Typescript. / Bibliography: leaves [144]-149. / xi, 149 l illus

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VLF waves propagate in the Earth-ionosphere waveguide (EIW). The EIW is bounded below by the surface of the Earth and above by the ionospheric D-region (50–90 km altitude). The conditions for wave propagation in the EIW are studied and derived specifically for VLF propagation. The D-region is maintained by shortwave solar radiation that ionises the neutral atmosphere. The Wait parameters, H′ (reflection height) and (sharpness), describe the lower boundary of the D-region. Any enhancement in solar X-rays modifies these parameters, leading to a change in the propagation conditions for VLF signals. The effect of the terminator is presented where, it is found to narrow the depression of the monthly averaged diurnal amplitude profile from summer to winter. A series of solar flares were identified of which two case studies are presented. H′ and are calculated from the VLF signals by the Long Wave Propagation Code (LWPC). It is found that H′ decreased and increased at the time of flare. Once H′ and are obtained, the electron density profile can be constructed which is of crucial importance for VLF waves propagating in the EIW. The gradient of the electron density profile is found to increase as increases. It’s found that all the modal interference minima are moved towards the transmitter at the time of the flare. For flares of great magnitude, extrapolation is required to classify the flare in a magnitude class using VLF data. The change in the phase of the VLF signal is found to be linearly proportional to the change in the X-ray flux. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2009.

Thesis (Ph.D.) - University of Glasgow, 2008. / Ph.D. thesis submitted to the Department of Physics and Astronomy, Faculty of Physical Sciences, University of Glasgow, 2008. Includes bibliographical references.

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A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Aeroallergens are implicated in the pathogenesis of eosinophilic esophagitis, which has a recurrent or relapsing nature. We aim to determine the incidence of seasonal disease recurrence, referred to as flares, of eosinophilic esophagitis in patients in Arizona with eosinophilic esophagitis in remission, and to characterize the presence of allergy and other disease co‐morbidities in patients that experience disease flare. A retrospective study was performed by analyzing data from visits of patients aged 5 to 18 years coded for eosinophilic esophagitis in remission seen by the Phoenix Children’s Hospital Pediatric Gastroenterology Department between June 2010 and June 2011. The data included 148 patients and 326 clinical visits. Data identified demographic information, allergy, and other disease co‐morbidities. Arizona seasons were defined as: spring from February 15 to June 15, and fall from September 1 to November 30, according to the typical pattern of allergen pollination. To analyze incidence and season of flares, statistical methods used included the Chi‐square tests and logistic regressions. Ninety‐four of 148 patients (63.5%) flared during the study period. An increased incidence of flares in the fall compared with other seasons was statistically significant (p = 0.041). Flares in the spring also had an increased incidence. Of the 94 patients that flared, 70 patients (74.5%) had environmental allergy, 83 (88.3%) had food allergy, and 66 (70.2%) had both environmental and food allergy. Our findings suggest a role for seasonal environmental allergens in the pathogenesis of eosinophilic esophagitis and disease flares in children in Arizona, particularly those with food allergy, environmental allergy, or both.

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Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [123]-125).