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The effects of activation history on neuromuscular responses
No full textThe thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, "Thesis title." (Year). Western University Open Repository. https://doi.org/10.71858/123456. Muscle contractility is influenced by its activation history. For example, prolonged muscle activation (e.g., minutes) reduces force; termed muscle fatigue. Conversely, brief (e.g., seconds) activation enhances submaximal force; termed post-activation potentiation (PAP). Prior muscle activation is required for both effects and thus there is a coexistence between these processes. Here, fatigue and PAP were investigated independently, and concurrently in humans by using voluntary and electrically stimulated isometric (study two) and dynamic contractions (studies one & four), and with single motor unit recordings using intramuscular electromyography (studies two & four). For study three, isolated intact single myofibers from mice were used to make assessments of force changes and intracellular calcium transients. Study one demonstrated that during voluntary fatiguing contractions, PAP mechanisms delayed power loss in response to stimulated low frequencies of muscle excitation (submaximal) despite a decline in stimulated high frequencies of excitation (maximal). During recovery, power in response to stimulated low frequencies was preferentially impaired. However, inducing PAP ameliorated this power loss. Therefore, the concurrent effects of fatigue and PAP are frequency-dependent, and PAP mitigates power loss of low frequencies during recovery. Study two investigated the effect of PAP during recovery from fatigue on motor unit (MU) firing rates. During recovery, MU firing rates increased as submaximal torque generation was impaired compared to baseline. However, inducing PAP during the recovery state mitigated the requirement of higher MU firing rates. Therefore, firing rates are responsive to opposing influences on the contractile state and can make compensatory rate adjustments dependent on the active state of the muscle. Study three, in single myofibers, showed the preferential force loss of low frequencies of excitation (submaximal) during recovery was due to reduced cytosolic Ca2+. However, inducing post-tetanic potentiation in this state recovered submaximal force by increasing cytosolic Ca2+. Therefore, adjustments in force due to activation history are principally accomplished by opposing adjustments in cytosolic Ca2+. Study four demonstrated that compared to baseline inducing PAP increased MU recruitment thresholds, but decreased firing rates during contractions at 50 and 75% peak power. Therefore, MUs make compensatory adjustments in relation to the active state of the muscle during tasks requiring a high-power output
A Performer’s Approach to Two Violin Works by Nikos Skalkottas
No full textThe composer and violinist Nikos Skalkottas always fascinated me. An artist with a difficult path and fate, whose career started off brilliantly in interwar Berlin and was ruined by the rise of the Nazis to power and the following World War. Skalkottas was forced by the circumstances to return to his native Greece, where he remained unrecognized and unjustly neglected. Recognition and appreciation of his output came decades after his death. Despite all difficulties, he remained true to his artistic vision offering an example of dedication, resilience, and faith.
One of my first experiences with a piece composed in a more modern idiom was Skalkottas’s Sonata for Violin Solo. It opened for me the way to the works of significant innovator composers of the first half of the twentieth century such as Arnold Schoenberg and Bela Bartok. Although the Sonata is a highly organized composition, tightly and logically written, it has a strong sensitive, expressive, lyrical, “romantic” essence.
My desire to better understand and delve deeper into Skalkottas’s world motivated me to undertake this research paper. In the paper I focus on two violin works, the Sonata for Violin Solo composed in 1925, and the Little Suite No. 2 for Violin and Piano, composed in 1949.
The paper is organized into four chapters and an appendix. The first chapter is a biographical sketch, the second chapter offers an analysis of the Sonata for Violin Solo, the third chapter presents an analysis of the Little Suite No. 2 for Violin and Piano, and the fourth chapter is a discussion of Skalkottas’s approach to violin playing based on his unpublished essay “On Violin Technique,” and on examples from the two works discussed in the paper. In the appendix I include an English translation of Skalkottas’s essay “On Violin Technique.”
My aim was to give a performer’s perspective on the two works, the way a violinist would approach them while studying them and preparing them for a performance. My attempt was to present the material employed in the two works, to show the way this material is organized, and offer my understanding on how this material conveys the concept and the idea of the two compositions. I hope the paper will ignite the interest of other violinists in these two compositions, prompting them to develop their own perspectives and interpretations of these works
Neuroregulation in Virtual Reality
No full textNeuroregulation (NR) and Virtual Reality (VR) have demonstrated effectiveness in supporting mental health and wellbeing. This thesis explored the psychological (self-reported emotion) and physiological (electroencephalography [EEG] and electrocardiography [ECG]) outcomes of EEG-alpha NR in both two-dimensional (2D) and three-dimensional (VR) viewing formats. Participants were randomized to either up-regulate (alpha-up) or down-regulate (alpha-down) their EEG alpha power with results indicating that participants successfully modulated their EEG alpha in the targeted direction. Moreover, changes in amplitude and coherence of EEG alpha and other frequency bands occurred depending on training direction (alpha-up vs -down) and viewing format (VR vs 2D), although no differences were seen for ECG outcomes. Participants also reported greater positive affect during NR in VR compared to NR in the 2D format. Based on the results, interpretations and recommendations are made for further clinical and research applications.Nadine Charania, 202
Reactionary Impotence: Jordan Peterson, Trump, and the Ideology of Decline
No full textThe thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, "Thesis title." (Year). Western University Open Repository. https://doi.org/10.71858/123456. This thesis identifies two complementary tendencies of the right wing. The first is the loud, proud, and aggressive reactionary politics of Donald Trump; the second is its seeming opposite, the introspective, self-critical, therapeutic program of Jordan Peterson. Where Trump emphasizes external action and political agitation, Peterson emphasizes internal reflection and political withdrawal. To that end, this thesis charts Peterson’s calculated rise to fame via his exploitation of social media, and the subsequent success of his didactic 2018 tome 12 Rules for Life; it draws from memetics, Marxist theory, and psychoanalysis to interpret him as uniquely successful in speaking to the collective insecurities of a generation of young men, who sympathize with right-wing politics even as they recognize its inability to improve the sociopolitical conditions under which they live. It analyzes Peterson’s honing of his own brand of anti-communist, anti-ideological, and anti-rational thought from his early years of obscurity to his flourishing as a public intellectual in the late 2010s. His dispositions lead him to familiarly right-wing opposition to novelty, feminism, and trans people; however, unlike Trump, who emphasizes masculine aggression and political engagement, Peterson adopts an aesthetic of meekness, of despair, of pre-emptive defeat. He does not expect that the right’s political program will succeed, and exhorts his audience not to try. In contrast to the neverending rally of MAGA Trumpism, Petersonian thought renounces political agitation as a route to happiness, and promotes focus on self-improvement instead. It accepts misery and hardship as a universal constant, telling adherents to refrain from attempting to change the world, lest they make it even worse. In this philosophy, neither America, nor the world, can be made great again, as they can under Trumpism; on the contrary, the apocalypse is unavoidable. In short, the Peterson movement is simultaneously reactionary and impotent
"The Gilt-Edged Class": American and Canadian Telegraphers' Bodies and Work
No full textThe thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, "Thesis title." (Year). Western University Open Repository. https://doi.org/10.71858/123456. This dissertation examines the lives and work of American and Canadian telegraph operators from 1870 to 1929. While historians have studied the telegraph as a technology and a business, few have integrated telegraphy with histories of class, gender, or the human body. Integrating the bodily turn means recognizing the physicality of telegraph work. This dissertation centres the bodies of telegraph operators and seeks to contextualize those bodies within the larger technological and corporate systems in which they were embedded. Operators’ class identities have often been ambiguous or misunderstood. I argue that telegraph work was real, physical work, in a way that has too often been elided, and that it is important to see operators as part of the working class. Ultimately, this dissertation demonstrates the ways in which human bodies and human labour can be erased within large technological networks. I explore the historical significance of that erasure and its relevance for understanding the precarity of labour in high-tech industries today
In Situ Nanoindentation and Crystal Plasticity Modeling of Zirconium Alloys and Hydrides
No full textZirconium alloys are important nuclear materials used in the core of CANada Deuterium Uranium (CANDU) nuclear reactors due to their low neutron absorption and good mechanical properties. However, long-term service leads to hydrogen ingress and precipitation of brittle zirconium hydride phases, which can severely embrittle the material. This thesis investigates the local mechanical behavior of hydrided zirconium alloys using advanced experimental and modeling techniques. In situ nanoindentation inside a scanning electron microscope (SEM) was combined with electron backscatter diffraction (EBSD) to measure hardness and deformation in specific regions, including δ-hydride precipitates and the surrounding α-zirconium matrix. Complementary crystal plasticity finite element (CPFE) simulations were developed to model the indentation response and to elucidate deformation mechanisms. The results show that δ-hydride phases exhibit significantly higher hardness compared to the Zr matrix, leading to localized stress and strain fields. Indentation-induced deformation was found to concentrate at hydride tips and matrix–hydride interfaces. The presence of a second-phase β-Zr, in Zr-2.5Nb alloy, influences the local stress distribution and provides additional deformation pathways, moderating the constraint effect of hydrides. The CPFE model successfully captured the load–displacement behavior and revealed that hydride-induced transformation strains strongly affect local plasticity. This work provides new insight into how hydrides and microstructure jointly affect localized mechanical properties.Khaled El-sobahi, 202
Peace, Agroecology & Gastronomy: A case study on how Colombia can build a sustainable future
No full textThis dissertation explores alternative pathways for post-conflict reconstruction in Colombia by examining how locally grounded practices—specifically agroecology and gastronomy—can enhance peacebuilding processes. Framed within the broader literature on transitional justice, everyday peace, and ecological peacebuilding, the research responds to the central question: How can agroecology and gastronomy function as mechanisms for peacebuilding? Anchored in grassroots perspectives, the study demonstrates how food systems can generate enabling conditions for sustainable development and peace, while identifying the conditions required for them to equitably benefit all stakeholders. It further examines how this connection is
strengthened through a gendered lens that enhances resilience to climate-related shocks. Finally, it analyzes how organic, trust-based alliances among citizens foster civic trust and recognition, contributing to the repair of the social fabric in post-conflict settings. Fieldwork was conducted in both rural and urban contexts in Colombia. First, semi-structured interviews were carried out with internationally acclaimed chefs, researchers, and public sector
actors. Then, further research was conducted with ASOCOMAN, a campesino association in Montes de María, which transitioned from monoculture farming to agroecological production and has since emerged as a key supplier to some of the country’s top restaurants. Data was analyzed through a mixed-methods approach combining traditional qualitative techniques with Natural Language Processing (NLP). The findings offer insights into how recognizing the value of marginalized communities’ work enhances their self-perception and fosters more horizontal, reciprocal interactions among citizens. These dynamics enable the collective stewardship of cultural and natural resources toward a more inclusive and sustainable future. In deeply divided societies like Colombia, such exchanges serve as powerful entry points for reimagining shared common ground. This research proposes a framework for NGOs, international organizations, and policymakers to integrate gastronomy and agroecology as combined tools for conflict transformation, sustainable livelihoods, and inclusive peacebuilding.María Paula Espejo-Duarte, 202
Real solution of DAE and PDAE System
No full textGeneral systems of differential equations don't have restrictions on the number or type of equations. For example, they can be over or under-determined, and also contain algebraic constraints (e.g. algebraic equations such as in Differential-Algebraic equations (DAE) and Partial differential algebraic equations (PDAE). Increasingly such general systems arise from mathematical modeling of engineering and science problems such as in multibody mechanics, electrical circuit design, optimal control, chemical kinetics and chemical control systems. In most applications, only real solutions are of interest, rather than complex-valued solutions. Much progress has been made in exact differential elimination methods, which enable characterization of all hidden constraints of such general systems, by differentiating them until missing constraints are obtained by elimination. A major problem in these approaches is related to the exploding size of the differentiated systems. Due to the importance of these problems, we outline a Symbolic-Numeric Method to find at least one real point on each connected component of the solutions set of such systems
Assessing Salmonid Foraging Ecology in Lake Huron Using Dietary Analyses
No full textThe Lake Huron fish community consists of many non-native species, including the introduced piscivorous Pacific salmonids chinook salmon Oncorhynchus tshawtscha, coho salmon Oncorhynchus kisutch, and rainbow trout Oncorhynchus mykiss. The only abundant native piscivorous salmonid is the lake trout Salvelinus namaycush. Since 1980, there has been a steady decline in the biomass of the prey fishes these salmonids consume. The collapse of alewife Alosa pseudoharengus in 2003 has led to growing concern that lake trout will be outcompeted by the non-native salmonids. Paramount to understanding this concern is determining the diet overlap between salmonids and how the overlap has shifted with changes in prey abundance. Here, stable isotope analyses, visual identification of gut contents, and gut content eDNA metabarcoding revealed large percentages of lake-wide overlap among all piscivorous salmonids. Given the competitiveness of the Pacific salmonids, this is concerning for the re-establishment of the native lake trout.Jacob Lasci 202
Contralateral Lateral Extra-articular Tenodesis to Prevent Contralateral Anterior Cruciate Ligament Rupture
No full textAnterior cruciate ligament (ACL) reconstruction is a widely performed orthopaedic procedure, yet patients remain at risk of ipsilateral graft failure and contralateral ACL rupture. This thesis explores the concept of prophylactic contralateral lateral extra-articular tenodesis (LET), a novel, controversial approach intended to prevent contralateral ACL injury at the time of primary ACL reconstruction. Three complementary studies were undertaken: (1) a systematic review evaluating strategies for preventing repeat ACL injury; (2) a cadaveric biomechanical study comparing the effect of two LET techniques on the native intact ACL; and (3) an international survey assessing orthopaedic surgeons’ views on contralateral LET. Together, these studies synthesize existing evidence, establish a biomechanical rationale, and gauge clinical receptiveness to this preventive concept. While further research is needed, including ongoing studies assessing contralateral ACL tear risk and patient perspectives, this work offers a multidisciplinary, proof-of-concept foundation for the potential role of contralateral LET in ACL injury prevention