17876 research outputs found
Sort by
A Study of Lipid-Protein Binding Assays With α-Tocopherol Transfer Protein Using Surface Plasmon Resonance
Full text linkVitamin E is an essential micronutrient required both in early embryonic development, as well as into adulthood for proper neurological function and to prevent cell damage due to oxidative stress. Of its eight naturally occurring forms, the RRR-α-tocopherol isomer is selectively retained and used as an antioxidant in mammalian tissues. The α-tocopherol transfer protein (α-TTP) localized in the liver is responsible for the uptake and transport of RRR-α-tocopherol to the plasma membrane of hepatocytes to be secreted and delivered to target tissues throughout the body via systemic circulation. Despite knowing the bioactive role of vitamin E for centuries, the complete cyclic transport of α-tocopherol within hepatocytes remains unknown. This study investigates the binding interactions between recombinantly expressed wildtype α-TTP and unilamellar plasma membrane lipid vesicles containing various phosphatidylinositol phosphates to elucidate the mechanism of binding between α-TTP and its proposed secondary ligand – PI(4,5)P2. Using surface plasmon resonance binding assays, wildtype α-TTP alone or preincubated with α-tocopherol was injected onto lipid vesicles containing either PI(4,5)P2, PI(3,4)P2, or PI(3)P. Based on association rate constants (kon, s-1), wtTTP preferentially bound to lipid vesicles containing 4% PI(3,4)P2 (0.01896 s-1) and 4% PI(4,5)P2 (0.01174 s-1) instead of 4% PI(3)P (0.00750 s-1). In addition, concentration-dependence was observed for the rate of binding to lipid vesicles containing 2%, 4%, or 6% PI(4,5)P2. All binding assays with wtTTP preincubated with α-tocopherol produced rate constants almost three times greater than their non-preincubated counterparts. However, while wtTTP preincubated with α-tocopherol still associated fastest to lipid vesicles containing PI(3,4)P2, there was no correlation between rate of binding and increased PI(4,5)P2 concentrations. The results found in this study provide further insight into the mode of α-tocopherol transport and ligand exchange facilitated by α-TTP in hepatocytes
Watercolour Reflection in Outdoor Adventure Education: Challenging the “Meaningless Ritual” of Traditional Reflection
Full text linkThis study explores the impact of integrating artistic reflection within Outdoor Adventure
Education (OAE) programs. Merging creative expression with OAE, students form deeper
connections to the environment and engage thoughtfully with concepts like conservation,
sustainability, and stewardship. Artistic reflection provides authentic opportunities for self
expression and meaningful engagement with nature and personal experience.
Analysis of data and literature reveals that creative approaches in OAE promote critical
thinking and problem-solving skills. Students become better prepared to address ecological
challenges, developing holistic understanding and innovative solutions to the complexities of
natural systems. Artistic activities in outdoor settings prompt transformative engagement and
support personal growth, distinguishing them from traditional reflection methods.
The research also emphasizes the importance of integrating diverse cultural perspectives,
particularly Indigenous knowledge and pedagogies, within OAE. The arts serve as an inclusive
medium, allowing educators to honor different cultural experiences and create culturally
sensitive learning environments. This approach helps students build meaningful relationships
with the land and appreciate its cultural significance.
A significant finding is the positive effect of outdoor creative practices on student mental
health and well-being. Engaging in artistic activities outdoors fosters mindfulness, emotional
regulation, and a sense of flow, all of which support overall wellness. These benefits contribute
to practical emotional support for students within OAE contexts.
In conclusion, the research advocates for educators and policymakers to purposefully
integrate artistic reflection into OAE. This strategy encourages environmental stewardship,
supports lifelong appreciation of nature, and ensures outdoor education delivers transformative
experiences that foster personal and educational growth
Evaluating Perceptions of the Effectiveness of Dog-Assisted Therapy for Reducing Challenging Behaviours Demonstrated by Children with Neurodevelopmental Disorders
Full text linkCanine-assisted therapy, also known as dog-assisted therapy (DAT) is a type of animal-assisted therapy that uses dogs (Canis lupus familiaris) to help people improve their mental and physical well-being. Although there is only emerging evidence for the effectiveness of DAT, it is possible that DAT may support children with neurodevelopmental disorders (NDD) with managing challenging behaviours such as aggression, self-injurious behaviours, and property destruction. The purpose of this study is to assess perceptions of DAT in reducing challenging behaviours through an online survey while exploring the potential utility of this approach. Across different groups of individuals (e.g., caregivers, clinical professionals), views of DAT varied with some groups showing interest and others indicating that DAT could be effective at reducing challenging behaviours. However, a number of potential stakeholder-specific barriers were identified that should be addressed before an experimental investigation of DAT is conducted. The findings from this study explores how stakeholders view DAT and provides avenues for future research, including what should be considered in future empirical research, and developing interventions that are practical.
Keywords: challenging behaviours, dog-assisted therapy, therapy dog, surve
Nonlinear Wave Equation for an Elastic String: Derivation, Symmetries, and Conserved Quantities
Full text linkThe goal of this thesis is to study the exact, most general wave equation governing the large-amplitude motion of an elastic string. The linear one-dimensional wave equation, commonly presented in undergraduate textbooks to describe the motion of an elastic string, relies on simplifying assumptions such as Hooke's law, all of which fail for large-amplitude motion.
We examine these assumptions and offer a brief survey of derivations in the literature that relax some of these assumptions while retaining Hooke's law. We then present two derivations of the exact wave equation from nonlinear elasticity and continuum mechanics, both consistent with each other, to describe large amplitude motion.
Finally, we turn to symmetries and conservation laws, two important tools in the study of partial differential equations. We find and interpret the kinematic symmetries and conservation laws admitted by this wave equation. The conservation laws are obtained from the symmetries by applying Noether's theorem. We describe the theory behind both computations and perform them using Maple software
Increased social reward behavior in adolescent male and female rats prenatally exposed to alcohol is associated with altered dopamine receptor expression
No full textPrenatal alcohol exposure (PAE) has detrimental consequences on cognitive, physiological, and social development. Adolescence, characterized by increased exploration, risk-taking, and social interaction, is a critical developmental stage that may amplify social deficits caused by PAE. I examined how PAE affects social reward behaviour across sex and developmental stages using a social reward task to measure preferences for social, non-social, and neutral stimuli at postnatal day (P)30, P40, P50, and P70. PAE rats exhibited greater social preference than controls during training sessions. On a progressive ratio test, PAE rats also had a greater social preference compared to controls. Extinction testing showed PAE males persisted in responding to the previously social side, resisting the control typical shift to a non-social preference. Dopamine receptor Western Bolt analysis revealed sex- and age-specific effects. Both PAE males and females showed increased D2 receptor expression in the nucleus accumbens at P30 and P50. In contrast, D3 receptor expression was decreased in the nucleus accumbens of P30 PAE males. In the medial amygdala, PAE females exhibited reduced D3 expression at P40 and P70, while PAE males showed similar reductions at P30 and P50. These findings suggest that PAE disrupts the development of social motivation and dopamine receptor expression, with distinct effects based on sex and developmental stage. The observed increases in D2 expression, coupled with decreases in the inhibitory D3 receptor, may contribute to the heightened social motivation in PAE rats by shifting the balance of dopamine signaling toward increased reward sensitivity and reduced behavioural inhibition
Walter Lewis stereocards collection, 1904-1913, n.d.
Full text linkThe collection consists of 12 stereocards. Six of the stereocards feature photographs of Port Robinson and the Welland Canal. Images include construction of the new Welland Ship Canal; a ship in the canal; a boat in one of the 25 locks of the new Welland Canal near Thorold; J.A. Cowan with his wife and daughter outside of a home on South and Margaret Streets in Port Robinson (1913); J.A. Cowan and his wife and daughter sitting underneath a tree in Port Robinson (1913); and the exterior of the Standard Steel Construction Co. Shop in Port Robinson.
The other six stereocards feature photographs of St. Catharines and Decew. Images include the back of St. Paul Street in St. Catharines, looking up from the Welland Canal; a street view in St. Catharines; Decew Falls; the water below the cascade at Decew Falls; a man standing in front of Decew Falls; and a monument or grave
Smart or Shallow? Postplagiarism, Trust, and the Future of Learning with GenAI
Full text linkThis presentation examines how generative AI challenges education in the postplagiarism era. It explores whether AI functions as a complementary or competitive artifact, highlights the role of cognitive and affective trust, and considers the pedagogical practices needed to guide learners toward responsible and meaningful use of AI.This presentation examines the role of GenAI in the postplagiarism era, where the challenge is no longer whether AI should be used but how it shapes learning. Drawing on Eaton’s (2023) framework of postplagiarism, Krakauer’s distinction between complementary and competitive cognitive artifacts, and Mayer et al.’s (1995) model of trust, the talk explores student perspectives on AI use, the asymmetries of trust between students, educators, and employers, and the risks of over-reliance. The implications highlight a shift toward the responsible integration of AI, urging educators to design practices where AI complements human intelligence rather than competes with it.CAIELI, University of Calgary
High-Order Graph Neural Networks and Contrastive Meta-Learning for Few-Shot Node Classification
Full text linkGraph neural networks (GNNs) have shown significant progress in node classification
tasks. However, their performance declines when learning from only a few examples
per class or when adapting to unseen classes. Meta-learning helps overcome this
limitation by enabling models to generalize from limited examples, and adapt to
novel classes not encountered during training. In this setting, algorithms train on
diverse meta-tasks consisting of a support set containing a few nodes from specific
classes and a query set with unseen nodes from those classes, which is used to evaluate
their performance based on their ability to adapt to novel data distributions. Current
approaches often augment meta-tasks with additional data such as the neighboring
nodes of target nodes are used to enrich both support and query sets. However,
the structural complexity of graphs introduces challenges in designing effective metatasks,
as variations in graph structures across tasks can hinder consistent feature
representations. To address these challenges, this thesis explores two new approaches:
(1) augmentation strategies in combination with contrastive learning to extract node
and class characteristics by identifying instances based on similarity and (2) highorder
GNNs for enhanced expressiveness of the models. We evaluate the effectiveness
of the proposed approaches through a comprehensive comparison with state-of-the-art
methods on benchmark node classification datasets
Optimal and Robust Designs of Progressive Stress Loading Accelerated Life Tests under Progressive Type II Censoring
Full text linkIn traditional life testing experiments, it is often difficult to observe failures in highly reliable products due to their long lifespans, especially under normal operating conditions. Accelerated life tests (ALT) is a widely used strategy to obtain sufficient failure data within a shorter period. This project focuses on developing optimal and robust designs for ALT using progressive stress loading plans under progressive Type-II censoring. The underlying lifetime distributions are assumed to be either exponential or Weibull. Optimal designs are derived based on three different criteria: c*-optimality, D-optimality, and A-optimality. The resulting designs demonstrate high efficiency. However, these optimal designs are only locally optimal, as they depend on unknown parameters that must be estimated. To address this uncertainty, we adopt a minimax approach to identify robust stress loading rates that minimize the maximum potential loss. The resulting minimax designs are shown to be robust over a plausible range of parameter values
Exploring Computational Thinking and Mathematical Reasoning Through Programming-Based Mathematics Tasks in Scratch and Python
Full text linkThis exploratory study seeks to better understand computational thinking (CT), mathematical reasoning (MR), and their interplay in solving programming-based mathematical tasks at the secondary level. Theoretically, I mainly adopt Kallia et al.’s (2021) characterization of CT for mathematics education and Jeannotte and Kieran’s (2017) model of MR. Empirically, I reflect on my engagement with three mathematical tasks drawn from Gadanidis’ (2022) Math + Coding Teams, using Scratch and Python. The analysis consists of identifying CT components (e.g., abstraction, decomposition, algorithmic thinking) and MR processes (e.g., conjecturing, generalizing, justifying), and their interaction. My analysis suggests that CT, through coding, supported my problem-solving and enabled hypothesis testing and iterative MR refinement. In other words, the programming environments served not only as execution tools but as spaces for mathematics inquiry and exploration, enhancing both my CT and MR engagement. These findings highlight the value of integrating coding into mathematics education to foster conceptual reasoning.
Keywords: Computational Thinking, Mathematical Reasoning, Programming-Based Tasks, Mathematics Education, Scratch and Python