462 research outputs found
Direct and Indirect Effects of Flood Basalt Volcanism on Reservoir Quality Sandstone
This thesis describes the direct diagenetic effects on porous clean sand substrate due to the emplacement of basalt lava flows. The thesis also describes the effects of the emplacement of basaltic dykes and sills into clean porous sandstone. The primary dataset comes from the Cretaceous Etendeka Group, NW Namibia, where the Etendeka Flood Basalts (and associated subsurface plumbing system) interacted with the aeolian Twyfelfontein Formation sandstone. Secondary datasets from the recent Rekjanes Peninsular basalts, Iceland; the Miocene Columbia River Flood Basalt province and the Miocene Snake River Basalts, NW USA are used to constrain the direct effects of lava on substrates in a variety of palaeoenvironmental conditions.
The thesis makes use of a number of analytical techniques including: petrography, scanning electron microscopy, image analysis, X-ray diffraction, X-Ray fluorescence, stable isotope spectroscopy (δ18 O and δ13 C) and gas permeability (Hasler and probe).
The findings of this work constrain the degree of porosity reduction in clean sandstones due to intrusion emplacement over a complete range of thermal regimes, controlled by the magma flow pathways and duration. The effects range from mild hydrothermal activity and compaction through to intense pyrometamorphism, sediment melting and segregation. Beneath lava flows, the degree of porosity loss is determined by palaeoenvironment (specifically the availability of free water), the lava thickness and the substrate composition. Together the geometries of the igneous components (intrusions and extrusive flows) of the Etendeka Group compartmentalise the sedimentary components (Twyfelfontein Formation), which can be traced due to their effects on hydrothermal activity. The main compartment forming lithologies are vertical-subvertical intrusions, with the lava flows being a minor contributor. The diagenesis during hydrothermal activity was found to be a natural sequestration mechanism of CO2 derived from igneous activity as well as a highly compartmentalised porosity degradation mechanism
Modeling petroleum expulsion in sedimentary basins : The importance of igneous intrusion timing and basement composition
We thank Siccar Point Energy Ltd. for permission to publish this study. Thanks also to Robert Holdsworth, Simon Holford and Christian Huag Eide for their insightful feedback which has greatly improved the manuscript. 1GSA Data Repository item 2019328, supplementary data (geochemical summary, rationale and data tables), is available online at http://www.geosociety.org/datarepository/2019/, or on request from [email protected] reviewedPublisher PD
Overthickening of sedimentary sequences by igneous intrusions
This study was part of a collaboration between the University of Aberdeen, Siccar Point Energy Ltd and Integrated Geochemical Interpretation (IGI). Siccar Point Energy Ltd are thanked for giving the author permission to publish. Karolina Harvie and Kevin Ward from Petrosys are thanks for their support during the mapping process of the project. The lead author’s PhD is funded by JX Nippon Exploration and Production (U.K.) Limited as part of the Volcanic Margin Research Consortium Phase 2. PGS are thanked for allowing the author access to the MegaSurveyPlus and PGS/TGS FSB 2011-12 MultiClient GeoStreamer data and for granting permission to publish this work. Seismic interpretation was carried out using Schlumberger Petrel software. Well log analysis was carried out using Schlumberger Techlog software. Dave Ellis and Victoria Pease are thanked for the comments which greatly improved the revisions of this paper. Well data was obtained from the UK Oil and Gas Authority (OGA) Common Data Access (CDA).Peer reviewedPostprin
Prospectus, February 13, 1973
COPHER, LOOKINGBILL SARP WINNERS; New campus organization to form; Access new WPGU show; SIU rep here; \u27Tar\u27 speaker at PC; PC Vets\u27 blood drive; Engineering invite at UI; The world\u27s great religions; Debate team meets DuPage; Let it not be said…; Commentary on Johnson and Nixon; Calsonis; Movie Review: The Poseidon Adventure ; Speaking of Sports; Ag students have \u27no job hassles\u27; Black schools have great opportunity; Discovering oneself through SRLhttps://spark.parkland.edu/prospectus_1973/1012/thumbnail.jp
The Oriented Scintillation Spectrometer Experiment - Instrument Description
The Oriented Scintillation Spectrometer Experiment on the Arthur Holly Compton Gamma Ray Observatory satellite uses four actively shielded NaI (Tl)-CsI(Na) phoswich detectors to provide gamma-ray line and continuum detection capability in the 0.05-10 MeV energy range. The instrument includes secondary capabilities for gamma-ray and neutron detection between 10 and 250 MeV. The detectors have 3.8 deg x 11.04 deg (FWHM) fields of view defined by tungsten collimators. Each detector has an independent, single-axis orientation system which permits offset pointing from the spacecraft Z-axis for background measurements and multitarget observations. The instrument, and its calibration and performance, are described
Nutraceutical Approach for Preventing Obesity-Related Colorectal and Liver Carcinogenesis
Obesity and its related metabolic abnormalities, including insulin resistance, alterations in the insulin-like growth factor-1 (IGF-1)/IGF-1 receptor (IGF-1R) axis, and the state of chronic inflammation, increase the risk of colorectal cancer (CRC) and hepatocellular carcinoma (HCC). However, these findings also indicate that the metabolic disorders caused by obesity might be effective targets to prevent the development of CRC and HCC in obese individuals. Green tea catechins (GTCs) possess anticancer and chemopreventive properties against cancer in various organs, including the colorectum and liver. GTCs have also been known to exert anti-obesity, antidiabetic, and anti-inflammatory effects, indicating that GTCs might be useful for the prevention of obesity-associated colorectal and liver carcinogenesis. Further, branched-chain amino acids (BCAA), which improve protein malnutrition and prevent progressive hepatic failure in patients with chronic liver diseases, might be also effective for the suppression of obesity-related carcinogenesis because oral supplementation with BCAA reduces the risk of HCC in obese cirrhotic patients. BCAA shows these beneficial effects because they can improve insulin resistance. Here, we review the detailed relationship between metabolic abnormalities and the development of CRC and HCC. We also review evidence, especially that based on our basic and clinical research using GTCs and BCAA, which indicates that targeting metabolic abnormalities by either pharmaceutical or nutritional intervention may be an effective strategy to prevent the development of CRC and HCC in obese individuals
Tropomyosin - master regulator of actin filament function in the cytoskeleton.
Tropomyosin (Tpm) isoforms are the master regulators of the functions of individual actin filaments in fungi and metazoans. Tpms are coiled-coil parallel dimers that form a head-to-tail polymer along the length of actin filaments. Yeast only has two Tpm isoforms, whereas mammals have over 40. Each cytoskeletal actin filament contains a homopolymer of Tpm homodimers, resulting in a filament of uniform Tpm composition along its length. Evidence for this ‘master regulator’ role is based on four core sets of observation. First, spatially and functionally distinct actin filaments contain different Tpm isoforms, and recent data suggest that members of the formin family of actin filament nucleators can specify which Tpm isoform is added to the growing actin filament. Second, Tpms regulate whole-organism physiology in terms of morphogenesis, cell proliferation, vesicle trafficking, biomechanics, glucose metabolism and organ size in an isoform-specific manner. Third, Tpms achieve these functional outputs by regulating the interaction of actin filaments with myosin motors and actin-binding proteins in an isoform-specific manner. Last, the assembly of complex structures, such as stress fibers and podosomes involves the collaboration of multiple types of actin filament specified by their Tpm composition. This allows the cell to specify actin filament function in time and space by simply specifying their Tpm isoform composition
Contrasting perspectives of strategy making: applications in 'Hyper' environments
We revisit the original meaning of turbulence in the socioecological tradition of organization studies and outline a perspective on strategy making grounded in that tradition. This entails a contrast of the socioecological perspective with the more well-known neoclassical perspective on strategy, based on their core decision premises and their different understandings of environmental turbulence. We argue that while some mainstream strategy approaches have taken important strides toward addressing advanced turbulence, many others remain tethered to the neoclassical origins of the strategy discipline and are insufficiently responsive to the new landscape of strategy that now characterizes many industries. This new landscape is construed as the ‘hyper environment’, in which positive feedback processes and emergent field effects produce high volatility. We use two case illustrations from the US healthcare sector to examine how neoclassical and socioecological perspectives contribute to strategizing in hyper environments. Implications for strategic management theory and practice flow from this analysis
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