Gravitational Wave Astrophysics with Compact Binary Systems

In this dissertation, I present two studies in the field of gravitational wave astrophysics applied to compact binary systems. In the first project, I investigate simulated encounters between a binary system comprised of two stellar mass black holes with a galactic supermassive black hole. It is found that binaries disrupted by the supermassive black hole form extreme mass ratio inspirals (EMRIs), which would begin with very high eccentricity, e ≈ 1 − O(10−2), but circularize dramatically by the emission of gravitational wave radiation. At the time when the stable orbit turns over to a plunge orbit, the EMRIs still have some small residual eccentricity, e ≈ 0.05 on average, which is slightly larger than previous estimates. The surviving binaries are classified based on their final relation with the supermassive black hole. When inspecting the merger lifetime of the surviving binaries, a mean new merger lifetime of ˜ T = 0.8T0 is found. Factoring in this new lifetime with other relevant data, I calculate the merger rate of these systems in the range of the advanced Laser Interferometer Gravitational Wave Observatory to be about 0.25 yr−1, which represents a small percentage of the current predicted CBC rates. In the second project I propose and explore a new method of estimating the radius of the accretion disc in cataclysmic variable binary systems though the use of coupled electromagnetic and gravitational wave observations. By identifying the angle of the hot spot formed by the impact of the accretion stream with the disc, φHS, the radius of the disc can be recovered. I test the proposed method against fully simulated lightcurve output, as well as the true observed AM CVn lightcurve. In both cases, I find our method capable of estimating the disc radius to high precision. I calculate a disc radius of ˆRD/a ≈ 0.476°”0.025 for the fully simulated data and ˆRD/a ≈ 0.481 °” 0.05 for the true lightcurve data. These estimates agree with the accepted value of RD = 0.478a within the uncertainties, and differ from the accepted value by 0.4% and 0.6%, respectively. Because this method does not rely on eclipses, it will be applicable to a much broader population of binaries

Herramienta web para la gestión de comandos en las centrales telefónicas

REMA es una aplicación Web diseñada para administrar todos los movimientos en la configuración de los abonados de servicio telefónico pertenecientes a la red de UNE EPM Telecomunicaciones. En la actualidad UNE cuenta con tres tipos de centrales telefónicas digitales (FETEX-150, AXE-10, NEAX-61S), cada una de estas centrales telefónicas maneja lenguajes diferentes y la forma de extracción de reportes es a través de comandos, para los usuarios que requieren la información no es fácil interpretar los comandos y para traducirlos al lenguaje común deben realizar un requerimiento al operador de cada central, éste trámite puede llegar a tardar hasta 15 días, dado que los operadores de las centrales tienen otras actividades prioritarias dentro de su labor. Con el fin de dar solución a éste problema nace el sistema REMA, el cual administra todos los comandos de abonados de los 3 tipos de central, proporcionando al usuario final la información en un lenguaje unificado y amigable. Con éste desarrollo se optimiza el tiempo, debido a que los usuarios interesados en la información pueden obtener respuesta inmediata al consultar la Web, ésta información es de fácil comprensión para cualquier usuario y por lo tanto no requiere la intervención de los operadores de la central para la comprensión de comandos.Pregrad

Dose Variation To Critical Points In Low Dose Rate Intracavitary Brachytherapy Of Cervical Cancer As Justification For Incident Learning

Background: Low Dose Rate (LDR) brachytherapy necessitates a more extended treatment duration. This technique maintains the patient on the treatment machine for a longer length of time, which may cause changes in the applicators' position due to vaginal packing soaking and patient movement for incident learning justification. Objective: The purpose of this study is to evaluate pre- and post-dosage variation to points 'A' and 'B,' as well as vital organs (i.e. bladder and rectum), for low dose rate (LDR) brachytherapy at Komfo Anokye Teaching Hospital and justify the need for incident learning system. Method: Forty (40) patients with invasive cervical cancer were treated with LDR brachytherapy equipment (A Curietron Cesium Manuel (AMRA)-France, CA 98.22) to point 'A' at doses ranging from 30 to 35 Gy. Adult patients selected for the study ranged from 25 to 60 years simulated. For each patient, orthogonal images of anterior-posterior (AP) and (LAT) were taken by positioning the patient on the Varian Acuity Simulator Couch at 00 and 900, respectively, and two sets of orthogonal images (before and after treatment), in each case, were considered. The treatment was then planned using the AP and LAT images obtained based on the four arrangements used, namely 1-2-5, 1-3-5, 1-4-5, and 1-5. The treatment planning system used for the study was the Prowess Panther system 4.6. Results: The dosage disparity at point 'A' was determined to be 1.16 per cent, which is highly commendable compared to previous research that established dose variations of 2%, 35%, 8%, and 20%. In this study, the dosage variation at point B was 0.75 per cent. The bladder and rectum had average alterations of 2.32 per cent and 0.30 per cent, respectively. Conclusion: The difference observed between prescribed, and deposited dosage was 2.11 per cent for quality assurance and incident learning reasons. Unrealistic expectations, reliance on reminders and quick remedies, and faults in the systemic view of failure were discovered and addressed as managerial issues. It is critical not to underestimate these difficulties because they are frequently significantly more severe than the technical issues being addressed. Incident issues were not recorded per patients under review, but near misses and non-conformance were observed. The geometric variances between the Intracavitary Brachytherapy Treatment (ICBT) applicators and the essential organs change during the treatment process, resulting in dosage changes. Does variance is within the required standard limits; it can be stated that Komfo Anokye Teaching Hospital's practice satisfies the international standard and is an intrusion into the Directorate Incident Learning System

Research and Development for Improved Cassava Varieties in Ghana: Farmers’ Adoption and Effects on Livelihoods

The importance of Cassava in the food systems of Ghanaians cannot be underestimated. As a main staple crop, Cassava contributes about 22% and 30% to the Agricultural Gross Domestic Product (AGDP) and daily calories intake respectively. Per capita consumption of 152 kg makes it the highest among all food crops. Due to Cassava’s importance, there have been lots of attention paid to it by the Government and Donor agencies towards its improvement. This has yielded substantial results in terms of the development of cassava varieties and good agronomic practices. This chapter reviewed cassava technologies development in Ghana, adoption of these technologies by smallholder farmers, and livelihood implications. Results generated showed that Research and Development since 1993 has developed, released, and disseminated 25 new cassava varieties to smallholder farmers. Average cassava yields have increased from about 14 t/ha in 2009 to 21 t/ha in 2018. Partial budget analysis showed that smallholder farmers’ profitability has increased over the years from GH₵644.32 (about US$111) in 2009 to GH₵5243.27 (about US$ 904) in 2018. Again, the crop is gradually gaining attention as an industrial crop for flour, starch, and alcohol production, a drive that would further improve on returns to farmers. It is a food security crop because it is robust, produces more per unit area, and versatile for multiple usages in household foods and derivatives. It is recommended that continuous policy consideration on cassava in national agricultural agenda setting is essential

The impact of multiple single day blood pressure readings on cardiovascular risk estimation: The Atherosclerosis Risk in Communities study

To determine the magnitude of change in estimated cardiovascular disease risk when multiple same day blood pressure measurements are used in estimating coronary heart disease (CHD), heart failure (HF) and stroke risks

Detection of tissue remodelling by Fast Field-Cycling methods

Abstract 57Peer reviewedPublisher PD

The Atacama Cosmology Telescope: Dusty Star-Forming Galaxies and Active Galactic Nuclei in the Southern Survey

We present a catalog of 191 extragalactic sources detected by the Atacama Cosmology Telescope (ACT) at 148 GHz and/or 218 GHz in the 2008 Southern survey. Flux densities span 14-1700 mJy, and we use source spectral indices derived using ACT-only data to divide our sources into two sub-populations: 167 radio galaxies powered by central active galactic nuclei (AGN), and 24 dusty star-forming galaxies (DSFGs). We cross-identify 97% of our sources (166 of the AGN and 19 of the DSFGs) with those in currently available catalogs. When combined with flux densities from the Australian Telescope 20 GHz survey and follow-up observations with the Australia Telescope Compact Array, the synchrotron-dominated population is seen to exhibit a steepening of the slope of the spectral energy distribution from 20 to 148 GHz, with the trend continuing to 218 GHz. The ACT dust-dominated source population has a median spectral index of 3.7+0.62-0.86, and includes both local galaxies and sources with redshifts as great as 5.6. Dusty sources with no counterpart in existing catalogs likely belong to a recently discovered subpopulation of DSFGs lensed by foreground galaxies or galaxy groups.Comment: 13 pages, 8 figures, 4 table