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Open Access
Indigenous instructors’ perspectives on pre-service teacher education: Poetic responses to “difficult” learning and teaching
(Race Ethnicity and Education, 2020-01-27) Poitras Pratt, Yvonne; Hanson, Aubrey Jean
Instructors teaching an Indigenous education course face the challenges of shifting students’ understanding and inviting them into the work of decolonizing education. Indigenous instructors take on the embodied and emotional work of highlighting diverse representations of Indigenous peoples, histories, and perspectives in scholarship in order to make this learning meaningful to students. Bringing such views to education students, who are mostly non-Indigenous, is no easy task. In this study, we examine instructor experiences of difficult teaching within a mandatory Indigenous education course in Canada. We adopt a ‘poetics of anti-racism’ to represent and explore the moments of difficult teaching that are indicated by what is said, and unsaid, by the Indigenous instructors we interviewed. We argue that poetic approaches are powerful in articulating the complexity of Indigenous instructors’ experiences, as well as inspiring moments of transformation in education.
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Open Access
Experiencing the shift: How postsecondary contract and continuing faculty moved to online course delivery
(Brock University, 2021-07-13) Danyluk, Patricia; Burns, Amy
The shift to online learning that occurred in March of 2020 created an unprecedented period of intense work for faculty and sessional instructors at the postsecondary level. This shift necessitated courses be adapted under short timelines, new technology be integrated into course design, and teaching strategies and assessment methods be adapted for an online environment (Van Nuland et al., 2020). This study examines how sessional instructors, referred to in this article as contract faculty, and continuing full-time faculty members delivering the same online courses experienced this shift. While the demands of a continuing faculty position call for balancing of teaching, research, and service responsibilities, contract instructors have their own unique stressors (Karram Stephenson et al., 2020). Contract faculty lack job security, are paid by the course, and often receive their teaching assignments with short notice. By examining their perspectives on delivering the same courses online, we learn that the shift to online teaching resulted in additional work in order to adapt courses to the online environment, with faculty describing the challenges of balancing the additional work with other responsibilities of their position. Concerns of participants focused on a perceived inability to develop relationships with students in an online environment.
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Open Access
Unexpected Field-Aligned Structure in Equatorial Plasma Bubbles
(2024-07-10) Beyene, Bizuayehu Addisie; Knudsen, David; Skone, Susan; Brown, Jo-Anne Catherine; Ouyed, Rachid; Plume, Rene
Equatorial plasma bubbles, commonly known as EPBs, are field-aligned ionospheric irregularities in the bottomside of the F-region equatorial ionosphere generated due to the RayleighTaylor instability. EPBs affect radio waves and are sources of error for Global Navigation Satellite Systems (GNSS) due to their effect on the amplitude and phase of the satellite signal. In this thesis, 2 Hz plasma density data from 2014 to 2023 from the Swarm satellite mission orbiting nearly parallel to geomagnetic field lines is used to study equatorial plasma bubble characteristics such as bubble length and occurrence frequency. A moving average iterative smoothing technique over different window sizes was used to extract the smoothed background data, which in turn was used to compute the relative plasma density that is used to identify bubble boundaries based on a predefined threshold value. The results are compared with data from the Communications/Navigation Outage Forecasting System (C/NOFS) satellite, which cut across bubbles while flying eastward. According to the results obtained, plasma bubbles appear after sunset until before dawn which is in agreement with previous results and the existing theory. Although it is commonly believed that EPBs extend along the entire geomagnetic field line, the results in this study show similar degrees of structure in both Swarm and C/NOFS data, despite their orthogonal directions of travel. This suggests a much higher degree of structuring along B than previously recognized and strongly suggests a heretofore unidentified source of severe plasma structure parallel to B.
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Open Access
Microbial dysbiosis alters serotonin signalling in a post-inflammatory murine model of visceral pain
(2024-07-10) Roth, Timothy Douglas; Sharkey, Keith; Nasser, Yasmin; Altier, Christophe
Inflammatory bowel disease (IBD) is a chronic disorder characterized by inflammation of the gastrointestinal tract, affecting a growing number of individuals worldwide. Despite achieving endoscopic remission, many IBD patients continue to experience visceral pain, suggesting underlying mechanisms beyond inflammation. One hypothesis implicates alterations in gut microbiota post-inflammation, leading to dysregulated serotonin (5-HT) signalling within the gut and heightened pain sensitivity. This thesis investigated this hypothesis using a mouse model of IBD in remission associated with visceral pain to explore changes in enterochromaffin cell populations, gene expression related to 5-HT synthesis, transport, and degradation, as well as 5-HT concentration and its metabolites. Additionally, fecal microbiota transplant (FMT) experiments were performed using stool from DSS-treated mice, alongside comparative analyses with germ-free (GF) mice, to delineate the impact of the microbiota on post-inflammatory pain in IBD and establish a baseline for gut microbiota effects on 5-HT signalling. High-performance liquid chromatography (HPLC) was utilized to assess 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) tissue concentrations, and enzyme-linked immunosorbent assay (ELISA) was employed to determine 5-HT release dynamics in the gut. Our findings revealed region-specific differences in 5-HT release in the terminal ileum, proximal colon, and distal colon, suggesting localized alterations in 5-HT signalling post-inflammation. Additionally, GF mice displayed distinct patterns of altered gene expression and 5-HT/5-HIAA concentration compared to conventionally colonized counterparts, underscoring the pivotal role of gut microbiota in modulating 5-HT metabolism and signalling. FMT experiments allowed us to assess the impact of dysbiotic microbiota on post-inflammatory pain. Surprisingly, we found no significant differences in gene expression between control and DSS-treated FMT groups, suggesting resilience of the host to changes in microbiota composition. However, we observed differences in 5-HT release dynamics between FMT groups, indicating potential microbiota-driven alterations in neuronal signalling pathways. Overall, we found alterations in 5-HT signalling in the recovery model of DSS-induced colitis. These findings enhance our understanding of the pathophysiology of IBD-related pain, highlighting the complex interplay between gut microbiota and 5-HT signalling after a period of intestinal inflammation.
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Open Access
Tuning the Van Der Waals Forces between Cations and Proteins in Polarizable and Non-polarizable Force Fields
(2024-07-08) Amin, Kazi Shudipto; Tieleman, Peter DP; Salahub, Dennis R; MacCallum, Justin Laine; Ng, Kenneth Kai-Sing; Kusalik, Peter G; Rowley, Christopher
Molecular dynamics (MD) is a set of computational methods widely used in various disciplines to simulate the motion of various molecular structures. In this work, MD refers particularly to their application to the study of biomolecular systems like proteins. Despite constant refinement and progress, there remain shortcomings in the ability of MD in several cases, such as in accurately capturing the interactions between metals and proteins. This work evaluates some widely used molecular dynamics force-fields such as CHARMM and OPLS-AA. Evaluations are also performed on existing extensions of these force-fields that include polarization or charge transfer effects, which are known to be crucial to metal-protein interactions. Preliminary studies show that while polarizable force-fields may better reproduce some QM energies of representative molecules in vacuum, there still remains a need to further optimize them, particularly the van der Waals interactions described by the Lennard-Jones potential, which is challenging due to the additional parameters involved. This is evident from the benchmarking study performed with Ca2+, with calmodulin as the protein used for experimental verification. A follow-up study implements a charge transfer and polarization (CTPOL) extension of OPLS-AA for a specific Zn-finger system and evaluates the extension with a variety of coordination metrics extracted from experimental data. The results show significant improvement over the original OPLS-AA, particularly when the Lennard-Jones parameters are re-optimized, with some caveats which are discussed in the study. The Drude polarizable force-field, which extends CHARMM by adding Drude particles to capture atomic polarization, is evaluated against osmotic pressure data for monovalent cations in acetate solutions, representing M+COO- interactions common in proteins with a number of exposed ASP and GLU residues. Quantum mechanical (QM) data of acetate-M+ in vacuum in various conformations is used as a reference to perform optimization of the Lennard-Jones and Coulomb screening parameters of specific cation-oxygen pairs in the Drude polarizable force-field. Different criteria are explored to perform these optimizations, with interestingly very different results. The most effective predictor of osmotic pressure is a criterion that compares local variations, or “shape” of energy minima rather than absolute differences. This criterion provides parameters that reproduce experimental osmotic pressure quite accurately for a full range of concentrations and three different ions (K+, Li+, Na+), without the need for further refinement. Future direction for parametrization in general is suggested, which includes exploring objective functions as a high priority, as well as deviating from the standard Lennard-Jones potential as a representation of van der Waals forces.