The influence of skeletal muscle cell volume on carbohydrate metabolism in contracting skeletal muscle

This study investigated the regulation of carbohydrate metabolism through changes in skeletal muscle cell volume immediately post contraction and during recovery. Using an established in vitro isolated muscle strip model, soleus (SOL) and extensor digitorum longus (EDL) were dissected from male rats and incubated in an organ bath (perfused with 95% O2; 5% CO2, pH 7.4, temperature 25°C) containing medium- 199 altered to a target osmotic condition (iso-, hypo- or hyper-osmotic; 290, 1 80, 400 mmol/kg). Muscles were stimulated for 10 minutes (40 Hz SOL; 30 Hz EDL) and then either immediately flash frozen or allowed to recover for 20 minutes before subsequent metabolite and enzyme analysis. Results demonstrated a relative water decrease in HYPER vs. HYPOosmotic condition (n=8/group; p<0.05) regardless of muscle type. Specifically, the SOL HYPER condition had elevated metabolite concentrations after 10 minutes of stimulation in comparison to both HYPO and ISO (p<0.05), while EDL muscle did not show any significant difTerences between the HYPER or HYPO conditions. After 20 minutes of recovery, metabolic changes occurred in both SOL and EDL with the SOL HYPER condition showing greater relative changes in metabolite concentrations versus HYPO. The results of the current study have demonstrated that osmotic imbalance induces metabolic change within the skeletal muscle cell and muscle type may influence the mechanisms utilized for cell volume regulation.

The genetics of glucosamine in yeast : cytoplasmic determinants conferring resistance

Two cytoplasmic, glucosamine resistant mutants of Saccharomyces cerevisiae, GR6 and GR10, were examined to determine whether or not the lesions involved were located on mitochondrial DNA. Detailed investigation of crosses of GR6 and GR10 or their derivatives to strains bearing known mitochondrial markers demonstrated that: 1. the frequency of glucos~~ine resistance in diploids was independent of factors influencing mitochondrial marker output. 2. upon tetrad analysis a variety of tetrad ratios was observed for glucosamine resistance whereas mitochondrial markers segregated 4:0 or 0:4 (resistant:sensitive). 3. glucosamine resistance and mitochondrial markers segregated differentially with time. 4. glucosamine resistance persisted following treatment of a GRIO derivative with ethidium bromide at concentrations high enough to eliminate all mitochondrial DNA. 5. haploid spore clones displayed two degrees of glucosamine resistance, weak and strong, while growth due to mitochondrial mutations was generally thick and confluent. 6. a number of glucosamine resistant diploids and haploids, which also possessed a mithchondrial resistance mutation, were unable to grow on medium containing both glucosamine and the particular drug involved. 3 These observations 1~ 6 provided strong evidence that the cytoplasmic glucosamine resistant mutations present in GR6 and GRiO were not situated on mitochondrial DNA. Comparison of the glucosamine resistance mutations to some other known cytoplasmic determinants revealed that: 7. glucosamine resistance and the expression of the killer phenotype were separate phenomena. 8. unlike yeast carrying resistance conferring episomes GR6 and GR10 were not resistant to venturicidin or oligomycin and the GR factor exhibited genetic behaviour different from that of the episomal determinants. These results 7--+8 suggested that glucosamine resistance was not associated with the killer determinant nor with alleged yeast episomes. It is therefore proposed that a yeast plasmid(s), previously undescribed, is responsible for glucosamine resistance. The evidence to date is compatible with the hypothesis that GR6 and GR10 carry allelic mutations of the same plasmid which is tentatively designated (GGM).

Profitable opportunities around macroeconomic announcements in the U.S. Treasury market

This thesis studies the impact of macroeconomic announcements on the U.S. Treasury market and investigates profitable opportunities around macroeconomic announcements using data from the eSpeed electronic trading platform. We investigate how macroeconomic announcements affect the return predictability of trade imbalance for the 2-year, 5-year, IO-year U.S. Treasury notes and 30-year U.S. Treasury bonds. The goal of this thesis is to develop a methodology to identify informed trades and estimate the trade imbalance based on informed trades. We use the daily order book slope as a proxy for dispersion of beliefs among investors. Regression results in this thesis indicate that, on announcement days with a high dispersion of beliefs, daily trade imbalance estimated by informed trades significantly predicts returns on the following day. In addition, we develop a trade-imbalance based trading strategy conditional on dispersion of beliefs, informed trades, and announcement days. The trading strategy yields significantly positive net returns for the 2-year T-notes.

Sport-Specific Arbitration in Canada: A Qualitative Investigation of Four Athletes' Perceptions of the Fairness of the Process

This thesis explored Canadian high performance Athletes' perceptions of the fairness of the SDRCC sport-specific arbitral process. Leventhal’s (1980) model of procedural justice judgment was found to be an effective tool for exploring Athletes’ perceptions of the fairness of the process. Five of his six procedural justice antecedents: consistency, bias suppression, accuracy of information, representativeness, and ethicality influenced the Athletes’ perceptions of the fairness of the process. Emergent data also revealed that the Athletes’ perceptions of fairness were also influenced by three contextual factors and an additional antecedent of procedural justice. Efficiency of the process, inherent power imbalance between Athletes and NSOs, and the measurable effect of the process on personal and professional relationships differentiate sport-specific arbitration from most other processes of allocation. The data also indicated that the opportunity to voice one’s case was also an important determinant of the Athletes’ perceptions of the fairness of the process.

Bargaining Power Dynamics and the Negotiation of Commercial Rights and Obligations: A Case of Athlete Agreements

This qualitative case study explored how the structural power imbalance in high performance sport influenced the bargaining process and resulting commercial rights and obligations of a single Canadian national sport organization’s (NSO1) Athlete Agreement. Principles comprising the doctrine of unconscionability, specifically the identification of a power imbalance between contracting parties, and the exploration of how that power imbalance influenced the terms of the contract, provided a framework to analyze factors influencing the commercial contents of NSO1’s Athlete Agreement. The results of this analysis revealed that despite the overarching influence of the inherent structural power imbalance on all aspects of NSO1 and its membership, an athletes’ level of commercial appeal can reach such heights as to balance the bargaining positions of both parties and subsequently influence the commercial contents of the Athlete Agreement.

Genetic and Electrophysiological Correlates of Self-Regulation in Adolescence

Self-regulation is considered a powerful predictor of behavioral and mental health outcomes during adolescence and emerging adulthood. In this dissertation I address some electrophysiological and genetic correlates of this important skill set in a series of four studies. Across all studies event-related potentials (ERPs) were recorded as participants responded to tones presented in attended and unattended channels in an auditory selective attention task. In Study 1, examining these ERPs in relation to parental reports on the Behavior Rating Inventory of Executive Function (BRIEF) revealed that an early frontal positivity (EFP) elicited by to-be-ignored/unattended tones was larger in those with poorer self-regulation. As is traditionally found, N1 amplitudes were more negative for the to-be-attended rather than unattended tones. Additionally, N1 latencies to unattended tones correlated with parent-ratings on the BRIEF, where shorter latencies predicted better self-regulation. In Study 2 I tested a model of the associations between selfregulation scores and allelic variations in monoamine neurotransmitter genes, and their concurrent links to ERP markers of attentional control. Allelic variations in dopaminerelated genes predicted both my ERP markers and self-regulatory variables, and played a moderating role in the association between the two. In Study 3 I examined whether training in Integra Mindfulness Martial Arts, an intervention program which trains elements of self-regulation, would lead to improvement in ERP markers of attentional control and parent-report BRIEF scores in a group of adolescents with self-regulatory difficulties. I found that those in the treatment group amplified their processing of attended relative to unattended stimuli over time, and reduced their levels of problematic behaviour whereas those in the waitlist control group showed little to no change on both of these metrics. In Study 4 I examined potential associations between self-regulation and attentional control in a group of emerging adults. Both event-related spectral perturbations (ERSPs) and intertrial coherence (ITC) in the alpha and theta range predicted individual differences in self-regulation. Across the four studies I was able to conclude that real-world self-regulation is indeed associated with the neural markers of attentional control. Targeted interventions focusing on attentional control may improve self-regulation in those experiencing difficulties in this regard.

The Influence of Burnout Symptoms on the Relationship between Work-Life Balance and Self-Rated Health

The effects of stress at work are estimated to cost Canadian employers more than 20 billion dollars annually through absenteeism, sick leave and decreased productivity. Over the past two decades, Canadians have reported higher stress levels, increased work hours and more work performed outside of normal business hours. This work-life imbalance has far-reaching repercussions–affecting an employee’s performance as well as their health. Chronic exposure to these high levels of stress can also lead to burnout. The primary purpose of this study was to determine the magnitude in which burnout symptoms influence the relationship between work-life balance and self-rated health. The secondary purpose of this study was to determine if gender and age interactions exist in the relationship between burnout, work-life balance, and self-rated health. This cross-sectional study involved secondary analysis of 220 managers, workers and human service professionals who completed an Occupational Health Clinics for Ontario Workers’ Mental Injury Toolkit (MIT) survey for the launch of the MIT. The MIT survey is a modified form of the short version of the Copenhagen Psychosocial Questionnaire and includes expanded questioning around burnout, stress, sleep troubles, cognitive, and somatic symptoms. There were no significant differences in self-rated health based on a respondent’s gender or age, indicating that no interaction of gender and age would be required. Respondents with low self-rated health reported significantly higher burnout and work-life imbalance compared to those with high self-rated health. The regression analysis demonstrated that the magnitude in which burnout mediates the relationship between work-life balance and self-rated health was 96%. These findings support previous studies that associate high levels of work-life imbalance or burnout with poor self-rated health or health outcomes. In this study, the shared variance between work-life balance and burnout also supports recent efforts to redefine the context and causes of burnout to include non-work factors. Based on our findings, the potential exists for the development of workplace health promotion strategies that address maintaining a balance between work and home as they may improve employee health and reduce burnout.