1,869 research outputs found
Theoretical photodetachment cross section for the negative atomic oxygen ion
Theoretical photodetachment cross section for negative atomic oxygen io
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Update of Atlas of Major Texas Oil Reservoirs Data Base and Atlas of Major Texas Gas Reservoirs Data Base
Updating both the "Atlas of Major Texas Oil Reservoirs: Database" (Holtz and others, 1991) and the "Atlas of Major Texas Gas Reservoirs: Database" (Garrett and others, 1991) centered on updating cumulative production data current to December 31, 1992, for reservoirs already in the database and adding new significant-sized reservoirs (cumulative production greater than 1 million barrels of oil equivalent) to the databases. Addition of new reservoirs to the database resulted in the modification of existing plays or the determination of new plays. Play boundaries were also modified to accommodate the additional reservoirs. Oil and gas production data used for the cumulative production update and the determination of significant-sized reservoirs were obtained from Dwight's Energy data. For reservoirs already included in the Atlas databases, annual production values were added to the cumulative production already determined by the Bureau of Economic Geology (BEG) or reported by the Railroad Commission of Texas. For new reservoirs, the cumulative production values reported by Dwight's Energy data were applied. Oil reservoirs originally listed in both databases because of large gas production were combined and now are listed only in the updated Oil Atlas database.Bureau of Economic Geolog
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Geologic Anaylsis of Primary and Secondary Tight Gas Sand Objectives Phase A&B
Finley (1982) listed geologic and engineering characteristics of over 30 blanket-geometry tight gas sandstones in a survey of 16 sedimentary basins. Emphasis was placed on defining elastic depositional systems and on using constituent facies as a method of evaluating the common features of stratigraphic units of different ages in diverse sedimentary and structural settings. Blanket-geometry tight gas sandstones considered suitable for future research by the Gas Research Institute were found to occur primarily within deltaic and barrier-strandplain depositional systems. An assessment of expected transferability of research results (extrapolation potential) was made between stratigraphic units, and more detailed study of six formations was recommended.
The Corcoran and Cozzette Sandstones of the Piceance Creek Basin and the Travis Peak Formation of the East Texas Basin and North Louisiana Salt Basin were recommended for research by the Gas Research Institute on blanket-geometry tight gas sandstones, and initial studies of depositional systems were begun. The Corcoran and Cozzette represent the barrier-strandplain system and contain barrier, offshore bar, and associated marginal-marine facies. Detailed studies of the Corcoran-Cozzette in Shire Gulch and Plateau Fields show shoreface sequences common to the lower parts of both units, and bay-lagoon and deltaic facies occur in the upper parts. The Travis Peak Formation represents a deltaic system, having a lower subdivision of progradational deltaic facies, a thick middle subdivision of braided alluvial deposits, and an upper subdivision of marginal marine deposits influenced by marine transgression. Sands greater than 50 ft thick are prominent in the middle subdivision in areas on the west flank of the Sabine Uplift. The Frontier Formation and the upper Almond Formation of the Greater Green River Basin and the Olmos Formation of the Maverick Basin are not recommended for further research, but should be considered when the need arises to test barrier, offshore bar, and possibly deltaic facies outside the two main research areas. The estimated gas resources associated with the Corcoran-Cozzette and the Travis Peak in Texas are 3.7 and 17.3 Tcf respectively. The Mancos "B" of the Piceance Creek Basin is not recommended for any additional research because its unique distribution of lithologies limits its extrapolation to a small group of shelf deposits, some of which have already been investigated. The extrapolation potential of the Travis Peak is largely to itself over a wide area of East Texas and North Louisiana. Extrapolation potential of the Corcoran and Cozzette extends to a large number of stratigraphic units, mostly within the Upper Cretaceous of the Rocky Mountain Region.Bureau of Economic Geolog
Bulk Charging of Dielectrics in Cryogenic Space Environments
We use a 1-D bulk charging model to evaluate dielectric charging at cryogenic temperatures relevant to space systems using passive cooling to <100K or extended operations in permanently dark lunar craters and the lunar night
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Opportunities for Additional Recovery in University Lands Reservoirs -- Characterization of University Lands Reservoirs, Final Report
In 1984, The University of Texas System funded a Bureau of Economic Geology project, "Characterization of University Lands Reservoirs," to assess in detail the potential for incremental recovery of oil from University Lands reservoirs by extended conventional methods. The objectives of the 5-year project were to quantify the volumes of unrecovered mobile oil remaining in reservoirs on University Lands, to determine whether the specific location of the unrecovered mobile oil could be delineated through integrated geoscience characterization of individual reservoirs, and to develop strategies to optimize recovery of this resource. Unrecovered mobile oil is mobile at reservoir conditions but is prevented from migrating to the wellbore by geologic complexities or heterogeneities. This final report describes results of the 5 years of research conducted on University Lands reservoirs.
One hundred and one reservoirs, each of which has produced more than 1 million stock tank barrels (MMSTB) of oil, were included in a resource assessment and play analysis undertaken (1) to determine the volumes and distribution of all components of the University Lands resource base and (2) to select reservoirs for detailed analysis. These reservoirs collectively contained 7.25 billion barrels (BSTB) of oil at discovery, have produced 1.5 BSTB, and contain 200 MMSTB of reserves. Ultimate recovery at implemented technology is projected to be 24 percent of the original oil in place; thus, 5.5 BSTB of oil will remain after recovery of existing reserves. Unrecovered mobile oil (exclusive of reserves) amounts to 2.2 BSTB, and immobile, or residual, oil totals 3.3 BSTB.Bureau of Economic Geolog
Psychological interventions in asthma
Asthma is a multifactorial chronic respiratory disease characterised by recurrent episodes of airway obstruction. The current management of asthma focuses principally on pharmacological treatments, which have a strong evidence base underlying their use. However, in clinical practice, poor symptom control remains a common problem for patients with asthma. Living with asthma has been linked with psychological co-morbidity including anxiety, depression, panic attacks and behavioural factors such as poor adherence and suboptimal self-management. Psychological disorders have a higher-than-expected prevalence in patients with difficult-to-control asthma. As psychological considerations play an important role in the management of people with asthma, it is not surprising that many psychological therapies have been applied in the management of asthma. There are case reports which support their use as an adjunct to pharmacological therapy in selected individuals, and in some clinical trials, benefit is demonstrated, but the evidence is not consistent. When findings are quantitatively synthesised in meta-analyses, no firm conclusions are able to be drawn and no guidelines recommend psychological interventions. These inconsistencies in findings may in part be due to poor study design, the combining of results of studies using different interventions and the diversity of ways patient benefit is assessed. Despite this weak evidence base, the rationale for psychological therapies is plausible, and this therapeutic modality is appealing to both patients and their clinicians as an adjunct to conventional pharmacological treatments. What are urgently required are rigorous evaluations of psychological therapies in asthma, on a par to the quality of pharmaceutical trials. From this evidence base, we can then determine which interventions are beneficial for our patients with asthma management and more specifically which psychological therapy is best suited for each patient
The impact of low erythrocyte density in human blood on the fitness and energetic reserves of the African malaria vector Anopheles gambiae
Background
Anaemia is a common health problem in the developing world. This condition is characterized by a reduction in erythrocyte density, primarily from malnutrition and/or
infectious diseases such as malaria. As red blood cells are the primary source of protein for haematophagous mosquitoes, any reduction could impede the ability of mosquito vectors to transmit malaria by influencing their fitness or that of the parasites they transmit. The aim of this study was to determine the impact of differences in the density of red blood cells in human blood on malaria vector (Anopheles gambiae sensu stricto) fitness. The hypotheses tested are that mosquito vector energetic reserves and fitness are negatively influenced by reductions in the red cell density of host human blood meals commensurate with those expected from severe anaemia.
Methods
Mosquitoes (An. gambiae s.s.) were offered blood meals of different packed cell volume(PCV) of human blood consistent with those arising from severe anaemia (15%) and normalPCV (50%). Associations between mosquito energetic reserves (lipid, glucose and glycogen)and fitness measures (reproduction and survival) and blood meal PCV were investigated.
Results
The amount of protein that malaria vectors acquired from blood feeding (indexed by
haematin excretion) was significantly reduced at low blood PCV. However, mosquitoes
feeding on blood of low PCV had the same oviposition rates as those feeding on blood of normal PCV, and showed an increase in egg production of around 15%. The long-term survival of An. gambiae s.s was reduced after feeding on low PCV blood, but PCV had no significant impact on the proportion of mosquitoes surviving through the minimal period required to develop and transmit malaria parasites (estimated as 14 days post-blood feeding). The impact of blood PCV on the energetic reserves of mosquitoes was relatively minor.
Conclusions
These results suggest that feeding on human hosts whose PCV has been depleted due to severe anaemia does not significantly reduce the fitness or transmission potential of malaria vectors, and indicates that mosquitoes may be able exploit resources for reproduction more
efficiently from blood of low rather than normal PCV
Efimov effect in quantum magnets
Physics is said to be universal when it emerges regardless of the underlying
microscopic details. A prominent example is the Efimov effect, which predicts
the emergence of an infinite tower of three-body bound states obeying discrete
scale invariance when the particles interact resonantly. Because of its
universality and peculiarity, the Efimov effect has been the subject of
extensive research in chemical, atomic, nuclear and particle physics for
decades. Here we employ an anisotropic Heisenberg model to show that collective
excitations in quantum magnets (magnons) also exhibit the Efimov effect. We
locate anisotropy-induced two-magnon resonances, compute binding energies of
three magnons and find that they fit into the universal scaling law. We propose
several approaches to experimentally realize the Efimov effect in quantum
magnets, where the emergent Efimov states of magnons can be observed with
commonly used spectroscopic measurements. Our study thus opens up new avenues
for universal few-body physics in condensed matter systems.Comment: 7 pages, 5 figures; published versio
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