No description available.

No description available.

Animals who live in the high-altitude environment are faced with the harsh conditions of low oxygen availability. This can make it difficult to perform daily tasks that require aerobic metabolism. However, deer mice (Peromyscus maniculatus) have evolved physiological adaptions that allow populations to survive in the high-altitude environment. One activity important for survival is aerobic locomotion and the rapid recovery of muscle metabolism after a bout of exercise. Hypoxia acclimated high-altitude mice have a greater reliance on carbohydrates to power exercise than low altitude mice and show a significant depletion of muscle glycogen. However, it is unclear how quickly after exercise is finished that these mice can replenish muscle glycogen stores. The gastrocnemius muscle of high-altitude deer mice has a more aerobic phenotype and a greater capacity to oxidize lipids than in low altitude mice. This suggests that high altitude mice may recover more quickly from exercise than their lowland counterparts due to a greater capacity to power glycogen replenishment through aerobic metabolism using the lipids stored in muscle as intramuscular triglycerides (IMTG). Using low- and high-altitude native deer mice born and raised in common lab conditions and acclimated to chronic hypoxia, I determined changes in oxygen consumption (VO2) following aerobic exercise and sampled skeletal muscle at various time points during recovery to examine changes in key metabolites, including glycogen and IMTG. I found there was depletion in glycogen stores during exercise in lowlanders and glycogen did return to resting levels following 90 minutes of recovery. In contrast, IMTG’s did not significantly change with exercise or during the recovery period in either population. These data suggest that muscle recovery from aerobic exercise may be influenced by altitude ancestry in deer mice. / Thesis / Master of Science (MSc)

Thesis (Ed.D.)—Boston University

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No description available.

High manganese steels offer an outstanding combination of high strength and ductility owing to their high sustained strain hardening rates. The strain-induced deformation products in these steels (mechanical twins and ε-martensite) increase the work hardening rates by acting as barriers for dislocation motion. A significant determinant of the deformation products in these steels is the value of stacking fault energy (SFE), which is in turn strongly dependent on the alloy manganese and carbon contents. The main objective of present work is to investigate the microstructural evolution and mechanical behaviour of both homogenous and compositionally graded high-Mn steels, where C compositional gradients were introduced into the latter. The starting materials in this work were cold rolled Fe-22Mn-0.6C and Fe-30Mn-0.6C steels. For both starting alloys, decarburization and annealing heat-treatments were used to obtain four homogenous alloys with carbon contents of approximately 0, 0.2, 0.4 and 0.6 wt. % with similar grain sizes. Decarburization heat treatments were also applied to obtain three carbon graded Fe-22Mn-C alloys (G1, G2, G3) and one carbon graded Fe-30Mn-C alloy. Microstructural observations determined the deformation products to be mechanical ε-martensite for the 22Mn-0C and 22Mn-0.2C alloys and mechanical twins for the 22Mn-0.6C, 30Mn-0.2C, 30Mn-0.4C and 30Mn-0.6C alloys. For the 22Mn-0.4C and 30Mn-0C alloys, both mechanical twins and ε-martensite were observed during deformation. For all the carbon graded Fe-22Mn-C alloys, the dominant deformation products changed from mechanical ε-martensite at the near-surface layer to a mixture of mechanical twins and ε-martensite or mechanical twins only at the inner cross-section layers. In the case of carbon graded Fe-30Mn-C alloy, the deformation products altered from a combination of mechanical ε-martensite and twins at the near-surface layer to mechanical twins at the inner cross-section layers. For all the homogenous alloys, the ultimate tensile strength and uniform elongation increased with increasing alloy carbon content. The work hardening behaviour of these steels was successfully modelled using a modified Kocks-Mecking model, in which the work hardening was the sum of the dislocation glide contribution and the phase transition contribution – mechanical twinning and/or mechanical ε-martensite formation – as dictated by the formation kinetics of both deformation products. For both alloy systems, the mechanical properties of the carbon graded alloys were not as good as the monolithic 22Mn-0.6C and 30Mn-0.6C alloys due to their lower sustained high work hardening rates. Both the mechanical ε-martensite and twin formation were found to follow a sigmoidal kinetic with strain. In the case of twin formation homogenous alloys, the saturated volume fraction of twins was directly proportional to the alloy SFE. For the ε-martensite formation homogenous alloys, the ε-martensite volume fraction at fracture was found to be strongly dependent on alloy SFE, where it declined sigmoidally with increasing alloy SFE. It was also found that the ε-martensite volume fraction at fracture – approximately 0.7 – was independent of SFE for SFE  6 mJ/m2. This indicated that the critical damage mechanism was determined by the kinetics of the ε-martensite formation, which was in turn dictated by the alloy SFE. Finally, it was found that the stress for the onset of mechanical twinning – and consequent increase in the work hardening rate – for the higher SFE, twinning dominated alloys was linearly proportional to the alloy SFE. / Thesis / Doctor of Philosophy (PhD)

Thesis (Ed.D.)--Boston University.

Inclusive education involves the participation of all children, including those with disabilities, as an expectation within mainstream education. The goal of inclusive education in Ontario, Canada is for all students, regardless of differences, to have equitable access to curriculum instruction with their typically developing peers. Physical education (PE) involves curriculum delivery in unique settings. While inclusive practice in PE has been studied in elementary schools, less research has focused on secondary school. In this dissertation, I explore how curriculum, resources, and educational practices support or create barriers for provision of inclusive PE in secondary schools. The first manuscript describes a critical discourse analysis of the 2015 Ontario Physical Education Curriculum, Grades 9-12. Analysis considers how language is used and reflected within curricular text to represent inclusion. The analysis highlights that teachers require support beyond policy to practice inclusion, and advocates for teacher and student voices to be represented in curricular documents. The second manuscript presents a rapid review of current literature to overview resources for Universal Design for Learning (UDL) available to support implementation in PE settings. Findings show that literature available to encourage professional development in universal design in PE is limited but growing. Physical educators still require support to facilitate implementation of UDL in practice. The third manuscript uses interpretive description to explore the perspectives of Ontario secondary school PE teachers implementing inclusive PE. Physical educators express a need for professional development opportunities and in-situ resources that provide informed knowledge about inclusive practices. The discussion chapter reflects on the exploratory findings of this research. Collaboration with school-based rehabilitation health professionals, such as occupational therapists and physical therapists, may provide a novel approach to support physical educators. Future research, policy, and practice initiatives should consider teacher agency within the context of system-based barriers that exist and influence inclusive PE. / Thesis / Candidate in Philosophy / Inclusive classrooms allow children with different abilities to learn together. Physical education (PE) is a class that may require adaptive teaching strategies and environmental modifications for all students to participate. This thesis explores how we can support PE teachers in delivering inclusive PE for secondary school students. The first study looks at how the Ontario Secondary School PE curriculum uses language to support inclusion. The second study identifies recent literature that explores how Universal Design for Learning, as a teaching approach, is used in PE classes to support inclusion. The third study examines physical educators’ views on what they need to create inclusive classes so that diverse students can participate fully. Findings from all studies suggest that PE teachers may benefit from collaboration with health professionals with expertise in development, movement science, and inclusion.

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