eng

The literature to date that investigates the development of social perspective taking in children primarily focuses on preschool aged children. These studies provide evidence that implicates language as being crucial for social perspective taking in young children but less is known about the importance of language to social perspective taking during middle childhood and early adolescence. The current study uses Selman's theory of socio-cognitive development to investigate the maturation of social perspective taking and the importance of language to social problem solving in 8 year olds (n = 111) and 12 year olds (n = 112). Analysis of variance and scalogram analysis shows a developmental progression of social perspective taking across the social problem solving process. Children may be able to demonstrate reciprocal perspective taking when generating strategies before they are able to demonstrate reciprocal perspective taking for other steps of social problem solving. Flexibility in interpersonal orientation is shown to be a predictor of social problem solving ability. Correlations and multiple regression analysis demonstrate that language is important to overall social problem solving but that the role of semantic and syntactic language may differ at age 8 compared to age 12.

Author Keywords: interpersonal orientation, language, Selman, social cognition, social perspective taking, social problem solving

Comprehending the dynamics of infectious diseases is very important in formulating public health policies to tackling their prevalence. Mathematical epidemiology (ME) has played a very vital role in achieving the above. Nevertheless, classical mathematical epidemiological models do not explicitly model the behavioural responses of individuals in the presence of prevalence of these diseases. Economic epidemiology (EE) as a field has stepped in to fill this gap by integrating economic and mathematical concepts within one framework. This thesis investigated two issues in this area. The methods employed are the standard linear analysis of stability of dynamical systems and numerical simulation. Below are the investigations and the findings of this thesis:

Firstly, an investigation into the stability properties of the equilibria of EE

models is carried out. We investigated the stability properties of modified EE systems studied by Aadland et al. [6] by introducing a parametric quadratic utility function into the model, thus making it possible to model the maximum number of contacts made by rational individuals to be determined by a parameter. This parameter in particular influences the level of utility of rational individuals. We have shown that if rational individuals have a range of possible contacts to choose from, with the maximum of the number of contacts allowable for these individuals being dependent on a parameter, the variation in this parameter tends to affect the stability properties of the system. We also showed that under the assumption of permanent recovery for

disease coupled with individuals observing or not observing their immunity, death

and birth rates can affect the stability of the system. These parameters also have

effect on the dynamics of the EE SIS system.

Secondly, an EE model of syphilis infectivity among &ldquo men who have sex with men &rdquo (MSM) in detention centres is developed in an attempt at looking at the effect of behavioural responses on the disease dynamics among MSM. This was done by explicitly incorporating the interplay of the biology of the disease and the behaviour of the inmates. We investigated the stability properties of the system under rational expectations where we showed that: (1) Behavioural responses to the prevalence of

the disease affect the stability of the system. Therefore, public health policies have the tendency of putting the system on indeterminate paths if rational MSM have complete knowledge of the laws governing the motion of the disease states as well as a complete understanding on how others behave in the system when faced with risk-benefit trade-offs. (2) The prevalence of the disease in the long run is influenced by incentives that drive the utility of the MSM inmates. (3) The interplay between the dynamics of the biology of the disease and the behavioural responses of rational MSM tends to put the system at equilibrium quickly as compared to its counterpart (that is when the system is solely dependent on the biology of the disease) when subjected to small perturbation.

Author Keywords: economic and mathematical epidemiology models, explosive path, indeterminate-path stability, numerical solution, health gap, saddle-path stability, syphilis,

Natural populations of flowering plants rarely have perfectly uniform distributions, so trends in pollen dispersal should affect the size of the pollination neighbourhood and influence mating opportunities. Here I used spatial analysis to determine the size of the pollination neighbourhood in a stand of the herbaceous, wind-pollinated plant (Typha latifolia; broad-leaved cattail) by evaluating patterns of pollen production and seed set by individual cattail shoots. I found a positive correlation between pollen production and seed set among near-neighbour shoots (i.e., within 4 m2 patches of the stand; Pearson's r = 0.235, p < 0.05, df = 77) that was not driven by a correlation between these variables within inflorescences (Pearson's r = 0.052, p > 0.45, df = 203). I also detected significant spatial autocorrelations in seed set over short distances (up to ~ 5 m) and a significant cross-correlation between pollen production and seed set over distances of < 1 m indicating that the majority of pollination events involve short distances. Patterns of pollen availability were simulated to explore the shape of the pollen dispersal curve. Simulated pollen availability fit actual patterns of seed set only under assumptions of highly restricted pollen dispersal. Together, these findings indicate that even though Typha latifolia produces copious amounts of pollen, the vast majority of pollen dispersal was highly localized to distances of ~ 1 m. Moreover, although Typha latifolia is self-compatible and has been described as largely selfing, my results are more consistent with the importance of pollen transfer between nearby inflorescences. Therefore, realized selfing rates of Typha latifolia should largely depend on the clonal structure of populations.

Author Keywords: clonal structure, correlogram, dispersal curves, pollination, spatial analysis, Typha latifolia

This thesis examines how food, culture and identity are linked to the idea of "home." Through a reading of oral narratives produced on the YouTube channel "ShowMetheCurry," I investigate how presenters Anuja and Hetal "write back" from a diasporic space in Texas, to the YouTube global public, and how food and cuisine, even in the age of globalization can be problematic in terms of representation of identities, work and space. I explore how the YouTube videos operate as a heterotopia, as what is presented to the audience in this medium is an embedding of spaces. The space that is projected through "ShowMetheCurry," that of Anuja and Hetal's own home kitchen, is then projected and viewed within the audiences' own spaces, in various locations around the world. What connects these spaces is an interest in cooking, and a longing to satiate culinary nostalgia.

Author Keywords: Affect, Culinary nostalgia, Discourse analysis, Food culture, South Asian Diaspora, YouTube

Least cost path analysis is considered by many scholars as being a good proxy for studying movement and interactions between sites in the landscape. Although it is widely used, there are many limitations and challenges yet to be overcome concerning the reliability of the results. The examples used from the Göksu Valley during the late Roman Imperial rule emphasize the need to clearly understand how the tool works in generating least cost paths and how these can be interpreted and related to human movement. The resolution and accuracy of the elevation data used also play an important role in least cost path analysis and these depend on the topographical area being studied. New venues are constantly being sought and the success of any analysis depends on how the results are compared and tested in concert with data obtained from various sources and through more visually advanced mapping software.

Author Keywords: GIS, Göksu Valley, Turkey, Late Roman period, Least cost path, Roads, Routes, Communication, Spatial analysis

Peatlands are prevalent in the Sudbury, Ontario region. Compared with the well documented devastation to the terrestrial and aquatic ecosystems in this region, relatively little work has been conducted on the peatlands. The objective of this research was to assess factors controlling peat and plant chemistry, and vegetation composition in 18 peatlands in Sudbury after over 30 years of emission reductions. Peatland chemistry and the degree of humification varies considerably, but sites closer to the main smelter had more humified peat and the surface horizons were enriched in copper (Cu) and nickel (Ni). Copper and Ni concentrations in peat were significantly correlated with Cu and Ni in the plant tissue of leatherleaf, although the increased foliar metal content did not obviously impact secondary chemistry stress indicators. The pH and mineral content of peat were the strongest determining factors for species richness, diversity and community composition. The bryophyte communities appear to be acid and metal tolerant, although Sphagnum mosses are showing limited recovery.

Author Keywords: anthropogenic emissions, bryophytes, community comspoition, heavy metals, peatlands, wetland vegetation

The efficacy of the diffusive gradients in thin films (DGT) passive samplers to provide accurate measurements of free metal ions and those complexed with dissolved organic matter (DOM) was investigated. DOM controls the diffusive properties of DOM-complexed metal species in natural systems. Knowing the diffusion coeiffiecent (D) for DOM of different molecular weights (MW) and the major environmental variables influencing D is critical in developing the use of DGT passive samplers and understanding labile species. D and MW were determined for natural and standard DOM. No noticeable changes in DOM MW were observed during the diffusion process, suggesting that DOM remains intact following diffusion across the diffusive gel. Data analysis revealed that MW had the greatest influence on D, with a negative relationship between D and MW, except in tidal areas where ionic strength influence on D was significant. This study provides further characterization of the variables influencing D using the DGT technique.

Author Keywords: Diffusion coefficient, Diffusive gradients in thin films, Dissolved organic matter, Flow field-flow fractionation, Principal Component Analysis, UV-Vis Spectroscopy

Catchment soil acidification has been suggested as a possible mechanism for reducing phosphorus (P) loading to surface waters in North America and northern Europe, but much of the research that has been conducted regarding P immobilization in pH manipulated soils has been performed at high P concentrations (> 130 μM). This study investigated how soil acidity was related to P fractionation and P sorption at environmentally relevant P concentrations to evaluate the potential influence of long term changes in soil pH on P release to surface waters. Total phosphorus (TP) concentrations declined between 1980 and 2000 in many lakes and streams in central Ontario; over the same time period forest soils in this region became more acidic. Soils were collected from 18 soil pits at three forested catchments with similar bedrock geology but varying TP export loads. The soil pH at the 18 study soil pits spanned the historic soil pH range, allowing for `space for time' comparison of soil P factions. Soils were analysed by horizon for P fractions via Hedley P fractionation. Batch P sorption experiments were performed on selected B-horizon soils at varied solution pH. Soil P fractions varied by horizon but were comparable among the three catchments, with only apatite (PHCl) differing significantly across catchments. Contrary to expectation, both soluble and labile P showed negative relationships with pH in some horizons. Mineral soils were able to sorb almost all (> 90 %) of the P in solution at environmentally relevant P concentrations (4.5 - 45.2 μM). Phosphorus sorption at environmentally relevant P concentrations was unrelated to solution pH but at high P concentration there was a positive relationship between P sorption and solution pH, suggesting a P concentration dependant P sorption mechanism. Phosphorus budgets indicate that P is accumulating within catchments, suggesting that P is being immobilized in the terrestrial environment. An alternative hypothesis, which attempts to explain both the decline in stream TP export and terrestrial P accumulation, is discussed. The results from this study suggest that acidification induced P sorption in upland soils are not a contributing factor to decreases in stream TP concentration in the study catchments.

Author Keywords: central Ontario, Hedley fractionation, phosphorus, podzols, soil acidification, sorption

Medication used to treat human illness is one of the greatest developments in human history. In Canada, prescription drugs have been developed and made available to treat a wide variety of illnesses, from infections to heart disease and so on. Records of prescription drug fulfillment at coarse Canadian geographic scales were obtained from Health Canada in order to track the use of these drugs by the Canadian population.

The obtained prescription drug fulfillment records were in a variety of inconsistent formats, including a large selection of years for which only paper tabular records were available (hard copies). In this work, we organize, digitize, proof and synthesize the full available data set of prescription drug records, from paper to final database. Extensive quality control was performed on the data before use. This data was then analyzed for temporal and spatial changes in prescription drug use across Canada from 1990-2013.

In addition, one of major research areas in environmental epidemiological studies is the study of population health risk associated with exposure to ambient air pollution. Prescription drugs can moderate public health risk, by reducing the drug user's physiological symptoms and preventing acute health effects (e.g., strokes, heart attacks, etc.). The cleaned prescription drug data was considered in the context of a common model to examine its influence on the association between air pollution exposure and various health outcomes. Since, prescription drug data were available only at the provincial level, a Bayesian hierarchical model was employed to include the prescription drugs as a covariate at regional level, which were then combined to estimate the association at national level. Although further investigations are required, the study results suggest that the prescription drugs influenced the air pollution related public health risk.

Author Keywords: Data, Error checking, Population health, Prescriptions

Two dominant narratives emerging throughout the war were the national narrative––that is, the narrative of the war as articulated by the British nation via texts such as political speeches, recruitment posters, and popular music–– and the poetic narrative––that is, the narrative of the war emerging from poets, specifically battlefront poets for the sake of this thesis. One hundred years since World War One, these two narratives are often conceptualized as mutually exclusive, even antithetical to one another. This thesis brings these diverse narratives into conversation with one another by investigating how they both draw on the same rhetorics and yet use these rhetorics to differing ends. Interestingly, the rhetorics employed by both narratives throughout the war endure in contemporary remembrance practices in Britain today. By investigating how each narrative draws on and employs the same rhetorics, this thesis both contextualizes and complexifies contemporary interpretations of contemporary remembrance practices.

Author Keywords: Battlefront Poetry , Britain, Narrative, Remembrance, Rhetoric, World War One