VictorJuiz/thesis huggingface dataset:
177Lu-labeled Gold Nanoparticles for Radiation Therapy of Locally Advanced Breast Cancer

Locally advanced breast cancer (LABC) occurs in about 10-15% of patients diagnosed with breast cancer (BC) and 30% of these patients have triple negative breast cancer (TNBC) that are often epidermal growth factor receptor (EGFR)-positive. The goal of the proposed research was design and evaluate preclinically a novel radiation nanomedicine for LABC composed of EGFR-targeted gold nanoparticles (AuNP) by covalently conjugating panitumumab and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) complexing 177Lu incorporated into a metal-chelating polymer (MCP) (177Lu-T-AuNP) which could be used as a neoadjuvant treatment to improve the outcome of patients with LABC. 177Lu-T-AuNP were efficiently internalized by EGFR-positive BC cells and were significantly more effective than 177Lu-labeled and non-targeted (NT)-AuNP for killing these cells. For radiation treatment of EGFR-positive tumours, both 177Lu-T-AuNP and 177Lu-NT-AuNP were intratumourally (i.t.) injected into athymic mice with MDA-MB-468 BC xenografts for comparison. Biodistribution studies showed that 177Lu-T-AuNPs exhibited 2-fold higher tumour retention than 177Lu-NT-AuNPs following i.t. injection at 48 h p.i. Both forms of radiolabeled AuNP were highly effective for inhibiting tumour growth without normal organ toxicity due to local tumour retention of both form of AuNP. To minimize the displacement of 177Lu-labeled MCP from AuNP, polyethylene glycol (PEG) ligands presenting a disulfide [177Lu-DOTA-PEG-ortho-pyridyl disulfide (OPSS)], a lipoic acid (LA) [177Lu-DOTA-PEG-lipoic acid (LA)] or multi-LA [PEG-pGlu(177Lu-DOTA)8-LA4] for multivalent binding were synthesized and the stability of MCP-AuNP complexes determined. In vitro challenge study with thiol-containing molecules or human plasma, PEG-pGlu(DOTA)8-LA4-AuNP were most stable. In whole body elimination study, elimination of radioactivity due to displacement of 177Lu-MCP from AuNP in mice injected with 177Lu-DOTA-PEG-OPSS-AuNP was more rapid, indicating that 177Lu-DOTA-PEG-OPSS-AuNP was less stable than two other forms of 177Lu-MCP-AuNP. Since MCP presenting a terminal multi-LA group provides the greatest stability, this conjugation chemistry is the most promising for construction of 177Lu-labeled and antibody-targeted AuNP for neoadjuvant treatment of LABC.

Keywords: 177Lu
Brachytherapy
Epidermal growth factor receptor (EGFR)
Gold nanoparticles
Locally advanced breast cancer (LABC)
Advisor: Reilly, Raymond M
Applications of Pascal Mixture Models to Insurance and Risk Management

This thesis studies the applications of Pascal mixture models in three closely related topics in insurance and risk management. The first topic is on the modeling of correlated frequencies of operational risk (OR) losses from financial institutions. We propose a copula-free approach for modeling correlated frequencies using an Erlang-based multivariate mixed Poisson distribution. Many properties possessed by this class of distributions are investigated and a tailor-made generalized expectation-maximization (EM) algorithm is derived for fitting purposes. The applicability of the proposed distribution is illustrated in an OR management context, where this class is used to model the OR loss. The accuracy of the proposed approach is analyzed using a modified real operational loss data set. The second topic is about multivariate count regression with application in modeling correlated claim frequencies. We propose a multivariate Pascal mixture regression model as an alternative to understand the association between multivariate count response variables and their covariates. We examine the many properties possessed by this class of regression. A generalized EM algorithm is derived for fitting purposes, which also provides the standard errors of the regression coefficients which are useful for inference. Its applicability is demonstrated by fitting an automobile insurance claim count data set. The third topic is about modeling and predicting the number of incurred but not reported (IBNR) claims in Property Casualty (P) insurance. We model the claim arrival process together with the reporting delays as a marked Cox process whose intensity function is governed by a hidden Markov chain. The associated reported claim process and IBNR claim process remain to be marked Cox processes with easily convertible intensity functions and marking distributions. Closed-form expressions for both the autocorrelation function (ACF) and the distributions of the numbers of reported claims and IBNR claims are derived. A generalized EM algorithm is obtained to estimate the model parameters. The proposed model is examined through simulation studies and is also applied to a real insurance claim data set. We compare the predictive distributions of our model with those of the over-dispersed Poisson model (ODP), a stochastic model that underpins the widely used chain-ladder method.

Keywords: Cox Process
Expectation-Maximization Algorithm
Finite Mixture of Pascal Distribution
Hidden Markov Models
Loss Reserving
Multivariate Frequencies
Advisor: Lin, Xiaodong S
Badescu, Andrei L
Lagrangian Relaxation Approaches to Cardinality Constrained Portfolio Selection

Portfolio selection with cardinality constraint is a process that creates a strict subset of assets from a large selection pool. The advantage of cardinality constraint is that fewer assets can reduce transaction costs and complexity of asset management. Also, this type of constraint can be used to mimic a benchmark portfolio (index) such as S 500. In this dissertation we study two different cardinality constrained portfolio selection problems, known as Index Tracking and Financial Planning. Index Tracking is a typical application of the cardinality constrained portfolio selection process and has attracted much attention from portfolio managers. However, replicating unpredictable market indices using limited available resource requires advanced modelling and optimization techniques in practice. This thesis aims to qualitatively investigate and analyze different types of index tracking problems and the associated optimal strategies. Firstly, we construct the tracking portfolio via a constrained clustering approach which considers various practical aspects such as transaction costs, turnover, and sector limits constraints. We show that the portfolio allocation can diversify between different sectors and reduce the portfolio risk fairly well. Next we address a cardinality constrained Financial Planning problem through Stochastic Mixed Integer Programming and extend the network flow structured framework to index tracking problem. Finally, we incorporate the cardinality restriction to a classical mean-variance based tracking model and build the robust counterpart via Robust Optimization. All developed models demand problem solvability due to the rapid increase in the number of variables and constraints for tracking real indices such as S 500. We design three dual decomposition algorithms, which allow different specific heuristics to be embedded, to quickly obtain high quality solutions for associated models. For example, Tabu Search was applied to solve the scenario sub-problems to speed up the Progressive Hedging algorithm for cardinality constrained financial planning problems. Our designed models are general enough to extend to many other management applications, and our accompanied decomposition algorithms are efficient enough to handle the cardinality constraint in these problems. The generated portfolios illustrate the effectiveness of our selection technologies and designed algorithms in terms of different performance metrics with respect to the market.

Keywords: Index Tracking
Lagrangian Relaxation
Portfolio Optimization
Risk Management
Advisor: Kwon, Roy H.
Two Teachers’ Changing Views and Practices through Implementation of Writer’s Workshop

Researchers continue to examine strategies on delivering effective writing programs for students (Graham, MacArthur, Fitzgerald, 2007). The writer’s workshop has gained significant attention, due to its emphasis on process-oriented and authentic writing (Atwell, 1998). This study involved two elementary teachers initiating writer’s workshop in their classes. While one teacher had never used this approach, the other had only started using it recently. In order to support teachers in their implementation, the researcher facilitated Professional Learning Communities, which provided participants a venue to discuss articles related to writer’s workshop, as well as critically reflect on their teaching. The purpose of this study was to examine how teachers’ thoughts on writing, and views of their roles as writing teachers changed over the research period. Additionally, the researcher aimed to determine the factors which influenced these changes, including the unique school context in which the study took place. The study employed a qualitative case study design, and data was collected over a five month period through observations of teachers, weekly seminars, monthly PLC sessions, as well as from teachers’ conferences with students. The researcher found that over the research period, teachers’ views of writing and roles as writing teachers became more closely aligned with the writer’s workshop approach. Four factors influenced these changing views, including teachers’ willingness to make changes in their teaching, the notion of collaboration, the success of writer’s workshop, and the school context. The study is beneficial to the field of writing because it provides insight into the experiences of new writer’s workshop teachers. Additionally, the study has important implications for leaders who wish to carry out change initiatives in their schools, as it provides them with information on the factors that may support or negate their efforts.

Keywords: case study
professional learning communities
teacher development
writer's workshop
writing pedagogy
Advisor: Stagg Peterson, Shelley
High-performance Nonlinear Piezoelectric Energy Harvesting in Compressive Mode

With the rapid development of low-power electronic devices such as wireless sensor networks, wearable devices and medical implants, the need for long-lifespan and high-efficiency power sources has become more and more pressing. The commonly used electrochemical batteries cannot meet the demand due to their limited capacity, low energy density, and maintenance and disposal requirements, which has spurred interest in the vibration energy harvesting technique. Over the past decade, many endeavors have been undertaken to improve the performance of energy harvesters, especially those using piezoelectric materials. Piezoelectric energy harvesters (PEHs) however, are still in the laboratory stage and cannot be widely deployed in practice. The main blocking factors stem from their low power output and poor environmental adaptability. This thesis aims to explore new methods to improve energy harvester performance in terms of power output, frequency bandwidth and directional sensitivity. Specifically, by taking advantage of the nonlinear dynamics of thin beams and the compressive mode of piezoceramics, a high-performance compressive-mode piezoelectric energy harvester (HC-PEH) is proposed. A multi-stage force amplification mechanism is embedded into the coupling system, which significantly increases the voltage responses. Finite element analysis and analytical modeling are conducted to analyze the stress state, the force amplification effect and the nonlinear characteristics of the system. Prototypes are fabricated and tested . The experimental data, closely matched with the analytical estimations, demonstrates great performance enhancement. The bandwidth is effectively extended by the strong nonlinear responses. A maximum power 54.7 mW is generated under an acceleration of 4.9 m/s^2, which is about one order of magnitude higher than the state of the art. Furthermore, this study proposes a simple method to enhance the tailorability of energy harvesters by shifting the dynamic responses between the hardening and softening nonlinearity. To deal with the unidirectional sensitivity issue, a multi-directional compressive-mode piezoelectric energy harvester (MC-PEH) is developed. Theoretical and experimental studies demonstrate that the MC-PEH is capable of isotropically harnessing vibration energy from multiple directions. Apart from the structural aspect, new piezoelectric materials (PMN-PT PZN-PT) and interface circuits (SSHI) have also been investigated to improve the efficiency of whole energy harvesting systems.

Keywords: Energy harvesting
Force amplification
Low-power circuits
Nonlinear vibration
Piezoelectric
Smart material
Advisor: Zu, Jean W
Measuring Student Engagement Using Learning Management Systems

In less than two decades, learning management systems (LMS) have gone from being a rarity to having near-ubiquitous presence on Canadian college campuses. This wide-spread adoption of LMS technology has fundamentally changed the learning environment for today’s campus-based college student, yet there is a lack of research that investigates how students engage with the learning environments created by the prevalent use of these systems. The purpose of this study is to explore the relationship between campus-based students’ perceived level of engagement in LMS an online learning environment and their online behaviour as measured by log data for various LMS activities. Additionally, this study examined faculty members’ use of an LMS and the impact of that use on students’ engagement and students’ use of the LMS. The results of the analysis reveal no correlation between students’ online engagement as measured by the Student Engagement Questionnaire (SEQ) and frequency counts of LMS activities. Small correlations were found between students’ estimates of their LMS activity in discussion forums and their overall SEQ score. There was no difference in the mean SEQ score between groups of survey respondents based on faculty use of the LMS, but some differences in student estimates of their activity in discussion forums were found between student respondents grouped by age and gender.

Keywords: academic analytics
learning analytics
learning management systems
LMS
online
student engagement
Advisor: Childs, Ruth
Duties as Assigned: How Principals' Leadership Practices Influence their Vice-principals' Leadership Self-efficacy

This study examines the potentially critical role elementary school principals play in the leadership development of their vice-principals. A growing body of research supports the important role principals might assume in the leadership development of vice-principals. Reports from the field, however, indicate that the vice-principalship does not adequately prepare vice-principals to become school principals. This research attempts to resolve this apparent tension by asking: “How do principals’ leadership practices influence the leadership self-efficacy of elementary vice-principals?” Using self-efficacy as an indicator of vice-principals’ leadership development, this research examines the effects of specific leadership practices by elementary school principals (aligned with the four sources of self-efficacy: enactive mastery, vicarious experience, verbal feedback, and physiological states) on vice-principals’ leadership development in three domains: management, instructional leadership, and moral leadership. This study adopts a mixed methods, sequential explanatory, approach. An online survey of vice-principals in English school districts in Ontario was conducted. Then, 15 interviews of purposively selected participants (from the online survey) were completed based on the results of the initial phase of the research. The findings of the study illustrate a small but significant effect of principals’ leadership practices on vice-principals’ leadership self-efficacy. A strong relationship between principals’ leadership practices and vice-principals’ opportunities to lead within their schools suggests that principals’ leadership practices may also capture a certain style of leadership that is conducive to vice-principals’ leadership development. The qualitative phase of this research suggests that these elements are: autonomy, trust, collaboration, and respect. How these elements influence the working environment and relationship of vice-principals should be considered in future research. This research supports the importance of self-efficacy when considering leadership development in Ontario schools, both as a potential measure of leadership effectiveness and as a means of improving leadership performance in schools, particularly as formal school leadership influences school performance and student achievement.

Keywords: Leadership Practices
Principal
Self-efficacy
Vice-principal
Advisor: Campbell, Carol
The Internet and Childhood Immunizations in Canada

The Internet has been identified as a potential determinant in parental fears of immunization and subsequent sub-optimal immunization coverage. Facebook is the most popular social media (SM) platform in Canada, and as more people abandon landlines, this platform presents an opportunity for novel recruiting of vaccine hesitant (VH) parents. In this thesis, I investigate Facebook as a tool to recruit VH Canadian parents and examine the determinants of vaccine hesitancy among Canadian parents, including the influence of the Internet. The aims are to describe the methods in studying health behaviours via SM; investigate Facebook as a tool to recruit VH parents compared to Random digit dialing (RDD) methods and describe their determinants of vaccine hesitancy; quantify the association between seeking vaccination information online and parental perception of risk on childhood immunization; and assess the vaccination sentiments and themes in an unsolicited online debate on immunization. My systematic review revealed limited research using SM to study health behaviours and limitations in terms of representativeness and validity. Notwithstanding, SM was shown to be a useful tool in gathering data from targeted populations. I recruited Canadian parents by Facebook advertisements linked to an online survey on childhood immunization, and compared methodological parameters, key demographics, and vaccine hesitancy indicators to a population-based RDD sample of Canadian parents. Facebook recruitment yielded a large sample size within a short time period and at lower costs compared to RDD recruitment, and was superior in reaching VH mothers with young children. Lack of knowledge/awareness and misperceptions on the risk of immunization were the most reported determinants of vaccine hesitancy. Multivariate ordinal regression on both datasets revealed the odds of perceiving vaccines as less safe were significantly higher for parents who seek vaccination information online compared to parents who do not, after adjusting for income, Internet reliability, parental age and region. Analysis of online user-driven comments revealed the main themes in the anti-vaccination comments were inaccurate information and misperceptions on the risks of immunization. The majority of the pro-vaccination comments communicated the risks of not vaccinating, and judgments on the knowledge level of non-vaccinators. The results provide evidence to inform the development of targeted interventions on immunization.

Keywords: Canadian parents
Immunization
Social media
Vaccine hesitancy
Advisor: Crowcroft, Natasha S
What's Good for the Goose? Examining the Impact of Gender-neutral and Gender-specific Factors in the Assessment and Treatment of Female and Male Justice-involved Youth

In response to female youths’ increased visibility in the legal system, more attention has been paid to understanding girls’ pathways to justice system involvement, risk for re-offending, and rehabilitative needs. Widely-used risk assessment and case management tools based on the Risk Need Responsivity (RNR) framework are largely gender neutral. Gender-responsive scholars have long advocated for the importance of additional gender-specific factors in guiding the assessment and treatment of female justice-involved youth. The dissertation is comprised of two papers which examine the contribution of proposed gender-specific factors alongside well established RNR factors in the prediction of recidivism, and how service provision aimed at intervening with these factors impacts recidivism for both male and female justice-involved youth. Paper 1 explores the relationship between trauma, criminogenic needs and recidivism. I first sought to define the distinct constructs often referred to under the umbrella term ‘trauma’: PTSD symptomology, maltreatment, and childhood adversity. The relationships between these factors, well-established criminogenic needs, and recidivism were examined and compared in a matched sample of 50 female and 50 male justice-involved youth. Females were significantly more likely than males to have experienced multiple forms of maltreatment. Several maltreatment and childhood adversity factors were significantly and positively related to criminogenic needs. PTSD symptomology and childhood adversity were not significant predictors of recidivism; however, maltreatment was the strongest predictor of recidivism for both males and females in a model that included well established risk factors. Gender was not found to be moderating the relationship between maltreatment and recidivism. Implications of the findings for theory and practice are discussed. Paper 2 examines the contribution of both criminogenic needs and several additional proposed ‘female’ gender-specific factors to risk assessment and rehabilitative treatment. Female youth were more likely than male youth to have proposed ‘female’ gender-specific needs but these needs alone did not predict recidivism. Successfully matching services to youths’ criminogenic needs predicted reduced recidivism for both male and female youth. For youth who had ‘female’ gender-specific needs, successful matching of services to these needs also predicted reduced recidivism for both genders. Theoretical and practice implications of these results are discussed.

Keywords: Gender-Specific
Justice-Involved Youth
Risk Need Responsivity
Trauma
Young Offenders
Advisor: Peterson-Badali, Michele
Skilling, Tracey