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Semantic Relatedness or Arousal: What Drives Enhancement of Memory for Emotional Words?
No full textEmotional stimuli are typically better remembered than neutral ones. Two accounts have been proposed for the advantage in memory for lists of words. The first is that it arises due to enhanced arousal, and the second is that it arises due to the inherent semantic relatedness of emotional words. We compared these accounts by examining memory performance for lists of words in which arousal and relatedness were manipulated. In three experiments (n = 418), conducted online, participants were asked to encode lists containing words that were either unrelated, related, or emotionally valenced, followed by free recall tests. List type was manipulated within-subject. Participants also rated the arousal and emotional valence they experienced for each word using a Self-Assessment Manikin (SAM). Latent semantic analysis (in Experiment 1) and free association norms (in Experiment 2) were used to match the semantic relatedness of words in the emotional (negative) and related lists. Free recall of related and negatively valenced word lists was significantly higher than for unrelated lists. In Experiment 3, we used free association norms to create emotional lists of mixed valence (negative and positive), effectively lowering semantic relatedness within the list, but keeping arousal high. Despite lowering relatedness of the emotional word lists, recall of related and emotional word lists was again of similar magnitude, with memory for both significantly higher than for unrelated lists. Importantly, using logistic regression we showed that participants’ arousal ratings predicted recall in all three experiments. Findings suggest that arousal, not semantic relatedness, explains why memory is better for lists of emotional words
ReSlide: Towards Effective Presentation Authoring for Evolving Narratives and Contextual Constraints
No full textAuthoring slides for a public presentation requires speakers to navigate multiple contextual constraints that directly shape how content is structured and delivered. We first conducted a formative study with ten experienced presenters to understand what constraints are prioritized and how they influence slide deck creation. We identified three key constraints---time, audience, and communicative intent---and challenges in integrating them into slide authoring for a single presentation and long-term needs with diverse narratives. We designed ReSlide, a presentation authoring tool that helps presenters create and reuse slides by bridging contextual constraints with evolving narratives. We evaluated ReSlide in a within-subjects study with 12 participants against a baseline tool, and in an exploratory study with eight professional presenters using only ReSlide. Results indicate that Reslide's novel features of constraint awareness and multi-granular slide reuse helped presenters effectively craft presentations in both one and multiple authoring cycles
Hydrological responses of critical aquatic habitat in Wood Buffalo National Park for the world’s only naturally reproducing migratory population of whooping crane to past climate variation
No full textThe only wild, self-sustaining population of endangered whooping crane (Grus americana) breeds within a remote, pond-rich, groundwater discharge region in and adjacent to Wood Buffalo National Park where there is concern for habitat degradation by climate change. Due to their small area and volume, shallow ponds respond rapidly to changes in climate and are vulnerable to desiccation, which can reduce breeding success by altering food availability and encounters with predators. Hydrological information is scant in this remote region, and longer time-series of data are needed to anticipate how shallow water breeding habitat will respond to future climate warming. Here, contemporary measurements (2022-2023) at three shallow ponds that range from weakly to strongly connected to groundwater are integrated with paleolimnological analyses, which span the past ~300-400 years and capture the cold, arid Little Ice Age and subsequent warming, to improve understanding of hydrological responses to climate variation. Correspondence of pond water ẟ18O inferred from sediment carbonate (carbonate-inferred ẟ18Opw) with contemporary measurements of pond water ẟ18O indicates that carbonate-inferred ẟ18Opw provides a reliable methodology to reconstruct past variation in pond water ẟ18O. Evidence suggests two of the three ponds desiccated during the mid- and late 1700s when the climate of the Little Ice Age was arid. At pond SK 31, where connectivity to groundwater is weak, carbonate-inferred ẟ18Opw increased during this interval and exceeded the contemporary estimate of the terminal basin steady-state isotope composition, indicating strongly negative water balance prevailed due to evaporation. Similar strong net evaporation and near-desiccation has been detected during the same time interval from a record of cellulose-inferred lake water δ18O at a shallow upland lake located ~175 km to the south (Wolfe et al., 2005), which provides confidence in the interpretations based on carbonate-inferred δ18Opw at SK 31. At pond SK 58, where connectivity to groundwater is strong but desiccation occurred in 2023 and 2024 likely by vertical seepage, the stratigraphic record of carbonate-inferred δ18Opw reveals no evidence of enrichment by evaporation during the mid- and late 1700s. A distinctive peak in C/N ratios in sediment deposited ~1790 suggests, however, that an apparently rare desiccation, or near-desiccation, event may have occurred by vertical seepage when SK 31 and PAD 5 also nearly desiccated by evaporation. Smaller C/N-ratio peaks in ~1908 and ~1998 may capture two other short-lived near-desiccation events at SK 58. Recent observed desiccation at SK 58 in 2023-2024 occurred when unusually arid climate conditions resulted in a decline in water level of 60 cm in Great Slave Lake to the lowest levels recorded by the 84-year-long record. At pond SK 26, low carbonate-inferred ẟ18Opw values throughout the ~280-year record provide no evidence of drawdown by evaporation and suggest there may have been shifting sources and discharge of groundwater, which may be indicative of the spatial and temporal variability of past hydrological conditions across this complex landscape. Overall, pond desiccation, including the recent drying of SK 58, appears to be a largely rare occurrence since 1800 but may become increasingly common with ongoing climate change
Durable attitude change using active processing: A longitudinal study on the effects of AI dialogue
No full textThis study investigates whether AI-driven conversations can produce durable attitude change toward controversial policies, specifically legal kidney markets and free trade. In Study 1, participants interacted with a GPT-3.5 chatbot using utilitarian, deontological, emotional, and narrative arguments. Attitudes were measured immediately, one week, seven weeks, and eighteen weeks after the intervention. All strategies shifted attitudes in the short term, with most changes remaining durable after one week. However, only narrative arguments remained effective at seven weeks, with aggregate change persisting at eighteen weeks. Neither argument type nor decision-making style interacted to affect persuasiveness. Study 2 found in-group/out-group messaging effective but equivalent. Vivid memory of AI interactions predicted positive attitude change, while accurate memory of the argument had no effect. These findings suggest that conversational AI can produce long-term attitude change through active cognitive processing, demonstrating its potential as a scalable tool for shifting public attitudes on complex issues through interactive engagement
Exotic constructions on covers branched over hyperplane arrangements
No full textThe purpose of this thesis is to study and construct geometric structures on 4-manifolds from a starting point of combinatorial objects.
In part as a consequence of embedded surfaces and codimension two submanifolds coinciding in dimension four, many of the tools that are used in higher dimensions fail or are underwhelming when applied to 4-manifolds. For this reason, the development and advancement of techniques that are applicable to 4-manifolds are of particular interest and importance to low dimensional topologists. The general techniques of interest are those that either construct a 4-manifold in a novel way or find interesting embedded submanifolds.
Consequently, we shall contribute to the study of 4-manifolds by investigating ways to construct 4-manifolds with positive signature in addition to describing construction methods that can guarantee the existence of algebraically interesting embedded symplectic submanifolds.
In this thesis we investigate how the combinatorial data of line arrangements and the algebraic data of their complements in rational surfaces can be utilized to construct symplectic 4-manifolds with arbitrarily large signatures through the method of branched coverings. In general, we not only show that these line arrangements can be used to provide asymptotic bounds for the existence of symplectic 4-manifolds but we also show that for any line arrangement, there exist symplectic branched covers with sufficiently nice geometric and topological properties. Namely, we show they contain embedded symplectic surfaces which carry their fundamental group
Characterization of prostate tumor spheroid growth and response to treatment using dynamic optical coherence tomography
No full textProstate cancer, the most prevalent cancer in North American men, is often treated with radiation and in the case of advanced disease, with the first-line chemotherapeutic docetaxel (DTX). The use of in vitro cell culture as a model for in vivo patient tumors has been instrumental in understanding the cancer biology underpinning tumor development, progression, and treatment. Conventionally, in vitro cells were cultured as 2D monolayers on hard, flat surfaces. However, it has become well understood in the last half-century that the behavior of in vivo tumors is better replicated by small 3D aggregates of in vitro cancer cells called tumor spheroids. While cells proliferate along the spheroid periphery, the center of the spheroid succumbs to starvation and waste build up. In between forms an intermediate layer of hypoxic and non-proliferative quiescent cells: two characteristics associated with treatment resistance.
Despite the physiological pertinence of spheroid culture, its 3D nature challenges conventional biological methods. Moreover, cell culture geometry influences cell behavior not only during treatment, but in post-treatment recovery and throughout measurement as well. The clonogenic assay is a gold standard method for quantifying cell survival following treatment; however, it requires spheroids to be disaggregated and cultured in 2D for colony formation, which alters the cellular response. Proliferation assays quantify cellular activity inside intact spheroids, but similarly lack spatial resolution. Although fluorescence microscopy (FM) enables spatially resolved spheroid evaluation, it remains largely qualitative rather than quantitative. Proliferation assays and FM also require the addition of exogenous agents that are invasive to the sample and struggle to penetrate large spheroids. Alternatively, optical coherence tomography (OCT) enables non-invasive, high-speed, volumetric imaging of biological tissues with cellular resolution. Analysis of temporal OCT intensity fluctuations generates dynamic OCT (dOCT) images that can provide a quantitative and spatially resolved measurement of cellular activity throughout the spheroid.
Nevertheless, investigating treatment response in spheroids is known to be tedious and time consuming, and some questions of interest cannot be accessed experimentally with adequate accuracy. As such, mathematical in silico models of spheroids have become increasingly prevalent. The heterogeneity inherent to in vivo tumors and in vitro spheroids is recapitulated by discrete in silico methods like agent-based modeling (ABM). These methods simulate each cancer cell as an individual “agent” that responds to neighboring cells, nutrients, drugs, and other components of its local environment. In particular, the cellular Potts model (CPM) is a form of ABM with phenomenological utility, given adequate validation to experimental observations. As such, it can describe, visualize, interpolate, and potentially even extrapolate experimental data to guide future experiments.
This dissertation investigated and validated emerging and under-used in vitro tools for characterizing prostate tumor spheroid growth and response to treatment with radiation and DTX. First, I created a semi-automated masking process to isolate spheroids from volumetric OCT images for high resolution morphological analysis. For analysis of dynamic motion, I generated dOCT images using a frequency banding method that had only been previously subject to qualitative evaluation. Then, I developed a technique to quantify cellular activity in volumetric dOCT images of masked spheroids. Visual and quantitative comparison of live and formaldehyde-fixed spheroids imaged with dOCT and FM confirmed that dynamic motion measured with the dOCT method was associated with cellular activity. To mitigate influences unrelated to cellular activity, the average measurement of formaldehyde-fixed spheroids was subtracted from quantitative dOCT measurement as background. Post-treatment recovery of prostate tumor spheroids exposed to DTX was investigated with repeated measurement via Alamar Blue (AB) proliferation assay and longitudinal observation of clonogenic assay colony formation.
Excellent agreement was observed between the quantitative dOCT method and AB proliferation assay over two weeks of longitudinal spheroid growth. Volumetric morphological analysis supported the measured cellular activity trends. However, fixation-subtraction could not be performed in a spatially sensitive manner and the dOCT images failed to resolve the longitudinal formation of a necrotic spheroid core that was observed via FM. Nonetheless, dOCT images and quantification of spheroids post-radiation demonstrated good agreement with FM and AB, respectively. Spheroids treated with radiation and DTX demonstrated better survival compared to monolayer culture. Monolayer culture treated with low dose DTX demonstrated higher post-treatment cellular activity and faster colony formation, but clonogenic survival remained lower than the untreated control. This effect was also observed in spheroids, albeit to a lesser extent. Experimental observations were probed with novel in silico CPMs of prostate tumor spheroid treatment.
This thesis serves as a step towards validating emerging and under-used in vitro tools for spheroid evaluation in well-studied conventional cancer treatments. Once validated, these in vitro tools are particularly well suited for discovery and testing of novel targeted cancer treatments since spheroid protein and gene expressions are more physiologically representative than monolayer culture
Alert Systems for Missing Persons Living with Dementia: From Policy to Implementation
No full textBackground: People living with dementia are at risk of going missing and experiencing serious harm. Alert systems, such as the BC Silver Alert in Canada, Silver Alert in the United States, and Purple Alert in Scotland, use mobile apps or media to notify the public and assist in locating missing persons with dementia. Policies regarding alert systems exist in the United States. Two Canadian provinces mention Silver Alert in Missing Persons Acts, but these legislations are not associated with implementation of these systems. Little is known about how alert systems for older adults are implemented and adopted, specifically in Canada.
Objectives: This dissertation examined the development and implementation of alert systems for missing persons with dementia across Canada, Scotland, and the United States through three studies. Study 1 explored user experiences implementing alert systems and related policies, drawing on stories and insights from individuals who went missing, their care partners, and those involved in search efforts. Study 2 examined the conditions surrounding alert system implementation, using the Knowledge-to-Action (KTA) Framework. Study 3 explored multi-level factors influencing implementation of alert systems, guided by the Consolidated Framework for Implementation Research (CFIR).
Methods and Results: Using a multiple case study design, data were collected through policy document review, interviews, and focus groups with 40 stakeholders, including people with lived experience, first responders, service providers, policymakers, technology developers, and researchers. Data from the three studies were analyzed using thematic analysis. Study 1 underscored the importance of stakeholder engagement, legislative support, timely police reporting, coordinated search efforts, and public education in implementing alert systems and locating missing persons. The findings also highlighted the emotional impact of missing incidents on people living with dementia and their care partners and challenges such as inaccurate tips, which can delay search efforts. Study 2 findings revealed variability in alert system implementation and related policies and identified individual and organizational barriers, including limited understanding, privacy concerns, alert fatigue, sustainability, and accessibility. Findings from Study 3 identified key factors influencing alert systems implementation across CFIR domains: Intervention Characteristics (relative advantage, evidence strength and quality, cost), Outer Setting (end user needs and resources, cosmopolitanism, external policy and incentives), Inner Setting (culture, available resources), Characteristics of Individuals (knowledge and beliefs about the intervention), and Implementation Process (planning, engaging stakeholders, reflecting and evaluating). Findings from the three studies emphasize the importance of integrated implementation of alert systems that actively engage stakeholders, address contextual factors and challenges, and ensure equitable access for all users.
Contributions: This dissertation provides an understanding of how current alert systems and related policies are developed and implemented to locate missing persons with dementia. Effective implementation of alert systems relies on cross-sector collaboration, clear and consistent policy, user-centered design, sustained funding, dementia-specific training and public education, and continuous evaluation. The framework and recommendations proposed in this dissertation offer practical guidance for policy and practice in alert system implementation to reduce the risks associated with going missing and uphold the safety and dignity of people living with dementia. Sustainability of any alert system implementation relies on rigorous and compelling evaluation of impact
Rooted Elsewhere: Understanding the impact of immigration on health and wellbeing from the perspective of Black immigrant women in Ontario
No full textIntroduction
Canada has long relied on immigration to shape its demographic landscape, social fabric, and economic development. Historically, immigration policies have favoured white European settlers, but changes to the Canadian Immigration Act opened pathways for more diverse populations, including Black immigrants from the Caribbeans and various African countries. However, Black immigrants, particularly women, continue to face systemic inequities in healthcare, employment, housing, and other areas of life. Black immigrant women often carry the compounded weight of racialized and gendered expectations as they navigate caregiving responsibilities, financial pressures, and resettlement barriers in their new socio-cultural context in Canada. When combined, these social determinant of health can negatively impact their health and resilience as they resettle in Canada. Canadian immigrants are rigorously vetted for the positive educational, health and economic impact they can make to the economy however, their health start to decline after their arrival to the country. Though studies abound establishing patterns linking unmet needs, structural and institutional inequity to immigrant health, for Black immigrant women, health is further shaped by intersecting forces such as race, gender, and migration. While quantitative studies have captured broad patterns in immigrant health, they often fail to capture the lived experiences behind those numbers. This study offers critical insight into the social and emotional complexities of resettlement, health-seeking behaviours, and identity negotiation of immigrants and their impact on physical and mental health. It contributes to a growing body of qualitative scholarship that centres the voices of Black immigrant women in Canada, by offering a deeper understanding of how immigration and resettlement experiences shape their health and well-being.
Research Aim
This thesis explores the multifaceted immigration and resettlement experiences of Black immigrant women in Ontario, Canada, with a focus on the implications for their physical and mental health. To capture the depth and complexity of the participants’ experiences, this thesis is separated into three papers, each drawing from the same research question but having their own distinct aim.
Paper one examines the resettlement challenges specifically encountered by Black immigrant women as they settle and integrate into the Canadian society. It highlights how meeting Canadian immigration eligibility criteria does not ensure effective integration into the Canadian society. It showcases specific resettlement challenges and the resultant impact on their health and wellbeing. Paper two captures the employment experiences of Black immigrant women in the Ontario labour market and produces a three-stage employment narrative common to all participants. Also, paper two highlights the physical and mental health impact associated with the three different stages, along with the different coping strategies deployed by the women. Paper three explores how Black immigrant women make sense of their immigration and resettlement experiences and how the meanings they ascribe to their experiences impact on their health and wellbeing. These meanings significantly influence their choices and behaviors and profoundly impacts their self-identity and engagement with the Canadian society.
Methods
This thesis employs a qualitative approach to immigrant health research. Purposive sampling recruited a total of twenty-two Black immigrant women living in Ontario, aged 18-54 years. The women participated in virtual and in-person semi-structured interviews that lasted between 45 minutes to two hours. Three analytical approaches were used. First, thematic analysis was utilized in paper one to systematically code and interpret the broader resettlement challenges encountered by participants, such as the persistent devaluation of foreign credentials, experiences of racialized housing discrimination and negative dietary acculturation. Paper two drew on Reissman and Polkinghorne’s narrative analysis approaches to construct a framework that mapped participants’ employment stories across three distinct phases: the initial entry to the labour market, the early employment period, and the longer-term navigation of workplace environment. Paper three used Interpretative Phenomenological Analysis (IPA) to delve into how participants made meaning of their immigration and resettlement experiences within their cultural and socio-political contexts.
Findings
Findings from the thematic analysis of paper one illuminate how structural and systemic barriers were internalized by the participants, and contribute to their heightened stress, feelings of marginalization, and prolonged sense of frustration which are closely tied to both physical and mental health outcomes. The themes in paper one are: 1.) Hopes and aspiration for a better life, 2.) Facing reality, and 3.) Intentionality. Also, paper one shows that the combination of resilience level and the ability to leverage social capital determine participants’ ability to effectively integrate into the Canadian society. Participants’ employment narratives in paper two expose the emotional strain and disrupted career trajectory experienced by the participants as they tried to continue their professional path after arriving in Canada. Paper two highlights how participants experience structural and social exclusion at the workplace and the resulting negative impact on their physical and mental health. Most importantly, paper two develops a three-stage narrative model of early employment of newcomer Black immigrant women in Ontario. This model links the devaluation of credential and professional experience and racialized gatekeeping of employment to health outcomes in Black immigrant women. Further, this narrative model highlights not only the challenges encountered during the different stages of the employment journey but also how these experiences can contribute to the onset and progression of imposter syndrome (IS). The Interpretive phenomenological Analysis (IPA) method used in paper three foregrounds the embodied and affective dimensions of resettlement by showing how the participants’ identities, aspirations, and understandings of their health evolved in response to both visible and invisible pressures from their immigration. Paper three shows how participants sense of immigration was different before and after their arrival in Canada. Further, it shows that how they internalised and made sense of their experiences determined the decisions and actions they take which in turn impacted on their health and wellbeing. By privileging participants sense-making, paper three reveals the Black immigrant woman’s nuanced portrait of resilience and negotiation of self identity in their destination country.
Conclusion
Paper one highlights the feelings of disadvantage and stress expressed by all the participants as a result of their resettlement experiences of dietary acculturation, housing and healthcare discrimination. It showcases the results of the intersectionality of the participants identities and how social capital influences the extent to which participants are were able to navigate their resettlement challenges. Paper two portrays how people internalise the devaluation of their educational and professional qualifications because of systemic barriers and sexism and racism in Canadian workplaces. Further, Paper two identifies how participants experience of the imposter syndrome has far-reaching effect on their physical and mental health. Also, it shows that somatic symptoms can be easily developed as a result of workplace stress, and if they are misdiagnosed or overlooked, can lead to more serious and chronic health conditions. Paper three shows that beyond physical relocation, immigration is a deeply emotional and psychological journey shaped by the intersecting forces of gender, race and identity. Participants’ experience of racial trauma and systemic exclusion resulted in a sense of resignation to conserve their emotional energy. However, they demonstrate resilience through positive reframing and biographical reinvention to reconstruct their self identity in order to live and thrive in Canada as an immigrant.
Overall, the contributions of this thesis include:
1. A methodological contribution showing productive complementarity between Interpretative Phenomenological Analysis Narrative Inquiry, and Thematic Analysis for capturing both idiographic depth and substantive patterns across the dataset.
2. A theoretical refinement by demonstrating how the Intersectionality lens, backed by the Critical Race Theory, and Migration and Integration theories can be used to capture and categorize data for analytic navigation and story telling.
3. An empirical contribution by way of a three-stage narrative employment model for newcomer Black immigrant women in Ontario that links credential devaluation and racialized gatekeeping to health impacts.
Ultimately, this thesis affirms that immigration and resettlement, for Black immigrant women, is not just about relocating and fitting in a new country but is about renegotiating their entire self-identity in environments with limited socio-cultural and professional support. When these are not appropriately addressed, will impact negatively on their health and wellbeing in their destination country
Concert: Elementary VR Interactions Augmented By Bimanual Input
No full textMany elementary tasks in Virtual Reality (VR)—such as pointing, locomotion, and command selection—are still predominantly performed through unimanual interaction, even though the non-dominant hand often remains available. When these tasks require multiple sequential steps, their frequent use can increase overall interaction time and user effort. By engaging both hands in complementary roles, some of these tasks can be streamlined into more efficient, parallelized actions without sacrificing intuitiveness. This thesis, Concert, investigates how bimanual input can optimize such underexplored opportunities through three novel interaction techniques. The first, Conductor, is an intersection-based 3D pointing method where the dominant hand controls an aiming ray while the non-dominant hand positions an intersecting plane to determine cursor depth. Compared to Raycursor, a state-of-the-art VR pointing technique, Conductor enables faster and more accurate target selection. The second project, Fly The Moon To Me (Locomoontion), extends Conductor to 3D object manipulation for locomotion, integrating vertical (height) and horizontal (planar) adjustments into a single fluid operation. Users generate a preview copy of a target object, reposition it precisely in 3D space, and then align the original object and surrounding environment to the preview. In a teleportation task, Locomoontion outperformed Point & Teleport and Point & Tug, reducing completion time and physical effort. The third project, Drum Menu, accelerates command selection through bimanual shortcuts inspired by marking menus. Users select commands by joystick rotation, stroke drawing, or directional pointing, with the bimanual variant granting simultaneous access to two menu levels. In user studies, bimanual configurations were faster than unimanual ones for a 4-item layout, with participants preferring the bimanual joystick menu; however, 8-item layouts increased error rates among experienced users. Collectively, these studies show that many common VR tasks can be made more efficient through carefully designed bimanual interaction, providing concrete design guidelines for integrating both hands into future immersive systems
How Could I Have Known? How Undiagnosed ADHD Instantiates Hermeneutical Injustice
No full textIn this thesis, I argue that some people with undiagnosed ADHD face hermeneutical injustice
in light of their missed diagnoses. Drawing upon Miranda Fricker’s account of hermeneutical
injustice, José Medina’s contribution to Fricker’s original account, Gaile Pohlhaus’s account
of willful hermeneutical ignorance, Kristie Dotson’s concept of pernicious ignorance, Jon
Leefmann’s concept of epistemic self-trust, and a variety of empirical sources, I explore the
particular kinds of harm undiagnosed ADHDers face and explain why their marginalization
is also wrongful, not just harmful. Using Fricker’s account, I aim to demonstrate how their
inability to participate in meaning-making practices results in a lack of accurate
hermeneutical resources within the dominant sphere and perpetuates their marginalization.
Additionally, I rely on Pohlhaus’s account of willful ignorance as a framework for
understanding how this hermeneutical marginalization is wrongful; although accurate
resources about ADHD exist, they are often willfully ignored and excluded from dominant
resources. In light of their unjust lack of hermeneutical power, I argue that we ought to
consider undiagnosed ADHDers victims of hermeneutical injustice