Constraining Coronal Heating: Employing Bayesian Analysis Techniques to Improve the Determination of Solar Atmospheric Plasma Parameters

One way of revealing the nature of the coronal heating mechanism is by comparing simple theoretical one dimensional hydrostatic loop models with observations at the temperature and/or density structure along these features. The most well-known method for dealing with comparisons like that is the $\chi^2$ approach. In this paper we consider the restrictions imposed by this approach and present an alternative way for making model comparisons using Bayesian statistics. In order to quantify our beliefs we use Bayes factors and information criteria such as AIC and BIC. Three simulated datasets are analyzed in order to validate the procedure and assess the effects of varying error bar size. Another two datasets (Ugarte-Urra et al., 2005; Priest et al., 2000) are re-analyzed using the method described above. In one of these two datasets (Ugarte-Urra et al., 2005), due to the error estimates in the observed temperature values, it is not posible to distinguish between the different heating mechanisms. For this we suggest that both Classical and Bayesian statistics should be applied in order to make safe assumptions about the nature of the coronal heating mechanisms

Plio-Pleistocene Depositional Sequences of the Southwestern Louisiana Continental Shelf and Slope: Geologic Framework, Sedimentary Facies and Hydrocarbon Distribution

The Plio-Pleistocene hydrocarbon fairway of offshore Louisiana is restricted to the outer continental shelf and upper continental slope where a thick wedge of nearshore and deep marine sediments was deposited. Electric logs, paleontological reports, and seismic profiles form the basis for (1) dividing the wedge of Plio-Pleistocene strata into eight genetic sequences, (2) establishing the structural framework, (3) determining the timing of deformation, and (4) mapping the principal depositional systems of the West Cameron and western Garden Banks areas during the past five million years. Sedimentary facies and structural styles in this part of the basin are highly variable owing to contemporaneous sea-level fluctuations, salt migration, and shifting sites of deltaic, shelf, and slope sedimentation. The resulting complex geologic history of this part of the basin directly controlled the generation, migration, and entrapment of hydrocarbons. The early Pliocene was a period of continental platform inundation and deposition of a thick succession of marine mudstones. About 3 Ma, this monotonous accumulation of deep-water mudstone was interrupted by deposition of sand-rich submarine channels and fans associated with a lowering of sea level. These lowstand deposits extended at least 55 mi (90 km) basinward of the paleomargin. Overlying Pleistocene sediments were deposited mainly by prograding mud-rich fluvial-deltaic systems of moderate size. These rivers and shelf-edge deltas constructed a broad continental platform that buried the submarine fans and prograded the shelf margin approximately 70 mi (110 km) basinward. During this rapid outbuilding, slumping and other gravity-driven mass transport processes removed sand-rich delta-front sediments from unstable shelf margins and redeposited them on the continental slope.Bureau of Economic Geolog

Plio-Pleistocene Depositional Sequences of the Southwestern Louisiana Continental Shelf and Slope: Geologic Framework, Sedimentary Facies and Hydrocarbon Distribution

The Plio-Pleistocene hydrocarbon fairway of offshore Louisiana is restricted to the outer continental shelf and upper continental slope where a thick wedge of nearshore and deep marine sediments was deposited. Electric logs, paleontological reports, and seismic profiles form the basis for (1) dividing the wedge of Plio-Pleistocene strata into eight genetic sequences, (2) establishing the structural framework, (3) determining the timing of deformation, and (4) mapping the principal depositional systems of the West Cameron and western Garden Banks areas during the past five million years. Sedimentary facies and structural styles in this part of the Gulf Coast basin are highly variable owing to contemporaneous sea-level fluctuations, salt migration, and shifting sites of deltaic, shelf, and slope sedimentation. The resulting complex geologic history of this part of the basin was interpreted to determine what controlled the generation, migration, and entrapment of hydrocarbons. The early Pliocene was a period of continental platform inundation and deposition of a thick succession of marine mudstones. About 3 million years ago, this monotonous accumulation of deep-water mudstone was interrupted by deposition of sand-rich submarine channels and fans associated with a lowering of sea level. These lowstand deposits extended at least 55 miles (90 km) basinward of the paleomargin. Overlying Pleistocene sediments were deposited mainly by prograding mud-rich fluvial-deltaic systems of moderate size. These rivers and shelf-edge deltas constructed a broad continental platform that buried the submarine fans and prograded the shelf margin approximately 70 miles (110 km) basinward. During this rapid outbuilding, slumping and other gravity-driven mass transport processes removed sand-rich delta-front sediments from unstable shelf margins and redeposited them on the continental slope.Bureau of Economic Geolog

Consolidation of Geologic Studies of Geopressured-Geothermal Resources in Texas

Detailed structural mapping at several horizons in selected study areas within the Frio growth-fault trend demonstrates a pronounced variability in structural style. At Sarita in South Texas, shale mobilization produced one or more shale ridges, one of which localized a low-angle growth fault trapping a wedge of deltaic sediments. At Corpus Christi, shale mobilization produced a series of large growth faults, shale-cored domed anticlines, and shale-withdrawal basins, which become progressively younger basinward. At Blessing, major growth faults trap sands of the Greta/Calhoun barrier system, having some discrete shale diapirs but little progradation. At Pleasant Bayou, a major early growth-fault system was overprinted by salt tectonics—the intrusion of Danbury Dome and the development of a salt-withdrawal basin. At Port Arthur, low-displacement, long-lived faults formed on a sand-poor shelf margin contemporaneously with broad salt uplifts and basins. Variability in styles can be related to the nature and extent of Frio sedimentation and shelf-margin progradation and to the presence of salt. Structural styles that are conducive to large geothermal reservoirs include blocks between widely spaced growth faults having dip reversal, salt-withdrawal basins, and shale-withdrawal basins. These styles are widespread on the Texas Gulf Coast. However, actually finding a large reservoir depends on demonstrating the existence of sufficient sand having adequate quality to support geopressured geothermal energy production.Bureau of Economic Geolog

Ultraviolet Imaging of the Globular Cluster 47 Tucanae

We have used the Ultraviolet Imaging Telescope to obtain deep far-UV (1620 Angstrom), 40' diameter images of the prototypical metal-rich globular cluster 47 Tucanae. We find a population of about 20 hot (Teff > 9000 K) objects near or above the predicted UV luminosity of the hot horizontal branch (HB) and lying within two half-light radii of the cluster center. We believe these are normal hot HB or post-HB objects rather than interacting binaries or blue stragglers. IUE spectra of two are consistent with post-HB phases. These observations, and recent HST photometry of two other metal-rich clusters, demonstrate that populations with rich, cool HB's can nonetheless produce hot HB and post-HB stars. The cluster center also contains an unusual diffuse far-UV source which is more extended than its V-band light. It is possible that this is associated with an intracluster medium, for which there was earlier infrared and X-ray evidence, and is produced by C IV emission or scattered light from grains.Comment: 13 pages AASLaTeX including one postscript figure and one bitmapped image, JPEG format. Submitted to the Astronomical Jorunal. Full Postscript version available at http://www.astro.virginia.edu/~bd4r

Mathematical simulations for better aquifer management

CER-66-67 MWB 10.Extract of publication no. 72 of the I.A.S.H. Symposium of Haifa.Includes bibliographical references.Manipulation of groundwater storage in conjunction with surface water supplies often requires simultaneous consideration of varied aquifer hydraulic and geometric characteristics, highly variable pumping patterns in time and space, imperfectly connected bodies of surface water and non-deterministic natural recharge. In addition, legal, economic and social conditions impose constraints which must be considered in aquifer operation and management. This paper describes mathematical modeling and computer analysis techniques that allow consideration of the many varied and changing factors mentioned above. Application is made to specific aquifer management problems

Experiments on Nucleation in Different Flow Regimes

The vast majority of metallic engineering materials are solidified from the liquid phase. Understanding the solidification process is essential to control microstructure, which in turn, determines the properties of materials. The genesis of solidification is nucleation, where the first stable solid forms from the liquid phase. Nucleation kinetics determine the degree of undercooling and phase selection. As such, it is important to understand nucleation phenomena in order to control solidification or glass formation in metals and alloys