Electronic Thesis or Dissertation

Benthic macroinvertebrtes (BMI) are functionally important in aquatic ecosystems; as such, knowledge of their community structure and function is critical for understanding these systems. BMI were sampled from ten lakes in each of two regions of south-central Ontario to investigate which chemical and physical variables could be shaping their community structure and function. Ten Precambrian Shield lakes in the Muskoka-Haliburton region, and ten St Lawrence lowland lakes in the Kawartha lakes region were sampled. These lakes are geologically and chemically distinct, creating natural chemical and physical gradients within and between both regions. Community function was assessed using stable isotope analysis to elucidate carbon transfer dynamics (δ13C) and food web interactions (δ15N). It was predicted that the BMI from Shield lakes would have a δ13C signature indicative of allochthonous carbon subsidies, whereas the lowland lake BMI signatures would reflect autochthonous production. Additionally, it was predicted that the food web length (measured in δ15N units) would be different in Shield and lowland lakes. Both of these predictions were supported; however, the data indicate that δ13C signatures are more likely influenced by catchment geology (represented by bicarbonate concentration) than the extent of allochthony. The best predictor of food web length was found to be region. To assess BMI community structure, taxonomic richness, %EPT (% Ephemeroptera, Plecoptera, Trichoptera; a water quality index), and distribution of functional feeding groups were examined. Based on chemistry it was expected that the Shield lakes would be more speciose, and of greater water quality (relatively lower nutrient levels). These predictions were rejected; since there were no significant regional differences in taxonomic richness or biologically inferred water quality (%EPT). However, sediment size was found to best explain the variability in both metrics, with greater richness and %EPT found at sites with medium and small substrates than those with large substrates. Significant regional differences were found in the distribution of functional feeding groups. Most notably, there were significantly greater proportions of scrapers and shredders in the lowland and Shield lakes, respectively. Based on the feeding mechanisms of these invertebrates it can be inferred that allochthonous subsidies are likely of greater importance to Shield lake BMI communities than those of the lowland lakes; supporting the carbon transfer prediction. These findings provide insight about the structure and function of BMI communities from two dominant lake types in Ontario, and could be useful when determining how future chemical and physical changes will impact these communities.

Author Keywords: benthic macroinvertebrates, community function, community structure, Precambrian Shield, stable isotopes, St. Lawrence lowlands

Eastern wolves (Canis lycaon) have hybridized extensively with coyotes (C. latrans) and gray wolves (C. lupus) and are listed as a `species of special concern' in Canada. Previous studies have not linked genetic analysis with field data to investigate the mechanisms underlying Canis hybridization. Accordingly, I studied genetics, morphology, mortality, and behavior of wolves, coyotes, and hybrids in and adjacent to Algonquin Provincial Park (APP), Ontario. I documented 3 genetically distinct Canis types within the APP region that also differed morphologically, corresponding to putative gray wolves, eastern wolves, and coyotes. I also documented a substantial number of hybrids (36%) that exhibited intermediate morphology relative to parental types. I found that individuals with greater wolf ancestry occupied areas of higher moose density and fewer roads. Next, I studied intrinsic and extrinsic factors influencing survival and cause-specific mortality of canids in the hybrid zone. I found that survival was poor and harvest mortality was high for eastern wolves in areas adjacent to APP compared with other sympatric Canis types outside of APP and eastern wolves within APP. Contrary to previous studies of wolves and coyotes elsewhere, I hypothesized that all Canis types exhibit a high degree of spatial segregation in the Ontario hybrid zone. My hypothesis was supported as home range overlap and shared space use between neighboring Canis packs of all ancestry classes were low. Territoriality among Canis may increase the likelihood of eastern wolves joining coyote and hybrid packs and exacerbate hybridization. Canids outside APP modified their use of roads between night and day strongly at high road densities (selecting roads more at night), whereas they responded weakly at lower road densities (generally no selection). Individuals that survived exhibited a highly significant relationship between the difference in their night and day selection of roads and availability of roads, whereas those that died showed a weaker, non-significant response. My results suggest that canids in the unprotected landscape outside APP must balance trade-offs between exploiting benefits associated with secondary roads while mitigating risk of human-caused mortality. Overall, my results suggest that the distinct eastern wolf population of APP is unlikely to expand numerically and/or geographically under current environmental conditions and management regulations. If expansion of the APP eastern wolf population (numerically and in terms of its geographic distribution) is a conservation priority for Canada and Ontario, additional harvest protection in areas outside of APP may be required. If additional harvest protection is enacted, a detailed study within the new areas of protection would be important to document specific effects on eastern wolf population growth.

Author Keywords: Canis, coyotes, eastern wolves, hybridization, resource selection, survival

Silver nanoparticles (AgNP) released into aquatic environments could threaten natural bacterial communities and ecosystem services they provide. We examined natural lake bacterioplankton communities' responses to different exposures (pulse vs chronic) and types (citrate and PVP) of AgNPs at realistic environmental conditions using a mesocosm study at the Experimental Lakes Area. An in situ bioassay examined interactions between AgNPs and phosphorus loading. Bacterial communities exposed to high AgNP concentrations regardless of exposure or capping agent type accumulated silver. We observed increases in community production during additions of polyvinylpyrrolidone (PVP) -capped AgNPs and that site and nutrient-specific conditions are important to AgNPs toxicology in aquatic systems. Toxicological effects of AgNP are attenuated in natural conditions and differ from results from laboratory studies of AgNP toxicity. Our results demonstrate more studies are needed to fully assess the risk posed by these novel chemicals to the environment. This work could be useful in forming risk assessment policies which are largely based on lab studies and typically demonstrate strong toxic effects.

Author Keywords: bacterial production, bacterioplankton communities, ecological stoichiometry, Experimental Lakes Area, mesocosms, silver nanoparticles

Dreams that occur in bereavement have been mainly overlooked in the psychological literature. This study focuses on the most memorable dreams of the bereaved that contain imagery of the deceased. There were 52 participants who completed the study via email. The main goal of the study was to investigate the occurrence of common themes in the dreams that have the deceased as a character. It was hypothesized that the most memorable dreams are memorable because they positively influenced the dreamers waking life grief process, which was partially supported. Furthermore, it was expected that that the most memorable dreams will have a greater frequency of positive elements and a lower frequency of negative elements than the normative data on dreams, which was partially supported. These findings support past research on dreaming of the deceased and expand the impact that these types of dreams can have on the grief process.

Author Keywords: bereavement, deceased imagery, dream content, dreams, grief

It has long been hypothesized the location of the ancient Maya center of Minanha was a strategic one based on its ability to control the flow of communication and key resources between major geopolitical zones. Situated in the Vaca Plateau, at the nexus of the Belize River Valley, the Petén District of Guatemala, and the Maya Mountains, Minanha became a Late Classic polity capital that was tapped into a regional economy as well as long-distance trade networks. In this thesis I present a GIS-based spatial analysis that includes viewshed and cost surface analysis (CSA) to model visibility and movement within the north Vaca Plateau and neighboring regions to address specific questions concerning Minanha's strategic value. The results indicate that Minanha occupied a visually prominent location in proximity to major corridors of movement that suggest it was strategically, and in fact ideally located, as a polity capital with the ability to monitor the movement of people and resources.

Author Keywords: Belize, GIS, Least Cost Path, Maya, Minanha, Viewshed

Near-hand benefits are seen when individuals are able to process targets more quickly, accurately, and with greater precision when a hand is placed near, rather than far from a target. One possibility is that near-hand stimuli recruit visual-tactile bimodal cells. Research reports that placing a hand near a target delayed immediate saccade onset and speeded delayed saccade onset. Study 1 examined saccade onset to targets appearing near a real hand, a realistic fake hand, or a non-hand visual cue. Immediate saccades were facilitated and delayed saccades were slowed with a real hand in the display, in comparison to a fake hand and no-hand. To establish the link between near-hand effects and bimodal cells, Study 2 used repetitive transcranial magnetic stimulation (rTMS) to depress cortical activity in PMd. RTMS did not induce a reversal of interference induced by near-hand, congruent targets. However, a reversal of the hand effect was found in the stimulation group; a real hand in the display may delay immediate saccades and improve delayed saccades post-stimulation. This finding may double dissociate the effect of the real hand from the fake hand and may be inconsistent with the hypothesis that the hand is attracting attention.

Author Keywords: multisensory integration, near-hand effects, PMd, premotor cortex, rTMS, visual-tactile bimodal neurons

This thesis analyzes the history of the Inter-American Schools Service (IASS), which ran under the auspices of the American Council on Education beginning in 1943. The program was defined as a private initiative aimed at spreading U.S. democratic values throughout the hemisphere for the mutual benefit of both the United States and Latin America. Yet the program was ultimately one facet of the United States' informal imperialism and a tool for the consolidation of U.S. hegemony, which came at the expense of Latin Americans' pursuit of the very values the IASS was said to facilitate. This theme is explored through a general discussion of cultural policy in the twentieth-century United States as well as the specific history of the IASS program and its relation to U.S. policies of intervention in Guatemala and Bolivia.

Author Keywords: American Schools, Cultural Imperialism, Guatemala, Hegemony, Informal Imperialism, Inter-American Schools Service

This dissertation is an inquiry into the politics of the frame in Canadian refugee policy. It is focused on "framing," thereby taking up the stance of critical policy studies while pressing the contribution of Donald Schön and Martin Rein in a critical and politically inflected direction. The dissertation unfolds as a political history of Canadian refugee policy that provides a "contextual mapping," relevant to both inquiry and action in regard to the framing of refugees. The main argument is that twentieth- and twenty-first- century refugee policy in Canada is a story of three shifting meta-frames: beginning with humanitarianism (in the inter-War years and the post-World War II period); shifting to neo-humanitarianism (beginning in the late 1970s, in connection with the rise of neoliberalism); then shifting again (beginning in the 1990s) to securitization. The concept of a meta-frame here is analogous to that of a "metacultural frame" in Schön and Rein, but accents political rather than cultural dimensions. This concept is developed in a manner suitable to a political history by illustrating how meta-frames both become stable and change. With humanitarianism, the refugee was typically portrayed in ambivalent terms - both deserving of and entitled to protection, while also posing a burden for the national interest. In the context of neo-humanitarianism, this ambivalence began to wane, and the refugee was more typically portrayed as a potential criminal. With securitization, especially as it has become entrenched and intensified, the refugee has been more typically portrayed as a potential terrorist. The analysis includes a focus on the particular importance of ambivalence and contingency in the politics of the frame. Securitization has become so deeply entrenched since September 11, 2001 that it appears virtually fixed in place. However, it may still become possible in moments of contingency for refugee advocates to destabilize the securitization meta-frame and help shift the framing of refugees into a more hospitable register.

Author Keywords: ambivalence, contingency, humanitarianism, neo-humanitarianism, refugees, securitization

This thesis examines the social impact of horses on French elites between 1150 and 1300. Using courtly literature, a veterinary treatise, manuscript illuminations, archeological studies, material artefacts, and account books, it explores the place of horses in elite society—practical and symbolic—and assesses the social costs of elite use and ownership of horses. While horses served practical functions for elites, their use and investment in horses clearly went far beyond practicality, since elites used horses recreationally and sought prestigious horses and highly decorated equipment. Their owners used horses in displays of power, status, and wealth, as well as in displays of conspicuous consumption and the performance of gender roles. The social display associated with horses was integrally tied to the ideology and performance of chivalry. This study examines the broader use of horses by elites to understand their place in the elite culture of the High Middle Ages.

Author Keywords: Horses, Knighthood, Medieval France, Military History, Nobility, Social History

In this thesis, aerosolization was studied as a possible means of water remediation for several environmentally relevant pharmaceutical pollutants, known for their persistence in wastewater effluent and potable water sources. Seven different pharmaceutical compounds and a well-known plasticizer were all shown to decrease considerably in concentration in aerosol that was produced and subsequently collected within a short time span. Strong evidence is presented that an enhanced rate of partitioning into the gas phase at the air-water interface of water droplets exists for every compound tested relative to that occurring in bulk solution. UV photolysis in aerosols was also explored and shown for sulfamethoxazole to be at least an order of magnitude faster in aerosols then in bulk solution. The implications towards both the environmental fate, and removal of these compounds from water sources is discussed.

Author Keywords: Aerosols, Air-water partitioning, Pharmaceuticals, Photolysis, Sulfamethoxazole