title: Mount Hope Noise Survey: Present Levels And Predicted Increases with Expansion

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

subject: Mount Hope, noise, expansion, noise levels, Mount Hope Airport, subsonic jet aircraft, runway facilities, traffic density, paterns, configurations

abstract:
 This study deals with applied research in the field of environmentai noise problems, specifically the measuring of noise patterns near Mount Hope Airport originating from subsonic jet aircraft using the present runway facilities. Based on actual measurements the results have been analyzed and reduced to simple contour lines.

An attempt has been made in this study to relate the concept of community noise in the vicinity of the airport to specific runway configurations, traffic density and patterns, and to provide a comparison between the noise levels due to the existing operations
and those which may result due to the proposed expansion.
Versatile computer programs have been developed in this study
to simulate an airport model, compute and construct the noise
contours for any combination of design requirements such as
runway orientation, flight procedure, type of aircraft, etc

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: The Effects of Sb, In, and Sn Doping on the Optical Properties of Tin Dioxide (Part A)

contributor:
Marton, J.P.
Engineering Physics

subject: tin dioxide, optical, doping, properties, material, concentration

abstract: This is Part A of the Thesis. Here is the Link to Part B: http://hdl.handle.net/11375/17845

abstract:
 This study was focused on the absorption spectra of tin dioxide thin films on optical quartz substrates. The films were doped with antimony from zero to ten percent, indium from zero to ten percent, and intrinsically, by heating undoped samples in vacuum and air. The surface resistances were also measured.

 The results for antimony doping show that the energy required for electron transitions from valence to conduction bands, the associated
phonon energies, and the optical absorption by free carriers all increase while resistance decreases with increased doping. These results are consistant with antimony acting as a donor in SnO2 and elevating the Fermi level, which is in the conduction band for the
undoped material, to a higher level, thus increasing the free carrier concentration. The results possibly also indicate a strain on the lattice caused by doping.

 The results for indium doping show a similar increase in energies along with a decrease in optical absorption by free carriers and an increase in resistance with increased doping. The indium acts
as an acceptor and, in so doing, causes the Fermi level to drop into the valence band, at the doping levels used in this study. This is probably due to the formation of an acceptor band above or overlapping the valence band and resulting in a reduction of the free carrier concentration. The increase in phonon energy indicates that the doping imposes a strain on the lattice.

 Heating undoped films in vacuum appears to drive off oxygen
resulting in reduced resistance and therefore higher free carrier concentration due to lattice defect doping, and reduced valence to conduction band transition energy possibly due to the formation of a conduction band in the forbidden band-gap. The changes were reversible by re-heating in air.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: The Effects of Sb and B Doping on the Conductive Properties of Tin Dioxide (Part B)

subject: tin dioxide, conductive, doping, substrates, boron, concentration

abstract: This is Part B of the Thesis. Here is the Link to Part A: http://hdl.handle.net/11375/17844

abstract:
 This report deals with the effects of various parameters on the resistance and the temperature coefficient of resistance (or the T.C.) of tin dioxide films doped with antimony and boron. The films were produced on cylindrical ceramic substrates by the hydrolysis of SnCl4 and SbCls in the presence of HCl and H3BO3. The T.C. was measured over the range of 25 to 150°C and averaged.

 Under normal conditions, the films were produced at 950°C with an antimony concentration of 0.457 molar % and a boron concentration of 2.73 molar %. Varying this firing temperature (from 800-1100°C) was found to have no effect on the resistance but increased the T.C. by 2 to 3 ppm/°C per degree change. Varying the antimony content from 0 to about 1 molar % was found to have little effect on resistance. The effect on T.C. was to increase it at lower Sb levels and then to decrease the T.C. as the level increased.

 Varying the boron content (0 to 4.46 molar %) was also found to have little effect on resistance. A decrease in T.C. with boron content was noted when only the boron was varied, but an increase in T.C. was found when HCl and H2O volumes were varied with the boron. The introduction of additional air into the system was found to have no effect.

 Film thicknesses were varied by controlling the chemical flowrates. Thinner films were found to have dramatically higher resistances and reduced T.C. values. It was observed that below a certain flowrate resistive failure occurred in the films. It was found in this study that within the statistical distribution of film values, those samples with above average resistance had below average T.C. values and vice-versa. Annealing in vacuum at 500°C was found to produce samples of reduced resistance and increased T.C. while the opposite was found with air annealed samples. Quickly cooled samples were found to be more stable.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: The Binding Energy of the Triton Using Repulsive Core Potentials

contributor:
Preston, M.A.
Physics

subject: repulsive, energy, binding, nucleus, core

abstract: The binding energy of the tritium nucleus is calculated by the variational method, using static repulsive core potentials.

abstract: Thesis

abstract: Master of Science (MSc)


title: FM Threshold Performance of the Phase-Locked Oscillator

contributor:
Gladwin, A.S.
Electrical Engineering

subject: threshold, phase-locked, oscillator, FM, demodulator,

abstract:
 This thesis is principally concerned with the performance of the phase-locked FM demodulator under conditions of interference in comparison to the conventional FM demodulator. The linear no interference performance of the phase-locked oscillator is well known, however this aspect is included in the interests of completeness and reference.

 Mechanisms tor threshold effects in the phase-locked and conventional FM demodulator are discussed and compared. It is shown theoretically and experimentally that the noise threshold is reduced in the phase-locked FM demodulator by virtue of the limits of Ψi (t) being restricted by the noise bandwidth of' the feedback loop. Fall off in baseband signal level in the presence of noise was seen to be a function of θ(t) and (S/N)IF.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Chronic pain: A Red Herring or Risk Factor in the Management of Patients Receiving Opioid Substitution Therapy

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
methadone
chronic pain
addiction
opioid substitution therapy
methadone maintenance treatment

abstract:
Background: The consequences of continued opioid abuse among patients treated with opioid substitution therapy (OST) are serious and can result in abnormal cardiovascular function, overdose, and mortality. Conflicting evidence exists that both implicates and refutes the role of chronic non-cancer pain (CNCP) as a major risk factor for continued opioid abuse within the addiction treatment setting. This thesis aims to 1) evaluate the impact of chronic pain on the treatment outcomes of patients with opioid addiction receiving OST, 2) determine whether a clinical or inflammatory profile exists to distinguish pain in this population, 3) explore the sources of heterogeneity in previous studies examining this question, 4) determine the best therapy for patients with chronic pain, and 5) evaluate the most effective treatment for opioid addiction. We anticipate chronic pain to be an important predictor of continued opioid abuse such that patients with comorbid pain will require careful consideration when managed on OST.
Methods: We systematically reviewed the literature to determine the impact of pain in opioid addiction patients receiving methadone maintenance treatment (MMT). We determined the clinical and inflammatory profile of MMT patients using data from the Genetics of Opioid Addiction (GENOA) research collaborative between the Canadian Addiction Treatment Centres (CATC) and the Population Genomic Program. GENOA is a prospective cohort study aimed to determine the genetic, biological, and psychosocial determinants of treatment prognosis for opioid addiction patients receiving MMT. GENOA recruits patients ≥ 18 years of age meeting the DSM-IV criteria for opioid dependence. All GENOA participants are receiving MMT for the management of opioid addiction. Baseline data from the GENOA pilot study (n=235) were used to evaluate the impact of pain on illict opioid use behaviour and determine the clinical and inflammatory profile of patients with comorbid pain. We explored sources of heterogeneity in previous studies using data from the full-phase GENOA study (n=444), examining the prognostic value of different pain measures for predicting illicit opioid use. We then performed a multiple treatment comparison of all opioid substitution and antagonist therapies in efforts to determine the best intervention for improving treatment outcomes for patients with comorbid pain. We lastly determined the most effective treatment for opioid addiction by performing a network meta-analysis using data from a systematic review of opioid maintenance therapy trials.
Results: Our initial systematic review confirmed a lack of consensus in the literature, whereby some studies suggest pain increases risk for illicit opioid use and other studies suggest pain has no effect on substance use behaviour. Findings from the analysis of GENOA pilot data confirmed chronic pain to be an important predictor of sustained opioid abuse and also showed patients with pain to have elevated Interferon-Gamma. Using data from the GENOA prospective cohort study we determined the Brief Pain Inventory (a commonly used pain measurement in pervious studies) to be highly sensitive with poor prognostic value. Our final reviews propose 1) there is limited evidence to suggest any OST is superior for managing patients with comorbid pain, and 2) heroin and high-dose methadone are the most effective treatments for improving treatment retention. The final systematic review and network meta-analysis in this thesis also highlights a major problem in the treatment of opioid use disorders, primarily the lack of consensus as to what outcomes matter for determining success in patients with addiction.
Conclusion: Patients with comorbid pain and addiction are at high-risk for continued opioid abuse and should be managed closely by clinicians administering OST. Contention in the previous literature likely resulted from the use of pain measurements with poor prognostic value. No OST demonstrated superiority for managing patients with chronic pain. While our findings indicate heroin is the most effective treatment across multiple endpoints, we use this thesis to provide readers with 1) a sense of the feasibility issues associated with heroin administration, 2) a summary of the limitations of this evidence base, and 3) recommendations for how to improve the addiction trials’ design for future research.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Calculation of Corrections to the Random Phase Approximation for an Interacting Electron Gas in the Ground State

contributor:
Vosko, S.H.
Physics

subject: phase, electron, gas, ground state, electron

abstract: This work is concerned with the calculation by means of many-particle perturbation theory of the lowest order corrections to the Random Phase Approximation (RPA) description of an interacting electron gas in its ground state. Expressions in terms of the dynamically screened coulomb interaction are obtained for the electron proper self-energy, the electron momentum distribution function, and the screening function. Techniques, which reduce computational labour to a manageable level, are developed for the practical evaluation of the required corrections. The numerical results are not conclusive but they indicate that when all corrections of the same order (in the screened interaction) are included, the expansion converges sufficiently rapidly that the results are valid in the range of metallic densities.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: DESIGNING A KNOWLEDGE TRANSLATION TOOL FOR THE DEVELOPMENT, APPRAISAL AND REPORTING OF HEALTH SYSTEMS GUIDANCE

title: BETTER GUIDANCE FOR BETTER HEALTH SYSTEMS

contributor:
Brouwers, Melissa
Health Policy

abstract:
Health systems guidance (HSG) can be defined as a set of options presented to policy-makers on how to address a particular health systems issue/challenge (Bosch-Capblanch et al, 2012). However, best strategies for developing HSG and translating it into policy are poorly understood at this time (Lavis et al, 2012). Additionally, there is currently no instrument that has the capacity to discriminate between higher quality HSG from those of lower quality. This thesis begins to address these gaps through three original scientific contributions that use a range of methodological approaches to design a tool that will be used to direct the development, appraisal and reporting of HSG. Taken together, the chapters present three stages conducted in a sequence: Stage 1: A critical interpretive synthesis of the literature to generate a draft list of candidate concepts (items, criteria or domains) for the HSG tool, with their descriptions and a specific set of operational considerations to optimize their use.
Stage 2: Results from a survey conducted across the six World Health Organization (WHO) health regions to evaluate the importance of the candidate concepts, assess the appropriateness of their descriptions, and identify any missing components, in order to generate a beta version of the HSG tool.
Stage 3: Results from a survey conducted across the six WHO health regions to test the usability of the beta version of the HSG tool to determine its feasibility of application and ease of understanding, in order to generate version 1 of the HSG tool.
As a whole, the chapters presented in this thesis provide substantive, methodological and disciplinary contributions to the field of health systems research and in particular, about how to support the production, evaluation and reporting of high quality HSG for the purposes of strengthening health systems in low, middle and high income countries. The core deliverable of this program of research is version one of the HSG tool, the AGREE-HS (Appraisal of Guidelines Research and Evaluation – Health Systems).

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Specificity of Transfer Effects from Video Game Training

contributor:
Watter, Scott
Psychology

abstract: Although the transfer of cognitive performance from video game training is a real possibility, the current literature on the topic is mixed, and prone to a range of confounds. This dissertation developed and tested an improved method for studying transfer of skills from video game training that uses the same game as its own active control. An industrial research collaboration with Canadian video game company Telos International provided a number of commercial games that were able to be modified towards these research goals. In Chapter 2, an initial proof-of-concept study assessed specific near-transfer effects from training on “Membrain”, a 3D spatial memory game, versus training with Sudoku, a traditional number puzzle game. In Chapters 3 and 4, participants played the same commercial video game over several weeks, where the relative proportions of particular easier or harder game elements were manipulated to give different groups of participants more or less experience with particular kinds of game features. In Chapter 3, the “Paint the West” game (a speeded shooting gallery-style game) showed a range of specific transfer effects from increased distractor stimulus similarity, number and crowding within the game, to both improved performance on resisting the influence of nearby distractor stimuli in cognitive tasks, and also to changes in speed/accuracy criterion performance in other speeded tasks. In contrast, in Chapter 4, the “Orphlings” game (a problem-solving spatial puzzle game) showed no convincing transfer effects with a range of working memory and spatial tasks. I suggest that these methods allow for a better estimate of the true effect size of game-specific training improvements, and that the transfer of training effects observed in this research is more directly and reliably attributable to the particular well-controlled feature variations between training groups within the same game context.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: Investigating cognitive control benefits in expert video game players.

contributor:
Humphreys, Karin
Psychology

subject:
cognitive psychology
video game players
cognitive control
executive function

abstract:
As the popularity of video games increases, a growing literature has begun to
examine the association of video game play with cognitive processes. An advantage in
cognitive control ability for video game players (VGPs) compared to nongamers (nVGPs)
has been suggested by a number of recent studies. Miyake et al. (2000) identify three
separable components of cognitive control: ability to shift mental set, updating and
monitoring of working memory, and ability to inhibit automatic responses. In three sets of
experiments, we investigated claims of a benefit in cognitive control for VGPs compared
to nVGPs. Chapter 2 used two task switching paradigms to examine the ability to shift
mental set, finding no difference in cognitive control between VGPs and nVGPs when
baseline differences in response speed were accounted for. In Chapter 3, a series of nback
experiments to investigate working memory demonstrated that VGPs display an
advantage in spatial processing, but not in cognitive control. Chapter 4 assessed group
differences using three measures of inhibitory control: flanker, Stroop, and go no-go
tasks. The results of these experiments suggest that VGPs may rely more on automaticitybased
response strategies than do nVGPs, but no group differences in cognitive control
were evident. Overall, the results of this dissertation dispute a growing literature that
assumes a cognitive control benefit for VGPs compared to nVGPs. Although VGPs
reliably show faster performance on a range of tasks used to assess cognitive control (e.g.,
task switching paradigms), when examined with careful methods, these observed
differences in performance are not attributable to differences in cognitive control ability.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract:
Many people enjoy playing video games, and it is important to understand
whether playing these games is associated with differences in the way we think, or our
ability to complete tasks. Previous studies have claimed that playing video games is
associated with increased control over our ability to selectively respond to our
environment. This dissertation uses a series of experiments to compare the cognitive
control ability of video game players (VGPs), and people who do not play video games
(nVGPs). We tested their ability to switch between different tasks, to hold items in
memory, and to withhold responses. Results of these experiments suggest that although
VGPs may generally respond faster and process spatial information better than nVGPs,
there are no differences in cognitive control between VGPs and nVGPs.


title: THE SELECTIVITY OF UV-LIGHT ACTIVATED METAL OXIDE SEMICONDUCTOR GAS SENSORS MANIFESTED BY TWO COMPETING REDOX PROCESSES

contributor:
Xu, Gu
Materials Science and Engineering

subject:
gas sensor
UV light
selectivity
reaction mechanism
adsorbed oxygen

abstract:
The selectivity mechanism of the UV-light activated metal oxide semiconductor (MOS) gas sensors was studied. A reaction model based on two competing redox processes was presented to solve the selectivity problem. A concept named dynamic equilibrium of adsorbed oxygen concentration was brought about in this model and two reaction
responses were discussed: (1) when most of the MOS surface is adsorbed with oxygen, the resistance of the MOS gas sensor will decrease upon the injection of reducing agents (RAs); (2) when most of the MOS surface is not adsorbed with oxygen, the resistance of the MOS gas sensor will increase upon the injection of RAs. Finally, experiments were conducted on ZnO MOS gas sensors to prove the proposed hypothesis of the reaction mechanism.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: THERMALLY INDUCED POLYMER DEFORMATION FOR ADAPTIVE OPTICS

contributor:
Kitai, Adrian
Materials Science and Engineering

subject:
polymer
luminescent particles movement
lens
concentrator

abstract:
Research on novel solar tracking methods using two polymer-based approaches was conducted. The first design for a solar tracking system with luminescent particles moving along polymer coatings is reported to provide the localized absorption of sunlight by phosphors which can follow the sun and hence provides a higher light intensity to be guided to a solar cell with higher efficiency. The second approach for realizing a polymer-based deformable lens on the surface of patterned ITO glass for light concentrating is reported. Both approaches rely on the application of spatially defined heating to a diluted polymer. These experiments were motivated by a) the well-known Rayleigh-Bénard convection flow within a fluid and b) Bénard-Marangoni flow effects concerning the movement of liquid along the surface of the fluid based on a surface tension gradient as a function of temperature.
In the first project, luminescent particles (YAG:Ce) are placed on the surface of a polymer film cast from a hot melt glue stick with a low melting point. When a heating wire 0.5 mm away from the top surface of the polymer film sample is transferred across the polymer, the floating YAG:Ce particles on the polymer surface can be pushed forward. In order to understand the mechanism of the particle movement, a laser-based measuring method was developed to view the surface profile of the melting polymer in situ. The melted glue stick polymer is observed to form a valley-like surface cross section that is able to transport YAG:Ce powder particles much like a surfer is carried forward on a wave. In the second project, a 0.25 mm thick polystyrene polymer containing a toluene solvent is cast on an ITO coated glass substrate with ITO stripe widths of 2, 6, and 10 mm. The heating source comprised of the ITO stripe can produce spatially selective heat when electric current is applied to thermally deform the cast polymer/solvent layer (polystyrene) on the substrate surface. After the deformation is complete an LED light source is used to determine the light concentration properties of the thermally formed lenses. The ITO stripe surface temperature profile was measured with a thermocouple and modelled with COMSOL Multiphysics software. The vaporization weight loss of solvent was also determined.
The optics of the LED light concentration was modelled by Optics Lab software. When the light emitted from the source passes through the thermally deformed polymer, focusing into two beams occurs in agreement with modelling results.

abstract: Thesis

abstract: Master of Science (MSc)


title: AN FPGA TEST-BED TO DEMONSTRATE DETERMINISTIC GUARANTEED-RATE SERVICES IN THE INTERNET OF THINGS

contributor:
Szymanski, Ted
Electrical and Computer Engineering

subject: Internet of Things

subject: Deterministic Guaranteed- Rate (GR) connections

subject: Software Defined Networking (SDN)

subject: FPGA

subject: Reducing Internet latency to the fiber latency

abstract:
In this thesis, two FPGA testbeds to demonstrate low-latency deterministic Guaranteed-
Rate (GR) connections in packet switched networks such as the Internet of Things are
developed. Each FPGA testbed consists of multiple simple Input Queued (IQ) switches
or routers, interconnected in a given topology to form a forwarding-plane. Each switch
has an associated switch controller with several programmable Lookup- Tables (LUTs).
A Software Defined Networking (SDN) control plane can configure the switch controllers
to establish the GR connections in the forwarding-plane of IP routers or layer- 2 packet
switches. According to a recent paper in the IEEE Transactions on Networking; (1) The
use of very low jitter GR connections can reduce queuing delays to negligible values, so
that the end-to-end delays can be reduced to the  buffer latency. (2) The routers, switches
and links can operate at 100% loads, while simultaneously guaranteeing very low end-
to-end latencies. The goal of the thesis is to evaluate these properties in real hardware
clocked at MegaHertz clock rates. In the  first testbed, a network of 8 simple IQ switches
organized in a linear array is synthesized on an Altera Cyclone IV FPGA. 128 GR traffic flows were routed through the testbed to effectively saturate the switches and links. In
the second testbed, a USA backbone topology with 26 simple IQ switches and 88 links
is synthesized on the FPGA. Over 300 GR traffic flows were routed through the USA network to achieve utilizations exceeding 90%. In both testbeds, packets move through the forwarding plane at a clock rate of 65 MHz, transferring millions of packets per second, and statistics are recorded. Both testbeds con rm that traffic flows achieve deterministic GR service with minimum buffering, where end-to-end delays are effectively reduced to the  fiber latency. These hardware testbeds demonstrate the technical feasibility of achieving deterministic GR services in a packet-switched network such as Internet of Things using simple FPGA switch controllers working with an SDN control plane. The technology also applies to networks of simple optical packet switches with minimal buffering.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: EFFECT OF PRACTICE SCHEDULES ON CONCEPT & CATEGORY LEARNING

contributor:
Kim, Joe
Psychology

subject: learning; memory; applied cognition

abstract:
Interleaving exemplars from different to-be-learned categories, rather than blocking exemplars by category, often enhances the inductive learning of those categories, as measured by learners’ subsequent ability to classify new exemplars from those categories. Majority of the studies on the learning of motor skills, perceptual categories, and mathematics procedures conceptualize the interleaving benefit to be a general learning phenomenon. Results from this dissertation extend the interleaving benefit to the inductive learning of cognitive, rule-based categories (e.g., statistical concepts).
In this dissertation I examine factors that modulate this interleaving benefit, such that interleaving is more or less effective than blocking depending on whether the learning emphasis is on discriminating between categories (discriminative-contrast hypothesis) or encoding commonalities within a category (commonality-abstraction hypothesis), and depending on whether the temporal spacing between exemplars from the same category optimally promote distributed retrieval practice of critical features shared within a category (study-phase retrieval hypothesis). Thus, findings from the current dissertation offer further insight into the boundary conditions of the interleaving benefit.
Consistent with the discriminative-contrast hypothesis, an interleaving benefit was observed when between-category similarity was high and within-category similarity was low, and when there was no temporal spacing between exemplars to disrupt contrast processes critical to between-category comparisons. Consistent with the commonality- abstraction hypothesis, a blocking benefit was observed when between-category similarity was low and within-category similarity was high, and when exemplars were presented three-at-a-time instead of one-at-a-time. Consistent with the study-phase retrieval hypothesis (i.e., introducing spacing between exemplars engages retrieval processes that enhance learning), a blocking benefit was observed when there was temporal spacing between exemplars from the same category.
Moreover, the type of categories themselves and learners’ cognitive abilities drove the effects of category learning differently. Findings from the current dissertation begin to demonstrate the interactions between study schedules and perceptual-based categories (artists’ painting styles) and rule-based categories (statistical concepts). For instance, when between-category similarity was low, the interleaving benefit was eliminated for the perceptual-based categories, but no blocking benefit was obtained, contrary to our prediction. This suggests that blocked versus interleaved schedules may be more or less conducive to learning depending on the type of categories. Finally, learners with lower working memory capacities—that is, learners with cognitive limitations related to information processing and integration—benefited from schedules in which exemplars were presented three-at-a-time, and from schedules that were either temporally spaced or interleaved, but having neither or both manipulations produced sub-optimal performance. To conclude, findings from this dissertation clarify when, for whom, and with what kind of categories is interleaving beneficial.

abstract: Dissertation

abstract: Candidate in Philosophy

abstract: Interleaving exemplars from different to-be-learned categories, rather than blocking exemplars by category, often enhances the inductive learning of those categories, as measured by learners’ subsequent ability to classify new exemplars from those categories. I examined the generality of the interleaving benefit and the conditions that make interleaving more or less effective for learning than blocking. Consistent with the hypothesis that interleaving enables between-category comparisons, I demonstrate that the interleaving benefit generalizes to the learning of complex, rule-based categories and across all learners, particularly those with lower cognitive abilities. Conversely, blocking enables within-category comparisons, and thus can be as beneficial as, or even more beneficial than, interleaving under certain conditions—if exemplars from the same category are presented at three-at-a-time rather than one-at-a-time or if the categories are structured such that there is high-within and low-between category similarity. These findings highlight the need to shift focus away from examining which type of schedule— interleaving or blocking—is more effective for category learning to identifying when and why each type of schedule may be more effective.


title: A Logical Basis for Reasoning with Default Rules

contributor:
Maibaum, Thomas S.E.
Lopez Pombo, Carlos G.
Computing and Software

subject:
Logic
Formal Logic
Nonmonotonic Reasoning
Default Reasoning

abstract:
This thesis is an investigation into the foundations of reasoning with default rules as presented by Reiter in his seminal 1980 article: `A Logic for Default Reasoning'.
In being such, it opens up with a critical appraisal of the logical underpinnings of Reiter's presentation of the main elements of reasoning with default rules.
More precisely, following Reiter's presentation, it discusses the concept of a default rule in comparison with that of a rule of inference, the concept of an extension in comparison with that of a theory, and the concept of `being a consequence of' for reasoning with default rules.
Contrary to the commonly perceived view, the argument put forth is that such a context does not provide sensible logical foundation for reasoning with default rules.
As a result, this thesis argues for an alternative interpretation to what is captured by default rules, what is captured by extensions, and what `being a consequence of' for reasoning with default rules amounts to.
In particular, it proposes to treat default rules as premiss-like objects standing for assertions made tentatively, to treat extensions as interpretation structures of a syntactical kind, and to bring the concept of `being a consequence of' for reasoning with default rules into the foreground by formulating a suitable notion of an entailment relation and its ensuing logical system.
Accounting for the fact that in any logical system it is important to have at hand mechanisms for formulating proofs and for structuring large theories, this thesis presents a tableaux based proof calculus for reasoning with default rules and it explores some mappings notions related to the structuring of default presentations, i.e., presentations in the context of reasoning with default rules.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract:
This thesis is an investigation into the foundations of reasoning with default rules as presented by Reiter in his seminal 1980 article: `A Logic for Default Reasoning'.
A first very general problem definition for this Ph.D. thesis is raised by the following question: Can reasoning with default rules, as presented in Reiter's seminal 1980 article: `A Logic for Default Reasoning', be understood as a logic for non-monotonic reasoning?
This thesis presents a rationale for the formulation of such a question and a possible answer for it.
On the more technical side, this thesis presents a proof calculus for a particular formulation of a logic for reasoning with default rules, as well as some mapping concepts for structuring presentations defined on this logic.


title: Hydrostatic Drive System Design

contributor:
Malherbe, M. C.
Mechanical Engineering

subject: hydrostatic drive, Land and Doig's method, Branch and Bound Mixed Integer Prgoramming, Integer Programming, Gomory method

abstract:
 A solution to an industrial problem of designing a hydrostatic drive system for logging vehicles is presented. A computer program using Land and Doig's method of Branch and Bound Mixed Integer Programming is used to obtain an optimal solution to the problem. A comprehensive users guide to allow the use of the program by unsophisticated users is provided.

 An attempted alternate method of solution using the
Gomory method of Integer Programming is presented and
reasons for its failure discussed.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: MODELLING OF PARTICLE COARSENING AND PRECIPITATION FREE ZONES

contributor:
Hoyt, Jeffrey J.
Materials Science and Engineering

subject:
particle coarsening
precipitation free zone
modelling

abstract:
Starting with the Mean Field Method (MFM) and Boundary Element Method (BEM), we investigate a mathematical model based on these two methods for studying particle-coarsening process in alloys. With MFM, second-phase particles are considered to be merged into bulk matrix, which greatly simplifies computation. However, the Mean-Field model itself is limited to a system with extremely small volume fractions of second phase. By combining BEM with MFM, this mathematical model shows the influence of second phase in particle-coarsening process. Our primary work demonstrates the robustness and capability of this model. This model is however limited to particle coarsening that is far away from grain boundaries.

In this dissertation, we successfully extend the model to particle coarsening near grain boundaries. A major improvement made to the previous mathematical model is based on solute atoms conservation and diffusion theory. The capability and validity of the novel model is demonstrated by a binary alloy system. The simulation results are shown to quantitatively reproduce the essential features of particle coarsening near grain boundaries in certain alloys: a) precipitation Free Zones (PFZs) form near grain boundaries, b) the width of PFZs is proportional to square root of time, c) particles at the edge of PFZs are larger than those inside the grain.

This novel model is shown to be well suited in describing particle coarsening near grain boundaries. On the other hand, it proves the credibility of the theories built in our mathematical model, i.e., the formation of PFZs near grain boundaries is caused by diffusion of solute atoms.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Investigations of Albedo Over Snow

contributor:
Rouse, W.R.
Geography

subject: snow surface albedo, Petzold, polar, sub-polar, continental stations

abstract:
 The importance of snow surface albedo has been recorded by many authors. Techniques have been attempted with less than favorable results by D.E. Petzold (1977). This paper investigates the methods proposed by Petzold and offers alternative methods of albedo estimations using polar, sub-polar and continental stations as data
sources.

abstract: Thesis

abstract: Bachelor of Arts (BA)


title: Solubility of Nitrogen in Liquid Iron Alloys

contributor:
McLean, A.
Metallurgy

subject: Nitrogen in Liquid Iron Alloys, Iron Alloys, iron-carbon, iron-aluminium, pure liquid iron, Metallic Solutions, Metallic formations, Thermodynamic internactions, solubility

abstract: An investigation has been made concerning the solubility of nitrogen in pure liquid iron, iron-carbon and ironaluminium alloys. A technique involving levitation melting and a rapid quench device has been used. The experimental data obtained have been expressed in terms of the interaction coefficients proposed by Wagner and Lupis and Elliott. The data have also been used to test the formalisms developed recently by Darken and Chipman. A simple model for liquid metal solutions in which the solutes may be considered "interstitial" has been developed and tested using the results of the present study and published data for a number of ternary solutions

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Shoreline of Lake Huron, From Grand Bend to Port Franks, And The Problems At the Mouth of The Ausable River

title: The Lake Huron Shoreline, Grand Bend to Port Franks

contributor:
McCann, S. B.
Geography

subject: LAke Huron, Ontario Shoreline, Ontario, recreational, water levels, rising water levels, Great Lakes, beach erosion, Grand Bend, Port Franks, Ausable River, lagoon, Kettle  Point

abstract:
 The Ontario shoreline of Lake Huron is one of the most populated areas, with reference to recreational purposes, in Ontario. However, with the rising water levels of the Great Lakes during 1972 and again in 1973, serious problems of beach erosion have resulted, particularly in the area of Grand Bend and Port Franks. This loss of sand has threatened cottages built on the dunes in addition to destroying breakwalls, steps, and boat launching ramps along the beach. It was with the idea of learning more about the beach, and possibly suggesting some methods of beach protection, that the research for this thesis was initiated. During the course of study, the author also became interested in the Ausable River and the associated flooding and erosion problems, with reference to past, present, and future attempts to solve or at least alleviate these difficulties. Thus, one section of the thesis is concerned with the Ausable River alone.

 The beach studied is actually the culmination of a series of raised beaches, formed during higher post-glacial lake stages. These raised beaches formed a bar separating the now non-existent Ausable Bay from Lake Huron, forming a lagoon eastward of the beach. This bar extends from Grand Bend, in a southwest direction, and culminates at Kettle Point. However, for the purposes of this thesis, that section between Grand Bend and Port Franks received the greatest amount of concentrated study. Over the years, the lagoon, formed by the growth of the bar has silted up, and is now drained for agricultural purposes.

 The modern beach was observed during the summer of 1972. This involved, profiling of a portion of the shore and offshore topography, procuring beach samples for later analysis, the use of sequential air photographs for observing changes over time, and the analysis of wind and wave data, along with many conversations with local residents and personal observations.

 The subsequent study of the above factors revealed several major conclusions regarding the beach. First, that it has good natural protection against erosion due to the abundance of sand s tored by the dunes. Second, the beach appears to be in an equilibrium state, however as lake levels fluctuate, so must the beach level, thus destroying the equilibrium for a period of time. With the lowering of the water level, the beach will become wider, exposing sand to the onshore winds, which will in turn rebuild the dunes with the blowing sand. Finally, because of the prximity of man-made structures to the beach, on the unstable dunes, some method of stabilizing the beach is necessary. That suggested is a groin system, designed and constructed by the local authorities. This would help prevent erosion and would eliminate the often vain and possibly dangerous, (to the natural environment), attempts by individuals to halt erosion.

 This is by no means a complete study of the area and its problems. Further consideration should be given to proposals which have been presented to the local conservation authority, and which were designed to alleviate some of these problems, particularly at Port Franks. The suggestions made here should also be given further thought. In addition to these practical problems, the actual growth of the original bar would provide an interesting subject for study.

abstract: Thesis

abstract: Bachelor of Arts (BA)


title: A lot to learn: internationally-trained social workers repeating graduate degrees at Ontario universities

contributor:
Baker Collins, Stephanie
Social Work

subject:
internationally trained
social workers
credential devaluation
post-secondary education
regulation

abstract:
The purpose of this study is to examine the phenomenon of institutional credential devaluation and the impacts on internationally-trained social workers in Canada. International social workers are recruited to immigrate to Canada based on their credentials and experience but some discover after immigrating that their qualifications are devalued which limits or prohibits their ability to engage in professional practice. This experience is recognized within the literature in other professions; however, there has been insufficient attention given to it within social work itself and to the various stakeholders involved.
Using critical theory and interpretative phenomenological analysis, semi-structured interviews were conducted with internationally-trained social workers to gain insight into their experiences of devaluation and graduate degree repetition in Ontario universities. Extensive exploration of the institutional stakeholders in credential assessment, the field of social work and universities was also undertaken and provides systemic context to the experiences of international social workers.
While internationally-trained social workers have high views of Canada prior to immigrating, these perspectives change upon encountering systemic devaluation and discrimination post-immigration. They describe confusion, frustration and powerlessness as they navigate through social work systems in seeking to gain recognition of their credentials in order to practice. When they eventually decide to return to Ontario universities to obtain the recognition they need/deserve, they experience continued devaluation. Instead of identifying different or better social work education in Ontario, they describe repetition of what they learned in their countries of origin, raising questions about the similarities and differences in international social work education. The personal costs and psychological impacts of these experiences are shared by the participants. The practices of social work and post-secondary institutions in creating systemic barriers to internationally-trained social workers are examined with recommendations for further research and policy and practice changes that will lead to greater justice and equity.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Nutrition, Aging and Reproduction In The House Fly, Musca Domestica L., And The Histology and Histochemistry of the Related Changes in the Ovaries and Fatbodies

contributor:
Davies, D. M.
Biology

subject: Nutrion, aging, oogenesis, adult house flies, flies, diets, ovaries, fatbodies, eggs, offsprings, sugar water, milk, ovarian cycles

abstract: <p> This research was designed to gain a better understanding of the relationships between nutrition, aging and oogenesis. Cohorts of 1800 inbrod, adult house flies were maintained on various undefined and chemically defined diets. From these flies samples for histology were removed periodically, and the rest were analyzed for their survival and their ability to develop and lay viable eggs. The survival of the females was more affected by nutrition and other factors than that of the males. In females fed sugar water, oogenesis was arrested at an early stage, but survival was lower than on a milk diet. From adult emergence until the completion of one or more ovarian cycles, the larval and adult fatbodies and the ovary were compared as to their histology, histochemistry and cytology.

abstract: Thesis

abstract: Master of Science (MSc)


title: Topics on the Nucleon-Nucleon Interaction

contributor:
Nogami, Y.
Physics

subject: nucleon-nucleon, phase-equivalent, off shell, on shell, phase-equivalent, separable potentials, proton proton, bremsstrahlung

abstract:
 Some aspects of the nucleon-nucleon interaction are
investigated. Phase-equivalent families of rank-two separable
potentials are derived by inverting the on- shell phaseshifts.
The off-shell properties of these potentials are
examined and shown to be well behaved. These and additiona l
pairs of phase-equivalent local and separable potentials
are included in a proton-proton bremsstrahlung calculation.
In particular, the off-shell dependence of the cross sections
is shown to be small.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Some Acetylene Complexes of Nickel, Palladium and Platinum

contributor:
Maitlis, P. M.
Chemistry

subject:
acetylene complex
nickel
palladium
platinum
infrared spectrum
nuclear magnetic resonance system

abstract: The work describes the preparation of some acetylene complexes of nickel, palladium and platinum. The structure of and the bonding in these complexes is discussed in the light of their infrared and nuclear magnetic resonance spectra. Some reactions of the complexes are described.

abstract: Thesis

abstract: Master of Science (MSc)


title: A Study of the Quadrupolar Interaction in Vanadium-Oxygen Compounds

contributor:
Stager, C. V.
Physics

subject:
vanadium
vanadium pentoxide
charge distribution
nuclear magnetic resonance
point multipole model
covalent model

abstract: The quadrupolar interaction in sodium orthovanadate dodecahydrate, calcium orthovanadate, vanadinite, descloizite, zirconium divanadate, cadmium divanadate, potassium metavanadate and vanadium pentoxide, was studied by nuclear magnetic resonance. The v51 quadrupole coupling constants in these compounds show a strong correlation with the distortion of the tetrahedral symmetry around the vanadium ion. Vanadium pentoxide is an exception and shows a surprisingly small coupling constant. The point multipole model was found to be inadequate for the calculations of the electric field gradients in these compounds. A covalent model provides an explanation of the small magnitude of the coupling constant of vanadium pentoxide. However, because of the numbers of approximations in this model, only a qualitative correlation with the experimental results was achieved. In addition, the chemical shift tensor of the v51 resonance line in a single crystal of vanadium pentoxide was measured to be very large. This result was correlated with a large Van Vleck term in the magnetic susceptibility of vanadium pentoxide.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Development of the exercise and state body image model: Examining changes in self-efficacy, physical self-perceptions, and affect as mechanisms by which acute exercise improves state body image

contributor:
Martin Ginis, Kathleen A.
Kinesiology

subject:
state body image
acute exercise
self-efficacy
physical self-perceptions
affect

abstract:
The primary purpose of this study was to determine if changes in physical self-efficacy, physical self-perceptions, and affect (including enjoyment) are mechanisms by which a single bout of exercise improves state body image. A secondary purpose was to identify how long exercise-related improvements in state body image are sustained post-exercise. Sixty women with body image dissatisfaction were randomized to either an exercise or control condition. Participants in the exercise condition completed a 30 minute moderate-to-vigorous intensity workout on a stationary bike. Women in the control condition read for the same duration. Before and immediately, 10-minutes and 20-minutes after (post-0, post-10, post-20) the exercise/control manipulations, participants completed measures of state body image, aerobic self-efficacy, physical self-perceptions and affect (including enjoyment). PROCESS macro was used to test mediation models, and a repeated measures mixed ANCOVA, followed by a univariate ANCOVA was used to test how long state body image improvements were sustained.
There was a significant indirect effect of increases in strength self-perceptions on state body image improvements from pre- to post-0 (95% C.I. =.07 - .52, κ2=.16, abps=.31), post-10 (95% C.I.=.05 - .50, κ2=.16, abps=.30) and post-20 minutes (95% C.I. = .10 - .55, κ2 =.16, abps =.33), as well as a significant indirect effect of decreases in tiredness (i.e., increases in the energetic arousal dimension) on state body image improvements from pre- to post-10 (95% C.I. =.22 – 1.14, κ2=.30, abps=.77). Exercise-related state body image improvements were sustained 20 minutes after exercise.
The present findings suggest that a bout of exercise improves state body image through increases in strength self-perceptions and energetic arousal and these effects lasted up to 20 minutes. This is the first study to design and empirically test a model to account for the effects of exercise on state body image, and provides important theoretical and practical implications.

abstract: Thesis

abstract: Master of Science (MSc)


title: Biomechanics of C. elegans as probed by micropipette deflection

title: Biomechanics of C. elegans

contributor:
Dalnoki-Veress, Kari
Physics and Astronomy

subject: Biomechanics Microswimming

abstract: In this PhD thesis, a novel experimental technique has been implemented to study the variables controlling the undulatory locomotion of a tiny worm. Well known for its elegant slithering motion and simple biology, the millimetre-sized nematode Caenorhabditis elegans was chosen to serve as a model organism for our work. The emphasis of this thesis, as embodied by three separate research projects, has been to study the passive and active biomechanical properties of C. elegans, as well as to investigate inter-worm interactions. Micropipette deflection has been used to directly probe forces in a time-resolved manner and with high dynamic resolution. The viscoelastic material properties of C. elegans were explored on a biologically and structurally relevant length scale, and the elastic properties of the body were quantified. Furthermore, the soft tissue was found to behave as a shear-thinning fluid: a non-Newtonian property that has interesting implications on the undulatory locomotion strategy of the nematode. Micropipette deflection furthermore allowed for measurements of the active swimming dynamics of C. elegans. Our experiments quantified the drag coefficients of the tiny worm as well as the viscous forces present in its swimming motion. Swimming experiments were performed in a normal buffer solution, in the confinement of solid boundaries, as well as in fluids with increased viscosities, and the dynamics of the gait modulating worm was investigated. Finally, the binary interactions between two swimming nematodes were studied, utilizing the high micromechanical control provided by the micropipette-based technique. Our findings provide new insight into the physics of undulatory locomotion and active materials in general.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Cumulative Yields from the 14-MeV Neutron Fission of 238U

contributor:
Tomlinson, R. H.
Chemistry

subject:
neutron fission
neutron yield
isotopes
mass spectrometry

abstract:
Isotopic abundances of the elements xenon, krypton, and cesium
formed in the 14-Mev neutron fission of 238U have been measured using the mass-spectrometric method. The relative yields of some isotopes of krypton, strontium, zirconium, molybdenum, ruthenium, iodine, xenon, barium, cerium and neodymium were measured using a Ge(Li) detector. The ratios were normalized through isobaric nuclides, and absolute yields were obtained by normalizing the sum of the heavy-mass yields
to 100%. A semi-empirical method has been developed for constructing neutron yield curves. Such a curve was used to obtain a primary-yield curve from the cumulative yields reported here. The results indicate that considerable structure might exist in the primary-yield curve at the higher excitation energy.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Generation of Small Scale Relief Features of Eroded Limestone: A Study of Erosional Scallops

contributor:
Ford, Derek C.
Geography

subject: Eroded Limestone, Erosional, erosion, scallops, snow surfaces, karst surface, subterranean drainage, hydrologic, fossil, velocity, quantity, speleologists

abstract: Proposed theories concerning the nature and mode of formation of limestone scallops are examined. Some progress is made toward a purely theoretical understanding. Scallop formation is simulated by generation on blocks of Plaster of Paris in a laboratory flume under known and controlled conditions and the relationships between the resulting features, the generating conditions and the base material examined. Field Evidence both confirms these relationships and reveals other unsuspected factors. The similarity between these features and others found on ablating snow surfaces is investigated and the same laws found to apply.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: THE SCALE SIZE AND DYNAMICAL EVOLUTION OF STAR CLUSTERS IN TIDAL FIELDS

contributor:
Harris, William
Sills, Alison
Physics and Astronomy

subject:
Globular Cluster
Milky Way
Giant Elliptical Galaxies
Tidal Field
Tidal Radius

abstract:
Globular clusters are found in the halos of all types of galaxies, and have been shown to play major roles in the formation of stars and galaxies. The purpose of this thesis is to advance our level of understanding of the dynamical evolution of globular clusters through N-body simulations of clusters with a range of circular, eccentric, and inclined orbits. Theoretical studies have historically assumed that globular clusters experience a static tidal field, however the orbits of globular clusters are all non-circular and the tidal field of most galaxies is not symmetric. Understanding how clusters evolve in realistic potentials allows for them to be used to constrain the formation, merger history, and evolution of a host galaxy and even map out the current size, shape, and strength of a galaxy's gravitational field.

We find that dense and compact clusters evolve as if they are in isolation, despite being subject to a non-static tidal field. For larger clusters, tidal shocks and heating inject energy into the cluster and significantly alter its evolution compared to previous studies. We describe how a non-static field alters the mass loss rate and relaxation time of a cluster, and propose methods for calculating a cluster's size and orbit.

We then apply our work to clusters in the giant galaxies M87, NGC 1399, and NGC 5128. We consider each cluster population to be a collection of metal poor and metal rich clusters and generate models with a range of orbital distributions. From our models we constrain the orbital anisotropy profile of each galaxy, place constraints on their formation and merger histories, and explore the effects of nearby galaxies on cluster evolution.

By advancing studies of globular cluster evolution to include the effects of a non-static tidal field, we have made an important step towards accurately modelling globular clusters from birth to dissolution. Our work opens the door for globular clusters to be used as tools to study galaxy formation, evolution, and structure. Future studies will explore how galaxy formation and growth via the hierarchical merger of smaller galaxies will affect cluster evolution.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: A System Approach to Fission-Fusion Symbiosis

contributor:
Harms, A. A.
Engineering Physics

subject: Tritium production, coupling, fission reactor, fertile conversion, fusion blanket, fuel dynamics, power output, efficiency, cost of a sybiotic, self contained power station, thorium cycle

abstract:
 Three symbiotic systems are considered. These include the
possibility of coupling the tritium production in a fission reactor
with the fertile conversion in a fusion blanket. Equations for the
fuel dynamics, power output, efficiency and costs of a symbiotic, selfcontained power station are developed and evaluated for a specific,
1500 MWe fission reactor operating on a thorium cycle and some fusion
parameters. It is concluded that a system using the tritium produced
in a fission reactor has lower costs and increased power output when
compared to an alternate system.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: A Study of Sporulation and Spore Germination in Two-Spored Yeasts

contributor:
Miller, J. J.
Biology

subject:
sporulation
yeast
nuclear division
germination
Finder Slide technique
electron microscopy

abstract: Nuclear divisions during sporulation of 15 predominantly two-spored and 2 predominantly four-spored yeasts were followed by Giemsa staining and light microscopy. The number of nuclei present per ascus was related to the presence or absence of conjugation at the time of germination of the spores. Plating experiments and a modification of the Finder Slide technique were used to determine whether progeny cells that developed from single spores of 2 two-spored and one four-spored strain could sporulate. The ploidy of these yeasts at different stages of their life cycles was estimated by DNA extractions. The spores of the two-spored yeasts were very difficult to separate following removal of their ascus walls, and electron microscopy was employed in an attempt to account for this.

abstract: Thesis

abstract: Master of Science (MSc)


title: Incorporating Temporal Heterogeneity in Hidden Markov Models For Animal Movement

contributor:
Bolker, Benjamin
Statistics

subject: Hidden Markov

abstract:
Clustering time-series data into discrete groups can improve prediction as well as providing
insight into the nature of underlying, unobservable states of the system. However,
temporal heterogeneity and autocorrelation (persistence) in group occupancy
can obscure such signals. We use latent-state and hidden Markov models (HMMs),
two standard clustering techniques, to model high-resolution hourly movement data
from Florida panthers. Allowing for temporal heterogeneity in transition probabilities,
a straightforward but rarely explored model extension, resolves previous HMM
modeling issues and clarifies the behavioural patterns of panthers.

abstract: Thesis

abstract: Master of Science (MSc)


title: An Investigation of Lithium Distribution in Certain Precambrian Iron Formations

contributor:
Shaw, D.M.
Geology

subject: precambrian, iron, material, lithium

abstract:
 Precambrian iron formations from N.W. Ontario and Melville Peninsula, District of Franklin, were analyzed for Li and major
elements. The N.W. Ontario samples contain little Li (0.46 to
5.88 ppm) but high percentages of mafic silicates (20 to 50%).
The Melville Peninsula samples show the opposite, having higher
Li (1.65 to 58.2 ppm) and lower silicate material (0.6 to 25.0%).

 Results from acetic acid leaching experiments show that part of the Li in the Melville irons may be removed, indicating Li to be present both by absorption and substitution.

 The higher Li abundances in the Melville Peninsula rocks may be attributed to the effect of later intrusive granites.

abstract: Thesis

abstract: Bachelor of Science (BSc)


title: Suburban Affiliation to Urban Centres as Measured By Newspaper Circulation and Other Indicators (Case Study: Burlington, Ontario)

contributor:
Martin, S.
Geography

subject: urban, affiliation, interaction, Burlington, residents

abstract:
 This research paper addresses the question of the urban affiliation of a suburban population. Social survey data on spatial interaction are used to determine the affiliation of Burlington residents with the Hamilton-Wentworth region and Metropolitan Toronto. A secondary objective is to study the role of urban newspaper circulation in the suburban community in relation to the other variables for measuring urban affiliation. Specific attention is given to spatial variations in urban affiliation for different sub-areas within Burlington.

 The results show Burlington residents to be more affiliated with Hamilton-Wentworth than Metropolitan Toronto. However, within Burlington, sectoral differences in affiliation emerge. The older areas of Burlington have a strong affiliation to Hamilton-Wentworth; the later developed areas have equal levels of affilation with both urban centres. Newspaper circulation, emerges as a significant indicator of urban affiliation, but is a weaker measure than several other indicators (e.g. number of trips to urban centres and number of telephone calls to urban centres). Reasons for this are postulated in the analysis and in the conclusions.

abstract: Thesis

abstract: Candidate in Philosophy


title: Structured Styrenic Polymer Microspheres by Precipitation Polymerization

contributor:
Stover, Harald
Chemistry

subject:
precipitation polymeriztion
micropsheres
core/shell
thermal imprinting

abstract: Precipitation polymerization is a unique method that produces narrow-disperse, uniform polymer particles with clean surfaces. In this research, internally structured poly(divinylbenzene-co-chloromethylstyrene) polymer microspheres were prepared by thermal imprinting precipitation polymerization. The influence of thermal profiles and the monomer/crosslinker feed ratio on the resulting core-shell microspheres were explored by optical and transmission electron microscopy, and potential route to extend this technique to other polymer system was discussed. Further surface functionalization of this type of particles was demonstrated by substitution of chlorine with cysteine, a good and hydrophilic nucleophile. Narrow-disperse, hydrophilic particles may in future serve as components of synthetic extracellular matrices used in exploring cell-matrix interactions in a 3D context.

abstract: Thesis

abstract: Master of Science (MSc)


title: Petrography of Middle Triassic Cross-Bedded Sandstones in Northeastern British Columbia

contributor:
Middleton, G.V.
Geology

subject: petrography, triassic, sandstones, cross-bedded

abstract: An attempt is made to determine compositional and textural trends in the direction of sediment transport in middle Triassic cross-bedded sandstone samples collected from northeastern British Columbia. Petrographic measurements of textural and compositional properties were made and a multiple regression analysis was performed on 27 samples collected from a particular lithological unit. The general petrographic aspects of middle Triassic sandstones were investigated and are discussed.

abstract: Thesis

abstract: Master of Science (MSc)


title: Depositional History and Processes at Burford, Ontario

contributor:
Ford, D.C.
Geography

subject: facies, sediment, soil, sand, lenses

abstract:
 Sediment samples were taken from the exposed facies of two quarries north of Burford Ontario. The samples were then dry sieved and the results were plotted as frequency histograms to show the type and quantity of sediment present. Moreover, measurements of soil tongues, sand lenses and strata depths were recorded to provide a comprehensive understanding of the depositional history and processes.

 The above research was then combined with the present day comprehension of the depositional history of southern Ontario. The conclusions reached in this paper are useful, as they contribute and improve the understanding of the depositional history of southern Ontario.

abstract: Thesis

abstract: Candidate in Philosophy


title: Targeting Respiratory Syncytial Virus Using a Chimeric Phosphoprotein Mimetic

contributor: Medical Sciences (Molecular Virology and Immunology Program)

subject: Respiratory Syncytial Virus, Phosphoprotein

abstract: Respiratory syncytial virus (RSV) is a pathogen associated with lower respiratory tract infection, and is a common cause of infant hospitalization worldwide. Despite efforts to create safe and cost-effective RSV therapeutics, there remains no vaccine, and antiviral drugs have been developed with limited success. Among the 11 proteins coded by the negative-sense single-stranded RNA genome of RSV, the phosphoprotein (P) and nucleoprotein (N) aid in the formation of an RNA-dependent RNA polymerase (RdRp) complex, which is essential for RSV virulence. The specificities of the N-P binding interaction have been researched extensively, which has provided researchers with a novel target for an RSV therapeutic. In this study, a recombinant peptide mimetic (P220-241) containing the final 21 C-terminal amino acids of RSV P fused to Maltose-Binding Protein (MBP), and a cell-penetrating peptide (CPP), was purified for the purpose of targeting this interaction. In addition to successfully entering cells, the peptide was shown to inhibit both RSV subtype A and subtype B infection in vitro, with a percent inhibition (PI) of infection as high as 95% at 20 μM. Additionally, P220-241 did not inhibit infection of parainfluenza virus type 2 (PIV-2), indicating this inhibition was not an artifact of the peptide acting as a pathogen-associated molecular pattern (PAMP). A series of three different assays demonstrated that P220-241 does not appear to have any cytotoxic effects in vitro. Finally, using both glutathione S-transferase (GST) pull-downs and in vitro immunoprecipitations, we demonstrated that P220-241 is able to bind the N protein, while also preventing binding of full-length P protein. Taken together, this study provides the framework for a novel method of targeting RSV protein-protein interactions using chimeric cell-penetrating peptide mimetics.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Implications of Gauging Lepton Flavour Symmetries for Dark Matter and Neutrino Masses

contributor:
Yavin, Itay
Physics and Astronomy

subject: Particle Physics, Dark Matter, Neutrinos

abstract:
The Standard Model of particle physics is a phenomenologically successful description of the strong, weak, and electromagnetic interactions at all currently accessible energy scales with few exceptions \cite{Agashe:2014kda}. The notable deficiencies of the Standard Model are its inability to explain the matter anti-matter asymmetry, the existence of neutrino oscillations \cite{Fukuda:1998mi,Ahmad:2002jz}, the anomalous magnetic moment of the muon \cite{Bennett:2006fi,Hagiwara:2011af}, and its failure to provide a suitable candidate for the gravitationally observed dark matter \citep{Dolgov:1995np}.

We explore an extension of the Standard Model that introduces a new gauge symmetry $L_\mu-L_\tau$ along with three right-handed neutrinos, and a symmetry breaking scalar field. The inclusion of right-handed neutrinos are motivated by the aforementioned neutrino oscillation data while the scalar field is motivated by cosmological bounds on a new $Z'$.

We attempt to fit our model to the observed neutrino mass textures in the see-saw limit. Despite having a Lagrangian density with three Yukawa couplings, and four right-handed mass parameters we found the left handed neutrino mass matrix was controlled by only four independent quantities. We were attempting to fit to a set of five measured parameters $\{ \Delta m_{12}^2,\Delta m_{13}^2,\theta_{12},\theta_{23},\theta_{13} \}$. This was found to be impossible with our proposed model. Higher dimensional operators were introduced to allow the model to generate neutrino textures that agree with experiment.

Our first minimal model was able to reproduce the correct neutrino textures with the exception of one of either $\theta_{13}$ or $\theta_{12}$ the disagreements was at the level of $25\%$.  We found that our model was able to fit to the central value of neutrino data after the introduction of various combinations of dimension-five  operators. The parametric dependence of these solutions were found to be incompatible with the $Z'$ as a progenitor of dark matter scenario proposed by Shuve and Yavin \cite{Shuve:2014doa}. The $Z'$ progenitor scenario and the see-saw mechanism seem to be distinct entities in the sense that for the former to be viable the dark matter candidate cannot play a significant role in the generation of neutrino textures.

abstract: Thesis

abstract: Master of Science (MSc)


title: Energy Fair Cloud Server Scheduling in Mobile Computation Offloading

contributor:
Zhao, Dongmei
Todd, Terence D.
Electrical and Computer Engineering

abstract:
This thesis considers the issue of energy fairness in mobile computation offloading. In computation offloading, mobile users reduce their energy consumption by executing jobs on a remote cloud server, rather than processing the jobs locally. This can result in energy unfairness however, when the processed jobs are subject to hard deadline constraints.

In this thesis we consider how energy unfairness can be compensated for, by smart scheduling at the cloud server. We first derive an optimum offline scheduler using an integer linear program (ILP) that uses a min-max energy objective and preemptive cloud server scheduling. We then introduce several online scheduling algorithms. The first one is referred to as First-Generated-First-Scheduled (FGFS), where jobs that are generated earlier are given cloud server priority. A modified version, referred to as γ-Ratio Accepted FGFS (γ-FGFS) is proposed, where the acceptance of job submission is subject to an energy threshold test. A version of this algorithm, γ-Ratio Accepted Earliest Deadline First (γ-EDF), is considered that uses earliest deadline first (EDF) scheduling to test for job feasibility.

We also include comparisons using an analytic model that shows the performance possible when the system uses optimum open loop job submission (OLJS) with first-come-first-served (FCFS) cloud server scheduling. Various performance results are presented that show the improvements in energy fairness possible with the proposed schedulers.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Public Participation for Major Transportation Studies

subject: public, transportation, participation

abstract:
Abstract Not Provided.
Thesis
Master of Engineering (MEngr)


title: Depression and its determinants in children and adolescents with obesity

title: Depression and its determinants in youth with obesity

contributor:
Morrison, Katherine
Medical Sciences

subject:
Obesity
Pediatrics
Depression
Mental Health
children and adolescents
inflammation
BDNF
leptin
body fat
anthropometric
socio-demographic factors
HPA axis
clinical research

abstract:
There is increasing recognition of the relationship between depression and obesity in the pediatric population and recently, there has been a focus on inflammation as a potential link. Both conditions are considered to be pro-inflammatory states, and certain inflammatory markers are linked to depression in obese adults and vice versa. Leptin has also been implicated in depression as a potential mediator between inflammation and depression. Brain derived neurotrophic factor (BDNF), which is associated with depression and obesity, is influenced by inflammation and leptin in animal models as well.
Few studies have examined the interactions between depression, adiposity, and biological markers in obese youth and therefore, our objective was to explore the determinants of depression in obese youth in a clinical setting. We studied 244 youth aged 8-17 years (125 girls, 119 boys) at the time of entry to a weight management program, as part of a prospective, longitudinal study. The CES-DC depression-screening tool was used to assess depressive symptoms, and a participant was classified as having high depressive symptoms if the CES-DC score ≥15 or taking antidepressants. Questionnaires assessed socio-demographic factors and puberty while adiposity was measured using dual-energy X-ray absorptiometry (DXA). Inflammatory markers (IL-6, TNFα, CRP, IL-10), leptin, and BDNF were quantified by immunoassays.
 Of the 244 participants, 8 were on antidepressants and 88 (36.4%) met the criteria for high depressive symptoms. We confirmed previous findings that household income and body fat were important determinants of depressive symptoms. However for the first time, it was identified that leptin levels predicted CES-DC score independent of body fat. Neither inflammatory markers nor BDNF were significantly related to depression scores. Our findings suggest that leptin may mediate the relationship of adiposity and depression but it is uncertain if this is related to direct action or to the phenomenon of leptin resistance.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Obesity has a significant impact on depression in children and adolescents. Inflammation – the body’s response to injury – is measured through markers in the blood and leptin – the marker of body fat – have shown to be related to depression. Research indicates that depression influences these factors to act on obesity. However, research on the interactions of biological and socio-demographic factors with depression in youth with obesity is lacking. Therefore, our objective was to explore the impact of these factors on depression in obese youth entering into a weight management program. Using a depression-screening tool, we studied 244 youth under 18 years and confirmed that household income and body fat were important factors of depression. However for the first time, we found leptin influenced depression regardless of the amount of fat present suggesting that depression acts on obesity through leptin but it is uncertain how this occurs and further research is warranted.


title: Virtual Mereology: Power, Affect, and Relation in Spinoza's 'Ethics'

contributor:
Arthur, Richard T. W.
Sassen, Brigitte
Johnstone, Mark
Philosophy

subject: Spinoza, Power, Affect, Mereology

abstract: This dissertation offers a novel interpretation of the metaphysical system Spinoza presents in his Ethics by considering it entirely in terms of power, affectivity and part/whole relations.  I begin by arguing that the central concern of the Ethics is what I term ‘the problem of passivity’.  Namely, if as part of nature, we are necessarily always subject to passive emotions, we could seemingly not become active to the point of adequate conception without ceasing to be a part of Nature.  I argue that adequate conception, rather, requires a mereological conception of oneself as part of the whole of Nature.  Since such understanding requires a conception of the whole in which these parts inhere, I explicate Spinoza’s conception of substance as that which enjoys an absolute and infinite power of existence.  Inasmuch as this power of existence necessarily involves a coextensive power to act, I then argue that for Spinoza the whole of Nature is defined in terms of power.  Consequently, the infinite modifications following from eternal substance ought to be considered as powerful parts of this potestative whole.  Individual things are, then, to be defined as dispositional structures manifesting their capacities in interdependent relations.  The thesis comes to explain this by using the Medieval mereological category of a ‘virtual whole’ (i.e. a unique particular power whose parts are inseparable from it, and only differentiated according to their own capacities).  The dissertation concludes with a suggestion for further research on the possibilities that the presented theory of virtual mereology could have in relation to Spinoza’s ethico-political philosophy.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: The role of basophils in the late asthmatic response and the effect of alarmin cytokines on basophil pro-inflammatory activity

contributor: Medical Sciences (Division of Physiology/Pharmacology)

abstract: There is emerging evidence that the alarmin cytokines, thymic stromal lymphopoietin (TSLP), interleukin (IL)-25 (IL-25), and IL-33 are critical mediators of T helper cell type-2 (Th2)-driven inflammation in allergic airway disease. Although there is a myriad of data pertaining to the interaction between these alarmins and immune cells, there is still very little known on how alarmin cytokines can influence the activity of basophils in allergic asthma. The overall objectives of this thesis were to examine the involvement of basophils in the late asthmatic response (LAR) of allergic asthma and to determine whether their pro-inflammatory activity is influenced by alarmin cytokines. Initially, we investigated the change in activity and migration of basophils following allergen inhalation in mild allergic asthmatics. We showed that a subset of activated basophils migrate from the bone marrow into peripheral blood and then to the airways during an airway allergen challenge (Chapters 2-5). We found expression of surface activation markers and intracellular Type 2 cytokines was increased after an allergen challenge for up to 24 hours (Chapter 3). Next, we examined the change in expression on basophils of receptors for TSLP, IL-25, and IL-33 following an allergen challenge (Chapters 3 and 4). We reported that basophil surface receptor expression for alarmin cytokines was markedly increased post-allergen challenge within the peripheral blood and airway samples. In addition, we investigated the effect of these alarmin cytokines on basophil activity in vitro, demonstrating that they can directly stimulate basophil activation and Type 2 cytokine intracellular expression, as well as prime eotaxin-induced migration (Chapters 3 and 4). Finally, to explore the pro-inflammatory response of basophils to the airway microenvironment, we examined the effect of airway samples collected post-allergen on basophils in vitro (Chapter 4). We showed that basophil activation and Type 2 cytokine intracellular expression were up-regulated following incubation with 7 hour post-allergen airway samples, and could be inhibited following treatment with a monoclonal antibody (mAb) to the common β-chain (βc) for IL-3/IL-5/granulocyte-macrophage colony-stimulating factor (GM-CSF). The novel work presented herein augments the available evidence that basophils play a role in the LAR of allergic asthma that may be in part mediated by interaction with alarmin cytokines. These observations support the notion that the basophil/alarmin cytokine axis is a potentially important therapeutic target for allergic asthma. Continued investigation is required to determine if blockade of this axis can inhibit or attenuate allergic airway inflammation and bronchoconstriction.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Chronic Pain: A Red Herring or Risk Factor in the Management of Patients Receiving Opioid Substitution Therapy

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
chronic pain
methadone
opioid substitution therapy
opioid agonist treatment
methadone maintenance treatment
opioid addiction
addiction
opioid induced hyperalgesia

abstract:
Background: The consequences of continued opioid abuse among patients treated with opioid substitution therapy (OST) are serious and can result in abnormal cardiovascular function, overdose, and mortality. Conflicting evidence exists that both implicates and refutes the role of chronic non-cancer pain (CNCP) as a major risk factor for continued opioid abuse within the addiction treatment setting. This thesis aims to 1) evaluate the impact of chronic pain on the treatment outcomes of patients with opioid addiction receiving OST, 2) determine whether a clinical or inflammatory profile exists to distinguish pain in this population, 3) explore the sources of heterogeneity in previous studies examining this question, 4) determine the best therapy for patients with chronic pain, and 5) evaluate the most effective treatment for opioid addiction. We anticipate chronic pain to be an important predictor of continued opioid abuse such that patients with comorbid pain will require careful consideration when managed on OST.
Methods: We systematically reviewed the literature to determine the impact of pain in opioid addiction patients receiving methadone maintenance treatment (MMT). We determined the clinical and inflammatory profile of MMT patients using data from the Genetics of Opioid Addiction (GENOA) research collaborative between the Canadian Addiction Treatment Centres (CATC) and the Population Genomic Program. GENOA is a prospective cohort study aimed to determine the genetic, biological, and psychosocial determinants of treatment prognosis for opioid addiction patients receiving MMT. GENOA recruits patients ≥ 18 years of age meeting the DSM-IV criteria for opioid dependence. All GENOA participants are receiving MMT for the management of opioid addiction. Baseline data from the GENOA pilot study (n=235) were used to evaluate the impact of pain on illict opioid use behaviour and determine the clinical and inflammatory profile of patients with comorbid pain. We explored sources of heterogeneity in previous studies using data from the full-phase GENOA study (n=444), examining the prognostic value of different pain measures for predicting illicit opioid use. We then performed a multiple treatment comparison of all opioid substitution and antagonist therapies in efforts to determine the best intervention for improving treatment outcomes for patients with comorbid pain. We lastly determined the most effective treatment for opioid addiction by performing a network meta-analysis using data from a systematic review of opioid maintenance therapy trials.
Results: Our initial systematic review confirmed a lack of consensus in the literature, whereby some studies suggest pain increases risk for illicit opioid use and other studies suggest pain has no effect on substance use behaviour. Findings from the analysis of GENOA pilot data confirmed chronic pain to be an important predictor of sustained opioid abuse and also showed patients with pain to have elevated Interferon-Gamma. Using data from the GENOA prospective cohort study we determined the Brief Pain Inventory (a commonly used pain measurement in pervious studies) to be highly sensitive with poor prognostic value. Our final reviews propose 1) there is limited evidence to suggest any OST is superior for managing patients with comorbid pain, and 2) heroin and high-dose methadone are the most effective treatments for improving treatment retention. The final systematic review and network meta-analysis in this thesis also highlights a major problem in the treatment of opioid use disorders, primarily the lack of consensus as to what outcomes matter for determining success in patients with addiction.
Conclusion: Patients with comorbid pain and addiction are at high-risk for continued opioid abuse and should be managed closely by clinicians administering OST. Contention in the previous literature likely resulted from the use of pain measurements with poor prognostic value. No OST demonstrated superiority for managing patients with chronic pain. While our findings indicate heroin is the most effective treatment across multiple endpoints, we use this thesis to provide readers with 1) a sense of the feasibility issues associated with heroin administration, 2) a summary of the limitations of this evidence base, and 3) recommendations for how to improve the addiction trials’ design for future research.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: ANALYSIS AND COMPARISON OF USEARCH AND DNACLUST SOFTWARE PACKAGES

contributor:
Smyth, W. F.
Computer Science

subject:
Short reads
Clusters
Similarity

abstract:
Over the past several years, new DNA sequencing technologies have led to a great in-
crease in the quantity of biological sequence data that can be generated. Typically there
may be millions or even billions of short reads sequences of a few hundred base pairs
that are to some degree redundant: the data fall naturally into clusters of sequences
that are highly similar to each other. In order to reduce the time required for analysis
of the data, it therefore becomes of interest to compute representatives of these clusters,
based on some definition of similarity.
In this thesis we examine two clustering software packages, USEARCH and DNACLUST,
that seek to perform this clustering task efficiently. We provide an overview of the techniques used by these two packages; we compare and evaluate them both from a methodological and experimental perspective, and draw conclusions about their effectiveness and utility.

abstract: Thesis

abstract: Master of Science (MSc)


title: A Preparatory Study Towards a Body of Knowledge in the Field of Formal Methods for the Railway Domain

contributor:
Maibaum, Thomas
Gruner, Stefan
Computing and Software

subject:
Formal Methods
Railway Software
Formal Concept Analysis
Body of Knowledge

abstract:
Bodies or Books of Knowledge (BoKs) have only been transcribed in mature fields
where practices and rules have been well established (settled) and are gathered for
any prospective or current practitioner to refer to. As a precursor to creating a BoK,
it is first important to know if the domain contains settled knowledge and how this
knowledge can be isolated? One approach, as described in this work, is to use Formal
Concept Analysis (FCA) to structure the knowledge (or parts of it) and construct
a pruned concept lattice to highlight patterns of use and filter out the common and
established practices that best suit the solving of a problem within the domain.
In the railway domain, formal methods have been applied for a number of years to
solve various modelling and verification problems. Their common use and straightforward
application (with some refinement) makes them easy to identify and therefore a
prime candidate to test for settled knowledge within the railway domain. They also
provide other assurances of settled knowledge along the way.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Energy Management in Grid-connected Microgrids with On-site Storage Devices

contributor:
Sirouspour, Shahin
Electrical and Computer Engineering

subject: Energy Management, Microgrids, Rolling Horizon, MILP, LP, Conditional Value at Risk, Worst-case CVaR

abstract:
A growing need for clean and sustainable energy is causing a significant shift in the electricity generation paradigm. In the electricity system of the future, integration of renewable energy sources with smart grid technologies can lead to potentially huge economical and environmental benefits ranging from lesser dependency on fossil fuels and improved efficiency to greater reliability and eventually reduced cost of electricity. In this context, microgrids serve as one of the main components of smart grids with high penetration of renewable resources and modern control strategies.
This dissertation is concerned with developing optimal control strategies to manage an energy storage unit in a grid-connected microgrid under uncertainty of electricity demand and prices. Two methods are proposed based on the concept of rolling horizon control, where charge/discharge activities of the storage unit are determined by repeatedly solving an optimization problem over a moving control window. The predicted values of the microgrid net electricity demand and electricity prices over the control horizon are assumed uncertain. The first formulation of the control is based on the scenario-based stochastic conditional value at risk (CVaR) optimization, where the cost function includes electricity usage cost, battery operation costs, and grid signal smoothing objectives. Gaussian uncertainty is assumed in both net demand and electricity prices. The second formulation reduces the computations by taking a worst-case CVaR stochastic optimization approach. In this case, the uncertainty in demand is still stochastic but the problem constraints are made robust with respect to price changes in a given range. The optimization problems are initially formulated as mixed integer linear programs (MILP), which are non-convex. Later, reformulations of the optimization problems into convex linear programs are presented, which are easier and faster to solve. Simulation results under different operation scenarios are presented to demonstrate the effectiveness of the proposed methods.
Finally, the energy management problem in network of grid-connected microgrids is investigated and a strategy is devised to allocate the resulting net savings/costs of operation of the microgrids to the individual microgrids. In the proposed approach, the energy management problem is formulated in a deterministic co-operative game theoretic framework for a group of connected microgrids as a single entity and the individual savings are distributed based on the Shapley value theory. Simulation results demonstrate that this co-operation leads to higher economical return for individual microgrids compared to the case where each of them is operating independently. Furthermore, this reduces the dependency of the microgrids on the utility grid by exchanging power locally.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Arcs of Cyclic Order Three in the Conformal Plan

contributor:
Lane, N. D.
Mathematics

subject:
arc
cyclic order
Mobius transformation

abstract: Scope and Contents: This thesis is concerned with the properties of arcs of cyclic order three in the conformal plane. It establishes necessary and sufficient conditions for the union of two arcs of cyclic order three to be again an arc of cyclic order three, and for an arc of cyclic order three to be extensible to a larger arc of cyclic order three.

abstract: Thesis

abstract: Master of Science (MSc)


title: SAFER WALKING ROUTES TO SCHOOL: APPLIED AND METHODOLOGICAL GEOGRAPHIES OF CHILD PEDESTRIAN INJURY

contributor:
Yiannakoulias, Nikolaos
Geography

subject: Child pedestrians; Intersections; Parents Perception; Modelled Probability; Collisions; Motor Vehicles; Safe Route to School; Decision Support Tool; Active Transportation; Safe; Built Environment; School; Case control study

abstract: The study area for this dissertation is Hamilton, Ontario, Canada.

abstract: The general theme of this dissertation is understanding and enabling safe walking routes to school for children.  We restrict our focus to safety issues related to the motorized-transportation environment, thereby defining safety as a function of factors that determine whether or not a child will be struck by a motor-vehicle on their journey to or from school.  Our analysis is unique because it is at a small geographical scale but is representative of an entire urban environment. Working at a small geographic scale allows us to evaluate the variability in safe routes for children within our study area and apply our findings to develop a decision support tool that could be used to plan individualized routes for children in other similar urban environments. Our study area for this dissertation is Hamilton, Ontario, Canada.  The findings in this dissertation contribute ideas about how features of the local road environment may and may not influence risk of collisions between child pedestrians and motor-vehicles.  It also offers methodological insight for future research on pedestrian safety at small geographic scales.  This dissertation demonstrates the potential reduction in the risk of child pedestrian injuries by planning safer routes to school and also introduces methods that can be used to plan safer routes for children. Our results are a reminder of the importance of understanding the interaction between environment and behaviour in research on traffic safety and offer some caution to the notion of a universal 'safe route' to school. Whether or not a particular route to school is safe will very likely be dependent both on the environment and the child's behaviour in that environment.

abstract: Dissertation

abstract: Doctor of Social Science


title: Fracture Toughness of Calcia Partially Stabilised Zirconia

contributor:
Nicholson, P. S.
Metallurgy and Materials Science

subject: crack, grain boundary, cohesion, decohesion, zirconia, weaknening, crack, microcrack, PSZ, partially stabilised zirconia, stress, microstructure, T.E.M., electron, martensitic phase

abstract:
 The room-temperature fracture behaviour of calcia partially stabilized zirconia (PSZ) was investigated. Fracture energy measurements were made using the standard stress intensity calibration and work to fracture techniques. The detailed nature of the PSZ microstructure was studied using scanning electron microscopy, qualitative X-ray analysis and T.E.M, surface replication. The grain structure was detenninod to be bimodal with small grains of pure zirconia dispersed along the boundaries of large grains. These large grains consist of a binary pure-zirconia/stabilized zirconia mixture. An attempt was made to relate the fracture properties to the nature of the inherent flaws present in the material.

 The strength of calcia partially stabilised zirconia was observed to depend on the size and distribution of the grain boundary precipitate of pure zirconia. It is postulated that this grain boundary precipitate causes decohesion and weakening of some of the grain boundaries due to the large internal stresses associated with its martensitic phase transformation. This phenomena of grain boundary decohesion leads to elastic nonlinearity and hysteresis. Crack propagation was always observed to proceed in a slow controlled fashion in this material. A model is proposed to explain theses observations based on the formation of a microcrack zone at the tip of a propagation crack. The occurrence of continued stable crack propagation is believed associated with increasing microcrack zone size with increasing crack length. Evidence supporting this model is presented.

abstract: Thesis

abstract: Master of Science (MSc)


title: Heavy Ion Reactions Proceeding Via 221*Ac Compound Nuclei

contributor:
Macfarlane, R. D.
Physics

subject: high speed recoil transport system, decay, 221*Ac, angular momentum, heavy ion reactions

abstract:
 A high speed recoil transport system is developed making possible the simultaneous study of many decay products of the compound nucleus 221*Ac. Oeterminati ons of the efficiency properties of the transport system, essential for absolute cross section measurements , are discussed in detail.

 A study of angular momentum effects is made possibly by synthesis of 221*Ac using three heavy ion reactions. Absolute cross sections for (HI,xn) and (HI,pxn) reaction products are determined relative to established cross sections for production of 150Dy. Relative cross sections for francium production are also determined.

 A sophisticated statistical model calculation is adapted to provide a framework for interpretation of the results. Some insight is gained into the roles played by basic physical concepts in the systematic of compound nucleus decay in this mass region

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: EVOLUTION OF SINGLE AMINO ACID REPEATS IN EUKARYOTIC SPECIES

contributor:
Golding, Brian
Biology

subject: SAAR Bioinformatics Evolution

abstract: A common feature of eukaryotic genomes is the abundance of simple sequences. Single amino acid repeats, which is one kind of simple sequences, are characterized by tandem recurrence of only one amino acid within the proteins and are broadly found among almost all genomes of eukaryotic species. Combined with its abundance, the lack of deterministic function of SAAR makes it intriguing to study on its evolution. In this study, 34 eukaryotic genomes are used and an abundance of SAARs on X/Z chromosomes is observed. Also, amino acid composition and codon usage bias is different between SAARs and non-repetitive regions. We also observe that the conserved number of SAARs is linearly correlated with logarithm of divergence time.

abstract: Thesis

abstract: Master of Science (MSc)


title: THE EFFECT OF MULTIMEDIA DESIGN ON LEARNING AND PERCEPTION ACROSS THE LIFESPAN

contributor:
Kim, Joseph
Milliken, Bruce
Psychology

subject: PhD Dissertation

abstract: The goal of this dissertation was to examine the effect of multimedia design strategies on learning across the lifespan and across working memory capacities.  The introduction outlines the main theoretical frameworks that constitute multimedia research, and the preliminary research that facilitated the articles represented in this sandwich thesis.  The key contributions were 1) the replication of the negative effect of redundant text compared to complementary images on multimedia learning in younger adults, and an interesting reversal effect in older adults who benefited from redundant text and were impaired by images, 2) the finding that learners were unable to recognize ineffective presentations even when given direct exposure to both effective and ineffective designs, and 3) the demonstration that working memory capacity (WMC) predicted learning from various presentation designs—with poorly designed presentations selectively hindering low WMC learners, while pedagogically-sound presentation designs mediated differences in WMC and homologized performance.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)