Newly Added Theses

Permanent URI for this collectionhttps://hdl.handle.net/10464/1147

Students enrolled in graduate programs at Brock University will be required to submit an electronic copy of their thesis to this repository as part of graduation requirements. Students are required to submit their thesis directly. Instructions on how to do this can be found online

Browse

Now showing 1 - 20 of 89

Open Access
Diversity of Tomato Brown Rugose Fruit Virus in Canadian Greenhouses
(Brock University) Fougere, Gregory Charles; Griffiths, Jonathan S; Despres, Charles; Department of Biological Sciences
Tomato brown rugose fruit virus (ToBRFV) has been a serious threat to greenhouse tomato production worldwide since its emergence in 2014 in Israel and Jordan. A member of the Tobamovirus genus, ToBRFV’s ability to break the longstanding Tm-22 resistance gene and ease of mechanical transmission has allowed the virus to spread rapidly through greenhouses worldwide. Little is known regarding the extent and genomic diversity of ToBRFV in Canada, despite the major impacts of this virus on greenhouse tomato production. 15 new Canadian ToBRFV genomic sequences have been determined, combined with 5 additional Canadian ToBRFV isolates retrieved from GenBank, and 5 consensus sequences assembled from a Canadian metagenomics wastewater monitoring study. The 25 Canadian sequences were combined with 332 international ToBRFV isolates to create a global phylogeny. Most Canadian isolates grouped together with other North American isolates but, several isolates branched separately, suggesting multiple introductions of ToBRFV to Canadian greenhouse systems. Canadian isolates sequenced in 2019 and 2024 originating from three different greenhouses grouped together, suggesting transmission of ToBRFV between greenhouses in Canada, showing that biosecurity of greenhouses is vital for the control of ToBRFV. Focused analysis on individual viral ORFs show the p126 and movement protein (MP) are the most variable regions of the genome. Novel mutations unique to Canadian isolates of ToBRFV were identified in both the p126 and MP. In the p126, 5 mutations were found in an area previously shown to directly interact with the TM-1 protein. Three of these mutations were unique to Canadian ToBRFV isolates and may be novel Tm-1 breaking mutations. In the MP, four novel mutations were identified that do not appear to be associated with Tm-22 and are potentially involved in breaking resistance mediated by an unknown resistance gene. Additionally, 7 isolates from greenhouse 2 had mutations in both the p126 and the MP, suggesting the virus has acquired potential resistance breaking mutations for multiple resistance genes. Until more robust resistance is identified, ToBRFV will continue to be a major threat to greenhouse tomato production in Canada.
Open Access
The Process of Photography, The US Combat Veteran, and Somaesthetics: A Multi-case Study
(Brock University) Trzecak, Terry; Jaipal Jamani, Kamini; Department of Sociology
War fundamentally transforms the essence of existence. Whether directly or indirectly, war irreversibly alters the historical, present, and prospective futures of all humans affecting every facet of human life. Individuals who have not served, the adage, ‘war is hell,’ provides minimal understanding of the realities encountered by combatants. ‘War is hell’ transforms into ‘life is hell,’ illustrating the challenges that combat veterans encounter after military service. American combat veterans who served in the Wars on Terror in Afghanistan and/or Iraq (2001-2021), regardless of the duration since their military service encounter significant challenges in reintegrating into civilian life, affecting their physical, mental, and economic well-being. The maxim, 'living in the present,' is frequently seen as an effective remedy for rumination in numerous veterans' programs. Still, how do you do it? Many endure solitude, limiting their ability to obtain varied therapeutic interventions, particularly those centered on mindfulness, embodiment, and self-regulation. This multi-case study of six US combat veterans sought to examine the usefulness of engaging in mindfulness through a series of photographic activities involving the deliberate act of photographing. This inquiry asked: What are the lived experiences and sensory responses of American combat veterans who utilize the process of photography as a mindfulness-based somatic strategy to facilitate their journey towards well-being? Using an inductive cross-case analysis process, three themes emerged. First, the shift towards well-being in civilian life encompassed three factors, including (a) participants were challenged in reconciling their military and civilian identities; (b) military training/experiences affected self-identity and health both positively and negatively; and (c) an ill-informed public perception negatively impacted the transitioning veteran. Secondly, participants reported achieving present moment awareness through mindfulness by engaging in the process of photography which involved perceiving physical sensations while deliberately exploring new perspectives via the camera. Moreover, the process of photography enabled participants to be more attentive to novel elements of their surroundings by freeing the mind from rumination. Finally, the process of photography was viewed by these participants as a practical tool for enhancing self-reflection via mindfulness and creative engagement, thereby serving as an appropriate support for promoting well-being.
Open Access
Exploring the Structural, Magnetic, Optical, and Catalytic Properties of High-Spin Materials
(Brock University) Bakhshi, Hamed; Pilkington, Melanie; Department of Chemistry
This thesis explores the design, synthesis, and characterization of lanthanide-based coordination frameworks (MOFs) and heterometallic 3d/4f complexes, with a focus on tunable magnetic behavior, photophysical properties, and catalytic performance. Four complementary research directions were pursued, each addressing key challenges in molecular magnetism, luminescence and sustainable catalysis. The first project examines a family of isomorphous Dy(III), Gd(III), and Tb(III)-MOFs constructed from 2',5'-bis(methoxymethyl)-[1,1':4',1''-terphenyl]-4,4'' dicarboxylic acid (H2L2.1). Systematic post-synthetic solvent exchange led to tunable structural perturbations that profoundly affected the magnetic relaxation dynamics and photophysical behavior of the Dy-MOF. Alternating current (ac) magnetic studies of the Dy-MOF series revealed distinct relaxation pathways linked to subtle crystallographic changes. A second ligand, 2',5' bis(ethoxymethyl)-[1,1':4',1''-terphenyl]-4,4''-dicarboxylic acid (H2L2.2), demonstrated how minimal chemical modifications to the linker can afford new MOFs with conserved coordination geometries and consistent magnetic and luminescent properties across the lanthanide series. These results underscore the sensitivity of magnetic relaxation and energy transfer processes to both the framework structure and local symmetry. In the second project, three novel, isostructural Dy-, Gd- and Tb-MOFs were synthesized from 4,4′-(1,2,4,5-tetrazine-3,6-diyl)dibenzoic acid (H₂TZDC). ac magnetic studies revealed the MOFs exhibit complex temperature-dependent slow magnetic relaxation, attributed to combined quantum tunneling (QTM), Orbach, and Raman mechanisms. Notably, the Gd-based system displays rare frequency-dependent relaxation, rationalized by a small axial anisotropy in the crystal field. Photoluminescence studies on this series of MOFs reveal inefficient ligand-to-metal energy transfer, attributed to mismatched electronic energies. In the third study a series of tetranuclear {Cu₄Ln₄} clusters assembled from the rac-mpzmH ligand are reported. Magnetostructural studies reveal that weak Cu–Ln antiferromagnetic coupling, strong Cu–Cu ferromagnetic interactions, and variations in the coordination geometries collectively govern the magnetic behaviour. Field-induced slow relaxation was observed in the {Cu4Dy4} cluster, while the Tb and Er analogues exhibited active QTM, effectively suppressing relaxation over the energy barrier even in the presence of an external magnetic field. The photoluminescence was largely quenched by the Cu(II) centers, although trace Ln-centered emission was observed in the {Cu4Tb4} cluster. These results highlight the interplay between nuclearity, bridging geometry, and electronic structure in determining the magnetic and optical properties. Project 4 focuses on heterometallic 3d/4f complexes of the form [TM₂Ln(TX-TACN)]⁺ (TM(II) = Cu and Zn; Ln(III) = Gd, Dy, Tb, Eu and Ho); and TX TACNH3 = N,N′,N″-tris(3,5-dimethyl-2-hydroxybenzyl)-1,4,7-triazacyclononane) as catalysts for the cycloaddition of CO₂ with epoxides. X-ray diffraction studies revealed that all the complexes comprise of a linear TM–Ln–TM motif with a subtle variation in the coordination geometry dependent upon the 3d ion. Catalytic studies showed that the Zn(II)-based complexes significantly outperform their Cu(II) counterparts, achieving high turnover numbers and frequencies for propylene oxide conversion. Selectivity studies using cyclohexene oxide demonstrate stereochemical control and unique reactivity pathways. The catalytic performance varies with the 4f metal and counterion, demonstrating the modularity and adaptability of these systems for green chemistry applications.
Open Access
Understanding the effects of isoDGR in neurodegeneration
(Brock University) Ridhi Patel; Newman Siu Kwan Sze; Applied Health Sciences Program
With the global population aging, the prevalence of chronic diseases such as Alzheimer’s disease and vascular dementia is increasing, emphasizing the urgent need to understand the underlying molecular mechanisms. Degenerative protein modifications (DPMs), including isoAsp-Gly-Arg (isoDGR) motif which is formed via spontaneous deamidation of NGR sequence, are increasingly recognized as contributors to age-related tissue dysfunction. Traditionally considered untreatable molecular damage, isoDGR has been shown to mimic integrin-binding motifs and trigger inflammatory responses, yet its role in neurodegeneration remains poorly understood. In this study, we investigated the effects of isoDGR-motif on key brain cell types, including brain endothelial cells (bEnd3) and neurons (N2A) using in vitro models. IsoDGR exposure induced cellular senescence, characterized by increased β-galactosidase activity, elevated p16 and p53 expression, nuclear translocation of p27, and reduced Lamin B1 levels. We also observed enhanced oxidative stress, particularly mitochondrial ROS, and impaired cell proliferation. Importantly, isoDGR disrupted endothelial monolayer permeability by altering tight junction (ZO-1) and adherens junction (VE-Cadherin) protein expression, increasing permeability and impairing cell migration. ICAM-1 and VCAM-1 expression was also increased in bEnd.3 cells. Together, these findings indicate that isoDGR promotes neuroinflammatory and neurovascular dysfunction, the hallmarks of neurodegenerative disease. This thesis establishes isoDGR as a potential pathophysiological relevant driver of cellular dysfunction in the aging brain. Targeting DPMs such as isoDGR may represent a novel therapeutic approach to mitigate neurodegeneration and extend health-span.
Open Access
The Relations Among Attentional Difficulties, Perfectionism, and Procrastination in Young Children
(Brock University) Maguire, Madeline; Mahy, Caitlin; Department of Psychology
Adults with attentional difficulties and adults who display certain aspects of perfectionism both show higher levels of procrastination (Niermann & Scheres, 2014; Sirois et al., 2017). Determining whether these relations are present early in the lifespan is crucial, as this would indicate that children with these tendencies are possibly at risk of experiencing the adverse outcomes of chronic procrastination (e.g., Beutel et al., 2016; Sirois et al., 2003). Therefore, the present study investigated the relations among attentional difficulties, perfectionism, and procrastination in preschool children. We also examined age as a potential moderator of these associations to determine whether they show stability across the preschool period. Finally, we explored whether self-control or emotion regulation mediate these relations, as theories suggest that deficits in these abilities drive adult procrastination (Sirois & Pychyl, 2013; Steel, 2007). Parents of 3- to 6-year-olds (N = 274; Mage = 33.6, SD = 5.8; 168 mothers) completed online questionnaires measuring their child’s procrastination tendencies (Fuke et al., 2023), attentional difficulties (Conners, 2009; McGoey et al., 2007), self-control (Gioia et al., 2003), and emotion regulation (Conners, 2009). Parents also completed a new questionnaire developed for the current study in which they reported on their child’s perfectionism. We found that while attentional difficulties and procrastination were positively correlated with each other, perfectionism and procrastination were negatively correlated with each other. Neither of these associations was moderated by children’s age, suggesting that both relations are relatively stable throughout the preschool years. In addition, the association between attentional difficulties and procrastination was partially mediated by self-control, but neither self-control nor emotion regulation mediated the association between perfectionism and procrastination. Since the current study was cross-sectional, future research should seek to examine these mediational pathways longitudinally. However, our findings provide evidence that children with attentional difficulties may benefit from intervention to reduce their procrastination, whereas children with perfectionistic tendencies may not demonstrate increased procrastination until later in development.
Open Access
Recognizing Whiteness: An Autoethnographic Examination of Whiteness in My Life
(Brock University) Beres, Jacqueline L.; McGinn, Michelle; Department of Graduate and Undergraduate Studies in Education
The purpose of this research was to examine whiteness not merely as an individual attribute but as an ideological and structural system that organizes everyday life and grants privilege to those perceived as white. Using a blend of critical and evocative autoethnography, I wrote stories about my life experiences. I drew on critical whiteness studies and critical race theory to expose how whiteness operates as a normative force in institutions, social interactions, and academic knowledge production. The analysis I undertook helped me understand how I was welcomed in public spaces like libraries whereas racialized individuals in similar settings have been left questioning whether they were being excluded. My analysis also illuminated how my whiteness insulated me from developing a rich understanding of Black culture, particularly the cultural significance of Black hair. This work prompted me to question the extent to which my conception of “safety” while travelling was, in fact, a coded interpretation of white superiority. In hopes of appealing to a general audience beyond academia, I adopted a non-traditional dissertation format. I used footnotes to deviate from the expected in-text citation system and create an additional, co-occurring text, which I offer as one (albeit very minor) form of action aimed at disrupting white dominance within academia. My research adds to the collection of work, and particularly critical whiteness studies, completed in response to the calls from racialized authors, scholars, and activists for white people to engage in anti-racist action. By weaving personal narrative with systemic critique, my aim is to contribute to dismantling white supremacy and promote sustained, justice-oriented action among white readers committed to anti-racism. Given that white people have a critical responsibility to identify whiteness and eradicate the oppression that we collectively perpetuate, I hope my findings can help white readers as they progress on their personal racial justice journeys. For racialized readers, I hope my study offers additional insight into how white people recognize—and often, fail to recognize—whiteness, along with how we attempt to dismantle whiteness and fight for racial equity.
Open Access
On the Optical Properties of the Misfit Layer Compound (PbSe)1+δ(NbSe2)n
(Brock University) Respicio, Paul Carlo; Reedyk, Maureen; Department of Physics
Misfit layer compounds (MLCs) are layered materials that consist of two different sublattices with a mismatch in at least one of their lattice parameters. This incommensurate mismatch along with charge transfer between the constituent sublattices gives rise to interesting properties and can potentially be tuned for practical applications. These systems can be understood using the framework of rigid band model and the changes in band filling depending on the extent of interlayer charge transfer. This thesis presents the optical properties of (PbSe)1+δ(NbSe2)n and their evolution as the number of NbSe2 layers, n, are varied. NbSe2 is a known transition metal dichalcogenide superconductor and PbSe is a semiconductor with a rocksalt structure. NbSe2 and n=1-3 samples were synthesized via chemical vapour transport and characterized via X-ray diffraction, energy dispersive X-ray spectroscopy, and atomic force microscopy. Further characterization from resistivity and magnetization measurements showed a decrease in the superconducting transition temperature, Tc, with decreasing n. Reflectivity measurements were analyzed using the Drude-Lorentz model and reveal a shift in the plasma frequency to lower energies as n decreases along with the broadening of their interband transitions when compared to pure NbSe2. This behaviour is consistent with increased band filling due to charge transfer from PbSe to NbSe2. Optical conductivity functions were obtained using Kramers-Kronig analysis confirm decreased conductivity for the MLCs and follow a similar pattern found in the resistivity measurements. Finally, frequency-dependent scattering rate and effective mass were obtained from the extended Drude model. Results show a region of purely Drude response in the scattering rate for the MLCs and a trend of decreasing mass enhancement with decreasing n at low wavenumber.
Open Access
Determining the Roles of the Aldehyde Dehydrogenase Enzymes 5 and 6 during Icewine and Table Wine Fermentation in a Commercial Wine Yeast Using CRISPR-Cas9.
(Brock University) Ott-Peon, Nadine; Inglis, Debra; Centre for Biotechnology
Canada is known for Icewine which is fermented from grapes naturally frozen on the vine. Grapes are harvested below –8°C and pressed while frozen, trapping ice crystals inside the berries and releasing juice highly concentrated in sugars and acids. The high sugar juice environment (40°Brix) causes hyperosmotic stress for yeast, resulting in water loss, triggering glycerol production to act as an internal osmolyte to draw water back into the yeast cell, resulting in an NAD+ imbalance. Icewine has significantly higher acetic acid versus table wine, where acetic acid production may be used to reduce NAD(P)+ to NAD(P)H via NAD(P)+-dependent aldehyde dehydrogenase proteins (Aldp). Previous research linked the NAD+ redox imbalance during Icewine fermentation with ALD gene expression patterns indicating a role of Ald3p encoded by ALD3 in elevating the acetic acid whereas in table wine, ALD6 expression dominated. In the overall research program from our laboratory, the goal is to remove all five of the ALD genes, individually and in combination, from a commercial yeast genome using CRISPR-Cas9 gene editing. The objective of this project is to remove three (ALD6, ALD5, and ALD4) of the five ALD genes individually from the genome of a commercial wine yeast K1 V1116 using CRISPR-Cas9 gene editing to assess the roles of the aldehyde dehydrogenase enzymes in acetic acid production in both Icewine and table wine using these commercial yeast deletion strains. All copies of ALD6 and ALD5 were successfully knocked out of K1-V1116. The ald6Δ yeast had a significant impact on the acetic acid production with an 86% decrease in acetic acid production during Icewine fermentation and an 85% decrease during table wine fermentation in comparison to the wild-type control yeast. The ald5Δ had a significant but minimal impact on acetic acid production during table wine fermentation and no impact on acetic acid during Icewine fermentation. Under table wine conditions, ald5Δ had a 16% decrease in acetic acid production. One allele of the ALD4 gene was successfully knocked out of K1-V1116, creating a heterozygous ALD4 mutant. This heterozygous mutant was not evaluated in fermentations.
Open Access
Theoretical Investigation of the Electronic Structure in the Reaction Center of Acaryochloris marina
(Brock University) Etemadi Some Olyayi Katayoun; Dr Divya Kaur Matta; Centre for Biotechnology
This thesis explores the electronic structure of photosystem I (PSI) in far-red lightutilizing organism Acaryochloris marina through density functional theory (DFT), with a particular focus on the spin density distribution around the P740 reaction center and its surrounding residues. While the final hyperfine couplings show excellent agreement with experimental values, they reveal a nearly symmetric spin density between the A and B branches, rather than the anticipated localization on the B branch. Various computational parameters, including the choice of functional, optimization method, and model size, were systematically examined to determine their influence on the final results. Among the tested functionals, TPssh produced the most pronounced asymmetry while keeping the hyperfine coupling values close to the experiment. CHARMM-based optimizations yielded lower RMSD values, indicating greater structural accuracy compared to quantum-based optimizations. A detailed residue analysis identified specific amino acids such as Trp660 and Leu623 that play a significant role in modulating spin density, particularly due to their proximity to the reaction center. Interestingly, some residues like Phe653 showed minimal influence despite their size, suggesting that spatial positioning is more critical than steric bulk alone. Additionally, hydrogen bonding networks involving selected residues may further influence electronic asymmetry by stabilizing charge distribution pathways. These computational insights provide a deeper understanding of how local residue environments affect PSI function and may help explain the evolutionary adaptations seen in organisms like Acaryochloris marina, which perform photosynthesis efficiently under far-red light. The study concludes by recommending future QM/MM calculations with expanded QM regions to better capture the protein environment and resolve discrepancies between computational models and experimental data.
Open Access
Physiological and behavioural responses to temperature and humidity in fossorial amphibians
(Brock University) Danilo Giacometti; Glenn Tattersall; Department of Biological Sciences
Amphibians have been the focus of research investigating physiological and behavioural responses to temperature and humidity for over two centuries. However, fossorial (i.e., underground-dwelling) amphibians remain comparatively understudied despite the unique environmental pressures that they experience. The overarching goal of this thesis was to understand how temperature and humidity affected the physiology and behaviour of fossorial amphibians. By combining phylogenetic methods and laboratory experiments, my chapters address the topics of energetics, hydroregulation, thermoregulation, and overwintering emergence. First, I tested the prevailing hypothesis that fossorial amphibians should have reduced metabolic rates compared to non-fossorial ones. My results did not support this hypothesis, highlighting that a reduction in amphibian metabolism would be evolutionary unlikely given the limited energetic benefit. Next, I assessed the effect of seasonal acclimatisation (spring versus autumn) on the thermal sensitivity of metabolism and water loss in Ambystoma maculatum. My findings suggested that acute changes in temperature affected energy and water budgets. However, acclimatory changes in temperature affected metabolism but not water loss. I then examined how temperature (17°C versus 22°C) influenced behavioural hydroregulation in A. maculatum. I found that salamanders defended a constant vapour pressure deficit between temperatures, which was achieved by targeting higher relative humidity at 22°C than at 17°C. This suggests that salamanders can detect their rates of evaporative water loss, and employ behaviours to limit increased evaporative demand at warmer temperatures. I also evaluated how behavioural thermoregulation differed between seasons (active versus overwintering), and found that A. maculatum engaged in active behavioural thermoregulation despite the prediction that fossorial ectotherms should show little thermoregulatory motivation. Lastly, I assessed how extrinsic (temperature and negative geotaxis) and intrinsic (migration restlessness) factors influenced overwintering emergence in A. maculatum. My results suggested that migration restlessness and negative geotaxis collectively influenced overwintering emergence, shedding light on how fossorial amphibians may navigate complex underground environments. Together, my chapters underscore the intricate coupling between physiology and behaviour in mediating how fossorial amphibians respond toshort- and long-term environmental variation.
Open Access
Testing Northeastern North American Native and Introduced Plants as Cover Crops in an Organic Vineyard
(Brock University) Zgurzynski, Kasia; Vasseur, Liette; Department of Biological Sciences
Cover crops have potential to provide ecosystem services including nitrogen fixation, erosion control, water retention and infiltration, buffering climate variability, and beneficial insect attraction. The objective of my thesis was to examine the potential performance of diverse cover crop species in an organic vineyard. The first component of this study aimed at testing northeastern North American native cover crop species, including Dalea purpurea, Rudbeckia hirta, Glycyrrhiza lepidota, Asclepias tuberosa, Echinacea purpurea, and Symphyotrichum ericoides. In the greenhouse, plants grown in monoculture were compared to those grown in polyculture with all the other species. The performance measurements were based on emergence, flowering, dry biomass, fresh biomass, plant moisture content, root:shoot ratio, and relative interaction index. R. hirta had a significantly higher dry shoot and root weight when grown in polyculture, as opposed to monoculture. D. purpurea also had significantly higher dry root weight in polyculture rather than in monoculture. S. ericoides and G. lepidota had significantly higher dry shoot and root weight in monoculture than in a polyculture. A. tuberosa had the largest root biomass in monoculture, while E. purpurea had the largest root biomass in the individual treatment. The second component aimed to determine the efficacy of two cover crop species (Lobularia maritima and Trifolium incarnatum) in vineyard field conditions. The plants were seeded under the vine rows, and plots were sampled along those seeded rows for each species. One vegetation survey was completed, and two insect surveys. Vegetation was measured as percent cover in the sample plots, and insects were collected on yellow sticky traps. L. maritima abundance was positively correlated with spontaneous plant species abundance, and T. incarnatum abundance was negatively correlated with spontaneous plant species abundance. The presence of the L. maritima was weakly associated with an increase in parasitoids, while T. incarnatum was weakly associated with predatory insects. Where there were more parasitoids, there were fewer leafhoppers. My results suggest a potential of these various species to provide important ecosystem services such as pest control in organic vineyards. Understanding the interactions among cover crop species, their influence on vines and the entire ecosystem requires further studies.
Open Access
Examining the Underlying Mechanisms and Potential Outcomes of Stress Bragging
(Brock University) Han Yi; Faculty of Business Programs
This study investigates the mechanisms behind stress bragging in workplaces and its impact on individuals and organizations, focusing on impression management (IM) tactics as a mediator. It posits that individuals use stress bragging to achieve desirable workplace outcomes through IM tactics. Despite its prevalence, the interplay between stress bragging and workplace outcomes remains underexplored. This research addresses this gap by examining the dualistic impacts of stress bragging—beneficial outcomes for individuals (e.g., promotability) and detrimental effects for organizations (e.g., social loafing). Additionally, it explores the moderating role of competitive work environments (CWE). The study collected temporally segregated data from employees (n = 355) across diverse industries in the USA and Canada. The findings revealed significant and positive direct effects between stress bragging and negative workplace outcomes, as well as between stress bragging and impression management (IM) tactics. Furthermore, the results provided evidence for the mediating role of IM tactics as the underlying mechanism linking stress bragging to various workplace outcomes, though the proposed moderating effects of competitive work environment (CWE) were not supported. This study is among the first to explore how stress bragging influences workplace outcomes through various IM tactics in an organizational context, offering theoretical and practical insights for navigating and managing such behaviors in the workplace.
Open Access
The Development of Future Thinking in Childhood
(Brock University) Kamber, Ege; Mahy, Caitlin; Department of Psychology
Humans’ ability to represent future possibilities, known as future-oriented cognition, encompasses several skills, including saving, prospective memory, episodic future thinking, planning, and delay of gratification. Developmental research has primarily focused on preschool and school-aged children and examined the development of future-oriented cognition in relation to cognitive and language abilities. The current studies contribute to the literature in three ways by examining (a) the early emergence of future-oriented cognition in toddlerhood (Study 1), (b) how children’s home environment relates to their future-oriented cognition (Study 2), and (c) whether three candidate cognitive mechanisms (i.e., constructive episodic simulation, scene construction, and self-projection) can explain school-aged children’s episodic future thinking (Study 3). Study 1 (N = 205 parents of 2- to 3-year-olds) used parent-report questionnaires to show that 2- and 3-year-olds could engage in future thinking skills in their everyday lives (i.e., prospective memory, episodic future thinking, planning, saving, and delay of gratification). Children’s episodic memory and use of time metaphors in daily talk further explained individual differences in children’s future thinking skills. Study 2 (N = 325 parents of 2- to 6-year-olds) also used parent-report measures and found that parents’ future-oriented cognition – but not family socioeconomic status – was related to children’s future-oriented cognition, even after accounting for children’s age, cognitive abilities, and behavioural factors. Study 3 (N = 150 8- to 10-year-olds) used behavioural measures to assess children’s episodic future thinking and other abilities that may rely on the same cognitive mechanisms as episodic future thinking, including episodic memory, episodic thinking for present events, imagination, perspective-taking, and spatial navigation. Structural equation modeling showed that children’s episodic future thinking, episodic memory, episodic thinking for current events, imagination, and spatial navigation shared significant variance, aligning with the constructive episodic simulation and scene construction accounts. However, the data did not support the self-projection account because perspective-taking was unrelated to the other abilities. Together, these studies shed light on the developmental trajectory of future-oriented cognition from the age of 2 to 10, identify its correlates and illuminate potential cognitive mechanisms of episodic future thinking.
Open Access
Exploring the Process of Organizational Change within the Sport Industry: A Stakeholder Perspective
(Brock University) McFall, Chandler; Kerwin, Shannon; Thompson, Ashley; Applied Health Sciences Program
Stakeholders in sport organizations often hold unique and diverse perspectives on organizational change, yet literature has been shown to evaluate these perspectives from a static point in time. With change more recently being found to be a dynamic, unpredictable process as opposed to being predictable in nature (Dawson, 2019) this research sought to understand how stakeholders responded to a large-scale organizational change over time. Thus, this study examines the implementation of Long-Term Player Development (LTPD) within a community sport organization, with a particular evaluation of how these stakeholders' responses shifted over time. To investigate this, a constructivist approach was adopted, drawing on semi-structured interviews with key stakeholders involved at various levels of the organization. A total of 12 interviews were conducted, capturing a range of perspectives across paid staff, coaches, and parents. This open-ended method enabled a deeper exploration of the underlying beliefs, emotions, and contextual factors that shaped stakeholder engagement with the change process. Findings were interpreted through a lens of stakeholder theory (Mahon & Waddock, 1992; Freeman, 1984), revealing how individuals navigated personal meaning and emotion during change, and further how their positioning in the organization influenced their responses. Stakeholder reactions were categorized through an updated spectrum of the stakeholder responses to change created by Welty Peachey & Bruening (2011, 2012) (e.g., acceptance, ambivalence, resistance), ranging from proactive engagement to active opposition. These responses were marked by positive or negative shifts in response as new information and experiences emerged, largely dependent on personal goals, values, and expectations. Overall, these reactions were not static but found to be dynamic, shaped by both personal values and organizational actions. This research contributes to sport management literature by offering a deeper understanding of stakeholder engagement in times of change, and highlights the importance of communication relating to stakeholder needs. The findings further demonstrate the value of capturing the unique dimensions of change and stakeholders commonly found within community sport organizations and youth sport.
Open Access
Mental Toughness in Sport: Empirical Distinctiveness and Relationships with Risk-taking and Pain Experiences in Athletes.
(Brock University) Blacker, Mishka; Sullivan, Philip; Applied Health Sciences Program
Mental Toughness (MT) is a term typically used to describe the determination and focus of athletes who often thrive or produce clutch performances in pressurized situations (Bédard Thom et al., 2021; Gucciardi, 2017; Jones et al., 2002; Hardy et al., 2014). Despite widespread interest in this concept (Gucciardi et al., 2020), research has tended to focus on the performance enhancing and thriving aspects of MT while only limited research has attended to potentially maladaptive aspects and outcomes (Cowden et al., 2021; Kerr & Stirling, 2017). The purpose of this dissertation was to 1) contribute to the conceptual clarity of MT in athletes, 2) increase knowledge of the relationship between MT and risk-taking by looking at specific types of risk-taking behaviours in sport, and 3) examine and explore relationships between MT, physical endurance, and pain experiences in athletes. The results of this dissertation supported the distinctiveness of MT via the Mental Toughness Index (Gucciardi et al., 2015) in competitive athletes (study 1). Study 2 suggested that when MT is assessed via the MTI, it is not predictive of risk-taking attitudes or behaviours that have the potential to be maladaptive in sport (i.e., competing with pain or injury). Lastly, the results of study 3 built on the equivocal findings reported in previous work (Crust & Clough, 2005; Jones, 2020) evidencing non-significant relationships among MT, physical endurance, pain coping, and pain intensity, suggesting that that these relationships are nuanced and conditional. Future research is recommended to focus on the potential of MT’s additivity with other concepts (e.g., Grit), investigating MT’s association with different kinds of risk-taking (i.e., positive, negative) behaviours over time, and examining MT’s relationship with pain by incorporating self-referenced goals and/or different pain manipulations (e.g., cold pain tolerance, DOMS pain intensity; Whitton et al., 2021), as well as a general recommendation for experimental and longitudinal designs when possible. 2025
Open Access
Advancing detection, genomics, and secretome analysis of oomycete pathogens Phytophthora capsici and Phytopythium vexans to explore mechanisms of pathogenesis and biocontrol solutions
(Brock University) Villanueva Oscar; Castle Alan; Ellouz Oualid; Department of Biological Sciences
Soilborne oomycete pathogens pose persistent challenges to vegetable production systems, particularly in Ontario, Canada, where Phytophthora capsici and the recently reported Phytopythium vexans have emerged as significant threats. Understanding the molecular mechanisms underlying their pathogenicity is critical for developing informed, site-specific disease management strategies. This thesis integrates comparative genomics, effector biology, and molecular diagnostics to enhance our understanding of their pathogenicity and support effective disease management. The first component of this work focuses on P. capsici, where whole-genome sequencing of two Canadian isolates (55330 and 55898) revealed compact genomes yet retained a broad array of RxLR and CRN effectors. Comparative analyses with reference strains LT263 and LT1534 v11.0 uncovered both conserved and unique effectors, suggesting that local adaptation may be shaping pathogenic potential in response to regional crop pressures. Building on this, the second component shifts to P. vexans, a novel strain recently reported in Ontario from apple tree soil. The SS21 P. vexans strain genome was sequenced and compared with the only two openly available strains HF1(China), and (CBS 119.80) (Iran). The genomic analysis reveals similar genome between the Canadian strain SS21 and the reference genomes, additionally SS21 displayed a reduce CAZymes, RxLR and CRN effectors, suggesting a niche adaptation to a specific Canadian agro-ecosystem. The final component of this thesis focuses on the development of an amplitude-based multiplex droplet digital PCR (ddPCR) assay. Designed for simultaneous quantification of P. capsici, Trichoderma asperellum, and Trichoderma gamsii in soil, this assay was validated in field trials and offers high sensitivity and specificity. The assay displayed a high sensitivity with a limit of detection of 1 pg/µL DNA. The use of multiplex ddPCR offers practical solution for monitoring pathogen and biocontrol populations in complex soil environments.
Open Access
Advancing detection, genomics, and secretome analysis of oomycete pathogens Phytophthora capsici and Phytopythium vexans to explore mechanisms of pathogenesis and biocontrol solutions
(Brock University) Villanueva Oscar; Castle Alan; Ellouz Oualid; Department of Biological Sciences
Soilborne oomycete pathogens pose persistent challenges to vegetable production systems, particularly in Ontario, Canada, where Phytophthora capsici and the recently reported Phytopythium vexans have emerged as significant threats. Understanding the molecular mechanisms underlying their pathogenicity is critical for developing informed, site-specific disease management strategies. This thesis integrates comparative genomics, effector biology, and molecular diagnostics to enhance our understanding of their pathogenicity and support effective disease management. The first component of this work focuses on P. capsici, where whole-genome sequencing of two Canadian isolates (55330 and 55898) revealed compact genomes yet retained a broad array of RxLR and CRN effectors. Comparative analyses with reference strains LT263 and LT1534 v11.0 uncovered both conserved and unique effectors, suggesting that local adaptation may be shaping pathogenic potential in response to regional crop pressures. Building on this, the second component shifts to P. vexans, a novel strain recently reported in Ontario from apple tree soil. The SS21 P. vexans strain genome was sequenced and compared with the only two openly available strains HF1(China), and (CBS 119.80) (Iran). The genomic analysis reveals similar genome between the Canadian strain SS21 and the reference genomes, additionally SS21 displayed a reduce CAZymes, RxLR and CRN effectors, suggesting a niche adaptation to a specific Canadian agro-ecosystem. The final component of this thesis focuses on the development of an amplitude-based multiplex droplet digital PCR (ddPCR) assay. Designed for simultaneous quantification of P. capsici, Trichoderma asperellum, and Trichoderma gamsii in soil, this assay was validated in field trials and offers high sensitivity and specificity. The assay displayed a high sensitivity with a limit of detection of 1 pg/µL DNA. The use of multiplex ddPCR offers practical solution for monitoring pathogen and biocontrol populations in complex soil environments.
Open Access
NEW ROUTES IN BIOCATALYSIS: EXPLORING THE IMPACT OF GRAFTING SILICONES ONTO PROTEINS/ENZYMES
(Brock University) Alizadeh, Najibeh; Dr. Paul M. Zelisko; Department of Chemistry
One of the cornerstones of our research is the use of biocatalysis to mitigate the negative impact of chemical processes on the environment. The majority of natural enzymes are highly efficient and can increase the rate of chemical transformations. However, the industrial application of enzymes is often restricted by several limiting factors such as poor operational or long-term stability, especially during exposure to elevated temperatures, organic solvents, and pH extremes. The chemical modification of enzymes using covalent conjugation is a very common stabilization strategy as it imparts stability and protects the enzyme from denaturation. A number of studies have determined that hydrophobic surfaces can have a very positive impact on the reactivity of various enzymes, particularly lipases. The impact of silicones on proteins, mostly through physical/noncovalent interactions has attracted considerable attention recently. Given our research team’s ongoing work in the area of silicone-proteins/enzymes interactions it was of interest to explore the impact of covalently conjugated silicone polymers on proteins. Herein, a library of hydride-functionalized silicones of differing molecular masses was prepared using the living anionic ring opening polymerization of hexamethylcyclotrisiloxane (D3) to yield poly(dimethylsiloxane) (PDMS) polymers with narrow dispersities (Ð). These polymers were subsequently activated with hydrophilic functional groups including disuccinimidyl carbonate (DSCa) and norbornene dicarboxylate anhydride (NDA) prior to conjugation with proteins/enzymes. Human serum albumin (HSA) was selected as a model protein to study the PDMS/protein chemical interactions prior to the functionalization of enzymes. HSA’s well-documented spectroscopic behaviour as either a native protein or denatured species made it an ideal model to investigate the impact of covalently bonded silicones on proteins. After completion of model protein studies, trypsin and Candida antarctica lipase B (CALB) were modified chemically with functionalized PDMS polymers. The covalent bonding of PDMS polymer chains onto protein/enzyme was studied through matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry. The solubility of the protein/enzyme conjugates were examined in various organic solvents including tetrahydrofuran (THF), chloroform, dichloromethane (DCM), dimethylformamide (DMF), and toluene and confirmed by UV-Vis spectroscopy. The impact of silicones on the protein/enzyme structure was investigated by infrared (IR), circular dichroism (CD), and fluorescence spectroscopy. Thermal behaviour of the protein/enzymes before and after modification with PDMS polymers were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Catalytic function, thermal stability, and the accessibility of active sites of the enzymes of interest after conjugation to the functionalized siloxanes were studied through standard activity assays. This work demonstrates that not only can siloxanes be successfully coupled to proteins, but the bioconjugation also enhances the solubility and activity of enzymes in organic solvents.
Open Access
Perceptions of Ghanaian Women Regarding Breast Cancer Screening Behavior
(Brock University) Ashorm Faustina; Crawford Joanne; Applied Health Sciences Program
Background: Breast cancer among women is currently the most diagnosed cancer globally, with an estimated 2.3 million cases recorded in 2020. In Ghana, breast cancer constitutes 31.8% of all cancers diagnosed in women in 2020 with an incidence rate of 15 to 35 per 100,000. Research into factors that influence engagement of Ghanaian women in breast cancer screening is limited and the existing literature has produced conflicting results. This research aimed to enhance understanding of Ghanaian women’s knowledge, beliefs and attitudes regarding breast cancer. This study explored Ghanaian women’s perceptions of breast cancer screening behaviour and provided insights to how breast cancer is perceived and approached within this context. By investigating these perceptions, the study sought to uncover the factors influencing Ghanaian women’s participation in early detection and breast screening. Methods: In this study, I employed a qualitative research design based on Interpretive Description by Thorne (2016), focusing on women in the mixed rural community of Apra, Ghana. Data were gathered through semi-structured interviews with 14 local women, with an interview guide informed by constructs from the Health Belief Model (HBM) and the Theory of Planned Behavior. Key constructs, such as perceived barriers, perceived severity, perceived susceptibility, perceived benefits and subjective norms, were explored. Using reflexive thematic analysis, as outlined by Braun and Clarke (2022), the analysis provided in-depth exploration of participants perceptions, highlighting key themes related to their health beliefs and behaviors. Findings: The study revealed that Ghanaian women’s perceptions of breast cancer screening are shaped by cultural beliefs, stigma, and limited knowledge. Key themes included the view of the breast as sacred, leading to reluctance in discussing or undergoing screenings, and the fear of social judgment, with some seeing breast cancer as a moral or spiritual failure. Participants had limited knowledge of breast cancer symptoms but were open to receiving information from healthcare professionals. Additionally, faith in divine protection influenced some women’s reluctance to seek medical care. These findings highlight the need for culturally sensitive health education to promote early detection. Significance and Conclusion: This study contributes to the academic discourse on breast cancer awareness by providing evidence on the perceptions and screening behaviors of Ghanaian women. It highlights the influence of cultural beliefs, social norms, and limited knowledge on early detection practices. The insights gained can inform the development of community-engaged, culturally sensitive health education programs and may guide policies, aimed at improving breast cancer screening uptake and access to breast health services in mixed rural Ghanaian communities.
Open Access
Consumer Desires in the Niagara Wine Industry: A Geodemographic Analysis of Customers at a Niagara Winery
(Brock University) Murdoch, Sara; Ripmeester, Michael; Department of Geography
The wine tourism industry is a global industry. Here, the focus will be primarily on winery visitors in the Niagara Region. More specifically, I explore what motivates them to visit wineries and what they hope to experience during their visits. Given significant competition, wineries must cater their expectations to attract visitors to their cellar doors. The purpose of this thesis is to determine whether geodemographic factors (type of community, municipality, general location) in combination with the demographic (age, gender, education, income) factors have an impact on what motivates people to visit wineries and what they expect once they arrive. More precisely, this thesis aims to answer the research question: “Do visitor origin and associated demographics make a difference in motivation to visit a winery and visitor experience expectations?” While doing so, I examine the two sub-themes. First, and as noted above, I seek to explore whether there is there a correlation between expectations for winery experiences and residence of trip origin and other demographic characteristics. Second, I ask “What winery features are visitors hoping to experience?” Using the mailing lists of one small, recently rebranded boutique winery in Jordan Station, Ontario I distributed web-based surveys to collect data on October 3 and 20, 2023. The survey was distributed through two mailing lists (the general mailing list and wine club list to 1568 individuals. A total of 133 individuals responded. Following the data collection process, I used qualitative and quantitative data analysis including coding, cross tabulations, Chi-Square tests, and location analysis though ESRI Community Analyst to explore the data. The analysis did not provide conclusive answers that suggests that location and geodemographic characteristics were significant in determining motivations to visit the winery. The results did, however, allow me to reach the conclusion that visitors are attracted to the experience and social aspects of wineries over the wine itself. In sum, the data collected can provide valuable information, both practical and academic contributions, on how to cater experiences to a larger audience.

Browse

Recent Submissions