No description available.

Daily net ecosystem CO$ sb2$ exchange (NEE) was monitored at several peatland communities in a mid-boreal headwater bog at the Experimental Lakes Area (Kenora, ON., Canada) throughout the 1995-96 growing seasons. Transparent and opaque chamber systems were used to measure NEE and dark respiration at replicate plots in which the vascular vegetation was either clipped or unclipped. CO$ sb2$ fixation and emission fluxes were estimated from NEE measurements and were compared within and among the peatland communities. Communities that supported shrubby, xerophytic vegetation fixed CO$ sb2$ at rates that ranged from, on average, 0.194 to 0.365 mg CO$ sb2$ m$ sp{-2}$ s$ sp{-1}$. These rates did not vary significantly on a daily to weekly timescale, and were comparable in magnitude to the wetter, sedge-dominated communities. CO$ sb2$ emissions varied within and among communities across the sampling season. Rates were, on average, from 0.0568 to 0.109 mg CO$ sb2$ m$ sp{-2}$ s$ sp{-1}$, and the variation was associated with differences in ground temperature and water table. Comparisons of CO$ sb2$ emissions from clipped and unclipped plots allowed an estimation of the contribution of vascular respiration to total CO$ sb2$ emissions. Contributions ranged from 25 to over 80%, depending on the community and season that the measurements were taken. Strong associations between vascular respiration and ground temperature were observed. Daily NEE had little variability between communities and throughout the sampling season. This was attributed to parallel variations for the CO$ sb2$ fixation and emission fluxes. Researchers should quantify the actual fluxes for vascular root respiration, as it possibly controlled a large part of the NEE variability within and between sites.

Many elderly patients remain in acute care hospitals while they await transfer to Long Term Care (LTC) facilities. Complex problems, common for this special group of patients, place them at risk for delayed discharge. Discharge planning, for these patients, has become an increasingly critical activity for social workers. / This study examined factors that predict the risks for inappropriate hospitalization for 244 patients waiting for LTC in 1999, and it explored the LTC application process to identify barriers to delayed discharges. / It was found that 63% of the hospitalization of these patients was inappropriate. System related factors, such as the timing of the LTC application, were identified as predictors. Timeline investigations revealed areas for improvement in the discharge process and were discussed with a view to social work implementation, for example, the introduction of a high-risk screening protocol.

Filter-feeding macrozooplankton were collected from 24 lakes in south-central Ontario to examine relationships between environmental factors and methyl mercury accumulation. Zooplankton methyl mercury levels ranged from 19 to 448 ng$ rm cdot g sp{-1}$ dry weight in the study lakes and were highest in zooplankton from acidic brownwater lakes. Water color and lake water pH were the best predictors of methyl mercury levels in zooplankton explaining 73% of the variation. Methyl mercury concentrations were positively correlated with water color and inversely correlated with lake water pH. Water color explained a greater portion of the overall variance in methyl mercury levels, indicating that the supply of mercury from the drainage basin plays a key role in determining methyl mercury concentrations in the lacustrine biota. Zooplankton methyl mercury levels were well correlated with mercury concentrations in smallmouth bass (Micropterus dolomieui) and largemouth bass (Micropterus salmoides) from 11 of the study lakes showing zooplankton to be good indicators of the relative bioavailability of mercury at the base of the food chain.

In recent years there has been a notable increase in the number of suicides amongst South Asian youth in the Region of Peel in Ontario. Using a six-page questionnaire, an exploratory descriptive study was conducted with 104 participants. The purpose of the study was to inquire into the number of South Asian youth that had ever considered committing suicide; determine whether there were any predicting factors; and gain insight as to "why." It was found that close to 30% of the sample had considered suicide and that gender, place of birth and a self-rating scale of depression were significant variables. Of those who had admitted to having considered suicide, 'family pressures' was cited as the number one reason.

Takeovers play an important role in the economy as they serve to reallocate economic resources to more efficient uses and replace inefficient management. Unregulated takeover bids pose a threat to the interests of the target company shareholders. The legislature pays special attention to takeover bids to make sure that the bona fide interests of the target company shareholders are duly protected. This is the primary purpose of the takeover bid regulation in Ontario. The regulation is also aimed at ensuring the horizontal equity among target shareholders and the efficient functioning of the capital market. This thesis analyzes the present regulation of takeover bids in Ontario and argues that while the whole system of takeover bid regulation is consistent with the proclaimed purposes, there are two issues that fall out of the coherent structure. The restriction on free transferability of shares and the adoption by boards of directors of shareholder rights plans do not enhance the protection of target company shareholders and do not correspond to the proclaimed purposes.

The lake breeze is shown to develop on 30% of all summer days in the Toronto region, similar to other findings in the Great Lakes area. Simulations with the Colorado State University (CSU) model show that under northwest to north gradient flow the lake breeze is characterized by a broad band of westerlies over the lake, while southwesterly gradient flow produces a broad band of easterlies. A nocturnal mesoscale cyclonic eddy is predicted over western Lake Ontario under west and northwest gradient flow conditions. / A statistical model intercomparison of the CSU and Ontario Ministry of Environment models over a 19600 km$ sp2$ domain centred on Pickering, ON revealed the CSU model generally more accurately predicts the temporal and spatial lake breeze characteristics. This is attributed to improved model parameterizations and larger domain size enabling the model to resolve the full-lake scale circulations which develop.

Thesis (Ph.D.)--McMaster University, 2006. / Supervisor: K. Cruikshank. Includes bibliographical references (leaves 344-370).

Thesis (M.F.A.)--University of Wyoming, 2009. / Title from PDF title page (viewed on Apr. 16, 2010).

A review of the current understanding of forest tent caterpillar (Malacosoma disstria Hbn.) population dynamics in Ontario suggests that two climatic factors, the temperature at the time of larval feeding and the minimum temperature through the winter, play important roles in determining outbreaks. Comparing the pattern of defoliation to similarly scaled temperature records over 41 years in Ontario shows no relationship between the year to year dynamics of outbreaks and either the temperature through the larval feeding period or the minimum overwintering temperature. A long-term analysis suggests that outbreaks are less severe in those regions with low overwintering temperatures and a patchy distribution of host. This latter finding, combined with an analysis of the synchrony and spread of defoliation, suggests that adult dispersal may play an important role in shaping the dynamics of outbreaks. / Science, Faculty of / Zoology, Department of / Graduate