title: Assignment Calculus: A Pure Imperative Reasoning Language

contributor:
Zucker, Jeffery
Computer Science

subject: calculus, language, reasoning, imperative, procedure, composition

abstract:
 In this thesis, we undertake a study of imperative reasoning. Beginning with a philosophical analysis of the distinction between imperative and functional language features, we define a (pure) imperative language as one whose constructs are inherently referentially opaque. We then give a definition of a reasoning language by identifying desirable properties such a language should have.

 The rest of the thesis presents a new pure imperative reasoning language, Assignment Calculus AC. The main idea behind AC is that R. Montague's modal operators of intension and extension are useful tools for modeling procedures in programming languages. This line of thought builds on T. Janssen's demonstration that Montague's intensional logic is well suited to dealing with assignment statements, pointers, and other difficult features of imperative languages.

 AC consists of only four basic constructs, assignment 'X := t', sequence 't; u', procedure formation 'it' and procedure invocation '!t'. Three interpretations are given for AC: an operational semantics, a denotational semantics, and a term-rewriting system. The three are shown to be equivalent. Running examples are used to illustrate each of the interpretations.

 Five variants of AC are then studied. By removing restrictions from AC's syntactic and denotational definitions, we can incorporate L-values, lazy evaluation, state backtracking, and procedure composition into AC. By incorporating procedure composition, we show that AC becomes a self-contained Turing complete language in the same way as the untyped λ-calculus: by encoding numerals, Booleans, and control structures as AC terms. Finally we look at the combination of AC with a typed λ-calculus.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Resource Management in Solar Powered Wireless Mesh Networks

contributor:
Todd, Terence D.
Electrical and Computer Engineering

subject: resource, solar, powered, wireless, mesh, networks, connections, algorithm, node, network

abstract:
 Wireless mesh networks are now being used to deploy radio coverage in a large variety of outdoor applications. One of the major obstacles that these networks face is that of providing the nodes with electrical power and wired network connections. Solar powered mesh nodes are increasingly used to eliminate the need for these types of connections, making the nodes truly tether-less. In these types of networks however, the cost of the energy collection and storage components can be a significant fraction of the total node cost, which motivates a careful selection of these resources.

 This thesis focusses on key issues relating to the deployment and operation of solar powered wireless mesh networks. First, the problem of provisioning the mesh nodes with a suitable solar panel and battery configuration is considered. This is done by assuming a bandwidth usage profile and using historical solar insolation data for the desired deployment location. A resource provisioning algorithm is proposed based on the use of temporal shortest-path routing and taking into account the node energy-flow for the target deployment time period. A methodology is introduced which uses a genetic algorithm (GA) to incorporate energy-aware routing into the resource assignment procedure. Results show that the proposed resource provisioning algorithm can achieve large cost savings when compared to conventional provisioning methods.

 During post-deployment network operation, the actual bandwidth profile and solar insolation may be different than that for which the nodes were originally provisioned. To prevent node outage, the network must reduce its workload by flow controlling its input traffic. The problem of admitting network bandwidth flows in a fair manner is also studied. A bound is first formulated which achieves the best max/min fair flow control subject to eliminating node outage. The bound motivates a proposed causal flow control algorithm whose operation uses prediction based on access to on-line historical weather data. The results show that the proposed algorithm performs well when compared to the analytic bound that is derived for this problem.

 Finally, as user traffic evolves, the network resources need to be updated. This problem is considered using a minimum cost upgrade objective. A mixed integer linear programming (MILP) formulation is derived to obtain a lower bound on the network update cost. A genetic algorithm is used to determine practical cost-effective network resource upgrading. The results show that the proposed methodology can obtain significant cost savings.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: THE HIGH DENSITY LIPOPROTEIN AND ATHEROSCLEROSIS

title: THE DEVELOPMENT OF ATHEROSCLEROSIS AND CORONARY OCCLUSION IN THE MOUSE:  INVESTIGATING THE HIGH DENSITY LIPOPROTEIN SIGNALING PATHWAY AND THE IMPACT OF THE SCAVENGER RECEPTOR CLASS B TYPE 1

contributor:
Trigatti, Bernardo
Biochemistry

abstract:
Coronary artery disease results from atherosclerotic plaque formation. High-density lipoprotein (HDL) has been shown to be inversely associated with the risk of coronary artery disease. It not only reduces lipid accumulation in atherosclerotic plaques by mediating reverse cholesterol transport, but also exerts direct protection on vascular cells via the scavenger receptor class B, type 1 (SR-B1).
Increased macrophage apoptosis is commonly observed in advanced or unstable atherosclerotic plaques. In this thesis, the anti-apoptotic effect and the signaling pathway of HDL in macrophages were investigated. We showed that HDL protected macrophages from endoplasmic reticulum (ER) stress induced apoptosis in a SR-B1 adaptor protein PDZK1 and Akt1 dependent manner. Also, atherogenic mice with PDZK1 deficiency in bone marrow-derived cells exhibited increased atherosclerotic plaque sizes with enlarged necrotic cores, which is a feature of rupture-prone plaques. We also found that HDL decreased the proapoptotic Bcl-2 related protein Bim in ER stressed macrophages, and Bim-/- macrophages were resistant to tunicamycin-induced apoptosis. Our in vitro study suggests that Bim is likely to be the downstream factor in the HDL signaling pathway. Consistent with this, inactivation of Bim in vivo significantly reduced plaque area and necrotic core size in a mouse model with low circulating HDL.
We also characterized the SR-B1-/-/apoE-/-, a spontaneous coronary heart disease model, by treating them with the clinically used heart disease drug rosuvastatin, and found that rosuvastatin protected SR-B1-/-/apoE-/- mice against atherothrombosis and attenuated myocardial fibrosis and cardiomegaly. This protection may be attributed to the ability of rosuvastatin to reduce oxidized LDL and inhibit macrophage foam cell formation. The work in this thesis contributes to a more detailed understanding of the impacts of HDL and SR-B1 on atherosclerosis.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


contributor:
Brophy, Sarah
English and Cultural Studies

subject: Judith Butler, rhetoric, recitations, critical, language

abstract:
 "Recitations: The Critical Foundations of Judith Butler's Rhetoric" explores the
textures and patterns in the writing of Judith Butler. Notoriously difficult, Butler's
rhetoric has garnered much scholarly and journalistic literature, and yet, to date, there
remains no book-length study on this topic. At the same time, Butler scholars have
tended to theorize her style as "subversive." Such a defense readily connects with
Butler's general effort to contour and challenge the lines of social and cultural
intelligibility, lines that deem some identities, especially sexual and racial ones,
unacceptable. However, I argue that the framework of "subversion" ultimately
reduces some of the generative tensions central to Butler's ideas, which I draw out by
focusing on the ambiguity of "recitation."

 Drawing on cultural and literary theory, particularly at the intersections between poststructuralism, psychoanalysis, feminism, queer theory, and semiology, I reframe Butler's writing through the questions of inheritance, paradigms, and critical alliances. Focused on three major works, I identify and research the thought of her key sources, and so the dissertation doubles as a study of G.W.F. Hegel (Butler's Subjects of Desire (1987), Sigmund Freud and Michel Foucault (The Psychic Life of
Power (1987), and Emmanuel Levinas (Giving an Account of Oneself(2005).
Focusing on the ways that Butler re-articulates and revises the language of these
influential writers, I develop a theory of Butler's style of critique that seeks to move
discussions of her writing past the notions of "subversion" and "liberation." More
broadly, I interpret the ambivalent scenes of identification and disavowal that Butler's
writing stages to shed light on problems of modern critical subjectivity, marked by
the inheritance of intellectual, social, and cultural structures that may trouble us, but
that also form our identities and our relations to others.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Congruency Between Parents' Actual and Desired Participation in the Care of Their Hospitalized Child

contributor:
O'Mara, Linda
Nursing

subject: congruency, hospitalized, child, parents, nursing,

abstract:
 Parents' participation in the care of their hospitalized child is an integral part of pediatric nursing practice and is considered to be beneficial for children and parents. However, parents may not discuss their participation with nurses and instead base their activities on their perceptions of nurses' assumptions and expectations regarding parents' participation in care. Nurses may assume a gate keeping role regarding parents' participation, deciding what parents will do and then monitoring these activities. Nurses' heavy workloads may preclude the teaching necessary for parents to participate in certain aspects of care. As a result, parents' actual participation in care may be more or less than their desired level of participation. Measuring actual participation alone may thus give an incomplete picture of a family's situation.

 To date, no attempt has been made to measure the difference between parents' actual and desired participation in care. A cross-sectional, descriptive design was used to measure parents' actual level of participation in care and their desired level of participation in care, and to describe the congruency between them. Parents of children admitted to medical and surgical units in a tertiary care children's hospital (N = 191) completed two instruments measuring desired and actual participation in care as well as providing demographic data. Study results indicate a difference between parents' actual and desired participation, with the majority of parents expressing a desire to increase their participation. Parents' care activities included providing comfort, assisting with activities of daily living, assisting with mechanical care and advocating for the hospitalized child.
Recommendations are made for nursing practice at the bedside, for nursing administration and for future research. Measuring congruency between actual and desired levels of participation can contribute to our understanding of parents' experiences of their child's hospitalization and may provide a unique perspective on parental participation in care.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Effects of Cognitive Control Exertion on Feeling States and Performance of a Graded Exercise Test

contributor:
Bray, Steven R.
Kinesiology

subject:
cognitive control
feeling states
self-control

abstract: Exerting cognitive self-control leads to subsequent decrements in muscular and cardiovascular endurance performance. According to the Process Model of self-control, affective feeling states may account for later self-control impairments. Affective feeling states are sensitive to exercise and show a pronounced negative shift in valence at the ventilatory threshold (VT). The purpose of this study was to investigate feeling states in response to a challenging cognitive control task (stop-signal task; SST) followed by a graded exercise task to exhaustion (GXT). Recreationally active participants (N = 20; Mage = 20.25) completed two testing sessions separated by one week. Sessions were counterbalanced, with either a control (SST-C) or experimental (SST-E) task performed prior to each GXT. Feeling states were measured using the Feeling Scale (FS) and Felt Arousal Scale (FAS) throughout both tasks. Time to exhaustion on the GXT was significantly shorter following the SST-E than the SST-C (p < .05; d = .49).  Repeated measures MANOVA showed similar within-task changes in FS in both conditions, but no significant differences between conditions during the SST tasks; however, FAS scores were significantly higher during the SST-E compared to the SST-C (p < .01). There were no significant differences in feeling states prior to, or upon completion of, the GXTs.  However, FS was significantly less positive at iso-time corresponding to predicted VT in the SST-E condition (p < .05). Results show feeling states during exercise are altered by prior cognitive control exertion. Decreases in positive valence in concert with increased activation may prime a negative shift in affect as exercise becomes more strenuous and thereby reduce self-control (exercise tolerance), as predicted by the Process Model. Alternatively, shifts in affect may reflect responses to physiological manifestations of fatigue that carry over from cognitive to physical tasks and become salient at moderate exercise intensities.

abstract: Thesis

abstract: Master of Science (MSc)


title: Magnetoresistance and Fermi Surface of Copper Single Crystals Containing Dislocations

contributor:
Niewczas, Marek
Materials Science and Engineering

subject: magnetoresistance, Fermi, surface, copper, single, crystals, dislocations, field

abstract:
 The galvanomagnetic properties and shape of the Fermi surface of copper single crystals containing different density of dislocations have been studied experimentally and theoretically through magnetoresistivity measurement and using effective medium theory respectively.

 In experiments, two crystallographic orientations of copper single crystal samples with tensile axis parallel to < 100 > and < 541 > have been plastically strained to various stress levels to introduce different density Nd of dislocations. The experimental data of angle and field-dependent magnetoresistivity measured at temperature T = 2K and in the magnetic filed up to 9 Tesla show that dislocations influence substantially the galvanomagnetic properties of copper crystal samples in the open, extended and closed orbit crystallographic orientations. The results reveal that the pure samples with resistivity ratio RR equal to or larger than 151 show quadratic dependence of transverse magnetoresistivity as a function of the magnetic field in the open-orbit orientation, which changes to linear variation of magnetoresistivity with magnetic fields in highly deformed samples with RR smaller than 138. A quadratic dependence of transverse magnetoresistivity as a function of the magnetic field is significantly suppressed as the density of dislocations increases. The magnetoresistivity decrease with the increase of the density of dislocations was also observed in the closed-orbit crystallographic orientation. Such effect is independent upon the type of dislocations introduced to the crystal lattice.

 Measurements of the de Hass-van Alphen effect in plastically deformed copper single crystals have been carried out with torque magnetometer and AC susceptibility options of Quantum Design PPMS-9 system. The oscillation frequencies for the extremal orbits normal to the principal crystallographic directions are obtained through Fourier transform of torque versus inversed field characteristics. By comparing these frequencies with the analogous frequencies obtained for undeformed copper crystals, the changes in the cross-sectional area of the Fermi surface corresponding to the extremal orbits are obtained and the shape of the dislocation-distorted Fermi surface is postulated based on measurements performed.

 The effective-medium approximation and Green's function method are applied to model the magnetoresistivity data and to gain insight into the fundamental material properties responsible for the observed magnetoresistivity behavior. The effective magnetoresistivity calculated using a self-consistent method shows a good agreement with the experimental results.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Assessment of the McMaster KN Accelerator for Nuclear Resonance Absorption and Fluorescence Experiments with 28Si Nucleus Induced by 27Al(p,γ)^28Si Capture Reaction

contributor:
Chettle, David R.
Medical Physics

subject: accelerator, nuclear, resonance, absorption, fluorescence, reaction, capture

abstract:
 This thesis represents a detailed assessment of the McMaster KN Accelerator site for the performance of a nuclear resonance absorption and fluorescence phenomenon in the 28Si nucleus. The main focus of this work is the 27Al(p, γ)^28 Si reaction, although other nuclear reactions are explored, such as: 27Al(p, p'γ)^27Al and 27Al(p, αγ)^24Mg. The gamma yield experiments from all these reactions suggest a repeatable and steady results, as well as very good agreement with the present literature. This is seen in chapter 2. Chapter 3 represents concrete nuclear resonance experiments with a direct ground state transition of the 12.33 MeV gamma energy from the 27Al(p, γ)^28Si reaction. These experiments are reproducible and repeatable with either HPGe or NaI(T1) (NaI elsewhere in text) detectors. Also, they are in close agreement with the literature.

 However, the main part of this work is described in chapter 4, where the first excited level of Si at 1.78 MeV is studied thoroughly. This is a pilot work that has never been attempted before. A thorough empirical approach is undertaken and described in section 4.1. This approach describes rationale for attempting nuclear resonance experiments with the first excited state of Si. The calculations suggest very close agreement between 12.33 MeV and 1.78 MeV experiments. Based on that, 7 different experimental sets, with several subsets ( within some of the sets) are performed. Very interesting results are obtained. However, so far, it cannot be concluded whether NRA/NRF experiments can be performed using the first excited state of Si. Most likely, hight current proton accelerators should be used and the experiments with 1.78 MeV lines should be repeated. These accelerators are described in chapter 5 and have the proton current output close to 1000 times higher than the McMaster KN accelerator. At the end, the dosimetry measurements suggest a negligible radiation dose from KN accelerator, as well as from these powerful accelerators.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Antecedents and Consequences of Collectivistic Group Norms

contributor:
Tasa, Kevin
Business Administration

subject: antecedents, consequences, group, norms, collective, team

abstract:
 Collectivism refers to a tendency to value group membership and collective responsibility. Much of what we know about how collectivism influences team effectiveness is drawn from research that has assumed collectivism to be determined by either cultural contexts (e.g., Hofstede, 1980), or individual differences (e.g., Triandis, Leung, Villareal, & Clack, 1985). Based largely in social psychology, another perspective is emerging in which collectivism is viewed as a group norm within a team. The issue of collectivistic group norms
within teams has yet to be examined in relation to team effectiveness outcomes, and may help to explain phenomena that have yet to be fully explained by cultural contexts or individual differences. In a longitudinal study of 60 self-managing teams performing a human resources management simulation, collectivistic group norms was positively associated with collective efficacy and team performance after controlling for the individual difference measure of psychological collectivism. Although psychological collectivism was positively associated with
collectivistic group norms, only the two psychological collectivism sub-dimensions of concern and norm acceptance were positively associated with collectivistic group norms while no associations were found between collectivistic group norms and the remaining three sub-dimensions of preference, reliance, and goal priority. Collective efficacy fully mediated the association between collectivistic group norms and team performance. Collectivistic group norm sharedness moderated the associations between collectivistic group norms and collective efficacy, and collectivistic group norms and team performance. This study is among the first to introduce collectivistic group norms to the organizational behaviour literature and to use collectivistic group norm sharedness to account for unique variance in collective efficacy and team performance.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Bundle Construction of Einstein Manifolds

contributor:
Wang, M. Y.
Mathematics

subject: bundle, construction, Einstein, manifolds, geometric, properties, dimensions

abstract:
 The aim of this thesis is to construct some smooth Einstein manifolds with nonzero Einstein constant, and then to investigate their topological and geometric properties.

 In the negative case, we are able to construct conformally compact Einstein metrics on
1. products of an arbitrary closed Einstein manifold and a certain even-dimensional ball bundle over products of Hodge Kähler-Einstein manifolds,
2. certain solid torus bundles over a single Fano Kähler-Einstein manifold. We compute the associated conformal invariants, i.e., the renormalized volume in even dimensions and the conformal anomaly in odd dimensions. As by-products, we obtain many Riemannian manifolds with vanishing Q-curvature.

 In the positive case, we are able to construct complete Einstein metrics on certain 3-sphere bundles over a Fano Kähler-Einstein manifold. We classify the homeomorphism and diffeomorphism types of the total spaces when the base manifold is the complex projective plane.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Women and the Soul-Body Dichotomy in Jacobean Drama

contributor:
Ostovich, Helen
English

subject: women, soul-body, dichotomy, Jacobean, drama, gender

abstract: Through examining various stage representations of women, this dissertation investigates both the limitations and possibilities that seventeenth-century conceptualizations of the soul-body relationship posed for female subject-positions. The gender-coded soul-body dichotomy lies at the root of many negative and disempowering depictions of women. And yet, this in many ways oppressive construct, I argue, could also function as an effective tool for radically redefining gender expectations. Women and the Soul-Body Dichotomy demonstrates how a critical awareness of a text's engagement with theories of the spirit-matter divide can suggest new readings of its representations of women - readings available to seventeenth-century audiences that we should not overlook. More specifically, I explore dramatic disruptions of the soul-body hierarchy, and the usual values attached to each "side," that significantly challenge the patriarchal subordination of women. While the recent emphasis on the body in early modern studies has proven immensely productive, this focus tends to eclipse seventeenth-century concepts of the soul and the soul-body dynamic. I insist here that not only developing ideas about the body, but ideas about soul and body together are what crucially shaped gender ideology and cultural perceptions of women.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Novel Applications of Machine Learning in Pipeline Inspection and Neuroscience

contributor:
Reilly, James P.
Hasey, Gary M.
Electrical and Computer Engineering

subject: novel, applications, machine, learning, pipeline, neuroscience

abstract:
 In this thesis we develop and evaluate automated "expert systems" for two applications: (i) gas/oil pipeline inspection using magnetic flux leakage information, (ii) treatment efficacy prediction and medical diagnosis using electroencephalograph (EEG) and clinical information. Both applications share the same methodology and procedure as they employ machine learning methods which learn their decision models using the training data (or past examples
in real life/environment).

 The magnetic flux leakage (MFL) technique is commonly used for nondestructive testing (NDT) of oil and gas pipelines which are mostly buried
underground. This testing involves the detection of metal defects and anomalies in the pipe wall, and the evaluation of the severity of these defects. The difficulty with the MFL method is the extent and complexity of the analysis of the MFL images. In this thesis we show how modern machine learning techniques can be used to considerable advantage in this respect.

 The problem of identifying in advance the most effective treatment agent for various psychiatric conditions remains an elusive goal. To address this challenge, an automated medical expert system is designed and then evaluated. The system is capable of predicting the treatment response for each individual patient at the outset of a therapy (i.e., using pre-treatment information) thus improving therapeutic efficiency and reducing personal and economic costs. Our experiments are focused on treatment planning and diagnosis of mood disorders and psychiatric illnesses. Through different experiments, we have
shown that it is possible to predict treatment efficacy of a 'selective serotonin reuptake inhibitor' (SSRI) antidepressant and 'repetitive transcranial magnetic stimulation' (rTMS) therapies for patients with treatment-resistant major depressive disorder (MDD) or major depression. The predictions are based on pre-treatment quantitative EEG measurements. Also, prediction of post-treatment schizophrenia symptomatic scores, using pre-treatment EEG data, showed significant performance in patients treated with the drug clozapine.
Clozapine is an antipsychotic medication of superior effectiveness in treating Schizophrenia but has several potentially severe side effects.

 Medical diagnosis is the second problem we consider in the neuroscience aspects of this thesis. In this research, an automated digital medical diagnosis methodology is developed to estimate/detect the type of a disease or illness that a patient is suffering. This intelligent diagnostic system can assist the
physician/clinician by offering a second opinion on diagnosis. Several complex psychiatric illnesses may have many common symptoms and accurate diagnosis can, at times, be very difficult. Efficient diagnosis helps by avoiding prescription of wrong therapy /treatment to a patient. In our limited experiments, EEG data is used to make a diagnosis for distinguishing between various psychiatric illnesses including MDD, schizophrenia, and the depressed phase of bipolar affective disorder (BAD).

 In all problems considered in this thesis, specifically the neuroscience problem, a large number of candidate features are extracted from measurement data but most candidate features are found to be irrelevant and have little or no discriminative power. Finding a few most discriminating features that guarantee
numerical efficiency and obtain a smooth and generalizable decision function, is a major challenge in this research. In this thesis, feature selection methods based on mutual information or Kullback-Leibler (KL) distance is employed to find the most statistically relevant features. For the multi-class diagnosis problem, to improve performance, a feature selection procedure denoted as feature combination feature selection is used which first finds discriminating features in all binary classification combinations, and then combines them into a larger feature subset to make a final multi-class decision. The two-dimensional (2D)
representation of the feature data is also found to be useful for clustering analysis. The overall method was evaluated using a nested cross-validation procedure for which over 80% average prediction performance is obtained in all experiments. The results indicate that machine learning methods hold considerable promise in solving the challenging problems encountered in the two applications of concern.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Essays on Empirical Dynamic Stochastic General Equilibrium Models

contributor:
Johri, Alok
Letendre, Marc-André
Scarth, William
Chan, Luke
Economics

subject: empirical, stochastic, equilibrium, models, dynamic, corporate

abstract: The overall goal of this thesis is to provide a deeper understanding of the role of dynamic stochastic general equilibrium (DSGE) models as foundations upon which empirical work is conducted. This is a very broad topic with a large existing literature. For this purpose, my dissertation focuses on applying the tools and rich structure of DSGE models to answer questions that have hitherto been studied only by using a reduced-form characterization. I have chosen to look at two specific macroeconomic questions of interest: the economic consequences of oil price shocks in Canada and the role of intangible capital (IC) in explaining cyclical dynamics of S&P500 earnings. Chapter 2 look at the economic consequences of oil price shocks in a structural vector autoregressions (VAR) framework. Chapter 3 builds on this by developing an open economy DSGE model to investigate the impact of oil price shocks on the aggregate Canadian economy and to quantify the relative contribution of U.S. and Canadian monetary policy in transmitting oil price shocks. Chapter 4 studies another interesting macroeconomic phenomenon: the excess volatility of aggregate profits. We embed intangible capital into an otherwise standard real business cycle (RBC) model to examine the role of intangible capital in driving cyclical dynamics of S&P500 earnings. A common feature of my papers is the application of Bayesian time series techniques to macroeconomic data to pursue new insights on "the impact of oil price shocks on economic activities", "the role of monetary policy in transmitting oil price shocks" in new open economic macroeconomics (NOEM) literature and "intangible capital and corporate earnings" in U.S. business cycle literature.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A Geographical Study of Land Use in South Dumfries Township

contributor:
Thompson, H. R.
Geography

subject:
South Dumfries Township
land use
agriculture
environment

abstract: This thesis was submitted in partial fulfillment of the requirements for the degree Bachelor of Arts.

abstract: Man, in earning a living, seeks to establish a satisfactory working relationship with the natural environment through the use of land in some manner. Adopting this geographical thesis, the following study is an attempt to examine and explain the relationship by describing and accounting for the nature, distribution, and areal differences of land use in South Dumfries Township. Information for the text was obtained through observation and interviews while in the field. This was supplemented by library research and map work. Statistical data were obtained from the Dominion Census Reports, planimetric measurements,and township assessment figures. The subject matter has been divided into three chapters, each of which has been subdivided into sections. The physical setting of the township is discussed in Chapter I. Chapter II concerns agricultural land use in the township, whereas, Chapter III is given to a discussion of the various non-agricultural land uses. The final section of the text contains a summary of the work and a synthesis of the factors which have affected man's relationship with the natural environment provided by the Township of South Dumfries.

abstract: Thesis

abstract: Bachelor of Arts (BA)


title: THREE ESSAYS ON FINANCIAL MARKETS

contributor:
Charupat, Narat
Qiu, Jiaping
Finance

abstract:
This thesis includes three essays that examine the effects of important events on the financial markets.
The first two essays study the market impact of a very successful financial innovation – the SPDR Gold Trust exchange-traded fund (GLD).  I find that after the introduction of GLD, the liquidity of gold company stocks declined, and their adverse-selection risk increased.  Over the two-month period after GLD's introduction, the stocks' relative effective bid-ask spreads increased by over 15%, while their adverse-selection cost, as measured by the price impact of trades, went up by more than 30%.  Gold stocks also experienced significant negative abnormal returns (-12% on average) in the month after GLD started trading.  My findings suggest that GLD attracted traders, especially uninformed traders, away from gold company stocks.  My results show that existing securities can be seriously adversely affected when a new security enters the market.
The third essay studies the effect of unionization on unsecured corporate creditors by testing the price reaction of publicly-traded bonds to union certification elections. I and my co-authors gather data on union elections covering several decades and employ a regression discontinuity design to identify the effect of worker unionization on bondholders’ wealth. We find that closely-won union elections lead to a 200 (500) basis points greater decline in bond cumulative abnormal returns than closely-lost elections during the 3-month (12-month) post-election window. However, unionization does not lead to poorer firm performance or higher default risk. Critically, the results show that unionization is associated with longer proceedings in bankruptcy court, with more bankruptcy emergences and subsequent refilings, and with higher fees and expenses paid to lawyers and financial experts in court. All of the costs diminish corporate asset values, aggravating bondholders’ losses.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: Connected Vehicles Using Visible Light Communications and Dedicated Short-Range Communications

contributor:
Hranilovic, Steve
Electrical and Computer Engineering

subject:
Connected Vehicles
Camera Communications
DSRC
VLC
Dedicated Short Range Communications
Visible light Communications

abstract:
Connected Vehicle (CV) is a motorized vehicle that can communicate with its interior and exterior surroundings. Connected Vehicle focuses on localized vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) to support safety, mobility and environmental applications. In this work, a simulation framework is presented. The framework quantifies Connected Vehicle performance in a forward collision warning situation. The simulation framework evaluates the performance using a vehicular traffic simulator with data from an intersection in Toronto, ON Canada. Various communication methodologies are evaluated at different Connected Vehicle market penetration rates. While DSRC is an interference limited communication methodology and visible light communications is a line-of-sight communication, the combination of both is evaluated to quantify the vehicular network safety performance in terms of time to collision. The performance of DSRC in a vehicular network is quantified in an interference dominant environment and the VLC performance in the vehicular network is evaluated at different weather conditions. In a specific vehicular traffic situation namely for- ward collision warning, this research quantified the VLC performance improvement in vehicular network safety to be 11% in addition to DSRC.This work concludes with the simulation and prototyping of camera communications for vehicular applications. Specifically this thesis presents multiple input / multiple output camera communications link utilizing a luminary array as a transmitter and two orthogonal low cost rolling shutter cameras as a receiver with the purpose of increasing the achievable data rate with one camera.
This work has demonstrated that there is at most a doubling in the data rate using two cameras over a single one. This data rate increase is achievable using a specific camera setup namely orthogonal cameras.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Adhesion of Silicone Hydrogel to Silicate Substrates

contributor:
Pelton, Robert Jr
Chemical Engineering

subject:
Adhesion
Silicone Hydrogel
Silicate Substrates
Silane
Surface Modification
Peel Test

abstract: The challenge of demolding during the cast molding process of silicone hydrogel contact lenses can be addressed with the application of hydrophobic coatings on the surface of lens mold. In particular, the adhesion between silicone hydrogel and silicate substrates was minimized by applying silane modification on the surface of silicate substrates. Peel tests were conducted to measure the adhesive strengths between silicone hydrogel and surface modified glass substrates. Water contact angle measurement and X-ray photoelectron spectroscopy (XPS) were utilized to characterize the surface properties of silane treated glass substrates.Silicone hydrogel was obtained by curing macromer mixture under UV for 6 minutes, with UV intensity of 95.0 mW/cm2. The obtained silicone hydrogel had a modulus of 0.87±0.09 MPa, within the same range of commercial contact lenses. And the hydrogel with a UV curing time of 6 minutes was unable to be peeled off from clean glass substrates. The effects of silane type and concentration on coating effectiveness were investigated and the most effective types of silane were found to be triethoxyphenylsilane (TEPhS) and octyltriethoxysilane (OTES), with an optimal concentration of 5 wt%. The peel strength between silicone hydrogel and silicate substrates was reduced to below 15.5 N/m with the application of TEPhS and OTES coatings. However, these silane coatings were not durable enough. Silane coupling agents need to be reapplied before each curing process of silicone hydrogel.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: BEHAVIOURAL FOUNDATIONS OF FEATURE MODELING

contributor:
Maibaum, Tom
Diskin, Zinovy
Computing and Software

subject:
Software Product Lines
Feature Modeling
Basic Feature Models
Cardinality-Based Feature Models
Modal Logic
Multiset Theory
Formal Languages
Faithful Semantics

abstract: Software product line engineering is a common method for designing complex software systems. Feature modeling is the most common approach to specify product lines. A feature model is a feature diagram (a special tree of features) plus some crosscutting constraints. Feature modeling languages are grouped into basic and cardinality-based models. The common understanding of the semantics of feature models is a Boolean semantics. We discuss a major deficiency of this semantics and fix it by applying, in turn, modal logic, the theory of multisets, and formal language theory. In order to adequately represent the semantics of basic models, we propose a Kripke semantics and show that basic feature modeling needs a modal rather than Boolean logic. We propose two multiset based theories for cardinality-based feature diagrams, called flat and hierarchical semantics. We show that the hierarchical semantics of a given cardinality-based diagram captures all information in the diagram. We also charac- terize sets of multisets, which can provide a hierarchical semantics of some diagrams. We provide three different reduction processes going from a cardinality-based diagram to an appropriate regular expression. As for crosscutting constraints, we propose a formal language interpretation of them. We also characterize some existing analysis operations over feature models in terms of operations on the corresponding languages and discuss the relevant decidability problems.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: PRESSURE RELATED STANDARDS AND PERFORMANCE OF WATER DISTRIBUTION SYSTEMS

contributor:
Guo, Yiping
Karney, Bryan
Civil Engineering

subject:
Pressure standards
Water distribution systems
Energy use
Leakage
Pipe breaks
Hydraulic transient

abstract: The standard design approach of water distribution systems requires that pressure at any point in the system is maintained within a range whereby the maximum pressure is not exceeded so that the likelihood of a pipe burst is reduced and the minimum pressure is always maintained or exceeded to ensure adequate flows for satisfying expected demands. High pressure systems tend to cause more frequent pipe breaks and an increase in energy use and leakage. Low pressure systems cause consumer complaints, make the system more susceptible to negative pressures, and possibly to the ingress of contaminants during transient events. The overall goal of establishing pressure standards is to balance these opposing tendencies to achieve a safe, reliable, and economic operation of the system. Yet, there are no universally acceptable or established rules or guidelines for establishing a pressure standard for water distribution system design, and few studies have considered whether the traditional standards are still applicable in modern systems. This study has made a critical appraisal on what pressure standards mean, where they are violated, and where they need revision to achieve a comprehensive picture about what the pressure standards really mean. The research also highlights the inter-related issues associated with pressure criteria. Assessment of the relationships governing water pressure, leakage, energy use and economics is realized via the analytical investigation of single pipes and the simulation of representative networks using the steady state analysis software EPANET 2. The role of minimum pressure standards, storage, pumping strategy, and resource prices on the energy and water loss of systems is analysed and assessed. In anticipation that pressure contributes to pipe break rates, a probabilistic approach considering uncertain water demand and pipe’s roughness modeled with a Monte Carlo simulation (MCS) algorithm is presented. This study also explores how the minimum pressure standards affect transient pressures and reviews how destructive transient pressures may be controlled to limit reduced pressure surges within acceptable limits even when the minimum steady state pressure is relatively low. In order to place the research in practical context, this study develops a surge limit control algorithm for the design of a portable device for limiting the down-surge pressures by creating a pressure control boundary in a pipe system during hydrant operations. This boundary is established using the portable control device to safely operate a hydrant in a water distribution system. This study also highlights the notion that high level of pressure standards may lead to a troublesome squandering of water and energy and may disrupt the performance of water distribution systems. Given the too often degraded nature of water supply infrastructures, the on-going challenges of urban growth, and the increased stress on natural resources, the significant benefits of better controlling water pressure are not only welcome but urgently needed.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Social services for newcomers to Canada: A systematic review of the evidence on provision, management, and outcomes of available services

contributor:
Wakefield, Patricia
Global Health

subject:
social services
newcomers
Canada
immigrant
refugee
settlement
integration

abstract:
Background: Canada brings in more than 200 000 newcomers annually, many of who require the use of social services to aid in their integration process. In 2011, the federal government made a 12% cut to the budget allocated for newcomer services, resulting in the closure of many services and decreased overall service capacity. The purpose of this study is to understand how social services for newcomers are provided, managed, evaluated, and funded.
Methodology: Seven electronic databases (CINAHL, Global Health, Medline, Ovid Healthstar, PAIS, PsycINFO, and Sociological Abstracts) were searched using search terms related to newcomers, social services, and Canada (as a jurisdictional limit). Thematic Synthesis methodology was used to code textual data, and extract descriptive themes to further analyze to determine analytical themes.
Results: A total of 20 studies were selected for the systematic review (19 through database search, 1 through a search of references). From these, 7 descriptive themes were found and analyzed to determine 2 analytical themes. Findings exhibit unique interactions between different levels of service delivery for newcomers, but also demonstrate scarcity of data and research dedicated to the topic.
Conclusion: Due to significant changes in the governance structures that determine what services are provided and how they are funded, it is essential that future research focus on these changes and their impact on newcomer integration. Additionally, a deeper understanding of the relationships between and within different levels of service delivery is required.

abstract: Thesis

abstract: Master of Science (MSc)


title: Controlled Diffusion Solidification: Process Mechanism and Parameter Study

contributor:
Shankar, Sumanth
Mechanical Engineering

subject:
casting
thixoforming
rheocasting
alloy
controlled diffusion solidification

abstract:
In the last forty years, most of researches in casting fields especially in semi-solid metal state were dedicated to find new ways to enable near net shaped casting of Al alloys to improve the product properties and decreases the product cost. The thixoforming and rheocasting processes are presented as a ways by which the microstructure of the alloys can be changed to non-dendritic microstructure leading to improve the mechanical properties by mitigating the defect associated with the dendritic microstructure. Unfortunately, these processes have proved to be capital cost prohibitive and complicated for commercial production. Further, near net shaped casting of Al wrought alloys along with the superior properties and performance of these alloys have been a challenge for conventional casting routes due to the main disadvantage of hot tearing or hot cracking during solidification, which renders the cast component ineffective. To overcome the disadvantages of thixoforming and rheocasting processes, Controlled diffusion solidification (CDS) process was innovated to enable casting aluminum alloys with a non-dendritic morphology of the primary Al phase in the resultant cast microstructure and thus alleviating the problem of hot tearing and obtaining a cost effective product with improved mechanical properties. The CDS is a simple process involving mixing of two precursor alloys of different thermal masses  (temperature and solute) and subsequently cast the resultant mixture of the desired solute composition and temperature as a near net shaped cast product. The process lends itself to easy commercialization with a marginal capital cost required for set up such as the addition of an extra holding furnace. Further, the CDS process would prove itself to be unique in its ability to cast Al based wrought alloys into near net shaped components without additional processes and cost.

The CDS process has been proven to yield a cast product with a non-dendritic Al phase morphology and this dissertation presents the in-depth details and analysis of the various events occurring during the process to obtain a successful cast part. The process involves various inter-related events such as mixing, re-distribution of thermal field, redistribution of solute field, three types of nucleation events and growth of these different nuclei. Further the dissertation aims to present a study of the critical parameters such as temperatures of the two pre-cursor alloys, initial mass ratio of these alloys and the rate of mixing them on the effectiveness of the CDS process.

The results from this study shows that mixing two precursor alloys to form the final desired alloy presents a natural environment for copious nucleation events aided by distribution of these nuclei by forced convection followed by the formation of unique cells in the resultant mixture (micro-scale) with significant thermal and solute gradients. The solidification in the CDS process is unique and different from conventional casting process in that initial growth of the nuclei takes place with the solute diffusing towards and temperature diffusing away from the solid/liquid interface which presents a favorable environment for a stable unperturbed growth of the solid/liquid interface resulting in a non-dendritic morphology of the primary AI phase.

The proposed events in the CDS process has been verified with a few Al based wrought
alloys and organic alloy systems.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A geographical study of Wainfleet township

contributor:
Wood, H. A.
Geography

subject:
Wainfleet
township
geographical study
physical geography

abstract:
A Geography 4C6 research paper
Thesis
Bachelor of Arts (BA)


title: Public Policy and Community: The Impact of Regional Government on Pelham, Ontario

subject: public, policy, community, regional, government, Pelham, Ontario, political

abstract:
 The focus of this study is the impact of Ontario's regional government schemes on the small town of Pelham where the writer lived as a participant-observer for two years. The argument is made that, while some benefits have been achieved in the provision of certain services, regional government is more of a failure than a success. Pelhamites have found that the new local and regional governments are quite antithetical to what they knew and valued in local politics. Consequently, as a group, these citizens are more antagonistic to their government than they remembered having been prior to the structural reform. This antagonism is felt more intensely among the traditionalists living in the rural areas than among the newly arrived village commuters. The departure from the past is symbolized by planning, a policy framework significantly different from the political style of the old councils. The conflict between local citizens and the new organizations is best illustrated by two public decisions, the implementation of land planning and the closure of schools. These two policies are examined in detail to point out the difficulties that have arisen because of provincial efforts to reform local government institutions without taking into account community values. It is apparent that Pelhamites are not satisfied that the new governments are concerned about their town nor are they confident of their own ability to influence major policy outcomes. The most damaging impact is that it is widely
accepted in the town that provincial authorities have not created new communities as promised but have destroyed what community had existed for the people of Pelham.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Metabolic and Structural Response of Human Skeletal Muscle to Acute Exercise and Nutritional Manipulation

contributor:
Gibala, Martin J.
Kinesiology

subject: metabolic, structural, human, skeletal, muscle, exercise, nutritional

abstract: The work in this thesis describes the metabolic and structural response of human skeletal muscle to acute exercise and nutritional manipulation. Over a series of three studies, healthy young men performed acute bouts of either endurance or resistance exercise, and a range of invasive and non-invasive techniques were applied to examine the muscle adaptive response during exercise and recovery. Study 1 investigated the hypothesis that co-ingestion of protein with carbohydrate during exercise would improve oxidative energy metabolism and attenuate ultrastructural disruption during prolonged 90 min of cycling at ~70% VO2peak. While protein ingestion increased blood amino acids, there was no difference between treatments in glycogen degradation or the content of TCA cycle intermediates during exercise, or the blood concentration of plasma creatine kinase (CK) after 24 h of recovery. Given the limitations associated with traditional indirect markers of muscle injury, study 2 examined the potential for a non-invasive imaging technique, diffusion tensor magnetic resonance imaging (DT-MRI), to detect exercise-induced changes in skeletal muscle structure. Subjects performed 300 eccentric actions of the leg extensors, a protocol previously shown to induce histological evidence of muscle disruption. DT-MRI revealed changes consistent with muscle disorganization 24 h post-exercise compared to baseline, including decreased fractional anisotropy (FA) and increased tensor eigenvalue λ3. The exercise protocol also induced changes in traditional direct and indirect markers of muscle injury, including Z-band streaming, increased blood CK and a decrease in force-generating capacity. Study 3 examined the potential for DT-MRI to detect structural changes in response to an acute bout of work, previously shown to induce muscle damage that more closely simulated normal endurance exercise. Subjects performed 45 min of downhill running (-10° grade) and DT-MRI revealed increased ADC and tensor eigenvalue λ3 24 h post-exercise compared to baseline, in addition to increased plasma CK and decreased force-generating capacity. The main finding from the thesis is the application of DT-MRI to non-invasively detect exercise-induced changes in skeletal muscle structure as verified using well understood direct and indirect measures of muscle damage.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: STRATEGIES TO MAXIMIZE SKELETAL MUSCLE PROTEIN SYNTHESIS  IN OLDER ADULTS

contributor:
Phillips, Stuart M
Kinesiology

subject: Muscle Protein Aging Leucine

abstract: There is a saturable, dose-response relationship between the amount of protein ingested at a meal, the ensuing hyperaminoacidemia, and the subsequent skeletal muscle protein synthesis (MPS) response. Imposition of an external load, usually practiced as resistance exercise, on skeletal muscle is also a potent stimulus for increasing MPS and adds synergistically to the hyperaminoacidemia-induced rise in MPS. The current thesis examined the potential for meal-focused protein/leucine intake strategies, alone and in combination with resistance exercise, to augment MPS in older men. MPS was measured acutely (hours) using the continuous infusion of L-[ring-13C6]phenylalanine (Study 1) or over longer-term, integrated periods via ingestion of deuterated water (Study 2: 2-wk and Study 3: 3-d) while participants were free-living. In Studies 1 and 2 we examined whether a balanced versus a skewed pattern of protein intake across daily meals would enhance MPS during energy restriction (ER) in overweight/obese older men. Study 1 showed that a balanced consumption of protein during ER stimulated acute (%/h) myofibrillar protein synthesis (MyoPS) more effectively than a traditional, skewed distribution. Combining resistance training (RT) with a balanced protein intake pattern restored the lower acute rates of MyoPS during ER to the higher levels observed in energy balance. Study 2 showed no effect of daily protein intake pattern during ER on longer-term integrated MyoPS (%/d). However, the inclusion of RT during ER enhanced integrated MyoPS and the synthesis of numerous individual contractile, sarcoplasmic and mitochondrial skeletal muscle proteins with both protein intake patterns. Study 3 showed that leucine co-ingestion with daily meals enhanced integrated (%/d) MyoPS in healthy older men who were in energy balance and was equally effective among those consuming higher (1.2 g/kg/d) and lower (0.8 g/kg/d) protein intakes. Furthermore, the stimulatory effect of leucine co-ingestion on integrated MyoPS was further potentiated with the performance of resistance exercise. Collectively, these studies support the potential for per-meal recommendations, optimizing the protein dose consumed on a per-meal basis and leucine co-ingestion with meals, to augment MyoPS in older men, especially when combined with RT. These data have implications for recommendations to optimize MyoPS and possibly muscle mass in aging persons.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Elucidation of IAP1's Role in Age-Related Resistance and Other Disease Resistance Pathways in Arabidopsis

contributor:
Cameron, Robin K.
Biology

subject: age, resistance, disease, pathways, arabidopsis, mutant, species

abstract: Age-Related Resistance (ARR) has been observed in numerous plant species, resulting in increased disease resistance as the plant matures. The ARR defective mutant, iap1-1, (important in the ARR Pathway,) was discovered in an ARR mutant screen and EDS1, (enhanced disease susceptibility,) which is involved in other disease resistance pathways, was shown to be required for ARR. lntercellular accumulation of salicylic acid (SA) is required for ARR suggesting that SA may act as an anti-microbial agent. Mature (6 wpg) iap1-1 does not accumulate intercellular or intracellular SA in response to Pst inoculation. lntercellular and intracellular SA accumulation is also partially reduced in young (4 wpg) plants during R gene-mediated resistance to Pst(AvrRpt2) which is partially compromised suggesting that the two pathways share common elements. The novel discovery of the presence of intercellular SA during R gene-mediated resistance suggests that it may act as an antimicrobial agent during R gene-mediated resistance as it is hypothesized to during ARR. The iap1-1 mutation maps to chromosome four between 17,938,268bp and 18,133,423b. The semi-dominant, loss of function nature of the iap1-1 mutation suggests that IAP1 is a positive regulator in the ARR pathway.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Non-targeted radiation effects in esophageal adenocarcinomas

contributor:
Mothersill, Carmel
Medical Physics

abstract:
The primary aim of this thesis is to investigate non-targeted radiation effects (NTE) in cancer patients undergoing radiotherapy. One of the main NTE being studied was radiation- induced bystander effects (RIBE). A pre-existing research project was being conducted on esophageal adenocarcinoma cancer (EAC) patients at our local Juravinski Cancer Centre
(JCC). High dose-rate (HDR) brachytherapy is a specific type of radiotherapy used to treat advanced stages of esophageal cancer. One study followed 15 esophageal cancer patients throughout their entire fractionated brachytherapy by using a number of sample based colony-forming assays. Another study investigated 60 esophageal cancer patients’ responses to a single exposure of brachytherapy by using a blood serum based colony-forming assay. The mechanisms underlying RIBE have remained elusive to date. Serotonin dependent mechanisms have been shown to have a role in radiation-induced bystander signaling and response pathways for human keratinocytes and breast cancer cells, but there are no previous studies investigating bystander effects in esophageal cancer. Overall thesis findings are summarized below:
Q1:Are bystander effects produced in brachytherapy patients?                                           Yes, they are produced in non-smokers
Q2:Are they detectable in non-tumour samples such as blood and urine?                             Yes, best in blood samples                                                                                Q3:Is serotonin involved in the mechanism in patient samples and EAC cells ?                Serotonin was important in some patient samples but not in the two cell lines                    Q4:Do they persist during fractionated treatments?                                                             Yes, an adaptive response initiated in bystander cells
Q5:Are available esophageal cell lines useful for studying bystander effects?
Yes, EAC cells produce bystander signals
￼￼￼This thesis may contribute to the knowledge on bystander or even abscopal effects in radio- therapy. The investigations presented in this thesis motivates other research to identify the propagated soluble factors that promote radiation-induced signaling pathways in esophageal cancer, to develop risk based radiation exposure guidelines, and to develop clear bioassays and biomarkers for bystander effects.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: A Comparative Study of Techniques for Estimation and Inference of Nonlinear Stochastic Time Series

contributor:
Bolker, Benjamin
Mathematics and Statistics

subject: Forecasting, Time series, Estimation, Fitting

abstract: Forecasting tools play an important role in public response to epidemics. Despite this, limited work has been done in comparing best-in-class techniques across the broad spectrum of time series forecasting methodologies. Forecasting frameworks were developed that utilised three methods designed to work with nonlinear dynamics: Iterated Filtering (IF) 2, Hamiltonian MCMC (HMC), and S-mapping. These were compared in several forecasting scenarios including a seasonal epidemic and a spatiotemporal epidemic. IF2 combined with parametric bootstrapping produced superior predictions in all scenarios. S-mapping combined with Dewdrop Regression produced forecasts slightly less-accurate than IF2 and HMC, but demonstrated vastly reduced running times. Hence, S-mapping with or without Dewdrop Regression should be used to glean initial insight into future epidemic behaviour, while IF2 and parametric bootstrapping should be used to refine forecast estimates in time.

abstract: Thesis

abstract: Master of Science (MSc)


title: Standard Model Naturalness from Dark Vortices and Codimension-2 Braneworlds

contributor:
Burgess, Cliff
Physics and Astronomy

abstract: There are numerous models of new physics that posit extra dimensions with characteristic length scale much larger than the inverse TeV scale. These so-called models of large extra dimensions can be used to confront the hierarchy problems that plague the standard models of particle physics and cosmology, as the usual arguments about hierarchy problems can be evaded if there are new physics scales and new dynamics in the extra dimensions. This thesis investigates a class of 6D models where the size of the two extra dimensions is exponentially sensitive to the value of a bulk zero mode, allowing a large hierarchy of scales to be generated if the zero mode is stabilized at a modestly large value. In general, scale invariance in the bulk forces the zero mode potential to have a runaway (or flat) form, so localized brane sources are added to the system which explicitly break the scale invariance and stabilize the zero mode. Brane physics can be chosen so that this stabilization naturally happens at values that give micron-sized extra dimensions, as desired in models of large extra dimensions that solve the electroweak hierarchy problem. These models are also interesting because they can predict a 4D curvature that is suppressed relative to the mass scale of the brane physics, thereby making progress on the cosmological constant problem by separating the 4D particle physics scale from the scale of the observed 4D vaccuum energy. This suppression is technically natural because the curvature vanishes in the limit that the branes are scale invariant, though this is also the limit in which the runaway potential for the zero mode reappears. This thesis also constructs the correct 4D effective theory that describes the system when length scales of interest are much larger than the size of the extra dimensions, and an effective field theory approach is also adopted to study the Higgs phenomenology of these models at higher energies.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: IDENTIFYING RNA BIOMARKERS OF CEREBROVASCULAR DISEASE

contributor:
Paré, Guillaume
Medical Sciences

subject:
blood
biomarker
gene expression profiling
stroke
diagnosis
prognosis
atrial fibrillation

abstract: Stroke is an acute neurological deficit that results from abnormal blood flow to the brain. The term stroke encompasses two primary subgroups: hemorrhagic stroke that is due to extravasation of blood and ischemic stroke that is due to vessel obstruction. Determining stroke type and underlying etiology is a crucial step in patient management as it influences treatment strategies. Currently diagnosis of stroke relies on clinical examination and neuroimaging, but there is a lack of rapid diagnostic and prognostic testing. Using microarray technology we identified a novel association between elevated peripheral blood expression of MCEMP1 and stroke. We have also shown that MCEMP1 discriminates between primary stroke types and predicts one-month post-stroke prognosis. Since genetic mechanisms underlying stroke remain incompletely understood we next conducted a global gene network analysis. Network analysis identified four large groups of co-expressed genes associated with ischemic stroke. NLRC4, CKLF, and HS.546375 were the most interconnected genes within unique modules and each was also independently associated with ischemic stroke. We show that multi-gene models have greater discriminative capacity for stroke and stroke prognosis, than single gene models. In addition to stroke biomarkers we also identified biomarkers of atrial fibrillation (AF), a known risk factor of stroke. Currently our understanding of the molecular mechanisms underlying AF remains incompletely understood. Thus we conducted whole blood expression profiling in patients with persistent AF before and after successful electrical cardioversion, a procedure that aims to restore sinus rhythm to the heart. We identified elevated expression of SLC25A20 and PDK4 during AF as compared with sinus rhythm. Furthermore we show that SLC25A20, PDK4 and NT-proBNP have incremental utility to discriminate AF from sinus rhythm. Taken together, the thesis implicates new genes with stroke and AF, and also indicates that whole blood RNA biomarkers may have clinical utility.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: User-Centred Requirements Analysis and Evidence-Informed Design Solutions for a Chronic Disease Self-Management System

contributor:
Archer, Norm
eHealth

abstract: Chronic diseases consume over 40% of the direct costs of healthcare in Canada.  It is therefore imperative to limit or reduce this financial burden in order to maintain or improve the quality that Canadians expect from their healthcare system.  One way to do this is to devise cost-effective ways to help patients manage their own chronic illnesses better in collaboration with their circles of care (caregivers, care providers, and others who help to care for patients).  Providing online support that assists chronically ill patients has been shown to be effective in many scientific studies.  Since there are many characteristics of chronic illnesses that are similar, high quality online support is adaptable to a variety of chronic illnesses (e.g. heart disease, diabetes, kidney disease, etc.). This study focuses on the design of an online self-care application MyPADMGT for one specific chronic disease, Peripheral Arterial Disease (PAD), which clinicians, patients with PAD, their informal caregivers, and allied healthcare professionals can use to support and improve patient self-care, potentially leading to better quality of life. Approximately half a million people in Canada suffer from PAD, so this approach to dealing with just this one debilitating chronic disease could give a boost to quality of life for a significant number of patients. This approach is generalizable to patient support for many other chronic illnesses.  In this study, using the Persona-Scenario Method, PAD surgeons, patients and their informal caregivers were asked to create Personas and describe the Scenarios in which Personas would interact with the MyPADMGT online application. The results were used to identify patterns in user requirements and preferences, leading to the appropriate evidence-informed design solutions for MyPADMGT.

abstract: Thesis

abstract: Master of Science (MSc)


title: Modelling Concurrent Systems with Interval Processes

contributor:
Janicki, Ryszard
Computing and Software

subject:
Computer Science
Theoretical Computer Sceince
Systems Modelling
Concurrency

abstract:
Standard operational semantics of the majority of concurrency models is defined
in terms of either sequences or step sequences, while standard concurrent history
semantics is usually defined in terms of partial orders, stratified order structures (or
structures equivalent to them as net processes).
It is commonly assumed (first argued by N. Wiener in 1914) that any system run
(execution) that can be observed by a single observer must be an interval order of
event occurrences.
However, generating interval orders directly is problematic for most models of
concurrency, as the only feasible sequence representation of interval order is by using
Fishburn Theorem (1970) and appropriate sequences of beginnings and endings of
events involved. It was shown by Janicki and Koutny in 1997 that concurrent histories
involving interval orders can be represented by interval order structures, but how these
interval order structures could be derived for particular concurrent systems was not
clear.
My original contribution to knowledge is defining an interval order semantics for
Petri Nets with Inhibitor Arcs. We start with introducing operational interval order
semantics, and then we generalize the concept of net process to represent the set of
equivalent executions modelled by interval orders.
Next we will show that our interval processes correspond to appropriate interval
order structures. Finally, we will prove that our model is equivalent to that of Janicki
and Yin (2015) where novel interval traces are used to represent equivalent executions.
We will also demonstrate that our model covers simpler cases where sequences or
step sequences were used to represent system runs.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: SVSF Estimation for Target Tracking with Measurement Origin Uncertainty

contributor:
Habibi, Saeid
Mechanical Engineering

subject: estimation, smooth variable structure filter, target tracking, measurement origin uncertainty

abstract:
The main idea of this thesis is to formulate the smooth variable structure filter (SVSF) for target tracking applications in the presence of measurement origin uncertainty. Tracking, by definition is the recursive estimation of the states of an unknown target from indirect, inaccurate and uncertain measurements. The measurement origin uncertainty introduces the data association problem to the tracking system.
The SVSF estimation strategy was first presented in 2007. This filter is based on sliding mode concepts formulated in a predictor-corrector form. Essentially, the SVSF uses an existence subspace and smoothing boundary layer to bind the estimated state trajectory to within a subspace around the true trajectory. The SVSF is demonstrated to be robust to modeling uncertainties and provide extra measures of performance such as magnitude of the chattering signal. Therefore, with respect to specific nature of car tracking problems that involves modeling uncertainty, it was hypothesized that a robust estimation strategy such as the SVSF, would improve the performance of the tracking system and give more robust tracking results. Also, having the extra information provided by the SVSF strategy, i.e. the chattering magnitude signal, would lead to algorithms that could better account for measurement origin uncertainty in the context of the data association process. Further to these hypotheses, this research has focused on investigating the performance of the SVSF in the target tracking problems, advancing the development of the SVSF, and employing its characteristics to deal with data association problems.
The performance of the SVSF, in its current form, can be improved when there is fewer measurements than states by using its error covariance in target tracking.
As the first contribution in this research, the SVSF is formulated in the context of target tracking in clutter and combined with data association algorithms, resulting in the SVSF-based probabilistic data association (PDA) and joint probabilistic data association (JPDA) for non-maneuvering and maneuvering targets. The results are promising in the tracking scenarios with modeling uncertainties. Therefore, the thesis is then expanded by generalizing the covariance of the SVSF for the cases where the number of measurements is less than the number of states. The generalized covariance formulation is then used to derive a generalized variable boundary layer (GVBL) SVSF. This new derivation gives an estimation method that is optimal in the MMSE sense and in the meantime preserves the robustness of the SVSF. The proposed algorithm improves the performance measures and makes a more reliable tracking algorithm.
This thesis explores the hypothesis that multiple target tracking performance can be substantially improved by including chattering information from SVSF-based filtering in the data association method. A Bayesian framework is used to formulate a new set of augmented association probabilities which include the chattering information. The simulation and experimental results demonstrate that the proposed augmented probabilistic data association improves the performance of the tracking system including maneuvering cars, in particular for highly cluttered environments.
The derived methods are applied on simulations and also on real data from an experimental setup. This thesis is made up of a compilation of papers that include three conference papers and three journal papers.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Uses of Conversational Speech in Measuring Language Performance and Predicting Behavioural and Emotional Problems

contributor:
Humphreys, Karin R.
Psychology

subject: speech, language, emotional, conversational, problems, symptoms

abstract:
 Challenges to the diagnostic accuracy of standardized tests of language can make the utility of these measures on their own, problematic. Consequently, this research program uses tools of conversational analysis to study the speech of preschoolers and young adults.

 In the first of three studies we examine, from a purely data-driven approach, how conversational measures relate to one another and compare with WPPSI-III expressive and receptive vocabulary scores in assessing preschoolers' language. Mean length of utterance (MLU) was found to be the only conversation measure strongly related to WPPSI-III language scores. However, other conversation measures constituted reasonably stable factors that may have utility for children's language assessment.

 The second study uses the same sample of children to investigate what features of language best predict behavioural and emotional problems and whether conversation measures provide better prediction of these symptoms than standardized scores. Results indicated that conversation measures of language significantly improved prediction of Child Behavior Checklist (CBCL C-TRF) DSM-oriented and syndrome scales beyond that accounted for by WPPSI GLC scores.

 Finally, the third study uses conversational analysis to study the role of
disfluencies in the speech of young adults with and without autism spectrum disorders
(ASDs) to determine whether these features of speech serve listener or speaker-oriented functions. Individuals with ASD were observed to produce fewer filled pause words (ums and uhs) and revisions than controls, but more silent pauses. Filled-pause words, therefore, appear to be listener-oriented features of speech.

 Taken together, findings of this program of research highlight the importance of
using conversational analysis as an alternative or in addition to standardized tests of
language as well as inform what specific measures of language are best suited for this
purpose.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: VERIFICATION, COMPARISON AND EXPLORATION: THE USE OF SENSITIVITY ANALYSES IN HEALTH RESEARCH

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
Sensitivity Analyses
Meta-analysis
Correlated discrete choice data
Both-armed zero-event
Bayesian approach
Rare event

abstract:
Background and Objectives:
I investigated the use of sensitivity analyses in assessing statistical results or analytical approaches in three different statistical issues: (1) accounting for within-subject correlations in analyzing discrete choice data, (2) handling both-armed zero-event studies in meta-analyses for rare event outcomes, and (3) incorporating external information using Bayesian approach to estimate rare-event rates.

Methods:
Project 1: I empirically compared ten statistical models in analyzing correlated data from a discrete choice survey to elicit patient preference for colorectal cancer screening. Logistic and probit models with random-effects, generalized estimating equations or robust standard errors were applied to binary, multinomial or bivariate outcomes.
Project 2: I investigated the impacts of including or excluding both-armed zero-event studies on pooled odds ratios for classical meta-analyses using simulated data. Five commonly used pooling methods: Peto, Mantel-Haenszel fixed/random effects and inverse variance fixed/random effects, were compared in terms of bias and precision.
Project 3: I explored the use of Bayesian approach to incorporate external information through priors to verify, enhance or modify the study evidence. Three study scenarios were derived from previous studies to estimate inhibitor rates for hemophilia A patients treated with rAHF-PFM: 1) a single cohort of previously treated patients, 2) individual patient data meta-analysis, and 3) an previously unexplored patient population with limited data.

Results and Conclusion:
Project 1: When within-subject correlations were substantial, the results from different statistical models were inconsistent.
Project 2: Including both-armed zero-event studies in meta-analyses increased biases for pooled odd ratios when true treatment effects existed.
Project 3: Through priors, Bayesian approaches effectively incorporated different types of information to strengthen or broaden research evidence.
Through this thesis I demonstrated that when analyzing complicated health research data, it was important to use sensitivity analyses to assess the robustness of analysis results or proper choice of statistical models.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: New Techniques Facilitate the Discovery and Study of Modular Microbial Natural Products

contributor:
Nathan, Magarvey
Biochemistry and Biomedical Sciences

abstract:
Microbial natural products have been one of the most important sources of drugs for the last century. However, as increasing numbers of natural products were discovered, researchers increasingly found previously described compounds, leading to a decline in efficiency and perceived future prospects for natural products discovery. Now, we know from genome sequencing that massive numbers of natural products remain to be discovered, indicating that new strategies and techniques may be required to leverage new bio- and chemo-informatic data to reveal these previously undiscovered small molecules.
First, I developed an automated database search strategy that could reveal natural products in liquid chromatography coupled mass spectrometry (LCMS) data based on the in silico fragmentation of automated structure predictions based on genome sequence inputs. This Genomes-to-Natural Products pipeline (GNP) was used as an automated approach for uncovering new modular microbial natural products, identifying structures from cryptic biosynthetic gene clusters as well as from organisms which had not been known to produce natural products previously. Next, I generated a comprehensive library of microbial antibacterial natural products and used a retrobiosynthetic algorithm to identify chemical families with conserved mechanisms of action. This approach led to investigations of the telomycin family of antibiotics, revealing that this old molecule has a novel target. Finally, I led two targeted investigations of organisms that had been identified as potential natural product producers via bioinformatic analysis, revealing new chemical compounds from Legionella and Delftia. Throughout this thesis, bio- and chemo-informatics have been used to illustrate new approaches to natural products research, generating novel platform technologies and investigating untouched organisms as a means of rediscovering the potential of microbial natural products.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Gamification of Mobile Educational Software

contributor:
Anand, Christopher
Computing and Software

subject: gamification, education, tablet computers, mobile computers, user interface design, human-computer interaction, literacy, adult literacy

abstract:
The overall theme of this thesis is the study of incorporating gamification design approaches in the creation of mobile educational software. The research presented in this thesis focuses on the design and testing of software created to teach introductory computer science and literacy concepts to postsecondary and adult learners. A study testing the relative effectiveness and subjective user enjoyment of different interfaces for a mobile game is also included in this thesis, as the results of the study led to the primary research objectives investigated in further studies. Our primary research objective was to investigate whether using gamification design approaches to mobile educational software could result in student engagement and learning. Our central hypothesis is that gamification design approaches can be used to create engaging and educationally effective mobile educational software. Our secondary research objective is to determine how mobile educational software can be made more or less engaging and educationally effective through gamification design approaches, by trying different approaches, testing the resulting applications, and reporting the findings. Three studies were conducted based on these objectives, one study to teach various computer science concepts to students in a first year computer science course with iPad applications, and two studies which used iPad applications to teach punctuation and homonyms, and improve reading comprehension. The studies document the design of the applications, and provide
analysis and conclusions based on the results of testing. Through the results of these studies we affirm our hypothesis. We make design suggestions for software creators, such as providing corrective feedback to the user. We discuss common themes that emerged across the studies, including how to best use educational software. Finally, as avenues for future work, we suggest investigating the impromptu social effects of using tablet software in a classroom, and the development of a usability testing platform.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: The overall theme of this thesis is the study of how gamification can be used to make mobile educational software engaging and effective as a learning tool. The research presented in this thesis focuses on the design and testing of software intended to teach introductory computer science and literacy concepts. The hypothesis guiding this work is that mobile educational software can be made engaging and educationally effective by incorporating game design elements. Through four studies we affirm our hypothesis, and document the relative success of various gamification techniques in different contexts. We make design suggestions for software creators, such as providing corrective feedback to the user. We discuss common themes that emerged across the studies, including how to best use educational software. Finally, as avenues for future work, we suggest investigating the impromptu social effects of using tablet software in a classroom, and the development of a usability testing platform.


title: IDENTIFICATION AND CHARACTERIZATION OF SMALL MOLECULE MODULATORS OF BCL-2 FAMILY PROTEINS

contributor:
Andrews, David
Biochemistry and Biomedical Sciences

abstract: Apoptosis is a tightly regulated form of cell death fundamental to multi-cellular organisms for maintaining cellular homeostasis and removing damaged or dangerous cells. Disruptions in the apoptotic pathway that result in excessive or insufficient apoptosis are associated with many conditions including cancer, auto-immune diseases and neurodegenerative diseases. The Bcl-2 family proteins are the central regulators and executors of apoptotic signals at the mitochondrial outer membrane (MOM). Permeabilization of the MOM by the Bcl-2 family proteins, Bax and Bak, marks commitment to death and is considered to be the point of no return for most cells. Therefore, restoring normal apoptosis by targeting the Bcl-2 family proteins represents a potentially important avenue for novel therapeutics. Small molecules targeting Bcl-2 family proteins are important for mechanistic studies and serve as potential leads for novel therapeutics. The findings presented in this thesis were focused on identifying and characterizing small molecules that promote or inhibit Bax and/or Bak mediated MOM permeabilization. Four small molecules, MSN-50, MSN-125, OICR766A and SRI-O13 were identified by screening compound libraries for molecules that inhibit or promote Bax mediated permeabilization. MSN-50 and MSN-125 inhibit Bax and Bak mediated membrane permeabilization and confer protection of cells against apoptotic stimuli. The compounds inhibit Bax mediated MOMP by disrupting partial, but not all, interfaces of the Bax dimer. OICR766A activates Bax by a mechanism distinct from activator BH3 proteins and cysteine 126 of Bax is required for activation by this compound. SRI-O13 enhances Bax and Bak mediated MOM permeabilization and displays anti-tumor activity in mice. Additionally, SRI-O13 synergizes with various apoptosis inducing agents to promote MOM permeabilization. Taken together, this work has increased the understanding of the mechanisms and interactions of Bcl-2 family proteins highlights the benefits of pharmacologically targeting Bcl-2 family proteins.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Investigating the Effect of Thermal Stresses on the Hollow Glass Microsphere/Polyester Composites Interfacial strength by Acoustic Emission Method

contributor:
Thompson, Michael
Chemical Engineering

subject: Interfacial Strength, Acoustic Emission, Hollow Glass Microsphere-Polyester composite, Frequency content analysis, Sheet molding compound

abstract:
The effect of coatings on the interfacial strength of a hollow glass microsphere/polyester composite and their capacity to endure thermal stresses were studied by mechanical testing and an active Acoustic Emission (AE) method. AE was postulated to provide more local information at or near the glass/polyester interface due to the sensitivity of elastic waves to the rigidity of polymer chains at the glass sphere/polyester interface compared to mechanical testing.
Three frequency ranges identified by multivariate statistics yet consolidated for the initial analysis into a band of 140-240 kHz, were found to be changing with the different coated glass filler for different glass content and heating state. Considering the acoustic behavior of the composites containing different levels of glass sphere content (1-10 vol%), a lower concentration (aminoethylamino)-propyl-trimethoxy silane coated glass (AS6), demonstrated the lowest attenuation after heating (associated with higher interfacial strength). As anticipated, the highest attenuation after heating was observed for uncoated glass (16K) due to expectedly weaker associations. Mechanical testing results after heating were consistent with the AE response for AS6 and 16K for this frequency range. Trends in amplitude for the three narrower, frequency ranges of 130-160 kHz, 180-220 kHz and 230-260 kHz were compared against that of 140-240 kHz and very small differences were observed. It was found that the frequency range of 130-60 kHz was more descriptive of the changes of interfacial strength in composites (at 10 vol%), being consistent with the mechanical test results. Considering the AE response at 130-160 kHz and mechanical data, higher concentration (aminoethylamino)-propyl-trimethoxy silane (AS12), better endured thermal stresses compared to other coatings. A smaller trial looked at the effect of moisture aging and subsequent thermal cycling on the glass/polymer interface strength as another method to perturb the interface. Attenuation for the band of 180-260 kHz was studied for aged versus non-aged composites. The commercial coating, L21 demonstrated a better moisture resistance before and after thermal cycling compared to uncoated glass spheres.
An improved evaluation of interfacial strength in glass/polyester was expected using AE technique versus mechanical testing due to its higher sensitivity to changes in internal structure, however; no significant improvement compared to mechanical testing was observed, at least based on the analysis technique currently being used.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: Sheet molded compound (SMC) is a polymer material reinforced by fibers providing a combination of light weight and high mechanical properties and is used in automotive industry. Light weight fillers (hollow glass microspheres) are used to obtain further weight reduction; however, addition of these fillers leads to reduced mechanical properties and further problems during painting process known as ‘paint popping’. The former is due to uncertain interfacial state between polymer and fillers and the latter results from different thermal expansion behavior of the polymer and filler materials while the material is exposed to high temperatures for painting process. This research aims to devise a highly sensitive technique and evaluate its suitability compared to mechanical testing for investigation of the origin of aforementioned problems. Acoustic Emission (AE) is a method with high sensitivity to changes in internal structure of the material which is postulated to provide a better insight on material microstructure compared to more commonly used method i.e. mechanical testing. Use of interfacial controlling agents was examined to reduce the problems as a result of introduction of fillers. The effect of using surface modified fillers and the effect of thermal stresses on material was investigated using AE technique. Application of AE method in this study provided a good insight about the changes in material internal structure; however, it did not demonstrate a significant improvement in detecting the origins of studied problems compared to mechanical testing at least based on the analysis technique used in this study.


title: OPTIMIZING POLYMER ASSISTED DEWATERING IN RECUPERATIVE THICKENING VIA A LAB-SCALE SYSTEM FOR ENHANCED BIOGAS PRODUCTION IN ANAEROBIC DIGESTION PROCESSES

contributor:
Latulippe, David
Chemical Engineering

subject:
Anaerobic Digestion
Dewatering
Polymer Optimization
Biogas Production

abstract: There is growing interest in the use of high performance anaerobic digestion (AD) processes for the production of biogas at wastewater treatment facilities to offset the energy demands associated with wastewater treatment.  Recuperative thickening (RT) is a promising technique which involves recycling a portion of the digested solids back to the incoming feed.  In general there exists a significant number of knowledge gaps in the field of RT because the studies that have been conducted to date have almost exclusively occurred in pilot or full scale trials; this approach greatly limits the amount of process optimization that can be done in a given trial. In this work, a detailed and comprehensive study of RT processes was conducted at the lab scale; a demonstration of the optimization of polymer assisted dewatering is given and biogas production and quality monitored. Two custom designed digesters (capacity = 1.5 L) were operated in parallel with one acting as a ‘control’ digester and the other operating under a semi-batch RT mode; both digesters were also operated in parallel under RT with alternative polymer flocculants.  There were no significant changes in the overall biogas methane composition; however the RT digester had an average biogas productivity over two times higher than the control one.  It was found that the recycling of the polymer flocculant back into the RT digester resulted in a significant improvement in dewatering performance.  At the highest polymer concentration tested, all polymer flocculants demonstrated equivalent dewatering performance achieving over 6 times lower CST’s than the control; at lower polymer concentrations the 4516 polymer flocculant had superior dewatering performance. Thus, there exists an opportunity to decrease the overall consumption of polymer flocculants through judicious selection of the flocculant and the dose that is used both for the thickening and end-stage dewatering processes in RT digesters.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: In wastewater treatment (WWT), solid wastes are treated using a technique called anaerobic digestion (AD) which involves the conversion of solids in biogas by anaerobic bacteria. Biogas is a mixture of mostly methane and carbon dioxide and can be used as a fuel source for energy production. There’s growing interest in the use of high performance AD processes for the production of biogas at WWT facilities to offset the energy demands associated with WWT.  Recuperative thickening (RT) is a promising technique which involves recycling a portion of the digested solids back to the digester. In this work, a detailed and comprehensive study of RT processes was conducted at the lab scale; a demonstration of the optimization of polymer assisted dewatering is given and biogas production and quality monitored. Two 1.5 L custom designed digesters were operated in parallel one as a ‘control’ and the other operating under a semi-batch RT.


title: Studies on the Pathophysiology of Cancer-Induced Depression

contributor: Medical Sciences (Division of Physiology/Pharmacology)

subject:
depression
cancer
hippocampus
medial prefrontal cortex
RNA-sequencing
Sholl analysis
glutamate
system xc-
inflammation
cytokines
dendritic atrophy
antidepressant
fluoxetine
corticosterone

abstract: Despite the lack of robust clinical response, treatment strategies for cancer-induced depression (CID) are currently limited to those developed for non-cancer-related depression. The work presented in this dissertation conceptualizes CID as a pathophysiologically distinct form of depression. To investigate CID at the most basic level, we first developed a preclinical model that was validated by comparison to an established model of stress-induced depressive-like behaviours. The positive control model was developed by chronically treating female BALB/c mice with oral corticosterone (CORT). The CID model was developed using subcutaneous inoculation with 4T1 mammary carcinoma cells. Anhedonia, behavioural despair, and dendritic atrophy in the medial prefrontal cortex (mPFC) were observed in both models. Similar to many human cancer cell lines, 4T1 cells were shown to secrete significant amounts of glutamate, which was markedly attenuated using the system xc- inhibitor sulfasalazine (SSZ). In CID mice, oral treatment with SSZ was at least as effective as fluoxetine, a popular clinical antidepressant, at preventing depressive-like behaviours. This effect was primarily attributable to intact SSZ, rather than its anti-inflammatory metabolite. RNA-sequencing was performed on hippocampal samples from CID and CORT animals. Analysis of differential expressed genes (DEGs) revealed significant overlap between the two models. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and biological process gene ontologies (GO:BP) terms related to ion homeostasis and neuronal communication were enriched for both models. CID was associated with additional DEGs that were not identified in the CORT model. These DEGs were enriched in KEGG pathways and GO:BP terms related to neuronal development, intracellular signalling cascade, learning, and memory. These studies suggest that CID may involve a distinct aetiology, and that glutamate secretion by cancer cells presents a viable target for antidepressant treatment. The development of mechanism-based therapeutics for CID will dramatically improve the quality of life for cancer patients.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Cancer patients are at a high risk of developing depression. In addition to the psychological stress caused by a cancer diagnosis, there is evidence that cancer causes depression through biological pathways. To investigate these pathways, a mouse model of cancer-induced depression (CID) was developed. This model showed comparable behavioural and structural brain deficits to those observed in a stress model of depression. Cancer cells secrete elevated levels of glutamate, a signalling molecule that is involved in depression. In CID mice, inhibiting glutamate release had an antidepressant effect similar to that of fluoxetine, a standard clinical antidepressant. A genetic analysis on brain samples from the CID model revealed significant overlap with the stress model of depression. CID mice had additional changes relevant to learning, memory, and brain cell development that were not detected in the stress model. A better understanding of CID will lead to better treatment strategies developed specifically for cancer patients.