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Objective: Snoring and obstructive sleep apnea (OSA) are common disorders. Snoring associated with excessive daytime sleepiness is the most prevalent symptoms of OSA. Heart rate variability (HRV) is altered in patients with OSA and the degree of alteration may be linked to the severity of OSA. Alterations in HRV in 24 hour tachograms have recently been used in screening OSA patients. Autonomic components causing HRV can be reliably studied using spectral analysis techniques involving fast Fourier transformation (FFT). Methods: Twenty-three subjects, 13 with severe OSA and 10 controls matched for age and body mass index, were selected from patients who had undergone polysomnography (PSG) for snoring at Sultan Qaboos University Hospital, Oman. A 24- hour electrocardiogram (ECG) Holter recording was done at home, starting at 10am. Spectral analysis of ECG from sleep Holter and PSG recordings was analysed using fast Fourier transformation (FFT). Results: The ECG RR intervals of snorers with OSA were significantly shorter than in snorers without OSA (p

The ability to compare two biological sequences is extremely valuable, as matches can suggest evolutionary origins of genes or the purposes of particular amino acids. Results of such comparisons can be used in the creation of drugs, can help combat newly discovered viruses, or can assist in treating diseases. Unfortunately, the rate of sequence acquisition is outpacing our ability to compute on these data. Further, traditional dynamic programming algorithms are too slow to meet the needs of biologists, who wish to compare millions of sequences daily. While heuristic algorithms improve upon the performance of these dated applications, they still cannot keep up with the steadily expanding search space. Parallel sequence search implementations were developed to address this issue. By partitioning databases into work units for distributed computation, applications like mpiBLAST are able to achieve super-linear speedup over their sequential counterparts. However, such implementations are limited to clusters and require significant effort to work in a grid environment. Further, their parallelization strategies are typically specific to the target sequence search, so future applications require a reimplementation if they wish to run in parallel. This thesis analyzes the performance of two versions of mpiBLAST, noting trends as well as differences between them. Results suggest that these embarrassingly parallel applications are dominated by the time required to search vast amounts of data, and not by the communication necessary to support such searches. Consequently, a framework named gridRuby is introduced which alleviates two main issues with current parallel sequence search applications; namely, the requirement of a tightly knit computing environment and the specific, hand-crafted nature of parallelization. Results show that gridRuby can parallelize an application across a set of machines through minimal implementation effort, and can still exhibit super-linear speedup. Master of Science

During sepsis, endotoxins are released into the circulation which cause the activation of both cellular and humoral mediators of inflammation. Following activation of the cytohumoral cascade of sepsis the transit time of leukocytes through the microvasculature of the heart is increased. Increased transit time contributes to the retention of increased numbers of activated leukocytes in the heart. Leukocytes are retained primarily within the capillaries of the heart. The neutrophil fraction of leukocytes is slowed and retained to a much greater extent than the lymphocyte fractions. The retention of activated neutrophils is mediated more by the effects of humoral inflammatory mediators on the heart than on the neutrophils themselves. The retention of increased numbers of activated neutrophils within the capillaries of the heart is associated with the development of myocardial edema and myocyte structural changes. These myocardial changes are associated with decreased myocardial contractile function. Reduced myocardial contractility contributes to the pathogenesis of the septic shock state which increases the mortality due to sepsis. Exclusion of activated neutrophils from the capillary circulation of the heart during sepsis protects the myocardium from pathologic changes associated with sepsis and decreases the loss of myocardial contractile function.