Carleton University Institutional Repository
Not a member yet
20816 research outputs found
Sort by
Effects of Pesticide Exposure and Experimental Temperatures on Amphibian Immunity and Stress
Get PDFAmphibians are experiencing global declines, partly due to pesticides, climate change and emerging diseases. These factors do not always act independently but can interact to have exacerbated effects. Independently, pesticides and warming can cause stress and reduce immunity in amphibians, increasing disease susceptibility. However, there is a gap in the literature regarding how these factors combine to affect amphibian stress/immunity. Understanding how these factors affect amphibians, both independently and in combination, is critical for informing regulatory decisions regarding pesticide usage. This thesis investigated the effects of neonicotinoid insecticides on wood frogs (Rana sylvatica [or Lithobates sylvaticus]) and northern leopard frogs (Rana [Lithobates] pipiens). Two immunologically vulnerable stages of amphibian development, tadpoles and metamorphs, were examined. Corticosterone concentrations were assessed after six days of exposure. Corticosterone was reassessed, and blood smears were collected, three weeks post-metamorphosis (R. sylvatica) or immediately following metamorphosis (R. pipiens). Chronic exposure to neonicotinoids affected differential leukocyte counts, indicating stress and possibly increased disease susceptibility. In a follow-up laboratory study, R. pipiens tadpoles were exposed to high concentrations of thiamethoxam or clothianidin in combination with trematode parasites. While neonicotinoids did not affect parasite susceptibility, they affected differential leukocyte counts, possibly due to suppression of the inflammatory response. These results highlight the importance of incorporating stress/immune metrics in ecotoxicology testing, especially given the role of diseases in amphibian declines. I then examined the effects of atrazine independently and in combination with warming temperatures on R. pipiens in a mesocosm experiment. While atrazine alone did not affect tadpoles or metamorphs, atrazine combined with warming to have exacerbated effects on metamorph stress. Furthermore, warming had overarching effects, reducing tadpole locomotor activity, and reduced survival, immunity and increased stress in metamorphs. These findings underscore the importance of incorporating multiple temperatures into toxicity testing and lend insights as to how amphibian susceptibility to parasites/pathogens may be affected by climate change. This thesis provides important insights as to the effects of commonly used pesticides and warming temperatures on amphibian stress/immunity. My findings underscore the need to incorporate more realistic exposure scenarios in ecotoxicity testing and will help inform pesticide regulatory decisions in Canada
The Greco-Roman Historians & Their Geographic Mentalité : Word Embeddings to Investigate the Imagination of Space in Representations of the Early Roman Republic
Get PDFThis thesis explores the concept of "geographic mentalité," how ancient historians conceptualized and understood geographical space, through the application of computational text analysis methods. Using word embedding models, I analyze how Latin and Greek authors from the late Republic through the Empire described cities and places, particularly focusing on central Italian sites currently unknown to archaeology. The model reveals that several undiscovered sites, such as Apina, Sabata, and Scaptia, were discussed using patterns of language closely aligned with mythological references rather than known locations, implying that ancient authors conceptualized these places through cultural and narrative frameworks instead of geographic relationships
Mapping Ecologies of Presence: Connecting Site to Place
No full textThis thesis explores how a place in the east end of Montréal/Tiohtià:ke offers architects a space for pause—not for design solutions per se, but for critical reflection on our site methodologies. Addressing places that exist as vague and in-between, reveals the longstanding colonial, extractivist, and ableist relations to land underlying contemporary notions of third landscapes. Immersion in the site, through events, souped photography, material traces, and interviews, offers a more nuanced understanding of competing and co-existing site processes, providing traces of how bodies and environments come together and change over time. For designers, it is crucial to examine how our understanding and representations of sites reflect the complex social, political, and material realities of places, with the in-between offering a valuable space for pause
Band-aid on a five-inch gash: policy implications of the alignment between Ottawa’s construction of homelessness and lived experience
No full textDespite policy responses from multiple levels of government, homelessness in Canada continues to grow. The construction of homelessness in policy influences the nature of these responses, and incomplete problem constructions can prevent adequate solutions to the issue. This thesis considers the policy implications of how the Ottawa 10-Year Housing and Homelessness Plan's construction of homelessness compares to the lived experience of homeless individuals in Ottawa. Using data from focus groups with individuals experiencing homelessness in Ottawa and an analysis of the Ottawa 10-Year Housing and Homelessness Plan, this study argues that the construction of homelessness contained in policy fails to accurately reflect lived experience due to embedded neoliberal values. Consequently, the proposed solutions reinforce the very structures that sustain homelessness, perpetuating the social control and stigmatization of homeless populations. The findings highlight the need for meaningful inclusion of lived experience in constructing social problems to improve policy responses
Integration of Functional Mock-up Interface with Discrete Event System Specification for Co-simulation of Discrete and Continuous-Time Models
No full textThe Functional Mockup Interface (FMI) is a standardized interface designed for model exchange and co-simulation of dynamic models across various tools. It is an asset for the development of multidisciplinary systems. Integration of this standard with modeling and simulation formalism enhances interoperability and provides opportunities for collaboration. In this thesis, we present an approach for integrating FMI with the Discrete Event System Specification (DEVS). DEVS provides the modularity required for seamlessly integrating the shared model. We proposed a framework for exporting and co-simulating DEVS models as well as for importing and co-simulating continuous-time models using the FMI standard. For the co-simulation of continuous time models, we also implemented continuous time solvers capable of simulating continuous-time dynamics in the DEVS framework. The practical application of this framework is illustrated through two case studies. One case study simulates the Protein-Kinase Transduction process while the second simulates the PID-controlled Unmanned Ground Vehicle