Physical Sciences and Mathematics Commons^™

The Atmospheric Chemistry Of Magnetic Bp Stars, Jeffrey D. Bailey

Electronic Thesis and Dissertation Repository

The chemically peculiar magnetic A- and B-type (Ap/Bp) stars are characterised by large overabundances, of the order of 10^2 and 10^4 times the Sun, of Fe-peak and rare earth elements, respectively. Further, they possess strong, ordered magnetic fields (of order 1 kG) that are roughly dipolar in nature. We present in-depth investigations of magnetic Ap/Bp stars, ranging from detailed analyses of specific stars to larger surveys aimed at studying stratification and atmospheric abundance evolution.

For HD 133880 and HD 147010, we offer complete investigations of their magnetic fields and chemical abundance distributions. For each star, a simple magnetic field model …

In Situ High-Pressure Studies Of Ammonia Borane Derivatives By Vibrational Spectroscopy, Zhihao Yu

Electronic Thesis and Dissertation Repository

Hydrogen has been regarded as a promising candidate to replace the conventional fossil fuel, and thus attracted enormous research efforts. However, hydrogen storage remains to be a big challenge to its practical applications. Consequently, the investigation of suitable hydrogen storage materials has become a highly active research field. Here we reported the first high pressure studies of three promising hydrogen storage materials, N(CH₃)₃BH₃, NH(CH₃)₂BH₃ and NaNH₂BH₃ by Raman and IR spectroscopy.

First, N(CH₃)₃BH₃ was studied at room temperature and pressures up …

Approaches Toward Combining Positron Emission Tomography With Magnetic Resonance Imaging, Geron A. Bindseil

Electronic Thesis and Dissertation Repository

Positron emission tomography (PET) and magnetic resonance imaging (MRI) provide complementary information, and there has been a great deal of research effort to combine these two modalities. A major engineering hurdle is that photomultiplier tubes (PMT), used in conventional PET detectors, are sensitive to magnetic field. This thesis explores the design considerations of different ways of combining small animal PMT-based PET systems with MRI through experimentation, modelling and Monte Carlo simulation. A proof-of-principle hybrid PET and field-cycled MRI system was built and the first multimodality images are shown. A Siemens Inveon PET was exposed to magnetic fields of different strengths …

On Degeneracies In The Family Of Fibres Of A Complex Analytic Mapping, Hadi Seyedinejad

Electronic Thesis and Dissertation Repository

Failure of some (important) properties of a holomorphic mapping manifests itself as degeneracies in the family of fibres of the mapping. Among these properties are openness and flatness. The first goal in this thesis is to develop criteria that allow one to effectively (i.e., computationally) detect such degeneracies in the family of fibres, and in addition, that are applicable to the case of mappings with singular targets. Particularly regarding flatness, no such algorithms that work in the general setting of singular targets were known before. We prove that a mapping (with a locally irreducible target) is flat (resp. open) if …

The Role Of Metallothionein In Zinc Homeostasis, Kelly L. Summers

Electronic Thesis and Dissertation Repository

The structure of the unique metal-binding protein, metallothionein (MT), consists of two metal-thiolate-clustered binding domains; the β-domain binds up to three divalent metals and the α-domain binds four. The mechanisms through which the metals are bound and arranged into domains, as well as the function of MT in metal ion homeostasis, remains largely unknown. By utilizing electrospray ionization mass spectrometry (ESI MS) to identify each species, and by comparing the data with simulations, MT 1a was found to bind Zn²⁺ non-cooperatively. Through a competition experiment between MT and its individual domain peptides, MT was proposed to bind Zn^{2+ …}

Donor-Acceptor Cyclobutanes And Their Application For Heterocycle Synthesis And Progress Towards Biselide A, Benjamin Machin

Electronic Thesis and Dissertation Repository

The chemistry of cyclobutane-1,1-diester has been investigated with aldehydes and alkyne reaction partners independently of each other. Under Yb(OTf)₃ catalysis donor-acceptor cyclobutanes undergo a formal [4+2] cycloaddition with aldehydes to generate tetrahydropyrans exclusively in a cis disposition. Activated aldehydes were generally well tolerated giving tetrahydropyrans in moderate to good yields (51 - 89%) whereas less reactive congeners gave lower yields (51 - 72%).

All carbon reaction partners were used in BF₃·OEt₂ mediated conditions to afford an unexpected 2,3-dihydrooxepine product resulting from alkynyl addition and rearrangement. Aryl acetylenes were compatible with the reaction conditions and moderate yields …

Cycloaddition Chemistry For The Synthesis Of Heterocyclic Compounds And Progress Towards The Total Synthesis Of Grandilodine A, Andrew C. Stevens

Electronic Thesis and Dissertation Repository

This thesis describes three separate research projects within the broad topic of synthetic organic chemistry. The synthesis of alkyl-substituted siloles and their reactivity in Diels-Alder chemistry is reported. Furthermore, the cleavage of the bicyclic adducts by Tamao-Fleming oxidation has been achieved which reveals a highly substituted cyclohexene-1,4-diol structure.

The second chapter describes the cycloaddition chemistry of alkoxy-activated cyclobutane dicarboxylates with aldehydes, nitrones and nitrosoarenes. The cycloaddition occurs, in the case of aldehydes, with uniformly high diastereoselectivity to afford tetrahydropyrans in good to excellent yield. When nitrones were used as the dipolarophile the cycloaddition occurs in a rather unselective manner though …

Eigenvalue Methods For Interpolation Bases, Piers W. Lawrence

Electronic Thesis and Dissertation Repository

This thesis investigates eigenvalue techniques for the location of roots of polynomials expressed in the Lagrange basis. Polynomial approximations to functions arise in almost all areas of computational mathematics, since polynomial expressions can be manipulated in ways that the original function cannot. Polynomials are most often expressed in the monomial basis; however, in many applications polynomials are constructed by interpolating data at a series of
points. The roots of such polynomial interpolants can be found by computing the eigenvalues of a generalized companion matrix pair constructed directly from the values of the interpolant. This affords the opportunity to work with …

Analysis Of Re-Advanceable Mortgages, Almas Naseem

Electronic Thesis and Dissertation Repository

According to Canadian tax law the interest payments on loans used for investment purposes are tax deductible while interest on personal mortgage loans is not. One way of transforming from non-tax deductible to tax deductible interest expenses is to borrow against home equity to make investments. This can be achieved through a re-advanceable mortgage and has been promoted by personal financial planners as a way of significantly decreasing the time required to pay off a mortgage and the associated total interest cost. However, the notion of risk associated with the investment holdings is not emphasized. Using simulation we study the …

Multiple Approaches For Assessing Mangrove Biophysical And Biochemical Variables Using In Situ And Remote Sensing Techniques, Francisco Javier Flores De Santiago

Electronic Thesis and Dissertation Repository

Mangrove forests are important ecosystems and play a key role in maintaining the equilibrium in coastal lagoons and estuaries. However, in recent years, there has been a considerable loss of mangrove extension due to anthropogenic activities. Recent studies suggest that multiple in situ and remote sensing approaches must be carried out to understand the dynamics in these complex ecosystems. Therefore, the objective for this PhD dissertation is to develop multiple techniques for monitoring the seasonal biophysical and biochemical conditions of the mangrove forests. Particular objectives will include: i. Test the feasibility of using a Chlorophyll Content Index from a …

Degradation Kinetics And Functional Design Of Linear Self-Immolative Polymers, Ryan A. Mcbride

Electronic Thesis and Dissertation Repository

Linear self-immolative polymers display a potential to address many of the limitations in the control over the degradation process in traditional biodegradable polymers. These materials are unique relative to most degradable 
polymers, in that they undergo end-to-end depolymerization in
 response to the cleavage of a stabilizing end-capping agent. Although one of their cited 
attributes is a dependence of their degradation time on chain length, no conclusive study has been conducted to demonstrate and study this 
effect. Using a previously reported linear self-immolative backbone derived from alternating 4-hydroxybenzyl alcohol and N,N’-dimethylethylenediamine spacers, this work offers the first conclusive study demonstrating …

Butyl Rubber-Aliphatic Polyester Graft Copolymers For Biomedical Applications: Synthesis And Analysis Of Chemical, Physical And Biological Properties, Bethany A. Turowec

Electronic Thesis and Dissertation Repository

Biomaterials can be used in a wide variety of medical applications owing to their breadth of characteristics that can be imparted by varying their chemical structures. Butyl rubber (IIR), which is a copolymer of isobutylene (IB) and small percentages of isoprene (IP), is particularly attractive as a biomaterial because of its elastomeric mechanical properties, biocompatibility, impermeability and high damping characteristics. IIR is typically vulcanized through chemical-based crosslinking mechanisms. However, these methods are not acceptable for biological applications. This thesis focuses on the synthesis of IIR-polyester graft copolymers by grafting biodegradable and biocompatible polyesters including poly(caprolactone) (PCL) and poly(d,l-lactide) (PDLLA) to …

Microbially Induced Magnesium Carbonation Reactions As A Strategy For Carbon Sequestration In Ultramafic Mine Tailings, Jenine Mccutcheon

Electronic Thesis and Dissertation Repository

The atmospheric carbon dioxide (CO₂) concentration has increased due to anthropogenic fossil fuel combustion, causing higher global temperatures and other negative environmental effects. CO₂ sequestration through carbonate mineralisation provides a stable, long term carbon sink. A natural hydromagnesite playa (Atlin, British Columbia, Canada) demonstrates the ability of phototrophic microorganisms to accelerate magnesium carbonate mineralisation. The site’s biogeochemistry was modeled in a 10 m flow-through bioreactor carbonation experiment, allowing for hydromagnesite precipitation conditions to be refined. Ultramafic mine tailings are a target substrate for carbonation reactions due to their high magnesium content. A synthetic mine leach water, designed …

Maps Of Lessons Learnt In Requirements Engineering, Ibtehal Noorwali

Electronic Thesis and Dissertation Repository

Both researchers and practitioners have emphasized the importance of learning from past experiences and its consequential impact on project time, cost, and quality. However, from the survey we conducted of requirements engineering (RE) practitioners, over 70\% of the respondents stated that they seldom use RE lessons in the RE process, though 85\% of these would use such lessons if readily available. Our observation, however, is that RE lessons are scattered, mainly implicitly, in the literature and practice, which obviously, does not help the situation. We, therefore, present ``maps” of RE lessons which would highlight weak (dark) and strong (bright) areas …

The Biogeochemical Cycling Of Gold Under Surface And Near-Surface Environmental Conditions, Jeremiah P. Shuster

Electronic Thesis and Dissertation Repository

The mobility of gold at near-surface environmental conditions, e.g., supergene weathering environments, lateritic weathering systems, saline to hypersaline systems and placer gold environments, takes place as oxidised, soluble gold complexes and as reduced elemental gold. The transformation between aqueous and solid states of gold is attributed to the varying geochemical conditions that occur in dynamic environments that are catalysed in part by the biosphere. The primary focus of this research is the investigation of biogeochemical processes that contribute to the cycling of gold using laboratory models to represent various natural systems including chemolithotrophic bacteria, e.g., iron-oxidising bacteria, and heterotrophic sulphate-reducing …

Novel Thiophene Supported N,N'-Chelating Ligands And Their Main Group Compounds, Jacquelyn T. Price

Electronic Thesis and Dissertation Repository

Main group chemistry has advanced from studying fundamental curiosities, including low oxidation state, low-valent, p-block elements to tailoring these unique, reactive species for specific functional applications. This thesis examines the structure, bonding and reactivity of select group 13, 14 and 15 elements supported by N,N'-chelating ligands decorated with either thiophene, benzo[1,2-b:5,6-b']dithiophene or bis(2,5-dimethylthienyl)ethene substituents and allowing for subsequent reactivity and photophysical properties to be determined.

The synthesis of a new diamino ligand containing a thiophene ring in the backbone was used to support a 7-membered phosphenium cation. The 1:1 stoichiometric reaction between the amine:chlorophosphine was dependant on the substitution …

Localizing State-Dependent Faults Using Associated Sequence Mining, Shaimaa Ali

Electronic Thesis and Dissertation Repository

In this thesis we developed a new fault localization process to localize faults in object oriented software. The process is built upon the "Encapsulation'' principle and aims to locate state-dependent discrepancies in the software's behavior. We experimented with the proposed process on 50 seeded faults in 8 subject programs, and were able to locate the faulty class in 100% of the cases when objects with constant states were taken into consideration, while we missed 24% percent of the faults when these objects were not considered. We also developed a customized data mining technique "Associated sequence mining'' to be used in …

Representing Game Dialogue As Expressions In First-Order Logic, Kaylen Fj Wheeler

Electronic Thesis and Dissertation Repository

Despite advancements in graphics, physics, and artificial intelligence, modern video games are still lacking in believable dialogue generation. The more complex and interactive stories in modern games may allow the player to experience different paths in dialogue trees, but such trees are still required to be manually created by authors. Recently, there has been research on methods of creating emergent believable behaviour, but these are lacking true dialogue construction capabilities. Because the mapping of natural language to meaningful computational representations (logical forms) is a difficult problem, an important first step may be to develop a means of representing in-game dialogue …

Origins Of Stable Isotopic Variations In Late Pleistocene Horse Enamel And Bone From Alberta, Nicolle S. Bellissimo

Electronic Thesis and Dissertation Repository

Oxygen and carbon isotopic measurements of coevally formed bone and tooth enamel bioapatite from a modern equid show that these tissues record drinking water and diet isotopic signals in an identical fashion. Hence, data for both tissues can be combined to track movement, dietary changes, and seasonal variability over the animal’s lifetime, and climatic variability over longer time periods. This tool was tested for horses using ten paired tooth and bone samples to reconstruct conditions in Alberta during the Late Pleistocene. While post-mortem isotopic alteration confounded interpretation of the results, two key findings emerged: (i) pre- and post-Last Glacial Maximum …

Statistical Analysis Of Correlated Ordinal Data: Application To Cluster Randomization Trials, Ruochu Gao

Electronic Thesis and Dissertation Repository

Cluster randomization trials have become increasingly popular when theoretical, ethical or practical considerations preclude the use of traditional trials that randomize individual subjects. Although some methods for analyzing clustered ordinal data have been brought to wide attention, these are less developed as compared to methods for analyzing clustered continuous or binary outcome data. The aim of this thesis is to refine existing strategies which may be applicable to clustered ordinal data as well as extensions which have been previously considered only for clustered binary responses. The approaches include adjusted Cochran-Armitage tests using an ICC estimator, and correction and modification strategies …

Hybrid Lattice Boltzmann - Molecular Dynamics Simulations With Both Simple And Complex Fluids, Frances E. Mackay

Electronic Thesis and Dissertation Repository

The behaviour and properties of colloidal suspensions strongly depend on the interactions arising between the immersed colloidal particles and the solvent. However, modelling such interactions is not at all straightforward; the larger time and length scales experienced by the colloidal particles compared to the solvent molecules makes all-atom molecular dynamics (MD) simulations of such systems completely impractical. Therefore a coarse-grained representation of the fluid is required, along with a method to couple this fluid to the colloidal particles.

In the first part of this thesis, we propose a new method for coupling both point and composite MD particles to an …

Core Formation In Partially Ionized Magnetic Molecular Clouds, Nicole D. Bailey

Electronic Thesis and Dissertation Repository

Linear analysis of the formation of protostellar cores in planar magnetic interstellar clouds shows that molecular clouds exhibit a preferred length scale for collapse that depends on the mass-to-flux ratio and neutral-ion collision time within the cloud. This linear analysis can be used to investigate the formation of star forming clusters and the distribution of mass within star forming regions. By combining the results of the linear analysis with a realistic ionization profile for the cloud, we find that a molecular cloud may evolve through two fragmentation events in the evolution toward the formation of stars. Our model suggests that …

Seasonal Decomposition For Geographical Time Series Using Nonparametric Regression, Hyukjun Gweon

Electronic Thesis and Dissertation Repository

A time series often contains various systematic effects such as trends and seasonality. These different components can be determined and separated by decomposition methods. In this thesis, we discuss time series decomposition process using nonparametric regression. A method based on both loess and harmonic regression is suggested and an optimal model selection method is discussed. We then compare the process with seasonal-trend decomposition by loess STL (Cleveland, 1979). While STL works well when that proper parameters are used, the method we introduce is also competitive: it makes parameter choice more automatic and less complex. The decomposition process often requires that …

Comparison Of Option Pricing Between Arma-Garch And Garch-M Models, Yi Xi

Electronic Thesis and Dissertation Repository

Option pricing is a major area in financial modeling. Option pricing is sometimes based on normal GARCH models. Normal GARCH models fail to capture the skewness and the leptokurtosis in financial data. The variant GARCH-in-mean (GARCH-M) model is widely used in the option pricing literature. It adds a heteroskedasticity term to the mean equation, which is interpreted as a risk premium, and also incorporates a type of asymmetry.

Our goal is to compare option valuation between GARCH-M and ARMA-GARCH models with normal and non-normal, z-distributed innovations. The models are fitted to the historical return data, and risk neutral measures are …

An Architecture For Believable Socially Aware Agents, Arvand Dorgoly

Electronic Thesis and Dissertation Repository

The main focus of this thesis is to solve the believability problem in video game agents by integrating necessary psychological and sociological foundations by means of role based architecture. Our design agent also has the capability to reason and predict the decisions of other actors by using its own mental model. The agent has a separate mental model for every actor.

Mapping And Zircon Geochronology Of The Lyon Inlet Boundary Zone, Nunavut; A Crustal Scale Break In The Churchill Province, Nikolas B. Ganderton

Electronic Thesis and Dissertation Repository

An important aspect of geology is the understanding of processes that created and modified continents and their resources. Knowledge of the age of formation and metamorphism of crystalline crust is thus important, and has been pursued in a recently discovered crustal-scale boundary on the southern Melville Peninsula (Nunavut, Canada) through field mapping, U-Pb zircon geochronology and electron beam analysis. This >250km-long crustal feature is termed here the Lyon Inlet Boundary Zone (LIBZ). Three samples from a 15 by 20 km map area reveal a complex Archean history with the dominant granitoid unit crystallizing at 2770±38 Ma and metamorphosed at 2670±36 …

Joint Outcome Modeling Using Shared Frailties With Application To Temporal Streamflow Data, Lihua Li

Electronic Thesis and Dissertation Repository

Recently there has been tremendous interest in the development of tools for joint analysis of longitudinal data and time-to-event data. This has gained emphasis particularly in clinical studies, where longitudinal measurements on a response may be recorded along with a time-to-event outcome. Joint analysis of multiple outcomes beyond longitudinal and survival have also been considered, for example, joint analysis of a variety of generalized linear models including continuous and count data, or continuous and binomial data. With joint analysis of multiple outcomes, the interest may be analysis of one outcome conditional on the others, or, more typically, analysis of all …

A New Diagnostic Test For Regression, Yun Shi

Electronic Thesis and Dissertation Repository

A new diagnostic test for regression and generalized linear models is discussed. The test is based on testing if the residuals are close together in the linear space of one of the covariates are correlated. This is a generalization of the famous problem of spurious correlation in time series regression. A full model building approach for the case of regression was developed in Mahdi (2011, Ph.D. Thesis, Western University, ”Diagnostic Checking, Time Series and Regression”) using an iterative generalized least squares algorithm. Simulation experiments were reported that demonstrate the validity and utility of this approach but no actual applications were …

Nfa Reduction Via Hypergraph Vertex Cover Approximation, Timothy Ng

Electronic Thesis and Dissertation Repository

In this thesis, we study in minimum vertex cover problem on the class of k-partite k-uniform hypergraphs. This problem arises when reducing the size of nondeterministic finite automata (NFA) using preorders, as suggested by Champarnaud and Coulon. It has been shown that reducing NFAs using preorders is at least as hard as computing a minimal vertex cover on 3-partite 3-uniform hypergraphs, which is NP-hard. We present several classes of regular languages for which NFAs that recognize them can be optimally reduced via preorders. We introduce an algorithm for approximating vertex cover on k-partite k-uniform hypergraphs based on a theorem by …

Integrated Development And Parallelization Of Automated Dicentric Chromosome Identification Software To Expedite Biodosimetry Analysis, Yanxin Li

Electronic Thesis and Dissertation Repository

Manual cytogenetic biodosimetry lacks the ability to handle mass casualty events. We present an automated dicentric chromosome identification (ADCI) software utilizing parallel computing technology. A parallelization strategy combining data and task parallelism, as well as optimization of I/O operations, has been designed, implemented, and incorporated in ADCI. Experiments on an eight-core desktop show that our algorithm can expedite the process of ADCI by at least four folds. Experiments on Symmetric Computing, SHARCNET, Blue Gene/Q multi-processor computers demonstrate the capability of parallelized ADCI to process thousands of samples for cytogenetic biodosimetry in a few hours. This increase in speed underscores the …