• A Case Study of Doctoral Research Assistantships: Access and Experiences of Full-Time and Part-Time Education Students

      Niemczyk, Ewelina; Department of Graduate and Undergraduate Studies in Education
      Graduate students’ development as researchers is a key objective in higher education. Research assistantships provide distinctive spaces where graduate students can be nurtured and shaped as novice researchers as they develop theoretical and methodological knowledge. However, few scholars have investigated graduate student research assistants’ experiences and the ways these experiences are influenced by institutional regulations, informal practices, and social relations. The purpose of this case-within-a-case study was to explore the research assistantship experiences of full-time and part-time doctoral students in Education at an Ontario university. I present separate subcases for full-time and part-time students, and an overarching case of research assistantships in one program at a specific period of time. The main question was how do institutional regulations, informal practices, and social relations influence full-time and part-time doctoral students’ access to and experiences within research assistantships. My objective was to draw from interviews and documents to acquire a thorough understanding of the organizational characteristics of research assistantships (i.e., structures of access, distribution, and coordination of participation) to explore the ways institutional regulations, informal practices, and social relations promote, prevent, or limit full-time and part-time students’ legitimate peripheral participation in research assistantships. Although I devoted particular attention to the ways students’ full-time and part-time status shaped their decisions, relationships, and experiences, I was conscious that other factors such as gender, age, and cultural background may have also influenced doctoral research assistant experiences.
    • Cell wall degrading enzymes and interaction between Trichoderma Aggressivum and Agaricus Bisporus

      Abubaker, Kamal Salem; Department of Biological Sciences (Brock University, 2010-10-26)
      Agaricus bisporus is the most commonly cultivated mushroom in North America and has a great economic value. Green mould is a serious disease of A. bisporus and causes major reductions in mushroom crop production. The causative agent of green mould disease in North America was identified as Trichoderma aggressivum f. aggressivum. Variations in the disease resistance have been shown in the different commercial mushroom strains. The purpose of this study is to continue investigations of the interactions between T. aggressivum and A. bisporus during the development of green mould disease. The main focus of the research was to study the roles of cell wall degrading enzymes in green mould disease resistance and pathogenesis. First, we tried to isolate and sequence the N-acetylglucosaminidase from A. bisporus to understand the defensive mechanism of mushroom against the disease. However, the lack of genomic and proteomic information of A. bisporus limited our efforts. Next, T. aggressivum cell wall degrading enzymes that are thought to attack Agaricus and mediate the disease development were examined. The three cell wall degrading enzymes genes, encoding endochitinase (ech42), glucanase (fJ-1,3 glucanase) and protease (prb 1), were isolated and sequenced from T. aggressivum f. aggressivum. The sequence data showed significant homology with the corresponding genes from other fungi including Trichoderma species. The transcription levels of the three T. aggressivum cell wall degrading enzymes were studied during the in vitro co-cultivation with A. bisporus using R T -qPCR. The transcription levels of the three genes were significantly upregulated compared to the solitary culture levels but were upregulated to a lesser extent in co-cultivation with a resistant strain of A. bisporus than with a sensitive strain. An Agrobacterium tumefaciens transformation system was developed for T. aggressivum and was used to transform three silencing plasmids to construct three new T. aggressivum phenotypes, each with a silenced cell wall degrading enzyme. The silencing efficiency was determined by RT-qPCR during the individual in vitro cocultivation of each of the new phenotypes with A. bisporus. The results showed that the expression of the three enzymes was significantly decreased during the in vitro cocultivation when compared with the wild type. The phenotypes were co-cultivated with A. bisporus on compost with monitoring the green mould disease progression. The data indicated that prbi and ech42 genes is more important in disease progression than the p- 1,3 glucanase gene. Finally, the present study emphasises the role of the three cell wall degrading enzymes in green mould disease infection and may provide a promising tool for disease management.
    • Cell-selective modulation of the neuromuscular system in Drosophila

      Ormerod, Kiel; Department of Biological Sciences
      The capacity for all living cells to sense and interact with their environment is a necessity for life. In highly evolved, eukaryotic species, like humans, signalling mechanisms are necessary to regulate the function and survival of all cells in the organism. Synchronizing systemic signalling systems at the cellular, organ and whole-organism level is a formidable task, and for most species requires a large number of signalling molecules and their receptors. One of the major types of signalling molecules used throughout the animal kingdom are modulatory substances (e.x. hormones and peptides). Modulators can act as chemical transmitters, facilitating communication at chemical synapses. There are hundreds of circulating modulators within the mammalian system, but the reason for so many remains a mystery. Recent work with the fruit fly, Drosophila melanogaster demonstrated the capacity for peptides to modulate synaptic transmission in a neuron-specific manner, suggesting that peptides are not simply redundant, but rather may have highly specific roles. Thus, the diversity of peptides may reflect cell-specific functions. The main objective of my doctoral thesis was to examine the extent to which neuromodulator substances and their receptors modulate synaptic transmission at a cell-specific level using D. melanogaster. Using three different modulatory substances, i) octopamine - a biogenic amine released from motor neuron terminals, ii) DPKQDFMRFa - a neuropeptide secreted into circulation, and iii) Proctolin - a pentapeptide released both from motor neuron terminals and into circulation, I was able to investigate not only the capacity of these various substances to work in a cell-selective manner, but also examine the different mechanisms of action and how modulatory substances work in concert to execute systemic functionality . The results support the idea that modulatory substances act in a circuit-selective manner in the central nervous system and in the periphery in order to coordinate and synchronize physiologically and behaviourally relevant outputs. The findings contribute as to why the nervous system encodes so many modulatory substances.
    • Cellular Mechanisms of Resveratrol's Interaction with Mitochondrial Reactive Oxygen Species Metabolism

      Robb, Ellen; Department of Biological Sciences (Brock University, 2013-05-14)
      Resveratrol, a polyphenol found naturally in red wines, has attracted great interest in both the scientific community and the general public for its reported ability to protect against many of the diseases facing Western society today. While the purported health effects of resveratrol are well characterized, details of the cellular mechanisms that give rise to these observations are unclear. Here, the mitochondrial antioxidant enzyme Mn superoxide dismutase (MnSOD) was identified as a proximal target of resveratrol in vitro and in vivo. MnSOD protein and activity levels increase significantly in cultured cells treated with resveratrol, and in the brain tissue of mice given resveratrol in a high fat diet. Preventing the increase in MnSOD levels eliminates two of resveratrol’s more interesting effects in the context of human health: inhibition of proliferative cell growth and cytoprotection. Thus, the induction of MnSOD is a critical step in the molecular mechanism of resveratrol. Mitochondrial morphology is a malleable property that is capable of impeding cell cycle progression and conferring resistance against stress induced cell death. Using confocal microscopy and a novel ‘cell free’ fusion assay it was determined that concurrent with changes in MnSOD protein levels, resveratrol treatment leads to a more fused mitochondrial reticulum. This observation may be important to resveratrol’s ability to slow proliferative cell growth and confer cytoprotection. Resveratrol's biological activities, including the ability to increase MnSOD levels, are strikingly similar to what is observed with estrogen treatment. Resveratrol fails to increase MnSOD levels, slow proliferative cell growth and confer cytoprotection in the presence of an estrogen receptor antagonist. Resveratrol's effects can be replicated with the specific estrogen receptor beta agonist diarylpropionitrile, and are absent in myoblasts lacking estrogen receptor beta. Four compounds that are structurally similar to resveratrol and seven phytoestrogens predicted to bind to estrogen receptor beta were screened for their effects on MnSOD, proliferative growth rates and stress resistance in cultured mammalian cells. Several of these compounds were able to mimic the effects of resveratrol on MnSOD levels, proliferative cell growth and stress resistance in vitro. Thus, I hypothesize that resveratrol interacts with estrogen receptor beta to induce the upregulation of MnSOD, which in turn affects cell cycle progression and stress resistance. These results have important implications for the understanding of RES’s biological activities and potential applications to human health.
    • Characterisation and optimisation of the flavour of health-promoting, plantderived bitterants in functional beverages.

      Gaudette, Nicole J.; Applied Health Sciences Program (Brock University, 2012-07-30)
      Flavour is a combination of taste, odour, and chemesthetic sensations. Close associations exist between these sensory modalities, and thus, the overall flavour of a food or beverage product can change when the intensity of one or more of these sensations is altered. Strategies to modify flavour are often utilized by the food industry, and are central to the engineering of new and reformulated products. For functional food and beverages, flavour modification is particularly important, as fortifying agents can elicit high levels of less than desirable sensations, such as bitterness and astringency. The application of various flavour modifying strategies can decrease the perceived intensity of these sensations, and in tum, improve the sensory profile of the product. This collection of studies describes the sensory characteristics of experimental functional beverages fortified with trans-resveratrol, (+)-catechin, and/or caffeine, and examines the impact of novel flavour modifying strategies on the perceived flavour of these beverages. In the first study, results demonstrate that the flavour profile of Cabemet Sauvignon wines fortified with 20 mglL and 200 mg/L of trans-resveratrol is not perceived as different compared to control wine (0 mglL). However, Riesling wine fortified with 200 mg/L is perceived as significantly higher in bitterness compared to 20 mglL and control. For some functional food formulations, alternative strategies for flavour modification are needed. Traditional methods, such as the addition of sucrose and sodium chloride, may decrease the perceived 'healthiness' of a product, and thus, may be sub-optimal. In a second study, high and low concentrations of five different bitter inhibiting compounds - 'bitter blockers' - (B-cyclodextrin, homoeridictyol sodium salt, carboxymethylcellulose - low viscosity, zinc sulfate, magnesium sulfate) were tested for their efficacy towards decreasing the bitterness of high and low concentrations of caffeine and (+)catechin - two health-relevant, plant-derived bitterants. B-cyclodextrin and homoeridictyol sodium salt were the most effective blockers at decreasing (+ )-catechin and caffeine, respectively. In addition to bitter blockers, additional flavour modifying strategies, either alone or in combination - may also be successful in functional food formulations. Both sucrose and rebaudioside A - a plant-derived sweetener - were effective at decreasing the bitterness of (+)catechin. When added to (+)-catechin along with B-cyc1odextrin, both sweeteners provided the most effective decrease in bitterness compared to binary, ternary, or quaternary mixtures of (+)catechin together with bitter blockers, sweeteners, andlor odourants. The perceived intensity of sensations elicited by sweeteners and odourants was not affected by the addition of bitter blockers, and thus, their impact within these complex matrices is minimal. In addition, withinmodal (taste-taste) compared to cross-modal (taste-odour) sensory interactions were more effective at decreasing the bitterness of (+ )-catechin. Overall, results from these studies demonstrate that certain novel, alternative flavour modifying approaches may be successful towards lowering the bitterness and astringency elicited by (+ )-catechin and caffeine in aqueous solutions.
    • Chemoenzymatic Formal Total Syntheses of Tetrodotoxin and an Approach to Daphenylline

      Baidilov, Daler; Department of Chemistry
      This thesis describes chemoenzymatic formal total syntheses of tetrodotoxin and a concise synthetic approach to daphenylline. Advanced intermediates for the syntheses of tetrodotoxin reported by the groups of Fukuyama, Alonso, and Sato were prepared. Key steps included toluene dioxygenase-mediated dihydroxylation of either iodobenzene or benzyl acetate and a [4+2] hetero-Diels-Alder cycloaddition/Kornblum–DeLaMare rearrangement sequence to construct a common enone intermediate. The resulting key enone was transformed into Fukuyama's intermediate in four steps, into Alonso's intermediate in six steps, and into Sato's intermediate in seven steps. Fukuyama’s route employed a highly stereoselective allyl cyanate-to-isocyanate rearrangement to install the nitrogen atom at C8a. This protocol was also successfully applied in designing a synthetic avenue to daphenylline. The ABC tricyclic skeleton of daphenylline was successfully constructed in just eight steps starting from readily available (S)-carvone.
    • Chemoenzymatic synthesis of amaryllidaceae alkaloids and their C-1 analogues : symmetry based approach to total synthesis of thebaine

      Collins, Jonathan A.; Department of Chemistry (Brock University, 2010-10-26)
      Described herein is the chemoenzymatic total synthesis of several Amaryllidaceae constituents and their unnatural C-I analogues. A new approach to pancratistatin and related compounds will be discussed along with the completed total synthesis of 7 -deoxypancratistatin and trans-dihydrolycoricidine. Evaluation of all new C-l analogues as cancer cell growth inhibitory agents is described. The enzymatic oxidation of dibromobenzenes by Escherichia coli 1M 109 (pDTG60 1) is presented along with conversion of their metabolites to (-)-conduritol E. Investigation into the steric and functional factors governing the enzymatic dihydroxylation of various benzoates by the same organism is also discussed. The synthetic utility of these metabolites is demonstrated through their conversion to pseudo-sugars, aminocyclitols, and complex bicyclic ring systems. The current work on the total synthesis of some morphine alkaloids is also presented. Highlighted will be the synthesis of several model systems related to the efficient total synthesis of thebaine.
    • Chemoenzymatic Total Synthesis of ent-Oxycodone

      Makarova, Mariia; Department of Chemistry
      This thesis describes the approach towards chemoenzymatic total synthesis of ent-dihydroisocodeine and chemoenzymatic total synthesis of ent-oxycodone as well as the development of a new method for the preparation of rearranged allylic isocyanates. The synthesis of ent-dihydroisocodeine started from phenethyl acetate and included a microbial oxidation of phenethyl acetate by E. coli JM109 (pDTG601A), a Mitsunobu reaction to the couple A- and C-rings, Heck cyclization to construct the E-ring and Henry reaction to introduce the nitrogen functionality as key steps. The construction of the B-ring proved to be challenging and neither radical cyclization nor attempts to perform photochemistry or nucleophilic opening of an epoxide gave any positive results. The chemoenzymatic total synthesis of ent-oxycodone was accomplished starting from phenethyl acetate in 23 steps. The tricyclic intermediate was furnished in the same manner as described above. The olefin to ketone conversion and a double Henry reaction allowed the construction of the B-ring. Unfortunately, it was established that the resulting hydroxyl group at C14 and amino group at C9 were of the undesired trans stereochemistry. To complete the morphine skeleton the transformation of the side chain at C13 to an N-methyl-p-toluenesufonamide via Mitsunobu reaction as well as the elimination of the amino group at C9 via formation of an N-oxide were performed. Subsequent radical cyclization of the side chain at the C9 position formed the last D-ring. The silyl ether deprotection followed by oxidation provided ent-oxycodone. The other approach to construct the D-ring was based on the formation of a lactone and the elimination of the amino group via an N-oxide. The nitrogen functionality was reinstalled using sodium azide and was accompanied by the introduction of the C10 hydroxyl group. Reduction of the azide and subsequent formation of the amide allowed access to the core skeleton of the target compound. The removal of the C10 hydroxyl group accomplished the synthesis. The last project involved the development of a new method for the preparation of rearranged allylic isocyanates from allylic alcohols using 1-cyano-4-dimethylaminopyridinium as the source of electrophilic cyanide. Experimental and spectral data are provided for all the compounds.
    • Chemoenzymatic Total Synthesis of Morphine alkaloids: Synthesis of Dihydrocodeine and Hydrocodone via a Double Claisen Strategy and ent-Hydromorphone via an Oxidative Dearomatization/intramolecular [4+2] Cycloaddition

      Varghese, Vimal; Department of Chemistry (Brock University, 2015-01-15)
      This thesis describes the chemoenzymatic synthesis of three morphine alkaloids. The total synthesis of dihydrocodeine and hydrocodone was accomplished starting from bromobenzene in 16 and 17 steps, respectively. The key steps included a microbial oxidation of bromobenzene by E. coli JM109 (pDTG601A), a Kazmaier-Claisen rearrangement of glycinate ester to generate C-9 and C-14 stereo centers, a Johnson-Claisen rearrangement to set the C-13 quaternary center, and a C-10/C-11 ring closure via a Friedel-Crafts reaction. In addition, the total synthesis of ent-hydromorphone starting from β-bromoethylbenzene in 12 steps is also described. The key reactions included the enzymatic dihydroxylation of β-bromoethylbenzene to the corresponding cis-cyclohexadienediol, a Mitsunobu reaction, and an oxidative dearomatization followed by an intramolecular [4+2] cycloaddition.
    • Children’s Developing Use and Understanding of Coercive Language: Applications in a Legal Setting

      Wylie, Breanne; Department of Psychology
      Within adult-child interactions, where children may be the target of coercion, it is important for children to understand and accurately describe their experiences. Coercive language is expressed using deontic modals, distinguishing between terms of obligation (i.e., implying compliance is required) and permission (i.e., implying compliance is optional). Children’s ability to understand and use coercive language is particularly relevant within applied legal settings where children may be required to testify about coercive tactics, and jurors may use this information to form perceptions about the case. Across three studies, my dissertation examined children’s understanding and use of coercive language, and the influence of using terms of obligation and permission on jurors’ perceptions of children’s reports. In Study 1, I examined 160 3- to 6-year-olds' understanding of the deontic modals tell and ask (referring to obligations and permissions) compared to their epistemic understanding of these terms (referring to knowledgeable and ignorant conversationalists), and the role of theory of mind in their understanding. In Study 2, I examined attorney and children’s use of coercive language within 64 transcripts of children’s testimony for cases involving alleged sexual abuse. In Study 3, I examined the influence of coercive language and maltreatment type on 160 adults’ perceptions of coercion and the child, as well as their judicial decision making. Overall, children’s understanding of the terms tell and ask emerged around 5 years of age, supported by their developing theory of mind. Additionally, children (as young as 6 years) and attorneys used terms of obligation and permission to describe coercion, and jurors were sensitive to these linguistic differences, perceiving children using terms of obligation as more coerced and the adult as more to blame. Of benefit, jurors’ decision making was not influenced by language, but rather focused on the nature of the abuse. Altogether these studies provide insight into children’s developing understanding of coercive language and suggest that even when used appropriately by 5 years of age, terms of permission minimize perceptions of coercion and adult blame. These findings demonstrate the need for educating adults about factors (e.g., coercive language) that may influence their perceptions of children’s disclosure.
    • The Cinematic Boogeyman: The Folkloric Roots of the Slasher Villain

      McGuiness, Kevin; Department of Philosophy
      This doctoral thesis complements earlier scholarship by Marina Warner concerning the Boogeyman as a figure representative of monstrosity and otherness by assessing these topics through an interdisciplinary lens. Employing a methodological approach that incorporates research from the fields of psychology, philosophy, and film studies, I analyse the Boogeyman within the context of the traditional fairytale and the modern horror film, and thereby reveal the key facets of this figure in the Western cultural imaginary. Specifically, I demonstrate that the villains of the contemporary slasher film (a subgenre of the horror film) are cinematic manifestations of the folkloric Boogeyman through a comparison of their physical and psychological attributes. Examining the archetypal properties of these characters, I argue that the traits that characterize the Boogeyman are the result of the fact that he is a composite of three archetypal forms: the collective Shadow, the Terrible Father, and the Death-Demon. I address three key questions: (1) what particular physical and psychological qualities are associated with the Boogeyman; (2) how the persona of the Boogeyman is constituted in the public consciousness; and (3) what moral, philosophical, and psychological role does he serve in Western culture. Over the course of this thesis, I demonstrate the fact that the Boogeyman represents the amalgamation of three archetypal components. Firstly, he embodies the role of the collective Shadow and functions to personify violent and anarchic characteristics that are repressed by the community and projected onto monstrous figures in the popular consciousness. Secondly, he is a manifestation of the negative attributes associated with the archetypal Father (referred to in literature as the “Terrible Father”) who punishes individuals that defy hegemonic values. Finally, he is a cultural embodiment of the Death-Demon, a conceptual figure that personifies anxieties related to death, and the degeneration of the body. This thesis provides a comparative analysis of a series of case studies that clearly illustrate the characteristics synonymous with the Boogeyman in the Western cultural imaginary. I begin with an examination of Bluebeard, a homicidal villain featured in Charles Perrault’s 1697 collection of fairytales titled Histoires ou contes du temps passé. In her seminal text No Go the Bogeyman, Warner posits Bluebeard as a clear example of the folkloric Boogeyman due to the fact that he is physically grotesque and morally repugnant. In Perrault’s story, Bluebeard is a villain who marries and then murders a series of women for disobeying him, and subsequently stores their bodies in his private chamber. Extrapolating the salient characteristics of Bluebeard as the folkloric Boogeyman, I assess these traits under an archetypal lens and demonstrate that Bluebeard/the folkloric Boogeyman is a manifestation of the collective Shadow, the Terrible Father, and the Death-Demon. After determining the archetypal properties of the folkloric Boogeyman, I highlight the presence of these same qualities in popular villains from the contemporary American slasher films of the 1970s and ’80s. Specifically, these characters include Michael Myers from Halloween (1978), Jason Voorhees of Friday the 13th (1980), and Freddy Krueger featured in A Nightmare on Elm Street (1984). Through my analysis of these terrifying figures, I situate them within a larger archetypal context of monstrosity and simultaneously establish their role as cinematic manifestations of the folkloric Boogeyman. This examination reveals the placement of the Boogeyman within the cultural imaginary as a violent disciplinarian who reinforces moral boundaries through sadistic acts of violence and paradoxically brings both chaos and harmony to the collective by preserving social borders. By extension, I demonstrate the link between the slasher film and the fairytale, both of which serve a didactic function, imparting hegemonic values to the public concerning sexual politics, social propriety, and moderation.
    • Cognitive Dissonance, Hypocrisy, and Reducing Toleration of Human Rights Violations

      Drolet, Caroline; Department of Psychology
      Despite documents such as the United Nations’ Universal Declaration of Human Rights, people still tolerate human rights violations. My dissertation examined possible methods for reducing this toleration. Specifically, I used “hypocrisy induction” to try and reduce toleration of rights violations and encourage pro-human rights responses. Hypocrisy induction—a procedure based on cognitive dissonance—involves having people recognize that their responses in a given situation are at odds with a strongly held attitude. In Study 1, I examined whether people who support human rights would reduce their toleration of a rights violation when confronted with their previous hypocritical toleration. Although participants who were confronted with their hypocrisy were more willing to act to promote human rights, they did not reduce their toleration of a violation, contrary to expectations. One reason for the lack of change in toleration could be that personal toleration of a human rights violation is not directly related to the occurrence of violations. Thus, for Studies 2 and 3, I extended the hypocrisy induction procedure to a case where an ingroup member’s hypocrisy directly resulted in a human rights violation. Specifically, I examined whether Canadians would alter their own toleration of a violation in response to a Canadian official who permitted a human rights violation. Results from both studies indicated that the group-level procedure was effective at encouraging pro-human rights responses, but not at reducing toleration of a violation. Moreover, results from Study 3 indicated that the effect of the group-level procedure was the result of directly-experienced, not vicarious, discomfort. I refer to the dissonance associated with the former type of discomfort as “group-level” dissonance. Although hypocrisy induction was not useful for reducing the toleration of human rights violations, my results suggest that both the group- and individual-level procedures can be used to encourage other pro-human rights responses.
    • Competing demands for a complex system : photosystem II repair, photoprotection and quantum yield

      Veerman, John; Department of Biological Sciences (Brock University, 2012-04-04)
      Photosynthesis in general is a key biological process on Earth and Photo system II (PSII) is an important component of this process. PSII is the only enzyme capable of oxidizing water and is largely responsible for the primordial build-up and present maintenance of the oxygen in the atmosphere. This thesis endeavoured to understand the link between structure and function in PSII with special focus on primary photochemistry, repair/photodamage and spectral characteristics. The deletion of the PsbU subunit ofPSII in cyanobacteria caused a decoupling of the Phycobilisomes (PBS) from PSII, likely as a result of increased rates of PSII photodamage with the PBS decoupling acting as a measure to protect PSII from further damage. Isolated fractions of spinach thylakoid membranes were utilized to characterize the heterogeneity present in the various compartments of the thylakoid membrane. It was found that the pooled PSIILHCII pigment populations were connected in the grana stack and there was also a progressive decrease in the reaction rates of primary photochemistry and antennae size of PSII as the sample origin moved from grana to stroma. The results were consistent with PSII complexes becoming damaged in the grana and being sent to the stroma for repair. The dramatic quenching of variable fluorescence and overall fluorescent yield of PSII in desiccated lichens was also studied in order to investigate the mechanism by which the quenching operated. It was determined that the source of the quenching was a novel long wavelength emitting external quencher. Point mutations to amino acids acting as ligands to chromophores of interest in PSII were utilized in cyanobacteria to determine the role of specific chromophores in energy transfer and primary photochemistry. These results indicated that the Hl14 ligated chlorophyll acts as the 'trap' chlorophyll in CP47 at low temperature and that the Q130E mutation imparts considerable changes to PSII electron transfer kinetics, essentially protecting the complex via increased non-radiative charge Photosynthesis in general is a key biological process on Earth and Photo system II (PSII) is an important component of this process. PSII is the only enzyme capable of oxidizing water and is largely responsible for the primordial build-up and present maintenance of the oxygen in the atmosphere. This thesis endeavoured to understand the link between structure and function in PSII with special focus on primary photochemistry, repair/photodamage and spectral characteristics. The deletion of the PsbU subunit ofPSII in cyanobacteria caused a decoupling of the Phycobilisomes (PBS) from PSII, likely as a result of increased rates of PSII photodamage with the PBS decoupling acting as a measure to protect PSII from further damage. Isolated fractions of spinach thylakoid membranes were utilized to characterize the heterogeneity present in the various compartments of the thylakoid membrane. It was found that the pooled PSIILHCII pigment populations were connected in the grana stack and there was also a progressive decrease in the reaction rates of primary photochemistry and antennae size of PSII as the sample origin moved from grana to stroma. The results were consistent with PSII complexes becoming damaged in the grana and being sent to the stroma for repair. The dramatic quenching of variable fluorescence and overall fluorescent yield of PSII in desiccated lichens was also studied in order to investigate the mechanism by which the quenching operated. It was determined that the source of the quenching was a novel long wavelength emitting external quencher. Point mutations to amino acids acting as ligands to chromophores of interest in PSII were utilized in cyanobacteria to determine the role of specific chromophores in energy transfer and primary photochemistry. These results indicated that the Hl14 ligated chlorophyll acts as the 'trap' chlorophyll in CP47 at low temperature and that the Q130E mutation imparts considerable changes to PSII electron transfer kinetics, essentially protecting the complex via increased non-radiative charge.
    • A comprehensive examination of adolescent gambling

      Chalmers, Heather.; Department of Psychology (Brock University, 2004-05-28)
      The purposes of this study were: a) to examine the prevalence and consequences associated with adolescent gambling, b) to examine the factors which influence adolescent gambling,. c) to detennine what factors discriminate among four groups of gamblers (no-risk/non-gamblers, low-risk gamblers, at-risk gamblers, and high-risk/problematic gamblers), and d) to examine the relation of gambling to nine other risk behaviours (i.e., alcohol use, smoking, marijuana use, hard drug use, sexual activity, minor delinquency, major delinquency, direct aggression, and indirect aggression). Adolescents (N = 3,767) from 25 secondary schools completed a twohour survey that assessed involvement in risk be~aviours as well as potential predictors from a wide range of contexts (school, neighbourhood, family, peer, and intrapersonal). The majority of adolescents reported gambling, although the frequency of gambling participation was low. The strongest predictors/discriminators of gambling involvement were gender, unstructured activities, structured activities, and risk attitudes/perceptions. In addition, the examination of the co-occurrence of gambling with other risk behaviours revealed that for high-risk/problem gamblers, the top three most frequent co-occurring high-risk behaviours were direct aggression, minor delinquency and alcohol. This study was the first to examine the continuum of gambling involvement (i.e., non-gambling to high risk/problematic gambling) using a comprehensive set ofpotential predictors with a large sample of secondary school students. The findings of this study support past research and theories (e.g., Theory of Triadic Influence) which suggest the importance ofproximal variables in predicting risk behaviors. The next step, however, will be to examine the direct and indirect 1 effects of the ultimate (e.g., temperament), distal (e.g., parental relationship), and proximal variables (e.g., risk attitudes/perceptions) on gambling involvement in a longitudinal study.
    • Conceptions of Quality and Approaches to Quality Assurance in Ontario’s Universities

      Goff, Lori-Ann; Department of Graduate and Undergraduate Studies in Education (Brock University, 2015-02-13)
      Many international, political, and economic influences led to increased demands for development of new quality assurance systems for universities. Like many policies and processes that aim to assure quality, Ontario’s Quality Assurance Framework (QAF) did not define quality. This study sought to explore conceptions of quality and approaches to quality assurance used within Ontario’s universities. A document analysis of the QAF’s rationale and structure suggested that quality was conceived primarily as fitness for purpose, while suggested indicators represented an exceptional conception of quality. Ontario universities perpetuated such confusion by adopting the framework without customizing it to their institutional conceptions of quality. Drawing upon phenomenographic traditions, a qualitative investigation was conducted to better understand various conceptions of quality held by university administrators and to appreciate ways in which they implemented the QAF. Three main approaches to quality assurance were identified: (a) Defending Quality, characterized by conceptions of quality as exceptional, which focuses on administrative accountability and uses a hands-off strategy to defend traditional notions of quality inputs and resources; (b) Demonstrating Quality, characterized by conceptions of quality as fitness for purpose and value for money, which focuses on accountability to students and uses centralized engaged strategies to demonstrate how programs meet current priorities and intended outcomes; and (c) Enhancing Quality, characterized by conceptions of quality as transformation, which focuses on reflection and learning experience and uses engaged strategies to find new ways of improving learning and teaching. The development of a campus culture that values the institution’s function in student learning and quality teaching would benefit from Enhancing Quality approaches to quality assurance. This would require holistic consideration of the beliefs held by members of the institution, a clear articulation of the institution’s conceptions of quality, and a critical analysis of how these conceptions align with institutional practices and policies.
    • The Conceptualization and Exploration of Place Allegiance: Towards a Unified Model of Person-Place Relationships within Outdoor Recreation

      Howard, Ryan; Applied Health Sciences Program
      The academic study of place has been generally defined by two distinct and highly refined discourses within outdoor recreation research: place attachment and sense of place. Place attachment generally describes the intensity of the place relationship, whereas sense of place approaches place from a more holistic and intimate orientation. This study bridges these two methodological and theoretical separate areas of place research together by re-conceptualizing the way in which place relationships are viewed within outdoor recreation research. The Psychological Continuum Model is used to extend the language of place attachment to incorporate more of the philosophy of sense of place while attending to the empirical strength and utility of place attachment. This extension results in the term place allegiance being coined to depict the strong and profound relationships outdoor recreationists build with their places of outdoor recreation. Using a concurrent mixed methods research design, this study explored place allegiance via an online survey (n = 437) and thirteen in-depth qualitative interviews with outdoor recreationists. Results indicate that place allegiance can be measured through a multi-dimensional model of place allegiance that incorporates behaviours, importance, resistance, knowledge and symbolic value. In addition, place allegiance was found to be related to an individual's influence on life course and his/her willingness to exhibit preservation and protection tendencies. Place allegiance plays an important role in acknowledging the importance of authentic place relationships in an effort to confront placelessness. Wilderness recreation is an important avenue for outdoor recreationists to build strong place relationships.
    • Conservation laws of magnetohydrodynamics and their symmetry transformation properties

      Pshenitsin, Dmitry; Department of Physics
      All kinematic conservation laws along with their symmetry transformation properties are derived for the system of magnetohydrodynamic equations governing incompressible viscous plasmas (or any other conducting fluid) in which the dynamic and magnetic viscosities are constant. Reductions of this system under translation symmetries, axial rotation symmetries, and helical symmetries are considered. For each reduced system, all kinematic conservation laws and point symmetries are obtained. The results yields several new conservation laws which are expected to be relevant for physical applications of magnetohydrodynamics.
    • Considerations for the Development and Optimization of Wine made from Partially Dehydrated Grapes in Ontario, Canada

      Kelly, Jennifer; Centre for Biotechnology
      The appassimento process for making wine can mitigate climatic challenges associated with cool climate winemaking, as fruit is dried post-harvest, reducing vintage-to-vintage variation due to varying fruit quality. Resultant wines fermented from dried grapes are high in ethanol and described as rich and intensely flavoured. One of the quality challenges facing wine made from partially dehydrated grapes is elevated levels of undesirable oxidation compounds, such as ethyl acetate, acetic acid and acetaldehyde. In this study we aim to characterize wines made from a local yeast isolate, Saccharomyces bayanus CN1, which demonstrates limited osmotolerance and may have application to this wine style, as it is a lower producer of such compounds. Wines made with the yeast of interest were compared to wines made with the accepted commercial yeast, Saccharomyces cerevisiae, EC1118. Fermentations were established over two vintages at one and three target starting sugar concentrations and a control, respectively. Wines were chemically (enzymatic) and sensorially analyzed. Wines (year two) were subject to volatile organic compound (VOC) and volatile fatty acid (VFA) measurements via Gas Chromatography-Mass Spectrometry. Another consideration for the development of this wine style is the inclusion of Botrytis cinerea, a pathogenic fungus that commonly develops during grape drying, and may impart favourable sensorial characteristics. Grapes were dried to 28.0°Brix and were fermented with EC1118 at 0 and 10% B. cinerea infection. A consumer preference test (n=153) that measured liking of wines (CN1 and 0% and10% B. cinerea infection) was conducted. Results indicate that CN1’s upper limit for fermentation to dryness is 27.5°Brix. All CN1 wines had significantly lower concentrations (p<0.05) of oxidation compounds than the commercial yeast, and oppositely, higher glycerol levels, along with comparable ethanol concentration to EC1118 wines. Significant differences in the concentrations of VOCs and VFAs, such as 2-phenylethanol and hexanoic acid were observed both within °Brix treatments and amongst yeast strains. Sensorially, the wines differed in intensity for a number of attributes. The consumer study revealed no preference between wines vinified with the different yeast strains. This work will contribute to the optimization of this wine style in cool climate winemaking regions and beyond.
    • Creating Space, or Just Juggling? Exploring the Adoption of Innovation in Community Sport

      Jurbala, Paul; Jurbala, Paul; Applied Health Sciences Program
      Previous research into community sport organization (CSO) has focused heavily on capacity and resource deficits and the ways in which CSOs manage under these constraints. This study explores mechanisms influencing CSOs as they adopt and implement an innovation: Long-Term Athlete Development (LTAD). A critical realist, extensive-intensive design spanning 36 months was used. The first, extensive phase of the study examines the contextual mechanisms influencing the approach of CSOs to adopting the LTAD innovation. Resource dependence and institutional perspectives are integrated to describe the forces acting on CSOs, how these manifest in structures, and how the structures channel the agency of CSO leaders as they work to balance resources and deliver programs. A contextual model of CSO operation under conflicting institutional logics is presented. The second, intensive phase examines the question of how CSOs plan, learn, and consolidate learning into structure as they integrate an innovation. Here, an engaged case study methodology was used to focus on the efforts of a single CSO over a one-year period as it worked to implement LTAD while managing multiple resource constraints. A learning cycle was used to explore processes of embedded agency resulting in structural change. CSOs are conceptualized as juggling resource constraints while balancing conflicting institutional logics: the communitarian logic promoted by resource controllers such as municipalities and Provincial Sport Organizations, and the individualist logic followed by CSO members. The results of the study demonstrate how CSOs compete for resources while balancing these institutional pressures and how when possible, CSOs manipulate institutional factors to gain legitimacy and contingent access to resources. In this competitive environment, LTAD represents a new institutional pressure. CSOs determine whether to adopt LTAD in part based on whether resource controllers signal that compliance will bring legitimacy and enhance resource access. When resource- controlling organizations introduce standards like LTAD intended to improve CSO program quality, the unintended result can be inter-CSO competition for legitimacy that can lead to the systematic privileging of large CSOs at the expense of smaller ones, driving professionalization and potentially increasing costs of sport participation.
    • Creativity and the schizophrenia spectrum unveiled : the similarities and the differences

      Michalica, Kerri; Department of Psychology (Brock University, 2010-10-27)
      This study examined the commonalities and the differences between creativity and the schizophrenia spectrum. The variables measured as potential commonalities and differences were creativity, schizotypy, cognitive inhibition, spatial ability, balancing skills, positive and negative presence, absorption, mystical experiences, childhood abuse, and neuroticism. Three community groups were recruited, consisting of 31 artists, 10 people with schizophrenia, and 31 comparisons matched for gender and age with the artists. A larger student group consisting of 102 students was also recruited in order to examine the correlations among the same variables within a larger, more normative, group. The largest commonality between the artist and the schizophrenic groups, who represented the extreme end of the schizophrenia spectrum, was the propensity to mystical experiences. The greatest differences between the artist and the schizophrenic groups were that the artists were higher in creativity, performed better on spatial abilities, had better balance, had more positive states of presence, and were lower in neuroticism than the schizophrenic group. In the student group, creativity was correlated with spatial ability, positive presence, absorption, and mystical experiences. In addition, creativity was significantly related to two facets of schizotypy, unusual experiences and impulsive nonconformity. In other words, students high in certain facets of schizotypy, who may share certain characteristics with those who have schizophrenia, are higher in creativity, but people who are on the extreme end of the schizophrenia spectrum, who have been diagnosed with schizophrenia, are not. The differences between the artist and schizophrenic groups on spatial ability, balance, sense of presence, and neuroticism may help to determine whether mystical experiences help to integrate creative work or destabilize and disorganize the sense of self. It may be that mystical experiences can be used more positively by the creative individuals than people with schizophrenia, in that artists and people high in creativity were higher in positive traits such as positive presence and lower on negative variables such as neuroticism, and introvertive anhedonia.