title: Investigation of Partially Coherent Interaction in Fiber Bragg Grating Stabilized 980-Nm Pump Modules

contributor:
Cassidy, D. T.
Engineering Physics

subject:
partially coherent interaction
fiber Bragg grating
980-nm pump module

abstract: Partially coherent interaction of the feedback light with the field in the laser cavity is affirmed with the fiber Bragg grating (FBG) stabilized 980-nm pump lasers, on the contrast of normally accepted totally incoherent state of operation in the “coherence collapse” regime. Coherence parameter y was defined in this paper to identify the fraction of feedback light working coherently. It is shown that y can be determined by fitting the measured power-difference versus pumping-rate curve to the simulation results. Experiments confirm that coherence parameter y decreases while the distance between the FBG and the laser facet increases, and vice versa. While, if the device is kept operating in the “coherence-collapse” regime, y would not change with the amount of feedback. This work will be help to improve the performance of the high power FBG stabilized 980-nm pump laser.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Drug-Induced Ataxia: Effect of the Self-Administration Contingency

contributor:
Siegel, Shepard
Psychology

subject:
drug-induced ataxia
ataxia
self-administration
contingency

abstract: Some studies have demonstrated that the effects of a drug may be different, depending on whether the drug is self-administered or passively received by the subject. Most of the studies which have examined this phenomenon have not examined the effects of a drug following each of a series of administrations. Moreover, the mechanism mediating differences between self-administered and passively received drugs has not been determined. The present experiments used a yoked-control design to examine the development of tolerance to the ataxic effects of heroin and of ethanol in rats that self-administer the drugs and rats that passively received them. Results demonstrate that rats that passively received heroin, but not those that self-administered the drug, were significantly impaired following the initial administrations. During the first administration sessions, rats that self-administered ethanol were as impaired as their partners that passively received, but within a few sessions self-administering rats developed tolerance to the ataxic effect of the ethanol, while their yoked partners did not. The results also suggest that the faster tolerance development in rats that self-administered ethanol may have been mediated by differences in Pavlovian conditioning in these subjects, which demonstrated larger compensatory conditional responses in the form of “hypertaxia” than did their yoked partners. The results indicated that some component of the self-administration process contributed to the Pavlovian conditioning, and hence, faster tolerance development, of self-administering animals. The data suggest that studies in which drugs are passively received may overestimate the dose that is necessary to produce tolerance in self-administering animals. Models based on such studies, then, may require modification before they are applied to situations which involve self-administration of drugs.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Linewidth of Short External Cavity Semiconductor Lasers

subject:
short external cavity
semiconductor lasers

abstract: This thesis describes the development of a technique for measuring frequency noise of semiconductor lasers. Equivalent laser linewidths were calculated from frequency noise measurements on several InGaAsP lasers with short external cavities to give single mode operation. Conventional 250 um lasers demonstrated linewidths of about 125 MHz-mW, compressively strained quantum well lasers of commensurate length had linewidth of 37 MHz-mW, and 500 um strained quantum well lasers had linewidth of 18 to 28 MHz-mW with an apparent strain dependence. The short external configuration allowed selection of a number of laser modes. Measurement of linewidth variation with laser mode showed a 20% to 40% change over six to eight modes. The system was adapted to make measurements of the optical frequency tuning with fine external cavity length change. This measurement provided a novel means to estimate the linewidth enhancement factor and the reflectivity of the external cavity element. The estimated values of the linewidth enhancement factor for 250 um conventional and quantum well lasers were found to be in the correct ratio to account for the measured difference in linewidth.

abstract: Thesis

abstract: Master of Engineering (ME)


title: Multimode Optical Fiber Bragg Gratings: Modeling, Simulation and Experiments

contributor:
Huang, Wei P
Xu, Chang Q
Electrical and Computer Engineering

subject:
optical fiber Bragg grating
fiber Bragg grating
modeling
simulation

abstract: Telecommunication networks based on optical fiber technology have become a major information-transmission system, satisfying the growing demand for bandwidth due to increased internet traffic and other applications such as video on demand, etc. Fiber Bragg gratings (FBGs), in recent years, have emerged as critical components for enabling high-capacity transmission since their response can be tailored to meet the needs of specific applications. FBGs are currently the focus of intense research interest in both the fiber communications and sensing fields. Optical fiber Bragg grating structures in single-mode fiber (SMFBGs) have been studied extensively since the discovery of photosensitivity in germanium-doped silica fiber. They have been used in numerous applications ranging from wavelength-selective filtering in wavelength-division-multiple-access (WDMA) systems to temperature and strain sensing. To a lesser extent, Bragg gratings in multimode fibers have also received attention because of easy coupling with light sources. Most of the MMFBGs related research work has demonstrated the formation of a Bragg grating in a graded-index MMF and briefly reported the measured transmission spectrum. So far, there are few theoretical studies on Bragg gratings in multimode fibers. In this thesis, we investigate Bragg gratings in multimode optical fibers both theoretically and experimentally. A comprehensive numerical model for MMFBGs has been established and the corresponding computer simulation software (MMFBG simulator combined with mode solver) developed. The optical properties of MMFBGs were systematically studied for the first time using our own MMFBG numerical software package. It effectively assists the design modeling for MMFBG-based optical devices. Bragg gratings in multimode fiber were also investigated experimentally. Our theoretical simulation results show good agreement with experiments and offer the insightful explanations for the underlying physics of the device. First, the guided modes were modeled and simulated for step index multimode fibers and graded index multimode fibers with emphasis on parabolic fiber structure. These are popular, standard and commercially available MM fibers, and employed throughout our experiments. This allows us for the simulation of fiber characteristics such as cut-off wavelength, mode effective index, propagation constants and optical field distribution. It also allows for calculation of mode coupling coefficients by overlap integral between any chosen guided modes. Therefore, it serves as a powerful model for the design and analysis of optical fibers. Second, the generalized MMFBG coupled mode theory formalism is derived. The physical mechanism of the behavior of MMFBGs is studied and discussed. The general solution to the MMF Bragg grating problem is achieved by Runge-Kutta, Newton-Raphson and shooting numerical methods. Our theoretical treatment, in particular, offers the advantages which can deal with not only self-coupling but also more complicated cross-coupling interactions and can solve arbitrary large number of mode coupling problems throughout the entire spectra simultaneously for multimode FBGs, thus allowing for a precise and quantitative study of MMFBGs. Such an intensive multimode fiber Bragg grating physical modeling and simulations have not been reported previously. It provides an effective means for the design and analysis of optical fiber devices based on Bragg gratings. Third, the optical properties of multimode FBGs were studies experimentally. Numerical predications of the grating spectral characteristics under fabrication and experimental condition are calculated. The results of the numerical calculations are compared with experimentally measured spectra of multimode gratings written by ultraviolet irradiation of deuterium-sensitized fiber with grating reflectivities ranging from 78% to 99.39%. Good agreement is obtained between the theoretical simulations and the experimental results. Thus, we provide quantitative explanations for the observed experimental phenomena. These explanations give both physical insight and a more complete understanding of the nature of the interaction between the wave propagation and multimode fiber gratings. Furthermore, the spectral simulation of the actual experiments prepares a theoretical guidance for the advanced experimental investigation and also presents a step toward MMFBG device design. Finally, the optical properties of MMFBGs were also studied theoretically. To our knowledge, this is the first detailed analysis and thorough investigation on grating characteristics in MMF. It is demonstrated that the transmission and reflection spectra of fiber Bragg gratings in multimode optical fibers strongly depend on the length of grating, index modulation, period of grating, mode excitation condition and physical structure of MMF. The simulation results allow us to deeply comprehend and visualize the more sophisticated behavior within a multimode fiber grating, and will also allow us to confidently predict and evaluate the performance of more complex structure MMFBGs. It provides the fundamental principles for designing the targeted spectrum performance and settles the theoretical rationale for realizing the practical applications. Overall, the comprehensive numerical model and MMFBG solver package developed in this thesis opens a clear and broad window for understanding MMFBG mechanisms from the physical point of view. Various simulation results and spectral characteristics have been researched and discussed under both ideal and experimental conditions for the purpose of experimental analysis and device design. The results of our study indicate that a new class of potential applications based on MMFBGs can be expected in optical fiber sensors and advanced communication systems.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Some Observations on Teleost Respiration with Emphasis on the Gill Filament Musculature and the Respiratory Centres of the Brain

contributor:
Kleerekoper, H.
Biology

subject:
teleost respiration
gill filament musculature

abstract: Two aspects of teleost respiration have been emphasised in this investigation. Firstly the gill filaments themselves were observed in order to determine whether or not they played an active role in the ventilation of the gill lamellae. The musculature of the filaments was studied, using visual and electronic methods, and continual muscular activity was noted. Two possible functions of these muscles of the gill filaments have been proposed. Secondly, the brain centres which initiate and maintain the respiratory rhythm were investigated. The neural mechanism was found to be much more complex than had hitherto been suspected in the literature.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Kinetic Isotope Effects in Aromatic Bromination Reactions

subject:
kinetic isotope effect
aromatic bromination

abstract:
Both bromodeprotonation and bromodesulphonation occur during aqueous bromination of sodium p-methoxybenzenesulphonate, A, and potassium l-methylnaphthalene-4-sulphonate, B. Extensive kinetic studies reported here suggest that bromodesulphonation of A proceeds by a two-step process with Br2 as the brominating species, but do not
completely exclude Br+ (or H2OBr+) acting in either a one- or two-step process. For B, the kinetic data can be interpreted by either a one- or two-step process with Br2 as the brominating species. Kinetic sulphur isotope effects have been measured for the bromodesulphonation of A and B and found to vary with bromide-ion concentration,
thus strongly supporting the two-step process involving molecular bromine. The kinetic results for the bromodeprotonation of A cannot distinguish between a one- and two-step process involving Br2l the two-step mechanism has been confirmed by the observation of
a variation in kinetic hydrogen isotope effect with bromide-ion concentration.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: An Analysis of Rodent Reservoirs of Plague During the Second Pandemic: Shifting Focus Towards a Multi-host and Multi-mechanism Model of Plague Maintenance and Reintroduction in the Past

contributor:
Poinar, Hendrik
Anthropology

subject:
Plague
second pandemic
Mediterranean littoral
rodent reservoirs

abstract: The second pandemic persisted for 500 years throughout Europe and some regions of Africa and Asia and far surpasses the first and third pandemics in terms of temporal and spatial breadth. It is still unclear what mechanisms facilitated the long-term maintenance and continued disease reintroductions experienced during the second pandemic. Many researchers believe it was the spread of plague infected Rattus spp. via trade routes, while others are beginning to support a model that reflects modern plague ecology such that plague was maintained in local rodent reservoirs in the Mediterranean region or Europe following its 14th century introduction. This study accumulated a list of rodent species known to host plague and analyzed host characteristics to determine what traits allow rodents to function as successful reservoir species. In addition, this study analyzed the ancient DNA within rodent remains in search of Yersinia pestis to add to the history of the pathogen. The results of this study demonstrate that there are 45 non-Rattus rodent species known to host plague within a modern context. Although ancient Y. pestis DNA was not identified from zooarchaeological remains within this study, it is clear that rodent reservoirs were key players in past plague pandemics. When viewed through the lens of a single model (i.e. trade routes or human-ectoparasites), several questions about past plague maintenance remain unanswered. This study shows that a more complex composite model is best fit to describe the 500-year reign of the second pandemic and the quiescent periods that extended between the cyclical disease reintroductions. This study presents the first comprehensive, interactive, and publicly available online database of rodent reservoirs to aid in future research and emphasizes the need to investigate a multi-mechanism model of plague maintenance and reintroduction in the past. With this research we facilitated a starting point for future studies, expanded the current knowledge on rodent reservoirs of plague, and contributed a valuable discussion to the field of plague studies on regions that have thus far gone underserved in plague studies, such as the Mediterranean littoral.

abstract: Thesis

abstract: Master of Arts (MA)


title: Fabrication and Properties of Polypyrrole Nanocylinders

contributor:
Datars, W. R.
Physics

subject: fabrication properties polypyrrole nanocylinders

abstract: Polypyrrole nanocylinders were fabricated by chemically synthesizing polypyrrole within the pores of nanoporous polycarbonate particle track-etched membranes and alumina membranes. The morphology of the nanostructures was characterized by transmission electron microscopy and scanning electron microscopy. The polycarbonate membrane-templated nanocylinders were cigar-shaped, with the diameter at the center being up to 2.5 times the diameter at the ends. The nanostructures produced in alumina membranes were linear aggregates of blobs. The electrical conductivity of the nanocylinders was measured by leaving the nanocylinders embedded in the insulating template membrane and measuring the trans-membrane resistance. The smallest diameter polycarbonate membrane-templated nanocylinders exhibited a slightly lower conductivity relative to the larger diameter nanocylinders. The temperature dependence of the resistance with and without the application of a magnetic field was in accordance with Mott variable range hopping at temperatures above 5 ± 1 K and Efros-Shklovskii variable range hopping at temperatures below 5 ± 1 K. Based on the measurements in the Mott regime, the localization length, the density of states at the Fermi energy, and the temperature dependence of the average hopping distance were calculated.

abstract: Thesis

abstract: Master of Science (MS)


title: Projections of hydrometeorological processes in Southern Ontario: Uncertainties due to internal variability of climate

contributor:
Arain, Muhammad Altaf
Earth and Environmental Sciences

subject:
Hydrological modelling
Southern Ontario
Internal variability
High flows
Climate change

abstract:
Flooding is a major concern for Canadian society as it is the costliest natural disaster type in Canada. Southern Ontario, which houses one-third of the Canadian population, is particularly affected by early spring floods following snowmelt. During the last three decades, there has been a shift in flooding events from March-April to earlier months due to earlier snowmelt coupled with extreme rain events. Hydrological models run with different scenarios of climate change suggest further enhancement of this shift in the future. These projections of streamflow are associated with a cascade of uncertainties due to the choice of Global Climate Models (GCM’s), climate change scenarios, downscaling methods or hydrological models. A large part of the uncertainty is also associated with internal variability of climate due to the chaotic nature of the climate system. Despite these uncertainties, little is known about the impact of atmospheric circulation on past streamflow in southern Ontario and how the internal variability of climate is expected to impact the overall uncertainties in the projections of the future hydrological processes.
In this thesis, the Precipitation Runoff Modelling System (PRMS), a semi-distributed conceptual hydrological model, was established in four watersheds in southern Ontario to assess the impact of atmospheric circulation on the modulation of streamflow and number of high flows. Recurrent meteorological patterns (Or Weather regimes), based on 500hPa geopotential height (Z500), have been first identified in Northeastern North America using the k-means algorithm. The occurrences of these weather regimes patterns were used to create a regime-normalized hypothetical temperature and precipitation dataset that have been used as input in PRMS. Then, to investigate the future evolution of the hydrological processes, PRMS was forced with temperature and precipitation from the 50-members Canadian Regional Climate Model Large Ensemble (CRCM5-LE), a dynamically downscaled version of CanESM2-LE. The 50-members were classified into different classes of similar change in average temperature, precipitation and streamflow to identify the corresponding large-scale patterns. The specific focus of this analysis was on winter high flows, with the identification of a heavy rain and warm index, that can help to explain the generation of winter high flows in southern Ontario. The future evolution of these hydrometeorological extreme events, calculated for each member of CRCM5-LE, was analyzed with respect to the corresponding k-means weather regimes calculated for each member of CanESM2-LE. Finally, the uncertainties in the projections of the hydrometeorological extremes from the 50-members ensemble were compared to other sources of uncertainties using an analysis of variance applied to 504 simulations in the Big creek watershed. The high flows were projected using seven sets of PRMS parameters, 11 CMIP5 climate models forced with 2 scenarios of climate change and the 50 members of CRCM5-LE.
The results, focusing on the winter season, showed that weather regimes High-Pressure (HP) and southerly winds (South) are associated with a higher average streamflow volume and high-flows frequency in the historical period. Regime HP is characterized by high geopotential height anomalies on top of the Great Lakes region together with higher temperature and precipitation amounts. Regime South is characterized by high Z500 anomalies in the Atlantic east coast and is associated with stronger southerly winds and higher precipitation amount in southern Ontario. The temporal increase in HP in the past contributed more than 40% of the increase in average streamflow in winter. In the future, all 50 members of CRCM5-LE ensemble produce an increase in January-February streamflow. 14% of the ensemble depict a larger streamflow increase due to increase in Z500 anomalies in the east coast. This pattern, well defined by the regimes South, is expected to become a major contributor in the generation of hydrometeorological extreme events in Southern Ontario in the future. Regime HP is expected to contribute less to the high-flows due to the disappearance of snow. Overall, the contribution of internal variability of climate to high flows will be stable through the 21st century, primarily due to an increase in rainfall as generators of high flow events. The results suggest that the regional representation of rainfall in the GCMs-RCMs chains will be a critical area to improve with great societal implications for floods.

abstract: Dissertation

abstract: Doctor of Science  (PhD)


title: A Study of the Relationship Between Poet and Patron During the Augustan Age

subject:
poet
patron
augustan age

abstract:
Thesis
Master of Arts (MA)


title: SOIL RESPIRATION DYNAMICS IN RESPONSE TO CLIMATE OSCILLATIONS AND SHELTERWOOD HARVESTING IN A TEMPERATE PINE FOREST

contributor:
Arain, M. Altaf
Geography and Earth Sciences

subject:
soil respiration
shelterwood harvest
Pinus strobus L
climate variability

abstract: Understanding forest carbon uptake and associated growth response is important for carbon sequestration and water management practices given the large quantities of carbon stored in forest ecosystems.  Climate variability and forest management practices influence the magnitude and rate of soil CO2 efflux; however, their combined effects are complex and not well understood.  This study investigated the response of soil CO2 efflux to the combined effects of climate variability, including those caused by climate oscillations, and shelterwood harvesting in a mature temperate white pine (Pinus strobes L.) forest, located near Lake Erie in southern Ontario, Canada.  Analyses indicated that local winter temperatures and precipitation were influenced by climate oscillations, which affected forest carbon dynamics.  After the shelterwood harvest removed approximately a third of the overstory canopy, no significant differences were found for soil temperature and soil moisture between the pre-harvesting (2008 to 2011) and post-harvesting (2012 to 2014) periods.  Despite similar climate conditions pre- and post-harvesting, soil CO2 effluxes post-harvesting were lower.  A Gaussian-Gamma specification model determined that heterotrophic (autotrophic) respiration decreased (increased) between pre- and post-harvesting, respectively.  Mineral-soil respiration were similar pre- and post-harvesting.  Soil CO2 efflux accounted for 78±9% of the annual ecosystem respiration (RE), derived using eddy-covariance fluxes.  However, the overall net ecosystem productivity showed no significant difference between pre- and post-harvesting.  This was attributed to an increase in the gross ecosystem productivity post-harvesting, compensating for the increased losses (i.e. increased RE).  This study highlights the complexities of measuring various components of ecosystem respiration after a disturbance, such as a harvest.  The knowledge gained from this study provides a better understanding of climate variability and shelterwood harvesting influences on ecosystem respiration and can be useful for forest managers focused on carbon sequestration and forest conservation.

abstract: Dissertation

abstract: Doctor of Science  (PhD)

abstract: Coniferous forest plantations in eastern North America are undergoing silvicultural management to enhance their carbon sequestration capabilities and native-tree species diversity.  This study investigated the combined influence of climate oscillations and shelterwood harvesting on soil carbon dynamics of a planted pine forest in southern Ontario, Canada.  Between pre- and post-harvesting, soil temperature and soil moisture did not show any significant differences.  However, soil CO2 effluxes in post-harvesting years were lower than pre-harvesting years.  A Gaussian-Gamma specification model determined that heterotrophic (autotrophic) respiration decreased (increased) post-harvesting and mineral-soil respiration was similar between pre- and post-harvesting.  An increase in ecosystem respiration post-harvesting, despite soil CO2 efflux decreasing and being the largest component, was primarily caused by the increase in autotrophic respiration due to enhancement in forest growth.  This study improved the understanding of forest carbon dynamics by highlighting the importance of accounting for all components, which may contribute to ecosystem respiration.  Results can be useful for forest management practitioners, specifically those focused on carbon sequestration and forest conservation.


title: Destruction of the Müller-Lyer Illusion as a Function of Procedure and Pretraining

contributor:
Newbigging, P.L.
Psychology

subject:
Müller-Lyer illusion
destruction

abstract: Two experiments were performed to investigate conditions affecting the Müller-Lyer illusion and its decrement with practice. The first experiment was a methodological study concerned with the setting of the variables before adjustment by the subject. The results indicated that the method employed may determine whether a decrement occurs with repeated trials. The evidence suggested the most suitable method to employ in the succeeding experiment. The second experiment was performed to investigate the effects of practice with another illusion figure on the magnitude of illusion on the Müller-Lyer figure. The practice figure was the same as the Müller-Lyer illusion figure except that circles were replaced by the obliques. It was found that the magnitude of the initial illusion is a decreasing monotonic function of the amount of preliminary training. This finding is interpreted as meaning that in pretraining subjects are practiced in disregarding the context (circles) of the horizontal lines of the figure and this transfers positively to the Müller-Lyer task.

abstract: Thesis

abstract: Master of Arts (MA)


title: Share: A Study of Heart Assessment and Risk in Ethnic Groups

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
heart assessment
risk
ethnic group

abstract:
Cardiovascular disease (CVD) is the major cause of death in Canada and most developed countries. One of the next major advances in reducing CVD morbidity and mortality will likely occur when the epidemiology and the pathophysiology of specific risk factors for atherosclerosis across diverse populations are better understood. It is now apparent that different ethnic groups have different risks of CVD mortality that cannot be accounted for by differences in risk factors like smoking, hypertension, hypercholesterolemia, and diabetes. Therefore, both from global and national perspectives, studies that explore reasons for ethnic differences in CVD rates are of major public health importance. The Study of Heart Assessment and Risk in Ethnic groups (SHARE) is a unique initiative designed to determine the prevalence of subclinical atherosclerosis and cardiovascular risk factors in South Asians and European Canadians. South Asians in Canada and in several countries have the highest rates of coronary heart disease (CHD) compared to any other ethnic groups in the world, and present a unique opportunity to test research hypotheses to discover emerging risk factors for atherosclerosis. SHARE builds upon previous cross-sectional studies that have examined the traditional CHD risk factor profile of South Asians, and extends this investigation to determine the prevalence of subclinical atherosclerosis in South Asians, and the contribution to its development from metabolic, fibrinolytic, nutritional, and psychosocial factors. This thesis represents a carefully designed research proposal to study CVD risk factors and subclinical atherosclerosis in South Asians and White Canadians. A pilot study to test the feasibility of this design was conducted over the past one year. The information obtained from this experience has led to further pilot studies and modification of the final proposal, which has recently been funded by the Medical Research Council of Canada. This cross-sectional study proses to use a stratified random sampling to identify potential South Asian and White Canadian participants in Canada. Ethnic specific sampling frames were created, in conjunction with Statistics Canada, by using a compact disc programme of public telephone directories. South Asian Canadians were identified by using a comprehensive list of last names, a method which is highly sensitive and specific to South Asian ethnicity. A sampling frame of Canadians of European origin matched by postal code to the South Asian sampling frame was also created. In the pilot study we recruited participants by mail and multiple telephone calls, and our results are comparable to other population-based studies who utilized similar methods of recruitment. However, it is likely that our contact rates may be improved and after seeking the advice of the York Institute for Social Research in Toronto we have modified our recruitment protocol to maximize contact rates. Both traditional and emerging risk factors will be identified utilizing a combination of existing and new measurement instruments. The primary outcome measurement is subclinical atherosclerosis as measured by the carotid B-Mode ultrasound. This technology allows precise quantitation of atherosclerosis and is desirable for use in population-based studies as it is not subject to reporting bias by study participants. As well, it is a continuous measurement and decreases sample size requirements. Furthermore it allows the study of the relationship of risk factors and disease across a continuum. Interesting demographic and laboratory differences were identified between the South Asians and White Canadian populations during the pilot study. Lifestyle differences in smoking and alcohol consumption, as well as socio-economic status and education were identified between the groups. As well, intriguing differences in glucose and lipid abnormalities were identified, as were differences in emerging CVD risk factors such as Lp(a) and urine microalbumin. Although extensive measures of fibrinolysis were not incorporated into the pilot study they are planned for the large study.
Few instruments to measure nutritional and psychosocial factors in nonwhite populations have been developed. The development of these instruments is outlined in this thesis proposal and. preliminary validation of these instruments has been completed as part of the SHARE pilot study. In both of these areas no “gold standard” exists against which surrogate measures may be validated and this posed unique methodologic challenges. After careful consideration of nutritional hypothesis and discussion with experts in the field of nutritional epidemiology, it was decided that a food frequency questionnaire (FFQ) would be the most appropriate instrument to identify significant qualitative differences in macronutrient consumption between ethnic populations. As no FFQ exists for South Asians, nutrient data collected from the SHARE pilot study were used to create a South Asian specific FFQ. With the initiation of the large SHARE project this FFQ will be validated against multiple 24 hour recalls taken at random. Although psychosocial factors have been repeatedly demonstrated to be associated with the development of CVD, it is extremely difficult to study these relationships precisely. There are many instruments which have be validated to measure stress and associated factors such as hostility, coping strategies and depression, yet no validation of these instruments had been conducted in the South Asian population. Therefore a SHARE Life Stress and Satisfaction Questionnaire was created after careful consideration of which stress factors may be unique to South Asians immigrants. Previously validated subscales were compiled to create this questionnaire which was completed by a subset of the SHARE pilot study participants. Validation of this questionnaire was performed on three levels content, criterion and construct. As well, reliability testing using tests of internal consistency and test-re-test reliability were conducted. Although this satisfies the criteria of validation and reliability testing of psychosocial instruments, whether or not we were attempting to measure the relevant stress factors of South Asian Canadians is questionable. In our attempt to confirm what we believed were important stressors, and to discover new factors, a qualitative substudy was designed. Using focus groups a subsample of South Asian and White Canadians will be studied and the emergent themes generated from this study will be used to develop an explanatory model of the dominant psychosocial factors and their potential relationship with health behaviours and disease status. This substudy will be run concurrently with the initiation of the SHARE project, and based on these results the Life Stress and Satisfaction questionnaire will be modified. In summary, this thesis outlines a proposal to document the prevalence of traditional and emerging risk factors and sub-clinical atherosclerosis in South Asians and White Canadians in Canada. It is our intention to follow the group identified in this cross-sectional study (Phase 1) for the progression of atherosclerosis and clinical events over time in a national cohort study (Phase 2).

abstract: Thesis

abstract: Master of Science (MS)


title: LAWA: Loss Aware Workload Assignment in Data Centers

contributor:
Down, Douglas
Badawy, Ghada
Computing and Software

abstract: Data centers are the backbone of computing, storing, processing and allowing access to large amounts of data. They consume a huge amount of energy, as of 2018, each year consuming approximately 200 TWh and this amount is only going to increase. A lot of work has been done to increase the energy efficiency of data centers. Research on reducing the power consumption of data centers has examined different levels of operations. Some of this research has proposed algorithms in lower levels such as at the device level and some in higher levels such as servers, cooling systems and workload managers. But there is no work that has considered inefficiencies in power distribution to servers (server power loss). This thesis proposes an algorithm that minimizes server power loss and then compares the resulting algorithms to those that do not consider server power loss to determine whether the resulting algorithms are consistent or not. It will be shown that the power savings of such an algorithm can be quite significant and as a result it is crucial to include such considerations when performing workload assignment.  Finally, some opportunities to continue this work in the future will be discussed.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: GRAFT - Generic Rating of Allograft Function Post Transplant

contributor:
Guyatt, Gordon
Meade, Maureen
Alba, Ana Carolina
Ross, Heather
Health Research Methodology

subject:
Transplant
Prognosis
Outcome Measurement

abstract:
Background
     Research on the optimal management of deceased organ donors poses unique challenges including the fact that one deceased donor may provide up to 8 organs for transplantation. Measuring the post-transplant function of these organs – good or bad – represents an attractive way of deciding whether treatment of deceased donors is working well, or not so well.  Function, however, is organ-specific. Therefore, to conduct the most efficient and informative research on deceased donor management, we need an outcome measure that works well in all organs.  The new outcome measure is called Generic Rating of Allograft Function post-Transplantation (GRAFT).
Methods
     In this thesis, I highlight the methods for developing the cardiac-specific version of the GRAFT instrument. The same methods, however, have and will be applied to other organ-specific versions. The work comprised various study designs and developed novel research tools, all of which have advanced the development of the GRAFT instrument. At first, we developed a simple conceptualization for the instrument. Through regular consultation with research methodologists, biostatisticians and clinical experts, we refined the fundamental conceptualization and then refined the generic instrument, itself.  One key concept is that GRAFT ratings should correlate with one-year graft function. To maximize its utility, I developed a heart--specific guide for applying GRAFT in future studies, and other organ-specific guides are underway.  Specifically, we developed these guides by identifying the most robust predictors of one-year graft function through the conduct of organ-specific systematic reviews and meta-analyses of prognostic factors. The evidence from these reviews, in consultation with a focus group of organ-specific transplant physicians, lead to refinements of our guides. We subsequently conducted a mixed-methods user testing to assess reliability and usability of the organ-specific guides. In appraising the evidence informing the guides, we developed GRADE guidance and a novel absolute risk calculator to assess our certainty in the body of evidence on prognostic factors informing our guides.
Results
     We developed a 6-point generic rating instrument for classification of graft function to be applied post-transplant across all major solid organs. We designed GRAFT to be applied at the time of discharge, 1-month post-transplant, or at the time of death (whichever occurs first). We classify function as 1) normal, 2A) impaired but likely to gain normal function, 2B) impaired and unlikely to gain normal function, 3A) severely impaired but likely to gain some function, 3B) severely impaired and unlikely to gain some function, and 4) irreversible graft failure.  Clinical expert collaborators for each organ type confirmed face validity of the GRAFT instrument.
     For all organs, we identified a number of prognostic factors that can guide users in classifying organ function post-transplant. In consultation with clinical experts, we determined that the most important factor is graft function as measured by left ventricular ejection fraction (LVEF) or right atrial pressure (RAP). Due to limitations with the quality and quantity of the evidence, however, the heart transplant experts did not rely on the results of their organ group’s systematic review. In turn, we conducted a retrospective cohort study to calculate the best estimate of association between LVEF, RAP, and overall mortality post heart transplant.
    For the cardiac version of GRAFT, user testing demonstrated high reliability (Kappa of 0.87, 95% CI 0.62 – 1.00) and acceptable usability (system usability score of 75, inter-quartile range of 72.5 – 80).
In the process, we developed and published GRADE guidance for assessing certainty in the body of evidence addressing prognostic factors and devised a calculator to transform relative effect of each prognostic factor to absolute risks (http://hiru.mcmaster.ca/AbsoluteRiskCalculator/).
Conclusion
     In this thesis, I advanced the development of an innovative generic instrument for the classification of graft function specifically for the purpose of application in clinical trials of deceased donor interventions.  This work is ongoing, but very advanced for heart-specific components, for which I have ensured face validity, and demonstrated reliability and usability. The GRAFT instrument may better facilitate the conduct of future research to improve care of deceased organ donors with a view to improving quality and quantity of organs for transplantation.

abstract: Thesis

abstract: Candidate in Philosophy


title: UNION-INDIGENOUS ENGAGEMENT IN THE MINING SECTOR

contributor:
Mills, Suzanne
Labour Studies

subject:
Union
Indigenous
Impact Benefit Agreement
Nunavik

abstract: Proponents of resource development often cite wage employment as a key benefit that Indigenous communities receive from resource development. This is based on the assumption that there is a sufficient supply of desirable employment and that job quality is high. Accordingly, provisions in Impact Benefit Agreements often focus on hiring and promotion and neglect job quality even when the latter arguably affects the desirability of mining employment. At the same time, labour unions, pivotal to improving work conditions, wages and benefits in mining, have been losing ground as global firms expand their use of subcontractors and shift to smaller, more skilled and mobile workforces. In this paper we investigate the complexity of the shifting industrial relations in Northern Canada, drawing on case studies of two mines with Impact Benefit Agreements in Nunavik: Raglan mine owned by Glencore, and Nunavik Nickel mine owned by Canadian Royalties. Drawing on document analysis and interviews with representatives from mining companies, unions and Inuit governments and organizations, this paper highlights how the complex relations among unions, companies and Inuit governments, as mediated by Impact Benefit Agreements, influence employment and job quality for Inuit workers. We propose that greater alliances between unions and Inuit governments are critical to Indigenous employment initiatives.

abstract: Thesis

abstract: Master of Arts (MA)


title: Ablation of the Somatosensory Cortex for Taste: Effects on Taste Preference and Taste Discrimination Behavior

contributor:
Morrison, G.R.
Psychology

subject:
Somatosensory Cortex
Taste discrimination

abstract: Three groups of rats were tested both before and after the bilateral ablation of the taste sensory cortex. The first group, exposed to quinine hydrochloride (QHCL) in a two-bottle preference situation, showed a large deficit postoperatively, but these were considerably reduced by the fourth postoperative week. A second group, tested for sodium chloride (NaCl) discrimination in a modified signal detection situation, also showed significant postoperative impairment. A third group, QHCL discrimination, was discarded for failure to learn the detection task. The results which were very unclear compared with NaCl discrimination and QHCL preference. It is concluded that preference tests are unsatisfactory measures of taste sensitivity unless the stimuli possess extreme aversive or preferred qualities.

abstract: Thesis

abstract: Master of Arts (MA)


title: The Influence of Trial Sequence in Discrimination Learning

contributor:
Jenkins, H.
Psychology

subject:
trial sequence
discrimination learning

abstract: This thesis presents a study of the effectiveness of a blocked series of stimulus presentations in training pigeons to perform a discrimination. It was found that this sequence of trial presentations was a least as effective as training with a random sequence of trial presentations.

abstract: Thesis

abstract: Master of Arts (MA)


title: EXPERIMENTAL ANALYSIS AND SIMULATION OF BACTERIA CHEMOTACTIC BEHAVIOR IN RESPONSE TO ANTIBACTERIALS

type: Image Thesis

contributor:
Hosseini-Doust, Zeinab
Biomedical Engineering

abstract:
Bacteria plays an important role in a great number of biological reactions in living species, such as food digestion [1] or in natural environments, such as lakes and soil [2]. As bacteria’s natural predators, bacteriophages target bacterial cells with high specificity. Co-discovered by Frederick Twort (1915) and Felix d'Hérelle (1917), bacteriophages (or for short “phage”) were used as the sole antimicrobial for treatment of infectious disease, before they were overshadowed by antibiotics in 1940 [3]. However, the rising concern over antibiotic resistance in the past decade resulted in a renewed interest towards phage antimicrobials [4].
In this study I designed microfluidic devices for studying bacteria interaction with antibiotics and viruses. Motile bacteria cells can move toward chemo-attractant or away from chemo-repellents. Hence, I quantified bacteria response to these 2 stressors in term of total displacement of cells. In addition to the experimental results, I calculated bacteria displacement for control experiment and 2 stressors by simulation of bacteria chemotaxis. Comparing the simulation and experimental results in the experiments, I identified bacteria chemotactic sensitivity, X0, that relates chemical gradient concentration to chemotactic velocity.
For future direction of this study, we suggest designing and develop a microfluidic device able to separate bacteria by exerting different drag forces to different cells. Discrepancy in the chemotactic properties of a single bacterium, such as resistance of the cell to a specific antibacterial, results in different chemotactic velocity of the cell. This distinct cell will move in a different chemotactic velocity compared to the rest of the homogenous population and hence will be exerted to a different drag force. With a proper design, different drag forces can direct cells to different chambers and hence separate cells with respect to their chemotactic response. Such a device can be used for detection of resistant bacteria to a specific antibacterial.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: The Effects of the Intensity of the Unconditioned Stimulus on the Acquisition and Extinction of the Conditioned Emotional Response

contributor:
Kamin, L.J.
Psychology

subject:
conditioned emotional response
unconditioned stimulus
acquisition
extinction

abstract:
The effects of intensity of the unconditioned stimulus (US) on the acquisition
and extinction of the conditioned emotional response (CER) in rats were investigated. The US intensities studied were 0.28, 0.49, 0.85, 1.55, and 2.91 ma. Both acquisition and extinction of the CER were found to be monotonic functions of US intensity, with the higher US intensities producing more rapid acquisition and more resistance to extinction. The lowest shock intensity failed to produce suppression. The 0.49 ma. subjects typically showed a partial recovery of normal operant behavior after development of a fairly profound CER. The results were interpreted as consistent with the supposition that the CER is acquired in accordance with Pavlovian laws
of classical conditioning.

abstract: Thesis

abstract: Master of Arts (MA)


title: MACHINABILITY ENHANCEMENT OF STAINLESS STEELS THROUGH CONTROL OF BUILT-UP EDGE FORMATION

contributor:
Veldhuis, Stephen
Mechanical Engineering

subject:
Machining performance
Stainless steel
Built-up edge
Friction
Surface texturing

abstract:
Demand for parts made from stainless steel is rapidly increasing, especially in the oil and gas industries. Stainless steel provides a number of key advantages, such as high tensile strength, toughness, and excellent corrosion resistance. However, stainless steel cutting faces some serious difficulties. At low cutting speeds, workpiece material and the chips formed during machining tend to adhere to the cutting tool surface, forming a built-up edge (BUE). The BUE is an extremely deformed piece of material which intermittently sticks to the tool at the tool-chip interface throughout the cutting test, affecting tool life and surface integrity. Unstable BUE can cause tool failure and deterioration of the workpiece. However, stable BUE formation can protect the cutting tool from further wear, improving the productivity of stainless steel machining.
This thesis presents an in-depth study of machining performance using different coated tools and various coolant conditions to examine the nature of the different tool wear mechanisms present during the turning of stainless steels. Then, different textures are generated on the tool rake face to control the stability of BUE and reduce friction during the machining process.
Results show that the BUE can significantly improve the frictional conditions and workpiece surface integrity at low cutting speeds. Finally, square textures on tool rake face were found to control the stability of BUE and minimize the friction at the tool-chip interface. This reduces the average coefficient of friction by 20-24% and flank wear by 41-78% and increases surface finish by 54-68% in comparison to an untextured tool.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Three main objectives are presented in this thesis. The first is a detailed investigation of the performance of stainless steel machining obtained by the use of different coated cutting tools and various cooling conditions. The goal of this research is to assess the reduction of tool service life, productivity, and part quality. The thesis also examines the causes of workpiece material adhesion to the cutting tool during the cutting test and to better explain its effects on tool wear and workpiece surface finish. This phenomenon is known as the "built-up edge" (BUE). Finally, different textures are applied on the cutting tool via a laser to stabilize the BUE formation on the cutting tool, thereby improving the quality of the part.


title: Improvements to the design methodology and control of semicontinuous distillation

contributor:
Adams, Thomas
Chemical Engineering

subject:
Semicontinuous Distillation
Design
Control
Dynamic Optimization
Limit Cycle
Shooting Method

abstract:
Distillation technology has been evolving for many decades for a variety of
reasons, with the most important ones being energy efficiency and cost. As
a part of the evolution, semicontinuous distillation was conceived, which has
the advantages of both batch and continuous distillation. The economic benefits
of this intensified process compared to batch and continuous distillation
were expounded in many of the previous studies. Semicontinuous distillation
of ternary mixtures, which is the main focus of this thesis, is carried out in a single
distillation column with a tightly integrated external middle vessel and the
operation is driven by a control system. The system operation does not include
any start-up or shut-down phases of the column and has three periodically repeating
operating modes.
In the status quo design procedure, called the ‘sequential design methodology,’
an imaginary continuous distillation system design was used to design the
semicontinuous distillation system. In this methodology, dynamic simulations
of the process were used to find the values of the controller tuning parameters
based on the design of the continuous system. Afterwards, black-box optimization
was used to find better controller tuning parameter values that minimized
cost. However, after analyzing the dynamics of the system for different cases,
it was found that the heuristics used in this design methodology yielded suboptimal
designs. Therefore, the primary goal of the thesis is to improve these
heuristics by incorporating more knowledge of the system and thereby develop
a better design methodology.
Firstly, the setpoint trajectories generated by the ideal side draw recovery arrangement
for side stream flowrate control, which was standard in most semicontinuous
distillation studies, was modified. In this thesis, the performance of
the status quo as compared to the modified version, based on the criteria, cycle
time and cost for different case studies, was presented. Results showed that the
modified-ideal side draw recovery arrangement for side stream flowrate control
performed better with a 10-20% lower separating cost while maintaining
product purities. Furthermore, to reap more cost benefits, dynamic optimization
was used to seek the flow rate trajectory that minimized cost. However, it
was found that the additional cost savings, which is in addition to the benefits
gained by using the modified version, were at the most 2% from different case
studies.
Subsequently, the impact of changing the imaginary continuous distillation
system design on the nature of the semicontinuous distillation limit cycle, specifically,
its period was studied. Results revealed the necessity for a new design
procedure, and thus the back-stepping design methodology was proposed. This
design methodology was used to find better limit cycles of zeotropic ternary
semicontinuous distillation using the aspenONE Engineering suite. The proposed
methodology was applied to three different case studies using feed mixtures
with different chemical components. A comparison with the sequential
design methodology for the two case studies indicates that the new method outperforms
the state-of-the-art by finding limit cycles that were 4% to 57% lower
in terms of cost. Furthermore, the designs obtained from this procedure were
guaranteed to have feasible column operation with stable periodic steady-state
behaviour.
Semicontinuous distillation design using the design methodology with heuristic
components involves guessing, checking and then using black-box optimization
to find the values of the design variables to meet some performance criteria.
Furthermore, mathematical guarantees of either local or global optimality
of the designs obtained from the design procedure do not exist. Therefore, to
address these issues, in this thesis, the application of using the shooting method
for designing the semicontinuous distillation process was demonstrated using
two case studies, which involve the separation of hexane, heptane and octane.
This method has the potential to be combined with gradient-based optimization
algorithms for optimization of the process design in the future.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Dating in the Digital Age

contributor:
Fetner, Tina
Sociology

subject:
Gender
Hookup Culture
Sexualities
University
Culture

abstract:
My dissertation examines the broader social context of hookup culture and dating in this current digital age. Data comes from a mixed-methods study that draws on original self-administered surveys (N=196) and focus groups with undergraduate women (N=21) at a university in Ontario, Canada. In this dissertation, I show that hooking up and dating coexist on campus and I examine the broader social context of hookup culture as constituted by women’s friendship groups and new technology to date and hookup. Through this research, my findings reveal how the pursuit of pleasure comes alongside many non-consensual encounters for undergraduate women. Taken as a whole, my research reveals the pleasures and perils of partying, dating, swiping, Snapchatting, and hooking up for undergraduate women.
	In Chapter Three, I draw on the descriptive statistics from my self-administered online survey and focus groups with undergraduate women to investigate whether hookup culture has emerged in a different social context without a dominating Greek culture and the role of new dating/hookup technology in this culture. In Chapter Four, I draw on the focus groups to show that hookup culture should not be understood as only about a set of expectations around sexual partners, but rather, hookup culture is heavily organized around women’s friendships with other women who support each other as they navigate the hookup scene and attempt to mitigate risks to their safety. In Chapter Five, I examine the potential of new dating apps to improve women’s dating/hookup experiences, revealing that they often fail to achieve their promises and, in other cases, they introduce new unforeseen risks to women’s safety.

abstract: Thesis

abstract: Candidate in Philosophy


title: Multimode Optical Fiber Bragg Gratings: Modeling, Simulation and Experiments

contributor:
Huang, Wei Ping
Xu, Chang Qing
Electrical and Computer Engineering

subject: multimode, fiber, bragg, grating, optical characteristics, communications, sensors, MMFBG

abstract: Telecommunication networks based on optical fiber technology have become a major information-transmission system, satisfying the growing demand for bandwidth due to increased internet traffic and other applications such as video on demand, etc. Fiber Bragg gratings (FBGs), in recent years, have emerged as critical components for enabling high-capacity transmission since their response can be tailored to meet the needs of specific applications. FBGs are currently the focus of intense research interest in both the fiber communications and sensing fields. Optical fiber Bragg grating structures in single-mode fiber (SMFBGs) have been studied extensively since the discovery of photosensitivity in germanium-doped silica fiber. They have been used in numerous applications ranging from wavelength-selective filtering in wavelength-division-multiple-access (WDMA) systems to temperature and strain sensing. To a lesser extent, Bragg gratings in multimode fibers have also received attention because of easy coupling with light sources. Most of the MMFBGs related research work has demonstrated the formation of a Bragg grating in a graded-index MMF and briefly reported the measured transmission spectrum. So far, there are few theoretical studies on Bragg gratings in multimode fibers. In this thesis, we investigate Bragg gratings in multimode optical fibers both theoretically and experimentally. A comprehensive numerical model for MMFBGs has been established and the corresponding computer simulation software (MMFBG simulator combined with mode solver) developed. The optical properties of MMFBGs were systematically studied for the first time using our own MMFBG numerical software package. It effectively assists the design modeling for MMFBG-based optical devices. Bragg gratings in multimode fiber were also investigated experimentally. Our theoretical simulation results show good agreement with experiments and offer the insightful explanations for the underlying physics of the device. First, the guided modes were modeled and simulated for step index multimode fibers and graded index multimode fibers with emphasis on parabolic fiber structure. These are popular, standard and commercially available MM fibers, and employed throughout our experiments. This allows us for the simulation of fiber characteristics such as cut-off wavelength, mode effective index, propagation constants and optical field distribution. It also allows for calculation of mode coupling coefficients by overlap integral between any chosen guided modes. Therefore, it serves as a powerful model for the design and analysis of optical fibers. Second, the generalized MMFBG coupled mode theory formalism is derived. The physical mechanism of the behavior of MMFBGs is studied and discussed. The general solution to the MMF Bragg grating problem is achieved by Runge-Kutta, Newton-Raphson and shooting numerical methods. Our theoretical treatment, in particular, offers the advantages which can deal with not only self-coupling but also more complicated cross-coupling interactions and can solve arbitrary large number of mode coupling problems throughout the entire spectra simultaneously for multimode FBGs, thus allowing for a precise and quantitative study of MMFBGs. Such an intensive multimode fiber Bragg grating physical modeling and simulations have not been reported previously. It provides an effective means for the design and analysis of optical fiber devices based on Bragg gratings. Third, the optical properties of multimode FBGs were studies experimentally. Numerical predications of the grating spectral characteristics under fabrication and experimental condition are calculated. The results of the numerical calculations are compared with experimentally measured spectra of multimode gratings written by ultraviolet irradiation of deuterium-sensitized fiber with grating reflectivities ranging from 78% to 99.39%. Good agreement is obtained between the theoretical simulations and the experimental results. Thus, we provide quantitative explanations for the observed experimental phenomena. These explanations give both physical insight and a more complete understanding of the nature of the interaction between the wave propagation and multimode fiber gratings. Furthermore, the spectral simulation of the actual experiments prepares a theoretical guidance for the advanced experimental investigation and also presents a step toward MMFBG device design. Finally, the optical properties of MMFBGs were also studied theoretically. To our knowledge, this is the first detailed analysis and thorough investigation on grating characteristics in MMF. It is demonstrated that the transmission and reflection spectra of fiber Bragg gratings in multimode optical fibers strongly depend on the length of grating, index modulation, period of grating, mode excitation condition and physical structure of MMF. The simulation results allow us to deeply comprehend and visualize the more sophisticated behavior within a multimode fiber grating, and will also allow us to confidently predict and evaluate the performance of more complex structure MMFBGs. It provides the fundamental principles for designing the targeted spectrum performance and settles the theoretical rationale for realizing the practical applications. Overall, the comprehensive numerical model and MMFBG solver package developed in this thesis opens a clear and broad window for understanding MMFBG mechanisms from the physical point of view. Various simulation results and spectral characteristics have been researched and discussed under both ideal and experimental conditions for the purpose of experimental analysis and device design. The results of our study indicate that a new class of potential applications based on MMFBGs can be expected in optical fiber sensors and advanced communication systems.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: A Comparative Electroencephalographic Study of Sleep

contributor:
Heron, Woodburn
Psychology

subject:
electroencephalographic study
sleep
EEG
EEG study

abstract:
This thesis is concerned with the variations which occur in the electroencephalograms, eye-movements, and neck-muscle potentials of three species, the pigeon, rat, and chicken during prolonged recording under normal conditions, under conditions in
which the animals were fatigued, and after drugs had been administered. While the recordings from the rat showed the two stages of deep sleep typical of animals, no distinctive ’’sleep” patterns were observed in the records from birds except after Nembutal had been given. The results seem to support the idea that birds do not sleep.

abstract: Thesis

abstract: Master of Arts (MA)


title: The Mechanical Response of an Al Alloy Reinforced with SiC

contributor:
Embury, J.D.
Materials Science and Engineering

subject:
Al Alloy
mechanical response
SiC

abstract:
This study investigated the role of Sic particles in the mechanical behaviour of a metal matrix composite (Al-SiC). Measurements of the development and magnitude of internal stresses were performed from Bauschinger experiments in the aluminum matrix A-356 reinforced with the Sic particles. The behavior of the Al matrix itself was also analyzed. The level of internal stresses in the particulate reinforced composite was found to saturate after 0.9% plastic strain and after 1.3% in the unreinforced matrix. The initial development of the unrelaxed internal stresses was analyzed using both microscopic and macroscopic models of the load-bearing role of the Sic particles.
The Sic particles were found to have little influence on the plastic flow of the composite beyond the initial plastic deformation as the size and distribution of the Sic is
very non-uniform. The effect of the Sic phase was compared to continuous fibers embedded in a metallic matrix. A model system of pure copper reinforced with continuous tungsten fibers was used for this purpose. The effect of the internal stresses on the dimensional stability of the particulate reinforced and the unreinforced
matrix was also investigated. The generation of dislocations arising from the thermal cycling of those materials was also analyzed by reference to the increase in flow stress observed after thermal cycling and from a model based on dislocations production due to the difference in coefficient of thermal expansion of the phases.

abstract: Thesis

abstract: Master of Engineering (ME)


title: Femtosecond Laser Ablation of Si, GaAs, and InP

contributor:
Haugen, Harold K.
Engineering Physics

subject:
laser ablation
Si
GaAs
InP

abstract: This thesis presents the study of x-ray emission from femtosecond laser micromachining and laser ablation of semiconductors. Prior to femtosecond machining experiments we investigated the nature of radiation emitted during the irradiation of solid targets with 120 femtosecond pulses with energies between 500 nJ and 0.3 mJ at a 1 kHz repetition rate. We have shown that the majority of the radiation was emitted below 10 keV with the high energy edge extending up to 25 keV. Under our experimental conditions K line emission was observed from materials with Z<32. We have also measured the x-ray dose rates during laser machining of various targets on the order of 10 mSv/h at a distance of 13 cm from the target. The implications for work pace safety, micromachining control, and potential for pulsed x-ray line sources for spectroscopic and imaging applications are discussed. In our studies of single shot femtosecond ablation of selected semiconductors: Si, GaAs, and InP, we have concentrated on the studies of microstructure and composition of the material after irradiation with 120 femtosecond pulses with energies between 2 nJ and 2 µJ. The resulting surface morphology, structure and composition of the micron scale ablation features on the semiconductors were studied by electron microscopy and atomic force microscopy. We found that no sharp threshold in the surface morphology was observed with increasing pulse power; however three ablation stages were identified based on the characteristic features of the ablation craters. TEM analysis revealed essentially no crystal damage beneath and in the vicinity of the ablation craters. In case of the binary semiconductors 5-30 nm polycrystalline grains were found over the ablated surfaces. The results were discussed in terms of the existing state of knowledge of ablation dynamics. The implications for practical micromachining applications are also discussed.

abstract: Thesis

abstract: Master of Engineering (ME)


title: The Use of Antisotropic Harmonic Oscillator Wave Functions in a Cylindrical Representation for Spectroscopic Calculations

contributor:
Volkov, A.B.
Physics

subject: Antisotropic harmonic oscillator

subject: wave funtion

subject: Antisotropic harmonic oscillator wave funtion

subject: spectroscopic calculations

abstract: This work is concerned with the derivation of general analytical formulae for the matrix elements, in an M representation, of effective two-nucleon interaction. The anisotropic harmonic oscillator wave equation is solved in cylindrical coordinates and the subsequent wave functions used to find the desired matrix element expressions. Since these expressions are in a form conducive to rapid machine computation this representation is well suited for spectroscopic calculations for deformed nuclei. This is illustrated by the calculation of the relative Mng energies, by means of a limited Hartree—Fock method, of several nucleonic configurations in the 2s-ld shell.

abstract: Thesis

abstract: Master of Science (MS)


title: THE EFFECT OF FLIGHT DURATION ON ß-HYDROXYBUTYRATE CONCENTRATION IN BLOOD PLASMA OF EPTESICUS FUSCUS

title: PLASMA ß-HYDROXYBUTYRATE AND FLIGHT IN EPTESICUS FUSCUS

contributor:
Faure, Paul
Gillespie, Deda
Psychology

subject:
ßeta-hydroxybutyrate
Big Brown Bat
Energetics
Metabolism
Ketone

abstract: Insectivorous bats alter relative use of metabolic substrates to match requirements of their activities, including energetically expensive flight. The “fasting while foraging” hypothesis states that the metabolic demands of flight often exceed energy intake while foraging, hence bats may metabolize fat stores (especially early in the night) to power flight with ketones, a byproduct of the normal oxidation of fatty acids. Previous studies in bats have found increases in the plasma ketone ß-hydroxybutyrate following food consumption paired with or without flight. However, no study has explored whether increases in plasma ß-hydroxybutyrate occur following flight without food consumption. We used metabolite analysis to examine changes in plasma ß-hydroxybutyrate as a function of flight duration in 2 groups (fall and spring) of captive big brown bats (Eptesicus fuscus). We fasted bats for 12 hours prior to flight (exercise treatment) or rest (control), and then collected interfemoral vein blood. Exercise activity was quantified as flight time. For the Fall group, we collected three rest samples and one flight sample. Results for the Fall group were variable; interpretation of data patterns for this group may be complicated by changes in metabolism that occur in the fall when bats physiologically prepare for hibernation. To control for seasonal effects, we tested a second group of bats in the spring, collecting two rest and three flight samples. We found a positive correlation between flight duration and levels of plasma ß-hydroxybutyrate in the Spring group, which supports the fasting while foraging hypothesis.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The “fasting while foraging” hypothesis states that the metabolic demands of flight can exceed energy intake from recently consumed prey items, so insectivorous bats may metabolize fat stores (especially early in the night) to power flight with ketones, a byproduct of the normal oxidation of fatty acids. Previous studies in bats have found increases in the plasma ketone ß-hydroxybutyrate following food consumption, but no study has explored whether increases in plasma ß-hydroxybutyrate occur following flight without food consumption. We collected and analyzed blood to examine changes in plasma ß-hydroxybutyrate following different flight durations in big brown bats. We explored both seasonal and captivity effects. To explore seasonal effects, we sampled blood from bats in the fall and the spring, times that are biologically significant to big brown bats. The spring is when bats move out of torpor, a form of hibernation, into an active state and the fall is when bats are preparing for entering into torpor. To explore captivity effects, we sampled blood from bats recently introduced to or established to captivity. Bats were fasted for 12 hours prior to flight (exercise treatment) or rest (control), and then blood was collected. We characterized exercise using flight time. We found that plasma ß-hydroxybutyrate increased after longer flight durations, which supports the fasting while foraging hypothesis.


title: Deformation of Two Phase Al-Fe and Al-Ni Alloys

contributor:
Weatherly, G.C.
Materials Science and Engineering

subject: aluminum alloys, reinforcing agent, directional solidification, fiber fracture, macrocomposite

abstract: Aluminum alloys are presently used extensively as a conductor material for overhead transmission wires. Their lack of strength must be compensated by using a reinforcing agent, namely steel. The aim of this thesis was to investigate the possibility of deforming Al-Fe and Al-Ni alloys in order to produce high strength, high conductivity wire product. The main goal was to produce a two phase Al alloy wire with adequate strength so that the wire would be self supporting as an overhead electrical power transmission line. The Al-Fe and Al-Ni two phase alloy rods were Ohno cast to provide directional solidification. In both alloys, wire drawing was unsuccessful due to fiber fracture and damage accumulation during drawing. The Al-Fe alloy was subjected to hydrostatic extrusion in an attempt to induce co-deformation of the matrix material and the brittle intermetallic second phase, Al6Fe. Hydrostatic extrusion proved to be successful in inducing some deformation of the Al6Fe and provided valuable initial insight into the investigation of the deformation of Al6Fe. The final stage in the development of an aluminum alloy for use as a self supporting overhead transmission wire was the development of a “macrocomposite”. This macrocomposite was a combination of an Fe rod 4 mm in diameter and a tube of aluminum 8 mm in diameter. This macrocomposite was successfully cold worked to achieve an overall yield strength of 395 MPa.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Determination of Two-Phase  Mass Flow Rate in Refrigerant R-134a Pipe Flow

contributor:
Shoukri, M.
Chang, J. S.
Mechanical Engineering

subject: mass flow rate, refrigerant R-134a, two-phase, pipe flow

abstract: An examination of various methods for mass flow rate measurements was undertaken to evaluate their applicability for measuring refrigerant R-134a two-phase mass flow in refrigeration and air-conditioning equipment. An experimental apparatus was constructed to generate the required two-phase flow conditions. A turbine and a venturi flowmeter were used together with either a capacitance transducer or a gamma densitometer to determine the two-phase mass flow rate. The time-averaged void fraction was measured using a capacitance transducer and a gamma densitometer. Their measurements were in good agreement. Hence, for mass flow rate measurements, the capacitance transducer was used as the void fraction meter because of its ease of operation. A number of models were used to combine the output of either the turbine flowmeter or the venturi flowmeter, with the void fraction measurement to estimate the mass flow rate. It was found that, within the range of experimental data tested in the present work, the venturi flowmeter, in conjunction with Chisholm's model, provided the best agreement with the experimental results.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Modeling of Extensional Behaviour of Polymers

contributor:
Vlachopoulos, J.
Koziey, B.
Civil Engineering

subject: modeling, extensional, behaviour, polymers, stress/strain

abstract: The use of polymeric materials in the manufacturing industry has vastly increased since the 1950’s. Because of the large amounts of material involved in modern processing operations, attempts have been made over the years to numerically simulate the processes, in the hope of optimizing operating parameters. However, in contrast to other, more traditional materials such as steel or glass, there is not a well understood connection between the microscopic structure and the (highly non-linear) macroscopic physical response of polymers. Because of this lack of microscopic cause - macroscopic effect knowledge, many descriptions of the physical response of polymers are largely phenomenological ones; that is, the equations used to model the stress/strain response make no attempt to convey information about the microscopic structure of the material.</p> <p> In the present work, five constitutive equations - Mooney-Rivlin, Ogden, G’Sell Two-term Polynomial and K-BKZ - are used to model the stress/strain response of two different polymers commonly used in thermoforming and blowmolding operations, ABS and HDPE, to uniaxial elongation and equibiaxial extension. The models are compared to experimental stress/strain data obtained from an industrial source, and the applicability of their predictions are investigated with regards to variations in strain, strain rate and temperature. Lastly, since the vast majority of real processes involve biaxial, not uniaxial, deformations, the ability of the models to predict equibiaxial response using parameters fit solely to uniaxial data is considered, in order to investigate the possibility of being able to forego the need for expensive, difficult biaxial tests.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: IMPACT OF SOCIAL ISOLATION ON MORTALITY AND MORBIDITY

contributor:
Yusuf, Salim
Health Research Methodology

subject:
social isolation
mortality
morbidity

abstract: BACKGROUND: Social isolation (SI) has been seen as an emerging socioeconomic factor that negatively affects health. A considerable body of research has found that SI is associated with increased risk of all-cause mortality. However, the magnitude of the association varies in different studies. Besides that, these studies were conducted mainly in high-income countries. METHODS: We conducted a systematic review and meta-analysis to examine the effect size of SI on mortality. Also, we examined the associated mortality risk using data from the Prospective Urban and Rural Epidemiology (PURE) study of over 140,000 middle-aged adults from 21 countries with different income levels. RESULTS: Our systematic review and meta-analysis showed that the pooled hazard ratio of SI for all-cause mortality was 1.37 (95% confidence interval (CI) 1.28-1.46). The PURE study showed that the hazard ratio of SI for all-cause mortality was 1.26 (95% CI 1.16-1.36). Similar associations of SI with cardiovascular- and non-cardiovascular mortality as well as with incident diseases including stroke, cardiovascular disease, and injury were observed. The associations between SI and health outcomes were observed in diverse populations with different social structures and different country income levels. CLINICAL IMPLICATIONS: The impact of SI on mortality would be expected to be greater in the future as the number of people with SI is projected to increase with population ageing in most societies. Our findings can be used by public health providers and policy makers to develop targeted strategies to reduce the risks associated with SI.

abstract: Thesis

abstract: Master of Health Sciences (MSc)

abstract: Social isolation (SI) is an emerging socioeconomic factor that could negatively affect health. Prior studies regarding SI were conducted mainly in high income countries. This thesis examines the effect of SI on mortality. This was done first in a systematic review and meta-analysis and, second, by examining the association between SI and health in an international large-scale cohort study (PURE: Prospective Urban Rural Epidemiology) conducted in 21 countries at different country income levels. Our systematic review and meta-analysis showed that SI was associated with 37% increased risk for mortality. The PURE study showed that the association of SI with mortality was seen in diverse populations with different social structures. The impact of SI on mortality would be expected to increase in the future as the number of people with SI is projected to increase with population ageing. This calls for measures to reduce mortality and morbidity in the socially isolated.


title: A Model-Based Approach to Formal Assurance Cases

contributor:
Wassyng, Alan
Lawford, Mark
Computing and Software

subject:
Safety Assurance
Software Engineering

abstract:
The rapidly increasing complexity of safety-critical embedded systems has been
the cause of difficulty in assuring the safety of safety-critical embedded systems
and managing their documentation. More specifically, current approaches to
safety assurance are struggling to keep up with the complex relationships be-
tween the ever growing number of components and the sheer amount of code
underlying safety-critical embedded systems such as road vehicles. We believe
that an approach to safety assurance able to cope with this complexity must: i)
have sound mathematical foundations on which safety assurance can be built;
and ii) provide a formal framework with precisely defined semantics in which
the assurance can be represented. In doing this, assurance can be made less
ad-hoc, more precise and more repeatable. Sound mathematical foundations
also facilitate the creation of tools that automate many aspects of assurance,
which will be invaluable in coping with the complexity of modern-day and
future embedded systems. The model-based framework that achieves this is
+
Workflow . This framework is rigorous, developed on proven notations from model-based methodologies, comprehensively integrates assurance within the development activities, and provides the basis for more formal assurance cases.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Restoring Consistency in Ontological Multidimensional Data Models via Weighted Repairs

contributor:
Chiang, Fei
Computing and Software

subject:
Logic
Data Science
Data Cleaning
MCDM
CRITIC
OMD
Genetic Algorithms
Database
Datalog

abstract: This can be considered as a multidisciplinary research where ideas from Operations Research, Data Science and Logic came together to solve an inconsistency handling problem in a special type of ontology.

abstract:
High data quality is a prerequisite for accurate data analysis. However, data inconsistencies
often arise in real data, leading to untrusted decision making downstream in the data
analysis pipeline. In this research, we study the problem of inconsistency detection and
repair of the Ontology Multi-dimensional Data Model (OMD). We propose a framework
of data quality assessment, and repair for the OMD. We formally define a weight-based
repair-by-deletion semantics, and present an automatic weight generation mechanism
that considers multiple input criteria. Our methods are rooted in multi-criteria decision
making that consider the correlation, contrast, and conflict that may exist among
multiple criteria, and is often needed in the data cleaning domain. After weight generation
we present a dynamic programming based Min-Sum algorithm to identify minimal
weight solution. We then apply evolutionary optimization techniques and demonstrate
improved performance using medical datasets, making it realizable in practice.

abstract: Thesis

abstract: Master of Computer Science (MCS)

abstract: Accurate data analysis requires high quality data as input. In this research, we study inconsistency in an ontology known as Ontology Multi-dimensional Data (OMD) Model and propose algorithms to repair them based on their automatically generated relative weights. We proposed two techniques to restore consistency, one provides optimal results but takes longer time compared to the other one, which produces sub-optimal results but fast enough for practical purposes, shown with experiments on datasets.


title: A PROCESS MONITORING EVALUATION OF A NURSE-LED REMOTE AUTOMATED MONITORING AND VIRTUAL CARE INTERVENTION

contributor:
McGillion, Michael
Nursing

subject:
Postoperative monitoring
Remote Automated Monitoring
Cardiac Surgery
Virtual Hospital-to-Home Care
Nurse leadership
Process monitoring evaluation

abstract:
Clinical trials involving digital health technologies are complex and challenging deployments. The SMArTVIEW trial (n=800), underway, combines remote automated patient monitoring (RAM) in hospital and virtual hospital-to-home nursing support, up to 30-days post-discharge, for patients who have undergone cardiac and major vascular surgery. Cardiac and vascular surgery patients are at risk for postoperative complications, as well as hospital readmission; SMArTVIEW aims to reduce hospital readmissions and emergency department visits. The purpose of this work was to conduct a process monitoring evaluation of the first 100 patients enrolled in order to examine the implementation, mechanisms, context, and specialized nursing role of the SMArTVIEW intervention.
Six data sources were used to examine patient recruitment, daily nursing intervention workflows, RAM technology compliance, technical troubleshooting, patient education, and virtual nursing care. A content analysis was used to identify nursing advice, recommendations, and corrective actions for patients requiring intervention recovering at home.
 Fifty patients were allocated to the SMArTVIEW intervention; of these, 34 engaged in all intervention components, both in-hospital and at home. In-hospital RAM technology generated 194 notifications, drawing nurses to the beside for patient reassessment. Forty-two daily nurse reports and 926 virtual nursing care records were audited to determine technology implementation issues and nursing actions to support patient recovery at home. Process monitoring uncovered strengths and limitations in the initial days of intervention deployment. Strengths included the functionality of RAM technology, facilitating nurse compliance with required workflows, as well as a high degree of patient engagement in the program. SMArTVIEW nurses addressed multiple health concerns for patients, resulting in 1,865 nursing actions over the 30-day intervention course. Patient withdrawals and lack of standardized communication practices were areas requiring improvement. Results were used to refine and standardize intervention workflows in order to scale the intervention for deployment at a second site (United Kingdom).

abstract: Thesis

abstract: Master of Science (MSc)


title: Optimising Musculoskeletal Health: Focus on Exercise Therapy and Psychosocial Interventions

contributor:
MacDermid, Joy
Grewal, Ruby
Macedo, Luciana
Szekeres, Mike
Rehabilitation Science

subject:
Therapeutic Exercise
Psychosocial Intervention
Adherence
Musculoskeletal
Behavior
Web-based Interventions

abstract:
Musculoskeletal disorders are a considerable burden to the individual and the society at large. Therapeutic exercise and psychosocial interventions are longer-term therapies for relieving pain, improving function and outcomes after musculoskeletal disorders, and for enabling patients to manage their conditions. Healthcare professionals such as physiotherapists and occupational therapists widely use therapeutic exercise as part of a single or complex intervention. However, adherence to supervised or home exercise remains low among patients with musculoskeletal disorders. Understanding the barriers and facilitators of exercise adherence has the potential to improve the delivery of exercise programs and the design of interventions to improve adherence.
Similarly, psychosocial interventions are recommended as a supplement to exercise therapy for the management of prolonged pain and disability after musculoskeletal disorders. Several psychosocial factors have been linked to prolonged pain and disability after hand injuries. However, while clinicians believe they have a role in managing psychosocial problems in hand therapy, barriers such as limited access and lack of knowledge pose a challenge to delivering psychosocial interventions. Current evidence shows that online-based coping skill programs provide cost-effective and accessible options for delivering psychosocial interventions in musculoskeletal care. However, there is a dearth of literature on the design, development, and implementation of online-based psychosocial interventions in hand therapy.
This thesis includes four manuscripts with three overarching objectives. The first objective was to synthesize the qualitative evidence on barriers and facilitators of therapeutic exercise towards closing the gaps in adherence literature. The second objective was to understand the beliefs, attitude, knowledge and practice behavior of clinicians with regarding to managing psychosocial problems in hand therapy. The third objective was to provide a report on the design and development of a web-based coping skill training program for psychosocial problems specific to hand therapy. The fundamental aim is to provide toolkits that can be used to increase the knowledge and clinical practice behavior of physiotherapists and occupational therapists to optimize musculoskeletal health using therapeutic exercise and psychosocial interventions.
The second and third manuscripts are a protocol and completed meta-synthesis of qualitative literature outlining the factors influencing adherence to therapeutic exercise in individuals with musculoskeletal disorders from the perspective of patients and healthcare professionals. We identified numerous factors influencing adherence to therapeutic exercise, which were organized according to the World Health Organization (WHO) multidimensional adherence framework. Based on the meta-ethnography line of argument, interpretation of identified themes: personal and lifestyle characteristics, health status and illness perception, nature of the program, health system, and social/environmental resources, showed that while some factors interact, others could be conceptualized as being on a continuum. These findings expanded the original model introduced by the WHO.
The fourth manuscript presents a qualitative descriptive study designed to understand the knowledge, attitude, beliefs, and practice behavior of hand therapists practicing in Ontario with regards to psychosocial problems. The findings informed by the Theoretical Domains Framework provide insights into factors influencing the decision of clinicians to assess and manage psychosocial interventions in hand therapy. Addressing factors such as knowledge, attitudes, and beliefs about psychosocial factors at the individual and organizational level has the potential to increase the capacity of clinicians to adopt a clinical practice behavior that promotes the assessment and management of psychosocial problems in hand therapy.
The fifth manuscript is a mixed-methods study describing the design, development, and usability testing of Hand Therapy Online COping Skills (HOCOS) training online program to support hand therapists in the management of psychosocial problems. Using a three-step process that involved needs assessment, heuristic testing, and user testing, we sought feedback from Information and Communication Technology experts and clinicians in hand therapy to develop the HOCOS prototype using iterative cycles. The results revealed heuristic violations and usability related to task performance, navigation, design aesthetics, content, functionality, and features and desire for future use. All violations were corrected in the final prototype, and participants expressed a high degree of satisfaction with using the final prototype in practice. The next phase of HOCOS design would require user testing by patients with hand injuries.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract:
Bone and joint injuries are very common in orthopedic practice and massive burden to individuals and society at large. Many patients are given exercises as part of their treatment to reduce pain and improve function. Unfortunately, many individuals continue to struggle with attending therapy sessions and doing exercises by themselves. Starting and continuing exercises are required to maximize the benefits from exercise recommendations. However, many barriers continue to make exercising a challenge. Research is needed to identify the challenges of starting and continuing exercises from the perspectives of both patients and healthcare professionals.
In some situations, some patients with bone and joint injuries such as hand injuries continue to have pain and reduced function even after the original injury has healed. The weak relationship between the initial injury and present experience of pain and reduced function means other reasons like the mental, emotional, and social factors need to be considered in clinical practice. Healthcare professionals have reported several difficulties when dealing with psychosocial problems and want to learn strategies and skills for dealing with the mental, emotional, and social challenges affecting recovery after injuries to bones and joints. The use of the web-based coping skills training for managing psychosocial problems in individuals with bone and joint conditions has shown positive results. However, these strategies are yet to be explored in individuals with injuries to the hand and upper limb.
This thesis includes four papers with the first two papers aimed at examining the literature on adherence to therapeutic exercise. Findings from these papers showed the interactions among the five factors influencing adherence to exercise according to the World Health Organization’s model: patient, health condition, treatment plan, health system, and socioeconomic factors. The third paper sought to understand the opinion of clinicians working in hand therapy about the mental, emotional, and social issues of patients. The result showed that participant’s beliefs, attitudes, knowledge and behavior concerning the assessment and management of psychosocial issues are shaped by several factors organized into six themes. The final paper reports on the steps involved in the making of a new internet coping skill program developed for use in individuals with hand and upper limb conditions. Review of the website by technology experts and clinicians showed areas for improvement which were subsequently amended until the participants reported satisfaction with the system. The clinicians expressed interest in using the online coping skill program in their hand therapy practice.


title: DISABILITY EXPERIENCED BY SOUTH ASIAN WOMEN LIVING WITH HIV IN SOUTHERN ONTARIO

contributor:
Solomon, Patricia
Moll, Sandra
O'Brien, Kelly
Rehabilitation Science

subject:
South Asian
women
disability
phenomenology
HIV/AIDS

abstract:
Purpose: In Ontario, there is a steady rise in the HIV incidence among South Asian women. However, the health-related challenges and the disability experienced by this population are under reported. Hence, this study aims to understand the disability experience and utilization of rehabilitation services by the South Asian women living with HIV in Southern Ontario, Canada.
Method:  I used an interpretive phenomenological study design to explore the ‘lived experience’ and ‘meaning’ of disability experienced by South Asian women living with HIV. I recruited English-speaking immigrant South Asian women living with HIV through the Alliance for South Asian AIDS Prevention (ASAAP). I conducted in depth face to face interviews using body mapping and photo-elicitation techniques. All the interviews were transcribed verbatim and a thematic analysis approach was utilized to understand the disability experiences and rehabilitation needs of the women.
Findings: Eight women volunteered for this study with six agreeing to be interviewed on a second occasion.  The mean age was 47.1 years (s.d=5.8), and mean length of time since HIV diagnosis was 15.1 years (s.d=6.7).  Analysis resulted in four major themes: “experiencing disability”, “building resilience”, “experiencing discrimination” and “accessing health care”. The women described several health challenges due to the side effects of anti-retroviral medications, compounded by challenges associated with immigration, HIV stigma, and discrimination. The complex intersection of illness, gender, ethnicity, and discrimination affected their overall disability experience. Despite these challenges, the women manifested resilience by re-constructing their identities, specifically by exhibiting perseverance in the midst of their health challenges, isolation, and patriarchal culture. Women lacked understanding about rehabilitation services in the context of HIV.
Conclusion: This study draws attention to marginalized women living with HIV whose voices are rarely heard, and profiles their experiences of disability. Understanding the disability needs of marginalized women living with HIV, through a phenomenological lens could help to facilitate the development of culturally safe treatment approaches and health care policies, which can lessen their disability and improve their quality of life.

abstract: Thesis

abstract: Doctor of Science  (PhD)