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

Her Voice Matters: Life Histories of Black Women Teachers’ Working Conditions

This study explored Black women’s lived experiences as teachers in urban schools during the era of 21st-century education reform. It centers around the relationships between Black women teachers (micro), their working conditions in low-performing urban schools (mesa), and neoliberal education policies (macro) that affect their work. The theoretical frames were Black feminist thought and critical race theory. The research questions were as follows: first, what are the working experiences of Black women teachers of tested subjects in low-performing urban public schools and, second, how do socio-political factors affect their working conditions? The research design was qualitative and included narrative inquiry and life history. Key findings were leadership, teacher autonomy, camaraderie, and collaboration, and student behavior. The Black women of this study want better leadership, autonomy, a pathway that does not lead to principalship but out of the classroom, self-care, and wellness. The implication for social change is educational leadership that uses adaptive leadership and social justice leadership that requires leaders to have emotional intelligence, social-political awareness, and activism. Educational leadership must stop taking its cues from big corporations, politicians, and businesspeople. The practice of standardized testing as ruler of all things public education must cease because it negates the human experience. The implication for practice is to honor the experiences and voices of Black women teachers, retain current Black women teachers, and recruit new Black women teachers otherwise Black women teachers are on the verge of extinction. Innovation in public education must include new ways for students, teachers, and leaders to thrive in an ever-changing world. Future research needs to include more qualitative data from Black women teachers’ working conditions and experiences through the lenses of critical race theory and Black feminist thought. This dissertation is available in open access at AURA: Antioch University Repository and Archive (https://aura.antioch.edu/) and OhioLINK ETD Center (https://etd.ohiolink.edu)

New and Old Tests of Cosmological Models and Evolution of Galaxies

We describe the classical cosmological tests, such as the Log$N$-Log$S$, 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