1,361 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

    Tuberculose extrapulmonar em pacientes com AIDS na cidade do Rio Grande, Brasil. Diagnóstico laboratorial

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    ABSTRACTOne hundred two specimens of extrapulmonary material from 74 AIDS patients from the AIDS Service of University Hospital, FURG, Rio Grande, RS, Brazil, were examined at Mycobacteria Laboratory, between September 1997 and December 1999. This study had the aim to evaluate laboratoy importance in the diagnosis of extrapulmonary tuberculosis in AIDS patients with clinical suggestive symptoms of tuberculosis. Acid-fast bacilli (AFB) stains were performed using the Kinyon Method (cold stainning). Mycobacterial isolation was made In the Ogawa medium. The Ogawa medium added with p-nitrobenzoic acid, 2-tiophenocarboxylic acid hidrazide and pyruvic acid sodium salt was used to the Identification of mycobacterial species. Confirmation of Mycobacterium tuberculosis was done by the niacin test. The extrapulmonary tuberculosis diagnosis was done in 12,74% of specimens from 17,56% of the patients. Distribution of specimens with positive results in relation to the obtained sites were: 8/13 lymph node biopsies, 2/13 liver biopsies, 2/13 ascitic nuid and 1/13 pleural nuid. ABF were found on microscopic examination from 7/13 specimens and 10/13 in culture. The microscopic examination of ABF stain was the only method responsible for the extrapulmonary tuberculosis diagnostic in 3/13 cases and the culture in 6/13 cases. Among the positive specimens at microscopic examination or ABF stains, 6/7 were lymph node biopsies and In ascitic fluid. The used methods in the diagnosis, of the extrapulmonary tuberculosis showed good results, by this way we strongly recommend the realization of both as routine in our place.REV PORT PNEUMOL 2000; VI (4): 277-28
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