title: Spatial distribution and preservation of carbon isotope biosignatures in freshwater microbialite carbonate

contributor:
Slater, Greg F.
Earth and Environmental Sciences

subject: biosignatures microbialites carbonate isotopes photosynthesis preservation astrobiology geochemistry

abstract: Modern microbialites provide the opportunity to explore the influences of biology on microbialite formation and understand how biosignatures can be preserved in these structures. In this study, we compared δ13Ccarb values from nodule and surface biofilm carbonates on microbialite structures across depths and locations throughout Pavilion Lake to evaluate whether variable light exposure produced limitations to biosignature formation. At depths below 21 m, vertical profiling of δ13Ccarb across colour transitions of surface biofilm on microbialite structures was performed to identify spatial arrangement of autotrophic and heterotrophic biosignatures. Finally, preservation of the photosynthetic biosignature over time was investigated by collecting carbonates beneath the microbialite surface. These investigations were performed in order to better characterize the factors controlling biosignature formation, distribution, and preservation within Pavilion Lake.Decreasing trends of δ13Ccarb with depth across study sites indicated that attenuated sunlight in the water column is likely the primary control on biosignature formation. Below 21 m, photosynthetic enrichments representing biosignatures on microbialite surfaces were reduced and recorded δ13Ccarb values that fell within the predicted equilibrium range. Biosignature loss is suggested to result from the relative proportions of autotrophic and heterotrophic processes changing at depths and producing average δ13Ccarb values. Variability of where biosignatures are lost on the microbialite surface indicated that the spatial extent of photosynthetic communities producing enrichments is potentially influenced by variable incidences of light at these depths. Although no definitive biosignatures of heterotrophy were identified, several interfaces were identified where the balancing proportions of autotrophic and heterotrophic processes influenced by light variability potentially mediate biosignature loss. Decreasing trends of δ13Ccarb beneath the microbialite surface and estimates of past microbialite growth rates indicated that surface biosignatures are lost within 100 – 400 years. It is suggested that infilling processes overprint enrichments and deplete δ13Ccarb values due to heterotrophic abundance below the microbialite surface. This is supported by an isotopic mass balance that predicts smaller inputs of heterotrophically-depleted DIC are required to sufficiently overprint δ13Ccarb enrichments. These results concluded that the photosynthetic biosignature identified in Pavilion Lake is short-lived and mitigated by biological processes.

abstract: Thesis

abstract: Master of Science (MSc)


title: Resident Remediation: Processes and Outcomes over a 16-year period at McMaster University

contributor:
Dore, Kelly
Health Science Education

subject: resident remediation university McMaster

abstract: Resident remediation is often guided at the residency program level, however some institutions also have designated bodies within their departments of postgraduate medicine for this purpose, such as the Educational Advisory Board (EAB) at McMaster University. Research from the postgraduate department level has been limited, and this study aims to better understand remediation in postgraduate training with two primary objectives: 1) to review remediation processes and practices at McMaster University, from the standpoint of the postgraduate medical Education Advisory Board (EAB), and 2) to describe the characteristics and relevant outcomes for residents who underwent remediation at McMaster.  A total of 85 residents were suitable for analysis and the majority of these residents were international medical graduates (62%). Most had knowledge or medical expert weaknesses (92%) while 51% of residents had behavioural (e.g. professionalism, communication) weaknesses, and a total of 42% of residents had both. A number of residents (25%) had a serious coexistent medical or psychosocial factor that contributed to the need for remediation. Remediation strategies were better described for knowledge weaknesses than for behavioural weaknesses, and there was more consistency in the remediation strategies used for knowledge weaknesses. The most commonly implemented strategies for remediation of behavioural weaknesses involved using resources that were external to the department of postgraduate medicine. The majority of residents completed their training programs at 71%. None of the analyzed predictors were found to be statistically significant for program completion, however this study was underpowered to find such predictors given the convenience sample size. This study represents the most comprehensive review of resident remediation at a single institution and it underscores the need for improved documentation and review of remediation practices at institutions. It also raises important questions regarding the effectiveness of remediation and it highlights the critical nature of accurately diagnosing a learner’s deficiencies and providing targeted remediation strategies.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Residency training is an apprenticeship period that follows the completion of medical school. It prepares doctors for independent practice within the chosen discipline or specialty of medicine. Some residents struggle during this period and need additional training time and help in order to improve their skills to become safe and effective doctors. It is not always immediately obvious how to help these residents, or which residents may be more likely to encounter difficulty, and who may have trouble completing residency training. This study attempts to answer these questions and has shown some common characteristics to residents who require remediation or additional training. It reflects the strategies that were used at McMaster University in order to help such residents. This study also indicates how many residents were able to complete their residency training programs and it provides linkages to previous research and proposes new directions for future research in resident remediation.


title: Characterization of Catalyst Materials for PEMFCs using Analytical Electron Microscopy

contributor:
Botton, Gianluigi
Materials Science and Engineering

subject: Fuel Cell, Analytical Electron Microscopy

abstract:
The goal of current research is probing the relationship between catalyst features and
the fuel cell performance with a range of in-depth structural analysis. The study
investigated different catalyst systems including core-shell structured catalyst, catalysts
with unique carbon-transition metal oxide supports.
PtRu catalysts nanoparticles with unique core-shell structure, one of the most
practical catalysts in PEMFC technology, have been successfully obtained with the
evidence from the characterization results. It is found that the enhanced CO oxidation
may be achieved through the interactions between the Pt shell and Ru core atoms, which
can modify the electronic structure of the Pt surface by the presence of subsurface Ru
atoms or by disrupting the Pt surface arrangement. Furthermore, the possibility of
presence of the compressive strain within the Pt rich shell is proved by the lattice
measurements, which could significantly affect the catalytic activity.
Pt catalysts supported on complex oxide and carbon support were studied to
investigate the relationship between the catalyst and its support. Observations from
STEM images and HAADF and energy dispersive X-ray spectrometry demonstrate the
preferential distribution of Pt nanoparticles on the hybrid supports, which include Nb2O3
/ C, Ta2O5 / C, (Nb2O3+TiOx) / C, (Ta2O5+TiOx) / C, and (WO3+TiOx)/C). Such
evidence indicates the interaction between the catalyst and support is based on the
presence of an interconnected oxide network over the carbon support and the presence of
Pt strongly connected to the oxide network. In addition, using electron energy loss
spectroscopy (EELS), the electronic structure of the catalyst support under various
conditions was also studied to provide further evidence of the strong metal support
interaction effect.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: The Influence of Area 5 on the Excitation of Primary Motor Cortex

contributor:
Nelson, Aimee
Kinesiology

subject:
neurophysiology
transcranial magnetic stimulation
Brodmann's area 5
brain stimulation
cerebral cortex

abstract: Using functional magnetic resonance imaging in humans, Brodmann's area 5 (BA5) is observed to be activated during the suppression of motor output in the context of a NO-GO task. In monkeys, BA5 is associated with somatosensation and specifically linked with motor preparation. The goal of this thesis is to investigate BA5 influences on corticospinal excitability prior to the onset of movement, in the context of a GO/NO-GO paradigm. To achieve this goal, paired-pulse TMS is used to probe the functional connectivity between BA5 and ipsilateral primary motor cortex (M1) for a muscle specific to the hand. Three experiments are performed that investigate the differences in corticospinal output to the hand in a GO task versus a NO-GO task and the stimulation parameters that reveal such differences. Results indicate that BA5 is able to condition M1 prior to movement in a task-specific manner. Further, motor evoked potentials (MEPs) are suppressed in the context of a NO-GO task relative to a GO task, and task-specific differences rely on the intensity and direction of induced current in the cortex. In conclusion, data from this thesis contribute to our understanding of the role of BA5 in motor control.

abstract: Thesis

abstract: Master of Science in Kinesiology


title: For the Sake of the Whole: a Theological Examination of Dostoevsky's Elder Zosima Via Sergius Bulgakov

title: Zosima Through Bulgakov

contributor:
Kroeker, Travis
Religious Studies

abstract: The goal of this project is to organize and clarify the various theological ideas broached by Zosima, the enigmatic Elder of Dostoevsky’s Brothers Karamazov. I argue that the dogmatic theology of Sergius Bulgakov proves to be especially helpful in this regard. By examining the teachings, sayings and actions of Zosima in the light of Bulgakov’s major theological trilogy, On the Divine-Humanity, I aim to demonstrate conceptual resonance between the two. Through the lens of Bulgakov’s dogmatic theology, we can, I argue, better assess the cosmological, anthropological and ecclesiological themes that arise sporadically in the Elder’s dialogue throughout the text. By connecting Bulgakov with the character of Zosima, I hope not only to anchor Zosima theologically, but also to reveal the dramatic contours of Bulgakov’s theological project. The paradigm that emerges from a cross-examination of Zosima and Bulgakov is, I claim, a holistic theology centered on the dynamic interpenetration of God, man and the cosmos. I conclude that the concept of a divine milieu binding all things together in mystical communion, Bulgakov’s “Sophia,” serves to effectively consolidate Zosima’s diverse theological ideas.

abstract: Thesis

abstract: Master of Arts in Religion (MAR)


title: Relationships among body composition, physical activity, global self-worth and developmental coordination disorder in children over time

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
Developmental Coordination Disorder
Obesity
BMI
Waist Circumference
Global Self-worth
Children
Mixed-effects Modeling
Longitudinal Study
Percent Body Fat

abstract: It is well established in the literature that children with developmental coordination disorder (DCD) are more likely to be physically inactive, have unhealthy weight, and report lower perceptions of self-worth than typically developing (TD) children. Physical inactivity, overweight/obesity and low self-worth are important risk factors for many physical and psychological health conditions. The interrelationships among these factors, however, have yet to be explored in children with DCD. There is limited information on change in body composition measures and self-worth over time in children with DCD, the effect of physical activity (PA) on body composition, and whether the combined negative influence of having both DCD and obesity result in poorer conceptions of self-worth. In this dissertation, I present a series of studies that explore the connections among these factors using longitudinal, population-based data on a large cohort of children with and without poor motor coordination. The first study, presented in Chapter 2, describes the results of change in BMI and waist circumference (WC) in children with probable DCD (pDCD) and TD children over a five-year time period, and the effects of sex and PA on this relationship. Chapter 3 describes the results of the relationship between body fat, pDCD, and PA after addressing the measurement- related limitations of the study reported in Chapter 2. Chapter 4 describes the results of self-worth in children with pDCD and overweight/obesity, only pDCD, only overweight/obesity, and the control group at baseline as well as change over time. Collectively, the results show that children with pDCD have a consistently higher BMI, WC, and body fat than TD children. BMI and WC increases over time in children with pDCD; specifically boys with pDCD show a much accelerated increase in these measures. Scores of body composition measures increase with decrease in self-reported and objectively measured PA, but participation in PA does not explain why children with pDCD are more likely to have excess weight gain. Finally, children with both pDCD and overweight/obesity and children with either of these conditions alone report lower self- worth than the control group, and the change in self-worth between groups remains constant over time.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: Simulation Based Study of Solidification in Aluminum-Silicon System

contributor:
Hoyt, J. Jeffrey
Materials Science and Engineering

subject:
Molecular Dynamics
Solidification

abstract:
Using molecular dynamics (MD) and boundary element method (BEM), different aspects of solidification in the aluminum silicon system are studied. The angular embedding atom model (AEAM) was implemented on LAMMPS, and the necessary potentials are developed. Firstly, a modified version of the Stillinger-Weber (SW) interatomic potential for pure Si is proposed. The advantage of this potential is that, in contrast to the original SW form, the modified version allows one to grow diamond cubic crystal structures from the melt at high temperatures. Additionally, an Al-Si binary potential of the AEAM type is able to accurately predict the experimental enthalpy of mixing. It is also able to predict an Al-Si phase diagram with a eutectic concentration for the liquid that agrees with experiment within 4 at% and a eutectic temperature that differs from experiment by only 13 K.
Considering the importance of step mobility and step free energy on the solidification growth rate, chapters 3 and 4 are devoted to calculation of these concepts using MD simulations. In chapter 3 the step mobility, which is the proportionality constant between the velocity and driving force, was determined for the alloy with melt composition of Al-90%Si as a function of temperature and composition. It was found that mobility decreases fairly rapidly with the addition of Al solute. Also, from the variation with temperature, it appears the mobility is proportional to the interdiffusion coefficient in the liquid. It is observed that for the Al-60%Si alloy diffusion-controlled growth is the dominant scenario, even for a few degrees of undercooling. In chapter 4 equilibrium molecular dynamics (MD) simulations and the capillaryfluctuations method (CFM) are employed to calculate crystal-melt step free energies
at three different melt compositions. Anisotropy of steps are investigated by setting up the systems with different crystal orientations of steps on the high-symmetry interface plane, (111) in this case. A complete isotropy of step free energy is observed for Al-60%Si and Al-90%Si alloying systems, while CFM failed in determining step free energy in Al-30%Si due to lack of step roughness. In chapter 5 the BEM is utilized to numerically compute the concentration profile in a fluid phase in contact with an infinite array of equally spaced surface steps. In
addition, under the assumption that step motion is controlled by diffusion through the fluid phase, the growth rate is computed and the effect of step spacing, supersaturation
and boundary layer width is studied. BEM calculations were also used to study the phenomenon of step bunching during crystal growth and it is found that, in the absence of elastic strain energy, a sufficiently large perturbation in the position of a step from its regular spacing will lead to a step bunching instability.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: INVESTIGATION OF THE FEASIBILTY OF USING CHIRP-EVOKED ABR IN ESTIMATION OF LOUDNESS GROWTH

contributor:
Trainor, Laurel J.
Psychology

subject: Objective Loudness-Growth function

abstract: Loudness growth evaluation is important to comprehend the theoretical implication of loudness in both normal hearing and hearing impaired people, as well as applied applications in hearing-aid design. However, current psychoacoustic procedures are subjective, time consuming and require the constant attention of participants. The primary aim of the present study is to investigate the feasibility of objectively assessing the loudness growth function by using the Auditory Brainstem Response (ABR). Previous studies applied either non-frequency specific click stimuli or tone burst stimuli to evoke auditory brainstem responses. Although the advantage of a chirp stimulus in producing a more reliable response has been well documented in many studies, no one has previously used this stimulus to evaluate loudness growth functions. One octave-band chirp stimuli with center frequencies of 1000 Hz and 4000 Hz were chosen to evoke ABRs at 7 different stimulus intensities from 20 dB nHL to 80 dB nHL with 10 dB steps. In the psychoacoustic procedure, subjects were asked to rate the perceived loudness of each presented stimulus. The recorded ABR trials were averaged by a modified version of weighted averaging based on Bayesian inference. This method of averaging decreases the effects of non-stationary noise sources by calculating a number of locally-stationary noise sources based on a series of F-tests. The peak-to-trough amplitude of the most salient peak of the ABR at each intensity constituted the physiological loudness estimate. Linear and power functions relating the psychoacoustical results and the ABR measurements were compared. The obtained results were in good agreement with equal-loudness contours and estimated loudness from the loudness model for time-varying sounds of Glasberg, & Moore (2002).   We concluded that loudness growth can be estimated with ABRs to frequency-specific chirp stimuli.

abstract: Thesis

abstract: Master of Science (MSc)


title: Supporting New Practitioners in Child Welfare: Managers' Views

contributor:
Dumbrill, Gary
Sammon, Sheila
Social Work

subject:
Child Welfare
practitioners

abstract:
Child protection workers, who are often graduates of schools of social work, are the frontline professionals who are charged with making determinations about the safety of children, and developing interventions to address these safety concerns. Determining the safety of children is an extremely difficult process due to the complexity of the issues that may exist in any one situation, including the impact of social problems, the complexity of human behaviour, and the need to predict future actions and consequences.  On top of these challenges, child protection workers are subject to strict reporting and practice requirements imposed by the government and are required to provide a service mandated by legislation and funded by taxpayers. Given such responsibilities and constraints how does a person get prepared to work in the field of child welfare?
The purpose of this research was to explore what child welfare managers think prepares new BSW graduates to enter into the field of child welfare. In particular, how well are BSW graduates currently prepared? Is there a need to improve preparedness, and if so, what could be done to achieve this? Literature provided key but contradictory   perspectives in the debate around the preparedness of new workers. However, it is recognized that a partnership between education and child welfare could have beneficial effect on preparedness.
 Using the approaches of Interpretive Social Science and Critical Social Science, this qualitative research study was designed using semi-structured interviews to generate the data.  Data was interpreted and analyzed through the techniques of coding and memo-writing from Grounded Theory.  A colleague conducted a separate study of new workers which provided an opportunity to compare and contrast managers perspectives with those of new workers leading to a clearer understanding of preparedness.
    Overall, new workers are deemed to be prepared in terms of having the knowledge base that is needed to start working in child welfare. However, child welfare managers believe more learning opportunities need to be built into school programs that focus on applying theory to practice, child welfare specific knowledge, and understanding the complexity of mandated work. Field placements in child welfare settings, are considered to be valuable in preparing students prior to employment. Child welfare managers believe that an alliance between education and the field could optimize the readiness of new workers so as to ensure quality service for families in our community.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Using geo-spatial analysis for effective community paramedicine

contributor:
Yiannakoulias, Niko
Geography

subject:
Community Paramedicine
Frequent Users
Spatial Analysis
Paramedic

abstract:
Paramedic services are developing a new model of service delivery known as community paramedicine (CP). This service delivery model seeks to build on existing paramedic skills, establish collaboration with non-traditional health care partners, and create alternative pathways for accessing care. Frequent users of paramedic services represent patients that are of particular interest to CP programs. Chapters 2 and 3 of this thesis address questions of effective delivery of these programs.
 The second chapter is a spatial-temporal analysis of frequent users in Hamilton, ON. Drawing on concepts of time-geography and dynamic ambulance deployment, this analysis identifies space-time patterns in paramedic service utilization by frequent users. Data were aggregated to represent daily demand in terms of space and time. Analysis employed generalized linear mixed models that included a random slope effect for time intervals for each geographic unit. Fixed effects included distance to emergency department, proportion of residential addresses, and proportion of older adult population. Locations and times that had greater or less than expected daily demand from frequent users were identified. The findings can be used to tailor deployment of community paramedics in dual-capacity roles to address the system demand of frequent users.
 The third chapter analyzes the geographic influence of CP service delivery in Renfrew County, ON. This research draws on concepts of spatial accessibility and geographic profiling to estimate spatially defined probabilities of paramedic service use by frequent users. Due to ongoing CP programs within the county, the resultant community health profiles serve as an evaluation of the benefit of these programs. The community health profiles can also be used to assess community level probabilities of patient needs for future interventions. This analysis can serve as a new way to assess spatial accessibility to health care services and identify locations with increased risk of frequent use of paramedic services.

abstract: Thesis

abstract: Master of Arts (MA)


title: HYDRAULIC SPRAYER CONTROL FOR THE COOLING AND QUENCHING OF MAGNESIUM AND ALUMINIUM ALLOYS

contributor:
Bone, Gary M.
Shankar, Sumanth
Mechanical Engineering

subject: Hydraulic, Controls, High Speed, High Flowrate, Sprayer, Water Hydrualics, Magnesium Casting, Light metal Casting, Control of Casting

abstract:
For over 30 years research has been done concerning the solidification and quenching of light metal alloys for the purpose of improving material properties.  This thesis is concerned with an interesting new process for casting metals, by spraying water onto a sand mould, removing the sand and the directly quenching the part.  This process is challenging since the component during solidification is extremely fragile, and the rate of cooling that is needed could seriously damage it.  The water flow rate to the component needs to be quickly and precisely controlled. Additionally as this a new method there is very little prior art.
The purpose of this thesis to develop a control system for the water sprayers flow rates. With this system the flow rate through the nozzles will be controlled indirectly using pressure feedback. The material properties and casting process, and how they influenced the design and construction of the spraying apparatus, are explained first.  The hydraulic plant being controlled consists of three proportional valves connected to six spray nozzles. Based on experiments, the plant is extremely nonlinear making it difficult to control.
Several controllers were developed and compared experimentally. The best performance was produced by extending a proportional plus integral plus derivative controller by adding an empirical nonlinear feedforward component; smoothing the setpoint; bounding the integration term; adding one bias at time zero and a 2nd bias for the remaining time (to mitigate valve stiction and to prime the hoses).  This extended PID controller produced a 0.7% mean error and 1.9% mean absolute error for a multi-step setpoint covering a range of 0 to 80 PSI.  Its performance was also highly repeatable. The standard deviations of the mean error, mean absolute error and maximum absolute error were less than 0.2 PSI over five runs.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: During the sand casting of aluminium and magnesium rapid cooling will greatly improve the material properties.  By containing the liquid metal in a water soluble sand mould, and spraying it with water; the desired part shape and rapid cooling can be achieved.  Removing the mould requires a powerful high flow rate jet. During the solidification of the metal, the flow rate must be reduced or the part would be demolished.  This necessitated the development of a high speed, high flow rate controller to adjust the flow rate to remove the sand but not damage the part, and to maintain a smooth continuous cooling rate.  The hydraulic system being controlled consists of three electronic valves connected to six spray nozzles. Several controllers are developed and compared experimentally. The best controller is shown to provide a quick and precise response.


title: The Measurement of Recovery Time in Patients Receiving Hemodialysis for End-Stage Renal Disease

contributor:
Walsh, Michael
Health Research Methodology

subject:
Nephrology
Quality of life
Dialysis
Measurement

abstract: Hemodialysis induces various symptoms in many patients.  However, the type of dialysis symptoms induced and how they contribute to recovery time remains unclear. This study aims to understand patient experiences reporting dialysis recovery time and associated symptoms using three separate novel instruments developed for this study. We conducted a 13-week prospective cohort study in prevalent in-center hemodialysis patients and measured their recovery time using three instruments. Instrument A inquired how long it took to recover from the last dialysis treatment. Instrument B inquired recovery time from last treatment for each of 10 specified symptoms and Instrument C included symptom severity to Instrument B. Each instrument was used for each dialysis treatment for one week. We compared patient response and distribution of recovery time found with each instrument using mixed-effects logistic regression models. 118 participants were recruited from two centres of which 914 (86%) of 1062 expected responses were completed. Recovery time using instrument A resulted in more participants identifying some recovery time from dialysis (83 to 86%) as compared with Instrument B (66 to 80%, p = 0.001) and Instrument C (69 to 73%, p <0.001). The third visit of the week was associated with fewer patients reporting recovery time (p = 0.036). However, Instrument B (p = 0.016) and Instrument C (p < 0.001) showed a longer recovery time compared to the distribution of recovery time of Instrument A. Lack of energy was the most common symptom following dialysis (69 to 77% of all patients). Recovery time with Instrument A was a significant predictor of kidney-specific component scores and mental component score as measured by the Kidney Disease Quality of Life-36 instrument. Recovery time is complex, and includes different symptoms that vary in duration. Attempts to reduce recovery time may impact specific symptoms differentially.

abstract: Thesis

abstract: Master of Science (MSc)


title: Numerical Investigation of Tuned Liquid Damper Performance Attached to a Single Degree of Freedom Structure

contributor:
Hamed, Mohamed
Mechanical Engineering

abstract:
Tuned liquid dampers (TLDs) are increasingly being used as dynamic vibration absorbers to minimize the vibration of structures. A tuned liquid damper is a tank filled with a liquid. When attached to a structure, the liquid sloshing action inside the TLD dampens and absorbs part of the energy given to the structure. The difficulty in designing TLDs arises from its nonlinear response (behavior), which requires a detailed understanding of the sloshing motion inside the TLD. An in-house numerical algorithm has been developed to investigate and understand liquid sloshing motion inside TLDs and to evaluate the TLD damping performance when coupled with a vibrating Single Degree of Freedom (SDOF) structure. The model is based on the finite-difference method. The Volume of Fluid method has been used to reconstruct the liquid free surface. The Continuum Surface Force model has been used to model and resolve the discontinuity accompanied with wave breaking that might take place at the liquid surface. All dynamic stresses on the free surface have been taken into consideration to evaluate wave breaking. No linearization assumptions have been used in solving the Navier-Stokes equations. The developed numerical model incorporates the interaction between the structure dynamics and the TLD. In this study, the structure has been assumed as a SDOF system and its dynamic response has been calculated using the Duhamel integral method.
The model has been validated against experimental data with and without the structure. Good agreement was obtained between the numerical and the experimental results. An extensive parametric study has been carried out using the developed numerical model to investigate the effect of TLD-structure frequency ratio (fTLD/fs), external excitation amplitude-TLD length ratio (A/L) and external excitation frequency ratio (fTLD/fe) on the TLD damping performance. A new parameter defined as the Energy Dissipation Factor (EDF) has been introduced to quantify the TLD damping performance. The present results have been used to develop a useful design empirical correlation of the damping effect of the TLD as function of fTLD/fs, A/L and fTLD/fe. .

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: A Computational Analysis of the Structure of the Genetic Code

contributor:
Stone, Jonathon
Biology

subject:
genetic code
evolution
optimality
coevolution
column theory
stop codons
origin of the genetic code
structure of the genetic code
monte carlo simulations

abstract:
The standard genetic code (SGC) is the cipher used by nearly all organisms to transcribe information stored in DNA and translate it into its amino acid counterparts. Since the early 1960s, researchers have observed that the SGC is structured so that similar codons encode amino acids with similar physiochemical properties. This structure has been hypothesized to buffer the SGC against transcription or translational error because single nucleotide mutations usually either are silent or impart minimal effect on the containing protein.  We herein briefly review different theories for the origin of that structure. We also briefly review different computational experiments designed to quantify buffering capacity for the SGC.
We report on computational Monte Carlo simulations that we performed using a computer program that we developed, AGCT. In the simulations, the SGC was ranked against other, hypothetical genetic codes (HGC) for its ability to minimize physiochemical distances between amino acids encoded by codons separated by single nucleotide mutations.  We analyzed unappreciated structural aspects and neglected properties in the SGC. We found that error measure type affected SGC ranking. We also found that altering stop codon positions had no effect on SGC ranking, but including stop codons in error calculations improved SGC ranking. We analyzed 49 properties individually and identified conserved properties. Among these, we found that long-range non-bonded energy is more conserved than is  polar requirement, which previously was considered to be the most conserved property in the SGC. We also analyzed properties in combinations. We hypothesized that the SGC is organized as a compromise among multiple properties.
Finally, we used AGCT to test whether different theories on the origin of the SGC could explain more convincingly the buffering capacity in the SGC. We found that, without accounting for transition/transversion biases, the SGC ranking was modest enough under constraints imposed by the coevolution and four column theories that it could be explained due to constraints associated with either theory (or both theories); however, when transition/transversion biases were included, only the four column theory returned a SGC ranking modest enough that it could be explained due to constraints associated with that theory.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The standard genetic code (SGC) is the cipher used almost universally to transcribe information stored in DNA and translate it to amino acid counterparts. Since the mid 1960s, researchers have recognized that the SGC is organized so that similar three-nucleotide RNA codons encode amino acids with similar properties; researchers consequently hypothesized that the SGC is structured to minimize effects from transcription or translation errors. This hypothesis has been tested using computer simulation. I briefly review results from those studies, complement them by analyzing unappreciated structural aspects and neglected properties, and test two theories on the origin of the SGC.


title: Unequally Placed: A Case Study of the Geographical Organization of Social Services for Marginalized Youth

contributor:
Heath, Melanie
Sociology

subject:
geography
organizations
youth
marginalization
Ontario
social services

abstract:
Jackson, 16, has just lost his father to cancer and has nowhere to go so he drops out of high school to look for work. Chrissy, 18, and a recovering addict, sometimes wakes up still thinking about the drugs. She doesn’t use the drugs, but she says that she still needs them. Steph, 20, is on a path towards ‘normal expected success’ when past trauma re-enters her every day. She takes all her prescribed pills on multiple occasions to end her life because her family doesn’t believe the abuse she describes. She tells me she can’t think about the future because she still has to be alive to deal with it. And Mark, 22, has been homeless for 5 years, not consecutively, but long enough to equate home with the streets more than with the times he’s had a roof over his head. These are some of the everyday lives of young people included in this dissertation.
Using the case of one organization that operates across a rural and urban context in Ontario, Canada, I investigate the organization of social services for youth. Throughout I show that if young people experience forms of marginalization, and disadvantage like those described above in an urban context, they will likely know about and have access to local support centres, coordinated organizational processes, referral programs, and a network of social resources that are able to address their multiple and complex needs. The rural context, however, works in drastically different ways, even when the services are expected to be the same. In other words, the geographical location operates as a social force that shapes both young people’s experiences of, and organizational responses to, inequality. In the pages that follow I explore how intersecting social processes alleviate forms of disadvantage experienced by youth in urban settings, and paradoxically, reproduce and sustain forms of inequality experienced by rural youth. Importantly this research shows that the geographical location of people in disadvantaged positions matters to the ways that the experience unfolds. Getting out of marginalized positions for rural youth is more challenging because the rural setting is not set up to do this work; in other words, compared to urban settings, the rural context is unequally placed.

abstract: Dissertation

abstract: Candidate in Philosophy


title: Henry Fielding's Whores

contributor:
Walmsley, Peter
English and Cultural Studies

subject:
Henry Fielding
Prostitution
Eighteenth Century
London
Britain

abstract: The mercenary whore is a recurring character-type in Henry Fielding’s plays and early fictions. This thesis examines Fielding’s representations of the sex-worker in relation to popular eighteenth-century discourses surrounding prostitution reform and the so-called ‘woman question’. Fielding routinely confronted, and at times affronted his audience’s sensibilities toward sexuality, and London’s infamous sex-trade was a particularly contentious issue among the moralists, politicians, and religious zealots of his day. As a writer of stage comedy and satirical fiction, Fielding attempted to laugh his audience into a reformed sensibility toward whoredom. He complicates common perceptions of the whore as a diseased, licentious, and irredeemable social other by exposing the folly, fallibility, and ultimate humanity of the modern sex-worker. By investigating three of Fielding’s stage comedies—"The Covent-Garden Tragedy" (1732), "The Modern Husband" (1734), and "Miss Lucy in Town" (1742)—and two of his early prose satires—"Shamela" (1741) and "Joseph Andrews" (1742)—in relation to broader sociocultural concerns and anxieties surrounding prostitution in eighteenth-century Britain, this thesis locates Fielding’s early humanitarian efforts to engender a reformed paradigm of charitable sympathy for fallen women later championed in his work as a justice and magistrate.

abstract: Thesis

abstract: Master of Arts (MA)


title: MODEL-BASED DEFORMABLE REGISTRATION OF MRI BREAST IMAGES WITH ENHANCED FEATURE SELECTION

contributor:
Sirouspour, Shahin
Biomedical Engineering

subject:
Image Registration
Deformable Model
Feature Extraction
Finite Element Model

abstract:
This thesis is concerned with model-based non-rigid registration of single-modality magnetic resonance images of compressed and uncompressed breast tissue in breast cancer diagnostic/interventional imaging.
First, a volumetric registration algorithm is developed which solves the registration as a state estimation problem. Using a static deformation model. To reduce computations, the similarity measure is calculated at some specific points called control points. These control points can be from a low resolution image grid or any irregular image grid.
 Our numerical analysis has shown that control points placed in the area without much information; i.e with small or no changes in image intensity, yield negligible deformation. Therefore, the selection of the control points can significantly impact the accuracy and computation complexity of the registration algorithms. An extension of the speeded up robust features (SURF) to 3D is proposed for enhanced selection of the control points in deformable image registration. The impact of this new control point selection method on the performance of the registration algorithm is analyzed by comparing it to the case where regular grid control points are used. The results show that the number of control points could be reduced by a factor of ten with new selection methodology without sacrificing performance.
Second image registration method is proposed in which, based on a segmented pre-operative image, a deformation model of the breast tissue is developed and discretized in the spatial domain using the method of finite elements. The compression of the preoperative image is modeled by applying smooth forces on the surface of the breast where compression plates are placed. Image registration is accomplished by formulating and solving an optimization problem. The cost function is a similarity measure between the deformed preoperative image and intra-operative image computed at some control point and the decision variables are the tissue interaction forces.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Living labeled: how students make meaning of their label of autism

contributor:
Sinding, Christina
Social Work

subject: Autism, Labeling, Accommodation, Expectation, Value/Undervalue, High school students, critical disability studies

abstract:
The purpose of this study is to examine how high school students labeled with autism make meaning of their label and how, for them, the label functions in their day-to-day lives. Being diagnosed with autism can have many implications for an individual and his or her family and how a label is understood is very much connected to the impact that it has.  A label can be instrumental in accessing resources and supports that enable a person to thrive, but it can also conjure stereotypes which may categorize a person or limit them in particular ways.
	Using critical theory and phenomenological analysis, short semi-structured interviews were conducted with high school aged participants prior to their attending a full day workshop.  The workshop included half-day art creation and a half-day focus group which sought to understand participants’ experiences through their descriptions of their art and through collaborative discussion about their experience living labeled.
	The findings suggest that while their experiences are as diverse as the individuals who have them, there are similarities in how the label functions which may be more universal. Participants in this study discussed how the label of autism assigns positive or (more often) negative value to a person; how their label linked them with certain resources (and not others), and how they experienced and understood these resources;  and the way labels can both protect and confine a person.  Consideration of how high school students understand of their label of autism can prompt us all to think more critically about how labels, and the meanings we assign to them, affect and shape experience for those who live labeled.

abstract: Thesis

abstract: Master of Social Work (MSW)


title: Multicopy gene family evolution on primate Y chromosomes

contributor:
Evans, Ben
Biology

subject: Y chromosome, gene copy number evolution, Old World Primates, genome structure

abstract:
Unlike the autosomes, the Y chromosome in humans and other primates has few protein coding genes, with only a few dozen single-copy genes and several tandem duplicated gene families, called the "ampliconic" genes. The interaction of many biological and evolutionary factors is responsible for this structural heterogeneity among different parts of the genome.
We sequenced and assayed the copy numbers of Y-linked, single-copy genes and ampliconic genes in a group of closely related macaque monkeys, then fit models of gene family evolution to this data along with whole genome data from human, chimpanzee, and rhesus macaque. Our results (i) recovered evidence for several novel examples of gene conversion in papionin monkeys, (ii) indicate that ampliconic gene families evolve faster than autosomal gene families and than single-copy genes on the Y chromosome, and that (iii) Y-linked singleton and autosomal gene families evolved faster in great apes than they do in other Old World higher Primates.
These findings highlight the evolutionary eccentricity of duplicated genes on the Y chromosome and suggest an important role for natural selection and gene conversion in the evolution of Y-linked gene duplicates.

abstract: Thesis

abstract: Master of Science (MSc)


title: Impacts of the Interim Federal Health Program on healthcare access and provision for refugees and refugee claimants in Canada: A stakeholder analysis

contributor:
Baumann, Andrea
Global Health

subject:
refugee health policy
IFHP
healthcare access
stakeholder analysis

abstract:
Background: Refugees and refugee claimants experience health needs upon arrival in Canada. Retrenchments to the Interim Federal Health program (IFHP) in 2012 greatly reduced healthcare access for refugee claimants, generating concerns among healthcare providers and other stakeholders affected by the reforms. In 2014 a new IFH program temporarily reinstated access to some health services however, little is known about the reforms and more information is needed to map its impact on key stakeholders. This study aims to examine the perception of key stakeholders regarding the impact of the 2014 reforms on the policy’s intermediary goals: access and provision of healthcare.

Methodology: Data was collected using semi-structured key informant interviews with refugee health policy stakeholders (n=23), refugees and refugee claimants (n=6), policy makers and government officials (n=5), civil society organizations (n=6) and professionals and practitioners (n=6). Data was analysed using a constant comparative approach with NVivo 10 (QSR International). A stakeholder analysis was used to map out key stakeholder perceptions, interests and influences in refugee health policy and a content analysis was further employed to abstract themes associated with barriers and facilitators to access and provision of healthcare in the current situation.

Results: The findings provide information for management of stakeholder engagement revealing the perceptions of key stakeholders on the 2014 reforms: eight were opposed to the reforms, eight held mixed positions, four supported the reforms and one did not comment. Five facilitators to accessing healthcare were identified. Eighteen themes emerged under four health care access and provision barrier categories: cognitive, socio-political, structural and financial. There were four common themes perceived among all stakeholder groups: lack of communication and awareness of refugee and provider, lack of care provider training leading to unfamiliarity with IFHP, lack of continuity and comprehensive care and the political discourse leading to refugee and claimant social exclusion. Other common barrier themes included healthcare affordability for refugees and the healthcare system, fear of the healthcare system, and interaction with the Ontario Temporary Health Program.

Conclusion: The study highlights that reforms to the IFHP in 2014 have transferred refugee health responsibility to provincial authorities and healthcare institutions resulting in bureaucratic strains, inefficiencies, overburdened administration and increased health outcome disparities as refugees and claimants choose to delay seeking healthcare due to existing barriers.  There are some benefits to the reforms, but the lack of support and mixed opinions among the majority of stakeholders emphasize the need for reformulation of policy with stakeholder engagement. This study recommends future refugee health reform strategies incorporate stakeholder leadership, cooperation and perspectives, as revealed in this research, to successfully move healthcare policy from theory to practice.

abstract: Thesis

abstract: Master of Science (MSc)


title: Functional analysis of candidate phosphorylation sites of telomere repeat binding factor 2 (TRF2)

contributor:
Zhu, Xu-Dong
Biology

subject: TRF2, cancer, telomeres

abstract: TRF2 is a multifunctional protein implicated in telomere length maintenance, DNA double strand break repair and telomere protection. TRF2 undergoes extensive post-translational modification including phosphorylation. Mass spectrometry analysis has identified two candidate TRF2 phosphorylation sites: T317 and S323. In this study, the roles of these two potential phosphorylation sites were examined for their role in cell growth, telomere length maintenance and DNA damage response. Through retroviral infection, HT1080, HeLaII and GM847 cell lines stably expressing the vector alone, Myc-tagged wild type TRF2, Myc-tagged TRF2 carrying a nonphosphorylatable mutation of either T317A or S323A and Myc-tagged TRF2 carrying a phosphomimic mutation of either T317D or S323D were generated. Overexpression of TRF2 mutant alleles has no effect on cell growth and proliferation as well as TRF2 association with ALT-associated PML bodies. On the other hand, the effect of TRF2 mutant alleles on DNA damage response and telomere length maintenance is inconclusive and requires further investigation.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: TRF2 is a multifunctional protein implicated in telomere length maintenance, DNA damage repair and telomere protection. TRF2 undergoes extensive post-translational modification, which in turn regulates its DNA binding activity, protein stability and cellular localization. TRF2 is found to be phosphorylated at a number of serine/threonine sites, including T317 and S323. In this study, the candidate phosphorylation sites T317 and S323 of TRF2 were analyzed for their potential roles in cell growth, telomere length maintenance and DNA damage response.


title: Some Aspects of Costing and Contouring Programs for Point-To-Point Numerically Controlled Machine Tools

contributor:
de Malherbe, M. C.
Duncan, J. L.
Production

subject: costing, contouring, numerically, machine, tools, point-to-point, terminal, operations

abstract:
 This thesis is an investigation of some of the aspects of costing and machining that are applicable to numerically controlled (N/C) machine tools with particular reference to the facilities at McMaster University,and is divided into two sections.

 Section A is a brief discussion of the suitability of N/C for simulation methods and a review of the principles of metal cutting and the problems involved in estimating costs. A method is devised to simulate the machining of "typical" parts that have been generated by a random strategy. The results of the simulation were used to find a relationship between the geometric parameters of each part and the time required for all the machining operations to make that part, this relationship was called the "complexity factor" for the part. Sugestions for possible future extensions to the work were made.

 Section B is a feasibility study for increasing the range of use of a Moog point-to-point N/C machine to contouring, using the computer facilities available at McMaster University. It was proposed to produce a numerical control tape to machine a general oval based on a method of approximate linear interpolations using an on-line, time sharing computer terminal and a PDP "mini computer". The contouring method was tested by machining a circular groove (an oval with equal major and minor axes) and measuring the accuracy. The possibility of extending the work to other contours and three dimensional solids is discussed.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: TSALAGI KANOHEDA DUNIHNOHELVHI  (CHEROKEE STORIES THAT ARE SPOKEN OR TOLD): THE LIVING ORAL TRADITION OF THE EASTERN CHEROKEE  AND ITS CULTURAL CONTINUANCE

contributor:
Coleman, Daniel
English and Cultural Studies

subject:
Oral Tradition
Eastern Cherokee

abstract:
The power and beauty of all Indigenous cultures lies within the oral tradition of each respective group.  The Eastern Cherokees continue today to regenerate and reinvigorate their culture, lifeways, spirituality, dance and song, and healing practices through their daily use of oral storytelling and historical narratives.  As a small Native community in the southern United States (North Carolina), the Eastern Band of Cherokee Indians (EBCI) function as a sovereign Indigenous nation who have steadfastly remained in their original homeland, despite a forced removal of most of the tribe in the late 1830s, infamously known as the Trail of Tears.  These are the descendants of those brave Giduwah ancestors who resisted the colonizer demands to remove to Indian Territory, now called Oklahoma.  The oral tradition with its ancient cultural teachings and stories provide the impetus for the Eastern Band to reassert their indigeneity to their sacred homeland in the Smoky Mountains, and to practice their unique and distinctive culture so that future generations of their young will keep the language and the old ways alive.
Oral storytellers and community Elders use their spoken word art and share their vast orature in order to both revitalize the culture within their Native community, and to share cultural knowledge and educate those thousands of non-Cherokee tourists who visit there.  My research into the living oral tradition of the Eastern Cherokees involved recording and collecting the oral stories shared at community events, and creating an archive in order to examine these varied stories and cultural specifics.  Although it is difficult to analyze orality transcribed onto a written page, it was necessary for this formal dissertation.  I have used a Native and specifically Cherokee theoretical methodology, known as Duyvkta and Gadugi, in order to frame and explicate the wealth of cultural knowledge held within this oral tradition.  This dissertation may be complete, but the stories and spoken words will live on for the Eastern Cherokee, and there is much more work to be done so that the sacred Fire will continue to burn.  Hvwa.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Normally a formal dissertation in English Literature would examine works of literature and apply western literary theory to examine the intricacies of the poem or story.  My project attempts a more difficult task – that of taking the spoken word in the form of Cherokee oral stories and, first, transcribing this orature into written words on paper, and, second, using an Indigenous critical approach in order to present a Cherokee-centric method of understanding the rich cultural and spiritual teachings held within these spoken stories and histories.  I offer the ancient concepts of Gadugi (giving of oneself and working for the betterment of the community) and Duyvkta (walking the right path of harmony and balance) as ways of learning from the ancient and contemporary stories of the Eastern Cherokee.  It is the originary oral tradition which created the basic foundation of Cherokee culture and life, and I humbly wish to offer my research to the growing field of study of Native orature of Turtle Island.  Sgi.


title: ‘IT’S JUST A THING I DO’:  YOUNG KITCHEN WORKERS’ COMMUNITIES OF PRACTICE AND CAREERS OF PRECARITY

contributor:
Donna, Baines
Labour Studies

subject:
restaurant workers
precarity
young workers
cook
chef
community of practice
employment strain
culinary industry

abstract: The culinary industry is well known for its unforgiving workplace conditions and precarious employment relationships. Low pay, unpredictable schedules, and workplace harassment are commonplace. However, workers in the industry are often dedicated to their craft and passionate about the industry in which they work. This thesis aims to come to a better understanding of the working lives of young kitchen workers in Toronto. Using a narrative approach to research, this thesis draws on the experiences of nine young kitchen workers. Their narratives are analyzed through examining their participation in communities of practice and their experiences of employment strain. It seeks to answer the question of why these individuals enjoy their work but often hate their jobs.

abstract: Thesis

abstract: Master of Arts (MA)


title: Simulation of Mechanical Behaviour of Pure Titanium

type: Image Thesis

contributor:
Wu, Peidong
Mechanical Engineering

subject:
Plastic Deformation
Titanium
Crystal Plasticity Modelling
Visco-Plastic Self-Consistent
Mechanical Behaviour

abstract:
Titanium is a widely applied material in industries and characterized by highly anisotropic mechanical behaviour. To study the special property of titanium, many kinds of mechanical loading tests have been conducted. Moreover, researchers attempted to reproduce these experiments with numerical methods. This paper will present an overview about the deformation mechanisms and related representative studies of titanium.

Among the numerical methods, Taylor type and self-consistent crystal plasticity models are two of the most common ones seen in literature. Simulation of some mechanical loading tests using visco-plastic self-consistent model was carried out and compared with the results given by Taylor type model. It has been found that self-consistent model prevails in the reproduction of stress-strain response and texture evolution.

During the calculation of self-consistent model, there are totally 4 kinds of self-consistent schemes available for linearization process. The author investigated 4 groups of simulation works using different self-consistent schemes. But no evident distinction has been observed.

The application of visco-plastic self-consistent model in commercial purity titanium is studied at the end. The simulation results successfully captured the general features of 9 mechanical loading tests.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Optical Power Reduction for Multiple-Subcarrier Modulated Indoor Wireless Optical Channels

contributor:
Hranilovic, Steve
Electrical and Computer Engineering

subject: multiple-subcarrier, modulated, wireless, optical, bandwith-efficient, multi-access, channels, power

abstract:
 Multiple-subcarrier modulated (MSM) indoor wireless optical systems provide highspeed bandwidth-efficient communication as well as multi-access capability at low cost. A major drawback of such systems is the high average optical power requirement. To address this problem, trellis codes are designed for data transmission realizing an average optical power reduction as high as 0.95 dB. A simultaneous peak optical power reduction up to 0.44 dB is also possible by employing this technique.

 Moreover, the unregulated bandwidth available in wireless optical channels is exploited to reduce the average optical power in MSM wireless optical systems. Data transmission is confined in a bandwidth located near DC, while reserved carrier signals are designed outside the data bandwidth to reduce the average optical power. Distorted out-of-band signals at higher frequency are removed at the receiver by low-pass filtering and not used for detection. To design the out-of-band carrier amplitudes, both a standard optimization algorithm over the set of real numbers and an exhaustive search over discrete constellation are proposed. It is shown that significant average optical power reduction as high as 2.56 dB is achieved.

 It is assumed that a symbol-by-symbol bias is used in MSM wireless optical systems since it offers significant optical power reduction. The received DC bias level provides a degree of diversity and is used at the receiver to improve detection. It is also used to design trellis codes with better distance properties. In this manner, an additional average optical power reduction up to 0.50 dB is achieved with a simultaneous peak power reduction of 0.46 dB for MSM wireless optical systems.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: SCREENING PROTOCOLS FOR IDENTIFYING VICTIMS OF HUMAN TRAFFICKING IN AN ENGLISH-SPEAKING HEALTHCARE SETTING: A SCOPING REVIEW

contributor:
Carranza, Mirna
Global Health

subject:
human trafficking
healthcare
screening protocol
victim identification
policy development

abstract: Human trafficking is a global issue with every country being affected. Victims of human trafficking endure extreme and prolonged psychological, physical, and sexual trauma, which often lead to healthcare facility visits while in captivity. It is estimated that 28% of human trafficking victims come into contact with a healthcare professional, yet few victims are detected in the healthcare setting. The aims of this study were, therefore, to summarize and compare English screening protocol literature, disseminate the most effective screening questions in a format easily accessible to healthcare providers, and to identify gaps in the literature. Research about utilizing trafficking screening protocols in a healthcare setting is a relatively new phenomenon since trafficking has been traditionally framed as a security matter rather than a health matter. A scoping review was conducted using the five-stage Arksey and O’Malley (2005) framework with revisions from Daudt, van Mossel, and Scott (2013), and Levac, Colquhoun and O’Brien (2010). Findings were summarized thematically: 1) pre-screening, 2) screening questions, 3) post-screening, and 4) training. Twenty-nine sources were included of 325 identified with most (68.97%) being published in the United States. There was only one validated screening protocol: 94.12% of screening protocols lacked scientific reasoning for chosen questions. With limited access to evidence-based screening protocols, healthcare professionals globally may be using outdated screening questions that are less effective when trying to identify trafficking victims.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Victims of trafficking sustain psychological, physical, and sexual injuries, which often lead to healthcare facility visits. Although trafficking victims do come into contact with healthcare professionals while in captivity, few victims are identified in the healthcare setting. This study, therefore, aims to uncover English human trafficking screening protocols, to compare the protocols, and to share the most effective questions for healthcare professionals when trying to identify a victim of trafficking. Previous studies have failed to address this issue globally since trafficking has traditionally been framed as a security matter rather than a health matter. Electronic databases were searched using defined keywords for screening protocol literature, revealing 29 relevant documents after review. Only one, recently developed screening tool was validated, meaning that healthcare professionals globally may be using outdated screening questions that are less effective when trying to identifying trafficking victims.


title: Effects of fear on transmission dynamics of infectious diseases

contributor:
Earn, David J.D.
Mathematics

subject:
applied mathematics
epidemiology
mathematical modelling
mathematical biology

abstract:
An epidemiological model that incorporates individual adoption of
protective behaviours due to fear of contracting an infectious disease
is presented. These adaptive behaviours are assumed to lower an
individual's risk of infection. The dynamics of this model are
analyzed and the effects of fear on important public health metrics
such as outbreak length, final size, and peak prevalence are
investigated. It is concluded that the coupled dynamics of fear- and
disease-spread are rich and can lead to counter-intuitive effects on
the public health metrics considered. In particular, it is not always
the case that more effective protective behaviours lead to the most
favourable population-level outcomes; intermediate levels of
effectiveness are optimal in some cases. This result depends on when
fearful individuals become infected with respect to the main outbreak
that is mostly driven by the infection of fully susceptible
individuals.

abstract: Thesis

abstract: Master of Science (MSc)


title: Multi-stage Stochastic Capacity Expansion: Models and Algorithms

contributor:
Huang, Kai
Business

subject:
Capacity expansion
Multi-stage stochastic programming
Decomposition
Spot market capacity
Contract capacity

abstract: In this dissertation, we study several stochastic capacity expansion models in the presence of permanent, spot market, and contract capacity for acquisition. Using a scenario tree approach to handle the data uncertainty of the problems, we develop multi-stage stochastic integer programming formulations for these models. First, we study multi-period single resource stochastic capacity expansion problems, where different sources of capacity are available to the decision maker. We develop efficient algorithms that can solve these models to optimality in polynomial time. Second, we study multi-period stochastic network capacity expansion problems with different sources for capacity. The proposed models are NP-hard multi-stage stochastic integer programs and we develop an efficient, asymptotically convergent approximation algorithm to solve them. Third, we consider some decomposition algorithms to solve the proposed multi-stage stochastic network capacity expansion problem. We propose an enhanced Benders' decomposition algorithm to solve the problem, and a Benders' decomposition-based heuristic algorithm to find tight bounds for it. Finally, we extend the stochastic network capacity expansion model by imposing budget restriction on permanent capacity acquisition cost. We design a Lagrangian relaxation algorithm to solve the model, including heuristic methods to find tight upper bounds for it.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Determining the fitness consequences of kin recognition responses in allocation and morphological traits

contributor:
Dudley, Susan
Biology

subject:
kin recognition
fitness
consequences
natural selection
multilevel selection
root allocation
competition
kin selection
resource partitioning
Brassica oleracea

abstract: Many plant species recognize kin and respond with changes in functional traits. Researchers hypothesize that siblings compete less than strangers. However, no study has directly tested whether siblings are less competitive. Measuring natural selection on kin recognition responses in root allocation and other destructively measured traits is challenging, since trait and fitness cannot be measured on the same individual. Here, a methodology using family-level selection is developed, measuring the trait on one individual and measuring its fitness value using another related individual. Three greenhouse pot experiments were conducted using six Brassica oleracea cultivars at two nutrient levels. We investigated whether root allocation and morphological traits were under natural selection. We tested whether or not there was cultivar recognition or resource partitioning in B. oleracea. We found that putative competitive traits (size, height, emergence and root allocation) had expected patterns of individual selection for an increase in each trait and group selection for a reduction of each trait. There was no indication that resource partitioning was occurring or that B. oleracea could recognize cultivars. However, plants were experiencing competitive interactions within pots. In conclusion, we demonstrate that using family-level selection estimates the fitness consequences of root allocation and morphological traits.

abstract: Thesis

abstract: Master of Science (MSc)


title: Biological Motion Perception in Persons with Schizophrenia

contributor:
Christensen, Bruce
Sekuler, Allison
Psychology

subject: Schizophrenia, Biological Motion, Vision, Social Perception, Emotion Perception

abstract:
Schizophrenia (SCZ) is associated with robust social deficits, which have been shown to precede illness onset and predict functional outcome. As a result, social functioning is an important developmental domain affected by SCZ, which likely has a downstream negative impact on other functional abilities, such as interpersonal relationships and vocational capacity. Patients with SCZ also demonstrate significant visual perceptual deficits; however, a remaining question is whether basic impairment in visual processing gives rise to the deficits observed in social perception. In this context, previous research has shown that biological motion contains relevant social information, such as emotional states and intention, which is easily interpreted by healthy observers. Given that biological motion perception is an important source of social information, and that patients with SCZ have known visual perceptual impairment including motion processing deficits, it is possible that poor biological motion perception meaningfully impacts social perception among individuals with SCZ. While previous studies have documented preliminary evidence of biological motion processing deficits in this population, there is a current lack of understanding regarding the basic visual perceptual mechanisms that may underpin this impairment, including the importance of basic visual motion processing with respect to biological motion. Moreover, the ability of individuals with SCZ to extract relevant social information from biological motion, and its relationship with social perception more generally, have yet to be investigated. Thus, the specific aims guiding the current thesis were to examine whether basic visual motion processes may give rise to biological motion deficits and to examine the ability of individuals with SCZ to extract
social information, in the form of emotion, from biological motion. Several experimental tasks were used to examine these aims. Overall, the results from this thesis confirm that individuals with SCZ have difficulty perceiving biological motion; however, this deficit was not specific to biological motion, but instead reflected more widespread visual motion processing deficits, including impairment in global coherent motion perception. Additionally, results from this thesis suggest that individuals with SCZ demonstrated disproportionate difficulty extracting social cues, in the form of emotion, from biological motion, and that this deficit was related to perceiving unambiguous expressions of emotion. In contrast, the discrimination of more subtle or ambiguous emotion was relatively preserved. Moreover, impairment in biological motion processing was found to be unrelated to social perceptual abilities among individuals with SCZ. These experiments provide interesting suggestions regarding clinical approaches to treatment and remediation, although further research is needed to fully understand the brain- behaviour mechanisms underlying SCZ-related deficits in biological motion processing.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: As people navigate though day-to-day life, they encounter many objects in the world that move, such as other people. Research has shown that humans are adept at discriminating human movement and accurate in discerning the emotional states of other people based on this movement. These observations have lead researchers to speculate that, because biological motion is both easy to discriminate and emotionally informative, it plays an essential role in social processing among humans. Research has shown that individuals with Schizophrenia have difficulty understanding social environmental cues, such as the emotions of others. As such, this thesis aims to determine first, whether people with Schizophrenia have difficulty identifying human motion, and second, if they are able to identify emotions embedded within human motion. This thesis will help researchers understand and explain deficits in social perception among people with Schizophrenia.


title: PHD THESIS: CONTROLLED DIFFUSION SOLIDIFICATION PROCESS (CDS) OF AL-7XXX WROUGHT ALLOYS: HEAT TREATMENT,MICROSTRUCTURE, AND MECHANICAL PROPERTIES

contributor:
SHANKAR, SUMANTH
Mechanical Engineering

subject: Casting, Solidifcaition, Aluminum, Physical Metallurgy, Mechanical Metallurgy, Strengthening Model, Aluminum Wrought Alloys, Aluminum 7xxx Series, Al-Zn-Mg-Cu

abstract: Casting, Solidification, Aluminum, Physical Metallurgy, Mechanical Metallurgy, Strengthening Model, Aluminum Wrought Alloys, Aluminum 7xxx Series, Al-Zn-Mg-Cu

abstract:
Over the past decades, researchers in casting fields, especially in semi-solid metal state, have endeavored to find new ways to enable the Al wrought alloys of casting using the conventional casting processes; mainly in order to improve the product properties and decrease the product cost. The thixoforming and rheocasting processes have been presented as ways by which the microstructure of Al-base wrought alloys can be changed into non-dendritic, which in turn can lead to improvement to the mechanical properties. This can be because the effect of the non-dendritic microstructure on the mechanical properties of the material. Unfortunately, these processes have proved to be cost prohibitive and be a bit complicated for commercial applications. Further, conventional casting of Al-base wrought alloys along with their superior properties and performance have been a challenge for foundry industry due to the main disadvantage of hot tearing or hot cracking during solidification process. This can render the cast component ineffective. To overcome the disadvantages of thixoforming and rheocasting processes, Controlled Diffusion Solidification (CDS) process was innovated mainly to enable casting of aluminum wrought alloys with a non-dendritic morphology of the primary Al phase in the resultant cast microstructure and thus alleviating the problem of hot tearing and obtaining a cost effective product with improved mechanical properties. The CDS is a simple process involving mixing of two precursor alloys of different thermal masses (temperature and solute) and subsequently casting the resultant mixture of the desired solute composition and temperature as a near net shaped cast product. The process can easily be commercialized with a marginal capital cost required for set up such as the addition of an extra holding furnace. Further, the CDS process would prove itself to be unique in its ability to cast Al-based wrought alloys into near net shaped components without additional processes and cost.
The originality of this study is to present a viable casting process for the Al-7xxx wrought alloys (Al-Zn-Mg-Cu); by which the Al-7xxx family alloys are presented in cast condition to have an acceptable uniaxial property range that is comparable with their wrought counterparts.
This study presents the process and alloy parameters necessary for the casting of Al-7xxx wrought alloys (Al-Zn-Mg-Cu), by using the CDS process coupling with tilt pour gravity casting (TPGC) machine. The uniaxial tensile mechanical properties of several Al-7xxx CDS castings under various heat treatment conditions, namely, solutionizing (T4), peak aged (T6) and annealing (O), necessary for development of an ageing process on the material were investigated and presented. The tilt pour gravity casting process coupled with the CDS technology was employed to demonstrate the ability to cast Al-7xxx wrought alloys into high integrity components with high strength and ductility. The microstructure characterization was carried out by Electron Microscopy (TEM, SEM and EDS) and DSC test experiments for all the as cast (F), T4, T6 and anneals (O) conditions of the CDS cast components. Also, the predictive capabilities for the yield strength of Al 7xxx alloys CDS cast components was investigated using structural-properties modeling for the various strengthening effects that are recently proposed specifically for the Al-7xxx wrought counterparts.
The study has successfully led to a more in-depth understanding of the innovative CDS casting process by applying it to several compositions of Al-7xxx wrought alloys in an industrial scale CDS casting experiments, using tilt pour gravity casting (TPGC) machine. This will hopefully lead us to a clearer path towards commercializing the CDS process and obtaining a viable casting process for Al-base wrought alloys into near net shape components without much change to economics of the casting process.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: The Effects of Diet and Altered Expression of the Keap1/CncC Pathway on Secretion of Organic Toxins by Malpighian Tubules of Drosophila melanogaster

contributor:
O'Donnell, Michael
Biology

subject: Keap1/CncC Drosophila Malpighian tubules dietary toxins

abstract: The Keap1-Nrf2 pathway is a major upstream regulator of xenobiotic detoxification. In Drosophila, directed activation of the protein complex of Keap1 and CncC (the homolog of human Nrf2) in principal and stellate cells of the Malpighian (renal) tubules confers resistance to lethal doses of the pesticide malathion, which is metabolized into organic anions. Dietary exposure to organic anions such as salicylate (10 mM) causes increases in fluid secretion rate and salicylate flux across Malpighian (renal) tubules. Here we used salicylate-selective microelectrodes and Ramsay assays to determine the role of Keap1/CncC in regulating these responses. Fluid secretion rate and salicylate flux across tubules isolated from adults with directed activation of Keap1/CncC in the principal cells are comparable to the values from salicylate-fed controls. Fluid secretion rate, concentration of salicylate in the secreted fluid and salicylate flux did not differ significantly between tubules isolated from adults with directed activation of Keap1/CncC in the principal cells reared on a diet containing salicylate and those reared on control media, indicating that the detoxification pathway was activated regardless of the presence of dietary salicylate. This is in contrast to the significant increase in fluid secretion rate and salicylate flux between tubules isolated from salicylate-fed adults and adults reared on a control diet with directed activation of Keap1/CncC in the stellate cells, supporting previous studies that demonstrated the inability of stellate cells to transport organic anions. Taken together, these results suggest a role for Keap1/CncC in upregulating fluid secretion in response to the presence of dietary organic anions.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: The Keap1-Nrf2 pathway is a major upstream regulator of xenobiotic detoxification. In Drosophila, directed activation of the protein complex of Keap1 and CncC (the Nrf2 homolog) in principal and stellate cells of the Malpighian (renal) tubules confers resistance to lethal doses of the pesticide malathion, which is metabolized into organic anions. Dietary exposure to organic anions such as salicylate (10 mM) causes increases in fluid secretion rate and salicylate flux across Malpighian (renal) tubules that are comparable to tubules isolated from adults with activated Keap1/CncC reared on a salicylate-free diet. This suggests a role for Keap1/CncC in upregulating fluid secretion in response to the presence of dietary organic anions.


title: The Usability Testing of the Web Accessible Population Pharmacokinetics Service- Hemophilia

contributor:
Iorio, Alfonso
McKibbon, Ann
Holbrook, Anne
eHealth

subject: usability, hemophilia, pharmacokinetics, system usability scale, think aloud

abstract:
Hemophilia is a genetic disorder that is caused by deficiencies in coagulation factor VIII and factor IX. Optimal management of hemophilia requires tailoring the dose of treatment to the individual patient’s need. This tailoring is based on several clinical considerations, for example, bleeding phenotype and desired level of activity, and estimated individual pharmacokinetic (PK) parameters. While a classical PK approach would require several post infusion blood samples taken over multiple days, a population PK approach might enable individual assessment using fewer samples. Health information technologies can support implementation of sophisticated, easily available, point-of care resources to estimate PK values with a population approach. The Web Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo) is a proposal for such a solution, developed at McMaster University. Once tested, it will be offered to hemophilia centres worldwide.
The objective of the study was to investigate the ease of use (usability) of the WAPPS-Hemo web interface among clinicians and other people who treat hemophilia through two iterative cycles of usability testing.
The total number of participants was 13, and they were physicians, nurses and research coordinators. The think aloud technique was selected for testing to gain feedback and comments on the participants’ thought processes while interacting with the system and discover interface design problems. Additionally, the System Usability Scale (SUS) questionnaire was used to obtain data on user satisfaction.

The initial assessment of the prototypal WAPPS-Hemo interface with SUS reported a score of 70.5, which is considered an above average score. We received many useful suggestions through two iterations of user testing, ending with a final SUS score of 73 after implementation of the suggested improvements. Verbal feedback from users in the second round showed that users experienced an easier and more intuitive interaction with the system.

Usability testing and analyses were conducted in this study to discover user interface issues and to determine the usability and learnability of the WAPPS-Hemo service among various potential users. Through iterative cycles, application of the think aloud technique, and the SUS questionnaire, we optimized the usability of the WAPPS- Hemo program and have moved to implementation (June 2015).

abstract: Thesis

abstract: Master of Science (MSc)


title: Coagulation and Redispersion of CO2-Switchable Polymer Latexes of Low Glass Transition Temperatures

contributor:
Zhu, Shiping
Chemical Engineering

subject: chemical engineering, acrylic latexes, latex redispersion, surfactant-free emulsion polymerization

abstract: In this thesis, copolymer latexes comprised of various fractions of methyl methacrylate (MMA) and butyl acrylate (BA) were synthesized through surfactant-free emulsion polymerization. A carbon dioxide responsive comonomer, 2-(diethyl)aminoethyl methacrylate (DEAEMA) was also used with an equimolar amount of hydrochloric acid (HCl) to promote its partitioning into the water phase. Changing the MMA/BA fraction gave control over the resulting glass transition temperature of the particles. Following polymerization, the particles from the resulting latexes could be effectively coagulated be adding a small amount of caustic soda, and could be easily separated from water. After washing the particles with deionized water, CO2-redispersibility of the latex particles was evaluated as a function of their respective glass transition temperature. It was determined that coagulated particles higher in MMA content could be easily redispersed into carbonated water with the aid of ultrasonication, preparing stable latexes of the same solids content. For latex particles with a glass transition temperature below ambient conditions, coagulation led to the fusion of individual particles, which inhibited their ability to be redispersed. By conducting the coagulation and redispersion cycles at temperatures cold enough for the BA-rich particles to be below their glass transition temperature, these same latex particles could be effectively redispersed. The relationship between the glass transition temperature of the latexes and their CO2-redispersibility provides guidance from a practical sense for the applicability of CO2-sensitive amine-functionalized molecules in developing industrially useful CO2-redispersible latex products.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: This work examines special type of coagulatable and redispersible latex paint that could potentially reduce the costs in storing and transporting latex paint products. After synthesizing the latex, the nanoscopic polymer particles that make up the latex could be easily coagulated by adding a small amount of sodium hydroxide. Following this, water could be removed and a condensed form of the paint was obtained. The ability to redisperse the particles back into carbonated water was subsequently examined based on the softness of the polymer particles by synthesizing a series of latexes with different fractions of methyl methacrylate (MMA) and butyl acrylate (BA). After synthesis, the latexes that contained higher fractions of MMA were comprised of particles that were less soft than the BA-rich latexes, which made the redispersibility of these particles much easier. Upon coagulation, BA-rich particles fused together upon contact and could not be separated, hence inhibiting their redispersibility. When these same BA-rich latex particles were coagulated at colder temperatures, fusion was inhibited and the redispersibility of particles was greatly improved. Overall, the particles were found to be redispersible if the glass transition temperature of polymer chains within the particles was lower than ambient temperature. Since softer polymer particles are often used for latex paint-based applications, this work provides important and relevant insight in the development of industrially useful CO2-redispersible products.


title: League of Legends: Players and Esports

title: The Work of Professional Players in League of Legends Esports

contributor:
Goutor, David
Labour Studies

subject:
Esports
League of Legends
Immaterial labour
Digital Labour
Playbour

abstract: Esports gaming is a new subject within various fields of research. Typically, research explores the relationships between games and its players or the developers. By contrast this thesis examines the highest level of play within gaming, professional players. To do so, it utilizes the example of League of Legends. Created in 2009, League of Legends has rapidly grown to become one of the largest online multiplayer games with a massive Esports scene that matches or exceeds that of traditional sports such as Basketball or Baseball. But what factors contribute to this sudden rise in League of Legends Esports popularity and how have professional players adjusted over the years? This thesis explores these questions and the overall evolution of professional teams and League of Legends over the course of its Esports growth. It finds that League of Legends is unique in its use of the immaterial labour and digital labour of professional players. Through a concept called the “Meta”, League of Legends is able to mimic traditional sports and maintain interest in its game. Further for professional players the existence and evolution of the “Meta” sharply influences the need for organizational restructuring over the years. Players and teams become complex organizations in which players’ transition from gamers to become workers in Esports. Exploring the League of Legends Esports setting uncovers a unique combination of sport and work within a new digital context.

abstract: Thesis

abstract: Master of Philosophy (MA)

abstract: The goal of this work is to explore the lives and labour of League of Legends professional players. Created in 2009, League of Legends rapidly grew to be one of the most played and watched Esport game in the world. Professional players are often heralded as celebrities and their decisions impact the larger League of Legends and Esports community. This work examines the realities of Esports for professional players. It further analyzes the structure and organization of play and work in the League of Legends Esports setting. For the developer, Riot Games, Esports serves a variety of purposes and this thesis explores this and the contributions of Esports professionals to the development of the game.


title: Accuracy and Precision of Microelectronic Measuring Systems (MEMS)

contributor:
MacIntyre, Norma
Rehabilitation Science

subject:
Microelectronic Measuring System
Accuracy
Precision
Accelerometer
Gyroscope
Magnetometer

abstract:
Microelectronic Measuring Systems (MEMS) are being used to capture kinematic data in real-world environments. The benefits of using MEMS are their small size, relatively low cost (compared to an Optical Motion Capture System) and the ability to capture real-time data in almost any environment. The accuracy and precision of MEMS can be influenced by elements in their surrounding environment such as building materials (i.e., reinforced steel) and structural components (i.e., elevators). Recognizing the influence of the environment on MEMS output is important if the MEMS are to be used in real-world environments where subjects could navigate between various environments. MEMS can also be affected by dynamic motion therefore testing of the MEMS in the same conditions in which they are to be used will help to identify any issues prior to data collection.
The overall purpose of this thesis was to determine if the outputs of four Shimmer 2r MEMS were accurate and precise enough in static and dynamic conditions to use in a future study to assess gait activities of daily living in individuals with a unilateral transtibial amputation. In order to understand the effect of the environment on the MEMS, accuracy and precision were assessed in a rural environment (to reduce the effect of building materials and structural components) as well as the clinical environment where they will eventually be used for research. The MEMS were also evaluated in static and dynamic conditions to better understand how motion affected accuracy and precision.
The results of this study confirmed that the clinical environment affected the MEMS outputs. During the dynamic condition, the gyroscope output of one MEMS sensor was significantly different than the other devices indicating recalibration or possible exclusion from future studies. Prior to using MEMS in research, it is advisable to investigate the effects of the environment on the sensor outputs as well as assess the performance of the individual sensors.

abstract: Thesis

abstract: Master of Science Rehabilitation Science (MSc)

abstract: The overall objective of this thesis was to determine if four Shimmer 2r Microelectronic Measuring Systems (MEMS) were accurate and precise enough in static and dynamic conditions prior to their use in a future study to assess seven activities of daily living (including level walking, ramp walking and stairs) in individuals with a unilateral transtibial amputation in a clinical environment. To understand the effect the environment has on the MEMS, they were assessed in both a rural environment to reduce the effect of building materials, as well as the clinical environment where they will eventually be used for research. This study confirmed that the clinical environment affected the MEMS outputs, although these effects were deemed to be clinically insignificant for the intended purpose of these MEMS. Calibration as well as accuracy and precision assessment of MEMS should be executed in the conditions and environments in which they are to be utilized.


title: Electron Backscatter Diffraction of Gold Nanoparticles

title: Electron Backscatter Diffraction (EBSD) of Gold Nanoparticles

contributor:
Preston, John S.
Engineering Physics

subject: EBSD

subject: Electron Backscatter Diffraction

subject: Nanoparticles Nanowires Nano Nanostructures

subject: Scanning Electron Mincroscope Crystal Structure Gold AuNP Au NP

subject: microstructure

subject: x-ray diffraction xrd 2dxrd

abstract:
Electron Backscatter Diffraction (EBSD) is a well-developed technique used to perform quantitative microstructure analysis in the Scanning Electron Microscope (SEM); however, it has not been widely applied towards studying nanostructures. This work focuses on the use and limitations of EBSD in the characterization of Au nanoparticles on an MgAl2O4 substrate. Samples under investigation are prepared by depositing a thin film of Au on an MgAl2O4 substrate, and then finally heated in a furnace to induce dewetting and cluster formation.
The challenges of obtaining crystallographic information from nanoparticles using EBSD are qualitatively and quantitatively described through an evaluation of the quality of the diffraction pattern at various locations of the primary electron beam on the nanoparticle. It is determined that for a high quality Electron Backscatter Diffraction Pattern (EBSP), the production of diffracted backscattered electrons travelling towards the detector must be high and the depth of the source point must be low. The top of the nanoparticle, where the local geometry of the system is similar to the geometry of a macroscopically flat sample, is found to produce diffraction patterns of the highest quality. On the other hand, reversed-contrast EBSPs are observed when the beam is positioned near the bottom of the nanoparticle.
In addition, crystallographic information for each individual nanoparticle is gathered using EBSD. Each individual AuNP is observed to be single crystalline. Finally, the complete ensemble of crystalline orientations for individual nanoparticles is then compared to the global averaged crystallinity of the sample, as measured by X-ray diffraction. These results show that EBSD promises to be a powerful and robust technique in the characterization of nanoparticles.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: MORAL PHILOSOPHY AND THE DARWINIAN PROBLEM OF SOCIAL EVOLUTION

contributor:
Arthur, Richard
Philosophy

subject: Social Evolution; Moral Philosophy, Darwinian Theory

abstract:
Social behaviour is common in nature. Yet, for over a century and half, scholars have struggled in vain to offer a satisfactory account of its evolution under Darwinian natural selection. In this thesis I propose that three fundamental assumptions in the Darwinian explanation of social behaviour are at the root of the problem. They are: 1. The basic Darwinian philosophy that evolutionary change occurs by one inherent trait replacing another in an organism. 2. The collapse of social behaviour, in its entirety, into a single, narrow concept called “altruism.” 3. The assumption that such “altruism” arises from a mutation at a single gene locus, where it supplants “selfishness” as an alternative allele.
The thesis identifies some insights from Hume’s analysis of human morality and sociality that suggest the proper circumstances of social interactions in humans. We see from Hume’s analysis that nothing inherent in human nature needs to change in order to move beyond parenting to sociality. Hume identifies two principles in human nature — selfishness and empathy — that are the ultimate basis of human sociality. Empathy expands self-interest to include relatives and associates, but not strangers. And that suffices to form small, primitive human societies. For large, cosmopolitan societies, Hume suggests they are maintained only through human inventions such as governments and justice. Hume’s explanation precludes the need for a weaker “altruistic gene” to supplant a fitter “selfish gene” as a condition for social evolution, which has been the basis of the Darwinian explanatory difficulty.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Neuroprotection in a rotenone model of Parkinson's disease

contributor:
Niles, Lennard
Neuroscience

subject: Parkinson's disease, rotenone, intrastriatal, valproic acid, melatonin, neuroprotection, tyrosine hydroxylase, alpha-synuclein, medial forebrain bundle, substantia nigra, striatum

abstract: The pesticide/neurotoxin, rotenone, has been shown to cause systemic inhibition of mitochondrial complex I activity, with consequent degeneration of the nigrostriatal pathway, as observed in Parkinson’s disease.  A novel intrastriatal rotenone model of Parkinson’s disease was used to examine the neuroprotective effects of valproic acid (VPA) and melatonin, both of which are known to induce neurotrophic gene expression in the central nervous system via mechanisms which may involve epigenetic modulation.    In these studies, sham or lesioned rats were treated with either vehicle, VPA (4mg/mL), or melatonin (4µg/mL) in drinking water.   Results from a forelimb asymmetry test indicated a significant decrease in use of the contralateral forelimb in rotenone-infused animals, in the third week post-surgery, which was abolished by VPA treatment.  Apomorphine administration resulted in significantly higher ipsilateral rotation in rotenone-lesioned (12µg) animals, as compared to controls, which was attenuated by melatonin treatment.  Subsequent immunohistochemical examination revealed a decrease in tyrosine hydroxylase immunoreactivity within the striatum and substantia nigra of rotenone-infused animals.  VPA or melatonin treatment prevented this decrease in tyrosine hydroxylase in the striatum and substantia nigra.   Stereological cell counting indicated a significant decrease in dopamine neurons within the substantia nigra of rotenone-treated animals.   Importantly, this loss of dopamine neurons in rotenone-infused animals was blocked by chronic VPA or melatonin treatment.   A third study explored whether rotenone infusion into the medial forebrain bundle and substantia nigra in mice could provide a model of Parkinson's disease. Densitometric analysis revealed a significant depletion of tyrosine hydroxylase immunofluorescence within the ipsilateral striatum and substantia nigra of lesioned animals, and a significant bilateral overexpression of α-synuclein in the substantia nigra, as compared to control animals.  These novel findings support the use of intracranial rotenone as a Parkinsonian model, and provide a solid platform for future combinatorial therapeutic approaches with VPA and melatonin.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)