530 research outputs found

    Current Status of EEG Telephone Telemetry

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    journal articleBiomedical Informatic

    Routine Transmission of Elecetroencephalograms by Telephone from a Distant Community

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    journal articleBiomedical Informatic

    High-speed imaging and wavefront sensing with an infrared avalanche photodiode array

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    Infrared avalanche photodiode arrays represent a panacea for many branches of astronomy by enabling extremely low-noise, high-speed and even photon-counting measurements at near-infrared wavelengths. We recently demonstrated the use of an early engineering-grade infrared avalanche photodiode array that achieves a correlated double sampling read noise of 0.73 e- in the lab, and a total noise of 2.52 e- on sky, and supports simultaneous high-speed imaging and tip-tilt wavefront sensing with the Robo-AO visible-light laser adaptive optics system at the Palomar Observatory 1.5-m telescope. We report here on the improved image quality achieved simultaneously at visible and infrared wavelengths by using the array as part of an image stabilization control-loop with adaptive-optics sharpened guide stars. We also discuss a newly enabled survey of nearby late M-dwarf multiplicity as well as future uses of this technology in other adaptive optics and high-contrast imaging applications.Comment: Accepted to Astrophysical Journal. 8 pages, 3 figures and 1 tabl

    Second generation Robo-AO instruments and systems

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    The prototype Robo-AO system at the Palomar Observatory 1.5-m telescope is the world's first fully automated laser adaptive optics instrument. Scientific operations commenced in June 2012 and more than 12,000 observations have since been performed at the ~0.12" visible-light diffraction limit. Two new infrared cameras providing high-speed tip-tilt sensing and a 2' field-of-view will be integrated in 2014. In addition to a Robo-AO clone for the 2-m IGO and the natural guide star variant KAPAO at the 1-m Table Mountain telescope, a second generation of facility-class Robo-AO systems are in development for the 2.2-m University of Hawai'i and 3-m IRTF telescopes which will provide higher Strehl ratios, sharper imaging, ~0.07", and correction to {\lambda} = 400 nm.Comment: 11 pages, 4 figures, 3 table

    Cyclosporin A protects hepatocytes subjected to high Ca2+ and oxidative stress

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    AbstractHepatocytes incubated with 0.8 mM t-butylhydroperoxide are protected by cyclosporin A when the medium Ca2+ concentration is 10 mM, but not when it is 2.5 mM. The highest Ca2+ level is associated with an inhibition of t-butylhydroperoxide-dependent malondialdehyde accumulation and with mitochondrial Ca2+ loading within the cells. These findings are new evidence that t-butylhydroperoxide can kill cells by peroxidation-dependent and -independent mechanisms, and suggest that the mitochondrial permeability transition and the resultant de-energization are components of the peroxidation-independent mechanism. Cyclosporin A may have considerable utility for the protection of cells subjected to oxidative stress

    Relating Groundwater to Seasonal Wetlands in Southeastern Wisconsin, USA

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    Historically, drier types of wetlands have been difficult to characterize and are not well researched. Nonetheless, they are considered to reflect the precipitation history with little, if any, regard for possible relation to groundwater. Two seasonal coastal wetland types (wet prairie, sedge meadow) were investigated during three growing seasons at three sites in the Lake Michigan Basin, Wisconsin, USA. The six seasonal wetlands were characterized using standard soil and vegetation techniques and groundwater measurements from the shallow and deep systems. They all met wetland hydrology criteria (e.g., water within 30 cm of land surface for 5% of the growing season) during the early portion of the growing season despite the lack of appreciable regional groundwater discharge into the wetland root zones. Although root-zone duration analyses did not fit a lognormal distribution previously noted in groundwater-dominated wetlands, they were able to discriminate between the plant communities and showed that wet prairie communities had shorter durations of continuous soil saturation than sedge meadow communities. These results demonstrate that the relative rates of groundwater outflows can be important for wetland hydrology and resulting wetland type. Thus, regional stresses to the shallow groundwater system such as pumping or low Great Lake levels can be expected to affect even drier wetland types

    Observables and a Hilbert Space for Bianchi IX

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    We consider a quantization of the Bianchi IX cosmological model based on taking the constraint to be a self-adjoint operator in an auxiliary Hilbert space. Using a WKB-style self-consistent approximation, the constraint chosen is shown to have only continuous spectrum at zero. Nevertheless, the auxiliary space induces an inner product on the zero-eigenvalue generalized eigenstates such that the resulting physical Hilbert space has countably infinite dimension. In addition, a complete set of gauge-invariant operators on the physical space is constructed by integrating differential forms over the spacetime. The behavior of these operators indicates that this quantization preserves Wald's classical result that the Bianchi IX spacetimes expand to a maximum volume and then recollapse.Comment: 23 pages, ReVTeX, CGPG-94/6-3, UCSBTH-94-3

    Purification and properties of an erythrocyte hemoprotein with a unique prosthetic group

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    1. 1.|A unique hemoprotein has been isolated from a hemolysate of normal human erythrocytes by a procedure which involves (NH4)2SO4 precipitation and chromatography on Amberlite CG-50, DEAE-cellulose, Bio-Gel P-60, and Bio-Gel P-30.2. 2.|The purified hemoprotein appeared homogeneous on ultracentrifugation although small amounts of impurities were detected by polyacrylamide gel electrophoresis. The molecular weight was estimated to be 21 000 by gel filtration. Absorption maxima were located at 416 m[mu] for the oxidized form, 430 m[mu] for the CN- complex of the oxidized form, 434 m[mu] for the reduced form, and 425 m[mu] for the CO derivative of the reduced form. The reduced pyridine hemochrome of the isolated prosthetic group has maxima at 434, 540, and 579 m[mu], clearly indicating that the protein possesses a previously unrecognized heme.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32697/1/0000064.pd

    Generalized Sums over Histories for Quantum Gravity I. Smooth Conifolds

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    This paper proposes to generalize the histories included in Euclidean functional integrals from manifolds to a more general set of compact topological spaces. This new set of spaces, called conifolds, includes nonmanifold stationary points that arise naturally in a semiclasssical evaluation of such integrals; additionally, it can be proven that sequences of approximately Einstein manifolds and sequences of approximately Einstein conifolds both converge to Einstein conifolds. Consequently, generalized Euclidean functional integrals based on these conifold histories yield semiclassical amplitudes for sequences of both manifold and conifold histories that approach a stationary point of the Einstein action. Therefore sums over conifold histories provide a useful and self-consistent starting point for further study of topological effects in quantum gravity. Postscript figures available via anonymous ftp at black-hole.physics.ubc.ca (137.82.43.40) in file gen1.ps.Comment: 81pp., plain TeX, To appear in Nucl. Phys.
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