Constraint-based models of metabolism seldom incorporate capacity constraints on intracellular fluxes due to the lack of experimental data. This can sometimes lead to inaccurate growth phenotype predictions. Meanwhile, other forms of data such as fitness profiling data from growth competition experiments have been demonstrated to contain valuable information for elucidating key aspects of the underlying metabolic network. Hence, the optimal capacity constraint identification (OCCI) algorithm is developed to reconcile constraint-based models of metabolism with fitness profiling data by identifying a set of flux capacity constraints that optimally fits a wide array of strains. OCCI is able to identify capacity constraints with considerable accuracy by matching 1,155 in silico-generated growth rates using a simplified model of Escherichia coli central carbon metabolism. Capacity constraints identified using experimental fitness profiles with OCCI generated novel hypotheses, while integrating thermodynamics-based metabolic flux analysis allowed prediction of metabolite concentrations.

Fluxes of sensible and latent heat were measured over a grassland during 1998 and 1999 using the eddy covariance technique. The study objectives were to document seasonal and interannual variation evapotranspiration. Bowen ratios were lower in 1998 (0.5-3.0) than in 1999 (2.5-8.5) due to lower evapotranspiration rates (E). Maximum E also occurred later in 1998 than in 1999; Day 188 (10.4 mmol m-2s-1) versus Day 152 (5.6 mmol m-2s-1). Daily evapotranspiration rates were positively correlated with net radiation, canopy conductance, plant nitrogen content, leaf area index and soil moisture. Based on calculations of the decoupling coefficient (O). evapotranspiration was more constrained by canopy conductance in 1999 (O<0.2) than in 1998 (O>0.3). Evapotranspiration and energy partitioning in this grassland were sensitive to seasonal changes in soil moisture and interannaual variation in spring precipitation. Annual evapotranspiration was 300 mm. / x, 70 leaves : ill. ; 28 cm.

Carbon Dioxide (CO2) is a major fermentation product generated during the production of beer, the subsequent release of this gas within the fermentor results in agitation that is necessary for sustained industrial fermentation. CO2 is sometimes monitored allowing brewers to stoichiometrically relate CO2 released to other products. In this manner the rate of gas release from the fermentor may be used to assess, control and predict other aspects of fermentation. The dynamics of CO2 generation, transport and release are explored throughout this thesis over several studies. The tools used to examine CO2 production were scrutinized including a miniature assay using various modeling techniques. A miniature scale fermentation assay included in the methods of the American Society of Brewing Chemists was compared to industrial scale fermentations. It was found that discrepancies were possibly due (at least in part) to fermentor geometry. Following this study, a literature review of CO2 solubility in aqueous sugar, and ethanol solutions was conducted. This study exposed previously undescribed inaccuracies in literature, i.e., it was found that several gas solubility tables were empirical derived and are therefore unlikely to accurately reflect all styles of beer. The next study scrutinized the consumption of sugars during barley fermentation and found that these fermentations often exhibit asymmetric sigmoidal attenuation. A five parameter logistic model was introduced to model this sugar consumption more accurately than previously described techniques. Using methods refined during the aforementioned studies, a fermentation was conducted where a mass balance was used to track all major fermentation parameters (the consumption of individual sugars, and the production of ethanol, carbon dioxide, yeast biomass and glycerol). This allowed an assessment of Balling’s theorem as compared to modern theory. It was shown that while accurate in predicting original extract, Balling’s theorem incorrectly quantified other fermentation parameters. This has large ramifications for both industry and research as the estimation of fermentation parameters (such as ethanol and fermentation time) is now better understood. From these studies, the production of beer becomes less of a “black box” operation, and CO2 saturation, transport and release can be better explained. Of the many fermentation aspects monitored during these studies, most were predicted by theory, however, there were notable exceptions. For instance, it was found that both the inhibition of maltose consumption and yeast sugar consumption dynamics (which remained relatively constant throughout the fermentation at ~ 50 pg·h-1 for cells with an average mass of ~ 40 pg). were found to deviate from previously described reports. These, and other findings improve our understanding of brewing fermentations allowing for additional applications of theory and recommendations in industrial operations.

Rationale: Consumers of the mental health system with serious mental illness have been deprived of meaningful occupations since de-institutionalization began in the late 20th century.Community mental health policy has failed to focus on the meaningful occupational lives of this group of service users. Given the disparity in activity and meaningful time use for people with serious mental illness when compared to the general population, it is clear that a treatment that draws attention to occupational balance and engagement is needed. As balanced time use has been shown to increase community adjustment and life satisfaction, it is an important area of focus. Objectives: The purpose of this study was to pilot test the efficacy of a new occupational time use intervention, provisionally titled “Action over Inertia,” designed to increase occupational balance and engagement in the lives of people with serious mental illness living in the community. Methods: A prospective, multi-centre randomized controlled trial of the intervention, involving 5 Assertive Community Treatment (ACT) teams in southeastern Ontario,ran in Fall 2007/Winter 2008. 18 ACT clients took part in the 12 week intervention, which was delivered by the ACT team occupational therapists. Results: Time use, used as a measure of occupational balance, shifted away from sleep to increased general activity in the treatment group(p=0.05). Treatment and control groups did not differ on occupational engagement measures after the completion of the trial. Feedback on the clinical utility of the intervention was very positive from both therapists and treatment participants. Conclusions: This pilot test revealed initially positive data on the efficacy and clinical utility of the intervention.Further study of the “Action over Inertia” intervention is needed on a larger scale, potentially with a longer treatment timeline to further investigate its usefulness. / Thesis (Master, Rehabilitation Science) -- Queen's University, 2008-09-22 14:36:47.279

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