904 research outputs found
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Report of Investigations No. 123 Petroleum Potential of the Palo Duro Basin, Texas Panhandle
UT Librarie
Suppressing low-order eigenmodes with local control for deformable mirrors
To improve the mechanical characteristics of actively controlled continuous faceplate deformable mirrors in adaptive optics, a strategy for reducing crosstalk between adjacent actuators and for suppressing low-order eigenmodes is proposed. The strategy can be seen as extending Saint-Venantâs principle beyond the static case, for small local families of actuators. An analytic model is presented, from which we show the feasibility of the local control. Also, we demonstrate how eigenmodes and eigenfrequencies are affected by mirror parameters, such as thickness, diameter, Youngâs modulus, Poissonâs ratio, and density. This analysis is used to evaluate the design strategy for a large deformable mirror, and how many actuators are needed within a family
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Effects of Stratal Architecture and Diagenesis on Reservoir Development in the Grayburg Formation: South Cowden Field, Ector County, Texas
The Grayburg Formation in the South Cowden field of eastern Ector County displays an internal stratal architecture that typifies Grayburg shallow-water platform successions throughout the Permian Basin. Study of core and wireline logs in South Cowden field documents three orders of cyclicity in the Grayburg. The entire Grayburg constitutes a single long-duration accommodation cycle that commenced with a major sea-level rise and flooding of the preexisting San Andres platform and ended with a major basinward shift in facies associated with sea-level fall prior to deposition of Queen Formation tidal-flat successions. Four high-frequency sequences are recognized within the Grayburg that correspond to higher frequency sea-level rise events. The basal Grayburg sequence consists of backstepping, low-energy, mud-dominated cycles and is not a contributor to production in the field. Grayburg sequence 2 documents extensive flooding of the San Andres platform by outer ramp fusulinid wackestone-packstone facies and subsequent aggradation of an extensive tidal-flat-capped, grain-dominated packstone-grainstone ramp crest succession. Renewed platform transgression in Grayburg sequence 3, demonstrated by even more extensive onlap of the platform by fusulinid facies, documents a maximum flooding event that is correlatable throughout the Grayburg in both outcrop and subsurface. This event forms the basis for correlation of the Grayburg succession throughout the Permian Basin. Grayburg sequence 4 reflects highstand reduction of platform-to-basin relief and a major basinward shift in facies tracts.Bureau of Economic Geolog
Die Proteine
Layoutgetreues Digitalisat der Ausg.: Marburg : Elwert, 1900
tandort: Fachgebiet fĂŒr Geschichte der Medizin (192)
Signatur: 793/IV
Provenienz: Behring, Emil vo
Longitude : a privacy-preserving location sharing protocol for mobile applications
Location sharing services are becoming increasingly popular. Although many location sharing services allow users to set up privacy policies to control who can access their location, the use made by service providers remains a source of concern. Ideally, location sharing providers and middleware should not be able to access usersâ location data without their consent. In this paper, we propose a new location sharing protocol called Longitude that eases privacy concerns by making it possible to share a userâs location data blindly and allowing the user to control who can access her location, when and to what degree of precision. The underlying cryptographic algorithms are designed for GPS-enabled mobile phones. We describe and evaluate our implementation for the Nexus One Android mobile phone
Intraplate strike-slip faulting in East Antarctica: new geophysical views from the Rennick Graben and Wilkes Subglacial Basin
Intraplate strike-slip faulting can occur in association with different geodynamic settings, ranging from subduction-related to collision and extension. Geological and geophysical research in Northern Victoria Land (NVL) in East Antarctica, has led to the interpretation that major fault systems that were active during the early Paleozoic Ross Orogen were reactivated much later as right-lateral intraplate strike-slip fault systems from ca 48 Ma, and that these faults may have accomodated differential shear along evolving oceanic transform faults located between southeastern Australia and Tasmania. One of the main structures in NVL that has been inferred to relate to this unusual geodynamic process is the Rennick Graben (RG), but its age, extent and kinematics have remained both poorly constrained and controversial. Even less well-understood are the potential tectonic linkages between the RG and the deep sub-basins that lie within the much broader Wilkes Subglacial Basin (WSB), in the hinterland of the Transantarctic Mountains.
Here, we present new interpretations of enhanced potential field images derived from aeromagnetic and airborne and land-gravity observations to help constrain the extent and architecture of the RG and the sub-basins within the WSB. We show that the RG is a composite pull-part basin that extends from the Oates Coast towards the margin of the Ross Sea Rift, part of the West Antarctic Rift System. We suggest that the more cratonic WSB region was also affected by extensional and transtensional processes, the latter potentially linked to an evolving and distributed left-lateral Paleogene(?) strike-slip plate boundary between East Antarctica and Australia
Mass fractionation of noble gases in synthetic methane hydrate : implications for naturally occurring gas hydrate dissociation
This paper is not subject to U.S. copyright. The definitive version was published in Chemical Geology 339 (2013): 242-250, doi:10.1016/j.chemgeo.2012.09.033.As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings may presently be dissociating and releasing methane and other gases to the oceanâatmosphere system. A key challenge in assessing the impact of dissociating gas hydrates on global atmospheric methane is the lack of a technique able to distinguish between methane recently released from gas hydrates and methane emitted from leaky thermogenic reservoirs, shallow sediments (some newly thawed), coal beds, and other sources. Carbon and deuterium stable isotopic fractionation during methane formation provides a first-order constraint on the processes (microbial or thermogenic) of methane generation. However, because gas hydrate formation and dissociation do not cause significant isotopic fractionation, a stable isotope-based hydrate-source determination is not possible. Here, we investigate patterns of mass-dependent noble gas fractionation within the gas hydrate lattice to fingerprint methane released from gas hydrates. Starting with synthetic gas hydrate formed under laboratory conditions, we document complex noble gas fractionation patterns in the gases liberated during dissociation and explore the effects of aging and storage (e.g., in liquid nitrogen), as well as sampling and preservation procedures. The laboratory results confirm a unique noble gas fractionation pattern for gas hydrates, one that shows promise in evaluating modern natural gas seeps for a signature associated with gas hydrate dissociation.Partial support for this research was provided by Interagency Agreements
DE-FE0002911 and DE-NT0006147 between the U.S. Geological
Survey Gas Hydrates Project and the U.S. Department of Energy's Methane
Hydrates Research and Development Program
Corrigendum to âInsights into methane dynamics from analysis of authigenic carbonates and chemosynthetic mussels at newly-discovered Atlantic Margin seepsâ [Earth Planet. Sci. Lett. 449 (2016) 332â344]
This paper is not subject to U.S. copyright. The definitive version was published in Earth and Planetary Science Letters 475 (2017): 268, doi:10.1016/j.epsl.2017.07.037
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SETD3 is an actin histidine methyltransferase that prevents primary dystocia.
For more than 50Â years, the methylation of mammalian actin at histidine 73 has been known to occur1. Despite the pervasiveness of His73 methylation, which we find is conserved in several model animals and plants, its function remains unclear and the enzyme that generates this modification is unknown. Here we identify SET domain protein 3 (SETD3) as the physiological actin His73 methyltransferase. Structural studies reveal that an extensive network of interactions clamps the actin peptide onto the surface of SETD3 to orient His73 correctly within the catalytic pocket and to facilitate methyl transfer. His73 methylation reduces the nucleotide-exchange rate on actin monomers and modestly accelerates the assembly of actin filaments. Mice that lack SETD3 show complete loss of actin His73 methylation in several tissues, and quantitative proteomics analysis shows that actin His73 methylation is the only detectable physiological substrate of SETD3. SETD3-deficient female mice have severely decreased litter sizes owing to primary maternal dystocia that is refractory to ecbolic induction agents. Furthermore, depletion of SETD3 impairs signal-induced contraction in primary human uterine smooth muscle cells. Together, our results identify a mammalian histidine methyltransferase and uncover a pivotal role for SETD3 and actin His73 methylation in the regulation of smooth muscle contractility. Our data also support the broader hypothesis that protein histidine methylation acts as a common regulatory mechanism
Parametrically-stimulated recovery of a microwave signal using standing spin-wave modes of a magnetic film
The phenomenon of storage and parametrically-stimulated recovery of a
microwave signal in a ferrite film has been studied both experimentally and
theoretically. The microwave signal is stored in the form of standing spin-wave
modes existing in the film due to its finite thickness. Signal recovery is
performed by means of frequency-selective amplification of one of these
standing modes by double- requency parametric pumping process. The time of
recovery, as well as the duration and magnitude of the recovered signal, depend
on the timing and amplitudes of both the input and pumping pulses. A mean-field
theory of the recovery process based on the competitive interaction of the
signal-induced standing spin-wave mode and thermal magnons with the parametric
pumping field is developed and compared to the experimental data
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