title: A Unified Theory of Model Reduction for Linear Time Invariant Dynamical Systems

contributor:
Sinha, Naresh K.
Electrical Engineering

subject:
Electrical and Electronics
Electrical and Electronics

abstract: The approximation of linear, time-invariant, dynamical systems by similar systems having fewer state variables is investigated. A class of reduced-order approximants called nonminimal partial realizations is introduced which includes many published methods as special cases, and thus represents a unification of the theory of model reduction. Since the concept of linear state variable feedback is central to many of the design procedures of modern control theory, the behaviour of the approximated system to such feedback laws derived from analysis of the approximating system is studied. The specific results derived give a credibility heretofore nonexistant to the class of reduced models called minimal partial realizations by virtue of the fact that they form a subclass of the nonminimal partial realizations. The use of canonical form state equations is advocated as a means of simplifying the computational procedure for an important class of reduced models termed aggregated partial realizations. Such realizations are shown to be useful for designing suboptimal linear quadratic servomechanism compensators, since guaranteed stability of the large-scale system is possible.

abstract: Doctor of Philosophy (PhD)


title: Older adults' perceptions of financial technologies

contributor:
Gillett, James
Campbell, Lori
Ryan, Ellen
Health and Aging

subject:
financial technologies
life course perspective
older adults
Social and Behavioral Sciences
Social and Behavioral Sciences

abstract:
Western democratic societies are currently experiencing an interesting convergence of trends: population aging and rapidly advancing technology. In our increasingly digital economy, it is important to be reflective on the effects of technological evolution in our institutions. Older adults have observed many changes as we have entered the information age. Their experience with this evolution has been documented in the literature in understanding the acceptance and use of information and communication technologies (ICT), most frequently the personal computer. This thesis contributes to and extends the existing interdisciplinary scholarship on older adults and technology, broadening the scope from that of the individual to the societal level. I examine how institutional changes in the public sphere, specifically technological advances in the financial system accompanying the digital economy, are perceived by older adults.

A mixed methods study was conducted composed of a forty item mailed out questionnaire and twelve in person interviews recruited through the McMaster SHARE group. The analysis of this work was conducted with an interpretivist ontology, understanding the co-creation of technology and society. Theoretically, the life course perspective was important in framing this work. Analysis revealed three major themes that have been described in the thesis in individual chapters: ideas of subjective age, risk and trust, and gender and intersectionality.

Consistently in this project, discussions of financial technologies blended with older adults’ perceptions of technology in a broader sense. This both evidenced the life course perspective and comments on the pervasive influence of technology in our society.

abstract: Master of Arts (MA)


title: MOLECULAR RESPONSES OF LUNG CANCER TO IONIZING RADIATION: INVESTIGATION OF THE BIGUANIDE METFORMIN IN COMBINATION WITH IONIZING RADIATION

contributor:
Tsakiridis, Theodoros
Singh, Gurmit
Hirte, Hal
Medical Sciences

subject:
AMPK
cancer
ionizing radiation
radiosensitizer
metformin
lung cancer
Medical Molecular Biology
Medical Molecular Biology

abstract:
Purpose

To examine the potential of the anti-diabetic agent Metformin (MET) to enhance responses of NSCLC to ionizing radiation (IR).

Experimental Design

Human NSCLC A549, H1299 and SK-MES cells were treated with IR, MET or the mTOR inhibitor rapamycin and subjected to proliferation, clonogenic, immunoblotting, cell cycle and apoptosis assays. A549 and H1299 cells were grafted into flanks of immunosuppressed mice and treated with MET and/or IR. Tumours were analyzed by immunoblotting and immunohistochemistry.

Results

MET(2.5uM-5mM) caused dose-dependent inhibition of proliferation (10-70%)in all lines, inibited clonogenic survival and sensitized cells to IR. In A549 cellsMET caused inhibition of proliferation comparable to rapamycin, stimulated expression and activation of the ATM and AMPK-p53-p21cip1and inhibited the Akt-mTOR-4-EBP1 pathway.MET caused G1 arrest of cell cycle, enhanced apoptosis and induced sustained DNA repair foci of gH2AX. MET and IR alone inhibited xenograft growth and combined treatment enhanced that further. IR and MET induced sustained enhancement of expression and activity of ATM-AMPK-p53-p21cip1and inhibitionof Akt-mTOR-4-EBP1 pathways in tumours also. MET reduced expression of angiogenesis and enhanced expression of apoptosis markers in both control and radiated tumours.

Conclusions

Clinically achievable(uM) doses ofMET inhibit human NSCLC cell and tumour growth and sensitize them to IR.This is accompanied by desirable modulation of molecular signals, inhibition of angiogenesis and induction of apoptosis. Our results suggest that MET could be a clinically useful adjunct to radiotherapy in NSCLC and support clinical investigation of MET in combination with radiotherapy.

abstract: Master of Science (MSc)


title: Transition to Parenthood for First-Time Fathers Whose Partners have Postpartum Depression

contributor:
Sword, Wendy
Jack, Susan
Wahoush, Olive
Nursing

subject:
postpartum depression
transition to parenthood
fathers
partners
support
public health
Public Health and Community Nursing
Public Health and Community Nursing

abstract: Postpartum depression (PPD) is a mental health condition present in 13% of new mothers. It is a serious public health issue that profoundly impacts the health of mothers, their children, and their partners. While the short- and long-term implications of maternal mental health for children’s growth and development have been well documented, little has been written about the impact of maternal PPD on partners. In particular, the effects of PPD on new fathers have received little attention. This qualitative descriptive study examined, through the sharing of photographs by participants and in-depth interviews (n = 10), the experience of the transition to parenthood for first-time fathers whose partners have PPD. It also compared their expectations of fatherhood with the lived reality of the experience and explored fathers’ perceptions of, and access to, health services and supports. The main themes that emerged from the data analysis were: From two to three, Connecting with baby, PPD and the partner relationship, Heightened involvement with baby, and Available and desired supports. Sub-themes that captured more specific patterns in the data also were identified. The study findings have implications for establishing best practices that are inclusive of support and education for partners.

abstract: Master of Science (MSc)


title: Counting Canucks: cultural labour and Canadian cultural policy

contributor:
Yates, Charlotte A.B.
Graefe, Peter
Zemans, Joyce
Political Science

subject:
cultural policy
cultural labour
comparative public policy
creative economy
political economy
Comparative Politics
Comparative Politics

abstract:
My research examines the political role of unions, as the collective voice of Canadian cultural workers, in connection to the cultural policies that shape their memberships’ personal and professional lives. I examine the policy advocacy strategies of Alliance of Canadian Cinema, Television and Radio Artists; the Directors Guild of Canada; the Writers Guild of Canada; the Communication, Energy and Paperworkers Union of Canada; and the International Alliance of Theatrical and Stage Employees IATSE, as members of federal and provincial cultural policy networks.

I argue that changes in cultural policy influence the level of participation and the political strategies of the unions and guilds in federal and provincial cultural policy networks. Shifts in organizational and political strategies affect the ways that unions articulate their interests as policy problems; this, in turn, affects the ways in which issues and problems are understood and acted upon by decision-makers in policy reforms. While most of the unions and guilds, particularly at the federal level, have been active in cultural policy networks for several decades, unions at both federal and provincial levels are increasingly partnering with the employers – the independent producers – in their policy interventions. Analysis of my case studies leads me to conclude that this strategy is paradoxical for unions. While a partnership approach from a “production industry” standpoint arguably increases union access to and credibility with policy decision-makers, it can compromise or obscure how unions articulate cultural policy problems as labour problems. When unions engage in policy advocacy either independently or as a labour coalition, the direct relationship between cultural policy and its specific impact on labour markets and working conditions is most evident.

abstract: Doctor of Philosophy (PhD)


title: Kinetics and Thermodynamics of (1+2) Cycloadditions of Transient Diphenylgermylene with Alkenes

contributor:
Leigh, William J.
Baca, Ignacio Vargas
M., Paul H.
Chemistry and Chemical Biology

subject:
germylene
germirane
photochemistry
transient
thermodynamics
kinetics
(1+2) cycloaddition
stability
Inorganic Chemistry
Organic Chemistry
Physical Chemistry
Inorganic Chemistry

abstract:
1,1-Dimethyl-3-phenyl-1-germacyclopent-3-ene (32) was synthesized and it was used for the study of the reactivity of diphenylgermylene (GePh2) toward alkenes using steady state and nanosecond laser flash photolysis technique (nLFP) in hexanes solution.

The reactivity of GePh2 toward several alkenes including 1-hexene, cis-2-hexene, trans- 3-hexene, cyclopentene, cyclohexene, cis-cyclooctene, methylcyclohexene, 2-methyl-2- pentene, 2-methyl-1-pentene and trans-3-methyl-2-pentene has been investigated by nLFP method. In all cases, the equilibrium constant was measured and it was found that there is a direct correlation between the Gibbs free energy of the reaction (∆Gr) and the ionization potential (IP) of the involved alkene. This indicates that alkenes with higher IP, electron poor alkenes, should lead to more stable germiranes and consequently installation of electron withdrawing groups on alkenes should stabilize the resulting germirane. This is the first time such a quantitative predictor is reported.

Steady state photolysis methods have been used to investigate same aspects of germirane reactivity. Photolysis of 32 in the presence of acrylonitrile and methanol in one experiment, and 3,3-dimethyl-1-pentene and methanol in another experiment, has provided more evidence for the presence of the corresponding germiranes which were trapped by methanol.

Finally, the (1+2) cycloaddition reactions of GeH2, GeMe2 and GePh2 with a selection of alkenes were investigated computationally using different DFT methods and 6-311+G(d,p) as the basis set. The results show that the reaction becomes less exergonic moving from GeH2 to GeMe2 and then to GePh2. In addition, plots of calculated ∆Gr against the experimental IP of the involved alkene reproduced the observed experimental correlation from the laser studies. It was also concluded that ωB97XD and mPW1PW91 are the most reliable of the DFT methods that were investigated.

abstract: Master of Science (MSc)


title: UNDERSTANDING THE LINK BETWEEN RELIGIOUS SERVICE ATTENDANCE, CORONARY HEART DISEASE AND RELATED RISK FACTORS IN CANADA: A MIXED METHODS STUDY AND FUTURE DIRECTIONS FOR HEALTH PROMOTION.

contributor:
Oremus, Mark
Boyle, Michael H.
Strachan, Patricia
Health Research Methodology

subject:
Religious Service Attendance
Coronary Heart Disease
Diabetes
High Blood Pressure
Mix Methods
Health Promotion
Cardiovascular Diseases
Clinical Epidemiology
Community Health
Other Mental and Social Health
Public Health Education and Promotion
Cardiovascular Diseases

abstract:
Research examining the relationships between religious indicators and the cardiovascular health of individuals and populations has been relatively understudied in the Canadian context. This thesis contains three main studies, developed from a sequential explanatory mixed method research design.

The first study examined the association between the frequency of religious service attendance (RSA) and prevalence of coronary heart disease (CHD), diabetes and high blood pressure in Canada. The Saskatchewan sample of the Canadian Community Health Survey (CCHS-4.1) was used to build multivariable logistic regression models. The analysis revealed participants who attended religious services more than once a week had lower prevalent odds of CHD (OR= 0.82, 95% CI 0.61-1.11, p>0.05), diabetes (OR=0.60, 95% CI 0.45-0.80, p

The second study was qualitative and undertaken to help interpret and explain the quantitative results from the CCHS. Twelve semi-structured interviews with ordained pastors and three focus groups with parishioners in Catholic, Anglican and United churches were conducted in Canada. The findings suggest that attending religious services: (1) promotes mental health; (2) provides social support and activities; and (3) promotes health and lifestyle behaviours to lower CHD risk.

Qualitative data from the second study was used for the third study, which identified relevant factors associated with the implementation of heart health promotion programs in churches. Among the various factors identified, pastor leadership, funding for a parish nurse, community-focused interventions, secured infrastructure and social support were important to facilitate health promotion programs in churches.

abstract: Doctor of Philosophy (PhD)


title: A Mouse Model of Deep Vein Thrombosis Stability: The Effect of Direct Thrombin Inhibition

contributor:
Gross, Peter L.
Health Sciences

subject:
Deep vein thrombosis
pulmonary embolism
thrombus stability
anticoagulants
intravital microscopy
Hematology
Hematology

abstract: The effect of direction thrombin inhibition on acute deep vein thrombosis (DVT) stability has not been defined and could contribute to pulmonary embolism (PE) risk. Direct thrombin inhibitors (DTIs) effectively inhibit free and clot-bound thrombin, which could potentiate thrombus instability through disruption of platelet, fibrin, and FXIIIa stabilizing mechanisms. This could manifest as increased thrombus embolization. A clinically relevant mouse model of DVT stability could further our understanding of venous thrombosis pathophysiology and define the effect of direct thrombin inhibition on PE. We hypothesized that acute DTI administration would decrease acute DVT stability and potentially increase PE risk. Platelets were labeled in vivo, femoral vein thrombosis was induced using FeCl3, and lepirudin (8U/g) was administered after clot formation. Using intravital videomicroscopy (IVM), real time embolization was quantified as a measurement of thrombus stability. Thrombus stability increased in the control group and decreased in the lepirudin-treated group over two hours. The decrease in α2-antiplasmin (α2-AP) content within lepirudin-treated thrombi, compared to control thrombi, could possibly contribute to the observed decrease in thrombus stability. Continued growth and embolization established the dynamic nature of formed thrombi. In both groups, emboli were detected in the pulmonary artery circulation. Therefore, we successfully developed a mouse model of venous thrombus stability, which imitated the clinical progression of DVT to PE. DTI administration in the acute DVT setting could decrease thrombus stability, demonstrated through increased embolization and PE. This model could be useful in examining the effect of other antithrombotics and risk factors settings on DVT stability.

abstract: Master of Science (MSc)


title: Magnetic Resonance and Radiography in Rheumatoid Arthritis: Intermodality Comparisons of Erosion Detection

contributor: Colin E. Webber; Karen A. Beattie; Maggie Larche

contributor: Medical Sciences (Division of Physiology/Pharmacology)

subject: Arthritis

subject: Rheumatoid; Magnetic Resonance Imaging; Radiography

subject: Clinical Epidemiology

subject: Other Analytical, Diagnostic and Therapeutic Techniques and Equipment

subject: Rheumatology

subject: Clinical Epidemiology

abstract:
BACKGROUND. Classically, radiography (x-ray) has been used to visualize the destructive effects of uncontrolled rheumatoid arthritis (RA) on articular bones. Both x-ray and magnetic resonance imaging (MRI) may be used to visualize erosive disease. The multi-slice and multi-planar characteristics of MRI provide greater detail per anatomy imaged than x-ray.

OBJECTIVE. The objective of this dissertation was to compare the relative merits of x-ray and MRI erosion detection.

METHODS. In Chapters 1 through 3, RA, its clinical management, and the role of diagnostic imaging were introduced. In Chapter 4, the overall objective was first investigated by evaluating the current state of knowledge using a systematic review. In Chapter 5, inter-rater reliability across four participating radiologists was investigated. In Chapter 6, reliability-adjusted evaluations were used to directly compare paired x-ray and MR images.

RESULTS. The systematic review indicated that x-ray has low sensitivity and high specificity for MRI erosions. The associations were dependent on RA symptom duration. The findings from the prospective studies conducted were consistent with the literature. In a patient-centred analysis, the proportion of patients with erosive disease detected on either modality was dependent on the anatomy compared. Despite similar proportions of patients with erosive disease detected in comparable diagnostic imaging sittings, the proportions were comprised of markedly different patients.

CONCLUSIONS. The literature comparing x-ray and MRI erosion detection was systematically reviewed. The dependence of the relative diagnostic test accuracy on symptom duration was highlighted. At the patient level of analysis, the greater number of anatomical sites examined on x-ray overcomes the superiority of MRI to detect erosions at the unit of measurement. The two modalities are complementary insofar that they detect erosive disease in distinct patients. Further investigation into the merit of imaging varied anatomy on MR and optimally accounting for inter-rater reliability in such comparisons is warranted.

abstract: Doctor of Philosophy (PhD)


title: A Controllability Study of TRUMOX Fuel for Load Following Operation in a CANDU-900 Reactor

contributor:
Luxat, J. C.
Engineering Physics

subject:
CANDU
Load following
TRUMOX
Controllability
Nuclear Engineering
Nuclear Engineering

abstract:
The CANDU-900 reactor design is an improvement on the current CANDU-6 reactor in the areas of economics, safety of operation and fuel cycle flexibility. As power grids start to rely more heavily on nuclear, it will be imperative for future nuclear generating station designs to be able to adjust their output to suit the fluctuating demands of the grid. Additionally, the need to reduce global nuclear waste has motivated research into mixed oxide fuel with the goal of maximizing spent fuel repository capacity and reducing decay heat via transmutation of transuranic actinides. The objective of this thesis is to provide insight into the load following capabilities of the CANDU-900 reactor design for a transuranic mixed oxide (TRUMOX) fueled core.

The three-dimensional fuel management code, RFSP-IST, was used to simulate a reactor operating history for week long load following operations in a generic CANDU-900 reactor. Daily refuelling operations as well as reactivity device movements supplementary to RFSP were performed using the RECORD RRS emulator program. Core snapshots were taken at periodic intervals using the SIMULATE module to observe and track various reactor parameters. Average liquid zone controller fills as well as core reactivity and channel power values were used to determine the controllability of the reactor for various load following depths.

The results of the load following simulations show that TRUMOX fuel has superior load following capabilities to that of conventional NU fuel for practical operational scenarios in a CANDU-900 reactor. Load following operations could be performed for TRUMOX fuel down to 85% full power in a safe and controllable manner using only the liquid zone controllers to account for the xenon transient reactivity as compared to NU which could only be done down to 90% full power. For load following simulations that both fuel types were capable of performing in a controllable manner, the TRUMOX fuelled core maintained on average a larger safety margin between the average liquid zone controller fills and the established safety limits.

abstract: Master of Applied Science (MASc)


title: Cortical Plasticity and Tinnitus

contributor:
Becker, Suzanna
Bruce, Ian C.
Reilly, James
Neuroscience

subject:
auditory
cortical plasticity
tinnitus
homeostatic plasticity
hearing loss
Computational Neuroscience
Systems Neuroscience
Computational Neuroscience

abstract:
Tinnitus is an auditory disorder characterized by the perception of a ringing, hissing or buzzing sound with no external stimulus. Because the most common cause of chronic tinnitus is hearing loss, this neurological disorder is becoming increasingly prevalent in our noise-exposed and ageing society. With no cure and a lack of effective treatments, there is a need for a comprehensive understanding of the neural underpinnings of tinnitus. This dissertation outlines the development and validation of a comprehensive theoretical model of cortical correlates of tinnitus that is used to shed light on the development of tinnitus and to propose improvements to tinnitus treatment strategies.

The first study involved the development of a computational model that predicts how homeostatic plasticity acting in the auditory cortex responds to hearing loss. A subsequent empirical study validated a more biologically plausible version of this computational model. The goal of these studies was to determine whether and how a form of plasticity that maintains balance in neural circuits can lead to aberrant activity in the auditory cortex. The final study extends the validated computational model to develop a comprehensive theoretical framework characterizing the potential role of homeostatic and Hebbian plasticity in the development of most major cortical correlates of tinnitus.

These theoretical and empirical studies provide a novel and complete description of how neural plasticity in adult auditory cortex can respond to hearing loss and result in the development of tinnitus correlates.

abstract: Doctor of Philosophy (PhD)


title: Quantitative Electromyographic and Goniometric Analyses of Normal and Pathological Human Gaits

contributor:
Milner, M.
Electrical Engineering

abstract:
This thesis is directed generally towards a deeper understanding of normal and pathological biped locomotion. Attention has been focussed mainly on electromyographic (EMG) and kinematic aspects of gait. Emphasizing consistency and repeatability of acquired data, the characteristics of surface EMG signals from m. vastus lateralis and m. rectus femoris during several steps of level walking under controlled repeatable gait conditions at three different speeds for several normal subjects have been studied. The variance ratio, a statistical descriptor for repeatability, has been devised. The findings indicate that the variance ratio offers a simple means for selecting an optimal processor for rectifying and averaging the signals. It is of value also in determining an optimal location for surface electrodes on a muscle.

Included in the thesis is original research relating to kinematic information presented in the form of knee-angle/hip-angle diagrams. Cyclic loops which had been utilized in the past mainly for their visual representation have been quantified using a shape recognition technique. Quantitative analyses of angle-angle diagrams associated with 5 normal subjects, an above-knee (A/K) amputee and a cerebral-palsied (C.P.) patient, who had an implanted cerebellar stimulator, were carried out. The quantification and physical interpretations of the parameters extracted from the angle-angle diagrams provided a valuable adjunct to visual assessment of the gaits and elicited significant information regarding overall coordination and control during each gait. Using these methods an in-depth assessment of the efficacy of the cerebellar stimulator implanted in the C.P. patient was accomplished.

The thesis also describes an initial attempt, using the methods of time series analysis, at modelling the transfer function between several inputs given by the EMG signals of selected muscle groups and an output which is either the hip or knee angle trajectory. The model was able to suggest which individual muscles were synergistic, whether the inputs chosen were good predictors of the output and the relative contribution of each input in predicting the output.

abstract: Doctor of Philosophy (PhD)


title: The Origin of Sin in Irenaeus and Jewish Apocalyptic Literature

contributor:
Sanders, E. P.
Religion

subject: Religion Religion

abstract:
The thesis contends that Irenaeus depended directly and indirectly on an earlier Jewish tradition both for his interpretation of New Testament texts and for the final formulation of his own ideas on sin and its origin.

This earlier Jewish tradition is substantially available to us in the "Apocrypha and Pseudepigrapha of the Old Testament".Irenae1"s drew on these writings as a hermeneutical key to the sense of Biblical texts. For him the Old Testament Apocrypha belonged La the Biblical canon, but the thesis mainly focuses on pseudepigraphal material when even from Irenaeus' standpoint was non-Biblical.The motifs from this literature which shaped his thinking about sin and its origin were apoca1yptic.

The lines of argument establishing the thesis are various.The two principal lines turn, respectively,on (a) Irenaeus' explicit use of motifs peculiar to pseudipgraphal texts, and (b) the implicit use of such motifs in interpreting canonical Biblical passages. Thus the thesis is essentially a study in the history of ideas. There is, however, a third, supportive line of argument which belongs to literary criticism as such: There are a few instances in which it appears likely that there is a direct literary relationship between Irenaeus and one of the pseudepigrapha. The proof must remain tentative, since in even the best cases only Latin translations of Irenaeus and the pseudepigraphal writing are available, although Irenaeus wrote in Greek and probably read the pseudepigrapha in a Greek version. In these instances, however, it is possible at least to compare Latin translation with Latin translation in noting the verbal and other similarities. In other instances, in which the pseudepigraphal text being compared is extant only Syriac, Ethiopic, or Slavonic, or in which Irenaeus' writing is extant only in Armenian, the English translations are used. In general, standard English translations of both Irenaeus and his pseudepigraphal sources are used in the thesis, in accord with the nature of its principal purposes and arguments.)

The thesis does not aim at providing a new view of the meaning of sin in the theology of Irenaeus, although the role of sin in Irenaeus Y thought is necessarily analyzed in the course of the thesis. The most recent scholarly treatments of Irenaeus' doctrine of recapitulation and of the place and significance of Satan, Adam, and sin in that doctrine are seen to be accurate and satisfactory, although correction may be possible on one or two individual points. The intention of the thesis. however, is only to identify the sources of Irenaeus' various statements about the origin of sin rather than to offer a new interpretation of Irenaeus' theology.

Though the thesis explicitly concludes only to Irenaeus' dependence on the pseudepigrapha for his thinking about sin and its origin, it raises the question of how dependent on such sources was the entire body of patristic thought which culminated in Augustine's formulation of "original sin".

abstract: Doctor of Philosophy (Medical Science)


title: Photographic Fluid Velocity Measurement in a Hydrocyclone

contributor:
Woods, D.R.
Engineering

subject: Engineering Engineering

abstract: The three dimensional flow patterns in a 3 inch diameter hydrocyclone operating without an air core were studied usina tracer particles and high speed cine photography. The cyclone was constructed and operated according to present design criteria for the optimum separation of Liquid-solid mixtures. Both cyclone geometry and operating conditions were the same throughout al I experiments analysis of fi Ims posed at 55 locations inside the hydrocyclone provided data for 18 velocity profi les which described the three dimensional flow in the hydrocyclone. This data was then checked for consistency by material balance considerations and compared with the results of earlier investigators who operated their cyclones with air cores.

abstract: Master of Engineering (MEngr)


title: BLOOD PRESSURE CHANGES BY AGE FROM CHILDHOOD TO ADOLESCENCE IN SOUTH ASIAN CHILDREN

contributor:
Yusuf, Salim
Teo, Koon K
Mente, Andrew
Health Research Methodology

subject:
blood pressure
children
adolescents
overweight
obesity
south asia
Pediatrics
Pediatrics

abstract:
Research statement:

To investigate the age specific blood pressure change in South Asian children from childhood to adolescence over a six year period and to determine whether this change of blood pressure varies by baseline characteristics.

Rationale:

Children exhibit age related incremental changes in blood pressure from birth onwards which reach adult levels during late adolescence. The best way to measure age-related changes in blood pressure from childhood to adolescence is through prospective longitudinal studies.

Objectives:

to investigate the changes in blood pressure among South Asian children aged 6 to 11 years who were followed for a period of six years.

Methods:

Blood pressure and anthropometric data were collected from 703 children who were 5 to 11 years of age in 2005 and were re-examined after six years (age range of 11 to 17 years in 2011). Average difference between baseline and follow-up blood pressure measurements was evaluated using the paired t-test. A linear regression model with follow up blood pressure and blood pressure change as outcomes and sex, weight, and height as regressors were fitted to assess whether these predictor variables were associated with the dependent variables.

Summary of results:

Systolic and diastolic blood pressure increases from childhood to adolescence. Baseline blood pressure appears to be the strongest predictor of follow up blood pressure. Change in body mass index influences blood pressure more than baseline body mass index. Boys showed higher levels of change in systolic blood pressure compared to girls. Age showed an interaction with sex for change in systolic blood pressure. Boys exhibited higher change in systolic blood pressure than girls in older age groups compared to younger age groups.

Potential implications:

The study findings will increase awareness about high blood pressure in children and lead to preventive strategies to contain the burden of hypertension in future.

abstract: Master of Science (MSc)


title: Different Approaches to Improve Metamorphic Buffer Layers Grown on a GaAs Substrate

contributor:
Cassidy, D.T.
Thompson, David A.
Engineering Physics

subject: Metamorphic Buffer Layers

subject: Pseudo-substrate

subject: GaAs

subject: Cross-hatch

subject: Low temperature layer

subject: InGaAs

subject: InGaAsP

subject: Electronic Devices and Semiconductor Manufacturing

subject: Semiconductor and Optical Materials

abstract: Metamorphic buffer (MB) layers were studied as a means to grow epilayers on top of a GaAs substrate which have different lattice constant than the GaAs. Growths were done by molecular beam epitaxy on a GaAs (001) substrate. The growths of step-graded InGaAs and InGaAsP MBs have been investigated using both linear and logarithmic grading profiles. The logarithmic grading profile shows slight improvement in the crystal quality over the linear grading profiles. This is an indication that instead of increasing the strain with the same grading rate, it may be helpful to have higher grading rate at the beginning and lower grading rate at the end of the buffer. InGaAsP graded buffers were grown where group III ratio was kept fixed. However due to the existence of phase separation and lower relaxation the quaternary growths exhibited no performance improvement as might have been expected from growths with only group V grading. Also, the effects of using an InGaP layer grown at low temperature before the MB were determined. Quantum wells (QW), which were grown on top of the MBs, were used to probe the optical emission properties. No significant difference was observed in photoluminescence between the samples with a low temperature layer and without a low temperature layer. Annealing enhanced the PL intensity but the crystal quality degraded due to the appearance of surface defects. Surface undulations, known as “cross-hatch” (CH), were observed in the top MB layers. Atomic force microscopy (AFM) was used to analyze the surface morphology and degree of polarization (DOP) measurement was used to analyze the strain features in the final MB layer. Similar patterns of both surface morphology and strain field indicate a correlation between these two. From analysis of the periodicity of strain field and the CH, evidence was found in the support of one of the existing models of CH evolution which implies that the CH appears before the formation of MDs and subsequently MDs form at some troughs in the undulation.

abstract: Master of Applied Science (MASc)


title: ALTERING A LEGACY: REWRITING DEFOE IN J.M. COETZEE’S FOE

contributor:
Zuroski-Jenkins, Eugenia
Walmsley, Peter
Monture, Rick
English and Cultural Studies

subject:
Daniel Defoe
J. M. Coetzee
Foe
Friday
Robinson Crusoe
Susan Barton
Other English Language and Literature
Other English Language and Literature

abstract: Much of the critical discourse on J.M. Coetzee’s Foe does not fully investigate its relationship with Daniel Defoe’s texts, despite Foe’s intimate relation with them. This thesis offers a postcolonial reading of Coetzee’s Susan Barton, Cruso and Friday against Daniel Defoe’s original characters Roxana, Robinson Crusoe and Friday. Chapter one discusses Roxana-as-feminist, female colonizer, representative of her sex and Amazon and compares her to Barton. It reveals the tendency of critical discourse to attempt to ‘know’ Barton as they ‘know’ Roxana, by categorizing her, and reveals how Coetzee’s character frustrates attempts to define her. The second chapter addresses eighteenth-century knowledge of race and how it differs from present day, which offers an alternate reading of Robinson Crusoe and complicates its use as a colonial handbook. I also discuss masculinity in Defoe’s Robinson Crusoe as an individual characteristic Coetzee alters into something that can be appropriated. His characters are not masculine but can wield phallic symbols such as the pen and the knife to reveal power as systemic rather than individualistic. The final chapter offers an in depth postcolonial reading of Friday and interrogates critical discourse’s tendency to read him as representative of ‘the colonized,’ or as a colonial trope.

abstract: Master of Arts (MA)


title: THE ASSOCIATION BETWEEN FAMILY FUNCTION AND CHILD BEHAVIOUR AND ITS RELATIONSHIP WITH EXPENDITURES FOR USE OF HEALTH AND SOCIAL SERVICES AMONG CHILDREN/YOUTH WHO SURVIVE TRAUMA

contributor:
Browne, Gina B.
O`Mara, Linda
Thabane, Lehana
Nursing

subject:
Trauma
children
family function
child behaviour
Family Practice Nursing
Other Nursing
Pediatric Nursing
Family Practice Nursing

abstract: To date most research on long-term outcomes of childhood trauma has focused on traumatic brain injuries, but less is known about traumatic injuries not involving the brain. Since traumatic brain injuries can have persistent effects on child behaviour, I investigated whether other types of traumatic injuries could also affect child behaviour in the long term. Currently, limited information is available on possible associations between family function and child behaviour after child trauma; knowledge of the long-term costs of pediatric trauma is also lacking. The main goal of this study was to determine whether family function was associated with behaviour in children who experienced a traumatic injury eight to ten years ago. Additional goals were to determine current expenditures and use of health and social services by child trauma victims and their parents. Pediatric trauma victims were selected from a trauma database at a tertiary care hospital in the Hamilton-Wentworth region. The parents of these children were interviewed to obtain children’s current behaviours and the family’s use of health and social services. The results showed that injury severity was not associated with child behaviour, but associated with family functioning. No relationship was found between health and social service expenditures for children and their injury severity, but there was a relationship between parent health and social service expenditures and child injury severity. The results do not support an association between child behaviour and injury severity following trauma, but they do suggest that expenditures and use of services by injured children and their families are affected long-term. The results suggest that future health and social service uses of injured children and their families may be better understood and planned for by recognizing the continuing effects of trauma. This information could help making appropriate health and social service programs more available to this population.

abstract: Master of Science (MSc)


title: NMR STUDY OF THE POTASSIUM IRON SELENIDE HIGH-TEMPERATURE SUPERCONDUCTOR

contributor:
Imai, Takashi
Physics and Astronomy

subject: Superconductvitiy

subject: nuclear magnetic resonance

subject: potassium iron selenide

subject: high-temperature iron-based superconductor

subject: Condensed Matter Physics

subject: Condensed Matter Physics

abstract: In this thesis we present a 77Se NMR study of the iron selenide based high-temperature superconductor KxFe2−ySe2 (Tc = 33 K). We observe NMR lineshapes as narrow as ∼ 4.5 kHz with an applied field along the crystal c-axis, and find no evidence for the co-existence of magnetic order with superconductivity. With an applied field along the ab plane, however, the lineshape splits into two peaks of equal intensities at all temperatures, suggesting that the tetragonal fourfold symmetry of the average structure may be locally lowered by vacancy superstructure. Knight shift data indicate that spin susceptibility decreases progressively with temperature, similar to other iron arsenide high-Tc systems. In the nuclear spin-lattice relaxation rate 1/T1 we observe no Hebel-Slichter coherence peak, nor any enhancement in low frequency antiferromagnetic spin fluctuations in 1/T1T. We also report on the effects of sulphur (S) substitution on the selenium sites in this system by conducting 77Se NMR measurements on KxFe2−ySe2−zSz (z = 0.8, 1.6). We find that both spin susceptibility and low frequency spin fluctuations are suppressed with increasing S content along with Tc.

abstract: Master of Science (MSc)


title: ADVANCED STRUCTURAL AND FUNCTIONAL MAGNETIC RESONANCE IMAGING IN CHRONIC LOW BACK PA

contributor:
Noseworthy, Michael
Kumbhare, Dinesh
Harish, Srinivasan
Biomedical Engineering

subject: Low Back Pain

subject: Magnetic Resonance Imaging

subject: Diffusion Tensor Imaging

subject: Blood Oxygen level Dependent MRI

subject: Erector Spinae

subject: Multifidus

subject: Bioimaging and biomedical optics

subject: Musculoskeletal System

subject: Other Biomedical Engineering and Bioengineering

subject: Other Kinesiology

subject: Other Life Sciences

subject: Bioimaging and biomedical optics

abstract:
An objective measure of muscular low back pain (LBP) symptoms eludes clinicians. This study assessed efficacy of magnetic resonance imaging (MRI) of the lumbar multifidus using diffusion tensor imaging (DTI), blood oxygen level dependent (BOLD) signal fractal dimension (FD) analysis and muscle cross sectional area (CSA) in LBP assessment. MRI results were compared to two questionnaires, the Oswestry disability index (ODI) and visual analog score (VAS).

Right-left asymmetry in both DTI metrics and T2-weighted (T2W) CSA were greater in the injured. Also, asymmetry measures were correlated with body mass index (BMI) but not age, height, or level of physical activity (measured via Godin activity questionnaire). The relationship between asymmetry and LBP symptoms in T2W and DTI scans increased for subjects with BMI below 35kg/m2.

BOLD FD did not scale with LBP symptoms. However, FD analysis showed promise following therapeutic Swedish massage, hypothesized as being related to local perfusion changes, indicating that FD is sensitive to changes in the lumbar muscle, just not LBP symptoms. Thus the BOLD FD does change with treatment, just not with the symptoms of LBP.

When combining data from multiple scan types, the symptoms of LBP correlated best with the unweighted mean of DTI fractional anisotropy (FA) and T2W CSA asymmetry, and the correlation was greatest (R2=0.88) when only symptomatic (not both symptomatic and control) subjects with BMIs from 18-25kg/m2 were considered. From these results there appears to be clinical utility in characterizing the symptoms of non-acute LBP using DTI and CSA.

abstract: Doctor of Philosophy (PhD)


title: Linear Mixed Effects Model for a Longitudinal Genome Wide Association Study of Lipid Measures in Type 1 Diabetes

contributor:
Canty, Angelo
Mathematics and Statistics

subject:
Linear Mixed Effects Model
Genome Wide Association Study
Longitudinal Data
Lipid Measures
Type 1 Diabetes
Covariance Structure
Biostatistics
Biostatistics

abstract:
Hypercholesterolemia is the presence of high levels of cholesterol in the blood, and it is one of the major factors for the development of long-term complications in T1D patients.

In the thesis, we studied 1303 Caucasians with type 1 diabetes in the Diabetes Control and Complications Trial (DCCT). With the experience of diabetes study, many factors are associated with diabetes complications, they are age, gender, cohort, treatment, diabetes duration, body mass index (BMI), exercise, insulin dose, etc. We mainly focus on which factors are associated with total cholesterol (CHL) analysis in the thesis.

Many measures were collected monthly, quarterly or yearly for average 6.5 years from 1983 to 1993. We used annually lipid measures of DCCT because of their values are sufficient and complete, and they belong to longitudinal data.

Different methods are discussed in the study, and linear mixed effect models are the appropriate approach to the study. The details of model selection with CHL model analysis are shown, which includes fixed effect selection, random effects selection, and residual correlation structure selection. Then the SNPs were added on three models individually in GWAS. We found locus (rs7412) is not only genome-wide associated with CHL, but also genome-wide associated with LDL.

We will assess whether these SNPs are diabetes-specific in the future, and we will add dietary data in the three models to identify locus are associated with the interaction of diet and SNPs.

abstract: Master of Science (MSc)


title: Effect of Inhaled Corticosteroid on CT-derived Lung Density in an in vivo Allergic Inflammation Model

contributor:
Labiris, Renee
Health Sciences

subject: Asthma

subject: Budesonide

subject: BN Rat

subject: CT Imaging

subject: Densitometry

subject: Quantitative Histology

subject: Analytical, Diagnostic and Therapeutic Techniques and Equipment

subject: Animal Diseases

subject: Medicine and Health Sciences

subject: Respiratory Tract Diseases

abstract:
Allergic asthma is a disease involving airway inflammation, commonly linked to allergen exposure. Computed tomography (CT) is used to quantitatively assess changes in density, hence inflammation, in the lung. CT imaging provides the ability to non-invasively and longitudinally study disease progression and evaluate treatment efficacy. The objective of this study was to determine the sensitivity of CT to detect the anti-inflammatory effects of budesonide (BUD) by measuring airway tissue density in a rat model of allergic airway disease.

Female Brown Norway rats were exposed intratracheally to house dust mite (HDM) extract (250 µg in 100µL saline) or saline control every other day for a total of five administrations (inflammatory phase). ABUD dose and temporal response study was performed usingBUD 0, 10, 100, and 300 µg/kg administered concurrently with HDM for three and six treatments (treatment phase). CT scanning was performed at baseline, post inflammatory phase, and after three and six BUD treatments. From the CT, density was measured in a defined volume of interest surrounding the major airways. Bronchoalveolar lavage (BAL) and histological samples were collected at the same time points.

After the inflammatory phase, a significant increase in peribronchial density was found in the HDM group compared to controls. This corresponded to a significant increase in inflammation by histology andBALtotal cell count (TCC), specifically eosinophils. Within the treatment phase after three treatments,BUD100 and 300 µg/kg led to a significant shift in lung density compared to HDM exposure alone, to a state similar to baseline. All BUD treated groups expressed a significant reduction in peribronchial density after six treatments. However, histology andBALTCC only showed a significant decrease in inflammation after six treatments for all three BUD doses.

CT densitometry is a sensitive, non-invasive method of evaluating the anti-inflammatory effects of budesonide and can be used for future screening of therapies in allergic lung models. Airway segmentation of CT permits the localized assessment of peribronchial inflammation, while other outcome measurements, such as BAL cytology, provide whole lung assessment which may not accurately reflect important regional changes.

abstract: Master of Science (MSc)


title: The Role of Pavlovian Conditioned Inhibition in Avoidance Learning: An Extension and Revision of Two-Factor Avoidance Theory

contributor:
Siegel, S.
Psychology

subject: Psychology Psychology

abstract: This thesis surveys the avoidance conditioning literature of the past 30 years and discusses various theories of avoidance learning. The theory that has dominated the field has been the "two-factor avoidance theory". Two-factor theory proposes that avoidance learning is based on the interaction of Pavlovian and instrumental conditioning processes. It is shown how two-factor theory has evolved such that it can adequately handle a majority of experimental findings related to avoidance phenomena. An examination is then made of the role of Pavlovian conditioned inhibition in avoidance conditioning. Recent version of two-factor theory do not adequately account for inhibitory processes in avoidance learning. It is hypothesized that avoidance response-contingent feedback stimuli (FSs) become Pavlovian conditioned inhibitors over the course of avoidance training and that this inhibitory property provide the FS with the capacity to reinforce avoidance behavior. If the inhibitory property accruing to the FS is responsible for its reinforcing capabilities then two converging findings are expected. First, the inhibitory and reinforcing strengths of a FS should covary in a positive manner. A more effective (reinforcing) FS should show greater inhibitory strength at the end of avoidance training than a less effective FS. The results of Experiments 1 and 2 of this thesis confirm this prediction. Second, a pretrained Pavlovian conditioned inhibitor should function as a more powerful reinforcer of avoidance behaviour than non-inhibitory stimuli. Experiments 3 and 4 provide evidence supporting this prediction. The results of Experiment 1-4 taken together support the hypothesis that the conditioned inhibitory properties accruing to a FS are of functional significance for avoidance learning. On the basis of these findings, two-factor theory is revised so that it can account for inhibitory processes. This is done by incorporating Rescorla's contingency model of Pavlovian conditioning into Anger's recent version of two-factor avoidance theory. It is then shown how this revised version of two-factor theory offers a more viable account of avoidance learning than other current theories (e.g., positive reinforcement views, expectancy theories, etc.). It is also shown how revised two-factor theory can handle extinction phenomena once thought to be anomalous to a two-factor approach. Finally, Experiment 5 is designed to test a prediction derived from an extension of the "learned-safety" formulation: that repeated nonreinforced exposure of a FS prior to avoidance training endows the FS with true inhibitory or safety signal properties thus making it an effective reinforcer of avoidance behavior. It is found, contrary to the learned-safety hypothesis, that preexposing the FS retards subsequent avoidance conditioning. This result suggests that simple preexposure in the total absence of aversive events is not a sufficient condition for establishing a safety signal.

abstract: Doctor of Philosophy (PhD)


title: PHYSICS OF STRINGS AND EXTRA DIMENSIONS

contributor:
Burgess, Cliff
Physics and Astronomy

subject: extra dimensions

subject: string theory

subject: holography

subject: quantum Hall effect

subject: branes

subject: Condensed Matter Physics

subject: Elementary Particles and Fields and String Theory

subject: Condensed Matter Physics

abstract: The purpose of this thesis is twofold and motivated by recent developments in string theory and extra dimensional models. The first objective is to describe the development and progress in the codimension-2 brane paradigm as a potential cosmological scenario. Secondly, it presents the Antide Sitter/Conformal Field Theory (AdS/CFT) conjecture, also known as holography, as a tool for calculating physical quantities in condensed matter system and goes on to model the quantum Hall effect. We first describe the initial development of treating back-reaction in codimension-2 branes systems with a scalar and gauge field. The purpose of this is to examine the low-energy effective dynamics on the brane. Furthermore, applications are then explored for D7-branes in F-theory as well as D3-branes in large extra dimensional scenarios explored as a model for the cosmological constant problem. The result of this work is that the higher and lower dimensional scenarios are consistent with each other once brane back-reaction is considered in these models. This work led to a number of future works one of which is in relation to the cosmological constant problem. While the subsequent work is beyond the scope of this thesis, we present a picture and further references for the reader. The larger, later, portion of this thesis introduces the concept of holography, its origins, and the applicability to condensed matter systems. Furthermore, we discuss the applicability in particular to the quantum Hall effect (QHE) and present a model in the holographic language that correctly reproduces some of the physics of the QHE. This includes a paper in which we introduce the model, along with demonstration of symmetry properties and conductivity calculations, as well as a paper which examines the finite size scaling behaviour of the model. As a benefit to the reader, we present a `starter edition guide' to the AdS/CFT dictionary preceding these papers for non-experts such that this thesis is self-contained. The upshot is that these avenues of work, in particular quantum Hall-ography, have been very successful in modeling physics using tools originally developed by string theory. As such, it provides support for string theory as a model and framework, as well as providing more opportunities for future predictions of physical quantities.

abstract: Doctor of Philosophy (PhD)


title: Characterization and Reduction of Friction in a Hybrid Transmission

contributor:
Veldhuis, Stephen
Sklad, M. P.
Mechanical Engineering

subject:
Friction
Coatings
Tribology
Surface Engineering
Transmission
Gears
Tribology
Tribology

abstract:
The aim of this study was to explore environmentally friendly solutions to reduce the friction present in automotive transmissions.

A 2005 Ford Escape Hybrid transmission was used in this study to establish reasonable operating conditions for the gear surfaces.

Background on gear operation and surface interaction was studied to understand the nature of the contact between the gear surfaces. Based on this, a mathematical model of gear interaction was developed and used to bracket the loading conditions of the gear tooth interface to be up to 1.5GPa of contact pressure with 2m/s relative sliding velocity. This information was used to aid in the identification of suitable surface engineering technologies and set the operating conditions for reciprocating tribometer based measurements.

Additionally, tribological tests were performed on pin-on-disc samples which were treated with various surface treatments. The resulting wear surfaces were then studied using optical and Scanning Electron Microscopy (SEM) as well as Raman Spectroscopy. These techniques were used to better understand the mechanisms associated with wear and the role that the surface treatments played in reducing wear. Based on the testing performed, the best surface treatment for this application was a super finishing process. This process also met cost and environmental constraints. An in-house dynamometer was also developed to be used in the future full scale testing of a transmission.

abstract: Master of Applied Science (MASc)


title: Nuclear Magnetic Resonance Studies of Chemical Exchange in Solution and Simulation of Chemical Exchange in Rotating Solids

contributor:
Bain, Alex D.
Chemistry

subject: Chemistry Chemistry

abstract:
The primary objective of the following work is to advance the study of dynamic processes in molecules by Nuclear Magnetic Resonance. Rate measurements by NMR give rise to activation parameters of unprecedented accuracy. We have had much success with small molecules in solution phase and would like to extend these methods to larger molecules and to the solid phase.

Two studies into small molecules found: substantial entropies of activation for furfural in a series of solvents and that measured substituent effects on amide barriers could not be explained simply by Atoms in Molecules methodologies. Exchange rates measurements were made on two large sample systems: DADS which has five observable conformations, and TRH is proline-containing tripeptide with two conformations. Complete lineshape analysis and selective inversion experiments provided for reliable activation parameters.

Currently lineshape simulation methods for exchanging mUltispin systems undergoing magic-angle spinning using full theory are not available. Using the timeindependent Floquet approach it was possible to do such simulations. Since this method involves large matrices an efficient numerical method was developed. A sparse implementation of a stable formulation of the dual Lanczos algorithm made these simulations possible on a realistic time scale. The CPMAS spectra of doubly-¹³Clabelled dimethylsulfone were successfully simulated for a series of temperatures and rotor speeds.

abstract: Doctor of Philosophy (PhD)


title: FABRICATION AND CHARACTERIZATION OF A MEMS MAGNETOMETER FOR MEASURING TORQUE OF A MAGNETIC CRYSTAL

contributor:
Kleiman, Rafael
Luke, Graeme
Selvaganapathy, Ravi
Engineering Physics

subject:
microelectromechanical systems
torque magnetometry
frequency
stiffness
Engineering Physics
Engineering Physics

abstract:
With the advances in MEMS technology, the studies of the properties of magnetic crystals have reached the microscopic level. Critical information such as the magnetization and susceptibility of a magnetic sample can be obtained using a microtorque magnetometer, such as ones incorporating piezoresistive or capacitive detection that have been fabricated and tested by earlier research groups. This type of magnetic information is useful in the study of superconductivity, for example. The microtorque magnetometer designed and fabricated in this thesis has the potential of being used in this field of study.

This thesis describes the design, fabrication and testing of a capacitive microtorque magnetometer. By using ANSYS, a computer modelling program, an ideal model of the rotating microtorque magnetometer was devised. Fabrication involved testing a variety of procedures before establishing the successful and efficient method of building the microtorque magnetometer. A fifth order resonant mode was successfully detected during the testing stage. A method of studying the desired resonant mode has been devised and explained in the later chapters of this thesis.

abstract: Master of Applied Science (MASc)


title: Angular Dependence of the MatriXX Evolution

contributor:
Ostapiak, Orest
Diamond, Kevin
Farrell, Tom
Medical Physics

subject: IMRT

subject: VMAT

subject: MatriXX Evolution

subject: Angular Response

subject: Gantry Angle Dependent Correction Factors.

subject: Medicine and Health Sciences

subject: Physical Sciences and Mathematics

subject: Medicine and Health Sciences

abstract:
The purpose of this thesis is to explore the angular response to dose of the MatriXX Evolution, manufactured by IBA Dosimetry, a 2-dimensional ion chamber array used for patient specific quality assurance of advanced radiotherapy techniques such as IMRT and VMAT. Investigations were made to characterize the angular response of the MatriXX and describe any differences from the Philips Pinnacle3 Treatment Planning System (TPS) used at the Juravinski Cancer Centre.

A comparison was made between the gantry angle dependent correction factors supplied by the manufacturer and those derived by measurement. Gantry angle dependent correction factors were derived, with the MatriXX under 5cm polystyrene build-up and without any build-up, for the 5 x 5 cm2, 10 x 10 cm2 and 20 x 20 cm2 field sizes.

For gantry angles ranging from 320o to 40o the maximum difference between the derived gantry angle dependent correction factors and those provided by the manufacturer is 1.5%, at a gantry angle of 320o, a 5 x 5 cm2 field and without build-up. The differences for the 10 x 10 cm2 and 20 x 20 cm2 fields within this gantry angle range are less than 1%. Between gantry angles of 50o and 130o the largest difference is 4.9% at 100o, for the 5 x 5 cm2field without build-up. The other field sizes show similar differences; 4.7% at gantry angle of 120o for 10 x 10 cm2 with build-up and 4.0% at a gantry angle of 80o without build-up. Between gantry angles of 140o to 220o the greatest discrepancy is for the 5 x 5 cm2 field with build-up, a difference of 3.0%. The 10 x 10 cm2 has a maximum difference of 2.4% at gantry angles of 180o and 200o, both when the MatriXX has build-up. The maximum discrepancy for gantry angle dependent correction factors for the 20 x 20 cm2 fields is at a gantry angle of 140o, when the MatriXX has build-up. Between the gantry angles of 230o to 310o the largest discrepancy occurs between the derived gantry angle dependent correction factors and those supplied by the manufacturer. For the 5 x 5 cm2, 10 x 10 cm2 and 20 x 20 cm2 fields respectively the largest differences are 5.9%, 4.5% and 4.9%. All three occur when there is no build-up.

abstract: Master of Science (MSc)


title: Plasticity of Face Processing in Children and Adults

contributor:
Maurer, Daphne
Trainor, Laurel
Rutherford, Mel
Psychology

subject: faces; recognition; training; development; chimpanzee

subject: Developmental Psychology

subject: Developmental Psychology

abstract: To assess how the plasticity of the face processing system changes with age, we trained 8-year-olds, 10-year-olds, and adults to differentiate 10 chimpanzee faces at the individual level for 3 days by having them watch a child-friendly training video. Their improvement from baseline was compared to that of age- and gender-matched controls who completed the pre- and post-tests, but did not complete training. Improvement did not vary across age: 8-year-olds, 10-year-olds, and adults all showed similar improvement in accuracy at discriminating the 10 chimpanzee faces on which they were trained. This improvement resulted in the reduction of the own-species bias after training. However, the benefits of training did not generalize to novel exemplars. In addition, participants from both the training and control groups showed a practice effect: their accuracy at discriminating both chimpanzee and human faces improved from pre- to post-test. Taken together, these results demonstrate that the face processing system is somewhat plastic between 8 years of age and adulthood and suggest that this plasticity remains stable throughout this period of development.

abstract: Master of Science (MSc)


title: Design & Fabrication of Microfluidic DNA Extraction Device for Water Quality Monitoring

contributor:
Selvaganapathy, P. R.
Mechanical Engineering

subject: DNA extraction

subject: DNA purification

subject: water monitoring

subject: microfluidic

subject: polystyrene self-assembly

subject: macro/meso porous silica monolith structure

subject: Biochemistry, Biophysics, and Structural Biology

subject: Biomedical Engineering and Bioengineering

subject: Biotechnology

subject: Cell and Developmental Biology

subject: Chemical Engineering

subject: Materials Science and Engineering

subject: Mechanical Engineering

subject: Microbiology

subject: Nanoscience and Nanotechnology

subject: Public Health

abstract:
Continuous monitoring of pathogens that may be present in water is one of the key preventive measures that can be used in rural areas of developed countries and developing countries to reduce chances of the water borne diseases outbreak. Off-site testing of microbiological contamination of water is conventionally done for monitoring water quality. However, such a process is time consuming and involves using a variety of hazardous reagents. To address these issues, a portable device for rapid detection of unsafe water is needed.

One of the key components in this system is to extract DNA from the pathogens. The primary consideration for DNA extraction is to separate DNA from proteins and other cell debris in the lysate solution. The pure population of DNA molecules are then sent downstream for subsequent processing such as real-time PCR (Polymerase Chain Reaction) and BioFET sensors for further identification and analysis.

The focus of the thesis will be on the fabrication of a microfluidic DNA extraction system that can achieve high DNA extraction efficiency and a good repeatability. It can also be easily automated, and integrated with other components of the DNA analysis system. The high surface-to-volume macro/mesoporous silica DNA binding column was synthesized using sol-gel silica technology and triblock copolymer F127 was added to form a crack-free mesoporous silica network. Furthermore, a monodispersed polystyrene microspheres soft-template was assembled using a simple but novel technique that employs controlled suction to enhance self-assembly into a periodically patterned structure in the extraction chamber/chambers. In combination of heat annealing treatment of this assembled polystyrene template, one can easily control the size of the macropores in the final macro/mesoporous silica structure to allow a lower pressure resistance for DNA sample flow at elution stage. The final macro/mesoporous silica structure synthesized using heat annealing temperature of 115oC for 10 minutes was determined to have a porosity of 83.6%. Mesopores of this silica monolith was determined by BET test to be 3.65 nm and the macroporous ranging from 0.5μm to 0.86μm were observed. In addition, the fabrication of porous silica monolith can be easily integrated with the microfluidic system for achieving DNA extraction purposes

abstract: Master of Applied Science (MASc)


title: ISAAC: AN IMPROVED STRUCTURAL ANNOTATION OF ATTC AND AN INITIAL APPLICATION THEREOF

contributor:
Dushoff, Jonathan
Brian Golding, Paul Higgs
Biology

subject:
bioinformatics
genetics
genomics
computational biology
bacteria
horizontal gene transfer
Bioinformatics
Bioinformatics

abstract: We introduce new software (ISAAC: Improved Structural Annotation of attC) to annotate cassette arrays in bacterial integrons by ﬁnding attI and attC sites, and to provide detailed annotation of the attC sites for analysis. We demonstrate an initial application of ISAAC by annotating the cassette complements of all the integrons we identiﬁed in the RefSeq bacterial genome database, and providing an analysis of the patterns of nucleotide frequencies at the structurally important positions in the attCs we’ve found.

abstract: Master of Science (MSc)


title: The Autonomy of the City: Re-Imagining Political Belonging and Agency

contributor: Political Science - International Relations

subject:
Cities
MV Sun Sea
International Relations
Migration
Autonomy
International Relations
International Relations

abstract:
This dissertation examines the apparently conflicting dynamics of movement and control. It does so by taking a unique approach to exploring these dynamics of movement and control by de-centering the state as the assumed site of authority of such dynamics. While traditional IR approaches situate the state as the authority for controlling and facilitating movement across borders, this study – which focuses on the movement of refugees and asylum seekers – de-stabilizes that authority by considering the ways in which other actors and spaces influence and resist these dynamics. Specifically, I consider the ways in which cities and migrants themselves might shape the apparently ‘global’ or ‘state’ processes of determining who enters and belongs in a particular political community. By de-centering – but not dismissing – the authority of the state in these matters, it becomes evident that definitions of political community are not only highly ambiguous but also somewhat autonomous from the state. The city emerges as a fundamentally different sort of political space from the state. The city – though not separate from the state – exceeds the state and opens up different possibilities for belonging politically than those made possible by ‘seeing like a state’

These theoretical issues are contextualized in this study through the case study of the MV Sun Sea, a ship which arrived off the coast of Vancouver Island, Canada in August 2010 carrying 490 Sri Lankan asylum seekers. This case is explored from three angles – ‘seeing like a state’, ‘seeing like a city’, and ‘seeing like a refugee’ – in order to consider the dynamics of movement and control and the ways in which the autonomies of cities and migrants themselves reshape political space and subjectivities.

abstract: Doctor of Philosophy (PhD)


title: Composed in Darkness: Trauma and Testimony in Seamus Heaney's North

contributor:
O`Connor, Mary
Donaldson, Jeffrey
Kehler, Grace
English and Cultural Studies

subject:
Heaney
North
Ireland
Trauma
Testimony
Troubles
Literature in English, British Isles
Literature in English, British Isles

abstract:
This thesis examines how Seamus Heaney’s North attempts to bear witness to the prolonged political conflict in Ireland known as the Troubles. Drawing upon the intersecting discourses of trauma and testimony as theorized by Cathy Caruth, Shoshana Felman and Dori Laub, it argues that North operates as an experimental enterprise evaluating diverging methods of poetically representing and working through the experience of trauma. Though these methodologies seek to convey the Irish Troubles, neither is wholly effective and both are ultimately eschewed by the poet.

My first chapter examines Part I and the invocation of representative models—which are at times historical, imaginative and mythical—in order to render legible the experience of trauma. I suggest that the poem’s invocation of human remains exhumed from Jutland bogs as one such model may not be ethical and then read this representation within a broader sense historiographical writing supplied by Michel de Certeau’s The Writing of History. My second chapter looks at Part II and the poet’s assertion of an autobiographical “I” in order to engage directly with the Troubles. I read this part of the collection primarily as a meditation on the limitations of community and poetry, which undercuts the poet’s attempt to deliver testimony. In my conclusion, I suggest Heaney’s testimonial enterprise may not fulfill its whole potential because of its publication in the midst of the Troubles, which forecloses the possibility of futurity, a criticism which may not hold true for the poet’s later collections.

abstract: Master of Arts (MA)


title: Karst Hydrogeology and Geomorphology of the Sierra de El Abra and the Valles-San Luis Potosí Region, México

contributor:
Ford, Derek C.
Geology

subject: Geology Geology

abstract:
The general objective of this work was to develop a basic understanding of the karst hydrology, the nature and origin of the caves, the water chemistry, the surface geomorphology, and relationships among these aspects for a high relief tropical karst region having a thick section of limestone. The Valles-San Luis Potosí region of northeastern México, and in particular, the Sierra de El Abra, was selected for the study. A Cretaceous Platform approximately 200 km wide and 300 km long (N-S) delimits the region of interest. A thick Lower Cretaceous deposit of gypsum and anydrite, and probably surrounded by Lower Cretaceous limestone facies, is overlain by more than 1000 m of the thick-bedded middle Cretaceous El Abra limestone, which has a thick platform-margin reef. The Sierra de El Abra is a greatly elongated range along the eastern margin of the Platform. During the late Cretaceous, the region was covered by thick deposits of impermeable rocks. During the early Tertiary, the area was folded, uplifted, and subjected to erosion. A high relief karst having a wide variety of geomorphic forms controlled by climate and structure has developed. Rainfall in the region varies from 250-2500 mm and is strongly concentrated in the months June-October, when very large rainfalls often occur.

A number of specific investigations were made to meet the general objective given above, with special emphasis on those that provide information concerning the nature of ground-water flow systems in the region. Most of the runoff from the region passes through the karstic subsurface. Large portions of the region have no surface runoff whatsoever. The El Abra Formation is continuous over nearly the whole Platform, and it defines a region of very active ground-water circulation. Discharge from the aquifer occurs at a number of large and many small springs. Two of them, the Coy and the Frío springs group, are among the largest springs in the world with average discharges of approximately 24 m³/sec and 28 m³/sec respectively. Most of the dry season regional discharge is from a few large springs at low elevations along the eastern margin of the Platform. The flow systems give extremely dynamic responses to large precipitation events; floods at springs usually crest roughly one day after the causal rainfall and most springs have discharge variations (0max/0min) of 25-100 times. These facts indicate well-developed conduit flow systems.

The hydrochemical and hydrologic evidence in combination with the hydrogeologic setting demonstrate the existence of regional ground-water flow to several of the large eastern springs. Hydrochemical mixing-model calculations show that the amount of regional flow is at least 12 m³/sec, that it has an approximately constant flux, and that the local flow systems provide the extremely variable component of spring discharge. The chemical and physical properties of the springs are explained in terms of local and regional flow systems.

Local studies carried out in the Sierra de El Abra show that large conduits have developed, and that large fluctuations of the water table occur. The large fossil caves in the range were part of great deep phreatic flow systems which circulated at least 300 m below ancient water tables and which discharged onto ancient coastal plains much higher than the present one. The western margin swallet caves are of the floodwater type. The cave are structurally controlled.

Knowledge gained in this study should provide a basis for planning future research, and in particular for water resource development. The aquifer has great potential for water supply, but little of that potential is presently used.

abstract: Doctor of Philosophy (PhD)


title: In-Vivo X-Ray Fluorescence Assessment of Iron Levels in the Skin for β-Thalassemia Patients

contributor:
Farquharson, Michael
McNeill, Fiona
Bock, Nicholas
Medical Physics

subject:
X-Ray
Fluorescence
XRF
Skin
Thalassemia
Medical Biophysics
Medical Biophysics

abstract: The purpose of this study is to assess the feasibility of a non-invasive, reliable, and cheap method to evaluate iron-overload in beta-thalassemia major patients. The approach taken was through the possibility of in-vivo measurement of iron in the skin using a technique called x-ray fluorescence. It was hoped that the quantification of iron levels in the skin will correlate with those levels in major parenchymal organs, such as the liver and the heart – where most iron deposition occurs in thalassemic patients. Water phantoms were used to produce a calibration line with an R2 value of 0.998. Skin, liver and heart tissues from 36 control mice were measured and their iron levels quantified. Iron concentration range in the skin was found to be -2 – 38 ppm with an average of 9.8 ± 1.6 ppm. Significant correlation was found between the iron levels in skin vs. heart (Rs2 of 0.382); however, it was not significant in skin vs. liver (Rs2 of 0.080). Skin biopsies from various sites of 6 cadavers were investigated in a synchrotron light source facility. Maps of iron, zinc and calcium distribution as a function of skin depth were then constructed. It was found that all three elements were significantly present in the epidermal layer compared to the dermal one. Calcium and zinc were present in the entire epidermis, whereas iron was mainly concentrated at the deepest region of the epidermis. It was also concluded that skin samples from the back, arm and thigh gave the clearest elemental distribution.

abstract: Master of Science (MSc)


title: THE IDENTIFICATION AND DIFFERENTIATION BETWEEN NORMAL AND SECONDARY COLORECTAL CANCER IN HUMAN LIVER TISSUE USING X-RAY INTERACTION TECHNIQUES

contributor:
Farquharson, Michael J
Medical Physics

subject:
XRF
Coherent Scatter
Normal tissue
Tumour tissue
Trace elements
Multivariate analysis
PCA
SIMCA
Medical Biophysics
Medical Biophysics

abstract:
As secondary colorectal liver cancer is the most widespread malignancy in patients with colorectal cancer, the main aim of this study is to identify and differentiate between benign and malignant secondary colorectal liver cancer tissue. Low energy X-ray interaction techniques were used. XRF and coherent scattering data were collected for all 24 normal and 24 tumour matched pair tissues. Measurements of these parameters were made using a laboratory experimental set-up comprising a Mo X-ray tube, Si Drift detector and Scintillation (NaI) detector.

Twelve elements of interest were statistically explored for normal and tumour samples. Comparing normal and tumour tissues, statistically significant differences have been determined for K, Ca, Cr, Fe, Cu, Zn, Br and Rb. However, for P, S, As and Se, no statistically significant differences have been found.

Coherent scatter profiles were collected and fitted for all the samples and three peaks were observed at momentum transfer values: adipose peak: 1.1 nm-1, fibrous peak: 1.6 nm-1 and water content peak: 2.2 nm-1. The Amplitude, FWHM and area under these peaks were statistically analysed. These parameters were found to be significantly higher in secondary colorectal liver tumour compared to surrounding normal liver tissue for both fibrous and water content peaks. However, no significant differences were found for adipose peak parameters.

Multivariate analysis was performed using the XRF, coherent scatter and elemental ratios data separately and the accuracy of classification results of 20 unknown samples was found. However when all the variables were combined together, the classification models were improved. This study has shown that the XRF and coherent scatter data of normal and secondary colorectal liver cancer are statistically different and the combination of these variables in multivariate analysis has the potential to be used as a method of distinguishing normal liver tissue from the malignant tumour tissue.

abstract: Master of Science (MSc)


title: Function and distribution of neuronal high-affinity IgE receptors (FcεRI)

contributor:
Bienenstock, John
Kunze, Wolfgang
Karimi, Khalil
Neuroscience

subject:
IgE
FcεRI
SCG
allergy
high-affinity IgE receptor
Molecular and Cellular Neuroscience
Molecular and Cellular Neuroscience

abstract:
Background

IgE antibodies have high antigen specificity and are the hallmark biomarkers of allergy. IgE binds to high-affinity IgE receptors, known as FcεRI, which are expressed especially on mast cells and basophils. In allergic individuals, antigen binding to IgE that is associated with FcεRI leads to crosslinking of adjacent receptors and subsequently to cell activation, degranulation and/or secretion of bioactive molecules. These molecules together cause minor local tissue reactions such as oedema or itch, but also can cause major systemic reactions such as hypotension, cardiac and respiratory distress or even laryngeal swelling and death. The role of the nervous system in these reactions is usually thought of as secondary. However, in recent years there have been a number of studies suggesting the expression of FcεRI on neurons, opening the possibility that nerves are directly involved in antigen-specific responses and making a previously unrecognized contribution to allergic disease.

Based on these previous observations regarding neuronal FcεRI, the current study employed both in vivo and in vitro approaches with the following objectives:

To confirm the presence of FcεRI on peripheral nerves and demonstrate that they are functionally active under different conditions of IgE sensitization.

To examine the pathways involved in neuronal activation by IgE bound to FcεRI and compare and contrast these to those already established for mast cells and basophils.

Methods and Results

A potential role of neuronal FcεRI in the IgE-dependent allergen avoidance behaviour of sensitized mice presented with antigen in sucrose solution was assessed based on published evidence for the involvement of peripheral nerves in this response.

Chimeric mice with a wild-type nervous system but lacking FcεRI on hematopoietic cells including mast cells and basophils, failed to exhibit aversive behaviour, whereas mice with FcεRI-bearing hematopoietic cells demonstrated the normal aversive response confirming that FcεRI expression on mast cells is necessary for development of allergen avoidance. While immunohistochemical staining could detect IgE bound to mast cells in tissue samples, no IgE was detected on nerves where the nerves were identified by using a pan-neuronal marker, PGP 9.5, in the intestine of either normal or passively sensitized C57BL/6 and BALB/c mice. Similarly, traditional FACS analysis clearly identified FcεRI on cultured mast cells, but these methods provided no evidence for expression of FcεRI or IgE binding on superior cervical ganglion (SCG) and dorsal root ganglion (DRG) neurons in culture.

To determine evidence for functional FcεRI on neurons in vitro, intracellular calcium increase was assessed as a measure of cell activation following sensitization and antigen challenge. Using both microscopy and FACS analysis, calcium fluorophore (Fluo-3, AM) increase could be detected in SCG or DRG that were activated with the calcium ionophore A23187 but not following antigen challenge.

Summary: The current study found no evidence for the presence of the FcεRI on neurons in situ or their sensitization by IgE actively or passively using several different approaches both in tissues and cultured SCG or DRG neurons. Possible explanations for the resultant discrepancy with previously published works are discussed.

abstract: Master of Science (MSc)


title: WAX-BASED EMULSIFIERS FOR USE IN EMULSIONS TO IMPART WATER REPELLENCY TO GYPSUM WALLBOARDS

contributor:
Zhu, Shiping
Chemical Engineering

subject:
polymer
maleation
wax
alpha-olefin
maleic anhydride
Polymer Science
Polymer Science

abstract: Maleation is a common means of modification for many commodity polymers and is used to several ends. In this study, various waxes were functionalized with maleic anhydride through several maleation processes, with the end goal of obtaining a cost effective processes to make emulsifiers to be used in emulsions that impart water-resistance to building products, such as gypsum wallboards. Research was done in collaboration with an industrial partner, in order to replace commercially available emulsifiers currently being used in their processes with a less costly product that could easily be made on-site based on their consumption requirements, through a solvent-free approach. Reactions involving both the free-radical initiated maleation of paraffin waxes and thermal addition of maleic anhydride to alpha-olefins were examined extensively. It was found that emulsions with properties matching or exceeding those of control emulsion formulations were obtainable using experimental emulsifiers made through both maleation methods. When used in gypsum wallboards, emulsifiers made through thermal maleation showed levels of water-repellency that matched or exceeded those of control formulations at lower loading levels, while emulsifiers made through free-radical maleation were subject to performance issues.

abstract: Master of Applied Science (MASc)


title: DEVELOPMENT OF A MONTE CARLO SIMULATION TOOL FOR LIGHT TRANSPORT INSIDE SCINTILLATION CRYSTALS

contributor:
Peng, Hao
Farrell, Thomas
Kevin Diamond, Soo-Hyun Byun
Medical Physics

subject:
positron emission tomography
Monte Carlo simulation
Scintillation Crystals
Optics
Medical Biophysics
Medical Biophysics

abstract: The scintillation crystal is a critical component in positron emission tomography (PET) systems. It impacts a number of PET system performance parameters, including spatial, energy, and time resolution. Our goal is to develop a new simulation tool to achieve improved accuracy by addressing several limitations in the existing packages, including more advanced surface treatments, temporal dependency of photon arrival, and rigorous experimental validations. The comparison of preliminary Monte Carlo simulation results and analytical calculations for specular reflection suggest that the simulation model is working well. The time-resolved light output was studied for various crystal surface treatment configurations. The measured energy resolutions are in the range of approximately 10% to 15%, which are in good agreement with published literatures. Based on the simulation and experimental results, the polished surface treatment, used together with an external specular reflector, is able to provide the best energy resolution and timing resolution for a LYSO (3x3x20 mm3) and SiPM assembly we tested. The AsCut surface with external diffusion reflector is not desired due to its inferior energy and timing resolutions. The direction and recommendation of improvements of simulation regarding surface models and wavelength dependency, as well as potential optimization of experiment such as timing pickoff methods, are discussed.

abstract: Master of Science (MSc)


title: ADOPTION AND USAGE OF ELECTRONIC MEDICAL RECORDS IN CANADIAN FAMILY PRACTICE: ARE SMALL PRACTICES AT A DISADVANTAGE?

contributor:
Archer, Norman P.
Howard, Michelle
Tan, Joseph
Global Health

subject: EMR

subject: Electronic Medical Records

subject: Primary Care

subject: Family Physician

subject: Small Practice

subject: Community Health and Preventive Medicine

subject: Databases and Information Systems

subject: Health and Medical Administration

subject: Health Policy

subject: Health Services Administration

abstract: Canadian primary care practices lag behind their counterparts in the United States and Europe in adopting Electronic Medical Record (EMR) systems to facilitate care. Although there is a considerable volume of cross-national conceptual literature focused on system design and barriers to adoption, there is little in the way of research on the unique problems faced by Canadian physicians within the publicly financed and privately provided system of healthcare delivery. This study uses a survey of Canadian physicians to investigate differences in perceptions of EMR value between two groups who have implemented these systems: “small practice” physicians, i.e. those with a maximum of 2 full-time physicians and “large practice” physicians, or those with three or more full-time physicians. A Mann-Whitney U Test conducted on survey item responses of the two groups finds that “small practice” physicians feel significantly less positive about EMRs with regards to ease of use, time savings and effective patient management.

abstract: Master of Science (MSc)


title: Quantifying the Direct and Indirect Effects of Dissolved Organic Matter (DOM) on Aquatic Organisms: Interaction with pH and Quality Measures

contributor:
Wood, Chris
Biology

subject: Dissolved organic matter (DOM)

subject: Daphnia magna

subject: Zebrafish

subject: Biotic Ligand Model (BLM)

subject: Sodium metabolism

subject: Ammonia and urea excretion

subject: Biology

subject: Pharmacology, Toxicology and Environmental Health

subject: Physiology

subject: Biology

abstract: Dissolved organic matter (DOM) in natural waters is a heterogeneous mixture of organic molecules with direct and indirect influences on aquatic organisms. Although the influences are usually attributed to DOM quantity (quantified as Dissolved Organic Carbon, DOC), the role of quality (optical and binding characteristics obtained by absorbance and fluorescence spectroscopy and potentiometric titration, respectively) is not well-understood. Through an initial critical review of the literature, followed by experimental geochemical, toxicological, and physiological investigations, a number of conclusions were reached that improve our knowledge in this area. Freshwater DOM sources exhibit source-dependent protection against metal toxicity, in particular copper (Cu). Generally, for this indirect effect, optically-dark terrestrially-derived or allochthonous DOMs offer better protection than microbially-derived or autochthonous sources. Linear regressions revealed that the better ameliorative effect is principally related to a higher aromatic composition (specific absorption coefficient, SAC340) and a greater humic-like fluorescent component as quantified by parallel factor analysis (PARAFAC). In addition, the allochthonous DOMs were shown to have relatively higher magnitudes of titration index (TI), a new summary of chemical reactivity of DOM molecules obtained by titration analysis, and closely related to optical properties. TI was strongly correlated with SAC340, suggesting greater binding capacities for DOM molecules with higher SAC340. Consequently, a method for incorporation of SAC340 as a DOM quality measure into the Biotic Ligand Model (BLM) was developed which improved Cu toxicity predictions in experimental tests with natural DOMs. For direct effects, two basic physiological functions (Na+ metabolism and nitrogen excretion) of the adult water flea (Daphnia magna, a cladoceran crustacean) and the zebrafish (Danio rerio, a teleost fish) were investigated at circumneutral and acidic pH (≥ 7 and ~ 5, respectively). Three previously characterized, chemically-distinct natural DOM sources as well as a commercial humic acid (AHA) were examined. Regardless of the pH conditions, while Na+ regulation of D. magna remained unaffected by the presence of all DOMs, the passive diffusive efflux of Na+ in zebrafish was attenuated, indicating ameliorative action against unidirectional Na+ loss. In addition, only a distinct allochthonous-autochthonous DOM source stimulated the Na+ uptake rate of zebrafish at low pH. Ammonia excretion rates of D. magna were reduced at circumneutral pH by the most highly coloured, allochthonous DOM, and at low pH by all three natural DOMs. Both in D. magna and in D. rerio, urea excretion rates at both pH conditions were not influenced by the presence of the various DOMs, and the same was true for ammonia excretion in the zebrafish. A commercially prepared humic acid (Aldrich humic acid, AHA) exerted anomalous actions relative to those of natural DOMs, and does not appear to be representative of their normal effects. In contrast to the actions of DOM in detoxifying metals, these direct effects of DOMs on freshwater organisms appeared highly unpredictable with variable dependencies on the source, pH and species. This thesis has advanced our understanding of the relationships between DOM quality and its indirect and direct effects on aquatic organisms, and points to new directions for future work.

abstract: Doctor of Philosophy (PhD)


title: THE ENTANGLEMENT ENTROPY NEAR LIFSHITZ QUANTUM PHASE TRANSITIONS & THE EMERGENT STATISTICS OF FRACTIONALIZED EXCITATIONS

contributor:
Lee, Sung-Sik
Erik Sorensen, Duncan O'Dell
Physics and Astronomy

subject:
entanglement entropy
lifshitz
quantum phase transitions
fermi surface
topology
fractionalization
Condensed Matter Physics
Quantum Physics
Condensed Matter Physics

abstract:
In Part I, the relationship between the topology of the Fermi surface and the entanglement entropy S is examined. Spinless fermionic systems on one and two dimensional lattices at fixed chemical potential are considered. The lattice is partitioned into sub-system of length L and environment, and the entanglement of the subsystem with the environment is calculated via the correlation matrix. S is plotted as a function of the next-nearest or next-next nearest neighbor hopping parameter, t. In 1 dimension, the entanglement entropy jumps at lifshitz transitions where the number of Fermi points changes. In 2 dimensions, a neck-collapsing transition is accompanied by a cusp in S, while the formation of electron or hole-like pockets coincides with a kink in the S as a function of the hopping parameter. The entanglement entropy as a function of subsystem length L is also examined. The leading order coefficient of the LlnL term in 2 dimensions was seen to agree well with the Widom conjecture. Of interest is the difference this coefficient and the coefficient of the term linear in L near the neck-collapsing point. The leading order term changes like |t-tc|1/2 whereas the first sub-leading term varies like |t-tc|1/3, where tc is the critical value of the hopping parameter at the transition.

In Part II, we study the statistics of fractionalized excitations in a bosonic model which describes strongly interacting excitons in a N-band insulator. The elementary excitations of this system are strings, in a large N limit. A string is made of a series of bosons whose flavors are correlated such that the end points of a string carries a fractionalized flavor quantum number. When the tension of a string vanishes, the end points are deconfined. We determine the statistics of the fractionalized particles described by the end points of strings. We show that either bosons or Fermions can arise depending on the microscopic coupling constants. In the presence of the cubic interaction in the Hamiltonian as the only higher order interaction term, it was shown that bosons are emergent. In the presence of the quartic interaction with a positive coupling constant, it was revealed that the elementary excitations of the system possess Fermion statistics.

abstract: Master of Science (MSc)


title: The Performance of Non-Impaired Tamil-English Bilinguals on the Bilingual Aphasia Test

contributor:
Moro, Anna
Cognitive Science of Language

subject: Tamil-English; Bilingual Aphasia Test; Non-Impaired

subject: Health and Medical Administration

subject: Rehabilitation and Therapy

subject: South and Southeast Asian Languages and Societies

subject: Health and Medical Administration

abstract: This thesis examines the performance of non-impaired Tamil-English speaking bilinguals on the Tamil-English version of the Bilingual Aphasia Test (BAT) (Paradis and Libben, 1987). The test was administered to 25 participants, 15 women and 10 men. The results show that, on average, participants achieved an overall score of 97%. However, participants did not do well on two subtests on the English version, specifically sections on derivational morphology and morphological opposites. Also, a more detailed analysis indicates that years of education significantly correlates with performance, even though it is claimed that years of education should not affect performance on this test. This study makes suggestions for how to improve the Tamil-English version, in view of the findings from this study, and provides a cautionary note on the role played by years of education in test performance. If the latter factor is not taken into account, the test could possibly lead to an inaccurate assessment of a patient’s language abilities, and could potentially result in misdiagnosis. In an effort to increase the test’s validity and reliability, this study recommends a series of modifications to the Tamil-English version of the BAT, based both on participants’ comments and on statistical analyses.

abstract: Master of Science (MSc)


title: Positivism Beyond the Hartian Pale

contributor:
Waluchow, Wilfrid
Sciaraffa, Stefan
Igneski, Violetta
Philosophy

subject:
H.L.A. Hart
legal positivism
analytic jurisprudence
philosophy of law
constitutional law
Joseph Raz
Legal History, Theory and Process
Other Law
Other Philosophy
Legal History, Theory and Process

abstract: This dissertation offers a critical analysis of the dominant philosophical theory of law today: Hartian positivism. The arguments proffered are not meant to strike at the underlying methodology of that account. Rather, they are intended to demonstrate that it performs sub-optimally with regard to its own jurisprudential aspirations. More specifically, this thesis contends that the Hartian position is unable to model the law in a way that captures the de facto terms of institutional governance, while also being able to give due theoretical credence to the normative structures and mechanisms that are widely deployed to regulate it. With this conclusion in hand, a new theory of law is suggested – one that seeks to stay true to the methods and aspirations of its predecessor, but which has been constructed so as to surpass its descriptive-explanatory capabilities. In this way, the following dissertation means to push analytic jurisprudence beyond the Hartian pale, and into new areas of theoretical discourse.

abstract: Doctor of Philosophy (PhD)


title: Fluid Dynamic Evaluation in Models of Arterial Branches

contributor:
Round, G. F.
Feuerstein, I. A.
Mechanical Engineering

subject:
Mechanical Engineering
Mechanical Engineering

abstract:
The purpose of this investigation is to determine experimentally the fluid dynamic field in models of arterial branching vessels and to identify the flow features which might influence the predominant occurrence of atherosclerotic lesions in such vessels.

Flow conditions in four rigid-walled models representing the aortic bifurcation, iliac bifurcation, mesentric artery branch and renal artery branch are investigated over a Reynolds number range of 1000-4000 and a complete range of flow division between daughter vessels. Qualitative flow streamline patterns and quantitative definition of those flow conditions leading to flow separation are determined primarily at steady flow with a limited set of pulsatile experiments. The flow patterns observed are photographed using high speed cinephotography and a neutrally-buoyant tracer-particle technique. The flow streamline patterns in the four models are complicated and characterized by secondary flow motion. This motion is accentuated with increasing Reynolds number. Flow separation is inducible through alteration of flow division between daughter vessels or by an increase in the flow rate. Each of the four models has distinct combinations of flow rate and flow division ratio which give flow separation at the outside wall of one or both daughter tubes. The separated flows observed here display streamlines forming an open vortex with flow entering and leaving. The site of the separation point in the branching plane is approximately constant with the reattachement points occuring further downstream as Reynolds number increases and as the branch flow rate decreases.

Shear rate distributions at the walls of the four models are measured using an electrochemical technique. This technique is based on an oxidation-reduction reaction at electrodes implanted in the wall. Distribution of wall shear rate of the branching site is very non-uniform, with high shear rate at the leading edge of the flow dividers. The shape of the shear rate curves are functions of the geometry, total flow rate and most importantly the flow division ratio. An unstable pattern of shear is found at the wall where separation is expected to occur. For pulsatile flow, the time-averaged rate of shear is not appreciably changed by frequency and amplitude of pulsation. The biological implication of the results is discussed with specific reference to the sites of atherosclerotic lesions found in man for these geometries.

abstract: Doctor of Philosophy (PhD)