VictorJuiz/thesis huggingface dataset:
Self-motion Perception and Multisensory Integration in Older Adults

Aging is associated with changes in how our brains combine sensory information when perceiving self-motion. Despite age-related changes in sensory integration, little is known about whether multisensory self-motion perception changes in older adults (OAs). Understanding such changes is important since OAs are particularly vulnerable to errors during self-motion, which can increase their risk of injury (e.g., when walking, driving). Vestibular cues are very important for self-motion perception, yet how vestibular perception changes with older age and age-related sensory declines is understudied. Therefore, in Chapter 2, I explored whether vestibular perceptual thresholds differ between healthy OAs (i.e., no sensory/cognitive decline) and younger adults (YAs), for two different motion types (heave and pitch). Thresholds were measured using two different perceptual tasks: 1) detection task, and 2) discrimination task. Postural stability was also assessed. OAs demonstrated higher (worse) detection thresholds than YAs for both motions. Larger postural sway in OAs was also associated with higher vestibular thresholds. Age-related hearing loss (ARHL) is highly prevalent in OAs and is associated with increased falls risk. Therefore, using the same paradigm as Chapter 2, in Chapter 3 I evaluated whether higher vestibular perceptual thresholds are observed in individuals with ARHL than those with normal hearing. Here, OAs with ARHL showed higher pitch discrimination thresholds than those with normal hearing. Hearing loss in the low-frequency ranges also predicted worse pitch detection. Given that older age (Chapter 2) and ARHL (Chapter 3) were shown to predict poorer self-motion perception, in Chapter 4 I evaluated whether self-motion perception could be improved with training. Specifically, I trained OAs and YAs on a visual-vestibular heading-discrimination task. While OAs showed poorer overall precision than YAs, both groups showed improved precision post-training for the sensory condition with the lowest pre-training precision (visual-only). A sub-group of OAs who initially could not perform the visual heading task demonstrated greatly improved performance post-training. Collectively, I show that while healthy aging and common age-related sensory declines may be associated with poorer self-motion perception, training can potentially be used to improve these abilities. Together, these results may have implications for informing fall/collision prevention strategies.

Keywords: Falls
Mobility
Multisensory Integration
Sensory perception
Vestibular
Vision
Advisor: Campos, Jennifer L
Standing on the Shoulders of GIaNTs: Drawing Queer and Trans Education Possibilities Together

Standing on the Shoulders of GIaNTs is an exploration of the desires of 2SLGBTQ children and children of 2SLGBTQ parents in education, and the desires of their parents. It is guided by the questions: 1. How do 2SLGBTQ children, and children from 2SLGBTQ families, envision education spaces and programs that meet their needs?2. How might 2SLGBTQ caregivers (parents and others) and the caregivers of gender independent children, envision spaces and programs that meet their needs? 3. What would happen if as a parent-and-child researcher team, we engage caregivers, and children in co-imagining the education spaces as 2SLGBTQ cultural spaces? This was a co-research project: a partnership between me, an adult queer and trans researcher, and my elementary nonbinary child. Participants were recruited within my social networks, and included 17 children (ages 4-12) and 12 adults from eleven households. While recruitment was for 2SLGBTQ children and children of 2SLGBTQ parents, the participant group included 10 adults who identified as other than cis, and 14 children who identified as other than cis, meaning that the majority of participants were adults on the trans spectrum parenting children on the trans spectrum, or children on the trans spectrum being raised by adults on the trans spectrum. This allowed us to centre trans people, trans culture and trans epistemologies. It required the development of ethical frames of care, attending to ethical responsibilities to community, to children, and to myself. Data was collected through semi-structured interviews and invitations to participants to draw their ideal learning environment. Drawing was used as a research technique, as a way of taking visual fieldnotes, for analysis and to share the work. Images were described using the Prospect Descriptive method, as a way of attending to the intent of the people creating the images, rather than evaluating. Interviews were recorded and transcribed before being coded. I used the practices of practitioner research to interrogate my own practices as a researcher and as a parent, to learn from my participants, and to ask better questions of myself. We learned that outness and pride are protective, that children desire truly equitable learning environments that intersectionally attend to the work of justice, and that children have much to say about what learning could be like - if they are only asked.

Keywords: children's rights
co-research
COVID
queer
trans
visual methods
Advisor: Simon, Rob
Numerical Modeling Of Tectonic Plates Application of Artificial Neural Networks in Earthquake Seismology

This research utilizes two distinct forward predictive modeling techniques to examinethe continuous large-scale viscous-plastic deformations and discrete small-scale brittle crustal responses in two different tectonic settings to pave the way to construct an integrated forward predictive platform for the parallel study of geodynamic evolutions and short-long-term seismic response predictions. Using the ASPECT geodynamic code, a series of 2D and 3D numerical models were developed to examine the dependency of mantle lithosphere removal on the initial conditions and rheology of crustal and mantle components in the Anatolian regions. The 2D model predictions provide crustal compositions that suggest states of stability or the onset of delamination of mantle lithosphere and the effect of lower crust eclogitization on the removal mechanism. In addition, the models suggest that in subcontinental regions with evidence for delamination of the mantle lithosphere, the activation energy of the upper mantle and mantle lithosphere can be approximated as an average between dry and wet olivine close to 485 ×103kJ/mol. The 3D models predict that a 3-5 cm/yr initial convergence rate of the African plate and its gradual reduction to the current 1 cm/yr would result in ∼300-500 km trench retreat leading to the current anomalous extension rates in the extensional basins in the western Anatolia. To build the framework for the study of discrete small-scale seismic responses ofgeodynamic evolutions, non-rule-based generalizable artificial neural algorithms were utilized to investigate seismic events in the Southern California region. The region was chosen for its similarity to Anatolia in terms of seismic waveform character, network complexity, and proximity of local events to populated areas. The models predicted source magnitudes with 98.39% accuracy with a maximum absolute deviation of 0.3 units and the epicentral distance with 91.35% accuracy with ±10 km error. On the other hand, the models classified the Up and Down first motion polarity with Precession and Recall measures in the range [97%, 98%], and distinguished true earthquake from impulsive noise records with 99% Recall and Precession values for both classes, in other words, 1% false alarm or missed alerts. All single-signal predictions were processed within 4 to 6 milliseconds.

Keywords: Artificial Intelligence
Deep Learning
Delamination
Earthquake Early Warning System
Geodynamics
Seismology
Advisor: Pysklywec, Russell
The Hopeless and the Free-riders: Group size and Group Goals Shape Efficacy and Contributions to Collective Tasks

To what extent can ordinary people affect collective outcomes? Although individuals often possess objectively little capacity to change outcomes that are dependent on many individual inputs, subjective beliefs about one’s ability to affect a given collective outcome vary widely. In this dissertation, I examine how variation in efficacy beliefs and subsequent cooperation in collective tasks are shaped by two features inherent to collective tasks: the number of people in the group, and the proportion of the group that needs to contribute for the desired group outcome to occur (the provision point). Collective tasks often take the form of a social dilemma, in which individual interests are in conflict with that of the group. Social dilemma researchers typically assume that individuals are less likely to cooperate in larger groups, but empirical findings are inconsistent. I aim to elucidate the effect of group size on individuals’ collective behavior by focusing on how group size affects perceptions of efficacy. I present four studies in which unacquainted individuals were provided with the opportunity make private contributions toward a group goal. In Chapter 2, I demonstrate that group size is inversely related to two related efficacy constructs: As groups increase in size, perceptions of self-efficacy decrease while perceptions of collective-efficacy increase. I provide evidence that self-efficacy predicts intentions to cooperate to a greater extent than does collective efficacy. I also examine how provision points levels affect efficacy beliefs and identify conditions in which the presence of a provision point can hinder cooperation. In Chapter 3, I use a two-party voting paradigm (which involves a natural provision point) and demonstrate that both group size and perceived distance to the provision point influence self-efficacy and intentions to vote. In Chapter 4, I extend the findings in Chapter 2 to actual contributions in social dilemmas. Furthermore, I demonstrate that perceptions of the provision point as either unrealistically high or excessively low can help to distinguish between two categories of non-cooperators in social dilemmas: (1) people who predict that the group will achieve its goal without them (“free-riders”) and (2) people who expect the group to fail (“hopeless”).

Keywords: collective action
cooperation
social dilemmas
Advisor: Plaks, Jason E
Articulatory Difficulty in L2 Spanish

This thesis investigates the role of articulatory difficulty (AD) in the acquisition of L2 Spanish by L1 English speakers. Previous work has revealed that AD is one of the primary sources of difficulty in L2 speech (Yavas, 1997; Colantoni & Steele, 2007; 2008), yet models of L2 speech focus primarily on implicational markedness or learners’ challenges with perceptual categorization to explain relative difficulty. The current study sets two objectives: first, to establish an AD hierarchy for a particular set of Spanish sounds ([m t β̞ ɣ̞ ɲ χ r]) for L1 Spanish and L1 English-L2 Spanish speakers; second, to determine to what extent the AD hierarchy can predict target-like production of L2 Spanish segments by L1 English speakers in a communicative speech task. 20 L1 Spanish and 25 L1 English-L2 Spanish speakers with varying levels of L2 Spanish oral proficiency, all recruited in Madrid, Spain, participated in the study. In Experiment 1, a perception test was conducted to rule out misperceptions as a possible source of non-target-like production. In Experiment 2, production data elicited via an articulation task were used to create an AD hierarchy. The following hierarchies were observed (from least to most difficult consonants): L1: [m β̞] < [t] < [ɣ̞ ɲ χ r]; L2: [m] < [t β̞] < [ɣ̞ ɲ] < [χ r]. In Experiment 3, participants performed a picture description task that elicited production of the target segments [β̞ ɣ̞ ɲ χ r]. Mixed effects modelling revealed that the AD hierarchy from Experiment 2 was a predictor of target-like L2 production. For both the L1 controls and L2 learners, target-like realizations decreased as AD increased. We argue that this reflects the effect of articulatory constraints on speech production in general. However, a negative correlation between target-like production and AD was observed in the least proficient speakers, which suggests that the effect of AD varies with L2 oral proficiency. We argue that AD must be integrated into models of non-native phonetic and phonological acquisition and discuss the nature of a model capable of predicting difficulty arising in both perception and production.

Keywords: complexity
phonetics
phonology
pronunciation
second language acquisition
second language speech
Advisor: Colantoni, Laura
Steele, Jeffrey
Teacher AND Mentor: Exploring the Characteristics and Benefits of Informal Mentoring Relationships between Teachers and Students Considered ‘at Risk’ in Secondary School

Views and definitions of mentoring continue to evolve and become more expansive in the literature (Mullen & Klimaitis, 2021). Although studies have explored the role of mentoring for and by teachers and leaders, further study of the mentoring relationship between a teacher and a student considered ‘at risk’ in secondary school is needed. Using an exploratory approach, this qualitative study investigates informal mentoring relationships between teachers and secondary school students considered ‘at risk’ in Ontario, Canada to determine the characteristics and potential benefits of such a relationship. Using semi-structured interviews with seven mentors and six mentee participants, I examined the following questions: a) What are the characteristics of informal mentoring relationships between teachers and students considered ‘at risk’ within the secondary school context in Ontario? b) How are informal mentoring relationships between secondary school teachers and students considered at risk developed and maintained? c) What are the benefits of informal mentoring relationships as identified by the teachers and students who experienced such a relationship within the context of a secondary school in Ontario? i) What are the perspectives of the mentors and mentees on the connections between informal mentoring relationships and mental health and well-being? Findings reveal characteristics integral to a positive informal teacher-student mentoring relationship with youth considered ‘at risk’ that include trust, time, listening, authenticity, and providing a safe space. This study showed how mentoring relationships were initiated by classroom teachers noticing the need for additional support. Mentor-teachers then reached out to a support person within the school. Mentors and mentees in this study commented on the connection of the mentoring relationship to improved mental health and well-being. Some participants indicated that the relationship was lifesaving. The final finding was that the role of the educator is both teacher AND mentor. When teachers know their students beyond them being faces in the classroom, a community can grow where good teaching includes providing guidance and support to students. This study identifies the characteristics and benefits of mentoring relationships for the well-being of mentees and explores reframing the role of the teacher to include greater attention to mentoring.

Keywords: benefits
characteristics
formation
mental health and well-being
mentor
relationships
Advisor: Gagné, Antoinette
Broad, Kathy
Moving Forward: Body Image, Social Support, and Physical Activity among Adolescents and Young Adults Living with and Beyond Cancer

Adolescents and young adults diagnosed with cancer (AYAs) experience many side effects resultant from treatment that can affect their physical, psychological, and social well-being. Physical activity (PA) is a non-pharmacological strategy that can help manage treatment-related side effects, yet many AYAs are not sufficiently active. Better understanding factors that impact PA engagement and experiences is crucial. Of particular interest, body image and social support are two factors that may affect PA during and after treatment. This research program consisted of three interrelated studies to better understand the association between PA, body image, and social support among AYAs. Study 1 utilized a scoping review to summarize the available evidence on body image among AYAs, and to identify the theories, models, measures, and methods used to assess body image. Findings indicated that body image was associated with a number of factors, including social support and PA. Further, the body image measures used with AYAs widely varied. Using a qualitative design (semi-structured interviews) and a purposeful sample of AYAs who were previously active prior to cancer diagnosis (n = 12), Study 2 explored the experiences of PA re-engagement after cancer treatment. Four themes were generated in the analysis, which collectively described facilitators (e.g., supportive others, resuming ‘normality’) and barriers (e.g., body concerns, unwelcoming gyms) to PA re-engagement. In Study 3, a cross-sectional survey design was used to examine the relationships between body image, social support, and PA among AYAs on and off treatment (n = 119). Findings demonstrated that social support and body image were directly associated with PA. Collectively, this work highlighted the unique experiences of AYAs, emphasizing the dedicated attention needed among this population. Findings underscored factors that contribute to PA participation and experiences. These studies provide groundwork for further examining how and in what contexts PA, body image, and social support are related. The results are important given the beneficial role of PA in managing side effects and increasing longevity. Findings from this research program provide researchers and practitioners with foundational knowledge that can be used to inform the development of strategies aimed at supporting AYAs during and after treatment.

Keywords: adolescents
body image
cancer
physical activity
social support
young adults
Advisor: Sabiston, Catherine M
Studying the Regulation and Function of Biomolecular Condensates with In vitro Reconstitution

A central dogma in biochemistry is that a protein’s function depends on its fixed three-dimensional structure. However, bioinformatics analysis predicts that the majority of human proteins (~58%) contain both folded protein domains along with protein regions that are entirely devoid of any tertiary protein structures, referred to as intrinsically disordered protein regions (IDRs). Despite the strong association of proteins with significant IDRs to numerous diseases, most studies tend to overlook the potential function of IDRs and focus solely on their folded domain portions. Moreover, mutations within IDRs are hard to functionally interpret and become frequently neglected or annotated as variants of unknown significance. Given these observations, we need to understand better the function and biological role of IDRs in health and disease. Recently, IDRs have been shown to drive membrane-less RNA-protein granule formation. Similar to the separation of oil and water, specific proteins and nucleic acids can phase separate and form distinct membrane-less compartments (also referred to as condensates). While we have some understanding of the phase separation process, the biological regulation of phase separation and the functional consequences of condensates remains enigmatic. Here, I use biochemistry and biophysical approaches to study the regulation and function of IDR phase separation and extend these findings to disease implications. Beginning in chapter 3, I studied the phase separation of the C-terminal IDR of the fragile X mental retardation protein (FMRP). I demonstrated that post-translational modifications, including phosphorylation and methylation, regulate FMRP phase separation which correlates with in vitro translational inhibition. In chapter 4, I studied the protein interactions and co-phase separation properties between two interacting IDRs, from FMRP and CAPRIN1. I found that different phosphorylation patterns on each IDR can regulate their co-phase separation properties and modulate their impact on deadenylation and translational activity. In chapter 5, I showed that the solvent environment of a CAPRIN1 condensate can regulate deadenylation activity by CNOT7 within the condensate. Together, these results support the functional importance of IDR phase separation and also provide new methods to study condensates. Importantly, my findings provide a platform to understand how disease mutations within IDRs may perturb phase separation leading to disruption of biological function.

Keywords: biomolecular condensates
CARPIN1
FMRP
Intrinsically disordered protein regions
phase separation
Advisor: Forman-Kay, Julie D
Uncovering the Complexities in Writing from Sources from an Activity Theory Perspective: A Cross-Case Analysis of Chinese International Graduate Students in Education

With a skyrocketing international student population from Asia at Canadian universities in recent decades, second language (L2) students’ abilities to adapt to the (inter)textual practices of their prospective discourse communities have received increased attention in L2 writing research. This thesis study aimed to uncover the complexities and heterogeneity inherent in L2 student writers’ uses of textual sources. Through a multi-case study design (Stake, 2006), I examined the textual borrowing practices of 3 first-year international graduate students from China studying Education at an English-medium university in Canada. Drawing on Engeström’s (2001) activity theory and Ivanič’s (1998, 2005) analytic framework of writers’ construction of identity, I answered 2 research questions: (1) What activity systems do students from China experience while learning to read and write in China and writing assigned papers for master’s courses in Education in Canada? and (2) What challenges do these students encounter while writing papers from sources and how do the students address these challenges, with what consequences in their writing and identities? The instruments for this multi-case study were learning history and text-based interviews with each student along with data from their written assignments and certain source texts, a learner profile questionnaire, and a reading-writing questionnaire. My analysis revealed tensions and contradictions within and between the students’ former literacy learning activity systems in China and their current writing-from-sources activity systems in Canada. These tensions and contradictions posed challenges for the students to (a) effectively process source information and accurately and appropriately present that information to demonstrate comprehension and critical thinking, evident in their patchwriting, direct copying, inappropriately quoting, transposing from Chinese sources, and paraphrasing abstracts as purported summaries of their own; (b) cultivate a genuine interest in what they wrote and manifest deep or extended learning in their writing, evident in their tendencies to cite secondary sources without reading the originals of those sources; and (c) take ownership of the knowledge co-constructed through dialogic interactions between the source authors and the students or accept their roles in shaping the double-voiced discourse in the process of writing despite their (imprecise) uses of quotations, paraphrases, summaries, and syntheses to do so.

Keywords: Activity Theory
Chinese students
English for acadmic purposes
Literacies development
Writer identities
Writing from sources
Advisor: Cumming, Alister