1,367 research outputs found

    Crestal fault geometries reveal late halokinesis and collapse of the Samson Dome, Northern Norway: Implications for petroleum systems in the Barents Sea

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    This paper uses 2D and high-quality 3D seismic reflection data to assess the geometry and kinematics of the Samson Dome, offshore Norway, revising the implications of the new data to hydrocarbon exploration in the Barents Sea. The study area was divided into three (3) zones in terms of fault geometries and predominant strikes. Displacement-length (D-x) and Throw-depth (T-z) plots showed faults to consist of several segments that were later dip-linked. Interpreted faults were categorised into three families, with Type A comprising crestal faults, Type B representing large E-W faults, and Type C consisting of polygonal faults. The Samson Dome was formed in three major stages: a) a first stage recording buckling of the post-salt overburden and generation of radial faults; b) a second stage involving dissolution and collapse of the dome, causing subsidence of the overburden and linkage of initially isolated fault segments; and c) a final stage in which large fault segments were developed. Late Cretaceous faults strike predominantly to the NW, whereas NE-trending faults comprise Triassic structures that were reactivated in a later stage. Our work provides scarce evidence for the escape of hydrocarbons in the Samson Dome. In addition, fault analyses based on present-day stress distributions indicate a tendency for ‘locking’ of faults at depth, with the largest leakage factors occurring close to the surface. The Samson Dome is an analogue to salt structures in the Barents Sea where oil and gas exploration has occurred with varied degrees of success

    Analysis of Binding Site Hot Spots on the Surface of Ras GTPase

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    We have recently discovered an allosteric switch in Ras, bringing an additional level of complexity to this GTPase whose mutants are involved in nearly 30% of cancers. Upon activation of the allosteric switch, there is a shift in helix 3/loop 7 associated with a disorder to order transition in the active site. Here, we use a combination of multiple solvent crystal structures and computational solvent mapping (FTMap) to determine binding site hot spots in the “off” and “on” allosteric states of the GTP-bound form of H-Ras. Thirteen sites are revealed, expanding possible target sites for ligand binding well beyond the active site. Comparison of FTMaps for the H and K isoforms reveals essentially identical hot spots. Furthermore, using NMR measurements of spin relaxation, we determined that K-Ras exhibits global conformational dynamics very similar to those we previously reported for H-Ras. We thus hypothesize that the global conformational rearrangement serves as a mechanism for allosteric coupling between the effector interface and remote hot spots in all Ras isoforms. At least with respect to the binding sites involving the G domain, H-Ras is an excellent model for K-Ras and probably N-Ras as well. Ras has so far been elusive as a target for drug design. The present work identifies various unexplored hot spots throughout the entire surface of Ras, extending the focus from the disordered active site to well-ordered locations that should be easier to target

    Delimitação e caracterização preliminar da Área de Proteção Ambiental do Camanducaia (SP/MG).

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    Este trabalho apresenta uma contribuição do geoprocessamento para a implantação da Área de Proteção Ambiental do Camanducaia (SP/MG). Através da combinação de técnicas de sensoriamento remoto, sistemas de informações geográficas e reconhecimentos em campo, foram produzidas informações georreferenciadas sobre a área e operacionalizada uma base cartográfica digital atualizada. Os resultados incluem a delimitação e descrição detalhada dos limites da APA e 10 mapas, na escala 1:250.000, sobre os principais componentes da paisagem da área

    Strategies for achieving sustainable logging rate in the Brazilian Amazon Forest.

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    Data of increment of the remnant trees after logging, ingrowth and mortality was obtained by assessment before logging and after 6 years, two sites of 50 ha, in Amazon forest. Logging scenarios were simulated to identify the logging rate potential for each studying sites, by diameter class projection method. The cy- cle of 35 years and the logging rate of 30 m3?ha?1 exceed the time required for recovery in the primary forest, in the studied site. The simulation showed that in the studying area, a well-planned logging, with minimum logging damage would be possible to implement an initial cycle of 25 years to the forest to re- cover 30 m3?ha?1, if 50% of the timber stock were reserved. The forest increment, beyond important fac- tors such as the increase of individual species, is quite dependent on the remnant trees

    Automatic workflow for narrow-band laryngeal video stitching

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    In narrow band (NB) laryngeal endoscopy, the clinician usually positions the endoscope near the tissue for a correct inspection of possible vascular pattern alterations, indicative of laryngeal malignancies. The video is usually reviewed many times to refine the diagnosis, resulting in loss of time since the salient frames of the video are mixed with blurred, noisy, and redundant frames caused by the endoscope movements. The aim of this work is to provide to the clinician a unique larynx panorama, obtained through an automatic frame selection strategy to discard non-informative frames. Anisotropic diffusion filtering was exploited to lower the noise level while encouraging the selection of meaningful image features, and a feature-based stitching approach was carried out to generate the panorama. The frame selection strategy, tested on on six pathological NB endoscopic videos, was compared with standard strategies, as uniform and random sampling, showing higher performance of the subsequent stitching procedure, both visually, in terms of vascular structure preservation, and numerically, through a blur estimation metric
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