title: NANOPARTICLE FLOTATION COLLECTORS

contributor:
Pelton, Robert H.
Shiping Zhu, Michael A. Brook
Chemical Engineering

subject:
Flotation
Nanoparticle Collector
Contact Angle
Hydrophobicity
Micromechanics
Pull-off Force
Coverage
Pentlandite
Recovery
Selectivity
Other Chemical Engineering
Other Chemical Engineering

abstract:
Flotation is a critical operation in the isolation of valuable minerals from natural ore. Before flotation, chemical collectors are routinely added to ground ore slurries. Collectors selectively bind to mineral-rich particles, increasing their hydrophobicity thus promoting selective flotation. Conventional collectors are small surfactants with a short hydrocarbon tail (2-6 carbons) and a head group, such as xanthate. In this work, much larger hydrophobic polystyrene nanoparticles are evaluated as potential flotation collectors. Experiments involving both clean model mineral suspensions and complex ultramafic nickel ores confirm that conventional water-soluble molecular collectors could be partially or completely replaced by colloidal hydrophobic nanoparticle flotation collectors.

The ability of nanoparticles to induce flotation has been demonstrated by floating hydrophilic, negatively charged glass beads with cationic polystyrene nanoparticle collectors. Mechanisms and key parameters such as nanoparticle hydrophobicity and nanoparticle adsorption density have been identified. Electrostatic attraction promotes the spontaneous deposition of the nanoparticles on the glass surfaces raising the effective contact angle to facilitate the adhesion of beads to air bubbles. The pull-off force required to detach a glass sphere from the air/water interface of a bubble into the water was measured by micromechanics. Coating with nanoparticles allows the beads to attach remarkably firmly on the air bubble. As little as 10% coverage of the bead surfaces with the most effective nanoparticles could promote high flotation efficiencies, whereas conventional molecular collector requires 25% or higher coverage for a good recovery. Contact angle measurements of modified glass surfaces with a series of nanoparticles that covered a range of surface energies were used to correlate the nanoparticle surface properties with their ability to promote flotation of glass beads. Factors influencing nanoparticle deposition on glass, such as nanoparticle dosage, nanoparticle size, conditioning time have been investigated with a quartz crystal microbalance (QCM). Deposition kinetics has been analyzed according to Langmuir kinetics model.

Surface functionalized nanoparticles enhance the ability of nanoparticle collectors to selectively deposit onto surfaces of the desired mineral particles in the presence of gangue materials. Poly (styrene-co-vinylimidazole) based nanoparticle collectors have been developed to selectively deposit onto nickel mineral (pentlandite) in the presence of Mg/Si slime. Flotation tests of ultramafic nickel ores with these nanoparticle collectors have shown improvements in both pentlandite recovery and selectivity.

abstract: Doctor of Philosophy (PhD)


title: Self-organizing Dynamic Spectrum Management: Novel Scheme for Cognitive Radio Networks.

contributor:
Haykin, Simon
Electrical and Computer Engineering

subject:
cognitive radio
dynamic spectrum management
wireless ad hoc networks
self-organizing network
wireless communications
Systems and Communications
Systems and Communications

abstract: A cognitive radio network is a multi-user system, in which different radio units compete for limited resources in an opportunistic manner, interacting with each other for access to the available resources. The fact that both users and spectrum holes (i.e., under-utilized spectrum sub-bands) can come and go in a stochastic manner, makes a cognitive radio network a highly non- stationary, dynamic and challenging wireless environment. Finding robust decentralized resource-allocation algorithms, which are capable of achieving reasonably good solutions fast enough in order to guarantee an acceptable level of performance, is crucial in such an environment. In this thesis, a novel dynamic spectrum management (DSM) scheme for cognitive radio networks, termed the self-organizing dynamic spectrum management (SO-DSM), is described and its practical validity is demonstrated using computer simulations. In this scheme, CRs try to exploit the primary networks’ unused bands and establish link with neighbouring CRs using those bands. Inspired by human brain, the CRs extract and memorize primary network’s and other CRs’ activity patterns and create temporal channel assignments on sub-bands with no recent primary user activities using self-organizing maps (SOM) technique. The proposed scheme is decentralized and employs a simple learning rule with low complexity and minimal memory requirements. A software testbed was developed to simulate and study the proposed scheme. This testbed is capable of simulating CR network alongside of a cellular legacy network. In addition to SO-DSM, two other DSM schemes, namely centralized DSM and no-learning decentralized DSM, can be used for CR networks in this software testbed. The software testbed was deployed on parallel high capacity computing clusters from Sharcnet to perform large scale simulations of CR network. The simulation results show, comparing to centralized DSM and minority game DSM (MG-DSM), the SO-DSM decreases the probability of collision with primary users and also probability of CR link interruption significantly with a moderate decrease in CR network spectrum utilization.

abstract: Doctor of Philosophy (PhD)


title: Language Effects in Assessment of Class Inclusion Ability

contributor:
Siegel, Linda S.
Psychology

subject: Psychology Psychology

abstract:
Classification, the recognition, construction, and ordering of classes, is a basic part of thought process. One aspect of classification, class inclusion, requires the quantitative comparison of a superordinate class and its included subclass. According to Piagetian theory, class inclusion is the definitive test of classification competence because inclusion ability demonstrates understanding of the relationships between different hierarchical levels of classes.

Consideration of the relationship of language and thought leads to critical examination of the role of language in assessment of classification skills. To the extent that classification ability precedes or is independent of language development, procedures which rely on linguistic comprehension and production will yield results which are incomplete and possibly invalid. If we vary language in assessment, we should obtain a better understanding of early classification strategies and ability.

This research on class inclusion treats language as an independent variable in two days, by examining alternate verbal forms of the inclusion question, and by reducing language in that question. Within the Piagetian research tradition there is only one classification study with reduced language, and there is one recent experiment which compared an alternate verbal form to the standard Piagetian question for class inclusion. Several experiments are reported here which examined the effects of language variation on class inclusion performance.

In the first alternate form of the inclusion question the word "all" modified the superordinate class, and children gave more correct answers in this case than with the standard unmodified question. Further examination indicated that children performed better with the "all" question because they understood that question better than the standard question.

With the second alternate inclusion form, Siegal's question, children were asked whether they wanted the superordinate class or the subclass. This was an attempt to replicate a previously reported finding that young children gave more correct answers to this form than to the Piagetian question. In the work reported here, after the children answered they were told to take their choice, and when analysis included both this behavioural measure and verbal responses, there were no differences in performance on the standard versions of Siegel's and Piaget's questions. This discrepancey with the earlier finding is discussed in terms of methodological differences between the studies. In contrast to the standard version results, when the word "all" was used in both questions the performance differences obtained were consistent with the previous finding: younger children gave more correct answers to Siegel's than to Piaget's question.

Language in the inclusion question was reduced by using visual symbols to identify the subclasses and the superordinate class. Four-year-olds gave more correct answers to the reduced language question than they did to the standard question in which words identify the classes.

A mathematical model is presented which estimates underlying components of correct and error response to the inclusion question, allowing anlaysis of the strategies that children use with different forms of the inclusion question. For example, the four-year-olds did not do better with the reduced language question because they were demonstrating more inclusion logic with that form. The difference in results was based on use of different non-inclusion strategies: with the reduced language question the children were more likely to guess, and with the standard question they were more likely to compare the subclasses to each other. Use of the mathematical model was critical in preventing false interpretation of the results.

The methodological and analytic implications for class inclusion research are discussed. In general, these studies demonstrate the usefulness of alternate approaches to inquiry, analysis, and interpretation of the existing data concerning the development of thought processes.

abstract: Doctor of Philosophy (PhD)


title: The Regulation of Brain Serotonergic and Dopaminergic Neurons: The Modulatory Effects of Selective Serotonin Reuptake Inhibitors, Atypical Neuroleptics and Environmental Enrichment

contributor: Medical Sciences (Neuroscience and Behavioral Science)

subject:
serotonin
dopamine
tryptophan hydroxylase
tyrosine hydroxylase
selective serotonin reuptake inhibitors
environmental enrichment
Molecular and Cellular Neuroscience
Molecular and Cellular Neuroscience

abstract:
The brain serotonergic and dopaminergic systems broadly influence our internal experience and the ways in which we interact with the outside environment, with crucial regulatory roles in mood, sleep, appetite and the control of voluntary movement. Serotonin and dopamine neurons are themselves influenced by a wide variety of internal and external factors, many of which remain poorly understood. The central aim of this thesis was to better characterize several of these modulatory influences via exploratory investigations involving pharmaceutical agents or environmental modification. Specifically, I examined the modulatory effects of selective serotonin reuptake inhibitors (SSRIs), atypical neuroleptics and environmental enrichment with exercise on the regulation of brain serotonin and dopamine neurons.

This thesis documents, for the first time, that (1) inhibition of the serotonin transporter (SERT) by SSRIs induces a rapid and region-selective reduction of tryptophan hydroxylase (TPH)-immunoreactive neurons in serotonergic brainstem nuclei that persists over a prolonged treatment course; that (2) selective blockade of SERT by SSRIs can rapidly induce a reduction of tyrosine hydroxylase (TH)-positive dopaminergic neurons in the substantia nigra (SN) and the ventral tegmental area (VTA) that, again, persists over a lengthy treatment course; that (3) environmental enrichment with exercise can potentiate the effect of SERT inhibition on SN dopaminergic neurons, but not the dorsal raphe nucleus (DRN) serotonergic neurons; that (4) that SSRI fluoxetine triggers a significant upregulation of microglia in the SN; that (5) environmental enrichment with exercise can reduce TPH immunoreactivity in the DRN and TH immunoreactivity in the SN and VTA, even in the absence of any pharmacological intervention, and finally, that (6) the atypical neuroleptic risperidone significantly reduces TPH in the DRN of both young and aged animals and reduces DRN Nissl counts in aged animals. Taken together, the body of work included in this thesis suggests that SSRIs, atypical neuroleptics and environmental enrichment with exercise can have profound effects on brain serotonergic and dopaminergic neurons, possibly accounting for some of the side effects and therapeutic benefits associated with these interventions.

abstract: Doctor of Philosophy (PhD)


title: STUDY OF REACTIONS BETWEEN HIGHLY FUNCTIONALIZED LOW MOLECULAR WEIGHT POLYETHYLENE AND POLYAMINES TO PRODUCE THERMOSET MATERIALS

contributor:
Potter, David K.
Chemical Engineering

subject: Polyolefin thermosets; functional polyolefins; amine-anhydride reactions; FTIR

subject: Polymer Science

subject: Polymer Science

abstract:
Low molecular weight functionalized polyolefins are mainly used as additives in adhesive formulations, compatibilizing agents and aqueous dispersions. However, the low viscosity and functionality they offer has never been explored to generate high molecular weight products that offer improved processing routes for polyolefins as well as wider applications.

The aim of this thesis work was to investigate the preparation and characterization of thermoset material by reactions between a highly functionalized, low viscosity maleic anhydride grafted polyethylene and diamines. Reactions were performed both in solution and in the melt state to generate the target thermoset materials. Products from these reactions were extensively explored using different techniques to understand the reaction kinetics and mechanism. Thermosets generated were also characterized for the degree of crosslinking, thermal, mechanical and thermomechnical properties.

Reactions in solution showed that the degree of reaction could be easily controlled by manipulating the concentration of reactants in the reaction mixture. Mixing torque data from the melt blender generated during reactions in the melt phase suggested that reaction between anhydride and amine moieties in these systems happen at much slower rate than widely reported for conventional high molecular weight polymeric systems. Unlike a single or two closely merged peaks in mixing torque associated with melting of polymer and chain extension and crosslinking due to reaction between anhydride and amine functionality widely reported, two separate peaks were observed in this study. A combination of FTIR and insoluble fraction data generated suggested that the first peak observed in mixing torque represents a combination of melting and partial reaction between anhydride and amine functionality. Whereas, the second peak in the mixing torque represents the initiation of crosslinking. The slower kinetics observed in the current investigation was found not to be a consequence of immiscibility of polyether diamine and polyethylene or the relatively higher molecular weight of diamines utilized in some reactions since using a low molecular weight aliphatic diamine, hexamethylenediamine, produced similar trends. FTIR and gel content (insoluble fraction) data generated on the prepolymers by processing them at high temperatures, suggested residual anhydride presence in products which could not be assessed using FTIR. This observation renders the popular monitoring of anhydride peak in such systems to assess the degree of reaction highly questionable. Cured thermosets from the prepolymers produced showed gel fractions of the same scale as in traditional crosslinked products. DSC heat scans on the thermosets showed separate crystal populations for polyethylene in cured and uncured fraction. Dynamic mechanical analysis result showed the thermosets withstood temperature up to 200 °C without failure and a crosslink plateau could be observed following the melting transition. Tensile properties of the thermosets were observed to be promising and composition dependent.

These thermosets are expected to extend the polyolefins applications in areas like sealant, adhesive and coatings. The low viscosities of starting materials could also lead to new processing routes for polyolefins.

abstract: Doctor of Philosophy (PhD)


title: Cognitive reorganization and protective mechanisms in pregnancy and the postpartum period

contributor:
Rutherford, M.D.
Balshine, Sigal
Daly, Martin
Psychology

subject:
Pregnancy
cognition
recognition
nesting
adaptationist
threat
Cognitive Psychology
Psychology
Social and Behavioral Sciences
Cognitive Psychology

abstract: A clear picture describing cognitive change in pregnant women has yet to emerge. Recent work investigating pregnancy-induced cognition in women focuses on memory deficits, in contrast to the cognitive advantage and neural plasticity described in the nonhuman literature. The following thesis reviews the literature investigating pregnancy-induced cognitive change, and then reports three empirical studies investigating cognition in pregnant and postpartum women. I hypothesized that, given the high stakes associated with pregnancy and the postpartum period, adaptive mechanisms designed to keep the mother safe exist in the cognitive domain, in much the same way that Nausea and Vomiting in Pregnancy is now believed to buffer the mother and fetus from harm. The results of a meta-analysis and a longitudinal study comparing cognitive performance in pregnant and non-pregnant women suggest that there are cognitive costs associated with becoming a mother, in both pregnancy and the postpartum period. Recent research suggests that pregnant women possess an advantage in processing social stimuli: I report that pregnant women show facilitated recognition of faces. Finally, I examined nesting, and developed a questionnaire that tracked women through pregnancy and into the postpartum period, comparing non-pregnant women at similar time points. I report that nesting peaks in the third trimester, and involves space preparation and social withdrawal. Reproductive state affects cognition in ways that are distinct, and perhaps specialized, including a deficit in some areas (processing speed), and a cognitive advantage in others (face recognition), some of which may serve a protective function.

abstract: Doctor of Philosophy (PhD)


title: GALVANNEALING OF DUAL PHASE STEELS

contributor:
McDermid, J. R.
Materials Science and Engineering

subject:
Galvannealing
kinetics
dual phase
steel
oxidation
Wagner

abstract:
The high strength and ductility of dual phase (DP) steels makes them ideal for use in the automotive industry. However, to be used in automotive exposed parts galvanizing (GI) and galvannealing (GA) processes are essential to provide corrosion protection. Galvannealing of dual phase steels has three major steps: i) heat treatment of the steel strip to obtain a suitable substrate microstructure and reduce iron oxides at the substrate surface ii) dipping of the steel strip in the zinc bath to obtain a soft and ductile metallic zinc coating on the steel and iii) heat treatment of the coated substrate in the galvannealing furnace after removal from the zinc bath to form an Fe-Zn intermetallic coating on the steel.

The major challenges in galvannealing of dual phase steels are selective oxidation of the alloying elements used in DP steels such as Mn which may result in poor galvannealed coatings, and galvannealing time and temperature that can affect the microstructure and formation kinetics of galvannealed coating. Both of these issues have been investigated in this research using three industrial steel substrates: EDDS (Extra Deep Drawing Steel), CMn (Carbon Manganese) and DP590 (Dual Phase).The concentration of carbon, manganese and some other alloying elements was different in these substrates.

The effect of process atmosphere oxygen partial pressure on oxidation was determined for all experimental steels at dew point (dp) -30°C using a N2-5%H2 process atmosphere. The steel chemistry and oxygen partial pressure of the process atmosphere affected oxide thickness and morphology. For all alloys the lowest oxygen partial pressure process atmosphere resulted in the highest concentration and thickest oxide layer of Mn at the surface of dual phase steel (DP590). Also, the lowest segregation of Mn and thinnest oxide layer of Mn at the surface was obtained for the EDDS steel. The predominant oxide morphology observed at the surface of the DP590 steel comprised large oxide nodules or thick oxide films with irregular shaped/faceted nodules whereas the other two steels had an oxide morphology that generally comprised spherical cap shaped nodules at grain boundaries.

Four galvannealing times (10, 20, 30 and 40 s) and three galvannealing temperatures (480, 500 and 520 °C) were used to evaluate the effects of GA time/temperature on the microstructural evolution and formation kinetics of coating as a function of substrate Mn content. By increasing the galvannealing time and temperature, it was observed that for all steels, the Fe-Zn growth rate (alloying rate), thickness of gamma layer (Γ-Fe3Zn10) and iron content of the galvannealed coating were increased. It was concluded that galvannealing kinetics of DP and CMn steels at 480°C are faster than those of the EDDS steel. However, the galvannealing kinetics of DP and CMn steels at 500 and 520°C were relatively similar to each other and insignificantly different than those of EDDS. Accelerated galvannealing kinetics of higher Mn containing steels in this research, i.e. DP and CMn, could be ascribed to the presence of thicker oxide film/larger oxide particles at the surface that may have been reduced by aluminothermic reduction and accelerated inhibition layer breakdown. Considering the alloying rate and chemistry of the GA coating, it was found that 500 and 520 °C are not suitable industrial galvannealing temperatures for experimental steels in this research.

abstract: Master of Applied Science (MASc)


title: MULTIPLE INNER-LOOP CONTROL OF AN ELECTRO-HYDROSTATIC ACTUATOR

contributor:
Habibi, Saeid
Mechanical Engineering

subject:
Sliding Mode Control
Multiple Inner-Loop
Electro-Hydrostatic Actuator
Controls and Control Theory
Electro-Mechanical Systems
Controls and Control Theory

abstract:
Hydraulic systems are commonly used for actuation and manipulation of heavy loads. They are found in a variety of different industries, such as in automotive, manufacturing, robotics, construction, and aerospace. Conventional hydraulic systems use a centralized constant pressure supply system. Pressurized fluid is then channeled to actuators using servo-valves. The advantages of these systems are their high torque to mass ratio, and the ability to control speed and direction with relative precision. However, there are also disadvantages such as the requirement of a bulky centralized supply, leakage, noise, and reduced energy efficiency due to orifice flow and the requirement for maintaining a constant supply pressure.

Electro-Hydrostatic Actuation systems (EHA) alleviate many of the above mentioned shortcomings of servo-valve controlled hydraulic systems. In the EHA position control is achieved by regulating the pumping action. Here, a fixed or a variable displacement pump can be used to move oil from one chamber of the actuator to the other. In these actuators, the presence of nonlinearities associated with pump/motor static friction and backlash, pressure drop in the piping system, and nonlinear friction at the load have a significant effect on the performance and positional precision of the system.

This research will focus on developing a multiple inner-loop control strategy by implementing multiple inner-loops that utilize the differential pump/load position and velocity. The main goal will be to decrease the effect of the pump backlash as well as the nonlinear friction at the load; both of which negatively impact positional precision. Therefore, the main benefit of this method is an improvement in trajectory tracking precision, which is particularly important for high precision hydrostatic systems. Furthermore, a sliding mode control strategy will be incorporated into the design to suppress load oscillations reported in precision trajectory tracking applications. The research hypothesis states that sliding mode control in conjunction with multiple inner-loops, will improve the trajectory tracking performance of a hydrostatic actuation system by partially compensating the effects of static friction at the load. Theoretical analysis, simulation supported by experimental results are presented to demonstrate the effectiveness of the newly developed methods in suppressing the effects of nonlinearities on the EHA performance, with the downside of an increased complexity due to the increased number of controller parameters.

abstract: Doctor of Philosophy (PhD)


title: STRUCTURAL AND BIOCHEMICAL CHARACTERIZATION OF THE CHLAMYDIA PNEUMONIAE TYPE III SECRETION SYSTEM

contributor:
Mahony, James
Justin Nodwell, Brian Coombes
Medical Sciences

subject:
type III secretion
chlamydia
ATPase
effector
needle-tip
chaperone
Bacteria
Biochemistry
Structural Biology
Bacteria

abstract: Chlamydia pneumoniae is a Gram-negative intracellular pathogen that uses type III secretion to invade and survive within eukaryotic cells. The T3SS secretes specific effector proteins during the infection process to facilitate immune evasion and nutrient acquisition. Unfortunately, the genetic intractability and difficult culturing conditions of Chlamydiae has inhibited progress in the chlamydial T3S field. This thesis characterizes fundamental aspects of the C. pneumoniae injectisome such as the ATPase, the inner-membrane export apparatus, and a specific effector protein Cpn0803. Initially, we explored whether C. pneumoniae encodes a functional T3S ATPase and if it associates with other T3S components. We found that CdsN has enzymatic activity consistent with other Gram-negative T3S ATPases, and that CdsN associates with inner-membrane and soluble components such as CdsD, CdsQ, CopN and CdsL. We also found that CdsN has binding surfaces for either structural or putative effector / chaperone T3S proteins. Next, we explored the putative flagellar genes, which were of interest since Chlamydia is a non-motile bacteria that lacks flagellum. We found that the flagellar proteins associate with the T3S apparatus, suggesting that they play a role in T3S during the life-cycle. We extended this observation to show that CdsL, a T3S component, down-regulates both CdsN and FliI enzymatic activity, suggesting that the flagellar proteins are involved in T3S. Furthermore, we characterized Cpn0803 as an exemplary effector, which associates with both CdsN and FliI. We found that Cpn0803 is secreted into host cells upon Chlamydia infection. Cpn0803 was thought to be the T3S needle-tip protein; however, the crystal structure does not support this hypothesis. Presently, the actual role of Cpn0803 in the T3S apparatus remains unknown. Overall, our data suggests that CdsN and FliI both function during the chlamydial life-cycle in the T3S process, possibly coordinating effector proteins (such as Cpn0803) for secretion into host cells.

abstract: Doctor of Philosophy (PhD)


title: A Compositional Approach for Verifying Sampled-Data Supervisory Control

contributor:
Leduc, Ryan
Malik, Robi
Computing and Software

subject:
Discrete Event Systems
Supervisory Control
Sampled Data Supervisory Control
Compositional Verification
Controls and Control Theory
Controls and Control Theory

abstract: Sampled-data supervisory control deals with timed discrete event systems (TDES) where the supervisors are to be implemented as sampled-data controllers. A sampled-data controller views the system as a series of inputs and outputs and is controlled by a periodic clock. It samples its inputs, changes state, and updates its outputs on each clock edge (the tick event). The sampled-data supervisory control framework provides a set of conditions that the TDES system must satisfy to ensure its correct behaviour in order to be implemented as sampled data controllers. A serious limitation for automatic verification of systems is the size of the system's synchronous product. To overcome this limitation, we propose the use of a compositional approach to the verification of sampled-data supervisory control. In this approach, first we recast the required conditions for sampled-data supervisory control in terms of other properties such as language inclusion, nonblocking or controllability, which already have existing compositional methods and algorithms. This makes the sampled-data properties suitable for compositional verification, considerably increasing the size of systems that can be handled using sampled-data supervisory control. We also develop and implement a set of algorithms for the compositional verification of these sampled-data properties. We provide an example of the SD Controlled Flexible Manufacturing System to test our algorithms.

abstract: Master of Science (MSc)


title: SIMULATION OF OPTICAL DEVICES AND CIRCUITS USING TIME DOMAIN METHODS

contributor:
Huang, Wei-Ping
Electrical and Computer Engineering

subject:
FDTD
Complex mode expansion
dispersion
optics
Electromagnetics and photonics
Electromagnetics and photonics

abstract: A new model, referred to as the Rational Dispersion Model is proposed for modeling of dispersive materials in wide wavelength range using the Finite-Difference Time-Domain(FDTD) method. A hardware-accelerated FDTD method combined with the matrix pencil method is proposed to solve both guided and leaky modes. A circuit model based on the complex mode theory is proposed for analysis of large scale structures with non-negligible radiation effects.

abstract: Doctor of Philosophy (PhD)


title: CONTRIBUTION OF THE UNFOLDED PROTEIN RESPONSE (UPR) TO ADIPOGENESIS AND WHOLE BODY ENERGY HOMEOSTASIS

contributor:
Austin, Richard
Medical Sciences

subject: Endoplasmic Reticulum Stress

subject: TDAG51

subject: Adipocytes

subject: Obesity

subject: White Adipose Tissue

subject: Biochemical Phenomena, Metabolism, and Nutrition

subject: Endocrinology, Diabetes, and Metabolism

subject: Medical Cell Biology

abstract:
The endoplasmic reticulum (ER) is a specialized organelle that facilitates correct protein folding and maturation. Disruptions in ER homeostasis lead to ER stress and activation of a series of signal transduction cascades known as the unfolded protein response (UPR), which acts to restore ER homeostasis. In recent years, ER stress and UPR dysfunction have been linked to obesity, fatty liver and insulin resistance. Lipid-laden adipocytes, the main cellular component of white adipose tissue (WAT), play a critical role in whole body energy homeostasis as well as lipid and carbohydrate metabolism. Mature adipocytes, which are metabolically active endocrine cells, differentiate from precursor fibroblast-like preadipocytes, through a process called adipogenesis, leading to formation of cells capable of secreting numerous proteins, cytokines and hormones. ER homeostasis and UPR activation are essential to the function/differentiation of highly secretory cells, however, the role of ER stress/UPR activation in adipogenesis had previously not been examined. We hypothesized that adipogenesis may rely on physiological UPR activation to accommodate the demand on the ER for increased folding and secretion of proteins.

Initial experiments examining UPR activation during 3T3-L1 adipogenesis identified that expression of ER stress/UPR markers was modulated during adipocyte differentiation. Furthermore, inhibition of ER stress/UPR activation by the chemical chaperone, 4-phenyl butyric acid (4-PBA), inhibited adipogenesis and blunted high fat-diet induced weight gain in 4-PBA supplemented mice. These findings suggested that UPR activation modulates adipogenesis and adipose tissue metabolism.

Subsequently, we sought to identify novel candidate ER stress/UPR responsive genes that may be involved in adipogenesis and WAT metabolism. The expression of a recently recognized ER stress-responsive gene, T-cell death associated gene 51 (TDAG51) was identified to be differentially regulated during adipogenesis. However, the function of TDAG51 in adipogenesis or energy regulation was not known. Studies from this thesis showed that TDAG51 protein expression is attenuated by ER stress/UPR activation in preadipocytes and declines during adipogenesis. Based on these results, and given the importance of adipogenesis in WAT function and whole body energy metabolism, it was hypothesized that TDAG51 may be a novel regulator of adipogenesis and energy homeostasis. Indeed, as reported here, knock-down or absence of TDAG51 (TDAG51-/-) in pre-adipocytes increased lipogenesis and lead to earlier and more potent expression of adipogenic markers.

Finally, we investigated whether absence of TDAG51 in mice affected adiposity and metabolic outcomes. Consistent with the in vitro results, we found that TDAG51-/- mice fed a standard chow diet, exhibited an age-associated increase in WAT, developed fatty liver, and exhibited insulin resistance as compared to wild-type mice.

Taken together, the findings in this thesis indicate that physiological UPR activation and the UPR-responsive gene TDAG51 play important roles in regulating adipogenesis, lipogenesis and whole-body energy metabolism. Thus, therapeutic approaches aimed at modulating ER folding capacity, UPR activation and/or TDAG51 expression may have great potential in the treatment of obesity and its co-morbidities.

abstract: Doctor of Philosophy (PhD)


title: Parathyroid hormone-related protein in giant cell tumour of bone

contributor:
Singh, Gurmit
Medical Sciences

subject:
PTHrP
bone resorption
giant cell tumour
bone
RANKL
MMP-13
Medical Physiology
Medical Physiology

abstract: Giant cell tumour of bone (GCT) is an aggressive primary bone tumour with an unclear etiology that presents with significant local osteolysis due in part to the accumulation of multinucleated osteoclast-like giant cells. However, it is the neoplastic spindle-like stromal cells within GCT that largely direct the pathogenesis of the tumour. I hypothesize that parathyroid hormone-related protein (PTHrP) is a key mediator within GCT that promotes the characteristic osteolytic phenotype by stimulating both bone resorption and giant cell formation. The work presented in this thesis collectively demonstrates that the stromal cells express PTHrP and its receptor, the parathyroid hormone type 1 receptor (PTH1R), and that PTHrP acts in an autocrine/paracrine manner within the tumour to stimulate expression of factors that promote bone resorption. Data are presented that demonstrate that PTHrP stimulates stromal cell expression of the receptor activator of nuclear factor-κB ligand (RANKL), a known essential regulator of osteoclastogenesis, which results in increased formation of multinucleated cells from murine monocytes. Moreover, the GCT stromal cells express matrix metalloproteinase (MMP)-1 and MMP-13. These results suggest that the stromal cells may participate directly in bone resorption through the degradation of type I collagen, the promotion of osteoclast activity, or through a combination of these elements. PTHrP also regulates the expression of MMP-13 by the stromal cells. Experiments with CD40 ligand show that local factors present within the tumour can influence PTHrP expression by the stromal cells and potentiate its catabolic effects by stimulation of RANKL and MMP-13 expression. Together, this thesis presents evidence that suggests PTHrP is an important factor in the pathophysiology of GCT by its actions on promoting catabolism within the tumour. The role of PTHrP in normal physiology and the mechanisms of action presented here suggest that research into the effects of PTHrP within GCT may provide invaluable information that enhances our understanding of the biology of this particularly aggressive bone tumour.

abstract: Doctor of Philosophy (PhD)


title: Solution Studies of Meso-Tetra(p-sulphophenyl)porphine: Aggregation, Metallation and Potential Analytical Applications

contributor:
Corsini, A.
Chemistry

subject: Chemistry Chemistry

abstract:
Meso-tetra(p-sulphophenyl)porphine (TPPS₄), a synthetic water-soluble porphyrin, has been prepared in high purity and characterized in greater detail than previously reported. Several metal complexes of TPPS₄ have been prepared by a novel heterogeneous reaction. This simple reaction was also used in the synthesis of complexes of other porphyrins.

The solution behaviour of TPPS₄ was investigated by spectrophotometry and nuclear magnetic resonance methods, with a view toward ultimate analytical applications. In neutral or alkaline ionic media, TPPS₄ was found to dimerize, with KD = 1.58 x 10⁴ Mˉ¹. At higher concentrations, TPPS₄ was shown to aggregate further to tetrameric species, with KTT = 4-15 Mˉ¹. In acidic media, the behaviour of TPPS₄ was found to be complex and completely different from that observed in neutral media. A model involving micellization of TPPS₄ has been advanced to account for observations made in both the present work and that of other workers.

The kinetics of metal-ion incorporation, as exemplified by the reaction of Cu(II) with TPPS₄, was studied at pH 3.55. In general, the findings agreed with those of other workers, but an initial slow reaction, not previously reported, was found to occur under conditions favouring aggregation of TPPS₄.

The reactivity of TPPS₄ towards metal ions was examined in both neutral and acidic (pH 3.55) solutions. TPPS₄ showed kinetic and thermodynamic selectivity toward a relatively small group of metal ions, with the greatest selectivity towards Cu(II). The anionic metal complexes were found to be extractable as ion-associated species (with tetraphenyl-arsonium nitrate, for example) into organic solvents such as 1-pentanol. Based on these findings, an extraction-spectrophotometric method was developed for the determination of Cu(II), with a detection limit of 1.1 ppb. This limit compares favourably with those of atomic absorption and inductively-coupled plasma emission. With further development, the use of TPPS₄ as a complexing and preconcentration reagent in trace metal analysis appears to be most promising.

abstract: Doctor of Philosophy (PhD)


title: THE ROLE OF AMP-ACTIVATED PROTEIN KINASE (AMPK) IN MEDIATING RADIATION RESPONSES IN CANCER CELLS

contributor: Medical Sciences (Division of Physiology/Pharmacology)

subject:
AMPK
ionizing radiation
cancer
metabolism
cell signalling
Medicine and Health Sciences
Medicine and Health Sciences

abstract: One of the hallmark features of cancer is altered metabolism, whereby rates of glucose and fatty acid turnover are constitutively elevated to support uncontrolled propagation. The key regulator of energy metabolism is the enzyme AMP-activated protein kinase (AMPK), which suppresses anabolic pathways that increase proliferation and enhanced catabolic pathways that liberate energy, all in an attempt to maintain energy homeostasis in the cell. In addition to regulating metabolism, AMPK has also been implicated as a tumour suppressor and we have suggested that it may be a modulator of radiation responses in cancer cells in vitro. Moreover, we investigated the molecular mechanisms that facilitate ionizing radiation (IR)-induced AMPK activation, as well as demonstrated that certain AMPK activating drugs can work as radiation sensitizers in a variety of cancer cell lines. Stemming from this framework, we also provided experimental evidence that suggests AMPK is centrally involved in pathways that regulate DNA damage and proliferation at the basal level, and in response to IR. One of the targets involved in these pathways that can also influence AMPK regulation is the stress-activated Sestrin 2 protein. We have provided evidence that Sestrin 2 mediates IR-induced activation and expression of AMPK. Taken together, this work has provided novel insight into the ability of IR to modulate the activity and expression of AMPK, which in turn is required to facilitate the appropriate stress-response in cancer cells. Given its emerging interest in the cancer field, AMPK may become an important biomarker for evaluating clinical outcomes in patients undergoing radiation therapy.

abstract: Doctor of Philosophy (PhD)


title: CHARACTERIZATION OF CHILDREN AT-RISK FOR DEVELOPING ANXIETY DISORDERS: FINDINGS FROM CLINICAL ASSESSMENTS, BEHAVIOURAL DATA AND FUNCTIONAL MAGNETIC RESONANCE IMAGING

subject:
anxiety disorders
childhood anxiety
high-risk study
neuroimaging
fMRI
dot-probe task
Mental Disorders
Mental Disorders

abstract: The aim of this research study was to examine the clinical, behavioural and neurobiological characteristics of children who are considered to be at increased risk for developing anxiety disorders. The study population included high-risk children who have at least one parent with social phobia and normal-risk control subjects. The first objective of the study was to examine the prevalence of anxiety disorders in high-risk children. We determined the proportion of high-risk children who met criteria for a psychiatric disorder using structured clinical interviews and assessed symptom severity using measures of anxiety and depression. We found the prevalence of anxiety disorders to be elevated in high-risk children with 77% meeting criteria for a lifetime psychiatric disorder. High-risk subjects also had significantly higher levels of anxiety symptoms relative to normal-risk subjects. The second objective of the study was to examine threat-related attention processing in high-risk and normal-risk children using the dot-probe attention orienting task. We compared probe detection reaction times of high-risk children and normal-risk control children when they were exposed to emotional facial stimuli. We did not find any significant within-group or between-group differences in reaction times in our high-risk and normal-risk subjects. However, we did observe a trend towards longer reaction times in high-risk subjects for all trial types relative to normal-risk subjects, which could indicate general processing deficits in the high-risk group. The third objective of this study was to examine the activity of emotion processing brain regions using functional magnetic resonance imaging (fMRI) in children who are at increased risk for developing anxiety disorders. We compared the blood oxygenation level dependant (BOLD) response while high-risk and normal-risk subjects were engaged in the dot probe attention orienting task. Using fMRI, the BOLD response was measured while subjects were exposed to masked emotional (angry, happy or neutral) facial stimuli. We found increased activation of several frontal, temporal and limbic regions in high-risk subjects relative to normal-risk subjects during the presentation of emotional facial stimuli. These regions included the prefrontal cortex, anterior cingulate, hippocampus, insula, basal ganglia and temporal regions. To our knowledge this is the first study to characterize a sample of children at-risk for anxiety disorders using clinical, behavioural and neuroimaging data. The findings from this study demonstrate that high-risk children experience heightened anxiety symptoms and that they also present with functional abnormalities of brain regions involved in emotion processing. These results highlight the need for early identification and intervention for children at-risk for anxiety disorders. Future studies should aim for longitudinal study designs combined with neuroimaging techniques to examine changes in anxiety symptoms over time and to study the effects of treatment on the function of limbic and prefrontal structures in children at-risk for anxiety disorders.

abstract: Doctor of Philosophy (PhD)


title: AN EXAMINATION OF THE RESPONSE OF MAMMALIAN CELLS TO OXIDATIVE DNA DAMAGE IN RELATION TO AGEING AND NEURODEGENERATION USING RECOMBINANT ADENOVIRUS VECTORS

contributor:
Rainbow, Andrew J.
Bedard, Andre
Biology

subject:
DNA damage theory of ageing
base excision repair
host cell reactivation
recombinant adenovirus
8-oxoguanine
Cockayne syndrome
Biology
Cell Anatomy
Molecular Biology
Biology

abstract: Ageing is associated with a progressive decline in cognitive and physical function, as well as neurodegeneration. The DNA damage theory of ageing postulates that phenotypes associated with chronological ageing result from a time dependent accumulation of DNA damage caused by endogenously generated reactive oxygen species (ROS). In this work, we have used a host cell reactivation (HCR) technique to examine base excision repair (BER), the major pathway for removal of ROS generated damage, in fibroblasts from normal individuals and from patients with Cockayne syndrome (CS). The HCR assay utilizes an adenovirus encoded β-galactosidase (β-gal) reporter gene treated with methylene blue plus visible light (MB+VL) to measure BER of 7,8-dihydro-8-oxoguanine (8-oxoG). The results presented here demonstrate that host cell repair mechanisms remove MB+VL generated 8-oxoG from viral DNA and that reactivation of gene expression correlates with cellular repair capacity and requires CSA and CSB. Using the HCR assay, we demonstrate that culturing of primary human fibroblasts in media containing low levels of MB increases BER, suggesting increased DNA repair capacity may play a role in the therapeutic application of MB in Alzheimer’s disease treatment. We also demonstrate that BER decreases in vitro with increasing number of cell divisions, and that HCR of the damaged reporter gene is lower in fibroblasts from older donors. Using a second β-gal reporter gene assay, the enhanced expression assay, we were unable to show a relationship between the degree of decreased BER in CS and severity of clinical phenotype. However, we identified an interaction between CSB and the telomere protein TRF2. Overexpression of TRF2 leads to decreased nucleotide excision repair of UVC induced damage in a CSB dependent manner. We also demonstrate defective telomeres in the absence of functional CSB. The data presented in this work provide additional support for the DNA damage theory of ageing.

abstract: Doctor of Philosophy (PhD)


title: The Effects of Depleted Self-Regulation on Skilled Task Performance

contributor:
Martin Ginis, Kathleen A.
Kinesiology

subject:
self-regulation
ego depletion
sport psychology
EMG
darts
accuracy
Other Psychology
Other Psychology

abstract:
The purpose of this study was to examine the effects of depleted self-regulation on skillful task performance. Participants completed a baseline dart-tossing task (20 tosses), and were instructed to toss as quickly and as close to the bulls-eye as possible when a particular cue light flashed. Participants then underwent a self-regulatory depleting (experimental) or a non-depleting (control) manipulation before completing a second round of dart tossing. Measures of accuracy, reaction time, and myoelectrical activity of the biceps and triceps were collected along with self-report measures of psychological resilience and trait self-control.

As hypothesized, participants in the experimental condition had poorer mean accuracy at round two than control condition participants, as well as a significant decline in accuracy from round one to round two. These effects were moderated by trait self-control; experimental group participants with higher trait self-control were more accurate in round two than experimental group participants with lower trait self-control. Experimental group participants also demonstrated poorer consistency in accuracy compared to control group participants at round two, and a significant deterioration in consistency from round one to round two. The only significant finding regarding reaction time was that consistency improved significantly for the control group but not for the experimental group.

The results of this study provide evidence that ego depletion effects occur for skill-based physical task performance, especially in regards to accuracy. These findings provide further support for the utility of the limited strength model and suggest that self-regulatory depletion can impact performance on skill-based physical tasks.

abstract: Master of Science in Kinesiology


title: ECONOMIC EVALUATION OF AN INFLUENZA IMMUNIZATION PROGRAM

contributor:
Goeree, Ron
Loeb, Mark
Blackhouse, Gord
Health Research Methodology

subject:
Economic Evaluation
Cost Effectiveness Analysis
Influenza
Epidemiology
Epidemiology

abstract:
Objective: To estimate the cost-effectiveness of an influenza immunization strategy directed at healthy children 36 months to 15 years on the herd immunity of entire communities, versus not implementing this strategy.

Design: An economic evaluation, cost-effectiveness analysis (CEA). Costs and effects were estimated jointly with a two-stage bootstrap with shrinkage correction. Uncertainties around input parameters were tested with one-way and multi-way sensitivity analysis.

Data Sources: Effect and resource consumption data were from the Hutterite Influenza Prevention Study. Unit costs were collected from multiple sources including, government reports and schedules, local suppliers, peer-reviewed articles and systematic reviews, Internet searches and study data on file.

Outcomes: Mean costs and effects, incremental cost-effectiveness ratio (ICER), net monetary benefit (NMB) statistic and cost effectiveness acceptability curves (CEAC).

Results: The average cost per patient in the treatment arm was $69.08 and $32.66 in the control arm. The average number of influenza-free cases was of 0.96 in the treatment arm and 0.73 in the control arm. ICER was $164.19 per case of influenza averted, 95% confidence interval $28.38, $2,767.75. CEAC showed that at a willingness to pay of $177, the probability of the treatment strategy being cost effective compared to the control was 0.50. Results from sensitivity analyses were slightly different compared to base case results, supporting the robustness of base case estimates.

Conclusion: This strategy is likely to be cost effective relative to the comparator as the ICER estimate is low and because the estimate is conservative given that the study population was very healthy and the influenza season was mild. A more virulent season and a less healthy population would have produced a lower ICER or seen the treatment arm dominate the control.

abstract: Master of Science (MSc)


title: Accelerated Monte Carlo Based Simultaneous Dual-isotope SPECT Reconstruction

contributor:
Farncombe, Troy H.
Medical Physics

subject:
Monte Carlo
Dual isotope
SPECT
OSEM
Sim-OSEM
Diagnosis
Medical Biophysics
Nuclear
Other Physical Sciences and Mathematics
Other Physics
Diagnosis

abstract: Simultaneous dual-isotope SPECT imaging has a number of applications, for exam- ple, cardiac, brain and cancer imaging. The major concern in simultaneous dual- isotope SPECT is the significant crosstalk contamination between the different isotopes used. The current study focuses on a method of crosstalk compensation between two isotopes in simultaneous dual isotope SPECT acquisition applied to cancer imaging using 99mTc/111In and breast SPECT using 99mTc/123I. Monte Carlo (MC), which is thought to offer the most realistic crosstalk and scatter compensation modelling, in typical implementations, has inherent long calculation times (often several hours or days) associated with it. This makes MC unsuitable for clinical applications. We have previously incorporated convolution based forced detection into SIMIND Monte Carlo (MC) program which have made MC feasible to use in clinical time frames. In order to evaluate the accuracy of our accelerated MC program a number of point source simulation results were compared to experimentally acquired data in terms of spatial resolution and detector sensitivity. We have developed an iterative MC based image reconstruction technique that simulates the photon down-scatter from one isotope into the acquisition window of a second isotope. The MC based estimation of scatter contamination contained in projection views is then used to compensate for the photon contamination during iterative reconstruction. We use a modified ordered subset expectation maximization (OSEM) alogrithm, named as simultaneous ordered subset-expectation maximization (Sim-OSEM), to perform this step. We have undertaken a number of simulation tests and phantom studies to verify this approach in case of both of the dual-isotope combinations (i.e. 99mTc/111In and 99mTc/123I). In breast SPECT studies three different breast sizes were simulated. For each of the breast sizes ten combinations of lesions with 3 lesions per combination, were selected randomly for acquisition and reconstruction of simulation data. The images reconstructed using Sim-OSEM showed crosstalk compensation when compared with images reconstructed using simultaneously (with crosstalk) acquired projection data using analytical attenuation based reconstruction. In case of Sim-OSEM the lesion to background ratios were much closer to actual values compared to images reconstructed for both separately (without crosstalk) and simultaneously (with crosstalk) acquired projection data using analytical attenuation based reconstruction. Activity estimation is also possible with Sim-OSEM and yielded accurate estimates of lesion activities with relatively small error compared to deposited activities. The proposed reconstruction technique also evaluated by reconstruction of experimentally acquired projection phantom data in case of 99mTc/111In. Reconstruction using Sim-OSEM showed very promising results in terms of crosstalk and small angle scatter compensation and uniformity of background compared to analytical attenuation based reconstruction after triple energy window (TEW) based scatter correction of projection data. In our case images obtained using Sim-OSEM showed more uniform background even when compared to the images reconstructed for separately acquired projection data using analytical attenuation based reconstruction may be due to better correction of photons scattered at small angle and got detected under photopeak.

abstract: Master of Science (MSc)


title: The effect of lifelong maternal obesity on pregnancy outcomes and placental development

contributor:
Raha, Sandeep
Medical Sciences

subject: Obesity

subject: Placenta

subject: Vasculature

subject: Oxidative Stress

abstract: Maternal obesity is associated with an increased risk of pregnancy complications, including preeclampsia, miscarriage, birth of small for gestational age (SGA) babies, and stillbirth. Placental dysfunction has been implicated in all of these complications; however, the mechanisms by which maternal obesity influences placental development and function are not well understood. Female Sprague-Dawley rats were fed either a control diet (CON; 16% kcal from fat) or a high fat diet (HF; 45% kcal from fat) for 16 weeks beginning at weaning and were then mated with age-matched CON-fed males. This model emulates life-long obesity prior to pregnancy, a situation which is clinically relevant. Prior to pregnancy, HF-fed dams were 36% heavier and had significantly more abdominal fat. Dams were sacrificed at either gestational day (GD) 15 or GD18 to collect placental tissues. The remaining females were allowed to give birth naturally. HF-fed dams showed evidence of increased intrauterine death at GD15 and GD18. At birth, smaller litter sizes, offspring with reduced birthweight, and more stillbirths were observed in the HF-fed group. Placentas from HF-fed dams exhibited morphological changes at GD15, including an increased area covered by the labyrinth zone, an increase in blood vessel density and decrease in blood vessel maturity in the labyrinth layer, as well as increased carbonic anhydrase staining, indicative of hypoxia. These changes were associated with increased vascular endothelial growth factor (VEGF) protein levels and decreased placental growth factor (PlGF) protein levels. Both interstitial and endovascular trophoblast invasion into the maternal mesometrial triangles were increased at GD15. While these differences were no longer evident by GD18, placental morphometry demonstrated that the area covered by the labyrinth layer remained significantly greater in the HF-fed compared to CON-fed dams. Placental oxidative stress, which is often associated with placental dysfunction, was not observed at statistically significant levels at GD15. The early dysregulation of placental structure in HF-fed dams, which is normalized later in gestation, may play a role in the development of pregnancy complications associated with maternal obesity.

abstract: Master of Science (MSc)


title: INVESTIGATION OF THE CYTOPROTECTIVE EFFECTS OF SONIC HEDGEHOG IN CELLULAR AND ANIMAL MODELS OF AMYOTROPHIC LATERAL SCLEROSIS

contributor:
Turnbull, John
Doering, Laurie
Medical Sciences (Neurosciences)

subject:
Amyotrophic Lateral Sclerosis
Sonic hedgehog
excitotoxicity
Spinal motor neuron
neuroprotection
Life Sciences
Medicine and Health Sciences
Molecular and Cellular Neuroscience
Molecular Biology
Neuroscience and Neurobiology
Life Sciences

abstract: Amyotrophic Lateral Sclerosis (ALS) is a fatal progressive neurodegenerative disease with no known cause. Despite the efforts of investigators over the past 150 years, there remains no effective cure which substantially prolongs life. Therapeutic strategies have explored all of the proposed underlying pathological pathways of the disease from increased oxidative damage to impaired axonal transport, with little to no success. In the following pages, a novel perspective will be presented outlining the preliminary investigations of a new line of research demonstrating that Sonic hedgehog (Shh) protein and its agonists have cytoprotective effects on motor neurons. To begin these investigations, initial experiments were conducted in vitro utilizing a mouse hippocampal cell-line (HT-22) which served as a model for transient transfection and oxidative challenge assays. The results are reported in Chapter 2. Building upon these introductory findings, further investigations were conducted exploiting the SOD1G93A mouse model of ALS. Chapter 3 summarizes key observations pertaining to the abundance of a key cellular organelle in the sensing of Shh signalling, the primary cilium, in the spinal cord of SOD1G93A mice. In Chapter 4, a semi-quantitative analysis of the effects of Shh and Shh agonists pre-treatment in vitro on primary mixed spinal cord cultures are described. Subsequent challenge with an excitotoxic NMDA treatment was also conducted, as well as an in vivo survival study exploring the potential therapeutic effects of chronic Shh administration on SOD1G93A mice. The cumulative research presented here represents the very first investigation into the unique application of Shh and its agonists as potential therapeutic agents for the treatment of ALS, and our findings indicate that Shh has the potential of becoming a novel therapeutic agent for the treatment of ALS.

abstract: Doctor of Philosophy (Medical Science)


title: The Management and Sustainability of Organizational Change in Primary Care Adoption of Electronic Medical Record Systems

contributor: Teal McAteer, Ann McKibbon, Karim Keshavjee

subject: Electronic Medical Record

subject: EMR Adoption

subject: Primary Care

subject: Healthcare

subject: Small Business

subject: Change Management

subject: Change Management Model

subject: Information Technology failure factors

subject: Sustainability of Change

subject: Qualitative PEST Analysis

subject: EMR Adoption Model

subject: Entrepreneurial and Small Business Operations

subject: Health and Medical Administration

subject: Human Resources Management

subject: Management Information Systems

subject: Organizational Behavior and Theory

subject: Other Business

subject: Strategic Management Policy

subject: Technology and Innovation

abstract:
Information technology (IT) has been applied in every aspect in common everyday experience. Most industries have changed from paper based to digitally supported processes. The implementation of IT has resulted in lower costs, faster operations, and faster response to consumer demands, thus achieving economies of scale and major advancements in the quality of products introduced to the consumer.

In healthcare, IT has led to extensive advances in many different aspects of medicine. IT has enhanced diagnostic equipment, laboratory result accuracy, research methodologies and analysis advancements, and has resulted in more effective prescription of medications. These advances have increased the overall quality of life for patients.

Despite the fact that the adoption rate of Electronic Medical Record systems (EMRs) in European countries has reached more than 90%, the adoption of EMRs by primary care physicians in Canada lags far behind at a rate closer to 30%. Much of this low adoption rate can be attributed to barriers due to resistance to change. Many adoption projects in IT fail, even after change has occurred. These failures have occurred in many different industries, including healthcare. EMR adoption in primary care requires a focus on change management and sustainability for primary care physicians, the target audience of change.

This thesis research investigates the reasons for the low rate of adoption of EMRs in the primary care environment in Canada. A change management model dedicated to the Canadian primary healthcare environment for the management and sustainability of change is created and discussed in detail. This study is based on a thorough literature review of change management models; a qualitative analysis of interviews with industry leaders from different backgrounds such as consultancy, government, and vendors; and a quantitative analysis of data through an online primary care physician questionnaire.

abstract: Master of Science (MSc)


title: ANELASTIC BEHAVIOR AND DIFFRACTION MODELING OF SILICON CARBIDE WHISKER REINFORCED ALUMINA

contributor:
Wilkinson, David S.
Provatas, Nikolas
Jain, Mukesh
Materials Science and Engineering

subject: Anelastic Behavior

subject: SiC Whisker Reinforced Alumina Composites

subject: Finite Element Modeling

subject: Representative Volume Element

subject: Diffraction Peak Broadening

subject: Thermal Residual Stress

subject: Ceramic Materials

subject: Ceramic Materials

abstract:
The superior high-temperature elastic-plastic properties coupled with greater damage tolerance when compared with monolithic ceramics make ceramic matrix composites, CMCs, promising candidates for challenging applications such as engine components, rocket nozzles, cutting tools and nuclear energy reactor core components. Anelastic recovery is the time-dependent back strain observed upon the load removal following creep. In whisker-reinforced CMCs this can be a factor limiting operating conditions. Plastic strain misfit between two phases is thought to be the main driver in terms of the interactions within a percolating network. However, the network deformation mechanisms are still unclear and a previous neutron diffraction study showed an unexpected decrease of peak width after creep contradicting the theoretical predictions.

In this contribution, the finite element method (FEM) is applied to a representative volume element (RVE) with proper boundary conditions in order to simulate the creep deformation and hot pressing processes. Three geometries have been generated and studied: a 3D randomly-oriented short-fiber unit cell without fiber to fiber contact, generated by a random sequential adsorption algorithm; 3D regularly aligned single fiber unit cells; and 2D regularly aligned percolating unit cells. Deformation mechanism has been studied from an energy point of view and compared with a modified analytical model. Then a virtual diffraction model has been developed providing a framework to transfer information between the FEM simulations (strain fields) and the diffraction pattern in terms of the peak width (full width at half maximum: FWHM) and peak position as a measure of stress distribution and mean stress state respectively. Furthermore, the coupling effects of external stress, deformation mode, and thermal stress on the diffraction patterns have been studied.

The critical importance of a percolating whisker network for the anelastic recovery is demonstrated based on the 3D multi-whisker random unit cell. Whisker bending is shown to be the dominant mechanism over contact effects during the creep deformation of a composite containing a well aligned percolating whisker network based on the 2D unit cell model. Good qualitative agreement was found between our FEM simulations and the analytical model of Wilkinson and Pompe with regards to the maximum recoverable strain and the characteristic relaxation time. The analytical model captures all the critical factors characterizing the strain recovery, e.g., the effect of creep pre-exponent constant, whisker Young’s modulus and aspect ratio. Furthermore, it is found that the deformation from an initial stress-free state inevitably introduces peak broadening of whiskers inside the matrix. Several factors determine the peak-width and -shift, i.e., creep strain, applied stress, aspect ratio and geometry. However, thermal stress from the cooling stages following creep and hot pressing processes shelters this broadening effect and complicates the trends. Wide-ranging peak-width changes from narrowing to broadening are predicted depending on the geometry and applied stress. The peak position is shifted to a lower angle due to this thermal effect. This clearly explains the contradicting phenomena motivating this work and leads to that recommendation that a diffraction source with high angular resolution is needed to detect the subtle change of peak profile during creep.

abstract: Doctor of Philosophy (PhD)


title: Anisotropy of Magnetoconductivity of Metals

contributor:
Datars, W. R.
Physics

subject: Physics Physics

abstract:
The components of the electrical magnetoconductivity and magnetoresistivity tensors of aluminum and indium were calculated by the path-integral method using closed nearly-free electron Fermi surfaces and a uniform relaxation time. The anisotropy of the components is shown to depend primarily on the symmetry of the Fermi surface in relation to the magnetic field axis. The high-field longitudinal magnetoresistance is found to be a minimum for fields along high-symmetry directions, where the mean orbitally averaged longitudinal component of carrier velocity is a minimum. The anisotropy of the transverse magnetoresistance is larger in indium, which is face centered tetragonal, than in face-centered-cubic aluminum. The calculated Hall coefficients of both metals are isotropic in the high-field regime, but show considerable anisotropy for intermediate fields. The longitudinal-transverse components of magnetoresistivity can saturate at values as high as 0.26 of the zero-field resistivity, but the effects of the longitudinal-transverse magnetoconductivity components on the Hall coefficients and magnetoresistance are small. The calculated results are compared with experiment where possible, and are used to fit the induced torque data for aluminum. The theory reproduces the field dependence and anisotropy of the induced torque data. Induced torque experiments in the high-purity aluminum showed no linear magnetoresistance (slope < 10‾³) except for fields within ±3º of <100>. This anomaly was tentatively identified as due to open orbits resulting from magnetic breakdown. Calculations were done which show that the anisotropy of the transverse linear magnetoresistance observed in four-probe experiments cannot be due to an orbital enhancement of the semi-classical transverse conductivity.

The uniform relaxation time path-integral magneto-conductivity was also calculated for Ashcroft's (1963) Fermi surface model of aluminum for a <100> direction. The transverse magnetoresistivity and Hall coefficient were the same as for the nearly-free-electron Fermi surface, but the low-field resistivity and the high-field longitudinal magnetoresistivity were some 50% larger than the nearly-free-electron calculations, and the absolute value of the low-field Hall coefficient was some 20% smaller.

The effects of an anisotropic relaxation time on the calculations were also illustrated. Assuming a different relaxation time for the electron and hole bands was found to explain, qualitatively, the low-field Hall coefficients of indium and aluminum, and their temperature dependences. The effects of neglecting the nearly free electron α arms of indium were also calculated, and it was found that these effects should be separable from the effects of relaxation time anisotropy if the anisotropy as well as the field dependence of the Hall coefficients of a single sample could be measured.

The path-integral method was found to be a powerful, flexible and economical computational method which was capable of generating physically useful insight. When used with a complete Fermi surface (even a nearly-free electron one), and not just some subset of "representative" orbits, the calculations agreed quite well with experiments. The anisotropy of the magnetoresistivity components was found to be of much greater use in testing transport theories than was the field dependence or the values of the galvano-magnetic coefficients.

abstract: Doctor of Philosophy (PhD)


title: Synergetics of Nuclear Breeding Systems

contributor:
Harms, A.A.
Nuclear Engineering

subject:
Nuclear Engineering
Nuclear Engineering

abstract:
The role of nuclear energy systems while produce fissile materials has become an important and essential part of scenarios for the future development of nuclear energy. Definitive analyses and nucleonic comparisons of these breeder systems have been impeded by the lack of a rigorous and consistent methodology for describing fissile fuel production and fertile fuel utilization. The research reported here therefore addresses itself to this problem and is based on a synthesis of three concepts: (1) the lumped parameter formulation of reactor physics, (2) the establishment of symbiotic relationships between breeders and converters and (3) the use of material stockpile inventories.

In the lumped parameter synergetic analysis the temporal variation of stockpile inventories and net electrical output of a selected system are established. The system is taken to consist of a general breeder reactor coupled to a fission converter reactor and fuel reprocessing-fabrication plant. By including the converter and processing plant and examining the temporal and nuclear behaviour of the entire system, various types of nuclear breeders can be analysed and subjected to a comparative analysis in a consistent manner. The use of lumped parameters, based on the integration of detailed space and energy dependent effects into single-valued parameters, has facilitated survey calculations and analysis of the conceptual systems defined herein. The temporal variation of the stockpile inventory is used to describe fissile fuel production and fertile fuel utilization since information, such as minimum inventory requirements and material replacement times, is provided. This approach eliminates the ambiguities involved in a single figure of merit description, such as, for example, the doubling time, and includes pre-steady-state effects and reprocessing lags and losses. To assess the net electrical production of the system, the consumption of electricity by the reactors and the processing plant is explicitly included.

The synergetics of fast-fission, symbiotic fusion, hybrid fusion and spallation breeders are then investigated. In these analyses, the fissile and fertile inventories and power output are calculated over the system lifetime for a specific breeder power. The effects on the system inventories of varying breeder thermal power are also examined. Since the mathematical-physical formulations are specified in terms of lumped parameters, the results of changing these on the system can be easily dealt with. Four fissile fuel breeding systems are then compared using current economic data.

On the basis of this study, it is evident that there exists no single breeder system which consistently outperforms the others in all aspects. The fast-fission breeder, while not a good fissile fuel producer, has the best power generating efficiency and, due to its relatively low capital costs, can produce electricity at the lowest cost. The symbiotic fusion breeder system has the shortest fissile fuel replacement time and requires less initial fuel investment but it produces electricity at the highest cost. For combined fissile fuel production and electrical generation, the hybrid fusion breeder excells and it is also a good conserver of fertile fuel. The spallation breeder outranks all others in fissile fuel production.

While no single breeder was found to be superior in a general sense, the synergetics method of analysis has been shown to be effective in several specific respects. The temporal variations of the stockpile inventories and net power derived here have a physically reasonable basis and are mathematically tractable. The pre-steady-state effects can be described with great accuracy by two functions determined by the fuel management scheme. Processing lags and losses are also explicitly incorporated. The flexibility and usefulness of the developed methodology are enhanced by the fact that any material stockpile inventory in the system can be calculated. Essential to this procedure is the inclusion at the outset of all system components in a synergetic analysis.

abstract: Doctor of Philosophy (PhD)


title: NURSE MIGRATION INTENTIONS IN A CANADIAN BORDER CITY

contributor:
Andrea Baumann PhD, RN
Nursing

subject:
nurse migration
concept analysis
case study methodology
value-expectancy framework
integrative review
commuter migrant
web-based survey
mixed methods
border city
nurse graduates
Human Resources Management
International and Area Studies
Nursing
Other Education
Human Resources Management

abstract:
Background. The nursing profession has a long tradition of migration. The migration of nurses from Canada has received little attention.

Objective. The purpose of this sandwich thesis was to understand the migration intentions of nurse graduates in a Canadian border city, their intention to become commuter migrants, and to explore the factors influencing these intentions.

Methods. Two qualitative studies of the migration literature included an analysis of the concept of migration and an integrative review of case study methodology in the study of nurse migration. A mixed methods study, guided by the Value-Expectancy framework, explored the migration intentions of nurse graduates in a Canadian border city and the factors influencing these intentions.

Results. The concept of nurse migration was found to be multifaceted. Its attributes, antecedents and consequences were defined. The mixed methods study provided insights into the migration intentions of recently graduated Canadian nurses. The majority preferred to work in Canada, but because of a perceived absence of valued jobs factors, were willing to migrate. Two thirds considered migrating and sixteen percent were interested in becoming commuter migrants. The findings supported the hypothesis that nurses weigh employment values (goals) against the expectation of achieving them, thus influencing intentions to migrate or stay.

Conclusion. The value-expectancy framework offered a novel approach for identifying the job factors that were driving migration intentions. There is a need for more primary research employing different methodologies to explore the characteristics, causes, and consequences of nurse migration that were identified through this research.

abstract: Doctor of Philosophy (PhD)


title: Wildfire Impacts on Peatland Ecohydrology

contributor:
Waddington, J.M.
Geography and Earth Sciences

subject:
Peatland
ecohydrology
wildfire
Sphagnum
Alberta
vadose zone
Hydrology
Hydrology

abstract:
The objective of this thesis is to examine the changes to peatland ecohydrological processes as a result of wildfire disturbance in forested ombrotrophic peatlands of the Boreal Plains. The hydrology and atmospheric exchanges of energy and water were examined at two peatlands in northern Alberta: one recently burned and the other approximately 75 years since fire.

Wildfire resulted in little change in net radiation flux to the peatland during the snow-free period. A decrease in the net radiation flux during the late winter was caused by the loss of the tree canopy and the increase in albedo during winter. While summer albedo largely returned to pre-fire values within two years after fire, the amount of solar radiation reaching the burned peat surface increased by nearly 50%. As a result, surface evaporation increased by an amount only marginally greater than the loss of transpiration. The net result on the water balance was a modest increase in water losses during the course of the summer, resulting in a lower water table. Water table decline per unit of evaporation was higher due to a decrease in specific yield, likely from a combination of post-fire peat compression and the combustion of high specific yield surface peat during wildfire. The combination of lower water table and enhanced evaporation cause greater pore-water pressures after fire, particularly in hummocks. The hydrological regime of hollows was not significantly altered by wildfire, despite the larger depth of burn in the hollows.

abstract: Doctor of Philosophy (PhD)


title: Synthesis of Silica Shell/Gold Core Nanoparticles and Plasmonic Characterization of the Aggregates

contributor:
Brook, Michael A.
Chemical Biology

subject:
core-shell
nanotechnology
diglycerylsilane
AuNP
Materials Chemistry
Polymer Chemistry
Materials Chemistry

abstract: Differences in the wavelengths of the surface plasmon band of gold nanoparticles (AuNP) – before and after particle aggregation – are widely used in bioanalytical assays. However, the gold surfaces in such bioassays can suffer from exchange and desorption of non-covalently bound ligands and from non-specific adsorption of bio-molecules. Silica shells on the surfaces of the gold can extend the available surface chemistries for bioconjugation and potentially avoid these issues. Therefore, silica was grown on gold surfaces primed with polyvinylpyrrolidone (PVP) using either hydrolysis/condensation of tetraethyl orthosilicate under basic conditions or diglycerylsilane at neutral pH. The former precursor permitted slow, controlled growth of shells from about 1.7 to 4.3 nm thickness. By contrast, silica shells formed within an hour using diglyceroxysilane; the thickness was insensitive to changes in silane concentration and incubation time and could be tuned using different molecular weight PVP to prime the particles. The control over shell thickness is discussed with respect to the PVP interface, the electrical double layer, and interpenetrating organic-inorganic hybrid structures. Within the range of shell thicknesses synthesized, the presence of a silica shell on the gold nanoparticles did not significantly affect the absorbance maximum (~ 5 nm) of unaggregated particles. However, the change in absorbance wavelength upon aggregation of the particles was highly dependent on the thickness of the shell. With silica shells coating the AuNP, there was a significant decrease in the absorbance maximum of the aggregated particles, from ~578 to ~536 nm, as the shell thicknesses increased from ~1.7 to ~4.3 nm, due to increased distance between adjacent gold cores. These studies provide guidance for the iv development of colorimetric assays using silica coated AuNP. Such particles also show potential for application in 2D and 3D nanostructured assemblies.

abstract: Master of Science (MSc)


title: MULTI-FREQUENCY GROUND-PENETRATING RADAR (GPR) STUDY OF GLACIOFLUVIAL OUTWASH DEPOSITS, LIMEHOUSE, ONTARIO

contributor:
Boyce, Joe
Geography and Earth Sciences

subject: Geology Geology

abstract:
In this study, the spatial trends in heterogeneity and sedimentary architecture of a coarse-grained glaciofluvial deposit were investigated in a gravel pit near Limehouse, Ontario using multi-frequency ground-penetrating radar (GPR). The well-exposed outcrops in the pit (> 10 m) allow direct comparison of radar and outcrop lithofacies and provide ‘outcrop analogues’ for regional glaciofluvial aquifers present in the shallow subsurface. GPR surveys were acquired using four different frequencies (25, 50, 100 and 250 MHz) over a 5800 m² grid on the pit floor and along an adjacent outcrop and roadway. Profiles were acquired at 2 m line spacing using D-GPS positioning and processed to a quasi-3D volume in GPR-SLICE software.

Radar reflection patterns were grouped into radar facies and interpreted using architectural element analysis (AEA) with reference to outcrops and a nearby geophysically logged borehole (MW-22). Using this approach, five distinctive lithosomes and two depositional phases were identified. The lithosomes consist of gravel clinoform (GC) elements, gravel bar (GB) and gravel foreset (GF) elements, vertical aggradation (VA) elements and incised channel elements (CH). RP-1 (elements GC, CH, GB) records the progradation of a sub-aqueous fan delta into a shallow proglacial lake. RP-2 records a subsequent phase of incision of deltaic deposits by glaciofluvial spillways and infilling of channels by aggradation of braided river sand and gravel deposits.

Comparison of the radar profiles with borehole and outcrop data indicates that lithosome bounding surfaces are associated with major changes in sediment texture. Lithosomes defined using radar reflection patterns can therefore be used to predict changes in sediment grain size and associated hydrogeologic parameters (e.g. hydraulic conductivity). These results demonstrate that multi-frequency GPR is a viable approach for evaluating spatial trends in sedimentary heterogeneity and can be applied at other sites under consideration for artificial recharge projects.

abstract: Master of Science (MSc)


title: THE ROLE OF TEMPORAL FINE STRUCTURE CUES IN SPEECH PERCEPTION

contributor:
Bruce, Ian C.
Electrical and Computer Engineering

subject:
Speech perception
temporal fine structure
envelope recovery
Biomedical
Signal Processing
Biomedical

abstract: In this thesis, the importance of temporal fine structure (TFS) in speech perception is investigated. It is well accepted that TFS is important for sound localization and pitch perception, while envelope (ENV) is primarily responsible for speech perception. Recently, a significant contribution of TFS in speech perception has been suggested. This was linked to the improved ability of normal-hearing subjects to understand speech in fluctuating-power background noise as compared to hearing-impaired people. However, the accuracy of this claim is questionable since TFS and ENV are correlated and one can recover ENV to some extent if provided with TFS-only speech. In this work, we quantify the relative advantages of TFS and the possible influence of recovered ENV on speech recognition scores. We used a computational model for the cat auditory periphery, which was modified to match the available data for human cochlear tuning. The output of the model was analyzed by the spectro-temporal modulation index (STMI) metric to predict speech intelligibility. A speech recognition experiment was conducted on five normal-hearing subjects and the STMI predictions were mapped to intelligibility using a specially constructed mapping function. The TFS role was quantified by examining the TFS intelligibility scores and the corresponding intelligibility predictions from ENV recovery. Our results show that although ENV recovery has some influence on the intelligibility results, it cannot account for the total reported intelligibility.

abstract: Doctor of Philosophy (PhD)


title: DYE-SENSITIZED SOLAR CELLS WITH A SOLID HOLE CONDUCTOR

contributor:
Xu, Gu
Materials Science and Engineering

subject:
Dye-sensitized Solar Cells
Polymer and Organic Materials
Semiconductor and Optical Materials
Polymer and Organic Materials

abstract: Dye-sensitized Solar Cells (DSSCs) with liquid electrolyte lack long term stability because of volatility of the electrolyte and assembly problems. Replacement of the volatile liquid-state electrolyte with solid-state hole conductor thus becomes necessary. A small molecule based hole conductor, Copper Phthalocyanine (CuPc), is proposed here to replace the liquid electrolyte, for its intrinsic thermal and chemical stabilities. However, a lower short circuit current was found in the CuPc solid state device from I-V curve, which is closely related to the inefficient hole transport in the CuPc thin film. Therefore, Two-Dimensional Grazing Incidence X-ray Diffraction (2D GIXRD) is utilized to study the phase and texture of CuPc thin film. It is found that the CuPc thin film has a cystallinity of greater than 80%, which is good for hole conducting. However, the β-phase formation lowers the overall hole conductivity. The hole conductivity of β-phase CuPc is two orders of magnitude smaller than that of α-phase CuPc, due to a less overlap in the π-π stacking. As a result, the low hole conductivity of β-phase CuPc is the reason that leads to an inefficient hole transport and reduces the short-circuit current of the solid-state DSSC. Therefore, future work will be necessary to isolate α-phase CuPc, in order to be successfully applied into the solid-state DSSCs.

abstract: Master of Science (MSc)


title: Development and Application of Policy-Based Tools for Institutional Green Buildings

contributor:
Baetz, Brian W.
Samir Chidiac; Ashish Pujari
Civil Engineering

subject:
Policy
LEED
Green Buildings
Rainwater Harvesting
Water Conservation
Water Quality
Civil Engineering
Civil Engineering

abstract:
Abstract

An opportunity exists to enhance policy development and application in higher education as it relates to the promotion of sustainable building practices and the application of Leadership in Energy and Environmental Design (LEED®) principles. No previous research has been conducted to determine if policy instruments are essential for sustainable building practices, together with the use of LEED®, for the implementation of institutional green buildings in North America.

The primary research goal is to determine if policy is essential for sustainable building practices and the implementation of LEED® for new construction and major renovations in higher education buildings in Canada and the United States. A specific focus on water conservation and water quality is undertaken related to green buildings. A comprehensive quantitative web-based survey was developed and administered to poll members of APPA (formerly the Association of Physical Plant Administrators) on their use of policies or other instruments for sustainable development and the specific use of LEED® applications for new construction and major renovations on their campuses. Qualitative telephone interviews were conducted with a subset of the survey respondents to explore and supplement components of the survey and to gain greater insight as to the strategic application of sustainable facility initiatives at their respective institutions. A sustainable building policy template is developed for application to the higher education sector.

Using a mixed-methods approach has provided clear evidence that these institutions are contributing to the growth in sustainable practices in higher education and that the facility professionals are contributing to much needed leadership in this field. Institutions that have implemented sustainable/green building policies for their new buildings or major renovations are exhibiting policy compliance and meeting their LEED® targets, while some institutions that utilize non-policy practices are not complying.

This research provides a framework for an institutional sustainable building policy that is suitable for use as a template for senior facility professionals and their specific policy development. This work contributes to a foundation for future research related to sustainable/green building policy development and its application to the higher education sector.

A review of survey participants’ water conservation approaches was undertaken with a specific application to a rainwater harvesting-to-potable water system in the Engineering Technology Building (ETB) at McMaster University. Field research was undertaken on the evaluation of three white roof membranes: modified bitumen finish ply, polyvinylchloride (PVC), and thermoplastic polyolefin (TPO); and their effects on the runoff water quality were studied. An analysis of the quality of rainwater runoff was performed from each of these three membranes and compared to Ontario provincial drinking water standards. Analyses were performed to determine if there is a preferred membrane for this function.

Results of the water quality testing and analysis indicate that the selected white roof membranes will provide a suitable catchment surface for a green building and/or use in a rainwater collection system. When compared to Ontario’s MOE water quality requirements, no particular roof membrane of the three researched (modified bitumen, PVC and TPO) provided superior water quality results to suggest that either was preferred or recommended as a rainwater harvesting (RWH) catchment surface.

This research has revealed that higher education institutions are engaging in water conservation practices across Canada and the United States. Operational challenges are evident, particularly as they relate to waterless urinals. The ETB system that harvests rainwater and provides treatment to potable standards is showing significant promise for future site–based solutions.

abstract: Doctor of Philosophy (PhD)


title: Assessing change in fish habitat and communities in coastal wetlands of Georgian Bay

contributor:
Chow-Fraser, Patricia
Stone, Jonathon
Dushoff, Jonathan
Biology

subject:
Coastal Wetlands
Northern Pike
Remote Sensing
Inventory
Mapping
Water Levels
Terrestrial and Aquatic Ecology
Terrestrial and Aquatic Ecology

abstract:
Aquatic vegetation in the pristine coastal marshes of eastern Georgian Bay (GB) provides critical spawning and foraging habitat for fish species, with complex habitat supporting the greatest diversity. These wetlands are threatened by a changing water level regime and forecasted lower water levels. To monitor and conserve these wetlands, we must understand how they function and respond to this stressor. The overall goals of this thesis are to determine the impact of declining water levels on both wetland fish habitat and the fish community as well as identify the spatial scale of habitat utilization by fishes.

We first delineate all coastal wetlands in eastern GB, identifying 3771 wetlands that provide habitat for Great Lakes fishes. Using satellite imagery, we develop an object-based classification method to classify four types of wetland vegetation. Since submerged aquatic vegetation (SAV) is not visible from satellite imagery in GB, we develop a model to predict potential area of this important habitat. The model suggests that the response of SAV to declining water levels depends on wetland geomorphology, but generally, the area of SAV decreases. To assess the response of fish habitat coverage and structure to sustained low-water levels, we classify vegetation in images collected in 2002 and 2008. The result is increasingly homogeneous habitat, a net loss of fish habitat and a decrease in fish species richness. Finally, mark-recapture and radio-tracking are used to evaluate fish movement among closely situated wetlands. Results suggest that the current distance used to group and protect small wetlands provincially (750 m), likely protects most resident fish species, but does not cover movement patterns of a top predator. This research will advance our scientific understanding of freshwater coastal ecosystems and aid in the creation of conservation strategies to mitigate future threats from declining water levels.

abstract: Doctor of Philosophy (PhD)


title: EFFECTS OF AGRICULTURAL PRACTICE ON THE WATER QUALITY OF LOW-ORDER STREAMS IN THE BEAVER VALLEY WATERSHED

contributor:
Chow-Fraser, Patrica
Waddington, Michael J.
Dudley, Susan
Biology

subject:
agriculture
low-order streams
water chemistry
algae
eutrophication
livestock
storm events
periphyton
stream order
Agriculture
Agriculture

abstract: Eutrophication from agricultural runoff is a global issue, and can often result in degradation and loss of aquatic habitat. The overall objective of this study is to gain a better understanding of the factors that influence variation in water chemistry of low-order streams in an agricultural watershed. The first chapter finds significant differences between the effects of livestock- vs and crop-based operations on water chemistry while modeling the relationship between independent landscape variables and major water-quality parameters in an agroecosystem. I also determine significant differences exist in dependent variables among seasons and are best described by the agriculturally relevant calendar (ARC). In Chapter 2, I compared the effectiveness of discrete and continuous sampling programs for monitoring the impacts of cattle disturbances on water quality. I found that daily total phosphorus (TP) concentrations (integrated sample taken every 6 hours) were not significantly correlated with precipitation and were significantly lower than discrete water samples. Turbidity readings (recorded every half hour) showed spikes that corresponded with cattle hydration events and increased levels of nutrients through backwash. . In Chapter 3, I find a significant relationship between periphyton growth and the level of primary nutrients (TP, soluble reactive phosphorus, total-ammonia nitrogen). Thus, for low-order streams influenced by small family farms, acrylic rods may be an inexpensive indicator of excess limiting nutrients. In such environments stream length may be a stronger measure of streams than stream order since total nitrogen, TP and pH were significantly correlated with stream length.

abstract: Master of Science (MSc)


title: The Partridge Island Site: Early and Middle Woodland-Related Assemblages in Passamaquoddy Bay

contributor:
Sutherland, Patricia
Anthropology

subject: Anthropology Anthropology

abstract:
This thesis deals primarily with the description and analysis of archaeological material excavated at the Partridge Island site. A secondary focus is the assessment of assemblage variation, reflecting differences in site utilization, between island and mainland sites in Passamaquoddy Bay, New Brunswick.

Artifacts, features and supporting faunal data from two Partridge Island components are examined, first to ascertain the position of Partridge Island in relation to chronological sequences suggested for the Maine/Maritimes region. Comparison between Partridge Island assemblages and those from contemporaneous mainland sites is then provided.

The result of analysis of the Partridge Island data indicates that the site compares well with other Early and Middle Woodland-related assemblages throughout the Maine/Maritimes region. The sole exception to this is the presence of well documented and dated features, diagnostic artifacts and faunal remains, predating circa 2,000 B.P. that have not been identifi,ed elsewbere. Comparisons of artifact and feature forms from island and mainland sites do not suggest differing utilization of island and mainland sites, however, no firm conclusions can be drawn.

The problems of comparing sites in Passamaquoddy Bay are discussed and suggestions are offered for the, direction of future research.

abstract: Master of Arts (MA)


title: The Effect of the Inlet Boundary Layer on the Secondary Flow in an Annular Cascade

contributor:
Wade, J.H.T.
Mechanical Engineering

subject:
Mechanical Engineering
Mechanical Engineering

abstract:
The development of small gas turbine units with high specific output calls for the design and testing of rotor cascades with high turning blades. A major portion of the losses that occur in such cascades are associated with the secondary flow. The need for experimental data of highly loaded annular cascades can be readily seen from a review of the available literature.

The objective of this study was to construct and test an annular test rig of special configuration particularly suited for high turning blades. The rig was an open circuit wind tunnel with inlet and exit ducts of hyperboloidal shape. The test facility provided a means for adjusting the inlet flow in the circumferential direction (to ensure periodicity) as well as controlling the inlet endwall boundary layers. The cascade tests were conducted at a Reynolds number of 4.73x10⁵ based on the blade chord. Extensive flow measurements were taken at the inlet and the exit from the cascade both in the main stream and the endwall boundary layers. The passage walls static pressure distribution was also measured. Maps of the exit flow parameters were presented for the total pressure loss coefficient, static pressure coefficient and the secondary flow velocity vectors. The averaged flow parameters were analysed and the losses were compared with several predictive correlations. The measured losses were found comparatively lower than the predicted.

A flow visualization study was carried out using smoke in the air stream and oil film (lamp-black and kerosene) on the passage walls. The results thus obtained were consistent with the general flow picture depicted from the analysis of the measured data.

abstract: Doctor of Philosophy (PhD)