The continental margin off Oregon from seismic investigations

In April and May 1996, a geophysical study of the Cascadia continental margin off Oregon and Washington was carried out aboard the German RV Sonne as a cooperative experiment between GEOMAR, the USGS and COAS. Offshore central Oregon, which is the subject of this study, the experiment involved the collection of wide-angle refraction and reflection data along three profiles across the continental margin using ocean-bottom seismometers (OBS) and hydrophones (OBH) as well as land recorders. Two-dimensional modelling of the travel times provides a detailed velocity structure beneath these profiles. The subducting oceanic crust of the Juan de Fuca plate can be traced from the trench to its position some 10 km landward of the coastline. At the coastline, the Moho has a depth of 30 km. The dip of the plate changes from 1.5° westward of the trench to about 6.5° below the accretionary complex and to about 16° further eastward below the coast. The backstop forming western edge of the Siletz terrane, an oceanic plateau that was accreted to North America about 50 Ma ago, is well defined by the observations. It is located about 60 km to the east of the deformation front and has a seaward dip of 40°. At its seaward edge, the base of the Siletz terrane seems to be in contact with the subducting oceanic crust implying that sediments are unlikely to be subducted to greater depths. The upper oceanic crust is thinner to the east of this contact than to the west. At depths greater than 18 km, the top of the oceanic crust is the origin of pre-critical reflections observable in several land recordings and in the data of one ocean bottom instrument. These reflections are most likely caused by fluids that are released from the oceanic crust by metamorphic facies transition

[Profunda artery perforator flap: Reliable secondary option for breast reconstruction?]

In recent years, the DIEP-flap has become the standard for autologous breast reconstruction. However, when abdominal donor site is unavailable, secondary options are numerous. This report documents our experience with PAP-flap breast reconstruction. We carried out a retrospective study of patients who underwent reconstructive breast surgery by PAP-flaps in our institution since 2014. Seventeen PAP-flaps were carried out in 15 patients, two of which received consecutive reconstruction of each breast at distinct intervals. Indication was lack of abdominal excess in 8 patients and history of abdominoplasty in 6 patients. These six patients and one more had bad or absence of perforator for DIEP flap. There were 2 flap losses (11.8%). Other complications included minor dehiscences from seroma at donor site in 6 cases (35.3%), flap dehiscence in one case (5.8%), and receiver site hematoma in 1 patient (5.8%). The authors analyze their series when the high rate of complications and the results obtained compared to the second alternative choices of other teams. The author is of the opinion that the PAP-Flap is a reliable option as a second choice for breast reconstruction in patients whose DIEP can not be retained. It is limited in terms of volume and a third choice should be considered when the indication is to reconstruct a breast of large volume

La fistule palatine ou vélaire dans les fentes

International audienc

SO 103 - CONDOR 1B: a study of Chilean offshore natural disasters and ocean environmental research Final report

Near Valparaiso, Chile, a fundamental change in structure of the continental margin occurs opposite the subducting Juan Fernandez Ridge. Wideanle seismic profiles were collected in the two degree segment offshore Valparaiso, extending from the shelf edge seaward across the eastern end of Juan Fernandez-Ridge. Near the O'Higgins seamount, the Juan-Fernandez Ridge strikes north-east rather than continuing its east-west trend across the Pacific Basin. The subducting ridge uplifts the upper plate and its advancing southern flank deforms sediments of the Valparaiso forearc basin. This deformation is consistent with the southward migration required by an oblique trending ridge and the nearly trench-normal vector of plate convergence. In the trench axis, the ridge forms a basement barrier behind which sediments 2.5 km, deep have ponded. The lower slope over the ridge appears eroded, whereas the margin not yet affected by ridge subduction is fronted by an accretionary prism about 25 km wide. Nazca plate relief clearly influences tectonism of the margin where it subducts beneath thin continental crust but its relation to deeper processes segmenting the Andean Orogen appears to also involve prior tectonic events. Surprisingly no crustal thickening of the oceanic plate is found near Juan Fernandez Ridge. (orig.)Available from TIB Hannover: F99B17 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Structure of di[3,4;3',4'-bis(ethylenedithio)-2,2',5,5'-tetrathiafulvalenium]tetraiodogallate(III), (BEDT-TTF)2GaI4

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Split temporalis muscle flap anatomy, vascularization and clinical applications

Introduction : For more than a century, the temporalis muscle has been used for facial reconstructions. More recently, a split temporalis muscle flap elevated on the superficial temporal pedicle has been described, for which the resulting gain of length makes crossing of the midline possible, as well as reconstruction of substance losses exceeding the midline. Materials and methods : Fourteen fresh cadaveric dissections were performed to study the different techniques for splitting the temporalis muscle. Dissections with catheterization and injection of radio-opaque contrasting agent in the external carotid artery were then performed to specify the vascularization of the flap split on the superficial temporal pedicle. Results : The duplication of the superficial temporal pedicle grants greater length compared to that of the deep pedicles, 57 mm versus 40 (p = 0.036). The middle temporal artery is capable of ensuring the vascularization, and therefore the viability, of the split flap. From these results, we spoke about the limitations of this study and we have inferred the main indications

A marine electromagnetic survey to detect gas hydrate at Hydrate Ridge, Oregon

Gas hydrates are a potential energy resource and hazard for drilling and infrastructure, yet estimates of global volume vary by over three orders of magnitude. Hydrates are electrically resistive compared to water saturated sediment and so electromagnetic methods provide an additional tool to seismic surveys and drilling for determining hydrate saturations. A marine electromagnetic survey was carried out at Hydrate Ridge, Oregon, USA, with the aim of testing the use of controlled source electromagnetic (CSEM) and magnetotelluric (MT) methods to map gas hydrate and free gas below the gas hydrate stability zone. A 2-D CSEM inversion supports the scenario deduced from previous seismic and drilling results, which indicate two mechanisms of hydrate emplacement: a transport-dominated and reaction-dominated regime. A prominent resistive region of 2.5–4 ?m at a depth of about 130 mbsf, near the seismic bottom simulating reflector (BSR), suggests that 27 to 46 per cent of the bulk volume is filled with hydrate, depending on whether Archie's Law or the Hashin-Strikman bounds are used. This is representative of a reaction-dominated regime for hydrate emplacement, and where a significant low velocity zone exists based on a seismic tomography inversion, suggests large quantities of free gas below the BSR. Electrical resistivity logging while drilling (LWD) data show general agreement with the CSEM inversion model except for a CSEM-derived resistive region at seismic horizon A, known to transport free gas into the gas hydrate stability zone. Inversion of MT data collected simultaneously during the CSEM survey provides a complimentary low-resolution image of the shallow sediments and shows folding in the accretionary complex sediments similar to that imaged by a tomographic seismic velocity model