The syn-rift sedimentary cover of the North Biscay Margin (bay of Biscay) : from new reflection seismic data

Le Bassin armoricain est un bassin sédimentaire profond situé au nord du golfe de Gascogne. Faute de données suffisantes, l’âge du bassin et son appartenance au domaine océanique ou à la marge armoricaine ont fait l’objet de nombreuses spéculations. Cette nouvelle étude sismo-stratigraphique, fondée sur une couverture dense de sismique réflexion, montre que la sédimentation dans le Bassin armoricain débute à l’Aptien, contemporaine de la dernière phase tectonique du rifting de la marge. La première formation sédimentaire de ce bassin, identifiée sous le nom de « couche 3B » et caractérisée par un faciès sismique chaotique et transparent, se serait mise en place par glissement dans la phase terminale du rifting lors de l’effondrement final de la marge, juste avant le début de l’ouverture océanique. Les nouvelles données de sismique réflexion apportent aussi des informations sur l’évolution polyphasée de la marge pendant son rifting. Deux événements se sont produits au Crétacé inférieur, l’un anté-Berriasien, l’autre Aptien, séparés par une période de calme entre le Berriasien supérieur et l’Aptien inférieur. Le premier événement est responsable de la structurationde la marge enblocs crustaux, le second de sonef fondrement et de la mise enplace des sédiments allochtones dans le Bassin armoricain

Fourier transform spectroscopy in the vibrational fingerprint region with a birefringent interferometer

We introduce a birefringent interferometer for Fourier transform (FT) spectroscopy in the mid-infrared, covering the vibrational fingerprint region (5-10 μm, 1000-2000 cm-1), which is crucial for molecular identification. Our interferometer employs the crystal calomel (Hg2Cl2), which combines high birefringence (ne-no≈0.55) with a broad transparency range (0.38-20 μm). We adopt a design based on birefringent wedges, which is simple and compact and guarantees excellent delay accuracy and long-term stability. We demonstrate FTIR spectroscopy, with a frequency resolution of 3 cm-1, as well as two-dimensional IR (2DIR) spectroscopy. Our setup can be extended to other spectroscopic modalities such as vibrational circular dichroism and step-scan FT spectroscopy

Contribution of bathymetry and geomorphology to the geodynamics of the East Indonesian seas

La compilation des données existantes et de celles recueillies dans le cadre de la coopération franco-indonésienne permet de présenter une nouvelle image bathymétrique des bassins océaniques de l’Est indonésien. La morphologie sert aussi de base aux études structurales menées à partir des données géophysiques insuffisamment denses. 3 bassins océaniques se sont ouverts successivement du NW au SE : le bassin Nord Banda (Sula) en position arrière arc, le bassin Sud Banda (Wetar et Damar) qui s’est ouvert au sein de l’arc volcanique et le bassin de Weber en position d’avant arc. La morphologie permet de préciser la direction d’ouverture NW-SE de ces bassins, en particulier dans le bassin de Sula où des accidents de cette direction, comme la zone de fracture de Tampomas sont mis en évidence. La carte bathymétrique permet aussi d’avancer des hypothèses sur la signification des rides de Banda qui séparent les bassins nord et sud. La succession d’ouverture de bassins est liée à la subduction australienne et à son recul. Le trait majeur de ces bassins est leur grande profondeur en regard de leur âge récent, qui ne s’intègre pas dans les modèles de subsidence thermique établis pour les grands océans ou pour les bassins marginaux. La situation géodynamique exceptionnelle qui place ces bassins au-dessus de plusieurs panneaux froids subductés et dans une région de collision active joue vraisemblablement un rôle important

“Topological Significance” Analysis of Gene Expression and Proteomic Profiles from Prostate Cancer Cells Reveals Key Mechanisms of Androgen Response

The problem of prostate cancer progression to androgen independence has been extensively studied. Several studies systematically analyzed gene expression profiles in the context of biological networks and pathways, uncovering novel aspects of prostate cancer. Despite significant research efforts, the mechanisms underlying tumor progression are poorly understood. We applied a novel approach to reconstruct system-wide molecular events following stimulation of LNCaP prostate cancer cells with synthetic androgen and to identify potential mechanisms of androgen-independent progression of prostate cancer.We have performed concurrent measurements of gene expression and protein levels following the treatment using microarrays and iTRAQ proteomics. Sets of up-regulated genes and proteins were analyzed using our novel concept of "topological significance". This method combines high-throughput molecular data with the global network of protein interactions to identify nodes which occupy significant network positions with respect to differentially expressed genes or proteins. Our analysis identified the network of growth factor regulation of cell cycle as the main response module for androgen treatment in LNCap cells. We show that the majority of signaling nodes in this network occupy significant positions with respect to the observed gene expression and proteomic profiles elicited by androgen stimulus. Our results further indicate that growth factor signaling probably represents a "second phase" response, not directly dependent on the initial androgen stimulus.We conclude that in prostate cancer cells the proliferative signals are likely to be transmitted from multiple growth factor receptors by a multitude of signaling pathways converging on several key regulators of cell proliferation such as c-Myc, Cyclin D and CREB1. Moreover, these pathways are not isolated but constitute an interconnected network module containing many alternative routes from inputs to outputs. If the whole network is involved, a precisely formulated combination therapy may be required to fight the tumor growth effectively

The anti-bacterial iron-restriction defence mechanisms of egg white; the potential role of three lipocalin-like proteins in resistance against Salmonella

Salmonella enterica serovar Enteritidis (SE) is the most frequently-detected Salmonella in foodborne outbreaks in the European Union. Among such outbreaks, egg and egg products were identified as the most common vehicles of infection. Possibly, the major antibacterial property of egg white is iron restriction, which results from the presence of the iron-binding protein, ovotransferrin. To circumvent iron restriction, SE synthesise catecholate siderophores (i.e. enterobactin and salmochelin) that can chelate iron from host iron-binding proteins. Here, we highlight the role of lipocalin-like proteins found in egg white that could enhance egg-white iron restriction through sequestration of certain siderophores, including enterobactin. Indeed, it is now apparent that the egg-white lipocalin, Ex-FABP, can inhibit bacterial growth via its siderophore-binding capacity in vitro. However, it remains unclear whether ex-FABP performs such a function in egg white or during bird infection. Regarding the two other lipocalins of egg white (Cal-γ and α-1-glycoprotein), there is currently no evidence to indicate that they sequester siderophores

The Seram ophiolites complexe (Central Indonesia: geochemical evidences for Early Miocene arc-splitting)

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Magnetic lineations constraints for the back-arc opening of the Late Neogene South Banda Basin (eastern Indonesia)

International audienceThe South Banda Basin is located within eastern Indonesia near the triple junction between the Eurasian, Pacific and Indo-Australian plates. It is underlain by oceanic crust, but its origin and age were not well established. It has been interpreted as a Mesozoic trapped piece of Indian ocean or as a Cretaceous-Eocene basin related to the Celebes and Sulu basins, but a Neogene back-arc origin was also considered. Recent geochemical and geochronological studies strongly support the latter hypothesis. In this paper we present a new analysis of the magnetic data from the eastern part of the South Banda Basin, the Damar Basin. We used magnetic field measurements collected during nine oceanographic cruises from various institutions. Looking for magnetic correlation in the time span given from recent geochronological data, the comparison between measured profiles and theoretical profiles deduced from the reversals of Earth's magnetic field during Neogene time allows us to infer an opening of South Banda Basin during Late Miocene-Early Pliocene time, from 6.5 to 3.5 Ma. Magnetic lineations 2An, 2Ar, 3n, 3r, 3An and possibly 3Ar are recognized, with an extinct spreading centre trending ENE-WSW. At least five segments are identified, each segment being separated by inactive transform faults perpendicular to the extinct spreading centre. A half spreading rate of about 3 cm/yr is calculated, based on spacing of magnetic lineations.The opening history of the basin is discussed. The cause of cessation of spreading is likely the arc-continent collision dated at about 3 Ma. However the onset of opening is less determined. We suggest that Damar Basin began to open at about 6.5 Ma during magnetic period 3An as an intra-arc basin, separating the Banda volcanic arc to the south from the incipient Lucipara volcanic arc to the north. The latter was probably created at the beginning of rifting of Damar Basin, as shown by both magnetic and geochronological data.The young age of the South Banda Sea Basin is contradictory with its great depth. We discuss this problem in view of thermal and tectonic considerations. We finally conclude that our magnetic model allows us to more precisely describe the opening of the basin

Axial incision: The key to understand submarine canyon evolution (in the western Gulf of Lion)

A detailed morphological analysis of the outer shelf and continental slope of the Western Gulf of Lion is presented, based on swath bathymetry data together with sub-bottom profiles and high resolution seismic reflection profiles. These data reveal two main erosive features, of very different dimensions: the axial incision and the canyon's major valley. The height of axial incisions' flanks with respect to the canyon deepest point (the thalweg) ranges from 40 to 150 m. It creates a small axial erosive path within the canyon's major valley, which is typically bounded by flanks of more than 700 m in height. We interpret the axial incision observed in the sea floor as the imprint of turbidity currents that eroded the floor of canyons during phases of connection to rivers (hyperpycnal turbidity current). Such currents are most likely to have formed during the Last Glacial Maximum (LGM) as both proximity of the shoreline (due to the lowstand of sea level) and high detrital sediment supply (due to glacial abrasion upstream) increased the flow of sediments delivered to the canyon heads. Fossil axial incisions, observed in seismic lines, are related to equivalent conditions. The axial incision, however, has a key influence on canyon evolution as it triggers mass wasting of different sizes that affect the canyon's major valley (head and flanks). We interpret the geometry of the canyon's major valley as the result of recurrent activity of axial incisions. These periods of activity occurred during low sea levels at glacial maxima and show a cyclicity of 100,000 years for the last 400,000 years