérisée par de nombreuses lagunes qui résultent de l'interaction entre un processus de régularisation du trait de côte par migration de barrières littorales et d'un lent remplissage des zones situées en arrière des barrières par des apports continentaux et marins. Les analyses des dépôts tardi-holocènes avec une étude multi-traceurs à très haute résolution de deux carottes sédimentaires nous permettent de reconstruire l'évolution de ce système côtier. Deux unités sédimentaires holocènes sont identifiées recouvrant une formation pliocène carbonatée. L'unité inférieure est constituée de sables et de galets d'origine marine déposés vers 7800 B.P., durant les stades ultimes de la dernière remontée marine. Audessus, l'unité supérieure montre des dépôts d'argile et de silt gris coquilliers d'origine lagunaire, dans lesquels sont intercalés des niveaux de sable silteux révélant la présence d'événements de tempêtes. Le modèle d'âge est établi à partir de dates radiocarbones pour les parties les plus anciennes des archives sédimentaires, tandis que pour le dernier siècle, les taux de sédimentation sont calculés en utilisant le modèle CFCS pour le 210Pb, associé aux données de 137Cs. Les données 14C montrent une augmentation du taux d'accumulation depuis la base jusqu'en surface des carottes. Les unités de sables marins liées aux dépôts de la dernière transgression marine permettent de préciser la courbe post-glaciaire de remontée du niveau marin. Les analyses sédimentologiques et faunistiques associées aux données chronologiques fournissent une méthode permettant de reconstituer les paléoenvironnements littoraux tardi-holocènes dans la zone d'étude et suggèrent que la fermeture finale de ces lagunes par le cordon sableux survient autour de 730 ± 120 ans cal B.P. Le début de cette fermeture, associée à la une progradation deltaïque, pourrait être responsable du déclin des activités économiques du port de Lattara durant la période Romaine.
EISSN: 1777-5817

halshs-00740923
https://halshs.archives-ouvertes.fr/halshs-00740923
DOI : 10.2113/gssgfbull.181.1.27

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BACKGROUND: The TGF-β transforming growth factor is the most pleiotropic cytokine controlling a broad range of cellular responses that include proliferation, differentiation and apoptosis. The context-dependent multifunctional nature of TGF-β is associated with complex signaling pathways. Differential models describe the dynamics of the TGF-β canonical pathway, but modeling the non-canonical networks constitutes a major challenge. Here, we propose a qualitative approach to explore all TGF-β-dependent signaling pathways. RESULTS: Using a new formalism, CADBIOM, which is based on guarded transitions and includes temporal parameters, we have built the first discrete model of TGF-β signaling networks by automatically integrating the 137 human signaling maps from the Pathway Interaction Database into a single unified dynamic model. Temporal property-checking analyses of 15934 trajectories that regulate 145 TGF-β target genes reveal the association of specific pathways with distinct biological processes. We identify 31 different combinations of TGF-β with other extracellular stimuli involved in non-canonical TGF-β pathways that regulate specific gene networks. Extensive analysis of gene expression data further demonstrates that genes sharing CADBIOM trajectories tend to be co-regulated. CONCLUSIONS: As applied here to TGF-β signaling, CADBIOM allows, for the first time, a full integration of highly complex signaling pathways into dynamic models that permit to explore cell responses to complex microenvironment stimuli.
ISSN: 1752-0509

inserm-00978313
http://www.hal.inserm.fr/inserm-00978313
http://www.hal.inserm.fr/inserm-00978313/document
http://www.hal.inserm.fr/inserm-00978313/file/1752-0509-8-30.pdf
DOI : 10.1186/1752-0509-8-30

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
OBJECTIVES: Tracheobronchial stenosis (TBS) is noted in 12-23% of patients with granulomatosis with polyangiitis (GPA), and includes subglottic stenosis and bronchial stenosis. We aimed to analyse the endoscopic management of TBS in GPA and to identify factors associated with the efficacy of endoscopic interventions. METHODS: We conducted a French nationwide retrospective study that included 47 patients with GPA-related TBS. RESULTS: Compared with patients without TBS, those with TBS were younger, more frequently female and had less frequent kidney, ocular and gastrointestinal involvement and mononeuritis multiplex. Endoscopic procedures included 137 tracheal and 50 bronchial interventions, mainly endoscopic dilatation, local steroid injection and conservative laser surgery, and less frequently stenting. After the first endoscopic procedure, the cumulative incidence of endoscopic treatment failure was 49% at 1 year, 70% at 2 years and 80% at 5 years. Factors significantly associated with a higher cumulative incidence of treatment failure were a shorter time from GPA diagnosis to endoscopic procedure [hazard ratio (HR) 1.08 (95% CI 1.01, 1.14); P = 0.01] and a bronchial stenosis [HR 1.96 (95% CI 1.28, 3.00); P = 0.002]. A prednisone dose ≥30 mg/day at the time of the procedure was associated with a lower cumulative incidence of treatment failure [HR 0.53 (95% CI 0.31, 0.89); P = 0.02]. CONCLUSION: TBS represents severe and refractory manifestations with a high rate of restenosis. High-dose systemic CSs at the time of the procedure and increased time from GPA diagnosis to bronchoscopic intervention are associated with a better event-free survival. In contrast, bronchial stenoses are associated with a higher rate of restenosis than subglottic stenosis.
ISSN: 1462-0324

hal-01155105
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01155105
DOI : 10.1093/rheumatology/kev129
PUBMED : 26001634