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Exploiting Epigenetic Variation for Crop Improvement in the Emerging Oilseed Crop Camelina Sativa
No full textIn the emerging oilseed crop Camelina sativa, breeding efforts have been focused on optimizing seed size and oil quality traits to improve its productivity for Canadian agriculture. Considering that epigenetic mechanisms, such as DNA methylation, undergo dynamic changes throughout seed development, we hypothesized that it may play an important regulatory role in seed traits. We created a drd1 mutant that showed a global reduction in DNA methylation predominantly within transposable elements in the upstream region of genes. Loss of DNA methylation in the drd1 seed was found to have a relatively small effect on the expression of genes. We did, however, detect transcriptional changes in 69 hypomethylated genes, of which two candidate genes, FRK1 and ACP2, are predicted to be involved in seed development. This study showcases the potential influence of epigenetics on gene expression and offers insights on the functional relevance of DNA methylation in seed development
Holocaust Memory, Aesthetics and the Dictatorships of the Southern Cone of Latin America: Interconnecting Memories and Traumas
No full textMy dissertation examines how Holocaust tropes, figures, and icons have travelled across cultural landscapes and been adopted by Southern Cone writers and artists to reflect on the atrocities perpetrated during the dictatorships in Uruguay (1973-1985), Argentina (1976-1983), and Chile (1973-1990). Specifically, I focus on the literary trope of “filling in the void,” the visual trope of the “presence of absence” and silhouette figure, and the icon of Anne Frank, as I analyze selected writings of Uruguayan Jewish writer Mauricio Rosencof, the memory-activist intervention created by Argentinian artists Rodolfo Aguerreberry, Julio Flores, and Guillermo Kexel, and selected poetry and children’s literature of Chilean Jewish writer Marjorie Agosín, respectively. Through my analysis, I highlight the transformations of these Holocaust tropes, figures, and icons, and center on the multidirectional memories that a decentered reading of these texts and visual pieces offers relating to both of these traumatic histories. As I focus on these dialogical encounters of memory, I underscore how diverse mediums (literary fiction, poetry, photography, visual art, protest art, and textile art) provide access to different memories and interconnections between the Holocaust and the Southern Cone dictatorships. These case studies also highlight different personal, collective, cultural, and postmemories of both atrocities, and emphasize different victims, including prisoners, detained-disappeared persons, gendered experiences, and those of witnesses (both direct and indirect ones). My research expands the fields of memory studies, Holocaust studies, and Latin American Jewish and memory studies. It examines Holocaust memory from a decentered perspective while highlighting the significance of Latin American literary and visual representations of trauma. My work is guided by comparative and transcultural readings of the selected corpus and follows the theoretical framework of Michael Rothberg’s multidirectional memory and Astrid Erll’s transcultural memory while incorporating Latin American and Southern Cone theorizations of memory such as those of Fernando Ortiz, Diana Taylor and Macarena Gómez-Barris. My interdisciplinary methodological and transcultural positionality brings into focus complementary Latin American perspectives alongside traditional (i.e., European / North American) interpretations and underscores transcultural intersections that otherwise would not be foregrounded in these fields. My research also prompts readers to consider the problematics of multidirectional memory
Developmental Cognitive Neuroimaging And Socioeconomic Status: Determining Whether Research In Affluent Western Countries Reveal The Right Approach Globally
Get PDFThis meta-analysis of peer-reviewed neuroimaging findings assessed the magnitude of effect sizes (ES) of the influences of low socioeconomic status (SES) on children’s neurodevelopmental outcomes to evaluate the strengths of SES-related effects, to determine whether these were consistently detrimental and to quantify instances of implicit deficit attribution (IDA) in the literature. The literature search yielded 130 studies from 1988 to 2022; more than 85% of which were conducted in Western, high-income nations. Bayesian models revealed ESs were heterogeneous across countries, continental regions and national income levels. Bayesian and standard hypothesis testing indicated high- and low-SES groups showed similar behavioral performances in neuroimaging tasks. A bibliometric analysis showed a significant proportion of the literature attributed neurocognitive deficits to low-SES groups. To reach United Nations Sustainable Development Goals, policies and interventions should consider regional, structural, or environmental factors beyond the individual, critically probing IDAs
Situating Relationships in the Context of Power, Privilege and Vulnerability: Social Workers Experiences Working with Clients who do not meet the Check Boxes of Marginality
No full textDrawing on relational theories, specifically relationship-based, critical, and anti-oppressive social work theories, this thesis explored how social workers in a northern Ontario community experience direct practice relationships with people who occupy multiple privileged identities, who may be enacting their power, and may not be following ascribed roles and rules of client engagement. Interested in listening to social workers direct practice experiences, and situating and contextualizing these experiences in the stories that they shared, four (4) social workers working in North Bay, Ontario participated in two narrative interviews. Data was analyzed through narrative thematic and structural approaches to understand how and in what ways positionality, identity, power, and privilege impacts work with cisgender, straight, white, male clients. Critical and illuminating practices were shared which highlighted how power, privilege and vulnerability were woven into understanding, building and maintaining relationships with clients. Findings of this study offer questions for future practice and education
Well-Being of Recent Migrants: The Role of Place-Based and Social Connections
No full textPlace-based and social connections provide a sense of belonging and can act as protective factors against stress. Following migration, disruption to these connections can be particularly challenging when facing migration-related stressors in a new place. As a result, many migrants desire to form new connections, though they often also want to maintain their original connections. It may be beneficial for migrants to find continuity between their former and current place-based and social connections, however, it is unclear how differences between these connections are reconciled. To better understand how migrants bring together former and current connections (or not), a series of mixed methods studies was conducted with recent migrants in Canada to assess the impact of place-based and social connections and how negotiating incompatibilities between former and new connections can strengthen a sense of belonging to new surroundings. Study 1 (N=67), a photovoice study, revealed that positive places provided reminders of home, upheld aspects of pre-migration identity, helped make new connections, and allowed reflection on migration experiences. Although negative places primarily represented challenges, participants often saw the value in these challenges in shaping their migration journey. Essentially, experience in positive and negative places both played a role in shaping place-based and social connections. Study 2 (N=117), a survey study, determined that place identity and social identity mediated the relationships between acculturation strategies with migrant well-being. The relationship between integration with social identity promoted well-being whereas the relationships between assimilation and marginalization with place/social identity appeared to diminish well-being. Study 3 (N=74) involved a controlled, multi-meeting intervention study that targeted the development of either place-based or social connections to support post-migration well-being. Qualitative analyses suggested that finding balance, reappropriating former connections, making situational adaptations, and relying on connections helped migrants to negotiate incompatibilities between the former and current place. In addition, providing knowledge and skills to manage place-based and social connections appeared to improve post-migration outlook. These studies underscore the potential role of place-based and social connections in resiliency during migration transition and may provide a better understanding of the variability in the incidence of well-being concerns among recent migrants
Deciphering the Role of ARK5 and hnRNP A1 in Regulating the Osmotic Stress.
No full textOsmotic stress is a significant stressor influencing cellular responses, including the subcellular localization of the heterogeneous nuclear ribonucleoprotein (hnRNP A1), a nucleocytoplasmic-shuttling RNA-binding protein that plays a vital role in nucleic acid metabolism and gene expression regulation. The function of hnRNP A1 is determined partly by its specific location within the cell. Although some work has been done to elucidate the signalling pathways that regulate the cellular localization of hnRNP A1, the consequences and mechanisms of the altered hnRNP A1 localization still need to be fully understood. We have previously conducted an unbiased RNAi-based kinome-wide screen to identify kinases that regulate hnRNP A1 localization during osmotic stress. In this work we characterized one of the hits from this screen, AMPK-related protein kinase 5 (ARK5), as the kinase controlling hnRNP A1 subcellular localization in response to hypertonic stress. ARK5 directly phosphorylates hnRNP A1 on serine residues within the F-peptide region. In addition, the silencing of ARK5 increases the expression of the anti-apoptotic protein Bcl-xL and consequently delays caspase activation during hypertonic stress. Although ARK5 regulates cell survival through hnRNP A1, the downstream osmotic stress response genes are not known. Studies show osmotic stress activates different signaling pathways and induces expression of distinct genes. For example, hypertonic stress induces expression of the aldose reductase (AR), fibronectin 1 (FN1), and vimentin (VIM) in cells. Interestingly, ARK5 is upregulated in diabetics nephropathy (DN), which is triggered by hypertonic stress in the nephron during the early stages of DN. Therefore, we hypothesized that ARK5 might be the upstream regulatory molecule that controls the expression of the downstream osmotic stress-response genes through hnRNP A1. Our mRNA abundance and mRNA translation data suggest that the osmotic stress-response genes behave differently in different cell-types. Our data indicate that VIM, and partially FN1, are increased during the osmotic stress response; however, this regulation is not controlled by ARK5
Relative Pose Determination of a Non-Cooperative Spacecraft using Thermal Imagery
No full textAccurate and reliable pose determination of a non-cooperative spacecraft is a critical requirement for applications of on-orbit servicing, orbital debris removal, and in-space assembly missions. Recent advances in deep learning and the increasing availability of open-source datasets have enabled researchers to advance the work in this field by experimenting with deep learning algorithms. To date, all open-source datasets use imagery in the visible spectrum; however, visible imagery has a known limitation where the models perform poorly in harsh lighting conditions. This research introduces a novel lab-generated ML dataset for spacecraft pose estimation using thermal imagery rather than visible as a potential solution to the problem. Additionally, a design for a "light-weight" Convolutional Neural Network architecture is introduced, which uses 50% fewer parameters than state-of-the-art architectures in the field and demonstrates performance comparable to a typical architecture on the novel dataset
To Go or Not to Go: Exploring Gen Z's Attitudes toward Museum Visiting
No full textThis research explores why Generation Z visits or avoids museums. Surveys and interviews with Gen Z undergraduates examined their motivations, using education, social cohesion, and entertainment as key lenses. Results showed Gen Z values museums for education and entertainment but were less convinced about their role in fostering social cohesion. Interviews highlighted why participants felt museums aren't attracting enough young visitors, and suggestions for improvement were provided. The study concludes with recommendations for museums to better engage Gen Z and enhance their appeal to this demographic
User Privacy in OAuth-Based Single Sign-On Systems
No full textWeb Single Sign-On (SSO) login is a popular alternative to password-based login in current authentication systems. SSO services enable users to use accounts registered with identity providers (IdPs) such as Google and Facebook to login on multiple relying party (RP) websites. Common web SSO deployments are based on the OAuth 2.0 authorization standard which enables RPs to both authenticate users and access a subset of a user's personal information from an IdP. This thesis pursues three goals related to user privacy in OAuth-based web SSO implementations. First, we build OAuthScope, a tool that extracts OAuth protocol data from RP sites. We use it to conduct an empirical investigation of privacy implications for users of OAuth implementations in RP websites most visited by users across five countries. We categorize user data made available by four IdPs (Google, Facebook, Apple, and LinkedIn) and evaluate the types of user data accessed by RPs through these IdPs. Our results reveal considerable variations in the categories and amounts of user data accessed by RPs, including differences across site versions in different countries. Second, to improve the transparency of user data accessed by RPs, we design and implement SSOPrivateEye (SPEye), a browser extension tool to inform users about the privacy consequences of choosing SSO login options. SPEye extracts information about permission requests made by RPs to enable users to compare SSO options before making a login choice. Third, we conduct a user study to identify factors that influence participants when choosing from SSO and non-SSO login options. We compare login decisions made by participants before and after viewing comparative information on the user data accessed by RPs through different SSO choices. We find that usability preferences and inertia influence a majority of login decisions when presented with a list of SSO and non-SSO choices, while privacy-related reasons were most common after participants viewed the user data requested through each SSO choice. Through these three goals, we highlight and tackle SSO privacy issues affecting users, and provide insights on further improving privacy in OAuth systems
Development of a Material Selection Procedure for Natural Gas Pipelines based on the Crack Tip Opening Angle
No full textIn this thesis, extensive finite element simulations of ductile fracture propagation were analyzed using the cohesive zone model (CZM) and the constant CTOA model. The CZM was used to examine the effect of loading mode on the CTOA through comparing the results of a DWTT model to that of a pipe model. A novel constant CTOA model was proposed in which it was integrated into the explicit time integration solver for dynamic simulations. The proposed model was compared with previous published numerical data to serve as verification and then compared to recent experimental data for validation. The proposed model reduced the runtime from previous implementations by 94% while maintaining less than 2% difference. The analysis of the experimental data was the first use of the constant CTOA model to reproduce experimental fracture velocity data. Smoothed particle hydrodynamics was implemented to simulate the effect of backfill during fracture propagation simulations. Several aspects of the modelling techniques were investigated such as the effect of the backfill model size and particle size, as well as various backfill material properties. The effect of each of these parameters was quantified through the effect on the steady state fracture velocity of the model, and effect on the shape of the fracture resistance curve. The constant CTOA model was combined with the SPH model to calculate steady-state fracture velocities for an API X80 and X100 steel with various geometries. This was done to generate a database of fracture resistance data. The fracture resistance data was used to determine the arrest CTOA for various materials and geometries. Using the fracture resistance data, an equation was determined to calculate the arrest CTOA required for a given material, geometry, and operating pressure and backfill. This equation was compared with two other previous arrest CTOA models. The predictions were shown to agree well with X100 experimental data. The arrest methodology was further validated through examining a recent full scale burst test performed on a grade 550 pipe. The CTOA derived fracture resistance curves were shown to estimate the fracture velocity of each of the pipe sections better than the original TCM