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Photochemistry of a tert-butyl substituted biaryl
No full textThe presence of a bulky substituent in the 6-position of a phenol has been shown to increase the efficiency of excited state intramolecular proton transfer (ESIPT) reactions, in which the increased acidity of the excited phenol results in a proton transfer from the hydroxyl group to a basic site on the same molecule. In this research project, we tested the generality of this idea in another system by adding a t-butyl group to the 6-position of 2-(1-naphthyl)phenol (16). Compounds 16 and 6-t-butyl-2-(1-naphthyl)phenol (25) were prepared by a Suzuki coupling reaction followed by demethylation with BBr3, giving overall yields of 68% and 67%, respectively. Both were investigated using UV-Vis spectroscopy, product studies, mass spectrometry (MS) and fluorescence. MS and UV-Vis spectroscopy were used to estimate quantum yields.
Compound 25 successfully underwent ESIPT to the 2'-position and 7'-position followed by reverse proton transfer (RPT) and electrocyclic ring closure, respectively, with approximate quantum yields of ΦD = 0.28 and Φcyc = 0.025, giving Φtotal = 0.305. The overall ESIPT efficiency was similar for 16 and 25, however the relative efficiencies for ESIPT to the 2'- and 7'-positions were very different between the two compounds. The addition of the t-butyl group caused the efficiency of ESIPT to the 2'-position to approximately double, while the efficiency of ESIPT to the 7'-position decreased by a factor of 8. Fluorescence spectroscopy was used to gain insight into the S1 state of 25, and a mechanistic proposal to account for our observations is presented
Olfactory receptor neuron responses of eastern spruce budworm, Choristoneura fumiferana Clemens. (Lepidoptera: Tortricidae) to female sex pheromones and host volatiles
No full textThe spruce budworm (Choristoneura fumiferana Clemens), is a major defoliating pest of coniferous trees in North America. Defoliation of forests was limited to some degree in the early 1960s through the aerial application of DDT (dichlorodiphenyltrichloroethane). Over time, DDT and other broad-spectrum insecticides were replaced with insecticides that specifically target lepidopterous larvae ((Bacillus thuringiensis var. kurstaki, Btk) and tebufenozide). Since the 1950's, research on more effective management strategies has occurred. In recent decades, substantial advances in pheromone-mediated trapping and mating disruption technologies have provided researchers with renewed hope for novel population control strategies of C. fumiferana. While the chemical ecology of spruce budworm is continually being studied, a detailed study of the antennal sensilla in adults has yet to be completed. In this thesis, we review the state of knowledge of C. fumiferana chemical ecology and behavioral responses to chemical stimuli. Further, extracellular single sensillum recordings (SSR) were used to determine the response of olfactory receptor neurons (ORNs) in the antennal sensilla of male and female C. fumiferana to host plant volatiles, and female sex pheromones with a range of concentrations. Together, these data will improve knowledge of mechanisms by which adult C. fumiferana respond to pheromone and host plant volatiles and will provide insights that may improve development of IPM strategies based on the chemical ecology of spruce budworm
Forecasting COVID-19 case counts using deep learning
No full textProvincial health care systems are in need of forecasting models to combat viral infectious diseases such as COVID-19, which can estimate changes in the number of cases in advance. This information can be used to alert policymakers and health care management to understand the changes in a pandemic and to estimate the future demand for health services. This study uses machine learning and deep learning methods to determine the most important variables responsible for the transmission of the virus and to predict daily or 7-day moving average case counts up to one week in advance.
Data was collected and prepared into daily records containing the number of new COVID case counts, demographic data on those found positive with COVID, outdoor weather variables, indoor environmental variables; and human movement data based on cellular mobility, and public health care restriction data. Inductive Decision Tree (IDT) models were developed and tested to analyze variable importance and to determine the typical manner in which these variables interacted to predict daily case counts. Indoor relative humidity was found to be an important factor not typically considered in such studies.
Predictive models were then developed using two deep neural network approaches: Convolutional Neural Networks (CNN) and Long Short-Term Memory (LSTM) neural networks. A 5-fold chronological cross-validation approach was used to develop these models. The best LSTM models forecasted tomorrow's daily COVID case counts with 90.7% accuracy, and the 7-day rolling average COVID case counts with 98.1% accuracy using the test set data. We also developed LSTM models to forecast the next 7 days of daily COVID case counts. The best models were able to predict the Daily case counts of the test set with a mean accuracy
of 90.5% over all days with the lowest accuracy of 91.4% on the first day predict. Models forecasting the 7-day rolling average case counts had a mean accuracy of 92.5%, and 94.3% on first day (D+1) on the same test set
The apocalypse will not be colonized: crisis, monsters, and futurism in recent Indigenous narratives
No full textThis thesis investigates how recent Indigenous apocalypse narratives depict the crises of ecological collapse and late-stage capitalism. Drawing on Gerald Vizenor (Anishinaabe)'s theory of survivance as well as Jacques Derrida's theory of hauntology and Mark Fisher's concept of capitalist realism, the thesis argues that Anishinaabe writer Waubgeshig Rice's Moon of the Crusted Snow (2018), Mi'gmaq director Jeff Barnaby's Blood Quantum (2019), and Métis writer Cherie Dimaline's The Marrow Thieves (2017) each envision futures beyond the "end of time." The thesis is framed by the Mi'kmaq concept of Etuaptmumk, or Two-Eyed Seeing, and begins by developing a theory of "colonialist realism": the sense that colonialism is inevitable and viable in perpetuity. The chapters that follow examine how Rice, Barnaby, and Dimaline critique colonialist realism through their narratives of crisis and collapse, the colonial monsters that hunt Indigenous characters in each work, and the dreams that create Indigenous futurity beyond the apocalypse
Finding grace: feminine interrelationships in Alias Grace, Ana Historic, and in Another Place, Not Here
No full textThis thesis examines three works of what Hélène Cixous calls écriture féminine published by Canadian women in the last two decades of the twentieth century. Through the analysis of Margaret Atwood's Alias Grace, Daphne Marlatt's Ana Historic, and Dionne Brand's In Another Place, Not Here, I argue that the feminine interrelationships in these novels work to resist various patriarchal and colonial power structures. This work draws on and extends Marie Carrière's argument in Writing in the Feminine in French and English Canada that ethical interrelationships of reciprocity between the self and other underpin feminine writing.
In Chapter One, I argue that Atwood triangulates Grace Marks' feminine interrelationships in Alias Grace through her relations with men. The intervention of men in Grace's relationships restricts her agency and leads Grace to resist male dominated narratives about her life by engaging in a kind of feminine writing of her own: the creation of a quilt. Chapter Two turns to the creative feminine interrelationships in Ana Historic to argue that Annie Anderson's reconfigured relationships and life enable her to reject language's and history's heteronormative expectations and continual repression. This chapter contends that Annie's rejection of these expectations propels her into a feminine space outside of the male gaze and demonstrates how interrelationships not only aid women in controlling their own narratives but their sexualities as well. Finally, Chapter Three examines how the feminine interrelationships of reciprocity in In Another Place, Not Here force Brand's characters to collide with seemingly insurmountable patriarchal and colonial power structures and barriers, such as racism and slavery, while enabling these characters to resist these structures, albeit in drastically dissimilar ways. Through the differing depictions of rejection in Atwood's, Marlatt's, and Brand's novels, this thesis aims to demonstrate how race, sexuality, and class, can change the way feminine interrelationships are displayed in writings in the feminine
Associations between fatalistic withdrawal from life and physical health
No full textAccording to Terror Management Theory (TMT), our awareness of our own eventual death and our helplessness to prevent it produces a large amount of existential anxiety in all of us. Because anxiety is unpleasant, we strive to find ways to ease this anxiety by either engaging with goals that provide life with meaning, or by withdrawing from all life-sustaining actions entirely. The current study aims to build on research by Hayes et al. (2016) to determine if fatalistic withdrawal and comorbid depression might precipitate changes in physical health that hasten death. This question is examined using a longitudinal, cross-lagged approach that follows 61 individuals over the course of four months. Data were analyzed using multiple linear regression and yielded a significant effect of past physical health on current desire for life, where an increase in physical illness predicted a decrease in desire to live. However, no significant
relationship could be established between past desire for life and future physical health or health behaviours. Implications for the treatment of physical illness are discussed and areas for future research are identified
Comparative analysis of machine learning algorithms within the domain of charitable giving
No full textMassive data collection combined with advancements in computing technologies have rapidly progressed the field of predictive analytics. Modelling techniques which previously depended almost entirely on human input are now heavily automated. However, even with this automation, discretion is still often left to the data scientist to determine which techniques best suit a given purpose. Large discrepancies exist between the performance of machine learning algorithms, dependent upon the underlying data and application. One potential application for predictive analytics is in the field of charitable giving. Here, fundraisers must prioritize the allocation of their time and resources based upon the likelihood and significance of prospect donations. Similar methods can also be used to maintain rapports with established donors, by predicting when they might be likely to lapse, or which lapsed donor relationships might be re-established. Thus, a variety of scenarios exist within the field of charitable giving which stand to benefit from predictive analytics. In this thesis, we seek to perform a comparative analysis of an assortment of common machine learning algorithms in the context of charitable giving. These algorithms will be used to predict prospect/donor behaviour across four areas of interest: prospects who are likely to make a donation within six months, donors likely to lapse, previous donors likely to return, and one-time donors likely to make repeat donations
Sequential consolidation using multiple task learning, sweep rehearsal and CVAE generated pseudo examples
No full textA key component for a Lifelong Learning Agent is the integration or consolidation of new task knowledge with prior task knowledge. Consolidation requires a solution to several problems,most notably, the catastrophic forgetting problem where the development of representation for a new task reduces the accuracy of prior tasks. This research extends our prior work on consolidation using multiple tasks learning (MTL) networks and a task rehearsal or replay approach. The goal is to maintain functional stability of the MTL network models for prior tasks, while providing representational plasticity to integrate new task knowledge into the same network. Our approach uses (1) a conditional variational autoencoder (CVAE) to generate accurate pseudo-examples (PEs) of prior tasks, (2) sweep-rehearsal requiring only a small number of PEs for each training iteration, (3) the appropriate weighing of PEs to ensure consolidation of new task knowledge with prior tasks, and (4) a novel network architecture we call MTL with Context inputs (MTLc) which combines the best of standard MTL and context-sensitive MTL (csMTL) architectures. Sequential learning of twenty classification tasks using a combination of MNIST and Fashion-MNIST datasets shows that our CVAE based approach to generating accurate PEs is promising and that MTLc performs better than either MTL or csMTL with minimal loss of task accuracy over the sequence of tasks
Kendall's tau with a blocking variable for time series data
No full textKendall's tau is a well known non-parametric statistic used for measuring the degree of dependency in bivariate data. This method has been well developed for data that is independent and identically distributed. However there is much less known about the case where data is not independently and identically distributed. The purpose of this thesis is to further expand the existing research of a weighted function of Kendall's tau for data with the addition of a third variable, c, the blocking variable. In this thesis we will build on the existing research for Kendall's tau with a blocking variable for the case when the bivariate data in the blocks is serially correlated time series data. As this new blocked function of Kendall's depends on the variance of individual block Kendall's tau estimates to compute the weighing function we will first focus on deriving a theoretical variance function for the standard Kendall's tau when the data is AR(1) stationary time series data. With the theoretical variance established we will use bootstrapping techniques to estimate this variance
allowing us to estimate the overall blocked Kendall's tau measure. To make inference on the blocked Kendall's tau estimate will use U-Statistics to develop a theorem on the asymptotic normal property of the blocked Kendall's tau fuction. With this result we will construct confidence intervals using the moving block bootstrap for the true measure of blocked dependency. To evaluate the effectiveness of the weighted funciton we will demonstrate these confidence intervals for both the weighted function and the unweighted function. Finally these methods will be implemented in a case study demonstration with real blocked time series data
The role of attachment style and emotional maladjustment in technology-based addictions
No full textThere is current interest in the association between adult attachment style and addiction, as well as a burgeoning interest in excessive technology use, constituting a behavioural addiction. Accordingly, the present study investigated the relation between behavioural measures of technology use and related self-report measures of addiction, whether attachment style was predictive of addiction to social media, texting, and video games, and whether emotional maladjustment indicators mediated the relation between attachment and addiction. Participants, n = 94, were undergraduate students who reported on their social media, texting, and cell phone game use over the past week using the Screen Time feature within their iPhones. They also provided an estimate of gaming across all platforms. Online questionnaires were used to measure adult attachment style, addiction to technology in three domains, and emotional maladjustment. The results demonstrated that the behavioural records of social media and cell phone gaming were significantly correlated with their respective addiction measures, whereas texting was not. The gaming estimate also significantly correlated to gaming addiction. It was also found that attachment anxiety and avoidance significantly predicted addiction to social media but no other form of addiction. Lastly, emotional maladjustment did not mediate the relation between attachment style and any technology-based addiction. The current study therefore informs interests in technology use and addictions, as well as adult attachment style and emotional maladjustment as related constructs