9441 research outputs found
Sort by
Combat Motivation and Swift Trust in Canada’s Battle of Hong Kong, 1941
Get PDFAbstract: In December 1941, the British Crown Colony of Hong Kong was the site of a doomed last stand, when the Imperial Japanese Army assaulted the British enclave near-simultaneously with the strike on Pearl Harbor. Among Hong Kong’s multinational defenders were two battalions of Canadian infantry, designated “C Force.” They held out for a significant period and inflicted heavy casualties upon the Japanese, despite the fact that the Canadians were under-trained, under-equipped and fighting a battle that could not be won. This article is the first major study of combat motivation in the Battle of Hong Kong, taking the Canadian C Force as a case study. It explores the training, morale, cohesion and behaviour of the Canadians who fought this hopeless battle. This article argues that the concept of “swift trust” cohesion can explain how the Canadians fought so well against impossible odds at Hong Kong, even when primary group cohesion became impossible to sustain during battle
Investigating the Thermal Stratification Patterns of a Shallow Polymictic Boreal Shield Lake and the Effectiveness of Models in Predicting Shallow Lake Thermal Profiles
Get PDFThermal stratification is a core process of lakes which plays a critical role in shaping the ecological dynamics of lakes, influencing major processes like nutrient cycling and oxygen availability. For shallow polymictic lakes, thermal stratification patterns present some unique differences due to the complex and variable nature of these lakes. In this thesis, I examined thermal stratification in a shallow polymictic lake in northwestern Ontario during the ice-free season of 2019 to investigate the frequency, duration, and driving factors of thermal stratification. The lake underwent 146 separate stratification events, with a median duration of 2 hours per event, with a total time spent stratified of almost one third the entire study period. The primary drivers of this thermal stratification were air temperature, wind direction, and wind speed, underscoring their significance in the thermal regime of the lake. Also observed was a brief period of hypolimnetic hypoxia prior to a phytoplankton bloom, highlighting potential influence from internal nutrient loading from sediment to have occurred under low redox conditions. Another aspect of this investigation involved the evaluation of five one-dimensional models on their performance in reproducing the observed thermal stratification patterns in both the shallow polymictic lake and an adjacent shallow dimictic lake. While some models demonstrated success in simulating thermal stratification, particularly in the dimictic lake, they struggled to accurately capture the dynamic patterns observed in the polymictic lake. The most effective model calculated only 55 stratification events compared to the 146 that were observed in Lake 303, suggesting the need for highly specific modeling approaches tailored to shallow polymictic lakes. These findings exhibit the complexity of thermal stratification dynamics in shallow polymictic lakes and highlight the importance for additional field observations as well as modeling efforts to enhance our understanding of this lake type. Improving the state of modeling for these lakes is essential for accurately representing the unique nature of shallow polymictic lakes, which is crucial for effective lake management and conservation strategies
Sustaining While Disrupting: The Challenge of Congregational Innovation
Get PDFReview of Sustaining While Disrupting: The Challenge of Congregational Innovation by F. Douglas Powe Jr. and Lovett H. Weems Jr. (Minneapolis: Fortress Press, 2022
Two Poems: White Sands and Superare
Get PDFLauren Camp recycles and resettles emotion in “White Sands” and “Superare.
Mining Waste in the Himalayas
Get PDFMateriality is a key aspect of the fourteen artworks I created over one month as Artist-in-Residence at Sagarmatha Next, the experience centre for sustainable tourism in the Khumbu region of Nepal. My intention with the residency is to create work from the human discards that accumulate in the area around Mount Everest, known as Sagarmatha in Nepali. The artwork I created during this residency are deeply rooted in the materiality of their components and serve as powerful commentaries on environmental issues, the passage of time, and the potential for transformation inherent in discarded materials. Through the deliberate use of waste, these pieces challenge viewers to reconsider their relationship with the environment and the concept of waste itself
Lichen it: Optimizing post-fire caribou lichen transplantation and assessment
No full textCaribou lichen species are common in mid- to late-seral boreal forests, serving as an important winter diet staple for boreal woodland caribou. However, as climate change causes boreal wildfires to increase in size, severity, and frequency, available tracts of mature forest are decreasing, diminishing the extent of mature caribou lichen stands. Caribou lichens reproduce vegetatively, so bigger and more severe fires could exacerbate their dispersal limitations, potentially extending the timeline for caribou lichen stand recovery beyond 80 years. Trials have shown that “transplanting” caribou lichen fragments into disturbed areas can lead to the establishment of caribou lichen mats; as such, caribou lichen transplantation (CLT) could accelerate the recovery of caribou lichen stands by compensating for their dispersal limitations. However, much remains ambiguous about the ideal transplantation locations in burned forests, as well as the best way to assess whether CLT has been successful. In my thesis, I evaluated the health and retention of caribou lichen fragments two years post-transplantation at 50 burned plots in the Dehcho region of Northwest Territories, Canada. My thesis had three objectives: 1) to identify the macro- and microenvironmental factors influencing CLT success, including the stand and fire history, the abiotic environment, resource competition, and interspecies associations; 2) to determine if three commonly used CLT success measures (fragment retention, chlorophyll fluorescence, and vigour) respond similarly to environmental conditions, and 3) to develop an accessible dichotomous key that resource management practitioners can use to identify optimal CLT locations in burns. My results showed that CLT is more successful in sunny, dry, and conifer-dominated burns and in burned peat bogs. They also point to vegetative species that were indicative of CLT success, such as Vaccinium vitis-ideae and Rhododendron groenlandicum. My results also showed that fragment retention, chlorophyll fluorescence, and vigour – three common measures of CLT success – were not strongly correlated, indicating that these methods capture different aspects of success and should not be used interchangeably. My results will help CLT practitioners identify optimal CLT locations in burns and to assess the outcomes effectively, improving CLT efficiency and offering new possibilities for boreal woodland caribou conservation efforts
Understanding Balance Control in Response to Gait Perturbations in Adults with Attention Deficit Hyperactivity Disorder
No full textIndividuals with attention deficit hyperactivity disorder (ADHD) are at higher risk of injury compared to neurotypical individuals. Additionally, children with ADHD become injured from falls with more frequency and severity, which may be an indication of balance dysfunction. Gait and standing studies done in children and adults with ADHD found higher variability in baseline walking parameters in children, as well as deficits in balance responses to perturbations and greater postural instability in children and adults. Additionally, this postural instability is associated with higher levels of regional cerebellar grey matter volume, and low neurotransmitter dopamine. There are currently no studies investigating balance during gait in adults with ADHD, even though falls frequently occur during walking within this group. The purpose of the current study was to understand the effects of ADHD on balance control in adults to inform the direction of future research. The aim was to investigate differences in balance responses between individuals with ADHD and those without during unexpected gait perturbations. It was hypothesized that adults with ADHD will exhibit impaired balance control, longer onset latency and greater muscle activation in comparison to control (non-ADHD). To test the hypotheses, twenty-two (22) participants (12 ADHD, 10 non-ADHD) were instructed to walk across an 8-meter walkway for 24 walking trials, 12 of which contained unexpected uneven walking surface perturbations in one of four directions (medial, lateral, anterior, posterior). The other 12 trials included random/no perturbations and were interspersed between to ensure unpredictability. Center of mass (COM), lateral base of support (BOS) and center of pressure (COP) was measured using force plate and kinematic data. Surface electromyography (EMG) was taken for four muscles of each leg (tibialis anterior, medial gastrocnemius, rectus femoris and medial hamstrings). The Adult ADHD Self Report Scale (ASRSv1.1) was also used to record ADHD symptom severity. Results showed that the ADHD group had a significantly higher COM-COP separation maximum in the anteroposterior direction (AP), a higher COM-BOS range, and a lower COM-BOS maximum and minimum in comparison to controls. There were no differences in the EMG measurements. This indicates adults with ADHD do exhibit balance deficits in comparison to adults without ADHD during both steady-state overground walking and in response to perturbations. Participants with ADHD also had more conservative balance responses when they encountered perturbations with greater threats to balance. In summary, this study demonstrates that ADHD is associated with balance control deficits in adults and provides insight on specific differences in stability during walking perturbations. These are findings that can be used to inform further areas of research in the topic
Characterization of cellulose O-acetyltransferases: Role in Biofilm Formation
No full textMost bacterial populations reside within biofilms, which are communities of microorganisms embedded in a self-produced polymer matrix. These biofilms play critical roles in colonization and persistence within targeted niches, often contributing to disease progression. Bacterial species under specific conditions produce and export polymers that undergo post-synthesis chemical modifications, such as acetylation or the addition of phosphoethanolamine, which influence the chemical properties of the polymer, biofilm structure, and organism persistence. While well-studied systems, such as the opportunistic pathogen Pseudomonas aeruginosa, demonstrate the role of acetylation in alginate biofilms and their contribution to colonization and persistence in cystic fibrosis lungs, the mechanisms behind similar modifications in Clostridioides difficile and related pathogenic Clostridia species remained largely uncharacterized. In addition, WssI and WssF, cellulose acetyltransferases from Pseudomonas fluorescens will be functionally characterized in tandem. This research identified and characterized the role of CdCcsI, an acetyltransferase encoded within the C. difficile cellulose synthase operon (ccs), in the acetylation of cellulose biofilms along with WssI and WssF from P. fluorescens. Kinetic and enzymatic assays confirmed that CdCcsI catalyzes acetyl transfer to cellulose substrates via a catalytic triad (Ser344, Asp196, and His198) and an oxyanion hole (Arg366, Tyr367). Chromosomal mutation studies demonstrated that loss of the catalytic residues significantly reduced acetylation activity and biofilm biomass by 71%, as confirmed by iii crystal violet assays and fluorescence microscopy. Inhibitor studies identified lead compounds that effectively reduced CdCcsI activity, highlighting potential targets for antibiofilm strategies. Structural studies, including CD spectroscopy, verified that enzymatic activity loss in the active site variants was due to the specific removal of catalytic residues and not misfolding, reinforcing the functional importance of CdCcsI in acetyl-cellulose biofilm production. This work provided novel insights into the molecular mechanisms of CdCcsI, emphasizing its critical role in biofilm formation and its potential as a target for disrupting pathogenic biofilms in Clostridia. These findings elucidate the mechanisms behind biofilm modification in Clostridia and pave the way for developing strategies to weaken the biofilm barrier, enhancing antimicrobial penetration and effectiveness against infections caused by C. difficile and other Clostridial pathogens
WHAT IS SUCCESS? HOW PEER SUPPORT WORKERS IN ONTARIO SEE ADDICTION & RECOVERY
Get PDFThe drug crisis in Canada has high mortality rates, especially in remote and rural communities, but there are significant barriers to accessing healthcare to which peer support may represent a partial solution, (Eddie et al., 2019; Englander et al., 2020; The Government of Canada, 2023; Kourgiantakis et al., 2023; Lavalley et al., 2020; Lennox et al., 202; Russell et al., 2021). Research how peer support workers define success in their work with adults experiencing addiction in Ontario, Canada is lacking, but important to understanding the crisis and implementing peer programs. Grounded in Marxist theory, the following exploratory research investigated the outcomes of interest to peer support workers, using data from 9 peer workers across rural, urban and remote Ontario. Thematic analysis produced 5 themes: i) “the professional is personal & the personal is professional”, “ii) Success is a blurry concept”, “iii) Recovery is more than abstinence”, iv) “Some barriers to peer work & recovery are institutional”, and v) “Some barriers to peer work & recovery are socially systemic”. The nature of peer work as the provision of unconditional support, not based on clinical outcomes, reveals a conflict between the peer workers and the larger healthcare system. The findings reflect both the psychological and material nature of addiction and the barriers to recovery, and are explained with concepts of alienation, reification, and capitalist oppression (Martin-Baro, 1994). Analyses of the addiction crisis in Ontario should take into account the historical and material sources of addiction. Social workers and clinicians should consider alternative models of support