title: Hydrogeological and Ecohydrological Controls on Peatland Resilience to Wildfire

contributor:
Waddington, James Michael
Geography and Earth Sciences

subject: peatland, wildfire, wetland, carbon, resilience, hydrology, hydrogeology, ecohydrology

abstract:
Peatlands represent a globally significant carbon stock and wildfire is the largest disturbance affecting these ecosystems. Climate change scenarios suggest that increases in evapotranspiration are likely to exceed increases in precipitation in northern latitudes, raising concern that peatlands will experience substantial drying. Drying may increase peat burn severity and, when coupled with expected increases in total wildfire area burned, may exceed peatland resilience to wildfire. While previous studies have examined both peatland vulnerability to wildfire and post-fire recovery, these studies have not examined the driest peatlands on the landscape that are likely to be the most susceptible to the combined effects of climate change and wildfire. For this reason, this thesis examined the hydrogeological and ecohydrological controls on burn severity and post-fire recovery in peatlands in the Boreal Plains of Alberta, where peatlands exist at the limit of their climate tolerance.
	High burn severity was prevalent at the margins of a small peatland isolated from groundwater flow, where average burn depths were five-fold greater than in the middle of the peatland. Deep burning was attributable to the effect of dynamic hydrological conditions on margin peat bulk density and moisture. Following wildfire, water availability was a key determinant of post-fire moss recovery. Both high and low burn severity can decrease post-fire water availability by altering peat hydrophysical properties. Post-fire recovery was also dependent on large-scale hydrological processes that influence peatland water tables, specifically, hydrogeological setting. Small peatlands isolated from groundwater flow systems had lower peatland moss recolonization rates at both their middles and margins due to drier conditions. This was important because the margins of these same peatlands were prone to deep burning. Therefore, deep burning is likely altering peatland margin ecohydrological function and may be facilitating a regime shift from peatland to mineral upland.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: CHILDREN OF PARENTS DIAGNOSED WITH BIPOLAR DISORDER: AN INVESTIGATION OF THE BEHAVIOURAL, STRUCTURAL AND FUNCTIONAL CORRELATES OF RISK

title: NEURAL CORRELATES OF RISK  IN CHILDREN OF PARENTS WITH BIPOLAR DISORDER

contributor:
HALL, Geoff
SASSI, Roberto
Neuroscience

subject:
BIPOLAR DISORDER
NEUROIMAGING
BIOMARKERS
HIGH-RISK OFFSPRING

abstract:
Emotion processing and regulatory deficits have been well established in individuals diagnosed with bipolar disorder (BD). Both structural and functional neural deficits have been associated with the presence of psychiatric symptoms in BD. In Chapter 2, we reviewed cortical thickness deficits found in patients with BD. It is unclear however, how early these deficits appear; whether they contribute to risk, or whether these deficits develop as a consequence of the onset of symptoms.

To address this, many researchers have turned to high-risk offspring populations. These high-risk offspring are at much greater risk of developing BD by virtue of having a parent diagnosed with BD. Moreover, the presence of anxiety, depression or ADHD related symptoms in this population suggest these children are at even greater risk to develop BD. By comparing high-risk offspring with and without the symptoms can help to elicudate neural correlates associated with risk and resilience for BD. It was the aim of this thesis research to investigate the behavioural, structural and functional correlates of risk.  Specifically, presented in this thesis, we compared the gray matter integrity, through volume (Chapter 3) and cortical thickness (Chapter 4) techniques, in symptomatic and asymptomatic high-risk offspring to healthy children of healthy parents. We also compared the ability of these offspring to perform an emotion-labelling task (Chapter 5) and engage in emotional conflict monitoring and conflict adaptation during an fMRI scan (Chapter 6).

Altogether, our results provide evidence for the presence of gray matter volume, emotion labelling, and conflict monitoring and conflict adaptation functional deficits in high-risk offspring compared to healthy children of healthy parents. With the exception of cortical thickness, we found that the deficits between symptomatic and asymptomatic high-risk offspring were comparable. This suggests that behavioural, structural and functional deficits may reflect neural correlates of risk and are not associated with the presence of symptoms.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The vocal-motor system of the human brain

contributor:
Brown, Steven
Psychology

subject:
voice
larynx
brain
fMRI
motor system
meta-analysis

abstract: The larynx is the mammalian organ of vocalization. Humans have a degree of control over this organ considerably beyond the abilities of other primates, most notably in our control over the larynx during speech. Although there is an abundance of research on the neural basis of speech, relatively little of this research has focused on the control of the larynx. First, I performed a meta-analysis to search for brain areas responsible for making explicit judgments about affective prosody to identify candidate premotor areas in prefrontal cortex that may also plan the affective component of affective prosody (Chapter 2). The inferior frontal gyrus pars orbitalis was the only prefrontal region preferentially engaged by affective vocalizations. Second, I used functional magnetic resonance imaging to determine whether there are discrete neural systems for producing innate-affective versus arbitrary non-affective vocalizations in the human brain, as has been predicted from non-human primate models (Chapter 3). The vocal-motor system demonstrated a lack of specialization since both types of vocalizations engaged the entire network. Third, I searched for brain areas that were preferentially engaged during vocal imitation (Chapter 4), which is a key process in vocal learning. Vocal imitation preferentially engaged a cortico-striate network similar to that predicted from avian models of vocal imitation. Finally, I performed a meta-analysis to explore the neural basis of persistent developmental stuttering (Chapter 5), a speech disorder that is associated with poor control of the laryngeal muscles. Among other brain areas, primary motor regions controlling the larynx were abnormally activated in the brains of people who stutter. Together these studies advance our knowledge of the human vocal-motor system, how it relates to that in other species, and how this system may be disrupted in persistent developmental stuttering. I discuss remaining gaps in our knowledge that will be the focus of my future research.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: One hallmark of the human species is our ability to talk. This dissertation describes a body of research that uses modern brain imaging technology ¬to study the brain systems that underlie this ability in humans –referred to as the vocal-motor system. It then compares this system in humans to the closest equivalent in monkeys, since monkeys lack this ability but share relatively recent common ancestry with humans. It also makes comparisons with the brains of songbirds, since the ability of juvenile songbirds to learn songs may share similarities with the human ability to learn speech. Finally, it looks at the potential dysfunction of this system in the brains of people who stutter.


title: Quantitative Near-Field Microwave Holography

contributor:
Nikolova, Natalia
Electrical and Computer Engineering

subject:
holography
image processing
microwaves
calibration
reconstruction algorithms
quantitative imaging

abstract:
This thesis presents two quantitative holographic reconstruction techniques for the imaging of dielectric targets. The first method is a quasi-real-time holographic reconstruction technique, which is capable of imposing physically based constraints on the real and imaginary parts of the permittivity. The other method is a real-time holographic reconstruction technique that is faster than the constrained method but cannot accommodate constraints on the reconstructed permittivity in its current form. The goal of this thesis is to introduce both methods and recommend which is best.
Microwave holography has been used by our research group to reconstruct images of a target’s shape and location from microwave scattering parameters. This thesis will demonstrate that holography can be extended to quantify the permittivity distribution in a region of interest.
The problems presented in this thesis are generic and are meant to show that near-field quantitative holography is a valid approach for applications such as tissue imaging, baggage inspection, concealed weapon detection, etc.
The holographic inversion is carried out in the spectral domain (Fourier space), which allows for the use of Fourier transform properties to expedite the algorithm. This differs from sensitivity-based imaging (another inversion method developed by Tu et al. (2015)) where the inversion is performed in real space and is unable to take advantage of the techniques proposed in this thesis to improve the speed of reconstruction.
Mutual coupling is not taken into consideration in the forward model of scattering used here; however, this technique is meant to be viewed as a foundation for a more sophisticated reconstruction algorithm, like the iterative Born method, which can overcome such limitations. Iterative reconstruction methods require an accurate initial guess, which can be provided by the quantitative technique presented in this thesis.
Moreover, this technique, implementing fast and efficient linearized inversion, can serve as a module, which is called repetitively by the iterative algorithm. Such a module will take the current estimate of the total field distribution inside the imaged volume as an input and will return an estimate of complex permittivity distribution.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Remaking the Mould: Scriptural Types and Anglo-Saxon Heroes in "The Dream of the Rood," "Elene," and "Judith"

contributor:
Savage, Anne
English and Cultural Studies

subject: Dream of the Rood, Elene, Judith, Heroism, Gender

abstract:
My thesis explores the cultural and gender syncretic processes of Old English literature in three Anglo-Saxon poems: The Dream of the Rood, Elene, and Judith.  Throughout my research I attempt to answer the question of syncretism as it is applied to Anglo-Saxon concepts of heroes and heroism in literature.  While Old English scholars (including John M. Hill, Hugh Magennis, and Jane Chance) have developed this line of inquiry previously, my work pushes back on several assumptions that hinder their analyses.  In particular, I resist the tendency of late 20th-century criticism to dichotomize the Germanic and Christian aspects of the texts, contending that since Latin Christianity was completely indigenized over a hundred years prior to the writing of these poems, it is impossible to discern a pre-Christian set of values and social norms.  Instead, I discuss the converging influences of monastic and secular aspects of Anglo-Saxon in relation to the literary hero.
	I also examine the complex gender dynamics and performances that manifest in these three poems, arguing that the triumphant hero or heroine is able to succeed through a wide-ranging set of both masculine and feminine performances.  Here I incorporate a subtle commentary of gender theory — especially Judith Butler’s theory of performativity — to complement my own textual criticism.  As this sort of gender syncretism meets with the culturally syncretic writings of the Anglo-Saxon poets, a new and idealized type of hero emerges, one who accomplishes victory through both spiritual and secular, as well and masculine and feminine performances.

abstract: Thesis

abstract: Master of Arts (MA)

abstract: This thesis aims to discuss the process and purposes of “remaking” the Anglo-Saxon hero in three Anglo-Saxon poems: The Dream of the Rood, Elene, and Judith.  I examine how the poets blend various monastic and secular influences within Christianized Anglo-Saxon culture in order to establish a new and ideal literary hero, one who often resembles spiritual archetypes such as Christ or the Virgin Mary.  I also explore the complex gender dynamics that emerge in these poems, and in particular how the protagonist — the hero or heroine — navigates a diverse range of both masculine and feminine performances in order to succeed.


title: Empresses, Bhikṣuṇīs, and Women of Pure Faith: Buddhism and the Politics of Patronage in the Northern Wei

contributor:
Benn, James
Religious Studies

subject:
Buddhism
Chinese Religions
Northern Wei
Women

abstract: This dissertation is a study of the contributions that women made to the early development of Chinese Buddhism during the Northern Wei Dynasty 北魏 (386–534 CE). Working with the premise that Buddhism was patronized as a necessary, secondary arm of government during the Northern Wei, the argument put forth in this dissertation is that women were uniquely situated to play central roles in the development, expansion, and policing of this particular form of state-sponsored Buddhism due to their already high status as a religious elite in Northern Wei society. Furthermore, in acting as representatives and arbiters of this state-sponsored Buddhism, women of the Northern Wei not only significantly contributed to the spread of Buddhism throughout East Asia, but also, in so doing, they themselves gained increased social mobility and enhanced social status through their affiliation with the new, foreign, and wildly popular Buddhist tradition. Throughout the dissertation, stories of empresses, concubines, female bureaucrats, lay devotees, and female members of the Buddhist monastic institution will be studied in order to show the unique connections between women and the Buddhist tradition under the Northern Wei and also to reveal the diversity of roles that they played in the administration of a court-sponsored, imperial Buddhist tradition. In bringing these stories to light, this dissertation will utilize biographical material from the dynastic history of the Northern Wei as well as from a number of previously unstudied epigraphs. Additionally, other forms of inscriptional, religious, and secular materials will be widely consulted in this exploration of the lives of Buddhist women at a time when Buddhism was becoming a state religion in a powerful and ambitious dynasty – the Northern Wei.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: UNDERSTANDING HOW NURSES EXPERIENCE LIVING THEIR VALUES AMIDST ORGANIZATIONAL CHANGE: A NARRATIVE INQUIRY

contributor:
Landeen, Janet
Nursing

subject:
Narrative Inquiry
nursing voice
nursing values
organizational change

abstract:
Abstract
Values are foundational guidelines that underpin nurses’ actions. They serve as fundamental points of reference for nurses; and, as such, determine their moral nursing practice. Understanding how nurses’ experience of living their values amidst organizational change sheds light on how this social condition influences the narrative composition of nurses’ lives and their practice. This Narrative Inquiry (Clandinin & Connelly, 2000) illuminates the temporal connections of life events; how social conditions mutually shape personal conditions; and how actions that occur within a place give meaning to the experience. Six nurses from a large academic health centre in Southern Ontario were recruited and interviewed over eight months. During initial analysis, letters were constructed for each co-participant to reveal the experience of living values amidst organizational change. Subsequently, a composite narrative in the form of a letter was composed, revealing four plotlines: responsive relationship, moral distress, reflection and reconstruction, and knowledge and identity. These plotlines intersect to describe the extent to which nurses meet their moral obligations within relational practice. This inquiry brings to the foreground four narrative terms, including stories to commit by, that contribute to a new way of thinking about familiar issues. It illuminates the personal and the active movement of reflection that reside in a person and the choice(s) she/he makes to re-craft a life. Considerations for practice, education, policy, and research highlight the importance of a deeper level of reflective practice, the connection between personal and ethical knowledge, and the need for becoming aware of one’s moral horizon.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: EVALUATION OF THE RELATIONSHIP BETWEEN CAROTID PERIVASCULAR ADIPOSE TISSUE AND ARTERIAL HEALTH

contributor:
MacDonald, Maureen
Kinesiology

subject: Perivascular adipose tissue, Arterial Stiffness, Carotid IMT, Carotid EMT, Carotid Distensibility, CAD

abstract: Perivascular adipose (PVAT) has been hypothesized to influence arterial health, where an excess can lead to pathogenesis of atherosclerosis and other arterial pathologies. A novel assessment of carotid PVAT is the use of carotid extra media thickness (EMT) ultrasonography. Currently, there is a lack of research to demonstrate the relationship between carotid EMT and existing measures of arterial health, notably, central pulse wave velocity, and carotid distensibility and intimal media thickness. In the current cross sectional study, 81 participants of younger recreationally active (ages 23.2 ± 2.5 years), younger sedentary (ages 26.4 ± 7.2 years), older healthy (ages 70.3 ± 5.4 years) and older adults with coronary artery disease (CAD) (ages 67.9 ± 8.7 years) were recruited. Resting measures of central arterial stiffness was examined through the assessment of aPWV, while measures of local carotid stiffness were examined through carotid distensibility. Aortic PWV was calculated using an accepted direct distance method (80% of carotid to femoral direct distance) and time difference between the feet of the carotid and femoral waveforms.  Carotid intima-media thickness (IMT), a measure of the inner arterial walls, and carotid extra media thickness (EMT), a measure of carotid PVAT, were assessed through B-mode ultrasound images and a semi-automated edge tracking software. Carotid EMT, IMT, and aPWV were significantly greater in older adults than in younger adults (p < 0.05). No difference in carotid EMT was found between younger recreationally active (0.47 ± .08 mm) and sedentary adults (0.46 ± .06 mm). There were also no differences in carotid EMT between the older healthy (0.58 ± .06 mm) and older adults with CAD (0.54 ± 0.08 mm). Carotid EMT was also significantly correlated with age (r =0 .500), waist circumference (r = 0.521), aPWV (r =0.431), carotid distensibility (r = -0.364 and IMT (r = 0.404). Despite significant correlations, carotid EMT was not an independent predictor of aPWV, carotid distensibility and IMT. Because of the lack of predictive power in measures of arterial stiffness and carotid IMT, there is a potential that carotid EMT may be an independent vascular disease marker. Future investigations should involve carotid EMT in longitudinal studies to evaluate the potential marker for a more comprehensive cardiovascular risk assessment.

abstract: Thesis

abstract: Master of Science (MSc)


title: ANTERIOR SEGMENT DYSGENESIS AND GLAUCOMATOUS FEATURES OBSERVED FOLLOWING CONDITIONAL DELETION OF AP-2β IN THE NEURAL CREST CELL POPULATION

title: AP-2β IN THE DEVELOPMENT OF THE ANTERIOR SEGMENT OF THE EYE

contributor:
West-Mays, Judith
Medical Sciences

subject:
Eye Development
Glaucoma
Transcription Factors
AP-2B
Anterior Segment Dysgenesis
Conditional Deletion
Mouse Model
Cre LoxP
Neural Crest Cells

abstract:
Glaucoma is a heterogeneous group of diseases that is currently considered to be the leading cause of irreversible blindness worldwide. Of the identified risk factors, elevated intraocular pressure remains the only modifiable risk factor that can be targeted clinically. Ocular hypertension is often a result of dysregulation of aqueous humour fluid dynamics in the anterior eye segment.
Aqueous humour drainage is regulated by structures located in the anterior chamber of the eye. In some circumstances dysregulation occurs due to developmental abnormalities of these structures. The malformation of structures in the anterior segment is thought to be due to a defect in the differentiation and/or migration of the periocular mesenchyme during development. Unique to vertebrates, the neural crest cell (NCC) population contributes to the periocular mesenchyme and is instrumental to the proper development of structures in the anterior segment.
For many years our laboratory has examined the role of the Activating Protein-2 (AP-2) transcription factors that are expressed in the neural crest and vital during the development of the eye. The purpose of this research project is to investigate the role of AP-2β in the NCC population during the development of the anterior segment of the eye.
Conditional deletion of AP-2β expression in the NCC population demonstrated that mutants have dysgenesis of structures in the anterior segment including defects of the corneal endothelium, corneal stroma, ciliary body and a closed iridocorneal angle. Loss of retinal ganglion cells and their axons was also observed, likely due to the disruption of aqueous outflow, suggesting the development of glaucoma.
The data generated from this research project will be critical in elucidating the role of AP-2β in the genetic cascade dictating the development of the anterior eye segment in addition to providing scientific research with a novel model of glaucomatous optic neuropathy.

abstract: Thesis

abstract: Master of Science (MSc)


title: Notions of Semicomputability in Topological Algebras over the Reals

contributor:
Zucker, Jeffery
Computing and Software

subject:
Generalised computability theory
Computability theory
Computability on the reals

abstract:
Several results from classical computability theory (computability over discrete structures such as the natural numbers and strings over finite alphabets, due to Turing, Church, Kleene and others) have been shown to hold for a generalisation of computability theory over total abstract algebras, using for instance the model of \While\ computation.

We present a number of results relating to computation on topological partial algebras, again using \While\ computation. We consider several results from the classical theory in the context of topological algebra of the reals: closure of semicomputable sets under finite union (Chapter \ref{chap:results1} Theorem \ref{thm:union_While_scomp_not_While_scomp}, p.\pageref{thm:union_While_scomp_not_While_scomp}), the equivalence of semicomputable and projectively (semi)computable sets (Chapter \ref{chap:results2} Theorem \ref{thm:proj_while_equivalents}, p.\pageref{thm:proj_while_equivalents}), and Post's Theorem (i.e.~a set is computable iff both it and its complement are semicomputable) (Appendix \ref{appendix:posts_theorem} Theorem \ref{thm:posts_general}, p.\pageref{thm:posts_general}).

This research has significance in the field of scientific computation, which is underpinned by computability on the real numbers. We will consider a ``continuity principle", which states that computability should imply continuity; however, equality, order, and other total boolean-valued functions on the reals are clearly discontinuous. As we want these functions to be basic for the algebras under consideration, we resolve this incompatibility by redefining such functions to be partial, leading us to consider topological partial algebras.

abstract: Thesis

abstract: Master of Computer Science (MCS)

abstract: We investigate to what extent certain well-known results of classical computability theory on the natural numbers hold in the context of generalised computability theories on the real numbers.


title: The Grand Strategy of the Ottoman Empire, 1826-1841

contributor:
Aksan, Virginia H.
History

subject:
Ottoman Empire
Grand Strategy
19th Century
Ottoman Political Thought
Ottoman Social and Political History
Ottoman Governance
Ottoman Warfare

abstract:
This dissertation examines the Ottoman grand strategy during the turbulent years of war and reform between 1826 and 1841.The concept of grand strategy utilized in my thesis does hereby not refer to purely military matters. It is rather a notion that explains how a political authority strives to realize its long-term aims through mobilization of its available instruments and resources. During 1820s-1840s, facing grave internal and external threats, the Ottoman grand strategy was directed at defending its existing possessions and re-establishing the center’s authority throughout the empire. To ensure their aims, Ottoman decision-makers initiated a radical bureaucratic-military reform agenda and mobilized available fiscal, military and ideological resources at their disposal.

The majority of the existing scholarship tend to interpret the Ottoman reforms in an overly descriptive or superficial manner, therefore neglecting the Ottoman decision-makers’ perceptions, plans, and broader goals as well as the subsequent effects (and repercussions) of those policies within the empire. The “Eastern Question” literature, which is mainly based on European sources, often ignores the Ottoman agency and obscures the rather complex nature of Ottoman policy-making by assessing it within a facile “modernist-reactionary” bipolarity for the period in question. With my holistic approach and utilization of unused archival material, I will contribute to the existing knowledge about Ottoman policy-making and political-military transformation during the era in question.

I argue in my thesis that the imperial center consciously, if frantically, responded to the internal and external challenges by tightening its grip around its subjects and making far-reaching changes in its governmentality. Aided by an expanding and diversifying military-administrative bureaucracy, Ottoman rulers managed to collect more taxes, create and expand a disciplined army, limit the power of provincial notables, standardize governing practices and pragmatically used their newly established European embassies to achieve their foreign goals. The social and economic costs of these policies were also immense, as I clearly underline in my study. Many common subjects and members of the higher classes expressed neither optimism nor pleasure about the top-down reforms and state policies. They were heavily taxed, suffered from rampant inflation, while tens of thousands of men were pressed into the new military formations to serve until they became disabled, deserted or died.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Grounded in archival research in Turkish historical repositories, this thesis examines the Ottoman ruling elite’s efforts to ensure the empire’s integrity and re-establish central authority by military-bureaucratic reform and internal negotiation in the second quarter of the 19th century. Going beyond the standard institutional histories and Eurocentric narratives of the Eastern Question, it explores how the Ottoman sultans and bureaucrats mobilized the empire’s political, military, and ideological resources to achieve their broader goals of reversing collapse and resisting European political-military challenge.


title: Mechanisms of host recognition and immune evasion of members of the Streptococcus anginosus/milleri group.

contributor:
Surette, Michael
Biochemistry and Biomedical Sciences

subject:
Streptococcus anginosus/milleri group
hTLR2
Streptococcus intermedius
intermedilysin
human cell responses
magellan6

abstract:
The Streptococcus Anginosus/Milleri Group (SMG) is made up of three closely related but distinct bacterial species: Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus. The SMG are recovered from about one-third of healthy, asymptomatic individuals. Despite this, the SMG cause more incidences of invasive streptococcal disease than Group A and Group B Streptococcus combined. Members of this group are somehow able to live a dual lifestyle. Little work has been conducted on the molecular pathogenicity of the SMG and host factors that contribute to host susceptibility to this group have been under-investigated. My research works towards discovering how the host recognizes the SMG as well as what enables the SMG to evade clearance by the immune system. I hypothesize that: 1) recognition of the SMG by toll-like receptor 2 (TLR2) plays a key role in triggering a cytokine response by the innate immune branch (which coordinates the immune response to the SMG), 2) the expression of cytolysins and extracellular polysaccharides by members of the SMG enables evasion of innate immune recognition and cytokine responses.
hTLR2 reporter and monocyte-like cell lines as well as human blood samples from healthy donors were used to investigate the host factors that contribute to SMG infection. Five clinical reference SMG strains and a transposon mutant library were used to probe the contributing bacterial factors. It was found that TLR2 activation plays an important role in the cytokine response to the SMG, but there is heterogeneity between strains in their ability to activate TLR2. It was also found that intermedilysin expression by S. intermedius strains enables evasion of recognition; however, different hosts display varying susceptibility to this cytolysin. This study reveals that investigation of both host and microbial factors is essential to build an understanding of the mechanisms of SMG transition from commensalism to pathogenicity.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The Streptococcus Miller/Anginosus Group (SMG) is a group of bacteria comprised of three species. Members of this group are recovered from roughly one-third of healthy individuals. However, the SMG are also found in samples collected from patients with invasive disease. It is not well understood why some human-SMG relationships are pathogenic and others are not. However, it is likely that the combination of both human and SMG factors determine the nature of the relationship formed between the two. In this study, the human and SMG factors that contribute to infection were investigated. The ways by which human cells recognize members of the SMG and defend themselves from damage was explored. Additionally, SMG factors that potentially contribute to infection were probed to discover their effect on human cells. By investigating both the bacterial and host factors that lead to infection, disease treatments and preventative strategies can be tailored to individual cases.


title: HUMANS SEEING HUMANS

title: AUTOMATIC, EMBODIED INFORMATION PROCESSING AND THE PRIMACY OF SOCIAL STIMULI IN HUMAN VISUAL ATTENTION

contributor:
Rutherford, M.D.
Psychology

subject:
visual attention
body perception
social cognition
embodied cognition

abstract: Three studies examined the impact of social stimuli on visual attention. Chapter two confirmed that, hands, feet, and bodies exhibited equivalent attentional pull in a dot probe detection, two-alternative forced choice paradigm. Chapter three utilized a Posner style covert attentional cueing paradigm to examine the impact of directed human action (throwing a ball) on spatial attention. We manipulated the effect of context by including social (humans) or non-social (trees) flanking images and probed the uniquely social nature of the processing in this task by including individuals with autism spectrum disorder (ASD), a group with known social deficits, as a comparison group. We also manipulated predictability using predictive and non-predictive cue blocks between subjects. Participants with and without ASD demonstrated similar cueing effects when cues were predictive. ASD participants showed no cueing advantage when cues were non-predictive while neurotypical participants experienced cueing only in social contexts when cues were non-predictive – consistent with automatic social processing. Intelligence as measured by the FSIQ from the WAIS 4 was also analyzed. Unexpectedly, higher IQ resulted in slower RTs with the ASD group. We examined this relationship further by examining severity of diagnosis measured by ADOS-G and FSIQ in participants with ASD. In a final study we looked at the relationship between RT and eye movements in visual search for social stimuli like faces and bodies. Consistent with previous results, faces resulted in faster RTs when they were the targets. They also elicited more first fixations and shorter fixation durations. Faces were not, however, more distracting when they appeared in irrelevant singleton frames. Unexpectedly, the bodies images used in this experiment did not result in attentional capture. Possible reasons for this are discussed.

abstract: Dissertation

abstract: Doctor of Psychology (PsyD)

abstract: As humans, other humans are among the most important things we visually perceive. They are sources of threat, alliance, uncertainty, and love. Because we cannot attend to all of the things we see at once, evolution has prepared us with mental traits that favour rapid processing of complex social scenes. Across three studies, we examine how other humans affect our attention. In the first study we confirm that human bodies and their parts (like feet or hands) are equally capable of drawing our attention. Our second study examines the ability of dynamic human poses to direct our attention in the direction of the depicted action. We note that an implied social interaction leads to better performance among typically developing individuals, but leads to deficits in individuals with autism spectrum disorder, a condition characterized by social delays and impairments. Finally, we look at how important social images, like human faces or bodies, unconsciously attract and influence our eyes movements when searching among distracting images.


title: Comparison of Sliding-Mode Control and Model-Predictive Control  Algorithms for Pneumatic Actuators

contributor:
Bone, Gary M.
Mechanical Engineering

abstract:
Pneumatic actuators are low-cost, clean, safe and provide a high power to weight ratio. In this thesis, the modeling and position control of pneumatic actuators is presented. Sliding-mode control and model-predictive control algorithms are compared.
The actuator’s main components consist of a double acting pneumatic cylinder and four two-way on/off valves. A nonlinear system model was developed. Its parameters were estimated from experiments. A novel friction model was presented and shown to be superior to the classical friction model. The system model was validated by comparing simulation and experiment results.
Three novel nonlinear control algorithms are designed and compared with two existing state-of-the-art sliding-mode control (SMC) algorithms. Two of the novel algorithms are modified versions of the existing SMC algorithms. The third is a discrete-valued model predictive control (DVMPC) algorithm. The designs and performance of the five control algorithms were compared.
Simulations and experiments demonstrated that the two modified SMC algorithms reduced both the position tracking errors and the valve switching frequency. Reducing a valve’s switching frequency has the benefit of prolonging its life. In the experiments on a cylinder with high friction seals, the steady state errors reduced 42% to ±0.3 mm. The valve switching frequency was also reduced by 34%. The switching frequency was further reduced by 32%, without significantly affecting the tracking performance, by incorporating a 5 ms zero-order hold. The five algorithms were simulated and compared on a high friction cylinder and a low friction cylinder to demonstrate their generality. In the simulations, the position tracking performance with DVMPC was similar to the best SMC algorithm, and the valve switching frequency with DVMPC was 34% lower. The three novel controllers were shown to be robust to increased and decreased payload mass. The DVMPC calculation times demonstrated that future experimental implementation of DVMPC is possible.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: Actuators produce forces and motions in machines. Pneumatic actuators are low-cost, clean, safe and provide a high power to weight ratio. In this thesis, the modeling and position control of pneumatic actuators is presented. The actuator’s main components consist of a pneumatic cylinder and four electronic valves. The dynamics of the actuator components are mathematically modelled. A novel friction model is presented. Each valve is switched either on (to allow airflow) or off (to prevent airflow) every few milliseconds using a computer-based control system. Three novel nonlinear control algorithms are designed and compared with two existing state-of-the-art algorithms. Simulation and experiments demonstrate that the three proposed control algorithms reduced the position tracking errors and valve switching frequency (leading to longer valve life) when applied to a pneumatic cylinder with high friction seals. The designed controllers are also simulated and compared on a lower friction cylinder to demonstrate their generality.


title: OLFACTORY DYSFUNCTION IN THE MRL MOUSE MODEL OF CNS SLE

contributor:
Sakic, Boris
Science

abstract: Systemic lupus erythematosus (SLE) is a chronic autoimmune / inflammatory disease that is frequently accompanied by brain atrophy and neuropsychiatric (NP) manifestations.  CNS involvement ranges from focal abnormalities to diffuse disorders, and according to more recent clinical data, may also include olfactory dysfunction of unknown etiology.  Similar to CNS SLE, spontaneous development of lupus-like disease in MRL/lpr mice coincides with neurodegeneration in periventricular regions and behavioural impairments in paradigms dependent on olfactory function.  However, previous studies could not resolve whether exploration-dependant deficits reflect changes in emotional reactivity / exploratory drive, or altered olfactory capacity.  The latter possibility was also supported by evidence of disturbed projection of neuroblasts to the olfactory bulb.  The aim of this thesis was then to examine whether lupus-like autoimmunity alters olfactory function, thereby affecting performance in other behavioural tasks.  Indeed, behavioural testing in a battery of paradigms revealed that lupus-prone MRL/lpr males spend less time exploring unfamiliar conspecifics and demonstrate age-dependant changes in responsiveness to attractant and repellant scents.  Sustained treatment with the immunosuppressant cyclophosphamide abolished signs of autoimmunity and improved responsiveness to an attractant and a novel object, thus indirectly supporting a cause-effect relationship.  In order to probe for pathogenic autoimmune factors, we administered CSF from CNS SLE patients and purified autoantibodies into the brains of healthy mice.  Sustained infusion of autoimmune CSF induced olfactory dysfunction, excessive immobility in the forced swim test, enhanced perseveration in a learning task, and altered several home-cage behaviours.  Direct exposure to purified antibodies produced broad, but relatively mild, functional changes in olfactory function, spatial learning / memory, and home-cage behaviour.  These findings provide an initial step toward understanding the nature and immunopathogenic mechanisms underlying early neurofunctional deficits in human and murine forms of CNS lupus.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Examination of the effects of AMP-activated protein kinase activation in obese mice

contributor: Medical Sciences (Cell Biology and Metabolism)

subject:
AMPK
diabetes
obesity
ACC
insulin resistance
NAFLD
fatty liver
exercise
high-intensity interval training
HIIT
metformin
R419
hyperinsulinemic-euglycemic clamp
skeletal muscle

abstract: The obesity epidemic is an important global health concern. Obesity is associated with a number of diseases including type 2 diabetes, non-alcoholic fatty liver disease (NAFLD), cardiovascular disease, and some cancers. Insulin resistance, a precursor to type 2 diabetes, is defined as an unresponsiveness of metabolic tissues to insulin, leading to long-term hyperglycemia and hyperinsulinemia. The fatty acid-induced model of insulin resistance indicates that an accumulation of lipid intermediates interferes with insulin signal transduction leading to insulin resistance. It is, therefore, important to examine means by which these lipid intermediates can be reduced to alleviate interferences in insulin signaling in the treatment of insulin resistance and type 2 diabetes. Exercise and metformin are two common interventions in patients with type 2 diabetes and obesity. They both commonly activate AMP-activated protein kinase (AMPK). AMPK contributes to a number of metabolic processes including increased glucose and fatty acid oxidation. However, the effects of AMPK activation on insulin sensitivity are currently not fully understood. This compilation of studies examined the insulin sensitizing effects of AMPK activation via metformin, exercise, and novel AMPK activator R419 in obese mice. In Chapter 2 we show that metformin increases AMPK phosphorylation of acetyl-CoA carboxylase (ACC) 1 Ser79 and ACC2 Ser212, resulting in increased fatty acid oxidation, decreased lipid content and improvements in hepatic insulin sensitivity. In Chapter 3 we show that exercise-induced improvements in insulin sensitivity occur independent of AMPK phosphorylation of ACC phosphorylation sites and independent of lipid content in the liver. Finally, in Chapter 4 we show that R419 improves skeletal muscle insulin sensitivity independent of AMPK and lipid content but improves exercise capacity via a skeletal muscle AMPK-dependent pathway in obese mice. These findings suggest that future studies examining the effects of AMPK activation in obesity will aid in our understanding of the mechanisms of insulin resistance and introduce methods of prevention and treatment of obesity and type 2 diabetes.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: POLYPYRROLE AND COMPOSITE MATERIALS FOR ELECTROCHEMICAL CAPACITORS

contributor:
ZHITOMIRSKY, IGOR
Materials Science and Engineering

subject:
Polypyrrole
Carbon nanotubes
Dispersion
Electropolymerization
Chemical polymerization
Electrochemical capacitors

abstract:
In this research, different anionic dopants were investigated for the fabrication of polypyrrole (PPy) electrode materials for electrochemical capacitors (ECs). Anionic dopants from catechol, salicylic acid and chromotropic acid family allowed for the formation of adherent PPy thin film on stainless steels current collectors by electropolymerization. Comparison between galvanostatic and pulse electropolymerization of PPy thin films was made. Pulse electropolymerization was found to provide improved impregnation of Ni plaque current collectors and formation of nanostructured coating. The electrodes prepared by pulse electropolymerization showed higher porosity, lower electrical resistance, higher capacitance and improved cyclic stability.
In order to overcome the mass loading limitation for thin film PPy electrodes, chemical polymerization of PPy was investigated. The use of fine particles, prepared by the chemical polymerization method, allows impregnation of Ni foams and fabrication of porous electrodes with high materials loading. Moreover, improved capacitive performance and cyclic stability was obtained for PPy electrodes with high materials loading using new anionic dopants.
To further improve the cyclic stability of PPy electrodes, multiwalled carbon nanotubes (MWCNT) were used for the fabrication of PPy-MWCNT composite materials due to their high surface area and excellent conductivity. Different dispersants as well as dispersing methods were studied in order to obtain stable MWCNT suspensions. Among those dispersants, multifunctional anionic dopants were found to benefit the formation of MWCNT suspension as well as the polymerization of PPy. A conceptually new approach has been developed for the fabrication of PPy coated MWCNT based on the use of multifunctional anionic dopants.
The use of PPy coated MWCNT allowed excellent electrochemical performance for high active mass loadings, required for commercial EC applications. The electrodes and devices made of PPy coated MWCNT showed high capacitance, good capacitance retention at high charge-discharge rates and good cycling stability. The record high capacitance achieved at high charge-discharge rates is promising for the development of high power ECs.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: COMBINED EXERCISE AND COGNITIVE TRAINING ENHANCES HIPPOCAMPAL-DEPENDENT MEMORY

contributor:
Heisz, Jennifer J
Kinesiology

subject: exercise, cognitive training, memory, hippocampus

abstract: There is an established link between exercise, neurogenesis, and memory. Most of this research has been focused on rodent models, with little known about the effects of exercise on cognition in young adults. In rodents, exercise promotes hippocampal neurogenesis by enhancing cell proliferation in the dentate gyrus, while cognitive training promotes hippocampal neurogenesis by enhancing cell survival. Both physical exercise and cognitive training independently induce hippocampal neurogenesis in rodents, suggesting that these different forms of training may work through complimentary neurological pathways to benefit hippocampal memory in young adults. The present study examined the effects of six weeks of physical exercise and cognitive training on hippocampal-mediated memory processes in young adults to determine whether combined training yields enhanced memory benefits. Sixty-six sedentary young adults (32 females; age range 17-30 years) were randomly assigned to one of four groups: 1) Exercise training group (n=15), 2) Cognitive training group (n=16), 3) Combined exercise and cognitive training group (n=18), or 4) No-contact control group (n=17). Memory performance was assessed before and after the intervention on a putative hippocampal neurogenesis-dependent task, the Pattern Separation task. Growth factors that support neuron survival and function, brain-derived neurotrophic factor (BDNF) and insulin-like growth factor 1 (IGF-1) were measured in blood serum using enzyme-linked immunosorbent assays (ELISA). Based on the literature, the combination of exercise and cognitive training was expected to improve pattern separation performance more than the exercise or cognitive training alone, and display augmented effects for high responders to the exercise training. Additionally, if BDNF and IGF-1 were found to be involved in the mechanisms regulating the observed changes in memory, they too were expected to increase the most from the combined training and be dependent on individual changes in aerobic fitness. Critically, the combination of exercise and cognitive training led to the greatest increase in memory requiring pattern separation [t(16) = 2.91, p < 0.01] , indicating improved hippocampal-mediated memory function. BDNF and IGF-1 were not associated with this change in memory performance but were associated with the individual’s response to the exercise training, such that high responders to exercise had greater BDNF [F(1, 29) = 7.81, p < 0.01] and IGF-1 [F(1, 29) = 5.09, p < 0.05] than low responders to exercise. The results suggest that exercise and cognitive training may work through synergistic mechanisms to enhance hippocampal neurogenesis and support pattern separation processing. However, BDNF and IGF-1 may not be mediating this change in memory function.

abstract: Thesis

abstract: Master of Science (MSc)


title: Reid and Perceptual Acquaintance

contributor:
Sassen, Brigitte
Philosophy

subject: Perception; Representation; Acquaintance; Common Sense; Sensation; Idea Theory; Epistemology; History of Philosophy; Metaphysics

abstract:
In the recent literature, there is some debate over Reid’s theory of perception.
Commentators are divided on whether or not Reid’s theory is consistent with an
acquaintance model of perception. I will show that Reid’s views are not consistent with
an acquaintance model, but that he nevertheless had good reasons to subscribe to this
model. There is, therefore, an interesting tension in Reid’s theory of perception. I then
develop a modified Reidian acquaintance model of perception as a way of resolving these
tensions in light of an argument contained in Reid’s Philosophical Orations, and defuse
recent objections to the acquaintance interpretation in the process.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: In this dissertation I examine an ongoing debate in the contemporary literature on Thomas Reid over the nature of his account of perception.  I argue that one interpretation of Reid’s theory of perception that has been entertained fails, and that this does not, for various reasons, bode well for the viability of his account.  I argue that Reid had available a straightforward way to revise his theory in order to avoid this difficulty, and I explicate this simple revision.


title: Seismic Displacement Demands on Self-Centering Single-Degree-of-Freedom Systems

contributor:
Wiebe, Lydell
Civil Engineering

subject:
self-centering system
displacement
seismic
single-degree-of-freedom

abstract: M.A.Sc. Thesis

abstract: Most conventional seismic design intends for key structural members to yield in order to limit seismic forces, leading to structural damage after a major earthquake. To minimize this structural damage, self-centering systems are being developed. But how to estimate the peak seismic displacement of a self-centering system remains a problem for practical design. This thesis addresses this need by presenting a parametric study on the seismic displacement demands of single-degree-of-freedom (SDOF) systems with flag-shaped hysteresis considering 13,440,000 nonlinear time history analyses. Ground motion records that represent seismic hazards in active seismic regions with stiff soil and rock site conditions are used. The influences of the four independent parameters that define a flag-shaped hysteresis are presented in terms of median displacement ratios, facilitating the design-level estimation of nonlinear displacement demands on self-centering systems from the spectra displacements of elastic systems. The influence of initial period on self-centering systems is similar to its influence on traditional systems with elastoplastic hysteresis, but a much lower linear limit can be adopted for self-centering systems while achieving acceptable peak displacements. Supplemental energy dissipation suppresses the peak displacement but additional energy dissipation becomes less effective as more is added. The effect of nonlinear stiffness is small as long as it is positive and close to zero, but a negative nonlinear stiffness can lead to unstable response. Self-centering systems located on rock sites usually have smaller displacement demands than those on stiff soil sites. When the damping ratio is increased or decreased, the displacement ratios do not necessarily decrease or increase consistently. A tangent stiffness proportional damping model is considered, leading to a significant increase in displacement demands but similar overall trends. Based on the observations, regression analysis is used to develop a simplified equation that approximates the median inelastic displacement ratios of self-centering systems for design.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Modeling and implementing distributed computing with applications in Multisensor-Multitarget Tracking

contributor:
Kirubarajan, Thia
Electrical and Computer Engineering

abstract:
Big data is a term used to describe quantities of data that are too large to process using traditional means of data processing. The rise of such quantities of data amongst virtually every industry has lead to changes in data processing paradigms that favour distributed architectures over centralized processing. However great care must be taken when designing such processing architectures as slight overhead in computing or communication can nullify gains achieved from distributing computations.

In this paper we discuss the theoretical elements involved in designing distributed systems and develop a heuristic for the performance of such a system. Our heuristic helps define when a problem requires distribution and informs designers in choosing the right topology to meet the needs of the problem and hardware involved.

Finally we present results from our own distributed computing architecture applied to a prediction problem in radar image processing.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: An Experimental Investigation of  the Effect of Heater Surface Preparation Method on Pool Boiling of Nanofluids

contributor:
Hamed, M. S.
Mechanical Engineering

subject: nanofluids boiling

abstract:
An experimental investigation was carried out to study the effect of heater surface preparation  on pool boiling of nanofluids. The boiling surface was prepared using different methods: (1)  using a diamond turning machine, (2) a conventional lathe machine, and (3) polished using emery sandpaper. The average surface roughness of  the diamond turning machined surface was 6 nm and 470 nm for the surfaces prepared using the lathe and sandpaper. The boiling surfaces considered in this study are flat copper surfaces with a diameter of 25.4 mm. Al2O3-Water nanofluids prepared using nanoparticles with an initial size  of 10 nm and  concentration of 0.05%wt were used throughout the present study. In order to  improve  the nanofluids stability Sodium dodecylbenzenesulfonate (SDBS) was added to the base fluid (water) with a concentration of 0.1%wt. In order to understand the effect of the nanofluids and the surfactant separately and together, pool boiling experiments using distilled water only, nanofluids, distilled water plus the SDBS surfactant, and nanofluids mixed with SDBS (nanosuspensions) were carried out  on clean surfaces. The  nanofluids and nanosuspensions boiling experiments were followed by distilled water boiling experiments in order to assess the change of the surface characteristics due to any  nanoparticles deposition. The same set of boiling experiments was  carried out  on each of the three prepared surfaces.
        The experimental results indicated  that for the smooth and rough machined surfaces, the heat transfer coefficient was increased for the nanofluids and the nanosuspensions  with respect to distilled water. Distilled water boiling experiments on the unclean (used) surfaces showed that the heat transfer behavior is almost similar to the distilled water on the clean surface, which indicates that the deposition on the smooth  and rough machined surfaces was minimal and hence  the enhancement in the heat transfer was due to the change in the thermo-physical properties of the nanofluids  and not due to the change in the heater surface condition.
        A similar trend was observed in the case of the polished surface in which case nanofluids and nanosuspensions resulted in an enhancement in the rate of heat transfer. However, distilled water boiled on unclean surfaces showed that the boiling curve has shifted to the left compared with the curve of the distilled water on the clean surface. Boiling of distilled water on unclean surfaces showed that the boiling curve was enhanced, which can be attributed to the change in the surface condition and the change in the thermo-physical properties of nanofluids. Photographs of the boiling surfaces and surface measurements taken before and after the nanofluids and nanosuspensions experiments showed that the machined surfaces had less nanoparticles deposition than the sandpaper polished surface. These results indicate that the method of surface preparation has a significant effect on nanoparticles deposition and consequently on the pool boiling heat transfer in which the polished surface tends to have higher number of the active nucleation sites.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: SOUND WAVES EXCITATION BY FLOW IN A PIPE HOUSING A SHALLOW CAVITY

contributor:
Ziada, Samir
Mechanical Engineering

subject:
Cavity flow
Fluid-acoustic resonance

abstract:
This research introduces a new application of the three microphones method, which was originally developed to analyse standing waves, to measure the aeroacoustic power of a duct housing a shallow cavity coupled with a longitudinal acoustic mode. In addition, this work provides, for the first time, the spatial distribution of the aeroacoustic sound sources over the cavity region for this type of flow-sound-structure interaction pattern. Furthermore, this research includes a comprehensive study of the effect of cavity geometrical parameters on the characteristics of the cavity aeroacoustic source.
An experimental investigation of the aeroacoustic source of an axisymetric cavity in a pipeline is presented. This aeroacoustic source is generated due to the interaction of the cavity shear layer oscillation with the resonant acoustic field in the pipe. The source is determined under high Reynolds number, fully developed turbulent pipe flow. The experimental technique (Sound Wave Method, SWM) employs six microphones distributed upstream and downstream of the cavity to evaluate the fluctuating pressure difference generated by the oscillating cavity shear layer in the presence of externally imposed sound waves. The results of the dimensionless aeroacoustic sources are in good agreement with the concepts of free shear layer instability and the fluid resonant oscillation behavior.
A validation study is performed in order to validate the measurement technique and the measured source term from the SWM. The validation methodology consisted of comparing the self-excited resonance response obtained from self-excitation measurements with that estimated from an acoustic model supplemented with the measured source term using the SWM. The comparison depicts a very good agreement for the resonance frequency, lock-in ranges, and the resonance amplitude.
Extensive PIV flow measurements are performed to clarify the non-linear behavior of the aeroacoustic source at high levels of the acoustic particle velocity, and to understand the dependence of the flow-sound interaction patterns on the main system parameters such as the Strouhal number and excitation level. The results of a finite element analysis of the resonant sound field are combined with those of the PIV flow measurements into Howe’s aeroacoustic integrand to compute the spatial and temporal distributions of the aeroacoustic sources. The results are also compared with the measured aeroacoustic source strength obtained by means of the SWM. This comparison highlights the superior efficiency of the SWM technique. Identification of the aeroacoustic source distributions as function of the acoustic excitation level showed that the non-linear behaviour of the source strength, which occurs at moderate sound levels, is caused by a gradual transition in the vorticity field oscillation pattern; from a distributed vorticity cloud over the whole cavity length at small excitation amplitudes to a pattern involving rapid formation of (discrete) vortices at the leading edge which becomes dominant at large excitation levels.
The spatial distribution of the acoustic power over the cavity length at resonance condition shows sources of sound generation at the first and last thirds of the cavity mouth and an absorption sink in the middle third. This distribution is different from that observed for deep cavities and trapped modes of shallow cavities. Due to these differences in the aeroacoustic source distributions, the effects of cavity geometrical parameters for the present shallow cavity are not necessarily similar to those reported in the literature for deep cavities and trapped mode resonance cases.
A comprehensive study of the effect of cavity geometrical parameters (including rounding-off the cavity edges) on the aeroacoustic sound sources is also included. Nine cavity sizes are studied in three different groups of length to depth ratios (L/H) with three different cavity volumes for each group of L/H. The aeroacoustic source strength and the Strouhal number corresponding to its maximum value are found to increase in a systematic manner as the cavity volume is increased for the same L/H ratio. These results indicate that the aeroacoustic sources of shallow cavities are affected not only by the ratio L/H, but also by the cavity volume.
The effect of cavity edge curvatures on the resonance response is experimentally investigated by testing different sizes of curvatures at different locations (upstream, downstream or both edges). The results show that rounding-off the cavity edges causes a reduction in the vertical component of the acoustic particle velocity but also an increase in the cavity length. These two consequences have opposite effects on acoustic power generation and therefore, rounding-off the edges has no significant effect on the resonance amplitude in the present case, except for relatively large radius.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Building Great Lakes Resiliency to Eutrophication: Lessons to inform adaptive governance of the nearshore areas of the Laurentian Great Lakes.

contributor:
Krantzberg, Gail
Engineering

subject: Great Lakes, eutrophication, nutrient enrichment, resiliency, adaptive governance, adaptive capacity, nearshore areas

abstract:
Annex 2 of the Great Lakes Water Quality Protocol calls for the collaborative development of a ‘nearshore framework’, but does not provide guidance with respect to nearshore governance. This thesis bridges this gap with a series of studies on the determinants for adaptive governance that will inform implementation of the Great Lakes Water Quality Protocol 2012.

The principal focus of this work is on eutrophication, which is essentially a nearshore issue.  The methodology includes a comprehensive literature review and 35 key informant interviews using a standardized questionnaire. The results assess Great Lakes governance, examine the strengths of the Great Lakes Water Quality Agreement Protocol 2012 and evaluate the effectiveness of the International Joint Commission. A major product of the research is the development of a framework for assessing adaptive capacity based on six determinants: public participation, science, networks, leadership, flexibility and resources. The framework is validated in the case study of eutrophication in Lake Erie and used to identify gaps in adaptive capacity for current eutrophication governance of Lake Erie.

The framework was then tested on two additional case studies, the Chesapeake Bay and the Baltic Sea Region. These systems are both eutrophic and are similar in many other ways to the Great Lakes. This allowed exploration of issues of scale, from local (Chesapeake Bay) to binational (the Great lakes) to transnational (the Baltic Sea).

The most important finding of this work is that the key barrier for building adaptive capacity for eutrophication governance in the Great Lakes is the lack of adequate leadership and resources. A key recommendation is therefore that the IJC be strengthened in its role to function as a collaborative leader to foster adaptive capacity. The findings from this research can inform the implementation of the Great Lakes Water Quality Protocol 2012.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A New Approach to Radiative Transfer in Galaxies

contributor:
Wadsley, James
Couchman, Hugh
Physics and Astronomy

subject:
methods:numerical
methods:radiation
simulations: galaxy

abstract:
In this thesis, we present a novel algorithm for computing the radiation field in
astrophysical simulations. The algorithm is tree-based, similar to many gravity
solvers, and allows computation of radiative transfer in O(Nsink logNsource) in
cases without absorption, and O(Nsink logNsource logN) time with absorption.
The algorithm scales well with the number of processors due to its tree-based
nature, and is highly tunable in accuracy and speed. It is also only weakly
dependent on both the energy band and the number of energy bands used.
We provide a suite of tests of the code showing its ability to create accurate
fluxes, ionization fronts, hydrodynamics coupling, and shadowing.
We apply the algorithm in a set of simulations on an isolated spiral
galaxy from the AGORA project. The algorithm is used to calculate FUV
fields within the galaxy, which self-consistently sets the dominant photoelectric
heating in the gas. This has never before been performed in galaxy simulations.
We find, in agreement with Ostriker et al. [2010], that FUV can be a very
important regulation mechanism for star formation in a galaxy. Depending
on the assumed opacity, FUV can decrease the average star formation rate
(SFR) anywhere from 15% to a factor of twenty. We compare this regulation
mechanism to a highly effective model of supernovae (SNe) feedback, which
reduces the SFR by a factor of twenty as well. However, SNe feedback destroys
most of the gas structure in the process, whereas FUV has minimal impact on
the gas structure.
In the simulations with FUV radiation, we are also able to create a two
phase medium that is a function of the mean FUV intensity the gas receives.
Finally, we find that simulations with FUV agree well with observations of
nearby spirals on the Kennicutt-Schmidt relation, at least at gas surface densities
of 0.2 - 30 M⊙. At surface densities higher than 30 M⊙, we find that
FUV is not an effective regulator which is consistent with arguments that SNe
or other feedback mechanisms should become the primary regulator.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Investigation and Characterization of Rare-earth Pnictide Suboxides for Thermoelectric Applications

contributor:
Mozharivskyj, Yurij
Chemistry and Chemical Biology

subject: Rare-earth pnictide suboxide

abstract:
Several rare-earth pnictide suboxides were investigated for their structures, chemistry, and physical properties. The goal of this research was to develop a highly stable material that could combine the thermally insulating properties of a rare-earth oxide framework with the electrically conductive properties of a rare-earth pnictide framework. These materials were synthesized by solid state reactions at high temperatures, producing highly pure products for measurement. All phases were subjected to several different forms of analysis, including X-ray powder and single crystal diffraction, energy dispersive X-ray spectroscopy (EDS), electron microprobe analysis (EPMA), magnetization, and hall resistivity measurements. Sufficiently pure bulk samples were then measured for thermoelectric properties in terms of electrical resistivity, Seebeck coefficient, and thermal conductivity, where applicable. The roles of structure and chemistry for each phase were then discussed with respect to the obtained physical properties and calculated electronic structures.
Seven distinct classes of rare-earth pnictide suboxides were investigated in this dissertation: the tetragonal (REIREII)3SbO3 phases (space group C2/m), the CaRE3SbO4 phases (space group I4/m), the Ca2RE8Sb3O10 phases (space group C2/m), the Gd3BiO3 phase and Gd8Bi3O8 phases (space groups C2/m), and the Ca2RE7Sb5O5 phase and Ca2RE7Bi5O5 phases (space groups P4/n). All of these phases share many common structural features, and can be related by different RE4O tetrahedral building block stacking sequences and locations of the pnictide atoms.
Structurally speaking, the simplest possible arrangement of the RE-O and RE-Pn frameworks we investigated are found in the CaRE3SbO4 phase. This phase contains the smallest unit cell of all known rare-earth pnictide suboxides with only a two unit RE4O tetrahedral building block and ordered antimony atoms. Extended heat treatments gradually convert this phase into the corresponding Ca2RE8Sb3O10 phase, with a significantly more complicated arrangement of RE4O building blocks. By controlling the loading composition and reaction conditions, the CaRE3SbO4 phase can be prepared as a kinetic product, while the Ca2RE8Sb3O10 phase forms as the thermodynamic product. Likewise, the tetragonal (REIREII)3SbO3 phases can also be prepared through high temperature reactions. This phase contains a unique three RE4O unit (RE8O3) building block in its structure, which creates two rare-earth sites with a large difference in site volume. Thus, this phase can only be prepared when two rare-earth atoms of sufficiently different size are present.
Despite similar structures, the physical properties of the studied rare-earth pnictide suboxide phases can display quite different behavior. For the CaRE3SbO4, Ca2RE7Sb5O5, Ca2RE7Bi5O5, and tetragonal (REIREII)3SbO3 phases, the electrical resistivity remains fairly constant throughout the series, which can be traced to their highly ordered structures, as well as the physical and chemical similarities between rare-earths. Conversely, the more structurally disordered Ca2RE8Sb3O10 and Gd8Bi3O8 phases behave as semiconductors despite the fact they are not charge balanced. This anomalous behavior arises from the disorder of Sb and Bi atoms, which are responsible for electrical conduction in the phase. Interestingly, the level of disorder and thus, the magnitude of the electrical resistivity, can be greatly influenced by the rare-earth atom that is present, despite maintaining similar structures and charge carrier concentrations. Smaller rare earth atoms introduce a larger chemical pressure on the disordered antimony/bismuth atoms which lowers the range of Anderson localized states, pushing the system closer to metallic-type conduction.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Multi-year water balance dynamics of a newly constructed wetland, Fort McMurray, AB

contributor:
Carey, Sean
Earth and Environmental Sciences

subject:
hydrology
water balance
reclamation
oil sands
peatland
evapotranspiration
energy balance
wetland

abstract: Oil sands mining in Alberta completely transforms the natural boreal landscape of upland forests, wetlands and lakes into open pits, tailings and overburden piles. By law, industry is required to return the landscape to its pre-disturbance land capability. While previous reclamation efforts have mainly focused on upland forest ecosystems, rebuilding wetland systems on soft tailings has only recently become a research focus. The dry, sub-humid climate and high salinity levels of underlying mining material complicate reconstruction of wetlands within this region. In 2012, Syncrude Canada Ltd. completed construction of the Sandhill Fen Watershed (SFW), a 52-ha upland-wetland system to evaluate wetland reclamation strategies. SFW includes an active pumping system, upland hummocks, a fen wetland and underdrains. This study examined the watershed-scale water balance in the first two years after commissioning (2013 and 2014). The first paper presents a semi-distributed water balance approach examining the fluxes and stores of different landscape units. Artificial pumping controlled the water balance in 2013, with approximately double the annual precipitation pumped in and out from May-Oct 2013, causing large water table fluctuations. In 2014, pump management was more passive, and water balance controlled by vertical fluxes. In the second paper, growing season ET rates and controls were assessed using data from three eddy covariance towers in the uplands and lowlands. Average ET rates between uplands and lowlands were similar, with average rates of 2.41 – 2.52 mm d-1. ET was radiatively controlled at all sites. Energy partitioning and ET rates are similar to natural boreal peatlands within the area, however upland areas are expected to increase in ET rates as LAI increases and vegetation matures. This study provides critical quantitative data on the early years of a highly managed watershed. Long-term monitoring is necessary, as water balance dynamics will evolve with vegetation development and climate cycles.

abstract: Thesis

abstract: Master of Science (MSc)


title: New Workers’ Experiences in Child Welfare

contributor:
Dumbrill, Gary
Sammon, Sheila
Social Work

subject:
New Workers
Child Welfare

abstract:
ABSTRACT
	How as a new worker could I have become better prepared by my education for child welfare work? What have other new workers experienced through their education that helped prepare them or hindered them?  Lastly what are some creative ideas to better prepare new workers, specifically social workers, for the reality of working in child protection? These questions formed the focus of this study, which includes a literature review on new worker readiness and findings from qualitative interviews with new workers which utilizes an insider perspective towards data analysis. The participants in this research had varying experiences as new workers, however similar themes emerged. New workers struggled with power and experienced feelings of hopelessness and helplessness. New workers had difficulty transferring theoretical knowledge from their education into practice and did not feel prepared for the reality of child welfare work. Participants also described how they internalized conflict and the stress of the job. They suggested ways of coping including supportive supervision and a collaborative team environment. Increasing new workers’ confidence was also seen as key to prepare new workers for a child protection position. This research was conducted through a partnership with my fellow MSW researcher Julie Huynh-Lauesen, who coauthored the literature review and conducted a similar, yet separate research study with child welfare managers. Both studies were then compared and contrasted for discussion and future  purposes.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: In situ gelling hydrogel for topical and mucosal applications

contributor:
Hoare, Todd
Biomedical Engineering

abstract:
Hydrogel networks have attracted considerable research interest due to their potential in multiple biomedical applications, including drug delivery, wound healing, tissue engineering, and biomedical equipment coatings. In particular, multi-functional hydrogels that are injectable, non-cytotoxic, anti-bacterial, and bioadhesive offer potential applications in wound management, surgical barrier materials, and mucosal or skin-based drug delivery.  In this thesis, an in situ injectable hydrogel network based on chitosan and poly(oligoethylene glycol methacrylate (POEGMA) was prepared using covalent aldehyde-hydrazide chemistry to form a stable hydrazone bond that is biodegradable, biocompatible, and adaptable to form networks with varying mechanical properties. Chitosan, a cationic polymer, has inherent adhesive and antibacterial properties, while POEGMA is innately protein-repellent and non cytotoxic. Therefore, by combining these materials, a non-cytotoxic and degradable hydrogel with both adhesive and antibacterial properties can be produced, with potential applications in drug delivery and wound healing.
The focus of this thesis is to functionalize chitosan to possess hydrazide groups without losing its inherent adhesive and antibacterial characteristics. This was be confirmed through titration and FT-IR to confirm and quantify the degree hydrazide functionalization followed by typical hydrogel characterization such as gelation time, degradation kinetics at different pH, transparency, and mechanics to ensure the required criteria for potential use in vaginal and skin applications are all met. The adhesive properties of the hydrogel with biological tissue (porcine skin) were assessed using peel and tack testing strategies, while mucoadhesion potential was screened using tack tests relative to a model mucosal membrane. Antibacterial properties of the functionalized chitosan polymer and chitosan-POEGMA hydrogel were characterized using minimum inhibitory concentration measurements, zone of inhibition assays, macro broth dilution, and LIVE/DEAD bacterial assay using E.coli as the bacterial model. Different chitosan weight percentage incorporations in the hydrogel matrix were investigated and compared, both internally as well as with a cationic POEGMA-POEGMA hydrogel to identify the role of chitosan in controlling the gel properties.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Design and Characterization of a Nanoscale Carbide-Free Bainite Alloy

contributor:
Fazeli, Fateh
Botton, Gianluigi
Lo, Jason
Materials Science and Engineering

subject:
Super bainite
Bainite kinetics
Ausforming
Dilatometric study
Electron Backscattered Diffraction

abstract:
High carbon bainitic steel plates could surpass quench and tempered martensitic counterparts for fabrication of ammunition- and blast-resistant armours. Mechanical properties, microstructure and reaction kinetics of a commercially available carbide-free nanoscale bainite alloy were characterized. Based on the initial characterization and a comprehensive review of the literature a new alloy with lower carbon, higher silicon and cobalt additions was designed and processed into hot-rolled plates (10x10mm and 300x300mm) using CanmetMATERIALS pilot-scale facilities. The heat treated plates achieved strength above 2 GPa with elongation of 14%. Thorough analysis with electron backscattered diffraction revealed that the microstructure consisted of bainitic ferrite laths, islands of retained austenite, areas of mixed martensite-austenite (MA). Transmission electron microscopy confirmed the fine scale of bainitic ferrite and the presence of thin films of retained austenite encompassing bainite laths.
	Dilatometric study of the new alloy revealed that forming bainite at higher transformation temperatures, 275°C versus 250°C and 225°C, led to faster overall reaction kinetics and higher final fractions of bainite within 18 hours of isothermal holding. Although it is expected that the fraction of bainite increases at lower temperatures, substantial prolonged holding time is required for completion of the reaction. Microstructural features and particularly bainite lath thickness depended on bainite formation temperature. Ausforming, deformation of austenite at 600°C for 25-45% strain prior to decomposition to bainite, however led to a decrease in reaction rate and final fraction of bainite.
	Tensile testing of austempered specimens showed that higher transformation temperature yielded a stronger microstructure, which was attributed to the formation of thinner bainitic ferrite laths. Higher transformation temperatures led to an increase in ductility. Tensile testing of the ausformed specimens showed a reduction in both strength and ductility. A negative correlation was seen between the amount of MA areas in the microstructure and total elongation.

abstract: Thesis

abstract: Master of Science in Materials Science and Engineering (MSMSE)

abstract: This project has adopted the science of bainite transformation to develop a suitable alloy and processing method for the fabrication of very strong armour plates at a lower cost compared to commercially available grades. The pilot-scale casting and processing facility at CanmetMATERIALS centre was used to produce full sized, 1ft (304.8mm) by 1ft (304.5mm), prototype armour plates. The plates were subsequently characterized using a variety of techniques to determine interplay between processing parameters, microstructure and the ensuing final performance. The optimized alloy, tailored processing parameters, and characterization information constitute the contribution of the present work to the current state of research.


title: SEX AND GENDER DIFFERENCES IN THE MANAGEMENT AND TREATMENT OF OPIOID ADDICTION

contributor:
Samaan, Zainab
Neuroscience

subject:
Addiction
Opioids
Methadone
Sex Differences

abstract:
Background and Objectives: Opioid addiction is a major contributor to the global burden of disease and carries a significant risk of morbidity and mortality. Individuals with opioid addiction are subject to numerous adverse consequences including infectious diseases, medical complications, psychiatric disorders, and social disintegration. Women especially experience a heightened vulnerability to the adverse medical and social consequences of opioid addiction as a result of biological sex characteristics and socially-defined gender roles, which increases their risk for poor treatment outcomes. The general objective of this thesis if to investigate sex and gender differences in the management and treatment of opioid addiction with a focus on hormonal influences, genetic variation, and sociobehavioral characteristics including substance use behavior, health status, and social functioning.
Methods: Using various methodologies, we compared the biological and social characteristics of men and women with opioid addiction in the context of methadone treatment. We assessed sex and gender differences in methadone treatment outcomes using a systematic review of the literature and a meta-analysis, which was developed based on published protocol. Next, we used data from the multi-centre GENOA cross-sectional study including 250 patients with opioid addiction recruited from Ontario methadone clinics to measure testosterone levels among men and women compared to non-opioid using controls; total serum testosterone was assayed using ELISA and RIA techniques. Following this study, we conducted a systematic review and meta-analysis to test the effect of opioid use on testosterone levels, performing subgroup analyses by sex and type of opioid used. Using the previous GENOA sample, we then completed genotype analysis on variants of BDNF and DRD2 genes to test the genetic effect on continued opioid use, measured through urine drug screening. Finally, we recruited an additional 503 participants meeting criteria for opioid use disorder who were receiving treatment with methadone, from which we obtained information on drug use patterns and addiction severity using the Maudsley Addiction Profile (MAP) tool to evaluate sex and gender differences.
Results: In our initial systematic review, we found 20 studies collectively showing that women were less likely than men to report alcohol use, employment, or legal involvement, but were more likely to misuse amphetamines. Using the GENOA dataset of methadone patients, we found a significant reduction in testosterone level among men but not women, which was associated with methadone dose. We also determined that testosterone did not fluctuate significantly between menstrual cycle phases. In line with these findings, our systematic review showed a significant suppression in mean testosterone level among men that use opioids compared to controls, but not in women. Our results also showed that methadone did not affect testosterone differently than other opioids. Among GENOA participants, BDNF rs6265 and DRD2 rs1799978 genetic variants were not significantly associated with continued opioid use while in methadone maintenance treatment. Our final study identified sex and gender differences in substance use, health status, and social functioning. Women were younger, had children, were current smokers, had higher rates of benzodiazepine use, more frequent physical and psychological health problems, family history of psychiatric disorders, more partner conflict, and began regular use of opioids through a physician prescription. In comparison, men were more likely to be employed and to report cannabis and amphetamine use.
Conclusions: This thesis has demonstrated that men and women are differentially affected by opioid addiction and experience sex- and gender-specific challenges throughout the course of methadone treatment that are likely to impact treatment outcomes. The identification of clinically-relevant sex and gender differences is important to our understanding of the addiction profile, and can therefore be used to promote strategies for effective treatment and management of opioid addiction among men and women incorporating both biological and social perspectives.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: CHARACTERIZING TRANSCRIPTIONAL AND POST-TRANSCRIPTIONAL REGULATORS IN STREPTOMYCES BACTERIA

contributor:
Elliot, Marie
Biology

abstract:
The final stage of transcription, termed termination, is required for proper gene expression in bacteria. However, the mechanism of transcription termination is poorly understood in the multicellular Streptomyces bacteria. Motivated by the lack of well characterized terminators, we systematically searched for intrinsic termination signals in three divergent Streptomyces species. Using a novel computational approach we identified hundreds of biologically relevant terminators in each species. Many of these terminators were found downstream of annotated genes and aligned nicely with intrinsic terminators identified by other prediction algorithms. Further in silico analyses indicated that the streptomycetes prefer to terminate transcription at non-canonical structures characterized by a long hairpin lacking a trailing U-rich tract. We prioritized three structurally diverse intrinsic terminators for in vivo analysis. Due to difficulties optimizing a fluorescent reporter assay, we have not yet been unable to measure termination efficiency in vivo. Current work is focused on developing a new reporter system that can be used to characterize putative Streptomyces terminators.
In this work, we have also investigated small RNA (sRNA)-mediated regulation in Streptomyces. These bacteria encode hundreds of sRNAs, although very few have been characterized to date. As a result, we designed an affinity purification system that can be used to identify sRNA interaction partners (e.g. proteins and RNAs). Initially, we tried to implement a system using a highly structured streptavidin aptamer; however, sRNAs tagged with this aptamer were not stably expressed in vivo and did not appear to re-fold effectively in vitro. More recently, we have tagged several sRNAs with a different aptamer which binds the MS2 phage coat protein. Future experiments will focus on testing the functionality of these new RNA fusions in vivo.

abstract: Thesis

abstract: Master of Science (MSc)


title: Social Cognition Performance in Individuals with Post Traumatic Stress Disorder

contributor:
McKinnon, Margaret
Neuroscience

subject:
Social Cognition
PTSD
Theory of Mind
Emotion Comprehension
Morality

abstract: Social cognition, the ability to understand the thoughts and feelings of oneself and others, is central to optimal navigation of the social world. Accumulating evidence suggests disruptions in social cognition may underlie the interpersonal dysfunction commonly experienced by individuals with several psychiatric disorders such as schizophrenia, bipolar disorder, major depressive disorder, and post-traumatic stress disorder (PTSD). Exposure to psychological trauma can have lasting and debilitating effects on an individual, with a subset developing PTSD as a result, marked by symptoms of re-experiencing, mood disturbances, arousal changes, emotional dysregulation, and in turn, poor interpersonal and general functioning. Here, we investigated the effects of psychological trauma exposure on sociocognitive performance across the domains of emotion comprehension in prosody, theory of mind (ToM), and moral reasoning. This thesis contributes unique findings to the PTSD literature by demonstrating that individuals diagnosed with PTSD stemming from chronic childhood trauma experience alterations in emotional comprehension of prosody, ToM performance, and moral reasoning. Furthermore, we have integrated and summarized literature on the interaction of morality, moral transgressions, the experience of shame and guilt, and the emergence of associated adverse mental health outcomes experienced in a military context.  In summary, we have demonstrated that sociocognitive skills are disrupted in individuals exposed chronic psychological trauma and that moral emotions such as guilt and shame play an important role in the emergence of PTSD and its resistance to treatment. These disruptions may represent a central therapeutic focus in the pursuit to ameliorate the interpersonal difficulties experienced in trauma and stress-related disorders.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Body mass index and cardiovascular clinical outcomes after acute coronary syndromes

contributor:
Schwalm, Jon-David
Health Research Methodology

subject: acute coronary syndromes, mortality, body mass index, obesity, overweight

abstract:
Obesity, assessed by body mass index (BMI), is considered a major public health problem worldwide.  Studies in people without CVD, have shown that BMI between 22.5 to 24.9 kg/m2 is associated with the lowest risk of death in healthy non-smoker populations. However, studies in patients with acute coronary syndrome (ACS) have shown that overweight and obese patients have better survival than those in the normal BMI range. This phenomenon has been called the “obesity paradox”.
This thesis has two main components: a systematic review with meta-analysis of the current literature of BMI and ACS, and an individual patient data meta-analysis from 8 randomized trials whose data base was accessible at the PHRI involving ACS patients. The study-level systematic review (35 studies) and meta-analysis (19 studies) demonstrates  that there is a statistically significant adjusted 20% risk lower  mortality  among overweight and obese participants considered normal weight. Nevertheless, there was moderate to high heterogeneity of pooled estimates that could not be explained in subgroup analyses. Also, the systematic review detected major limitations in the current literature, including missing BMI and covariates data, lost to follow-up, enough number of events in high BMI categories, warranting more research in the area.
The second component, the individual patient data meta-analysis (n = 81,553), confirmed a 20% lower mortality risk in the overweight and type I obesity categories, compared to the normal the BMI range. This lower risk was robust and remained consistent within several sensitivity analyses. Analysis of secondary outcomes suggests that a reduced risk of bleeding, and probably a reduced risk of ischemia and heart failure related deaths, are the responsible mechanisms. Given the limitations of observational research, prospective randomized interventional trials are required to clarify the optimal range of BMI in those with ACS.

abstract: Thesis

abstract: Master of Health Sciences (MSc)


title: Key-Frame Based Video Super-Resolution for Hybrid Cameras

contributor:
Shirani, Shahram
Electrical and Computer Engineering

subject:
Video Super-resolution
Hybrid Cameras
High Frequency Restoration
EngineX Simulator
Key-frame

abstract: This work focuses on the high frequency restoration of video sequences captured by a hybrid camera, using key-frames as high frequency samples. The proposed method outlines a hierarchy to the super-resolution process, and is aimed at maximizing both speed and performance. Additionally, an advanced image processing simulator (EngineX) was developed to fine tune the algorithm.

abstract:
Super-resolution algorithms are designed to enhance the detail level of a
particular image or video sequence. However, it is very difficult to achieve in
practice due to the problem being ill-posed, and often requires regularization
based on assumptions about texture or edges. The process can be aided using
high-resolution key-frames such as those generated from a hybrid camera. A
hybrid camera is capable of capturing footage in multiple spatial and temporal
resolutions. The typical output consists of a high resolution stream captured at
low frame rate, and a low resolution stream captured at a high frame rate.
Key-frame based super-resolution algorithms exploit the spatial and temporal
correlation between the high resolution and low resolution streams to
reconstruct a high resolution and high frame rate output stream.

The proposed algorithm outlines a hierarchy to the super-resolution process,
combining several different classical and novel methods. A residue formulation
decides which pixels are required to be further reconstructed if a particular
hierarchy stage fails to provide the expected results when compared to the low
resolution prior. The hierarchy includes the optical flow based estimation which
warps high frequency information from adjacent key-frames to the current frame.
Specialized candidate pixel selection reduces the total number of pixels
considered in the NLM stage. Occlusion is handled by a final fallback stage in
the hierarchy. Additionally, the running time for a CIF sequence of 30 frames
has been significantly reduced to within 3 minutes by identifying which pixels
require reconstruction with a particular method.

A custom simulation environment implements the proposed method as well as many
common image processing algorithms. EngineX provides a graphical interface where
video sequences and image processing methods can be manipulated and combined.
The framework allows for advanced features such as multithreading, parameter
sweeping, and block level abstraction which aided the development of the
proposed super-resolution algorithm. Both speed and performance were fine tuned
using the simulator which is the key to its improved quality over other traditional
super-resolution schemes.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Investigating the Association between Exposure to Secondhand Smoke in Utero and Developmental Coordination Disorder

title: Smoke Exposure and Developmental Coordination Disorder

contributor: Clinical Health Sciences (Health Research Methodology)

subject:
Developmental Coordination Disorder
DCD
Secondhand Smoke Exposure
SHS
ADHD

abstract:
Affecting approximately 5-6% of the primary school population, developmental coordination disorder (DCD) is a condition characterized by poor motor proficiency that interferes with a child’s activities of daily living. The cause of DCD is not yet understood; however, it is known that children with DCD are more likely to have other co-occurring developmental disorders such as attention-deficit hyperactivity disorder (ADHD). While there is a growing body of evidence linking ADHD to smoke exposure in utero, there is limited research investigating a similar link between smoke exposure in utero and DCD. The purpose of this study was to examine the effect of SHS exposure in utero in children with DCD and a group of typically developing (TD) children.
Methods – A case-control study was conducted to compare children with DCD to TD children on their exposure to SHS in utero and other demographic variables. At baseline, participants included 63 DCD children and 63 healthy controls. All children were assessed for motor proficiency, intelligence, and ADHD. Mother’s SHS exposure during pregnancy and other demographic variables were obtained from a parent completed survey.
Results – Multinomial logistic regression analyses revealed that children exposed to SHS in utero were significantly more likely to be at high risk for DCD than children who were not exposed to SHS in utero, even after adjusting for associated demographic variables. Furthermore, children exposed to SHS in utero were significantly more likely to be at moderate-high risk for DCD, whether or not ADHD was co-occurring.
Conclusion – Results from this study suggest that exposure to SHS during pregnancy has negative effects on fetal development and appears to be a contributor for DCD. Further study is needed to examine the specific mechanisms linking SHS exposure in utero to motor coordination problems in children.

abstract: Thesis

abstract: Master of Science (MSc)


title: Activity and Aging in Adult Males: Investigation of Entheses and Cortical Bone from the Site of Lisieux-Michelet in Northern France

contributor:
Brickley, Megan
Anthropology

subject:
osteology
entheses
male health
cortical bone

abstract:
Cortical thickness and entheseal robusticity were used to measure the effects of activity and age in a group of 77 adult males from the site of Lisieux-Michelet in northern France. There was no known age at death for this population; age was determined using a series of osteological age estimation methods. Based on the currently available dates for this sample, the skeletal remains were primarily from the Late Roman Period (3rd-7th century AD).The adults were divided into three age categories based on these estimation results.
Trends in cortical and entheseal development were measured within and between age categories. Results showed that entheses increased with age while cortical thickness decreased. However, low correlation between these two factors suggests that while entheseal robusticity responds to age, it is highly influenced by physical activity. Activity levels also affect cortical thickness which causes variation within age groups.
A comparison of the Lisieux-Michelet entheseal and cortical measurements to both modern and archaeological populations indicated that these males engaged in physically demanding occupations. The degree of activity experienced by these individuals decreased during the middle adult years likely due to a shift to less physically demanding occupations. However, cortical and entheseal data suggest that the old adults from Lisieux-Michelet were not particularly frail and continued to be active even after the decrease in activity during the middle years.

abstract: Thesis

abstract: Master of Arts (MA)