3,977 research outputs found
Conference Presentation of Transcendence and Epistemology for the 2005 Centre of Theology and Politics Annual Conference
This paper argues that a Platonistic turn to religion would enable the epistmology of transcendence to ground Western thought in meaningful metaphysics
Doctor of Philosophy
dissertationSudden cardiac arrest (SCA) is a leading killer in the United States. A large number of patients experience SCA outside of hospitals where there is an inherent delay in treatment due to slow first response times. In the out-of-hospital setting, ventricular fibrillation (VF)-induced SCA (VF-SCA) is the most common context in which the event manifests. VF leads to chaotic electrical and hence contractile function of the heart resulting in loss of cardiac output causing ischemia. Left untreated, electrical activity rapidly deteriorates, culminating in complete electrical failure or asystole. Survival rates for patients found in asystole are a mere 1%: asystole is a death sentence. Despite the high event and death rates of VF-SCA, little is known concerning the mechanisms of electrical failure. This dissertation represents the first concerted effort to understand the pathophysiology of electrical failure. The work contained herein can be divided into three projects. These projects were conducted in whole animal and isolated whole heart models of VFSCA. The first is a detailed examination of the complex patterns of electrical failure in VF-SCA. I found a highly complex pattern of electrical failure spanning the intra- and interchamber heterogeneities in three-dimensions. Second, I investigated the contributions of two canonical yet untested theories of electrical failure during VF-SCA: hyperkalemia and ATP-sensitive potassium channel (KATP) opening. I reached the surprising conclusion that neither hyperkalemia nor KATP opening-individually or combined-can explain the pattern of electrical failure in VF-SCA. Third, I investigated the effect of increasing metabolic demand on electrical failure during VF-SCA through increased p-adrenergic stimulation and excitation rate. The findings point toward a necessity to reexamine current resuscitation protocols. Specifically, the use of epinephrine (an α-and β-adrenergic agonist) may promote electrical failure during treatment of VF-SCA leading to increased mortality
Laboratory Experimentation and Numerical Modeling to Enhance Drainage in Geotextile Tubes
ABSTRACT
Laboratory Experimentation and Numerical Modeling to Enhance Drainage in Geotextile Tubes
Jonah G. Tyson
Geotextile fabrics are commonly used in the dewatering and filtration of high-water content geomaterials. Acid Mine Drainage (AMD) sludge is a geomaterial and has increasing production volumes in West Virginia. The WVDEP has large sludge storage sites for dewatering and long-term disposal. Currently the AMD is treated then transferred by pumping the material into geobags for long-term disposal in tubular shape geotextile bags that dewater the sludge. The current design of the geobags limit the pathways for the water to filter out due to the quality of the material. This research investigates the geotextile fabrics currently used and explores options to insert internal lateral drains to shorten drainage paths and accelerate dewatering.
AMD sludge was collected from the field to determine the current geotextile filtration and dewatering efficiencies with and without polymer additives. Analysis of column filtration tests concluded that a nonwoven geotextile exhibited the highest filtration efficiency (\u3e91%) and a relatively efficient drainage hydraulic conductivity (1.5x10-3 cm/s) for all permutations tested. The influence of polymer dosing on the AMD sludge indicated that for the no-polymer dose condition and a woven geotextile, the sludge hydraulic conductivity stabilized at 3x10-4 cm/s after approximately 50 hrs but had a filtration efficiency of 75 % particle retention. In contrast, the 20 ppm cation polymer dosed sludge exhibited a hydraulic conductivity at 3x10-5 cm/s within 150 hrs and a filtration efficiency of 91%. The polymer dosed sludge is preferred for minimizing solids pass through for environmental permit compliance.
Field in situ moisture and total solids percentage testing was performed on several AMD sludge filled geobags. Results indicated that dewatering trends are not consistent between bags and there was no clear placement location or position for installing internal lateral drains to enhance drainage
New and Old Tests of Cosmological Models and Evolution of Galaxies
We describe the classical cosmological tests, such as the Log-Log,
redshift-magnitude and angular diameter tests, and propose some new tests of
the evolution of galaxies and the universe. Most analyses of these tests treat
the problem in terms of a luminosity function and its evolution which can lead
to incorrect conclusions when dealing with high redshift sources. We develop a
proper treatment in three parts. In the first part we describe these tests
based on the isophotal values of the quantities such as flux, size or surface
brightness. We show the shortcomings of the simple point source approximation
based solely on the luminosity function and consideration of the flux limit. We
emphasize the multivariate nature of the problem and quantify the effects of
other selection biases due to the surface brightness and angular size
limitations. In these considerations the surface brightness profile plays a
critical role. In the second part we show that considerable simplification over
the complicated isophotal scheme is achieved if these test are carried out in
some sort of metric scheme, for example that suggested by Petrosian (1976).
This scheme, however, is limited to well resolved sources. Finally, we describe
the new tests, which use the data to a fuller extent than the isophotal or
metric based tests, and amount to simply counting the pixels or adding their
intensities as a function of the pixel surface brightness, instead of dealing
with surface brightness, sizes and fluxes of individual galaxies. We show that
the data analysis and its comparison with the theoretical models of the
distributions and evolution of galaxies has the simplicity of the metric test
and utilizes the data more fully than the isophotal test.Comment: 29 pages including 8 figures.
http://www-bigbang.stanford.edu/~vahe/papers/finals/newtest.ps. To appear in
ApJ, Oct. 199
LSST optical beam simulator
We describe a camera beam simulator for the LSST which is capable of
illuminating a 60mm field at f/1.2 with realistic astronomical scenes, enabling
studies of CCD astrometric and photometric performance. The goal is to fully
simulate LSST observing, in order to characterize charge transport and other
features in the thick fully depleted CCDs and to probe low level systematics
under realistic conditions. The automated system simulates the centrally
obscured LSST beam and sky scenes, including the spectral shape of the night
sky. The doubly telecentric design uses a nearly unit magnification design
consisting of a spherical mirror, three BK7 lenses, and one beam-splitter
window. To achieve the relatively large field the beam-splitter window is used
twice. The motivation for this LSST beam test facility was driven by the need
to fully characterize a new generation of thick fully-depleted CCDs, and assess
their suitability for the broad range of science which is planned for LSST. Due
to the fast beam illumination and the thick silicon design [each pixel is 10
microns wide and over 100 microns deep] at long wavelengths there can be
effects of photon transport and charge transport in the high purity silicon.
The focal surface covers a field more than sufficient for a 40x40 mm LSST CCD.
Delivered optical quality meets design goals, with 50% energy within a 5 micron
circle. The tests of CCD performance are briefly described.Comment: 9 pages, 9 figure
Corrigendum: hypoxic induced decrease in oxygen consumption in cuttlefish (Sepia officinalis) Is Associated with minor increases in Mantle Octopine but no changes in markers of protein turnover
Corrige o artigo http://hdl.handle.net/10400.1/10858 [This corrects the article DOI: 10.3389/fphys.2017.00344.].info:eu-repo/semantics/publishedVersio
Characterising Usage Patterns and Privacy Risks of a Home Security Camera Service
Home security cameras (HSCs) are becoming increasingly important in protecting people's household property and caring for family members. As an emerging type of home IoT devices, HSCs are distinct from traditional IoT devices in that they are often installed in intimate places, detecting movements constantly. Such close integration with users' daily life may result in distinct user behavioral patterns and privacy concerns. To explore this, we perform a detailed measurement study based on a large-scale service log dataset from a major HSC service provider. Our analysis reveals unique usage patterns of HSCs, including significant wasted uploads, asymmetrical upload and download traffic, skewed user engagement, and limited watching locations. We further identify three types of privacy risks in current HSC services using both passive logs and active measurements. These risks can be exploited by attackers, through observing only the traffic rates of HSCs, to infer the working state of cameras and even the daily activity routine in places where the camera is installed. Moreover, we find the premium users who pay an extra fee are especially vulnerable to such privacy inferences. We propose countermeasures from the perspectives of susceptible users and HSC providers to mitigate the risks
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Shapes of Normal and Reverse Flow Injection Signals: On-Line Formation of Iodine from Iodate, Iodide, and Hydrogen Ion
Signal shapes for the on-line formation of iodine from iodate, iodide and hydrogen ion in a single-channel manifold using large-volume slug and large-volume time-based injections have been determined using visible spectrophotometry. These large injection volume studies were made first as a means of understanding the shapes of normal and reverse flow injection signals obtained at more conventional injection volumes (10--100 µI). The signal shapes at large injection volumes were determined for the six possible combinations of the reagents in the two solutions serving as carrier stream and injectate so that one solution contained two reagents and the other solution one or two reagents. Each combination of reagents represents two complementary systems in which the roles of each solution as carrier stream and injectate are reversed. At these large injection volumes each signal consisted of two independent peaks caused by dispersion at the front and rear boundaries of the injected bolus. The signals obtained for the time-based injections for complementary systems were identical in shape and height except that the front peak of one system was identical with the rear peak of its complementary system and vice versa. Clearly, at such large injection volumes the terms normal flow injection (nFI) and reverse flow injection (rFI) have no real meaning, the shape of each independent peak being determined by the composition and relative positions of the two solutions forming the boundary at which the peak is formed. For slug injections, similar shapes were observed but the peak heights were affected markedly by the greater dispersion at the rear boundary which travels further than the front boundary. This comparison of the signals obtained with slug and time-based injections, despite different flow-rates being used for the two modes of injection, clearly shows the effect of the unequal dispersion at the two boundaries in the slug injection method. Examination of the signals obtained with time-based injection, however, clearly indicates that the solution compositions, and their relative positions in the flow stream, also affect the shapes and relative heights of the front and rear peaks. The shapes of all these signals are illustrated. The effect of reducing the slug injection volume stepwise from 2 ml to 100 µI was studied for the 103-J- \u3c H+ and H+ \u3c 103-1- systems(\u3c denotes the direction of the boundary shape). This indicated that the shapes and heights of the single peaks observed in the rFI and nFI formation of iodine carried out at the more conventional lower injection volumes are determined by dispersion at the rear and front boundaries of the bolus, respectively. Hence, as the two peaks observed in a large-volume injection merged as the injection volume was decreased, the major peak predominated and became the observed signal. The use of a much smaller injection volume was necessary in rFI than in nFI in order to obtain a single peak
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