Graduate Theses & Dissertations

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regional comparison of the structure and function of benthic macroinvertebrate communities within Precambrian Shield and St. Lawrence lowland lakes in south-central Ontario
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
Near-Hand Effects and Recruitment of Visual-Tactile Bimodal Cells
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
Models of partitioning, uptake, and toxicity of neutral organic chemicals in fish
Models of partitioning, uptake, and toxicity of neutral organic chemicals in fish Alena Kathryn Davidson Celsie A novel dynamic fugacity model is developed that simulates the uptake of chemicals in fish by respiration as applies in aquatic toxicity tests. A physiologically based toxicokinetic model was developed which calculates the time-course of chemical distribution in four tissue compartments in fish, including metabolic biotransformation in the liver. Toxic endpoints are defined by fugacity reaching a 50% mortality value. The model is tested against empirical data for the uptake of pentachloroethane in rainbow trout and from naphthalene and trichlorobenzene in fathead minnows. The model was able to predict bioconcentration and toxicity within a factor of 2 of empirical data. The sensitivity to partition coefficients of computed whole-body concentration was also investigated. In addition to this model development three methods for predicting partition coefficients were evaluated: lipid-fraction, COSMOtherm estimation, and using Abraham parameters. The lipid fraction method produced accurate tissue-water partitioning values consistently for all tissues tested and is recommended for estimating these values. Results also suggest that quantum chemical methods hold promise for predicting the aquatic toxicity of chemicals based only on molecular structure. Author Keywords: COSMOtherm, fish model, fugacity, Partition coefficient, tissue-water, toxicokinetics
Archaeological Investigation of the North Group at Pacbitun, Belize
This thesis reports on the 2010 excavations of the North Group and Eastern Court at the ancient Lowland Maya site of Pacbitun. It provides a construction history of the architecture and an analysis of associated artifacts, burials, and caches. The archaeological investigations demonstrate that the seven structures (Strs. 34-40) of this restricted access plazuela group were built in the Early Classic period, and renewed in the Late Classic period. Based on analyses of artifacts (ceramics and lithics), skeletal and faunal remains, and intra- and inter-site comparisons, the North Group functioned as a secondary elite domestic residential group. Reconstruction suggests that the inhabitants here were not commoners; instead, the occupants probably were related to the ruling elite of Pacbitun. Some of the evidence includes the central location and elevation of the North Group, the presence of red painted plaster surfacing, a burial with multiple ceramic musical instruments, and multiple dedicatory caches with exotic goods (e.g., marine shell, jadeite, "Charlie Chaplin" figures). Author Keywords: Ancient Maya, ceramic musical instruments, Charlie Chaplin figurines, Pacbitun, North Group, Eastern Court, Belize River Valley, Belize, restrictive access plazuela group, secondary elite
That They Might Sing the Song of the Lamb
This thesis examines Hildegard of Bingen (1098-1179)'s theology of music, using as a starting place her letter to the Prelates of Mainz, which responds to an interdict prohibiting Hildegard's monastery from singing the liturgy. Using the twelfth-century context of female monasticism, liturgy, music theory and ideas about body and soul, the thesis argues that Hildegard considered the sung liturgy essential to monastic formation. Music provided instruction not only by informing the intellect but also by moving the affections to embrace a spiritual good. The experience of beauty as an educational tool reflected the doctrine of the Incarnation. Liturgical music helped nuns because it reminded them their final goal was heaven, helped them overcome sin and facilitated participation in the angelic choirs. Ultimately losing the ability to sing the liturgy was not a minor inconvenience, but the loss of a significant spiritual and educational tool fundamental to achieving union with God. Author Keywords: Hildegard of Bingen, Letter to the Prelates of Mainz, liturgy, monasticism, music
Sponsoring Private Schools in an Informal Empire
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
"Energetics" of Mycenaean Defense Works
This thesis examines the mobilization of labour required for fortification construction during the Late Helladic (LH) period of the Aegean Bronze Age. It adopts an "energetics" approach to architecture, as a framework for systematically calculating the labour costs of construction, and using such costs to infer relative differences in political power among groups and communities through the implied differences in labour control. Accordingly, construction costs were generated for thirty-six LH fortifications, located across seven distinct regional zones of the Greek mainland and Aegean Sea. These values were then compared and evaluated against what is known of the political geographies for each region, to measure the extent to which the mobilization of labour was a function of regional power in Late Bronze Age Greece. These assessments revealed that a wide range of variation existed among the sampled regions in terms of the strength and nature of this connection, underscoring the diversity in labour relations that developed throughout the Aegean during the LH period. The labour costs were also used to suggest specific systems of recruitment that may have been in place for mobilizing workers, and to argue that fortification construction would not have been particularly burdensome or demanding for certain local populations. Author Keywords: Energetics, Fortifications, Late Bronze Age, Monumental Architecture
Holocene Resource Exploitation
This study uses the zooarchaeological record to examine the range of activities represented in Late Archaic period samples excavated from Jacob's Island -1B, in the Trent-Severn Waterway region in Ontario. Radiocarbon dates from sixteen features were used to establish a chronology of site use and occupation. The faunal remains analyzed in this study were recovered from seven dated mortuary features associated with human remains. The results of the faunal analysis suggest that Canis lupus familiaris was the primary species interred at Jacob's Island-1B. Small rodents, specifically Tamias striatus were also found in high abundance and are possibly the result of natural burrowing disturbances. Red ochre staining and low levels of burning were identified. Comparisons with other contemporaneous sites in the region indicate some variation in species composition. It is suggested that Canis lupus familiaris was associated with ritual and mortuary activities at Jacob's Island-1B. Author Keywords: Canis lupus familiaris, Late Archaic Period, Ontario, Ritualsim, Zooarchaeology
Local Immigration Partnerships
Introduced as part of the Canada-Ontario Immigration Agreement, Local Immigration Partnerships (LIPs) mark a fundamental shift in local settlement policy. To address the gap in knowledge about the implications of this policy change, this thesis research features a case study of Durham Region's LIP. Objectives were designed to examine the impact of Durham's LIP by interviewing 52 key-informants within six sectors involved in settlement and integration. Findings indicate an effective application of the LIP policy with participants pointing to the LIP's vital role in bringing Welcome Centres to Durham, increasing the attention and profile of immigration issues and improving governance relations amongst different sectors in settlement and integration. A product of local circumstances, the LIP has engaged in a quasi-advocacy role educating mainstream service providers and institutions on how to respond to a diversifying population. Results contribute to the relatively under-studied but growing knowledge of the LIP policy while demonstrating that the localization of immigration policy under the appropriate terms can be successful. Author Keywords: Governance, Integration, Local Immigration Partnerships, Ontario, Regionalization, Settlement
From Reading to Reality
This thesis explores post-millennial girl fiction, or young adult works published for girls since the turn of the millennium. Writing for girls has been traditionally placed beneath `more serious' literature, within a hierarchal model, while modern works enjoy an iconic status that is the product of cross-media popularity and a wide readership. Criticism has focused on post-millennial girl fiction being unwholesome, poorly written or anti-feminist, examination of the texts reveals personas which girls may use to explore, rebel against and critically examine societal expectations and fears about girlhood. To explore the publishing phenomenon surrounding current girls' fiction I use two sample series: Gossip Girl by Cecily Von Ziegesar and Twilight by Stephanie Meyer. Chapter One contrasts current girl's fiction with texts written about girlhood, followed with an analysis of the good-girl and bad-girl archetypes which are developed within the two groups of texts. I then consider the stylistic and structural elements presented within the fiction and the impact such elements may have on the girl public. In the conclusion, I consider the wider societal impacts of post-millennial girl fiction through social media, extended readership, cross-media influence and the responses of girl readers. Author Keywords: Feminist Criticism, girlhood, Gossip Girl series, public theory, Twilight series, young adult fiction
Absorbance and Fluorescence Characteristics of Dissolved Organic Matter in North Atlantic, Pacific and Arctic Oceans
This thesis was designed to quantify absorbance and fluorescence characteristics of dissolved organic matter (DOM) in North Atlantic, Pacific and Arctic Oceans. DOM was described in water masses of distinct sources and formation pathways as well as in regions where environmental forcings such as deep water upwelling, enhanced biological activity and receipt of freshwater discharge were prevalent. Influence of sea ice on DOM in Beaufort Sea mixed layer (0 to 30 m) seawater was investigated based on sea ice extent as well as freshwater fractions of meteoric (fmw) and sea ice melt water (fsim) calculated from oxygen isotope ratio (δ18O). The effect of DOM exposure to simulated solar radiation was also assessed to determine the resilience of fluorescent fractions of DOM to photodegradation. This research aims to further our ability to trace DOM in marine environments and better understand its transformation pathways and predict its fate as part of the oceanic carbon cycle in a changing climate. Author Keywords: Absorbance, Arctic Ocean, Dissolved organic matter, Fluorescence, Parallel Factor Analysis, Sea Ice
EMPIRE AND ITS PRACTITIONERS
In 1915 U.S. Marines invaded Haiti. Driven first by the epidemiological dangers in Haiti, health and medicine was made a central tenet in administering the occupation. Useful for protecting the American Marines from disease, the Service d'Hygiene (the occupation-era Public Health Service) also served a hegemonic purpose. By bringing American biomedicine to sick Haitians, the Service d'Hygiene built support for the occupation and helped foster long-term connections between Haiti and the United States. This hegemonic drive was made possible by the incorporation of non-state actors into the colonial project. To achieve this, the American authorities forged a development strategy for Haiti that was premised upon a relationship between the state and private institutions such as the Rockefeller Foundation. This strategy also encouraged Haiti to look to the United States for support, a goal successfully realized when Haitian politicians continued to do so even after the Marines left Haiti in 1934. Author Keywords: Haiti, Hegemony, Imperialism, Public Health, Rockefeller Foundation, Service d'Hygiene

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Graduate student theses produced at Trent University. You may also browse theses and dissertations by year, program, or author.

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1973 - 2033
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