title: Hippocampal Neurogenesis In Amyotrophic Lateral Sclerosis Like Mice

contributor:
Tarnopolsky, Mark A.
Medical Sciences

subject: G93A SOD1 mice, G93A mice, Cu/Zn-SOD gene, amyotrophic lateral sclerosis (ALS), neurodegenerative disease, Hippocampal neurogenesis, subgranular zone, SGZ, dentate gyrus, DG, pathological, physiological processes, wild type, WT, SED, EX, treadmill exercise, EX, BrdU, mRNA

abstract: G93A SODI mice (G93A mice) are a transgenic model over-expressing a mutant human Cu/Zn-SOD gene, and are a model for amyotrophic lateral sclerosis (ALS), a predominantly motor neurodegenerative disease. Hippocampal neurogenesis in the subgranular zone (SGZ) of dentate gyms (DG) occurs throughout the life. It is regulated by many pathological and physiological processes. There is controversy with respect to the basal level of hippocampal neurogenesis and its response to exercise in neurodegenerative diseases and their mouse models. Little information regarding hippocampal neurogenesis is available in G93A mice. The present study was designed to study the impact of treadmill exercise and sex differences on hippocampal neurogenesis in this model. In addition, potential molecular mechanisms regulating hippocampal neurogenesis including growth factors (BDNF and IGFl) and oxidative stress (SOD2, catalase, 8-0Hdg, and 3-NT) were also addressed in the study. Bromodeoxyuridine (BrdU) was used to label newly generated cells. G93A and wild type (WT) mice were subjected to treadmill exercise (EX) or a sedentary (SEO) lifestyle. Immunohistochemistry was used to detect BrdU labeled newly proliferating cells, surviving cells, and their phenotype, as well as for determination of oxidative stress. BDNF and IGFl mRNA expression was assessed by in situ hybridization. Results showed that (1) G93A mice had an elevated basal level of hippocampal neurogenesis for both cell survival and neuronal differentiation, a growth factor (BDNF mRNA), and an oxidative stress marker (NT), as compared to wild type sedentary mice. (2) Treadmill running did not show any further effect on hippocampal neurogenesis, growth factors, oxidative stress, and antioxidant enzymes in G93A mice, while treadmill running promoted hippocampal neurogenes1s and expression of the growth factor (BDNF mRNA), and lowered oxidative stress (8-0Hdg) in WT mice. (3) There also were sex differences in hippocampal neurogenesis in G93A mice, whereby male G93A mice had a significant higher level of cell proliferation but a lower level of survival than female G93A mice. (4) The DG BDNF mRNA was associated with cell survival and neuronal differentiation in sedentary G93A mice, suggesting that BDNF is associated with a higher basal level of hippocampal neurogenesis in G93A mice. We conclude that G93A mice are more permissive in the context of hippocampal neurogenesis, which is associated with elevated DG BDNF mRNA expression. Running did not have impact on hippocampal neurogenesis and BDNF mRNA expression in G93A mice, probably due to a 'ceiling effect' of the already heightened basal levels of hippocampal neurogenesis and BDNF mRNA in this model. In addition, sex differences also affect hippocampal neurogenes1s, but the further study is needed to clarify the underlying molecular mechanisms.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


contributor:
Elbestawi, M.A.
Veldhuis, S.C.
Mechanical Engineering

subject: Accuracy, ultra precision, machining, vibration, workpiece, inaccuracy, aluminum 6061-T6, sufrance finish lobes, disturbance frequencies, broadband, filtering, roughness, surface roughness, roughness curves, filter curves

abstract: This thesis is titled "A Framework for Enhancing the Accuracy of Ultra Precision Machining." In this thesis unwanted relative tool / workpiece vibration is identified as a major contributor to workpiece inaccuracy. The phenomenon is studied via in situ vibrational measurements during cutting and also by the analysis of the workpiece surface metrology of ultra precision diamond face turned aluminum 6061-T6. The manifestation of vibrations in the feed and in-feed directions of the workpiece was studied over a broadband of disturbance frequencies. It is found that the waviness error measured on the cut workpiece surface was significantly larger than that caused by the feed marks during cutting. Thus it was established that unwanted relative tool / workpiece vibrations are the dominant source of surface finish error in ultra precision machining. By deriving representative equations in the polar coordinate system, it was found that the vibrational pattern repeats itself, leading to what are referred to in this thesis as surface finish lobes. The surface finish lobes describe the waviness or form error associated with a particular frequency of unwanted relative tool / workpiece vibration, given a particular feed rate and spindle speed. With the surface finish lobes, the study of vibrations is both simplified and made more systematic. Knowing a priori the wavelength range caused by relative tool / workpiece vibration also allows one to extract considerable vibration content information from a small white light interferometry field of view. It was demonstrated analytically that the error caused by relative tool / workpiece vibration is always distinct from the surface roughness caused by the feed rate. It was also shown that the relative tool / workpiece vibration-induced wavelength in the feed direction has a limited and repeating range. Additionally, multiple disturbance frequencies can produce the same error wavelength on the workpiece surface. Since the meaningful error wavelength range is finite given the size of the part and repeating, study then focussed on this small and manageable range of wavelengths. This range of wavelengths in turn encompasses a broadband range of possible disturbance frequencies, due to the repetition described by the surface finish lobes. Over this finite range of wavelengths, for different machining conditions, the magnitude of the waviness error resulting on the cut workpiece surface was compared with the actual relative tool / workpiece vibrational magnitude itself. It was found that several opportunities occur in ultra precision machining to mitigate the vibrational effect on the workpiece surface. The first opportunity depends only on the feed rate and spindle speed. Essentially, it is possible to force the wavelength resulting from an unwanted relative tool / workpiece vibration to a near infinite length, thus eliminating its effect in the workpiece feed direction. Further, for a given disturbance frequency, various speed and feed rate combinations are capable of producing this effect. However, this possibility exists only when a single, dominant and fixed disturbance frequency is present in the process. By considering the tool nose geometry, depth of cut, and vibrational amplitude over the surface finish lobe finite range, it was found that the cutting parameters exhibit an attenuating or filtering effect on vibrations. Thus, cutting parameters serve to mitigate the vibrational effect on the finished workpiece over certain wavelengths. The filter curves associated with various feed rates were compared. These filter curves describe the magnitude of error on the ultra precision face turned workpiece surface compared with the original unwanted tool / workpiece vibrational magnitude. It was demonstrated with experimental data that these filter curves are physically evident on the ultra precision diamond face turned workpiece surface. It was further shown that the surface roughness on the workpiece surface caused by the feed rate was reduced with relative tool / workpiece vibrations, and in some cases the feed mark wavelength was changed altogether. Mean arithmetic surface roughness curves were also constructed, and the filtering phenomenon was demonstrated over a broadband of disturbance frequencies. It is well established that a decrease in the feed rate reduces the surface roughness in machining. However, it was demonstrated that the improved surface finish observed with a slower feed rate in ultra precision diamond face turning was actually because it more effectively mitigated the vibrational effect on the workpiece surface over a broadband of disturbance frequencies. Experimental findings validated this observation. By only considering the effect of vibrations on the surface finish waviness error, it was shown that the workpiece diamond face turned with a feed rate of 2 {tm / rev has a mean arithmetic surface roughness, Ra , that was 43 per cent smaller than when a feed rate of 10 μm / rev was used.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Towards an Examination of Error Related Neural Processes in Real-World Tasks: ERP Evidence of Uncertainty, Expectancy, Difficulty and Anxiety

contributor:
Shedden, Judith M.
Psychology

subject: human, performance, neural, ERN, CRN, visual, anxiety

abstract: In four experiments I addressed factors that affect human performance monitoring as indicated by neural correlates observed in response-locked event related potentials. Specifically, I examined modulations of the error related negativity (ERN), the correct response negativity (CRN), and the error positivity (Pe) components across a variety of conditions. These components, all thought to be generated in the anterior cingulate cortex, represent activation of the performance monitoring system. Experiments 1 and 2 used stimulus congruency and visual noise to manipulate response and stimulus uncertainty in an extension of previous research. These manipulations, together with a between experiment task manipulation, examined the role of cognitive/attentional load in performance monitoring. Replication of previous findings and a task specific modulation of ERN amplitudes provided support for a role of cognitive load in performance monitoring. Further, these two experiments used a novel task and novel stimuli to replicate previous research and extend our knowledge of how uncertainty affects performance monitoring. In stark comparison to all previous research in this area, Experiments 3 and 4 both employed complex and somewhat ecologically valid tasks. Standard ERN/Pe results in Experiment 3 (touch typing task) revealed that it is possible to examine the ERN in more complex, real world-like tasks. Further, an expectancy manipulation elicited marginal differences in the response-locked Pe but resulted in large N1 and P3 differences suggesting a possible role of attention in early expectation driven performance monitoring adjustments. Experiment 4 examined the role of task difficulty, anxiety level and exposure (i.e., time on task) for effects on ERN and Pe amplitudes. By comparing how math anxious people perform in a math environment, this study represents the first to pit a specific anxiety against a specific anxiety provoking situation. This complex paradigm again replicated general ERN findings providing further support for the validity of complex task usage. Findings surrounding the difficulty manipulation and anxiety measures provide new insight into the role of difficulty in performance monitoring and support the importance of considering personality characteristics in self-regulation.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Overweight And Obesity In Canada: Understanding The Individual and Socio-environmental Determinants

title: Understanding The Determinants of Obesity In Urban Canada

contributor:
Elliott, Susan J.
Geography and Earth Sciences

subject: determinants, overweight, obesity, fat, Canada, geographic variability, health, sex specific spatial,spatial clusters, geographical information system, GIS, spatial analysi

abstract:
 This research examined the geographic variability as well as the individual-and neighbourhood-level determinants of overweight and obesity in Canada. Overweight and obesity represent a significant public health problem with grave implications for individuals as well as populations. Over the past two decades, the prevalence of overweight and obesity has reached epidemic proportions with the most substantial increases observed in economically developed countries. The World Health Organization indicated that globally 1.6 billion adults (age 15+) are overweight and at least 400 million adults were obese. In a Canadian context, recent data from Statistics Canada confirms that over the past twenty-five years, adult obesity rates in Canada have doubled (23% ), while childhood obesity rates have nearly tripled.

 Until recently, research has focused on biological and behavioural determinants of obesity, and currently there is a great deal of knowledge regarding the relationships between weight status and various risk factors at the individual-level (e.g. age, sex, socioeconomic deprivation, diet, physical activity). However, the majority of existing research has ignored the potential role played by the environment in the development of these conditions, despite a growing consensus that environmental and/or societal constraints may be major influences on increasing prevalence rates.

 Using data from the Canadian Community Health Surveys and the Desktop Mapping Information Technologies Incorporated spatial database, this research addressed the following objectives: (I) to examine sex-specific spatial patterns of overweight/obesity in Canada as well as investigate the presence of spatial clusters (2) to investigate the prevalence and determinants of overweight and obesity in Canada using spatial analysis and geographical information systems (GIS) and (3) to identify heterogeneities associated with the relationships between individual and socioenvironmental determinants and overweight and obesity at the individual-and community-levels.

 Results revealed marked geographical variation in overweight/obesity prevalence with higher values in the Northern and Atlantic health-regions and lower values in the Southern and Western health-regions of Canada. Significant positive spatial autocorrelation was found for both males and females, with significant clusters of high values or 'hot spots' of obesity in the Atlantic and Northern health-regions of Alberta, Saskatchewan, Manitoba and Ontario. Results also demonstrate the important role of the built-environment after adjustment demographic, socio-economic and behavioural characteristics. With regard to the built environment measures, landuse mix and residential density were found to be significantly associated with BMI. This study also demonstrated significant differences at the area-level of analysis, supporting related research that has suggested that individual-level factors alone cannot explain variation in obesity rates across space. In particular, average dwelling value was related to BMI independently of individual-level characteristics. Ultimately, this research has demonstrated that Canadian urban environments play a small but significant role in shaping the distribution of BMI. Yet, reversing current trends will require a multifaceted public health approach where interventions are developed from the individual-to the neighbourhood-level, specifically focusing on altering obesogenic environments.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Psychophysical Properties of Perceived Vocal Attractiveness Based on Pitch Manipulations

contributor:
Feinberg, David R.
Psychology

subject: manipulations, vocal, pitch, psychophysical, frequency, attractiveness

abstract:
 Experiments have shown that manipulations of vocal fundamental frequency, a physical correlate of voice pitch, alter perceptions of vocal attractiveness. Individual experiments, however, have found different effects of pitch manipulations on attractiveness. One possible explanation for the disparate findings may be differences in the strength of pitch manipulations used between studies. The focus of this thesis is to determine psychophysical properties of vocal attractiveness based on pitch manipulations. Within the thesis, two experiments are described that were designed to find just-noticeable differences in vocal attractiveness based on pitch manipulations. The experiments were also designed to determine if there are limits for voice pitch preferences. Relevant background concepts to the thesis are described in Chapters 2-5, and a manuscript is presented in Chapter 6 that describes the methods and results of the experiment, and gives a discussion of the findings.

 In Chapter 2, the basic anatomy underlying vocal production is explained, including the anatomical structures involved in the source-filter model of vocal production.

 In Chapter 3, relevant acoustic properties of the voice are described, including fundamental frequency, harmonics, and formant frequencies.

 In Chapter 4, the basic anatomy involved in audition is explained, including how sound is propagated through the ear.

 In Chapter 5, a brief review of previous psychophysical research on pitch discrimination and perceived vocal traits is given.

 In Chapter 6, two experiments are described. Experiment 1 was designed to determine just-noticeable differences in voice pitch discrimination. Experiment 2 was designed to determine just-noticeable differences in voice attractiveness based on manipulations of voice pitch. Experiment 2 was also designed to assess potential limits to voice pitch preferences for supernormal stimuli. Just-noticeable differences in vocal attractiveness were larger than just-noticeable differences in pitch discrimination. Just-noticeable differences in attractiveness were larger in women's voices than men's. There was no limit in men's preferences for highpitched voices, however there was a limit for women's preferences for low-pitched voices below the natural male pitch range.

abstract: Thesis

abstract: Master of Science (MSc)


title: An Anatomy of the Soul In English Renaissance Religious Poetry

title: An Anatomy of the Soul

contributor:
Silcox, Mary V.
English

subject: soul, body, soul-body relationship, identity, religous poetry, Christianity, moderns, anatomy, An Collins, Francis Quarles, meditiations, religion

abstract: This dissertation examines the centrality of the soul-body relationship to the construction of identity in English Renaissance religious poetry. The expanding field of 'body criticism' has greatly increased our understanding of the early modern body, but critics have rarely considered how Christianity influenced the ways the early moderns thought about their bodies and their embodied souls at a time when the science of anatomy flourished in Europe. Consequently, our current perception of the early modern subject is skewed. This dissertation addresses this critical gap by exploring the persistence of Christian narratives in discussions of both the body and the soul throughout the sixteenth and seventeenth centuries. The first two chapters address two interrelated question: how did early modern anatomists understand the soul, and how did early modern religious writers understand the body? This dissertation begins by examining the religious perspectives that are evident in English anatomical writing and then moves on to explore the presence of anatomical perspectives in English religious writing on the soul in order to discuss the intimate relationship between corporeality and spirituality. The final two chapters focus on the devotional poetry of An Collins and the devotional emblems of Francis Quarles in order to demonstrate the integration of a Christianized sense of corporeality into meditations on religious subjectivity. Both writers draw on the issues discussed in the first two chapters but represent corporeality differently. On the one hand, Collins transforms physical suffering into a sign of her salvation. On the other hand, Quarles expresses anxiety over the world's ability to infect the soul through the body. In both cases, the relationship between body and soul is a central concern, and their representation of that relationship is indebted to a Christianized sense of embodiment.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Secure and Trusted Verification

contributor:
Karakostas, George
Wassyng, Alan
Computing and Software

subject:
Verification
Tabular expressions

abstract:
In our setting, verification is a process that checks whether a device's program (implementation) has been produced according to its corresponding requirements specification. Ideally a client builds the requirements specification of a program and asks a developer to produce the actual program according to the requirements specification it provides. After the program is built, a verifier is asked to verify the program. However, nowadays verification methods usually require good knowledge of the program to be verified and thus sensitive information about the program itself can be easily leaked during the process.

In this thesis, we come up with the notion of secure and trusted verification which allows the developer to hide non-disclosed information about the program from the verifier during the verification process and a third party to check the correctness of the verification result. Moreover, we formally study the mutual trust between the verifier and the developer and define the above notion in the context of both an honest and a malicious developer.

Besides, we implement the notion above both in the setting of an honest and a malicious developer using cryptographic primitives and tabular expressions. Our construction allows the developer to hide the modules of a program and the verifier to do some-what white box verification. The security properties of the implementation are also formally discussed and strong security results are proved to be achieved.

abstract: Thesis

abstract: Master of Science (MSc)


title: COOKING UP A NATION: PERCEPTIONS OF ENGLISH COOKERY, 1830-1930

contributor:
Heathorn, Stephen
History

subject: British history, cookery, identity

abstract:
This dissertation explores the origin of the idea that English food is inherently “bad” and demonstrates that this perception developed in the mid-nineteenth century.  While it is commonly assumed that the poor quality of English cookery developed after the Second World War, this dissertation demonstrates that English cookery was perceived poorly beginning in the nineteenth century.  This dissertation brings together an analysis of Victorian values, gender, food adulteration, food technologies, and nostalgia to establish how the English criticized themselves and created the belief that English cookery is “bad.”  By examining cookbooks and newspaper articles, this investigation illustrates how the English criticized their own cooking and developed a sense of anxiety about their perceived flawed cookery.  In the nineteenth century, cookery was evaluated based on emerging Victorian moral values rather than taste.  The emphasis on being economical, efficient, and clean meant that traditional English dishes such as roast beef and plum pudding were no longer celebrated, but instead, considered wasteful and monotonous.  Increasing imports through advances in shipping, refrigeration, and canning decreased the production of English goods at home.  The adaptation and absorption of new imported ingredients and dishes into English cookbooks created a cosmopolitan cookery by the twentieth century, but, at the same time, deepened confusion over what an English food identity was.
	By studying cookbooks, this dissertation uses an untapped resource to explore the perception of English cookery.  Cookbooks, especially mass publications, helped further the belief that English cookery was wasteful and unclean, and prescribed countless remedies for readers.  Cookbooks also offered another perspective for exploring gender and cookery, as middle class women found themselves multitasking as housewives, educators, and cooks.  More than just a collection of recipes, cookbooks provide historians with windows to view ideas of food identity, community, and culture.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Capacity and Signaling for Free-Space Optical Channels

contributor:
Hranilovic, Steve
Electrical and Computer Engineering

subject: wireless, optical, communication, channel, capacity, beamwidth,

abstract:
 Wireless optical communication systems have the potential of establishing secure high
data rate communication links. In order to realize the ultimate promise of these links,
channel modeling and communication algorithms must be developed. This thesis
addresses free-space optical (FSO) system design and provides novel contributions
in four major areas: 1) channel modeling, 2) channel capacity and optimal signal
design, 3) signaling algorithms, and 4) formal methods to jointly design code rate
and beamwidth for FSO systems.

 A novel statistical channel model taking into account atmospheric and misalignment fading is developed that generalizes the existing models and accounts for transmitter beamwidth. The channel capacity is analyzed under average and peak optical power constraints and a new class of non-uniform discrete input distributions are developed with mutual information that closely approaches the channel capacity. Algorithms to realize the proposed non-uniform signaling and achieve the promising
rates are also presented. Numerical simulations are conducted with finite length low
density parity check codes showing significant improvement in system performance.
Finally, the developed signaling is applied to FSO channels considering the above
impairments. Beamwidth optimization is considered to maximize the channel capacity
subject to outage. It is shown that a rate gain of 80% can be achieved with
beamwidth optimization.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Task-specific modulation of corticospinal excitability during arm and finger movements

contributor:
Nelson, Aimee Jennifer
Kinesiology

subject:
Transcranial Magnetic Stimulation
Clinical Neurophysiology
Neural Control of Movement
Somatosensory-motor integration
Primary Motor Cortex
Primary Somatosensory Cortex
Cortical Circuitry
Task-dependent Cortical Output

abstract: The main goal of the dissertation was to determine task-dependent modulation of corticospinal descending output.  From this main goal, I conducted three different studies to determine how corticospinal output to muscles of the upper arm and hand changed as a function of the task demands.  In study 1, I examined how a somatosensory-motor circuit changes when a muscle needs to be active in a task and found that this circuit may be dependent on the movement phase, type of afferent input, and the task demands.  In study 2, I examined how this same somatosensory-motor circuit acts to both allow and prevent muscle activity before movement.  I revealed that this somatosensory-motor circuit may function to prevent muscle activity when a muscle is not needed in a task and creates facilitation of corticospinal output when it needs to be active in a task.  These effects, however, are dependent on the movement phase and the digit the muscle is controlling.  Study 3 determined how corticospinal output is modulated to upper arm muscles when performing movements that required different combinations of segmental interactions to achieve the task successfully.  Corticospinal output was increased when inertia and the BBC moment at a joint resisted the intended joint rotation and these effects were dependent on the muscle and movement phase.  I propose a model of the connectivity between the primary motor and somatosensory cortices that would increase, modulate, or decrease corticospinal output to a muscle depending on its role in the task.  The findings from this work provides information to guide future neural rehabilitative interventions for individuals who have movement disorders arising from altered somatosensory-motor processing such as Cerebellar Ataxia, Developmental Coordination Disorder, Focal Hand Dystonia, Parkinson’s disease, and stroke.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: On a day to day basis, we perform a variety of movements without giving much thought to how complicated it is for our nervous system to perform said movements.  There are many different areas of the brain that are responsible for controlling movement.  This dissertation focuses on two key areas that are critical for movement performance, namely the primary motor and somatosensory cortices.  The primary motor cortex is largely responsible for sending signals to the muscles to control movement, while the primary somatosensory cortex plays a crucial role in receiving and understanding sensory input from our body.  The studies in this dissertation describe how these two areas of the brain communicate during finger and arm movements to produce or prevent muscle activity.  This work has implications for individuals with disorders that impact their everyday movements.


title: New Chiral Phosphonates for Organocatalysis and Isolation and Chemical-Biology of Natural Products from Ontario Plants

contributor:
McNulty, James
Chemistry

subject: catalytic, carbonyl, chiral, organocatalyst, phosphonates, plants

abstract:
 The catalytic asymmetric transformation of carbonyl compounds via iminium and enamine intermediates using chiral amines as organocatalyst has grown remarkably over last decade. Various "metal-free" reactions including aldol, Mannich, Michael, alkylation and Knoevenagel types have now been reported efficiently using simple amino acids as the sole organocatalysts. Amongst these, proline has proven to be particularly useful as a general catalyst in such catalytic asymmetric syntheses due to its unique properties. Nonetheless, proline suffers inherent fundamental disadvantages as an organocatalyst in terms of its solubility in organic media, limiting reactions to polar aprotic solvents such as DMF or DMSO. We have been interested in the synthesis of derivatives of proline incorporating functional groups that would render the chiral secondary amine fully soluble in organic solvents such as THF or dichloromethane and others that could be employed in aqueous media. The synthesis of these catalysts and their application towards the asymmetric synthesis will be presented.

 The thesis also describes isolation and identification of natural products and synthesis of their semi-stabilised derivatives. Sakuranetin and dihydrowagonine were isolated from Prunus avium plant parts, menisadurilide was isolated from Dicentra spectabilis extracts while narciclasine was isolated from Narcissus pseudonarcissus plant parts. Semi-synthetic derivative, trans-dihydronarciclasine was prepared from natural product narciclasine. Both the derivatives were subjected to antifungal and human cytochrome inhibition activity and their correlation is explained. The Amaryllidaceae family alkaloids and their semi-synthetic derivatives were subjected to biological testing and an important structural property is correlated to their activities.

abstract: Thesis

abstract: Master of Science (MSc)


title: Social Learning About Egg-Laying Sites in Drosophila Melanogaster

contributor:
Dukas, Reuven
Psychology

subject: social, learning, fruit fly, egg, laying, food, mated,

abstract: Social learning, defined as learning from other individuals has been well studied in vertebrates and social insect species. I used fruit fly egg laying site selecting as a paradigm to test for social learning in a non-social insect. Focal females that experienced novel food together with mated females (models), who had laid eggs on that food, subsequently exhibited a stronger preference for laying eggs on that food over another novel food than focal females that experienced the same food alone. This socially influenced learning was also observed when focal females experienced both foods, one with mated models and their eggs and one alone. In contrast to the strong effect of a food with mated models and their eggs, neither a food with virgin models nor the aggregation pheromone (cVA) alone generated socially influenced learning. These results provide the first evidence for social learning about egg laying substrate in fruit flies. Further research utilizing fruit flies as a model system may help us gain a better understanding of the evolution and neurogenetics of social learning.

abstract: Thesis

abstract: Master of Science (MSc)


title: Pricing and Inventory Models for a Retailer

contributor:
Abad, Prakash L.
Hassini, Elkafi

subject: pricing, inventory, retail, supply, demand, profit, charges

abstract:
 In this thesis we study three problems of joint pricing and inventory in a retail setting.

 The first problem deals with pricing and ordering for a retailer facing uncertain supply as well as price-sensitive uncertain demand. We first formulate the problem as two cases of pricing: a simultaneous pricing strategy where the price and the order quantity are simultaneously determined and a postponed pricing strategy where the price and the order quantity are sequentially determined. We provide a solution procedure to find the optimal price and order quantity that maximizes the retailer's profit. By conducting sensitivity analysis, we find that if the supplier is very unreliable, then the retailer is better off postponing the pricing decision in order to maximize profit. Reducing supply variability does not have the same impact on retailer's profit as much as increasing the expected supply amount. Most importantly we find that the difference between the expected profits in the two cases is not due to higher expected revenue, but due to lower expected salvage and shortage losses when the pricing decision is postponed.

 Next, we study a price setting retailer selling two substitutable goods to consumers. The retailer must decide on the optimal price and inventory that maximize the expected profit. Aside from making these decisions under demand uncertainty, the retailer must also account for the substitution that occurs upon stock out of one of the two products. Furthermore, we also take into account the related cannibalization of the available stock due to customers substituting. We formulate the problem and find the optimal prices analytically as well as conduct sensitivity analysis. We compare our findings to a model that does not consider substitution and the resultant cannibalization of inventory and find that the model that does not consider substitution tends to overestimate the expected profit for low degrees of substitution and tends to underestimate the expected profit for high degrees of substitution. Furthermore, the prices charged and the inventory held at the retailer for each product, tend to be suboptimal. The total quantity stocked in general, for both products, is lower when we account for substitution and cannibalization.

 Lastly, we study the problem of finding optimal order quantities and prices for the bundle (a collection of two or more goods sold jointly at one price) and individual items as well as how a supplier can use bundles to achieve coordination with its retailer. In a decentralized supply chain, we show that bundling is not always a feasible or a very profitable strategy. This is especially true if the products or the bundle are discounted beyond a certain point, because it may make the supplier worse off while making the retailer better off. This reduces the effectiveness of the bundling strategy in a supply chain setting. We find that the supplier, retailer and the supply chain can simultaneously improve their profits by offering bundled goods to the consumers and achieve performance of a coordinated supply chain when the supplier charges the retailer a bundling fee upfront and in exchange offering a bundling discount to the retailer.

 In the last chapter, we summarize our findings as well as provide direction for future research.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Planning and Scheduling Optimization in the Steel Industry

contributor:
Swartz, Christopher L. E.
Chemical Engineering

subject:
Optimization
Production Planning
Scheduling
Steel

abstract:
Production planning is a critical component in supply chain management. The goal of production planning is to meet market demand while minimizing operational costs. There is inherent uncertainty in manufacturing systems due to unscheduled shutdowns and variable production rates. Additionally, actual demand levels cannot be predicted accurately. As a result, there is value in creating a production plan that considers these uncertainties.

Scheduling is also a critical component in supply chain management, but at a smaller level of time granularity. Industrially sized scheduling problems are often on such a large scale that the problem is computationally difficult to solve. Consequently, there is value in creating a mathematical model and selecting a solution algorithm that minimizes this burden.

This work aims to determine the benefit of a stochastic production planning model over its deterministic counterpart. The problem utilizes a multi-period, multi-product aggregated planning model with a finite horizon in a steel manufacturing environment. The production and demand uncertainty is modelled as a two-stage stochastic mixed integer linear program. The problem utilizes a Monte Carlo simulation technique to create the scenarios used in the optimization. The objective of the optimization is to determine the production volume and inventory levels for each discrete time interval while minimizing the weighted cost of production and surplus. The production decisions must be non-anticipative, immediately implementable, and are subjected to production capacity and inventory holding constraints. This work also investigates the advantages a cost-based model has over its goal-programming counterpart. Finally, this thesis develops several mathematical batch scheduling models that use different modelling paradigms in an effort to compare their computational complexity. With the selection of an appropriate model, model extensions are added to replicate an industrially relevant steel mill scheduling problem for a finishing line using data from a facility located in Ontario, Canada.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: New Advances in Joint Source-Channel and Multiple Description Coding

contributor:
Wu, Xiaolin
Dumitrescu, Sorina
Electrical and Computer Engineering

subject: joint, source-channels, coding, description, signal, networks

abstract:
 This thesis launches some new inquires and makes significant progress in the active
research areas of joint source-channel coding and multiple description coding. Two
interesting but previously untreated problems are investigated and partially settled:
1) can index assignment of source codewords be optimized with respect to a given
joint source-channel decoding scheme, and if so, how? 2) can joint source-channel
coding be optimized with respect to a given multiple description code, and if so,
how?

 The first problem is formulated as one of quadratic assignment. Although quadratic assignment is NP-hard in general, we are able to develop a near-optimum index assignment algorithm for joint source-channel (JSC) maximum a posteriori (MAP)
decoding, if the input is a Gaussian Markov sequence of high correlation. For general
cases, good heuristic solutions are proposed. Convincing empirical evidence is
presented to demonstrate the performance improvement of the index assignments
optimized for MAP decoding over those designed for hard-decision decoding.

 The second problem is motivated by applications of signal communication and estimation in resource-constrained lossy networks. To keep the encoder complexity at a minimum, a signal is coded by a multiple description quantizer (MDQ) without channel coding. The code diversity of MDQ and the path diversity of the network are exploited by decoders to combat transmission errors. A key design objective is resource scalability: powerful nodes in the network can perform JSC-MD estimation under the criteria of maximum a posteriori probability or minimum mean-square error (MMSE), while primitive nodes resort to simpler multiple description (MD) decoding, all working with the same MDQ code. The application of JSC-MD to distributed estimation of hidden Markov models in a sensor network is demonstrated. The proposed JSC-MD MAP estimator is an algorithm of the longest path in a weighted directed acyclic graph, while the JSC-MD MMSE decoder is an extension of the well-known forward-backward algorithm to multiple descriptions. They outperform the existing
hard-decision MDQ decoders by large margins.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Police Inadequacy and the Space of the City in British Fin de siècle Literature

contributor:
Kehler, Grace
English

abstract: This thesis examines the representation of police in late-nineteenth and early-twentieth century British literature. My analysis focuses on the relations between the subjects of the texts, as well as the texts themselves, and the institution of the police. I develop an understanding of the police as a compromised force of bureaucratic adjuncts who, in the conception of these Victorian texts, possess a troubling power over the bodies and spaces of British citizens. I discuss the multifarious anxieties about imperial and national decline during the period, and show how in all of my primary texts fears about the loyalties and effectiveness of police run parallel to fears for more traditionally Victorian modes of social control, such as class, charity, and the family. Also I examine the built space and social environment of fin de siècle London as it is constructed in these texts and show how they figure the capital as a space of alienation, danger, and degeneration. The combined investigation of the space and those who police it reveals serious concerns about justice and identity as meted out by an often-impersonal but increasingly interventionist state. The projects seeks to contribute to a larger cultural history of the police in order to better understand that institution which orders and arbitrates so much of modern life, and also seeks to articulate some of the concerns raised during the development of the modern welfare state.

abstract: Thesis

abstract: Master of Arts (MA)


title: Temperament and Joint Attention: Stability, Continuity and Predictive Outcome in Children's Socioemotional Development

contributor:
Schmidt, Louis A.
Psychology

subject:
temperament
mother-child interactions
socioemotional outcome
low-risk children
joint attention
Internalizing Behaviour Questionnaire
internalizing behaviours

abstract:
Past research has focused extensively on the influence of temperament and mother-child interactions for the development of psychopathology. However, there is a paucity of research that has examined the role of natural variations in temperament and mother-child interactions on socioemotional outcome in samples of low-risk typically developing children. Furthermore, most research has investigated temperament and mother-child interactions in separate studies. Accordingly, the present work addressed three issues: 1) the short-term and long-term continuity of temperament and joint attention in typically developing children; 2) the predictive value of temperament and joint attention for socioemotional outcome in typically developing children; and 3) joint attention behaviours in a clinical sample of children.
Temperament was assessed through maternal report on the Infant Behavior Questionnaire (IBQ) beginning when children were between 18 and 3 7 months of age while joint attention was assessed through direct observation. All the IBQ subscales showed 9-month continuity and 4 of the 6 IBQ subscales showed moderate to high stability. Although there was 9-month continuity for all the joint attention measures, only 4 out of the 7 joint attention behaviors showed low to moderate levels of stability. There was little 4-year continuity or stability of temperament. Cross-sectional relations were found between temperament and socioemotional outcome at both 18 and 37 months of age as well as 69 and 88 months of age. Established joint attention, measured when children were between 18 and 37 months of age, significantly predicted internalizing behaviours in typically developing children between the ages of 69 and 88 months. Significant differences in joint attention were also found in a clinical sample of children with internalizing disorders between the ages of 5 and 8 years. The present results suggest that some ofthe same temperament and joint attention behaviours that are associated with atypical development are also associated with typical variations in socioemotional development.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Linewidth and Hyperfine A Constant of the 2P1/2 State of a Magnesium Ion Confined in a Linear Paul Trap

contributor:
King, Brian
Physics and Astronomy

subject:
hyperfine a constant
natural linewidth
magnesium ion

abstract: We present and discuss results from a measurement of the hyperfine a constant of the 1s^(2)2s^(2)2p^(6)3p^(2)2P1/2 excited state in 25Mg+ and the linewidth of the same state in 24Mg+. We trapped a single ion in a linear Paul trap and laser-cooled it using the 2S1/2 -> 2P3/2 transition (in the case of 25Mg+) and the 2S1/2 -> 2P1/2 transition (in the case of 24Mg+). We optically pumped the ion into the (F=3, mp=±3) ground states and weakly probed it with a tunable fibre laser that was scanned to drive the ion from the ground state to the F'=3 and F'=2 manifolds of the 2P1/2 state. The final state of the ion was determined by counting fluorescence (or the reduction therein) from the 2S1/2 (F=3, mF=±3) -> 2P3/2 (F''=4, m''F=±4) cycling transition with a photomultiplier module. We determined that the hyperfine a constant is 102.16 ± 0.16 MHz and the natural linewidth is 42.4 ± 1.2 MHz.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Structural and Transport Properties of Epitaxial Niobium-Doped BaTiO3 Films

contributor:
Botton, Gianluigi
Preston, John S.
Materials Science and Engineering

subject: BaTi, thin films, substrates, conductivity, epitaxy, electron, energy

abstract: Highly orientated BaTi1-xNbx03 thin films, spanning the entire range of x, have been successfully deposited on (001) MgAl20 4 substrates by the pulsed laser deposition (PLD) method. The structure of the films is characterized with a range of techniques. It is found that increasing x gives rise to a Ti4+ to Ti3+ transformation in the oxidation state accompanied by increased conductivity with a semiconductormetal transition near x = 0.2. Temperature dependent magnetic measurements show an anomalous rise in the spin moment. In order to further reduce the lattice mismatch and keep the conductivity at the same time, a partial strontium-for-barium substitution, (Ba1-ySry)Ti0.5Nb0.5O3 withy = 0, 0.4, 0.5 and 0.6, were used. Such a substitution provides a means for independently tuning the lattice parameter and conductivity over a significant range of compositions. The y = 0.6 composition show a sharp interface with flawless epitaxy and good quality films. We attribute the improvements in the film quality to a decrease in the lattice misfit strain made possible through the superior lattice match to the substrate obtained through strontium substitution. Electronic structure calculations were carried out by the 1st principle method using the WIEN2k program in order to understand the electronic structure of these compounds. Based on the assumed ordered structures, the Fermi level of BaTi1-xNbxO3 gradually moved to the lower energies as x increase, while the valence bands were not significantly altered with the Nb ions substitutions. The fraction of each Ti4+ and Ti3+ component in BaTi1-xNbxO3 samples was extracted by the linear profile fitting of the corresponding Ti-L2,3 edge obtained by the electron energy loss spectra. The fitting results indicate a high fraction of Ti3+ is present than excepted as Nb content increase, which could arise from the loss of oxygen stoichiometry. The electron energy loss spectra of the 0-K edge is analyzed by comparison to the partial density of states calculation. The evolutions of 0-K edge features are explained in terms of the decrease of the Ti 3d band contribution and the increase of the Nb 4d band contribution as the Nb content increase.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Characterization of the Mucosal and Systemic Immune Responses Following Virus Vector-Based Gene Delivery into the Colonic Mucosa

contributor:
Gauldie, Jack
Biochemistry

subject: mucosal and systemic T-cell responses

subject: CD8+ T cells

subject: adenovirus vector Gallus gallus ovalbumin

subject: immunization

subject: vaccination

subject: cell population

subject: protein expression

subject: lentiviral vectors

subject: booster vaccine

abstract: While adenovirus (Ad) vectors have been shown to elicit potent antigen-specific T cell responses, the kinetics and nature of antigen-specific mucosa! and systemic T-cell responses has rarely been examined, especially following mucosal administration of Ad-based vectors. In the present studies, the phenotypic and functional characterization of antigen-specific CD8+ T cell responses following intrarectal (i.r.) vaccination with an Ad vector expressing Gallus gallus ovalbumin (OVA) was conducted. The frequencies of OVA-specific CD8+ T cells was maximal at 2 weeks post-vaccination in all tissues examined and then declined, demonstrating normal expansion and contraction kinetics. CD8+ T cells induced in the course of immunization exhibited phenotypic characteristics of effector memory T cells including up-regulation of the cell surface molecules CD43, CD44 and a low level of expression of CD127 at both local and systemic sites. While the discordance between the number of tetramer-reactive and cytokine-producing OVA-specific CD8+ T cells was observed, CD8+ T cells appeared to be fully functional in vivo. Upon secondary antigen exposure, the CD8+ T cell population expanded dramatically, particularly at the mucosa! surfaces. In addition, the CD8+ T cell response generated in the course of i.r. priming protected mice from intravaginal (i. vag.) vaccinia virus one month after immunization, thus underscoring the importance of inducing a tissue-resident effector memory T cell subset for protection against pathogens at mucosal surfaces. In developing future vaccines for mucosal diseases, the induction of a tissue-resident effector memory T cell subset should be one of the immunization objectives. Lentiviral vectors represent an attractive mode of genetic vaccination. Most commonly used, vesicular stomatitis virus glycoprotein (VSVG)-pseudotyped lentiviral vectors do not efficiently infect epithelial cells from the apical side, and, therefore, are not suitable as mucosa! vaccines. In the present studies, Ebola Zaïre strain glycoprotein (EboZ)-pseudotyped lentiviral vectors, which have been previously used to deliver transgene to the lung epithelium, were delivered i.r. and evaluated as a mucosal booster vaccine. Rectal delivery of EboZ-pseudotyped lentiviral vectors expressing β-galactosidase (β-gal) had resulted in low, but detectable levels of β-gal expression 2 weeks after administration. When delivered on its own, EboZ-pseudotyped lentivirus did not prime detectable antigen-specific immune response. However, when delivered i.r. 30 days after i.r. Adβ-gal immunization, a significant enlargement (boost) of β-gal-specific CD8+ T cell responses, especially in the colonic lamina propria (LP), was observed as compared to the delivery of EboZ-pseudotyped vector encoding different transgenes or VSVG-pseudotyped lentivirus expressing β-gal. When these animals were i. vag. challenged with vaccinia virus expressing β-gal, a dramatic expansion of β-gal-specific CD8+ T cells, especially in the vaginal tract, was observed. In addition, this prime and boost strategy protected the mice from i. vag. vaccinia virus challenge. Therefore, i.r. Ad-based priming followed by i.r. EboZ-pseudotyped lentiviral boosting was an effective strategy for eliciting protective mucosal CD8+ T cell responses.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The role of Reynolds number in the fluid-elastic instability of cylinder arrays

contributor:
Kevlahan, Nicholas
Computational Engineering and Science

subject:
fluid structure interaction
fluid elastic instability
Reynolds number
high performance and parallel computing
Cylinder array

abstract:
The onset of fluid-elastic instability in cylinder arrays is usually thought to depend primarily on the mean flow velocity, the Scruton number and the natural frequency of the cylinders. Currently, there is considerable evidence from experimental measurements and computational fluid dynamic (CFD) simulations that the Reynolds number is also an important parameter. However, the available data are not sufficient to understand or quantify this effect. In this study we use a high resolution pseudo-spectral scheme to solve 2-D penalized Navier-Stokes equations in order to accurately model turbulent flow past cylinder array. To uncover the Reynolds number effect we perform simulations that vary Reynolds number independent of flow velocity at a fixed Scruton number, and then analyze the cylinder responses. The computational complexity of our algorithm is a function of Reynolds number. Therefore, we developed a high performance parallel code which allows us to simulate high Reynolds numbers at a reasonable computational cost.
The simulations reveal that increasing Reynolds number has a strong de-stabilizing effect for staggered arrays. On the other hand, for the in-line array case Reynolds number still affects the instability threshold, but the effect is not monotonic with increasing Reynolds number. In addition, our findings suggest that geometry is also an important factor since at low Reynolds numbers critical flow velocity in the staggered array is considerably higher than the in-line case. This study helps to better predict how the onset of fluid-elastic instability depends on Reynolds number and reduces uncertainties in the experimental data which usually do not consider the effect of Reynolds number.

abstract: Thesis

abstract: Master of Science (MSc)


title: An Investigation into the Motion Cues Eliciting a Perception of Animacy

contributor:
Rutherford, Mel
Psychology

subject: perception, animacy, speed, motion, object

abstract:
 The perception of animacy - judging an object as appearing alive - is a
fundamental social perception dating back to Piaget. The present research
investigates motion to examine how and when people will perceive an ambiguous
moving object as appearing alive.

 Chapter 1 uses a number of methods to illustrate that people will judge a relatively faster-moving object as appearing alive more often than an identical but relatively slower-moving object. Chapter 2 demonstrates that people are more
likely to perceive an object moving at a constant speed if it appears to move
relatively faster than a similar object. Further, people will make this judgement
even if the differences in speed are not real, but merely illusory.

 Chapter 3 describes a specific case where the association of greater speed
and animacy is not perceptually maintained. By showing people objects that
appear to fall or rise - thereby obeying or violating gravity - it is shown that our
perceptions of animacy are not fixed, but rather are functionally adapted to at least
one regular and predictable feature of the visual environment; namely gravity.
This suggests that some aspects of our perceptions of animacy have been shaped
over evolutionary time.

 The following chapter examines whether our perceptions of animacy are structured - like our perceptions of colours - categorically, such that there is an
identifiable boundary between the velocities that elicit a perception of animacy
and the velocities that do not. Results suggest that people do not perceive animacy
categorically

 The final empirical chapter illustrates that experience over the lifespan
also influences our perceptions of animacy and of speed. Monolingual readers of
a language read from left-to-right (viz., English) were biased to judge an object
moving in that direction as appearing faster and more alive than an object moving
at the same speed in the opposite direction. However, bilingual readers of both
English and a language read from right-to-left did not exhibit this bias.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Toxic Talk at Walpole Island First Nation: Narratives of Pollution, Loss of Resistance

contributor:
Herring, D. Ann
Nicks, Trudy
Darnell, Regna
Anthropology

subject:
environmental health
Walpole Island First Nation
risk analysis
risk perception
chemophobia
water quality
grounded theory
medical anthropology
collaborative research anthropology

abstract:
This narrative ethnography is based on seven years of research collaboration with the Walpole Island First Nation (WIFN). The study focuses on local perceptions of risk as they relate to ecosystem integrity, human health and well-being. Discourse analysis of generic and nuanced community narratives reveals diverse yet complementary situated knowledge that are firmly rooted in Anishinaabeg (Ojibwe) cultural teachings, values and practices. Gerald Ryle and Clifford Geertz's conceptualization of thin and thick description is used to parse out the various components of what I've identified as a community genre of toxic talk. Within this model, thin description refers to observations of the surface metamorphoses of the physical environment through pollution and other anthropogenic changes. Thick description emerging from the analysis of elegies and echoes of loss and discourses of resistance illuminates the discursive tactics employed by community members to resist Western frameworks of risk analysis and re-situate the topic of environmental health within the wider interpretive matrix of structural violence.
A proposed Shell refinery expansion project is used as an example of how WIFN actively mobilizes discourses via oral tradition in the struggle for environmental justice. Through the strategic use of toxic talk, the community draws attention to environmental issues while simultaneously laying bare to a wider, non-Native audience the historical scaffolding of Native issues that are part and parcel of contemporary environmental crises and their effective mediation and resolution. The 'discursive movement' from elegies and echoes of loss to discourses of resistance reframes Walpole Island residents from those who are defined by survivorship to those who embody and evoke a spirit of survivance. The dissertation concludes with a semiotic critique of the Western medical terms chemophobia and risk perception. This leads to the advancement of toxic talk as an alternative framework for acquiring a more politicized, historicized and humanized understanding of environmental concerns at Wal pole Island.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Assessment and feedback in surgical training

contributor:
Sonnadara, Ranil
Health Science Education

subject:
Surgical education
Medical education
Assessment
Feedback
Residency
Competency-based medical education

abstract: This thesis investigates problems with current assessment and feedback practices in surgical training, and proposes ways to mediate some of these issues. In the first study, we report a number of barriers that might prevent supervisors from providing constructive feedback to medical trainees, including a fear of being labeled as intimidating or harassing. We also identify some barriers which make it challenging for supervisors to accurately report the progress of underperforming trainees including insufficient documentation, a perceived lack of support from program leadership, insufficient opportunities to observe performance, competing demands on time, fear of appeals or legal action, and fear of reciprocated poor staff evaluations. The second study examines the effectiveness of two new tools for assessing trainees’ performance and determines that these tools might be helpful in overcoming some of the barriers identified in the first study to help supervisors provide more meaningful feedback to trainees. Participants reported that the new tools were helpful for improving learning in six ways: by sparking a dialogue regarding performance; by promoting a structured, procedure-specific framework which could be used as a mechanism for providing high quality feedback; by providing a framework for directing future learning; by facilitating a systematic tracking of progress over time; by promoting an increased motivation to learn; and by introducing a learning focus to the intraoperative environment. Together, the data from this thesis provide us with a better understanding of how we might improve the use of assessments and feedback in surgical training. The hope is that our findings will improve the education of new physicians and ultimately improve patient care.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: This thesis investigates problems with current assessment and feedback practices in surgical training, and proposes ways to mediate some of these issues. We present two studies. In the first, we explore barriers that might prevent supervisors from providing constructive feedback to medical trainees. We also identify some barriers which make it challenging for supervisors to accurately report the progress of underperforming trainees. The second study examines the effectiveness of two new tools for assessing trainees’ performance and demonstrates that these tools might be helpful in overcoming some of the barriers identified in the first study to help supervisors provide more meaningful feedback to trainees. Together, the data from this thesis provide us with a better understanding of how we might improve the use of assessment and feedback in surgical training. The hope is that our findings will improve the education of new physicians and ultimately improve patient care.


title: Genetic Dissection of Signalling From Phosphotyrosine Residue 1201 of the Oncogenic Neu Receptor Tyrosine Kinase

title: Genetic Dissection of the Oncogenic Neu^(YC) Signalling Pathway

contributor:
Jacobs, Roger
Biology

subject: R-Ras, Ras-independent, Ras-dependent, ErbB2, Neu, tyrosine kinase, breast cancer, ovarian cancers, MAPK, cells, genetic, Dorsophila, EGFR, YC GTPase, Ras-related

abstract:
 The ErbB2/Neu orphan receptor tyrosine kinase is amplified in 20-30% of breast and ovarian cancers and predicates poor patient prognosis. Five conserved tyrosine residues, autophosphorylated by Neu catalytic activity, "dock" adaptors and second messengers that activate discrete signalling pathways, most prominently the Ras/MAPK pathway, to regulate cell survival and proliferation.

 Genetic analysis using Drosophila provides an efficient means for identifying evolutionarily conserved signalling components. Neu and Drosophila EGFR overexpression directs Drosophila tissue development synonymously. Consistent with biochemical evidence, genetic analysis ofNeu signalling through individual pTyr revealed activating signals for 4(Yl144, YB; Y1201, YC; Y1226/7, YD; Y1253, YE) of the 5 sites. Strong Ras-dependent signalling was mediated through adaptors Grb-2 (YB) and SHC (YD). In contrast to biochemical evidence, a strong Ras component was not genetically detected for YC or YE.

 We have conducted two enhancer-suppressor screens to identify novel Ras and non-Ras requirements for YC signalling. For the first screen, a quantitative approach was designed to identify modification of an YC-specific wing notch phenotype. Thirty-two members of the Ras/MAPK signalling cassette were assessed. Sensitivity to Ras, Raf, MAPK and the Ras-related GTPase R-Ras was identified downstream ofYC. The second screen, a large-scale mutagenesis, took advantage of an YC-induced rough eye phenotype. From over 19 000 screened flies, 11 enhancers and 6 suppressors were isolated. One strong suppressor has been genetically mapped to the dual transcription factor and phosphatase eyes absent. Other promising Ras-dependent and Ras-independent modifiers await farther mapping. Results from both screens point to YC as a unique pTyr that uses both Ras-dependent and Ras-independent outputs.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Dense Core Formation Simulations in Turbulent Molecular Clouds with Large Scale Anisotropy

contributor:
Sills, A.
Wadsley, J.
Physics and Astronomy

subject: formation, clustered, molecular, Particle, turbulence, gravitational, anisotropy

abstract:
 In this thesis, we study star formation in clustered environment within molecular
clouds using Smooth Particle Hydrodynamics (SPH) simulations. Our
first approach was to use "sink particles" to replace the dense gas particles
where stars are forming. We implemented this type of particle in GASOLINE,
and ran a simulation with a similar set of parameters to Bate et al. (2003).
We found a good general agreement with this study. However, this work
raised increasing concerns about some of the approximations used to follow
the fragmentation process over many orders of magnitude in density. Our first
issue was with the polytropic equation of state used to simulate gas of high
density, that we believe would require some form of radiative transfer to be
reliable. We also had concerns about the sink particles themselves, potentially
overestimating the accretion rates.

 This guided our following work, where we choose to avoid both sinks and polytropic assumptions; allowing us to concentrate on the role of turbulence in forming prestellar cores. Supersonic turbulence is known to decay
rapidly even when considering magnetic fields and gravity. However these
studies are based on grid codes for periodic boxes. Our simulations are not
periodic, they have open boundaries. Therefore the gravitational collapse can
occur for the whole molecular cloud, not only for small portions of it. Hence
the picture we observe in our self-gravitating turbulent molecular clouds is
different. We found that under gravitational collapse turbulence is naturally
developed and maintained with properties in good agreement with the current
observational and theoretical picture.

 We also compared the cores we formed with observations. We looked at several observable properties of cores: density profiles, velocity dispersion and rotation of the cores, core-core velocity dispersion, core-envelope velocity
dispersion, velocity dispersion vs. core size relation and the core mass function. We found a good general agreement between our simulated and observed
cores, which indicates that extra physics like magnetic fields, outflows, proper
equation of state or radiative transfer would have only secondary effects at
this formation stages, or would tend to cancel each other.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: REGULATORY T CELLS AND OBSTETRIC COMPLICATION: PERINATAL DEPRESSION AND CARDIOVASCULAR HEALTH

contributor:
Steiner, Meir
Neuroscience

subject:
perinatal depression
regulatory T cells
cardiovascular

abstract: Regulatory T cells (TRegs) are stable markers of immune functioning, acting to suppress inflammation. TRegs are important during implantation and early pregnancy where they suppress immune-mediated rejection of the embryo. Given the role of TRegs in the maintenance of pregnancy, their depletion can be associated with obstetric complications. Through the completion of two studies, this thesis seeks to identify the role of TRegs in two forms of perinatal pathology: depression and arterial thickening. The first study examines whether decreased TReg levels during pregnancy are associated with an increase in depressive symptoms, and if this relationship is mediated by maternal stress. We predicted that the TReg-depression relationship would be unique to pregnancy, and not occur in the postpartum. In the second study we assessed if decreased TRegs were inversely correlated with carotid arterial thickness. TReg samples were obtained from women between 24 and 32 weeks gestation (N=16), and at 12 weeks postpartum (N=19). Depression was assessed using the Edinburgh Perinatal  Depression Scale (EPDS) and the Mongomery-Asberg Depression Rating Scale (MADRS) , and stress with the Perceived Stress Scale (PSS). TRegs were measured using flow cytometry. In the first study, we showed that lower TRegs were associated with increased levels of depression in pregnancy, and that this association was mediated by perceived stress. In the postpartum period, TRegs were not associated with changes in mood.  In the second study, we found no relationship between TRegs and carotid arterial thickness. Our results suggest that TReg changes in pregnancy may be associated with maternal mood in pregnancy, but not in the postpartum period. Despite the fact that we failed to find a correlation between TRegs and carotid arterial thickness during pregnancy, our limited sample size leads us to recommend that the presence of an inverse correlation between these two markers not be ruled out, but suggest that these links be further examined using a larger sample and more precise imaging. Together, these two studies may provide very early insights into the role of TRegs in perinatal mood disorders and cardiovascular health and highlight the need for further research.

abstract: Thesis

abstract: Master of Science (MSc)


title: Metal-Assisted Growth of III-V Nanowires By Molecular Beam Epitaxy

contributor:
LaPierre, Ray R.
Engineering Physics

subject: III-V nanowires (NWs), molecular beam epitaxy, (1 1 1)B, morphology, crystal structure, GaAs, V/III flux ratio, Ga Flux, Low and intermediate growth temperatures, material conservation model

abstract:
 The mechanisms operating during the metal-assisted growth of III-V nanowires (NWs) by molecular beam epitaxy on (1 1 l)B substrates were investigated through a series of experiments aimed at determining the influence of growth conditions on the morphology and crystal structure. Using GaAs as the principal material system for these studies, it is shown that a good control of these two characteristics can be achieved via a tight control of the temperature, V /III flux ratio, and Ga flux. Low and intermediate growth temperatures of 400°C and 500°C resulted in a strongly tapered morphology, with stacking faults occurring at an average rate of 0.1 nm^(-1). NWs with uniform diameter and the occurrence of crystal defects reduced by more than an order of magnitude were achieved at 600°C, a V /III flux ratio of 2.3, and a Ga impingement rate on the surface of 0.07 nm/s, and suggest the axial growth is group V limited. Increasing the flux ratio favored uniform sidewall growth, thus making the process suitable for the fabrication of core-shell structures. Further observation of steps on the sidewall surface of strongly tapered NWs suggests that radial growth of the shell proceeds in a layer-by-layer fashion, with the edge progressing in a step-flow mode toward the tip.

 From the experimental considerations, an analytical description of the growth is proposed, based on a simple material conservation model. Direct impingement of growth species on the particle, coupled to their diffusion from the sidewall and the substrate surface, are considered in the derivation of expressions for the time evolution of both axial and radial growths. Factors that take into account the nonunity probability of inclusion of group III adatoms in the axially growing crystal are introduced. Moreover, a step-mediated growth is included to describe the axial evolution of the shell.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Existence of Radially Symmetric Vortices in a Ferromagnetic Model of Superconductivity

contributor:
Alama, Stanley
Mathematics

subject: Analysis PDE Ferromagnetism Superconductivity

abstract:
We take a model for Ferromagnetic Superconductors based on a variational
energy functional, and search for radially symmetric minimizers. First we define
what it means for a solution to the Euler-Lagrange equations to be admissible,
before relating these admissible solutions to an appropriate function space. We
then use a variational approach to prove the existence of minimizers. Since it is
not clear at first whether or not the energy is bounded below, the direct method
of the calculus of variations does not apply. Instead, we first prove existence in
a case where the energy is bounded below, namely when the Zeeman coupling
constant g vanishes. We then use the implicit function theorem to prove the
existence of physically relevant minimizers for small values of g.

abstract: Thesis

abstract: Master of Science (MSc)


title: An experimental study of steam generator tube loading during a two-phase blowdown

contributor:
Weaver, David
Mechanical Engineering

subject: Transient two-phase blowdown

abstract:
This research studies the effects of a postulated Main Steam Line Break accident in a nuclear plant on the transient loading of steam generator tubes. The problem involves complex transient two-phase flow dynamics and fluid-structural loading processes. A better understanding of this phenomenon will permit the development of improved design tools to ensure steam generator safety.
This Thesis presents the results of an experimental laboratory study of the transient loading of a sectional model of steam generator tubes during a simulated two-phase blowdown. The research was carried out in a purpose designed and built experimental facility. The thermodynamic phenomena were investigated through dynamic pressures and temperatures. The transient tube loads were directly measured using dynamic load cells. The working fluid was R-134a and the tube bundle was a normal triangular array with a pitch ratio of 1.36.
Preliminary testing indicated parasitic loading on the instruments and remedial actions were taken to ensure measurement accuracy. The success of the instrumentation development methodologies was validated in a series of single- phase blowdowns. Two-phase blowdown experiments were then conducted with various levels of liquid and numbers of tube rows. The results provided hitherto unknown information relating the nature of the fluid-structure interaction and flow development during a two-phase transient blowdown across a tube bundle.
The pressure drop across the tube bundle established the thermal hydraulic fluid behaviour in the pressure vessel and controlled the upstream fluid discharge from the system. The flow through the bundle was choked for the majority of the transient. The transient tube loading was explained in terms of the associated fluid mechanics and the maximum load was compared with existing models obtained under steady flow conditions. An empirical model was developed that enables the prediction of the maximum tube loads once the pressure drop is known.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: The design of nuclear plant systems requires that public safety be ensured for the worst-case imaginable accident scenarios. This means that radioactive materials produced by nuclear fission must be safely contained. If the main steam pipe from a nuclear steam generator were to break, the water in the steam generator would rapidly boil off in what is called a blowdown. Such an event could produce significant loading on the heat exchanger tubes. Should the tubes rupture, radioactive materials may breach reactor containment. Thus, knowing the tube loading during this hypothetical scenario is an important input for safe design. The goal of this research is to improve our understanding of the effects of this postulated accident on the transient loading of the tubes. A laboratory study was carried out to simulate the blowdown. The experimental results provided valuable insights and guidance for the development of improved design tools.


title: Word Reading Skills of Beginning Non-Readers: Effects of Training With a Visible Orthography

title: Visible Orthography Training And Beginning Reading Skills

contributor:
Levy, B. A.
Psychology

subject: spelling patterns, english, oral segmentation, non-readers, rime families, rimes

abstract: The experiments presented here investigated the effects of manipulating the visibility of spelling patterns in English print, without concurrent oral segmentation, on the word identification skills of beginning non-readers. Visibility of the orthographic patterns was manipulated by presenting material organized into rime families (blocked) or with rime families distributed throughout training (unblocked), as well as through highlighting common rimes in the same colour of print. Experiment 1 demonstrated that while a program emphasizing the orthographic patterns in the English writing system (without concurrent phonological segmentation) led to rapid improvements in beginning non-readers' on line word identification, the benefits of such training did not persist beyond the training context. Experiments 2A and 2B investigated whether the failure to transfer word reading skills beyond the blocked training context was mitigated by training programs that required increased focus on the letter patterns (2A) and the letter-sound relations (2B). These manipulations did not influence performance; children continued to demonstrate poor transfer beyond the training context. Experiment 3 focused on determining the mechanisms underlying the poor transfer following blocked training. To evaluate performance, this final experiment used a novel measure comprising word identification as well as onset and rime identification. Training materials were blocked either by rimes or onsets. The question of interest was whether training on material that blocks by orthographic units allows children to identify the blocked units during training without actively decoding their letter-sound relations, thus decreasing the probability of forming connections between the graphemes and phonemes comprising them. Results indicated that this is the case when children were trained on material blocked by rimes, but not that blocked by onsets.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Advances in the adjoint variable method for time-domain electromagnetic simulations

contributor:
Bakr, Mohamed H.
Electrical and Computer Engineering

subject:
Adjoint variable method (AVM)
computational electromagnetics
finite-difference time-domain (FDTD)

abstract: This thesis covers recent advances in the adjoint variable method for the sensitivity estimations through time-domain electromagnetic simulations. It considers both frequency-independent and frequency-dependent response functions, and at the same time, provides a novel adjoint treatment for addressing dispersive sensitivity parameters in the material constitutive relation.  With this proposed adjoint technique, response sensitivities with respect to all N sensitivity parameters can be computed through at most one extra simulations regardless of the value of N.  This thesis also extends the existing adjoint technique to estimate all N^2 second-order sensitivity entries in the response Hessian matrix through N additional simulations. All adjoint sensitivity techniques presented in this thesis are numerically validated through various practical examples. Comparison shows that our produced adjoint results agree with those produced through central finite-difference approximations or through exact analytical approaches.

abstract: Dissertation

abstract: Doctor of Engineering (DEng)


title: SOLID‐STATE NMR OF HIGH TEMPERATURE FUEL CELL ELECTROLYTES

contributor:
Goward, Gillian
Chemistry and Chemical Biology

abstract: Current fuel cell operating temperatures have been unintentionally optimized for the exact conditions that poison the platinum electrode. Raising the operating temperature can eliminate poisoning. Nafion®, the current benchmark fuel cell electrolyte, operates optimally at 80oC due to its dependence on water for proton conduction.  Two approaches are described here to address this issue: modification of Nafion to remain hydrated and the synthesis of new materials that can operate at high temperatures. Casting the polymer with smaller thicknesses reduces the path length and allows water to diffuse throughout the whole polymer easily. When nanothin versions of the film were cast, water uptake was found to be significantly higher. However, the observed   proton conductivity decreased.  Solid-state NMR was used to determine if local dynamics were an issue in nanothin films or whether long-range transport was hindered.  For materials that operate via a Grotthuss mechanism, organic solid acids were studied due to their thermal and electrochemical stability and significant proton conductivity at high temperatures.  For this thesis three main organic solid acids were studied, including benzimidazolium- and imidazolium- methanesulfonate (BMSA and IMSA) and imidazolium trifluoromethanesulfonate (IFMS). Solid-state NMR was used to study their hydrogen-bonded structure to determine the dynamics in each of the solid acids. The local dynamics information was then compared with their macroscale proton conductivity.  To produce a suitable host for fuel cell applications, the solid acids were inserted into polymer supports to determine the best salt-host composite. Polymers supports that were investigated include Teflon, sulfonated polyetheretherketone (sPEEK) and sulfonated polysulfone (sPSU).  This thesis focuses on the use of solid-state NMR to probe these composites and to study their mobility on a localized scale to explain their macroscale proton conductivity.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Radiation Induced Bystander Responses In Vertebrates Given Low Doses Of In Vivo Radiation

title: Bystander Resposes In Vertebrates Given In Vivo Radiation

subject: cells, radiation, irradiations, in vivo, genetic, vertebrates, irradiated, dose dependant, clonogenic, sex-depedent, ITCM

abstract:
 The bystander response phenomenon shows that radiation induced changes in cells that have not been directly targeted, but are neighbors to or receive medium from directly hit cells. Our group has performed a range of single and serial, low dose irradiations (in vivo) on two strains of mice that have been documented to show genetic differences in their response to radiation. This thesis also explores the impact of environmental radiation contamination on female and male Mink frogs (Rana septentrionalis) sampled from contaminated and background (control) radiation sites. Bladder explants established from these vertebrates are incubated in culture medium, which is then used to measure apoptotic response (cell survival and calcium flux) in the keratinocyte reporter system.

 This study reveals that culture medium from acutely irradiated C57Bl6 mice, but not Balb/c mice, induces dose-dependant clonogenic death. The administration of a priming dose(s) to C57BL6, but not Balb/c mice, leads to stimulatory growth effects in reporters regardless of the time separation between the priming and challenge dose. Similarly, ITCM corresponding to male and female contaminated frogs results in a sexdependent decrease in reporter survival, but no reduction is induced from ITCM sampled from explants from female and male frogs from uncontaminated sites. When the ITCM is measured for its calcium inducing ability, results show abnormal calcium levels in both strains of mice only after the administration of a priming dose. However, chronic exposures to male and female frogs results in the production of ITCM that induces transient calcium flux in reporters. These results indicate that genetic predisposition in mice influences the type of bystander signal that is produced after exposure to low, acute doses of radiation. However, when mice are repeatedly exposed to radiation, the bystander signal is modified in a way that may be causing unregulated growth in reporter cells.

abstract: Thesis

abstract: Master of Science (MS)


title: Electrohydrodynamic Control of Convective Condensation Heat Transfer and Pressure Drop in a Horizontal Annular Channel

contributor:
Ching, Chan Y.
Cotton, James S.
Shoukri, Mamdouh
Mechanical Engineering

subject: voltage, electric field, electrohydrodynamic, condensation, pressure, annular, channel

abstract:
 The objective of this research is to investigate the effect of DC, AC and pulse wave
applied voltage on two-phase flow patterns, heat transfer and pressure drop during
tube side convective condensation of refrigerant HFC-134a in an annular channel. Experiments
were performed in a horizontal, single-pass, counter-current heat exchanger
with a rod electrode placed along the center of the tube. The electric field was applied
across the annular gap formed by the electrode connected to the high-voltage source
and the grounded surface of the inner tube of the heat exchanger. The electric field
between the two electrodes was established by applying a high voltage to the central
electrode. The high voltage was generated by amplifying the voltage output from a
function generator. The flow was visualized at the exit of the heat exchanger using
a high speed camera through a transparent quartz tube coated with an electrically
conductive film of tin oxide.

 The effect of a 8 kV DC applied voltage was investigated for mass flux in the range 45 kg/m^2s to 160 kg/m^2s and average quality of Xavg= 45%. The application of the 8 KV DC voltage increased heat transfer and pressure drop by factor 3 and 4.5 respectively at the lowest mass flux of 45 kg/m^2s. Increasing the mass flux decreased the effect of electrohydrodynamic forces on the two-phase flow heat transfer and pressure drop.

 The effect of different AC and pulse wave applied voltage parameters (e.g. waveform, amplitude, DC bias, AC frequency, pulse repetition rate and duty cycle) on heat transfer and pressure drop was investigated. Experiments were performed
with an applied sine and square waveform over a range of frequencies (2 Hz < f < 2 kHz), peak-to-peak voltages (2 kV < Vp-p < 12 kV) and DC bias voltage (-10 kV < VDc < 10 kV), and with an applied pulse voltage of amplitude 12 kV and duty cycle from 10% to 90%. These experiments were performed for a fixed mass flux of 100 kg/m^2s, inlet quality of 70%, and heat flux of 10 kW /m^2. For the same amplitude and DC bias, the pulse wave applied voltage provides a larger range of heat transfer and pressure drop control by varying the pulse repetition rate and duty cycle compared to the sine waveform.

 The effect of a step input voltage on two phase flow patterns, heat transfer and pressure drop was examined and analyzed for an initially stratified flow. The flow visualization images showed that the step input voltage caused the liquid to be extracted from the bottom liquid stratum toward the center electrode and then pushed to the bulk flow in the form of twisted liquid cones pointing outward from the central electrode. These transient flow patterns, which are characterized by high heat transfer compared to the DC case, diminish in steady state. The effect of the
amplitude of the step input voltage and the initial distance between the electrode and
liquid-vapour interface on the liquid extraction was investigated experimentally and
numerically. At sufficiently high voltages, the induced EHD forces at the liquid-vapour
interface overcame the gravitational forces and caused the liquid to be extracted
towards the high voltage electrode. The extraction time decreased with an increase
of the applied step voltage and/ or decrease of the initial distance between liquid
interface and the high voltage electrode. The numerical simulation results were, in
general, in agreement with the experimental results.

 The effect of pulse repetition rate of pulse applied voltage on two phase flow patterns, heat transfer and pressure drop can be divided into three regimes. At the low pulse repetition rate range, f < 10 Hz, the two-phase flow responded to the induced EHD forces, and liquid was extracted from the bottom stratum to the center electrode and then pushed back to the bulk flow in the form of twisted liquid cones. Increasing the pulse repetition rate in this range increased the repetition of the extraction cycle and therefore increased heat transfer and pressure drop. In the mid pulse repetition rate range, 10 Hz < f < 80 Hz, the extraction was not completed, which led to lower heat transfer compared to the lower pulse repetition rate range. In this range, the
two phase patterns were characterized by liquid-vapour interface oscillations between
the center electrode and the bottom stratum and liquid droplet oscillations which
increased the momentum transfer and therefore pressure drop. Increasing the pulse
repetition rate in this range decreased heat transfer and increased pressure drop. In
the high pulse repetition rate range, f > 80 Hz, increasing the pulse repetition rate
decreased both the interfacial and droplet oscillations and therefore decreased the
heat transfer and pressure drop till the two phase flow patterns resembled that for
an applied DC voltage. For the same pulse repetition rate, increasing the mass flux
decreased the effect of EHD forces on heat transfer and pressure drop. The heat
transfer enhancement ratio and pressure drop ratio increased with an increase of the
duty cycle for the same pulse repetition rate of the applied voltage.

 Different combinations of pulse repetition rate and duty cycle of applied pulse
wave voltage can be used to achieve different values of heat transfer and pressure drop.
This can be very beneficial for heat transfer control in industrial applications. An
advantage of such control is that it eliminates various measurements devices, control
and bypass valves, variable speed pumps, fans and control schemes used in current
technology for heat transfer and pressure drop control. The range of control of the
ratio of the heat transfer coefficient to the pressure drop is from 8.24 to 20.56 for mass flux of 50 kg/m^2s and it decreased with increasing mass flux untill it reached
1.63 to 3.81 at mass flux 150 kg/m^2s.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Chronic post-surgical pain after noncardiac surgery

contributor:
Devereaux, PJ
Health Research Methodology

abstract: Chronic post-surgical pain (CPSP) is a debilitating complication of surgery. Despite increasing attention in recent years, there is a paucity of data on the incidence of CPSP after noncardiac surgery and the risk factors that affect its development. The studies in this thesis inform current knowledge gaps in the literature. Chapter 2 describes the interim results of a large, international prospective cohort study on the incidence of chronic incisional pain, a type of CPSP specific to the incision site, and its associated risk factors. Chapter 3 describes the association between postoperative patient coping and expectations about recovery after traumatic tibial fracture repair and the development of CPSP and its interference on normal work. Chapter 4 outlines methodological issues with pain measurement in clinical trials and describes a protocol for a randomized controlled trial that compares electronic data collection to traditional data collection methods when investigating CPSP.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Globular Cluster System of NGC 5128

contributor:
Harris, William E.
Physics and Astronomy

subject: globular cluster, galaxy, NGC 5128, colour, spatial distributions, ages, metallicities, galactocentric, field star, planetary nebulae, mass, mass to light ratio, universe, star, planets, rotation, protogalaxies

abstract:
 The globular cluster system of a nearby giant elliptical galaxy, NGC 5128 is studied to place constraints on the formation history of the galaxy. In this thesis, we have identified 190 new globular clusters via radial velocity measurements, bringing the total known population of globular clusters to 605 within this galaxy. We have examined the colour and spatial distributions of the globular cluster system and find it is bimodal in colour, with both a red and blue globular cluster population. The blue population is more spatially extended than the red, and both populations fall off in number density with radius as a power-law. There is a clear lack of globular clusters along the isophotal minor axis of the galaxy beyond a galactocentric radius of 15' warranting further search. With this new dataset, we have measured the ages, metallicities, and formation timescales for 72 globular clusters. The spectroscopic metallicity distribution function is bimodal indicating there is a metal-rich and metal-poor globular cluster population that corresponds to the red and blue globular clusters, respectively. We find the majority of both metal-rich (56%) and metal-poor (92%) globular clusters are older than 8 Gyr, comparable to the Milky Way globular cluster system. We do find a smaller fraction, 18% of our sample, are metal-rich globular clusters with ages younger than 5 Gyr, while the remaining globular clusters have intermediate ages between 5 -8 Gyr. The formation times of these globular clusters, estimated by their alpha-to-iron abundance ratios, indicate they formed quickly, on a timescale similar to globular clusters in most spiral galaxies, but on slower timescales than those in some other giant elliptical galaxies. The kinematics of the full globular cluster system is analyzed, as well as for the metal-rich and metal-poor globular clusters separately, as a function of galactocentric radius. We find the metal-poor globular cluster system has a small rotation signature of 17±14 km s-1 around no clearly defined axis and its dynamics are dominated by dispersion. The metal-rich globular cluster system has a mild rotation of 41 ± 15 km s-1 about the galaxy's isophotal major axis, following the rotation of a representative field star population, the planetary nebulae. The motion of the metal-rich globular cluster system is also dominated by random motion. We estimate the mass of the galaxy to be (5.5 ± 1.9) x 1011 with a mass-to-light ratio of 15.35 M0 /L80 using the globular cluster
M0 population out to 20'. This estimate places NGC 5128 on a mass scale similar to other giant elliptical galaxies. The evidence collected suggests that NGC 5128 formed in a hierarchical scenario, gradually building up larger structure from smaller protogalaxies at early times in the history of the Universe. The group environment of NGC 5128 may have prolonged star formation within the galaxy as well, enabling a small spread in the old ages of globular clusters and also slowing the formation timescales compared to globular clusters in other giant elliptical galaxies. Results from this thesis also support more recent accretions in the history of NGC 5128, building up the more metal-rich and young globular clusters, which have a different rotation axis than the rest of the population.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Pulmonary Host Defence Against Heterologous Infectious and Non-Infectious Challenges

title: Host Defence Against Complex Challenges

contributor:
Stampfli, Martin R.
Medical Sciences

subject: Lung Disease, infection, tobacco, smoke, exposure, pulmonary neutrophilia, cell, virus, influenza, bacterial superinfection, pathology, MIP-2, pathogens, macrophages, cells, immune system, mediating, medical, health, risks

abstract: Lung disease is the leading threat to human health worldwide. In particular, two threats are responsible for the majority of the pulmonary disease burden: infection and tobacco smoke exposure. Efforts to combat these diseases have been hampered by gaps in our understanding of the complex interactions between environmental threats and the host's own immune defences. Indeed, much of the pulmonary disease burden should be ascribed not to direct smoke-, virus-or bacteria-induced damage, but to maladaptive host defence responses against these threats. This is an understudied topic. Efforts to redress this deficiency have been hampered by the lack of available animal models. Thus, the present studies developed and examined models of Heterologous pulmonary infection, in which hosts must defend against two different infections, and of tobacco smoke exposure. In the first study, a critical role for MIP-2 driven pulmonary neutrophilia was elucidated in the pathology associated with bacterial superinfection of influenza virus infection. This study further demonstrated that the timing and sequence in which pathogens were encountered played important roles in determining the outcome of disease, and that viral and bacterial infections have different but long-lived impacts on alveolar macrophages. In the second study, it was determined that cigarette smoke exposure impacts host defence without exhausting T-or B-cells. Collectively, these studies have advanced our understanding of complex lung pathologies, and suggest an important role for the innate immune system in mediating such diseases.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)