title: Transgenerational and reproductive impacts of acute early-life radiation on the house cricket, Acheta domesticus

contributor:
Rollo, David
Biology

subject: Insect, Generational, Paternal, Radiation, Stress

abstract: Stress is ubiquitous for all organisms, however, impacts vary depending on type and strength of the stressor, as well as the organism’s tolerance. Currently, ionizing radiation is described by the “linear no threshold” model. However, considerable research suggests that a hormetic or threshold model may better describe radiation exposure. Using male house crickets the impacts of early-life radiation on life history and reproductive traits, molecular biomarkers, and trans-generational impacts were analyzed. Generally, radiation impacts were best described by non-linear modelling. Multiple aspects of sexual signalling were disrupted by radiation, and impacts emerged in F1 offspring through extended longevity and superior survivorship.

abstract: Thesis

abstract: Master of Science (MSc)


title: Inhibition of DNA Methyltransferase Induces Melatonin Receptor Expression in C6 Glioma Cells

title: Epigenetic Regulation of the Melatonin Receptor

contributor: Medical Sciences (Division of Physiology/Pharmacology)

subject: Epigenetics Melatonin Receptor Methylation

abstract: The multiple physiological effects of the indoleamine hormone melatonin, are mediated primarily by its two G protein-coupled MT1 and MT2 receptors.  Our group has shown an upregulation of melatonin receptors following treatment with histone deacetylase (HDAC) inhibitors, including valproic acid (VPA) and Trichostatin A, in cultured cells and/or in the rat brain.  VPA increases histone H3 acetylation at the MT1 gene promoter region in rat C6 glioma cells, indicating that this epigenetic mechanism underlies its upregulation of MT1 expression.  Since HDAC inhibitors can also alter DNA methylation, the possible involvement of this second major epigenetic mechanism in the regulation of MT1 expression, was examined.  C6 cells were treated with the DNA demethylating agent, azacytidine (AZA, 1 - 25 µM), for 24 or 48 hours.  Treatment of C6 cells with AZA caused a significant upregulation of MT1 mRNA expression, as compared with controls (DMSO 0.05%).  Moreover, treatment with AZA (10 or 20 µM) for 24 or 48 hours, suppressed or abolished DNMT1 protein expression, and inhibited DNMT1 mRNA expression, which indicates inhibition of the DNMT1 enzyme activity.  A combination of VPA and AZA caused a trend toward additive upregulation of the MT1 receptor. These results show that DNA demethylation plays a role in the regulation of the MT1 receptor, consistent with the well-known effects of this epigenetic mechanism on gene transcription.   Epigenetic regulation of melatonin receptor expression could provide a novel strategy for modulating the therapeutic effects of this hormone and its clinically relevant agonists, such as agomelatine, and could also provide avenues for enhancing the antioxidant, neuroprotective, oncostatic and other benefits of this hormone and its agonists.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The hormone, melatonin, is involved in maintenance of the sleep cycle, and has many neuroprotective effects, initiated by its binding to specific proteins called receptors.  Epigenetic or reversible chemical modifications which alter DNA, without changing its sequence, can alter the levels of these receptors.  This process can be modulated by drugs, which can increase levels of the melatonin receptor.  In this study, the drug 5-Azacytidine (AZA) was used to cause specific chemical changes to DNA, termed demethylation.  This thesis shows for the first time, that AZA causes an increase in melatonin receptors.  AZA’s ability to cause demethylation was confirmed by observing decreased levels of the protein responsible for DNA methylation, DNA methyltransferase.  Melatonin receptors in the brain exhibit changes in disorders such as Alzheimer’s and Parkinson’s disease.  Understanding the mechanisms underlying the regulation of these receptors could provide avenues for enhancing the neuroprotective benefits of melatonin and related drugs.


title: Software Approaches to Optimize Energy Consumption for a Team of Distributed Autonomous Mobile Robots

contributor:
Karakostas, George
Computing and Software

subject:
Multi-robot systems
Optimization
Energy consumption

abstract:
In recent years, we have seen the applications of distributed autonomous mobile robots (DAMRs) in a broad spectrum of areas like search and rescue, disaster management, warehouse, and delivery systems. Although each type of systems employing DAMRs
has its specific challenges, they are all limited by energy since the robots are powered by batteries which have not advanced in decades. This motivates the development of energy efficiency for such systems.

Although there has been research on optimizing energy for robotic systems, their approaches are from low-level (e.g., mechanic, system control, or avionic) perspectives. They, therefore, are limited to a specific type of robots and not easily adjusted to apply for different types of robots. Moreover, there is a lack of work studying the problem from a software perspective and abstraction.

In this thesis, we tackle the problem from a software perspective and are particularly interested in DAMR systems in which a team of networked robots navigating in a physical environment and acting in concert to accomplish a common goal. Also, the primary focus of our work is to design schedules (or plans) for the robots so that they can achieve their goal while spending as little energy as possible. To this end, we study the problem in three different contexts:

- Managing reliability and energy consumption tradeoff. That is, we propose that robots verify computational results of one another to increase the corroboration of outputs of our DAMR systems. However, this new feature requires robots to do additional tasks and consume more energy. Thus, we propose approaches to reach a balance between energy consumption and the reliability of results obtained by our DAMR systems.

- Extending the operational time of robots. We first propose that our DAMR systems should employ charging stations where robots can come to recharge their batteries. Then, we aim to design schedules for the robots so that they can finish all their tasks while consuming as little energy and time (including the time spent for recharging) as possible. Moreover, we model the working space by a connected (possibly incomplete) graph to make the problem more practical.

 - Coping with environmental changes. This path planning problem takes into account not only energy limits but also changes in the physical environment, which may result in overheads (i.e., additional time and energy) that robots incur while doing their tasks. To tackle the problem from a software perspective, we  first utilize Gaussian Process and Polynomial Regression to model disturbances and energy consumption, respectively, then proposed techniques to generate plans
and adjust them when robots detect environmental changes.

For each problem, we give a formal description, a transformation to integer (linear) programming, online algorithms, and an online algorithm. Moreover, we also rigorously analyze the proposed techniques by conducting simulations and experiments in
a real network of unmanned aerial vehicles (UAVs).

abstract: Thesis

abstract: Candidate in Philosophy


title: Voter Competency, Distributed Ledger Technology, and the Future of Democracy

contributor:
Sciaraffa, Stefan
Philosophy

subject:
Institutional Design
Democracy
Distributed Ledger Technology
Blockchain Technology

abstract: A great challenge for democracy is to account for the conflict between the ideal of self-governance and the capacity of the average person to participate in democratic decision-making. This challenge has led some observers to question the defensibility of democracy and consider other systems of social organization. I argue instead that the problem can be solved with a technologically enhanced version of Thomas Christiano’s choice of aims model of democracy. I begin by setting up the voter competency problem: I describe the ideals of democracy and the role that is ascribed to citizens under traditional accounts of democracy, then proceed to a discussion of the empirical evidence that shows how unlikely it is that voters could ever adequately perform such a role. While I consider a number of alternative democratic models which attempt to reconstruct the role of citizens in a way that is consistent with their capacities and with the democratic ideal of self-governance, I find that the choice of aims model strikes this balance in a way that is most tenable. Despite this, I argue that changes to the way information is distributed in modern democracies, to do with the rise of the internet, pose a serious threat to the viability of even this model, as it is becoming increasingly difficult for voters to ascertain reliable information. The second half of the thesis offers support to Christiano’s model in the form of technologically enhanced institutions. Chapter 3 provides a basic understanding of an emerging technology called distributed ledger technology, which offers a new paradigm for how information is stored, controlled, and distributed around society. The final chapter demonstrates how this technology can be used to strengthen democratic institutions so that citizens are able to truly be said to self-govern in a way that is consistent with their capacities.

abstract: Thesis

abstract: Master of Arts (MA)


title: Cohomogeneity One Einstein Metrics on Vector Bundles

contributor:
Wang, McKenzie
Mathematics and Statistics

subject:
Einstein metric
Special holonomy
Cohomogeneity one
Vector bundle

abstract:
This thesis studies the construction of noncompact Einstein manifolds of cohomogeneity one on some vector bundles.
Cohomogeneity one vector bundle whose isotropy representation of the principal orbit G/K has two inequivalent irreducible summands has been studied in [Böh99][Win17]. However, the method applied does not cover all cases. This thesis provides an alternative construction with a weaker assumption of G/K admits at least one invariant Einstein metric. Some new Einstein metrics of Taub-NUT type are also constructed.
This thesis also provides construction of cohomogeneity one Einstein metrics for cases where G/K is a Wallach space. Specifically, two continuous families of complete smooth Einstein metrics are constructed on vector bundles over CP2, HP2 and OP2 with respective principal orbits the Wallach spaces SU(3)/T2, Sp(3)/(Sp(1)Sp(1)Sp(1)) and F4/Spin(8). The first family is a 1-parameter family of Ricci-flat metrics. All the Ricci- flat metrics constructed have asymptotically conical limits given by the metric cone over a suitable multiple of the normal Einstein metric. All the Ricci-flat metrics constructed have generic holonomy except that the complete metric with G2 holonomy discovered in [BS89][GPP90] lies in the interior of the 1-parameter family on manifold in the first case. The second family is a 2-parameter family of Poincaré–Einstein metrics.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Alkyne-Cobalt-Clusters: Syntheses, Structures and Rearrangements of Metal-Stabilized Propargyl Cations and Radicals

contributor:
McGlinchey, Michael J.
Chemistry

subject: alkyne, cobalt, clusters, syntheses, structures, rearrangements, metal-stabilized, cations, radicals, propargyl, reagents, linear, reaction, molecular

abstract:
 Cobalt-clusters are versatile reagents in organometallic chemistry. Their ability to protect an alkyne allows one to selectively manipulate a ligand without undergoing a competitive reaction from the alkyne. Cobalt-clusters geometrically modify linear alkynes to 136-145° degrees, thereby allowing for some non-traditional alkynyl chemistry to occur. In particular, the focus of this dissertation lies upon the chemistry of cobalt-complexed propargyl alkynols, the ability of cobalt to stabilize neighbouring cations generated from these alcohols, and the chemistry that can be accomplished by altering the steric and electronic effects. We have chosen to study the possibility of inducing migration of various substituents from one terminus of the cobalt-complexed alkyne to the alcoholic site of the propargyl group via protonation of the desired complex. While examining various silanes, and altering the propargyl alcohol itself, we have considered both steric and electronic effects, thereby determining the idealized conditions for such transfers to occur. Furthermore, in our attempts to successfully apply these migrations to several systems, we have acquired a diverse synthetic knowledge of propargyl cobalt-clusters and their intricate reactivity.

 An examination of the potential for allyl migrations in norbornyl derivatives revealed several fascinating transformations. Upon protonation with HBF4, [(2-endo-allyldimethylsilyl)ethynylborneol]Co2(CO)6, 63, suffers elimination of water or propene, to yield [(2-allyldimethylsilyl)ethynylborn-2-ene]Co2(CO)6, 68, [(2-endo-dimethylfluorosilyl)ethynylborneol]Co2(CO)6, 69, respectively, and, surprisingly, the tricobalt complex (2-norbornylidene)CHCCo3(CO)9, 70, In contrast, protonation of the terminal alkyne (2-endo-ethynylborneol)Co2(CO)6, 76, an anticipated precursor to 70, led
instead to (2-ethynyl-2-bornene)Co2(CO)6, 78, and the ring-opened species (2-ethynyl-4-isopropyl-1-methylcyclohexa-1,3-diene)Co2(CO)6, 79. However, conversion of 76 to 70 was achievable upon prolonged heating at reflux in acetone, thereby also affording the corresponding alcohol, [2-(2-hydroxybornyl)]CH2CCo3(CO)9, 77. A mechanistic rationale is offered for the formation of RCH2CCo3(CO)9 clusters upon protonation of alkyne complexes of the type (RC≡CH)Co2(CO)6.

 Our interest in acid-promoted rearrangements in cobalt-clusters led us to novel propargyl radical chemistry induced by using particular solvents. The protonation of (1,1-diphenyl-2-propyn-1-ol)Co2(CO)6, 108, with HBF4 in dichloromethane generates the expected metal-stabilized propargyl cation, and also rearranges to give the tricobalt cluster Ph2C=CH-CCo3(CO)9, 33. In contrast, use of THF as solvent affords the radical (Co2(CO)6)[HC≡C-CPh2·], which dimerizes at the methyne position; subsequent cyclization and carbonylation yields 2,5-bis-(diphenylmethylene)cyclopent-3-en-1-one, 112.

 Furthermore, use of a fluorenyl substituent, instead of the diphenyl analogue, has uncovered a route to transition-metal peroxides of general synthetic potential. Treatment of benzyl- or vinyl-dimethylsilylethynylfluoren-9-ol[Co2(CO)6], 53 and 54, respectively, with HBF4 in diethyl ether or THF has afforded the very first known bimetallic transition metal peroxides, 124 and 125.

 Finally, the ability of cobalt-clusters to alter the geometry of cycloalkanes has been investigated. Treatment of 1-[axial]-(trimethylsilylethynyl)cyclohexan-1-ol, 129, with dicobalt octacarbonyl results in a conformational ring flip such that the bulky dicobalt-alkyne cluster moiety now occupies the favored equatorial site. However, when a 4-tert-butyl substituent is present, the coordinated alkynyl group retains its original axial or equatorial position.

 Complexation of trans-[diaxial]-1,4-bis(triphenylsilylethynyl)cyclohexan-1,4-diol, 142, brings about a chair-to-chair conformational inversion such that both cluster fragments now occupy equatorial sites. In contrast, cis-1,4 bis(triphenylsilylethynyl)cyclohexan-1,4-diol, 143, reacts with Co2(CO)8 to yield the twist-boat conformer, 145, in which the two axial hydroxy substituents exhibit intra-molecular hydrogen bonding. Likewise, the corresponding reaction of cis-1 ,4bis(trimethylsilylethynyl)cyclohexan-1,4-diol, 147, with Co2(CO)8 leads to a twist-boat, 149, but, in this case, the molecules are linked through intermolecular hydrogen bonds. The importance of X-ray crystallography in the unambiguous determination of molecular conformations has been emphasized.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Enhancing Oncolytic Immunotherapy through Induction of Immunogenic Cell Death

contributor:
Mossman, Karen
Biochemistry

abstract: Oncolytic viruses (OVs) are natural or engineered viruses that specifically infect and kill cancer cells without harming healthy tissues. Cancer cells killed by OV infection expose tumor antigens along with viral components and intracellular factors that mediate inflammation. Ideally, this process elicits an anti-tumor immune response that controls tumor growth. Herpes simplex virus type 1 (HSV-1) is a candidate OV that has proven therapeutic efficacy in preclinical cancer models. However, therapeutic efficacy of current oncolytic HSV-1 (oHSV-1) is limited in immunologically hot cancers such as melanoma. Here we showed that oHSV-1 expressing a modified B-box (HMB) of high mobility group box 1 (HMGB1), a potent ligand of toll-like receptor (TLR) 4-MD2, provides marginal therapeutic benefit in mice bearing breast cancer. Comparing with parental oHSV, tumor-bearing mice treated with oHSV-1-HMB showed improved survival and reduced tumor burden. Our results demonstrated the potential to improve oHSV-1 with immunogenic cell death modulators. We anticipate our oHSV-1-HMB to provide additive benefit with the combination of immunological checkpoint blockade.

abstract: Thesis

abstract: Master of Science (MSc)


title: INVESTIGATING THE RELATIONSHIP BETWEEN CARDIORESPIRATORY FITNESS AND MEMORY IN OLDER ADULTS

contributor:
Heisz, Jennifer
Kinesiology

subject:
Cardiorespiratory fitness
Memory
Aging
Inflammation
Neurotrophic factors

abstract: Aging is associated with cognitive decline in various domains, including memory. The age-related increase in systemic inflammation has been identified as a potential mechanism contributing to these memory impairments. Specifically, elevated inflammation may impair neurotrophic factor production and function, which is important for maintaining brain health. Physical activity has been identified as a potential strategy for preventing or delaying memory decline, given its ability to reduce inflammation and stimulate neurotrophic factor expression. The present study investigated the relationship between cardiorespiratory fitness, a proxy for habitual physical activity, and memory in older adults. Inflammation and neurotrophic factors were examined as potential mechanisms mediating this relationship. Sixty-five community dwelling older adults (Mage = 70.6 ± 4.0) completed the Rockport 1-mile walk test to predict their cardiorespiratory fitness, as well as the Mnemonic Similarity Task to assess memory. Serum samples were collected to examine inflammatory markers, including interleukin-6 (IL-6), interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP), as well as neurotrophic factors, including brain derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1). No relationship was found between cardiorespiratory fitness and memory (p > .05). However, older adults with greater cardiorespiratory fitness had lower levels of IL-6 (p < .01) and TNF-α (p < .01) and trended towards higher levels of BDNF (p = .078). Furthermore, IL-6 was negatively correlated with IGF-1 (p < .01), suggesting higher inflammation may impair IGF-1 production. Contrary to our hypotheses, sequential mediation analyses revealed no indirect effect of inflammatory markers and neurotrophic factors on the relationship between cardiorespiratory fitness and memory. Our results suggest that cardiorespiratory fitness may promote favourable changes in inflammatory markers and neurotrophic factors, which—given previous literature—could help to support brain health with advancing age. More research is needed to further examine the relationship between cardiorespiratory fitness and memory.

abstract: Thesis

abstract: Master of Science (MSc)


title: Modeling Disease and Development with Pluripotent Stem Cells

contributor:
Draper, Jonathan
Biochemistry and Biomedical Sciences

abstract:
With recent advances in stem cell research, the use of human pluripotent stem cells (hPSC) provides access to disease-relevant cells that are not easily accessible in patients. The ability of hPSCs to self-renew indefinitely and to differentiate into cell types of all three embryonic germ layers provides a model system to investigate the effects of genetic mutations that are relevant in the context of specific diseases. hPSC carrying disease associated genetic mutations provide access to an unlimited supply of disease-relevant tissue while healthy hPSC can be used to model normal human development.
Our lab has access to samples from a family with multiple cases of pulmonary fibrosis (PF). The high prevalence of PF in this family led us to believe that there is a strong genetic component to the pathogenesis of PF in these cases. We previously were able to derive iPSC lines from each of the patients and have identified genetic variants via exome sequencing, including PACS1 and ITGB6, that may predispose carriers to PF. In the present study, we examine the phenotypic changes caused by the PACS1 and ITGB6 gene variants. We hypothesized that the N217S mutation in PACS1 conveys a resistance to apoptosis in fibroblasts which could lead to the accumulation of fibrotic tissue. This hypothesis was tested through the use of apoptosis assays including annexin flow cytometry and immunostaining for caspase 3 cleavage after treatment with TNF-related apoptosis-inducing ligands. We found that in transfected cell lines, there were no significant changes to apoptotic sensitivity. The results are inconclusive in the patient-derived fibroblasts because of high inter-test variability. The second mutation we examined was the R15K mutation in ITGB6, which occurs within the signal peptide. Thus, we hypothesized that this mutation affects the efficiency of localization and subsequently, function. This hypothesis was tested through confocal microscopy of endogenous ITGB6 in small airway epithelial cells (SAEC), as well as HEK 293 FT cells transfected with plasmid constructs containing GFP tagged wt or R15K ITGB6. We then tested for changes in the ability of ITGB6 to affect downstream signaling through plating on fibronectin, pulldown of focal adhesion kinase, and analysis for phosphorylated FAK through western blot. We found that endogenous expression of ITGB6 in SAECs, appears mainly in the membrane with a small percentage within the nuclear membrane.  In transfected cell lines, there was a shift in localization from plasma membrane to nuclear membrane. The functionality of ITGB6 did not appear to be affected based on our preliminary data.
This thesis also explores the utility of intestinal epithelial organoids derived from hPSCs, termed “human enterospheres” (hEnS), in investigating the process that drives intestinal maturation. The hEnS provide a unique novel model for studying maturation, due to the fetal phenotype of the hEnS. We hypothesized that through changes in culturing medium and addition of bacterial products, it is possible to induce maturation of the hEnS. To test this hypothesis, we cultured the hEnS with heat-killed bacteria that play a role in the natural maturation process and examined changes to markers of maturation. We also performed an in-depth study of key maturation markers at specific gestational stages. By immunostaining the gestational tissue for various markers associated with maturation, we sought to create a scale with which to evaluate the maturation status of hPSC-derived intestinal tissue.

abstract: Thesis

abstract: Master of Science (MSc)

abstract:
The development of human in vitro models has allowed for the application of basic knowledge of disease mechanisms previously established in animal models. Recent advances in stem cell technology have enhanced researchers’ ability to retrieve stem cells from patients in a non-invasive manner. Specific genetic changes found in these stem cells are often linked to specific diseases and provide unique opportunities to study disease progression outside of the human body (in vitro modelling). In our lab, we studied genes that may be linked to pulmonary fibrosis in order to determine the impact of these genes on the development and progression of this disease.
Previously, our lab has also been able to develop intestinal organoids, which are groups of cells that contain many of the cell types found in the human intestine. We sought to use these organoids to model human intestinal maturation by culturing them with native gut bacteria and examining any changes that occur. Development of these in vitro models will provide researchers with human models without the constant need for patient samples.


title: Methodologies for FPGA Implementation of Finite Control Set Model Predictive Control for Electric Motor Drives

contributor:
Nicolici, Nicola
Emadi, Ali
Electrical and Computer Engineering

subject:
fpga
field programmable gate array
fcs
finite control set
hdl
hardware description language
rtl
register transfer level
numerical precision
satisfiability modulo theories
mpc
model predictive control
word length optimization
electric drive
electric motor
permanent magnet synchronous motor
interval arithmetic
control system
digital control
inverter
fixed point
real time

abstract: Model predictive control is a popular research focus in electric motor control as it allows designers to specify optimization goals and exhibits fast transient response. Availability of faster and more affordable computers makes it possible to implement these algorithms in real-time. Real-time implementation is not without challenges however as these algorithms exhibit high computational complexity. Field-programmable gate arrays are a potential solution to the high computational requirements. However, they can be time-consuming to develop for. In this thesis, we present a methodology that reduces the size and development time of field-programmable gate array based fixed-point model predictive motor controllers using automated numerical analysis, optimization and code generation. The methods can be applied to other domains where model predictive control is used. Here, we demonstrate the benefits of our methodology by using it to build a motor controller at various sampling rates for an interior permanent magnet synchronous motor, tested in simulation at up to 125 kHz. Performance is then evaluated on a physical test bench with sampling rates up to 35 kHz, limited by the inverter. Our results show that the low latency achievable in our design allows for the exclusion of delay compensation common in other implementations and that automated reduction of numerical precision can allow the controller design to be compacted.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Examining the Inhibition Mechanism of EPAC

title: Inhibition Mechanism of EPAC

contributor:
Melacini, Giuseppe
Chemistry and Chemical Biology

subject:
EPAC
competitive inhibitor
inhibition mechanism
NMR Spectroscopy

abstract:
A novel partial agonist of the exchange protein activated by cAMP isoform 1
(EPAC1), I942, was recently discovered and shown to reduce the guanine exchange
factor activity of cAMP-bound EPAC1 to approximately 10% relative to cAMP
activation. However, the inhibition mechanism of I942 remains unknown. Here, we
utilize NMR spectroscopy to probe the inhibitory I942 - EPAC1 interactions at atomic
resolution. The EPAC1 - I942 interface was mapped through intermolecular NOEs
measured by 15N and 13C filtered NOESY-HSQC experiment. Intermolecular NOE
mapping combined with other protein NMR methods, such as saturation transfer
difference, transfer Nuclear Overhauser Effect spectroscopy and chemical shift mapping,
we revealed that I942 interacts with the phosphate binding cassette (PBC) and base
binding region (BBR) of the EPAC1 cyclic nucleotide binding (CNB) domain, similar to
cAMP. The PBC controls the conformation of the hinge region, and subsequently,
allosterically shifts the hinge region between its active/inactive states. Molecular
dynamics simulation based on the NMR spectroscopy data revealed that EPAC1-CNB
adopts an intermediate conformation between its inactive and active states, which
explains the partial agonist nature of I942.

abstract: Thesis

abstract: Master of Science (MSc)

abstract:
The exchange protein activated by cAMP (EPAC) is a receptor for the classical
secondary messenger cAMP. EPAC is present in multiple human systems and plays a
pivotal role in the development of a wide range of diseases. In this study, we aim to
establish the inhibition mechanism of a novel small molecule EPAC inhibitor/partial
agonist I942 using NMR spectroscopy with the goal of achieving a better understanding
of EPAC inhibition and paving the way for new small molecule EPAC inhibitors that can
potentially treat EPAC-related diseases such as heart failure and diabetes.


title: Schwinger Pair Production and Fall to the Center

contributor:
O'Dell, Duncan
Physics

subject: Pair production

abstract: The classical field theory of Schwinger pair creation can be described using an effective Schrodinger equation with an inverted harmonic oscillator Hamiltonian. It is a well known fact that the inverted harmonic oscillator admits a canonical transformation to a Q.P type Berry-Keating Hamiltonian. In this thesis we demonstrate that the classical field theory of Schwinger pair creation has a hidden scale invariance described by the quantum mechanics of an attractive inverse square potential in the canonically rotated (Q,P) coordinates of the inverted harmonic oscillator. The quantum mechanics of the inverse square potential is well known because of the problem of fall to the center and the associated ambiguities in the boundary condition. It is also well known as a description of the physics of pair creation in the presence of an event horizon and black hole decay. We use point particle effective field theory (PPEFT) to derive the boundary condition which describes pair creation. This leads to the addition of an inevitable Dirac delta function with imaginary coupling to the inverse square potential, describing the physics of the source. This non-hermitian physics leads to the Klein paradox. The conservation loss is due to the charged pairs being produced during tunneling.

abstract: Thesis

abstract: Master of Science (MSc)


title: EFFICIENT DATA ASSOCIATION ALGORITHMS FOR MULTI-TARGET TRACKING

contributor:
Kirubarajan, Thia
Electrical and Computer Engineering

subject:
Binary programming
Optimization
Multi-target tracking
assignment problem

abstract: Efficient multi-dimensional assignment algorithms and their application in multi-frame tracking

abstract:
In this work, we propose a novel convex dual approach to the multidimensional dimensional
assignment problem, which is an NP-hard binary programming problem.
It is shown that the proposed dual approach is equivalent to the Lagrangian relaxation
method in terms of the best value attainable by the two approaches. However,
the pure dual representation is not only more elegant, but also makes the theoretical
analysis of the algorithm more tractable. In fact, we obtain a su cient and necessary
condition for the duality gap to be zero, or equivalently, for the Lagrangian relaxation
approach to  nd the optimal solution to the assignment problem with a guarantee.
Also, we establish a mild and easy-to-check condition, under which the dual problem
is equivalent to the original one. In general cases, the optimal value of the dual
problem can provide a satisfactory lower bound on the optimal value of the original
assignment problem.
We then extend the purely dual formulation to handle the more general multidimensional
assignment problem. The convex dual representation is derived and its
relationship to the Lagrangian relaxation method is investigated once again. Also,
we discuss the condition under which the duality gap is zero. It is also pointed out
that the process of Lagrangian relaxation is essentially equivalent to one of relaxing
the binary constraint condition, thus necessitating the auction search operation to
recover the binary constraint. Furthermore, a numerical algorithm based on the dual
formulation along with a local search strategy is presented.
Finally, the newly proposed algorithm is shown to outperform the Lagrangian
relaxation method in a number of multi-target tracking simulations.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: SEEING BETTER ON THE LEVEL OF LAMPS:  PERCEPTUAL NORMATIVITY IN MERLEAU-PONTY

contributor:
Sassen, Brigitte
Philosophy

subject: Perception Normativity

abstract: This thesis develops an interpretation of Merleau-Ponty’s existential-phenomenological conception of perceptual normativity, that is, how there are norms, internal to perception itself, governing our everyday perceptual involvements with the world. I argue that Merleau-Ponty conceives perceptual norms as being gestalt-structural forms of ‘original sense’, which we experience pre-reflectively in a direct, bodily way. I motivate my interpretation by examining a passage in Phenomenology of Perception where Merleau-Ponty remarks on how perception tends toward an optimal or better view of things, indicating a normative dimension in perception. I make sense of this passage in relation to Merleau-Ponty’s wider gestalt-ontological thought about embodied subjectivity. I unpack how, via the basic intentional structure of perspective by which subject is geared into the perceptual world, body-subject adopts an ‘original sense’ or ‘look’, which undergoes an open process of definition that is experienced as normative. This account can further clarify some questions Merleau-Ponty does not explicitly address about our lived experience of perceptual norms: namely, how perceptual norms are temporal and contingent in their hold on body, and how these norms integrate the subject’s perceptual interests. I further investigate how perceptual norms, in the context of Merleau-Ponty’s thought, are perceived in a two-fold or ambiguous way: the subject lives norms immediately from the ‘inside’, but can also adopt a perspective on norms. In so doing, the subject can perceive the norm itself from the ‘outside,’ which is to partially ‘free’ body from the world’s normative grip. This interpretation is presented as a response to a debate in the literature involving Sean Kelly, Corinne Lajoie, and Samantha Matherne on how Merleau-Ponty conceives perceptual normativity.

abstract: Thesis

abstract: Master of Arts (MA)


title: Investigating the Effects of Glucose and Sweet Taste on Corticospinal and Intracortical Excitability

contributor:
Nelson, Aimee
Kinesiology

subject:
glucose
transcranial magnetic stimulation
blood pressure
corticospinal excitability
intracortical excitability
Primary Motor Cortex

abstract: Transcranial magnetic stimulation (TMS) is commonly used to measure corticospinal and intracortical excitability in basic and clinical neuroscience. However, the effect of glucose on TMS-based measures is not well defined, despite a potentially impactful influence on precision and reliability. Here, a double-blinded placebo-controlled study was used to test the effects of glucose on two commonly used TMS measures: short-interval intracortical inhibition (SICI), and the area under the motor evoked potential recruitment curves (AURC).  SICI and AURC are thought to reflect inhibitory (GABAergic) and excitatory (glutamatergic) neurotransmission respectively. Healthy males (N=18) each participated in four sessions.  Session 1 involved TMS familiarization and acquisition of an individualized blood glucose response curve. During sessions 2, 3 and 4, dependent measures were taken before (T0) and twice after (T1 & T2) drinking 300 mL of solution containing glucose (75 g), sucralose-sweetened placebo (control for sweetness) or plain water (control for time). The T1 and T2 measurements were started 5 minutes prior to the blood glucose peak observed during Session 1. Blood glucose and mean arterial pressure (MAP) were also monitored. Sucralose, but not water or glucose increased AURC and none of the treatments altered SICI. There was no association between blood glucose level and TMS measures, but in all three conditions MAP rose after consumption of the drink. There was a positive correlation between the rise in blood pressure and the relative increase in AURC at the higher stimulus intensities. Eleven participants returned for a fifth session to quantify the smallest detectible change in the AURC measurements and it was confirmed that significant changes were real while non-significant differences in measurement means fell within the range of expected measurement error. This study also suggests a relationship between corticospinal excitability and autonomic tone. Additional investigation is required to understand the mediating factors of this association.

abstract: Thesis

abstract: Master of Science (MSc)


title: On the Origin of Micro-Cracking in Zn-Coated Press Hardened Steels

contributor:
Bassim, Nabil D.
McDermid, Joseph R.
Materials Science and Engineering

abstract:
Zn-coated press hardened steels are in high demand in the automotive industry because their high strength enhances passenger safety while supplying cathodic corrosion protection. However, micro-crack formation after thermomechanical processing is an issue that limits full deployment. One of the most commonly used mechanisms for micro-cracking in Zn-coated press hardened steels (PHS) is liquid metal embrittlement (LME). During hot press forming, LME is induced by the penetration of liquid zinc along the grain boundaries of the substrate which negatively impacts mechanical properties by causing premature failure of the part. The mechanism of LME is well-established; however, it can not be applied to all cases of embrittlement in Zn-coated PHS. Therefore, the objective was to determine a new mechanism for micro-cracking in Zn-coated PHS. The focus was to address the relationship between the origin of micro-cracking and final coating microstructure created by an inward diffusion between the Zn-based overlay and underlying ferrous substrate as a function of annealing time.
Zn-coated 22MnB5 steel sheets were annealed at 900 °C for different annealing times (30 s, 60 s, 120 s, 180 s, 240 s, 300 s, 420 s, 600 s, 780 s), and were then planar or U-shaped die-quenched with an average cooling rate of 100 °Cs-1, resulting in a fully martensitic substrate microstructure. In order to precisely determine the zinc distribution and degree of Zn penetration into the bulk substrate, four sets of samples were examined. The first set of samples were annealed for 30 s (the shortest time) and 780s (the longest time) and die-quenched while the second set comprised tensile specimens from the 30 s and 780 s annealing times which were subsequently pulled to failure. The third and fourth set of samples were selected from two areas (top surface and outer
wall surface) on the U-shaped die-quenched samples that were annealed for 30 s and 780 s. U-shaped die-quenched DHPF allowed for the production of in-situ micro-cracks during forming rather and the ex-situ cracks formed during tensile testing of the planar die quench samples. The PAGBs of the substrate and GBs of the α-Fe(Zn) coating were studied before tensile testing to observe how zinc diffusion in these regions can contribute to later micro-crack formation. The micro-crack tips were investigated after tensile testing and micro-crack formation.
Scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) results showed that, by increasing annealing time, the zinc concentration in the coating decreased while the coating thickness increased parabolically. The coating microstructure underwent a transformation from a dual phase (Γ-Fe3Zn10 + α-Fe(Zn)) layer to a single-phase layer (α-Fe(Zn)) after annealing for 300s. Electron backscatter diffraction (EBSD) and scanning transmission electron microscopy couples with electron energy loss spectroscopy (STEM-EELS) were performed on four sets of samples. EBSD determined that for a α Fe(Zn) or dual-phase (Γ Fe3Zn10 + α Fe(Zn)) coating layer, a transition layer of Zn-enriched martensite (Zn-’) was present in the as-quenched samples. STEM-EELS results for both ex-situ and in-situ micro-cracking, in the absence or presence of tension, indicated zinc enrichment in the PAGBs, GBs and, at the micro-crack tip in the PAGB region for both the 30 s and 780 s DHPF samples. In addition, EELS semi-quantitative analysis of zinc concentration in the α-Fe(Zn) GBs and in the coincident PAGBs implied the presence of a thin α-Fe(Zn) layer in these regions. Based upon the current results, a new mechanism was proposed for the origin of micro-cracking in Zn-coated 22MnB5 DHPF.

abstract: Thesis

abstract: Master of Materials Science and Engineering (MMatSE)


title: Dynamometer Testing and Characterization of Switched Reluctance Motors (SRMs) for Electrified Powertrains

contributor:
Emadi, Ali
Bilgin, Berker
Electrical and Computer Engineering

subject:
Electric Vehicle
Electric Motor
Switched Reluctance Motor
Electric Powertrain
Dynamometer

abstract: The electric vehicle (EV) market is experiencing growth at an exponential rate, forcing automotive manufactures to invest in powertrain electrification. Manufactures are seeking low cost alternatives for electric propulsion motor technologies with switched reluctance motors (SRMs) having tremendous potential. The performance characteristics of SRMs designed for EV propulsion applications have yet to be experimentally verified. In this thesis, the operation of a 24/16 propulsion SRM specifically designed for a hybrid electric vehicle will be verified with a theoretical model and experimentally. The results are analyzed to gain further understanding of the factors affecting propulsion SRM operation. Two distinct theoretical models of a SRM are presented where one includes the effects of mutual coupling between two excited phases. The theoretical models and the experimental results indicate that for high power density SRMs, designed for propulsion applications, the effects of mutual coupling cannot be ignored. The motor is experimentally tested using a dynamometer machine. A test plan is presented which tests the motor at a wide speed and torque range suitable for EV applications. The testing procedure attempts to segregate the motor losses similar to international standards for induction machines and permanent magnet machines; however, these methods prove invalid due to the non-sinusoidal current in SRMs. Torque ripple minimization is highlighted to reduce the risk of detrimental speed fluctuation during motor testing with careful attention to thermal limitations. The SRM is tested using PWM current control as the baseline control method because hysteresis control is proven to be challenging for the tested SRM. The work presents many challenges associated with the testing and characterization of SRMs for propulsion applications; however, new research findings illustrate the potential of future improvements in propulsion SRM design and operation.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Development of chemiresistive sensor made of carbon nanotube to detect E. coli

contributor:
Puri, Ishwar
Materials Science and Engineering

abstract: Rapid detection of bacteria is crucial to control the increasing number of outbreaks and food recalls. The current detection method relies on a lab based bacterial culture that takes several hours to few days to test the samples. Here, we demonstrate a facile and rapid fabrication of a chemiresistive sensor using multiwalled carbon nanotubes (MWCNTs) for detecting E. coli bacteria. MWCNTs functionalized with magnetic nanoparticles, act as the transduction element and magnetically assisted printing is used to obtain a thin conducting strip. The sensing strip is functionalized with specific antibodies for target bacteria. E. coli K12 is chosen as the target bacteria and Bacillus subtilis as the negative control. Specific binding between antibody and bacteria is investigated by measuring the change in the resistance of the strip. The change in resistance is proportional to the increasing concentration of bacteria present in the sample. A response time of ~ 2 minutes can be attributed to the sensor. The detection limit with whole cell is in the range of 105 cells/ml, whereas with the cell lysates, the limit of detection improves to 103 cells/ml.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Selection History in Attentional Control: Evidence from Contextual Cueing Effect and Item-specific Proportion Congruent Effect

contributor:
Hongjin, Sun
Bruce, Milliken
Psychology

subject: attentioal control

subject: contextual cueing effect

subject: item-specific proportion congruent effect

abstract:
A long-held belief is that human attention can be deployed voluntarily according to observers’ goals (top-down) or shifted automatically to the most salience object in the environment (bottom-up). Recent studies suggest a third category of attentional control: selection history. By this view, an observer’s experience in performing a task that requires the control of attention could automatically affect subsequent attention deployment in the task. This thesis examined selection history mechanisms of attentional control in two visual search phenomena. The first phenomenon is known as the Contextual Cueing Effect (CCE), and refers to an increased search efficiency when a specific distractor configuration is repeatedly associated with a specific target location (Chun and Jiang, 1998). In one study, we found a CCE when one repeated configuration was associated with up to four different target locations, suggesting that the CCE may involve mechanisms other than attentional guidance by one-to-one context-target associations. In another study, we found that the CCE was not affected by concurrent working memory load, and that there was little correlation between the magnitude of the CCE and working memory task performance when measured separately in the same participants. These results suggest that working memory may not be involved in such contextual learning. The second phenomenon is
known as the the Item-Specific Proportion Congruent (ISPC) Effect, and refers to item-specific learning that controls the extent to which salient distractors capture attention. Through manual response and eye movement measures, we demonstrate that the ISPC effect reflects the search process itself, rather than processes that precede or follow search. We propose does item-specific learning produces transient changes in the activation of goal-related processes that mediate attention capture.

abstract: Thesis

abstract: Doctor of Psychology (PsyD)

abstract: Where we attend in visual space can be affected involuntarily by memories of how we have attended to visual space in the past. In other words, automatically retrieved memories can control our visual attention independent of volition. This thesis examines two visual search phenomena that display this type of memory-based control over attention. The first phenomenon reveals that search performance improves with experience searching through the same set of visual distractors on multiple occasions. We demonstrate that this form of learning is remarkably flexible; it can occur for multiple targets associated with the same set of distractors. We also demonstrate that this form of learning probably involves long-term rather than short-term memory mechanisms. The second phenomenon reveals how memory-based processes can prevent attention from being captured by a salient distractor. Eye movement data reveal that this form of learning impacts search itself, rather the processes that precede or follow search.


title: Examining the Association of Physical Activity and Mindfulness with Acute Stress and Mental Health

subject:
physical activity
mindfulness
mental health
stress reactivity

abstract: Stress is one of life’s greatest health threats and increases susceptibility to mental illness. Physical activity and mindfulness are lifestyle factors that are protective against mental health concerns. Critically, those with high levels of physical activity also tend to have high levels of trait mindfulness—the tendency to be more mindful in everyday life. However, the relationship between physical activity and mindfulness, and their impact on acute stress and mental health, remains unclear. The current study aimed to explore this association between physical activity and mindfulness, and their relative impact on acute stress reactivity and mental health. Specifically, we examined whether trait mindfulness accounted for unique variance after controlling for physical activity. In a sample of young adult participants (N = 50) we first assessed their physical activity, trait mindfulness, and mental health and then exposed them to the Trier Social Stress Test, during which we recorded using heart rate, blood pressure, salivary cortisol samples, and state anxiety. Hierarchical linear regression revealed a distinct pattern, such that physical activity was more strongly associated with acute stress (heart rate and state anxiety reactivity), whereas trait mindfulness was more strongly associated with mental health even after controlling for physical activity. The results suggest that physical activity and trait mindfulness may work via synergistic mechanisms to enhance wellbeing with physical activity reducing stress reactivity and trait mindfulness improving overall mental health.

abstract: Thesis

abstract: Master of Science in Kinesiology


title: Genetic variation of Aspergillus fumigatus from Auckland, New Zealand

title: Contemporary gene flow is a major force shaping the Aspergillus fumigatus population in Auckland, New Zealand

contributor:
Xu, Jianping
Biology

subject:
Aspergillus fumigatus
Global population structure
Microsatellite Genotyping
Gene Flow
Triazole resistance

abstract: Aspergillus fumigatus is a globally present opportunistic fungal pathogen that plays a key role in degrading organic matter. A. fumigatus can cause a vast array of diseases, collectively known as aspergilloses. The most serious of these is invasive aspergillosis, that has a mortality rate of 30 to 95% with treatment. Recent studies have indicated that the global A. fumigatus population consists of multiple divergent genetic clusters that are broadly distributed geographically. However, most of the previously analyzed samples have come from continental Eurasia and the Americas where the effects of historical or contemporary gene flow is difficult to distinguish. My thesis project, therefore, focused on analyzing the genetic diversity of the Auckland, New Zealand A. fumigatus population, as it is geographic distant from all previously analyzed populations. Here, we obtained 104 A. fumigatus isolates from Auckland and compared the genotypes of these isolates to population data obtained from nine other countries from Europe, Africa, North America, and Asia. The goal was to analyze the potential effects of historical differentiation and gene flow within this population. We determined that the Auckland population had a low, non-significant level of differentiation compared to most previously surveyed global populations. However, the Auckland population also contained unique genetic elements not present within populations from other geographic regions. Though the hypothesis of random recombination was rejected, we found abundant evidence for phylogenetic incompatibility and recombination within the Auckland A. fumigatus population.  Lastly, we identified two triazole resistant strains within the Auckland population, with one carrying the common TR34/L98H cyp51A mutation. Our results suggest that contemporary gene flow, likely due to anthropogenic factors, is a major force shaping the New Zealand A. fumigatus population. These results contribute to our understanding of the high levels of gene flow observed within and among many geographic populations of A. fumigatus.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Aspergillus fumigatus is a globally distributed fungal mold capable of causing serious diseases in individuals with weakened immune systems or lung damage. In the environment, A. fumigatus lives in the soil where it degrades organic matter and contributes to the cycling of nitrogen and carbon across the planet. Due to the airborne nature of its spores, people inhale this fungus daily, and those at risk may develop disease. These diseases, collectively known as aspergilloses, can result in long term chronic illnesses, and in the case of invasive aspergillosis, the death rate can be as high as 95%, even with treatment. Medical treatment of aspergilloses involves the use of antifungal drugs. However, some A. fumigatus strains have developed resistance. I am interested in the patterns of global genetic diversity of A. fumigatus populations. For my MSc thesis, I investigated the A. fumigatus population within Auckland, New Zealand, as it is both geographically isolated and distant from other previously surveyed populations. Our data illustrated that the New Zealand population contains pockets of unique diversity as well as high levels of similarity to the previously surveyed populations within Europe. My results suggest that human influences, likely due to travel and trade, have played a large role in shaping the genetic diversity of the A. fumigatus population from Auckland, New Zealand.


title: Imagery is like perception: three perceptual effects produced with color imagery

contributor:
Milliken, Bruce
Psychology

abstract: Investigations of visual imagery are as old as documented scientific inquiry. Despite this, there is still little understanding of how visual imagery interfaces with our perceptual world. In the present thesis, I investigated three perceptual effects to evaluate whether they were influenced by color imagery. The first effect is an inter-trial priming effect known as the Priming of Pop-out (PoP) effect that constitutes faster responding when the target and distractor colors are repeated than when they are switched across trials of visual search. Here, it was demonstrated that when color imagery was put in opposition with the color of previous target, a pattern of results emerged that was opposite that of the PoP effect – suggesting that color imagery interacted with the representations typically driving the PoP effect. The second effect were those associated with stimulus-response (S-R) bindings, often termed event file binding effects. In a typical event file procedure, it is demonstrated that performance is efficient when an arbitrary key-press is made in response to color stimuli that either completely match or mismatch the S-R bindings of a following two-alternative force choice (2AFC) task, and inefficient when there is partial overlap between these S-R bindings. We demonstrated that color imagery bound to arbitrary responses could produce quite similar effects on a 2AFC color discrimination task as those produced by perceptual colored stimuli. The last effects were the facilitation and inhibition effects observed across trials of 2AFC tasks when targets are presented in the same location. Here it was demonstrated that both perceptual and imagined colored targets led to fast responding when they matched perceptual color targets on the following trial than when they mismatched. When an irrelevant task intervened between these targets, the opposite pattern of results was observed; responses were slower when either the imagined or perceptual targets matched than when they mismatched. This suggests that color imagery could produce priming or habituation-like effects much like perceptual colors. Overall, the present thesis supports the idea that color imagery can influence many of the processes guiding our behavior in the perceptual world.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Effects of Exercise on Cognition Post-Stroke: Are There Sex Differences?

contributor:
Tang, Ada
Rehabilitation Science

subject:
Stroke
Cognition
Exercise
Sex and Gender

abstract: Evidence in older adults suggest that the benefits of exercise on cognition may be moderated by sex. To our knowledge, no studies have examined this relationship in individuals with stroke. This thesis investigated whether there were sex differences in the effect of exercise on cognition post-stroke. The first study was a systematic review of the literature on exercise and cognition in individuals with stroke. The second study was a secondary analysis of data from a randomized controlled trial comparing the effect of aerobic vs. balance and flexibility exercise on cognition. Findings from the systematic review revealed no differences between studies of higher and lower female proportions with respect to memory (Verbal Digit Span Forward, Memory Domain of Stroke Impact Scale and Wechsler Memory Scale III - Verbal Pairing Domain: Chi2 =1.52, p=0.22), executive function (Stroop Test: Chi2 = 0.56, p=0.45; Trail Making Test B: Chi2 = 0.00, p=0.98), language (Communication Domain of Stroke Impact Scale: Chi2 = 3.17, p=0.08) or global cognition (Montreal Cognitive Assessment, Cognitive Domain of Functional Independence Measure and Addenbrooke’s Cognitive Examination-Revised: Chi2 = 0.88, p=0.35). Findings from the secondary analysis indicated that there was a group x time interaction in females (effect size 0.28, p=0.03) that was not observed in males (effect size 0.01, p=0.62). Females demonstrated a Stroop Colour-Word Interference test change of -2.3 seconds, whereas males demonstrated a change of +5.5 seconds following AE. There were no differences between exercise groups in either sex for any of the other outcomes (working memory and set-shifting/ cognitive flexibility). Together, these studies suggest that there is a clear need for future clinical trials that incorporate sex-based analysis to adequately investigate sex-dependent effects of interventions.

abstract: Thesis

abstract: Master of Science Rehabilitation Science (MSc)


title: The roles of male persistence and aggression in male-male and male-female interactions in Drosophila melanogaster

title: Persistence and aggression in Drosophila melanogaster

contributor:
Dukas, Reuven
Psychology

subject:
Aggression
Persistence
Drosophila
Fruit flies
Resource defence
Forced copulation

abstract: All animals face a complex environment full of obstacles that they must overcome in order to survive and reproduce. How an individual responds to its environment is essential to overcoming such obstacles in order to maximize fitness. In my thesis, I focused on the roles of persistence and aggression in achieving fitness-relevant goals. Persistence is continuing in a course of action in spite of difficulty or resistance, and aggression is any instance where an individual uses physical, and potentially damaging, force against a conspecific. I used fruit flies (Drosophila melanogaster) as a model system to examine the ways in which males use persistence and aggression to attain fitness-relevant goals such as defending resources, gaining access to females, and mating. I first examined how a male’s age affected his persistence in courting recently mated females, who are generally unreceptive, and found that older males were more persistent than younger males (Chapter 2). Next, I showed that males of different ages differed in their courtship persistence in the presence of a competitor, and that males were able to subtly, but directly, interfere with one another’s courtship attempts (Chapter 3). I then demonstrated how males were able to use aggression in a mate guarding context to reduce the likelihood that a competitor male mated with their recent mate (Chapter 4), and as a form of resource defense to defend a desirable food patch in the presence of a potential mate (Chapter 5). Finally, I considered male persistence in the pursuit of unreceptive females as a form of male sexual aggression towards recently mated and sexually immature females (Chapters 5 and 6). Overall, my thesis work demonstrates how complex, and sometimes intertwined, the roles of persistence, aggression, and sexual coercion can be even within a ‘simple’ model organism, such as the fruit fly.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: All animals face obstacles from their environment that they must respond to in order to survive and reproduce. In this thesis, I focused on how males use aggressive and persistent behaviours to overcome environmental obstacles. Aggression is the use of physical force against another individual, and persistence is when an individual continues in a course of action despite difficulties. I used fruit flies as a model to examine how males fight with one another over access to food and potential mates. I also studied how males persistently harass females in order to mate with them. In many experiments, I found that males use a combination of aggressive and persistent behaviours to achieve a goal. Overall, my results show that even in a simple species like fruit flies, individuals can use complex combinations of behaviours to achieve a variety of goals.


title: Character Mediation of Plot Structure: Toward an Embodied Model of Narrative

contributor:
Brown, Steven
Psychology

subject:
Plot
Narrative
Problem solving
Embodied
Character
Fairy tale

abstract: The classic view of narrative since the time of Aristotle is that plot structure is prioritized over characters in defining the nature of stories. According to this view, plot is an abstract structure external to the protagonist, and the protagonist’s actions are determined by the thematic goals of the plot. The current analysis calls for a reversal in the prioritization of these elements in creating a story. We present an Embodied Plot model in which character not only drives plot, but embodies plot as well. According to this model, the dramatic arc of plots is attributable to psychological processes occurring in the protagonist’s mind. Plot structure is thus isomorphic with the psychological and problem-solving experience of the protagonist inside the storyworld. We apply this model to a number of fairy tales to demonstrate how the dramatic arc of these stories can be explained in each case by the protagonist’s experientiality.

abstract: Thesis

abstract: Master of Science (MSc)


title: WHEN BODIES BECOME OBJECTS AND OBJECTS COME TO LIFE: SPECIALIZED PROCESSING FOR SOCIAL STIMULI AND THE DEVELOPMENT OF ANIMACY DETECTION

contributor:
Rutherford, M. D.
Psychology

abstract: Humans are social beings. They quickly detect other agents such as people or animals, preferentially attend to them (New, Cosmides, & Tooby, 2007), and process social stimuli differently than non-social objects (Reed, Stone, Bozova, & Tanaka, 2003; Yin, 1969). Three studies focused on the ability to differentiate between social and non-social stimuli and on specialized social processing. Chapter two showed that female bodies are perceptually objectified, leading the visual system to process them as objects. However, this effect can be manipulated by providing high or low sexualizing information about a target. Results indicated that body images paired with high sexualizing information are more likely to be perceptually objectified, regardless of whether they are male or female targets. Chapter three showed that infants, like adults, prioritize attention to social stimuli. We used an adapted change detection paradigm to test whether 11-month-olds would be better able to detect changes to animate or inanimate entities. Results indicated that infants are more likely to notice changes to animate entities. Chapter four reports a test of 4-year-old children’s ability to detect a chasing agent among increasing numbers of distractors. Participants were presented with moving displays of a chasing agent and its target, surrounded by up to 10 distractors. Children were asked to identify the chaser by touching it on the screen. Our results showed that 4-year-old children show a pop-out effect for chasing motion. Reaction time to identify the chaser was independent of how many distractors were added to the display. Overall, our studies suggest that, from infancy onward, humans orient towards social information and process it differently than inanimate objects. Further, the context can significantly impact how stimuli are viewed.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Humans rely on other people for social interaction and cooperation. We allocate attention and gaze to social agents, and our visual system processes social stimuli in qualitatively different ways compared to objects. Across three studies, we examined the ability to differentiate between social and non-social stimuli and specialized social processing. In the first study, we investigated in which contexts bodies are processed by the visual system as objects rather than social stimuli. The more sexualized targets are, the more likely they are to be processed as objects. Our second study showed that infants, like adults, prioritize attention toward humans or animals compared to objects. Eleven-month-olds are more adept at detecting the removal of humans or animals compared to objects from an image of a natural scene. In our final study, we tested 4-year-olds’ ability to detect chasing motion. Children can quickly pick out a chasing agent among random motion.


title: Perceptual Functions of Auditory Neural Oscillation Entrainment

contributor:
Trainor, Laurel
Psychology

subject:
Neural entrainment
Rhythm
Audition
Electroencephalography (EEG)

abstract:
Humans must process fleeting auditory information in real time, such as speech and music. The amplitude modulation of the acoustic waveforms of speech and music is rhythmically organized in time, following, for example, the beats of music or the syllables of speech, and this property enables temporal prediction and proactive perceptual optimization. At the neural level, external rhythmic sensory input entrains internal neural oscillatory activities, including low-frequency (e.g., delta, 1-4 Hz) phase, high-frequency (e.g., beta, 15-25 Hz) power, and their phase-amplitude coupling. These neural entrainment activities represent internal temporal prediction and proactive perceptual optimization. The present thesis investigated two critical but previously unsolved questions. First, do these multiple entrainment mechanisms for tracking auditory rhythm have distinct but coordinated perceptual functions? Second, does regularity in the temporal (when) domain associate with prediction and perception in the orthogonal spectral (what) domain of audition? This thesis addressed these topics by combining electroencephalography (EEG), psychophysics, and statistical modeling approaches. Chapter II shows that beta power entrainment reflects both rhythmic temporal prediction (when events are expected) and violation of spectral information prediction (what events are expected). Chapter III further demonstrates that degree of beta power entrainment prior to a pitch change reflects how well an upcoming pitch change
will be predicted. Chapter IV reveals that rhythmic organization of sensory input proactively facilitates pitch perception. Trial-by-trial behavioural-neural associations suggested that delta phase entrainment reflects temporal expectation, beta power entrainment reflects temporal attention, and their phase-amplitude coupling reflects the alignment of these two perceptual mechanisms and is associated with auditory-motor communication. Together, this thesis advanced our understanding of how neural entrainment mechanisms relate to perceptual functions for tracking auditory events in time, which are essential for perceiving speech and music.

abstract: Thesis

abstract: Doctor of Science  (PhD)

abstract: Perceiving speech and musical sounds in real time is challenging, because they occur in rapid succession and each sound masks the previous one. Rhythmic timing regularities (e.g., musical beats, speech syllable onsets) may greatly aid in overcoming this challenge, because timing regularity enables the brain to make temporal predictions and, thereby, anticipatorily prepare for perceiving upcoming sounds. This thesis investigated the perceptual and neural mechanisms for tracking auditory rhythm and enhancing perception. Perceptually, rhythmic regularity in streams of tones facilitates pitch perception. Neurally, multiple neural oscillatory activities (high-frequency power, low-frequency phase, and their coupling) track auditory inputs, and they are associated with distinct perceptual mechanisms (enhancing sensitivity or decreasing reaction time), and these mechanisms are coordinated to proactively track rhythmic regularity and enhance audition. The findings start the discussion of answering how the human brain is able to process and understand the information in rapid speech and musical streams.


title: Applications of dynamical systems to industrial microbiology

contributor:
Wolkowicz, Gail
Mathematics and Statistics

abstract: The use of microorganisms in industrial processes has become very common. In this thesis, we analyze three models of such systems that have applications in green technology. The first is a simplified model of anaerobic digestion, originally introduced as a qualitative simplification of the anaerobic digestion model no 1 (ADM1). While ADM1 is very complicated, the simplified model is composed of only five ordinary differential equations. We show that this model can be reduced to a two-dimensional system that is equivalent to the basic chemostat model with explicit species death rate and non-monotone response function. We show that this chemostat model has no periodic solutions and completely characterize the possible dynamics of the two dimensional system and then the full five-dimensional system. In the second model, we consider the self-cycling fermentation process with two limiting essential resources with impulses that occur when both resources fall below a prescribed threshold. We show that the successful operation of the self-cycling fermentor is initial-condition dependent and that success is equivalent to the convergence of solutions to a periodic solution. We show numerically that there is an optimal choice for the emptying/refilling fraction and that the optimal choice is not always 1/2, the standard choice in the engineering literature. In the third model, we consider the self-cycling fermentation process with an arbitrary number of nutrients with impulses that occur when one specified nutrient concentration falls below a prescribed threshold. We show that successful operation of the self-cycling fermentor is equivalent to the convergence of solutions to a periodic solution. We derive conditions for the existence of this periodic solution and initial-condition-dependent conditions for convergence to this solution.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Low-cost Bench-Top Microfabrication of Nano/Microstructured Electrodes for Electrochemical Biosensing

contributor:
Moran-Mirabal, Jose
Chemistry

abstract:
The lack of safe drinking water, access to medical treatment and equipment, and sus-tainable energy are some examples of problems affecting the majority of developing nations today, and are collectively responsible for over 15 million annual deaths globally. While tech-nological advances have enabled developed countries to improve the average health quality and overall life expectancy of their populations, the adoption of such technologies is cost-prohibitive for countries with small healthcare budgets. One of the obstacles in achieving low-cost and simple-to-use biotechnologies are versatile and robust fabrication methods. Therefore, there is great demand for novel and feasible biomedical device technologies that can address the current healthcare challenges of resource-limited nations.
In this thesis, a low-cost and rapid bench-top fabrication method is introduced to cre-ate nano/microstructured electrodes (NMSEs) with applications in microfluidic cell sensing, enhanced energy capture, and hemolytic agent detection. Metal deposition and viscoelastic shape-memory polymers were used to rapidly create highly tuneable wrinkled electrodes with electrochemical surface area enhancements of up to 650% and miniaturization down to 16% from the original area. These shrunken metallic electrodes were transferred onto polydime-thylsiloxane (PDMS) using a dissolvable photoresist liftoff technique. The result was a new, all PDMS-based flexible microfluidic cell sensor, capable of detecting 3T3 fibroblast cells down to 2x106 cells/ml and able to withstand flowrates of up to 100 mL/min. In a second project, biofilms of Geobacter sulfurreducens were cultured onto wrinkled NMSEs with enhanced electro-active surface area, which served as bioanodes in a microbial fuel cell. This enhanced microbial fuel cell generated twice the power output of control devices containing planar electrodes in lieu of the larger wrinkled variety. Next, we developed a phospholipid membrane-on-a-chip platform for the electrochemical detection of membrane disrupting agents. We deposited a coating of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) phospholipids on the sur-face of the NMSEs to inhibit charge transfer between the redox reporter molecule in solution and the electrode. Lytic compounds were hypothesized to disrupt the coating, such that the exposed NMSE interface could facilitate the monitoring of the signal transduction from redox
Ph.D. Thesis – Sokunthearath Saem McMaster – Chemistry and Chemical Biology
iv
molecules in solution. A first round of experiments tested the DMPC-coated NMSEs against commercially available sodium dodecyl sulfate (SDS) and Polymyxin-B (PmB), an antibiotic known to cause membrane rupture through dissolution and pore formation. The results indi-cated viable devices with limits of detection at 10 ppm and 1 ppm for SDS and PmB respec-tively. Lastly, we added cholesterol to the DMPC phospholipids to create stable supported membranes on NMSEs. The addition of cholesterol to DMPC increased the supported mem-brane stability against SDS and PmB where pure DMPC membranes produce higher signal recovery than cholesterol rich membranes. As a proof-of-concept, we tested the cholesterol rich membranes against Pneumolysin (PLY), a hemolytic protein known to rupture cell mem-branes. The LOD of SDS, PmB, and PLY was determined to be 500 ppm, 1 ppm, and 600 ppb respectively. All three electroanalytical devices produced using our shape-memory poly-mer structuring technique exemplify the potential of this versatile platform to help address the issues currently facing developing countries.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Seizing the Means of Prediction: Interrogating Populist Technologies in the Emerging Asocial Society

subject: digital cultural studies, psychoanalytic political theory, critical internet studies, post-politics, populist technologies

abstract: By enabling the compilation of ‘big data’ from which knowledge of our patterns of thought, consumption, and action can be drawn, social media platforms give state and non-state actors private access to our political imaginations and thus expose the fault lines within our collective consciousness. This paper investigates how emerging and disruptive populist technologies automate the manufacturing of consent on social media platforms and the impact these technologies are having on our civil discourse and democratic sovereignty. Populist technologies can be understood as the dialectical Other of techno-neoliberalism. Where techno-neoliberalism functions as an assemblage of the political power of the state, the market power of corporations and the scientific know-how of technocrats, we can see populist technologies suturing old hatreds with new technologies. While populist media technologies have been analyzed as software and engineering technologies, they have yet to be considered from a psychoanalytic political theory perspective. The socio-cultural effects of the changing nature of digital propaganda are only just beginning to be understood, and the advancement of this understanding is complicated by the unprecedented union of the social and the technical that the internet has enabled, and which has subsequently resulted in the erosion of democratic practices. Given the competing needs of security and privacy in an increasingly datafied asocial society, the need to understand how big data analytics shape contemporary electoral dynamics has taken on a new level of urgency. Using the lens of psychoanalytic political theory, this paper engages in a critical analysis of the implications of emergent digital technologies for public discourse and political practice in the age of (a)social media.


title: Landau Theory of Complex Ordered Phases

contributor:
Shi, An-Chang
Physics and Astronomy

subject:
Landau theory
Soft matter

abstract: Recently, a number of spherical packing phases belonging to the class of Frank-Kasper (F-K) phases have been observed in a wide range of soft matter systems, including block copolymers, ionic surfactants, liquid crystalline dendrimers, and giant surfactants. Although their emergence in such systems has been conjectured to be due to a competition between mesodomain sphericity and incompressibility, we lack a description of a precise and general mechanism underlying the formation of F-K phases in soft matter systems. In this work, we consider the two most common F-K phases found in soft matter systems, the σ and A15 phases, and study their stability in the context of a well-known Landau model known as the Landau-Brazovskii model. This model has been applied to systems ranging from block copolymers to liquid crystals. We find that the phase behavior of the Landau-Brazovskii model is controlled only by two parameters, rather than by three parameters, as was suggested by previous works. We also find that the Landau-Brazovksii phase diagram contains regions in which the σ or A15 phase is the most stable among a set of candidate phases. The fact that such a simple model can predict these complex phases provides some insight into the question of why the occurrence of the Frank-Kasper phases in soft matter is so widespread.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Soft condensed matter physics studies the properties of materials that easily deform, such as soap, gel and plastic. Many of these materials can self-assemble into various fascinating ordered structures. One particularly complex class of structures, found in a wide range of soft materials, is the class of Frank-Kasper phases. Frank-Kasper phases in soft materials have potential applications in fields such as photonics, so their formation in these materials is particularly interesting. However, it is not well understood why the Frank-Kasper structures occur in so many soft materials. We investigate this problem, and show that the occurrence of these structures might be described by a very simple mathematical model known as the Landau-Brazovskii model. The fact that such a simple model can predict the complex Frank-Kasper phases provides insight into the origin of the widespread nature of the occurrence of Frank-Kasper phases in soft materials.


title: The upper respiratory tract microbiota contributes to susceptibility to Streptococcus pneumoniae infections

title: Characterizing the murine nasal microbiome

contributor:
Surette, Michael
Biochemistry and Biomedical Sciences

subject:
microbiome
microbiota
mouse
Streptococcus pneumoniae
Actinomyces
sialidase

abstract: The upper respiratory tract (URT), including the nasal and oral cavities, is a reservoir for pathogenic and commensal microbial species, collectively known as the microbiota. Microbial colonization of the URT occurs right after birth, and URT microbial composition has been linked to development of respiratory infections, allergy, and asthma, though few direct mechanisms have been uncovered. Thus, I set out to establish animal models for characterizing the URT microbiota, and its role in infections. I found that nasal washes, a predominant method for measuring URT bacterial colonization, were insufficient for completely extracting the URT microbiota. The age and source of mice greatly affected the composition of the microbiota, which could be transferred to germ-free mice via cohousing. I also established that mice colonized with the Altered Schaedler’s Flora in the gut microbiota have no cultivable URT microbiota. To test the function of the URT microbiota, I colonized mice with Streptococcus pneumoniae, the leading cause of bacterial pneumonia worldwide. I show that the presence of a nasal microbiota increases permissiveness to pneumococcal infection in murine models. Addition of a single URT isolate, Actinomyces naeslundii, increased pneumococcal adherence to human respiratory epithelial cells in vitro and increased pneumococcal dissemination in vivo in a sialidase-dependent manner. The microbiota affects expression of several host genes throughout the respiratory tract involved in pneumococcal pathogenesis. Together, this work establishes new models for assessing the URT microbiota, and highlights the contribution of the URT microbiota to pneumococcal pathogenesis and identifies druggable targets to prevent and treat infections.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Bacteria living in the gut have been shown to benefit our health, but the role of bacteria living in our respiratory tract is relatively unknown. I describe the methods for characterizing the bacteria in the nose of a mouse as a model of the human nose. I found that pockets of the mouse nose are colonized by different bacteria. I also characterized a mouse model that had bacteria in the gut without nasal bacteria. I used this mouse model to understand infections with Streptococcus pneumoniae, the worldwide leading cause of bacterial pneumonia. The mice without nasal bacteria were protected from infections, which was due to a nasal bacteria helping S. pneumoniae escape from the nasal tissue. This work established new models for understanding how bacteria affect respiratory health, and identified new targets for protecting against infections.


title: Reassessing the Genres of the Hodayot (Thanksgiving Psalms from Qumran)

title: Reassessing the Genres of the Hodayot

contributor:
Schuller, Eileen
Religious Sciences

subject:
Dead Sea Scrolls
Genre
Qumran
Hodayot
Thanksgiving Psalms

abstract:
The psalms of the Hodayot tradition (the Thanksgiving Psalms from Qumran) have been customarily divided into two categories: the “Teacher Hymns” written by a leader of the sect at Qumran, and the “Community Hymns” associated with the ordinary members of the sect. These categories are considered problematic because of well-recognized problems pertaining to authorship and to the poor fit of many of the psalms in the categories. I propose a new set of categories for the Hodayot that classify the psalms on the basis of genre. It is my contention that genre offers a better frame of reference because it defines the psalms against the backdrop of the genres of early Jewish psalms and not solely in terms of the sectarian community.

To propose new generic categories, I employ John Swales’s rhetorical moves analysis to classify the psalms on the basis of how their formal structures (what he calls “rhetorical moves”) work together to achieve common rhetorical objectives. Swales defines a composition’s genre primarily by its rhetorical objectives rather than a definitional checklist of features. I use rhetorical moves analysis to describe where the Hodayot psalms fall along the spectrum of descriptive and declarative praise in Claus Westermann’s schema for the genres of the biblical psalms. I conclude that there are two interlocking generic categories in the Hodayot: eschatological psalms of thanksgiving and psalms of hymnic confession. These generic categories have overlapping rhetorical strategies consisting of rhetorical moves that work closely together to achieve the primary communicative purpose of praising God descriptively and declaratively. In this respect, they serve the Maskil’s secondary rhetorical objective of instructing the audience in the sectarian discourses of praise and supplication, making the Hodayot tradition a part of the Maskil’s programme of instructing sectarians and evaluating their insight into the divine plan.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: In this thesis I study the Thanksgiving Psalms from Qumran (1QHodayot a ), a collection of Jewish psalms from the Dead Sea Scrolls. The collection is typically divided into two categories: the “Teacher Hymns” written by a leader of a sect, and the “Community Hymns” that are associated with his followers. Scholars agree that these categories are inadequate, but no alternatives have been offered. I propose to use a more flexible approach that can classify all of the psalms by genre. The psalms are classified on a spectrum between two modes of praise by their objectives and strategies of persuasion. I argue that the psalms participate in two interlocking genres (the eschatological psalms of thanksgiving and the psalms of hymnic confession) and that all the psalms enable the speaker (the Maskil/Instructor) to achieve the two objectives of praising God and instructing his audience how to do the same.


title: Group Differences in the Processing of Emotion-Laden Linguistic Stimuli

contributor:
Kuperman, Victor
Shore, David
Humanities

subject: emotion, language, linguistics, psychology

abstract:
This thesis investigated how different groups of people process the emotionality of linguistic stimuli. Recently, individual and group differences have become topics of interest in psychology, but very few studies have investigated how behavioural responses to emotional stimuli vary as a function of participant demographics.
The first study focused on the contrast between how native and non-native speakers of English process the emotional content of English words. The study of emotional processing in non-native speakers is a highly contested issue in the field of bilingualism and experimental psychology. Chapter 2 reports the largest collection of emotion ratings of English words from non-native speakers and provides a theoretical perspective on how bilingual speakers process emotion.
In order to facilitate the investigation of individual differences in emotional processing, the field needs a reliable method that allows for the measurement of subtle differences between individuals. In Chapter 3, I demonstrate that a novel ‘slider’ method of measuring valence, proposed by Warriner et al. (2018), is a reliable tool for measuring affective responses to words along a fine-grained sliding scale.
In Chapter 4, I demonstrate the use of the sliding scale with the aim of capturing affective differences between those with and without depressive symptoms. This chapter reports that compared to those without depressive symptoms, those with depressive symptoms i) exhibit attenuated responses to emotionally laden stimuli, and ii) are unable to take on the perspective of someone without depression.
Overall, this thesis reports on the emotional responses in two hotly debated groups, as well as providing a new method of measuring emotional responses to linguistic stimuli. These findings underscore the importance of studying emotional processing beyond normative populations.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Probabilistic Flood Forecast Using Bayesian Methods

contributor:
Coulibaly, Paulin
Civil Engineering

subject:
Probabilistic flood forecast
Bayesian theorem
Uncertainty quantification
Predictive distribution
Ensemble forecast
Post-processing

abstract:
The number of flood events and the estimated costs of floods have increased dramatically over the past few decades. To reduce the negative impacts of flooding, reliable flood forecasting is essential for early warning and decision making. Although various flood forecasting models and techniques have been developed, the assessment and reduction of uncertainties associated with the forecast remain a challenging task. Therefore, this thesis focuses on the investigation of Bayesian methods for producing probabilistic flood forecasts to accurately quantify predictive uncertainty and enhance the forecast performance and reliability.
In the thesis, hydrologic uncertainty was quantified by a Bayesian post-processor - Hydrologic Uncertainty Processor (HUP), and the predictability of HUP with different hydrologic models under different flow conditions were investigated. Followed by an extension of HUP into an ensemble prediction framework, which constitutes the Bayesian Ensemble Uncertainty Processor (BEUP). Then the BEUP with bias-corrected ensemble weather inputs was tested to improve predictive performance. In addition, the effects of input and model type on BEUP were investigated through different combinations of BEUP with deterministic/ensemble weather predictions and lumped/semi-distributed hydrologic models.
Results indicate that Bayesian method is robust for probabilistic flood forecasting with uncertainty assessment. HUP is able to improve the deterministic forecast from the hydrologic model and produces more accurate probabilistic forecast. Under high flow condition, a better performing hydrologic model yields better probabilistic forecast after applying HUP. BEUP can significantly improve the accuracy and reliability of short-range flood forecasts, but the improvement becomes less obvious as lead time increases. The best results for short-range forecasts are obtained by applying both bias correction and BEUP. Results also show that bias correcting each ensemble member of weather inputs generates better flood forecast than only bias correcting the ensemble mean. The improvement on BEUP brought by the hydrologic model type is more significant than the input data type. BEUP with semi-distributed model is recommended for short-range flood forecasts.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Flood is one of the top weather related hazards and causes serious property damage and loss of lives every year worldwide. If the timing and magnitude of the flood event could be accurately predicted in advance, it will allow time to get well prepared, and thus reduce its negative impacts. This research focuses on improving flood forecasts through advanced Bayesian techniques. The main objectives are: (1) enhancing reliability and accuracy of flood forecasting system; and (2) improving the assessment of predictive uncertainty associated with the flood forecasts. The key contributions include: (1) application of Bayesian forecasting methods in a semi-urban watershed to advance the predictive uncertainty quantification; and (2) investigation of the Bayesian forecasting methods with different inputs and models and combining bias correction technique to further improve the forecast performance. It is expected that the findings from this research will benefit flood impact mitigation, watershed management and water resources planning.


title: Conquering The Demons Within: How Men In Recovery Conceptualize Challenges And Use Their Inherent Strengths To Navigate Them

title: Conquering The Demons Within: Men In Recovery

contributor:
Jackson, Randy
Social Work

subject: Recovery, Addiction, Resilience, Perseverance, Substance Use Disorder, Substance Use, Challenges, Strengths, Obstacles, Strength-based Perspective, Men in Recovery, Drug Addiction, Alcohol Addiction, Scoping Review

abstract:
The aim of this thesis is to explore how men in recovery from substance use conceptualize challenges and use their inherent strengths to navigate them. Estimates of substance use prevalence rates in Canada suggest that approximately one-in-five Canadians will meet the diagnostic criteria for substance use disorder throughout their lifetime (Pearson, Janz & Ali, 2013). These prevalence estimates represent a significant cause for concern as addiction is a significant phenomenon in contemporary Canadian society.
A scoping literature review was conducted on nineteen research studies to investigate the state of current research. Although there is a wealth of studies on addiction, research frequently utilizes pathologizing approaches. These approaches are commonly focused on addiction in the context of a social or individual issue ripe with problematizing discourses. Six qualitative semi-structured interviews were conducted on men living in recovery-based supportive housing for this research to explore their experiences from the onset of substance use into substance use and recovery efforts. A strength-based perspective was adopted for analysis purposes in order to more accurately reflect on the inherent strengths of the participants. The men provided in-depth accounts of their experiences, conceptualized challenges to their recovery and contrary to many contemporary research discourses, demonstrated an affluence of strengths while articulating challenge navigation. The men were also proactive in their ability to anticipate future challenges and conceive methods of effective challenge navigation.
Findings of this study are analyzed and discussed in the context of recognizing the magnitude of the challenges facing the men in recovery and the incredible strengths that they demonstrate in challenge navigation. The implications for current social work practice are outlined and several suggestions are tabled with the goal of improving current practice methods. Finally, suggestions for future strength-based addiction research are offered with the intention of seeking overall improvements to the research field and addressing existing gaps within the literature.

abstract: Thesis

abstract: Master of Social Work (MSW)