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Bird and Bat Diversity and Abundance in Agroecosystems in Relation to Drainage Hedgerow and Landscape Structure
No full textHedgerows are common semi-natural linear features along agricultural drainages in temperate agroecosystems. Two important variables likely to affect diversity within hedgerows include hedgerow structure and landscape structure. I hypothesized that hedgerows that are taller, wider, and more variable in height, and landscapes with smaller fields and higher forest amount, will support higher diversity within drainage hedgerows by providing more habitat. I used point counts of forest and shrub-edge-associated birds and ultrasonic recordings of bats along drainage hedgerows in eastern Ontario to test my hypotheses. Overall, I found that drainage hedgerow height was positively associated with higher biodiversity for birds and bats. Width and variation in height were also important depending on the response considered. With respect to landscape structure, edge-associated species generally responded positively to smaller field sizes. My results show that structurally complex drainage hedgerows and smaller fields provide valuable habitats for birds and bats in agroecosystems
Poor Black Woman. The Surveillance of Class, Race, and Gender in Canadian Urban Planning: An Autoethnography
No full textThis thesis unpacks how Ottawa Community Housing Corporation (OCH) has reorganized its parking practices to further surveil predominantly racialized and precarious individuals in their communities. Using a mixed-methods, ethnographic approach that includes autoethnography, participant observation, interviews, and online archival work, I argue that this OCH parking regime is an extension of historical urban planning processes in Canada. It reinforces racialized dispossession and oppression, and that this parking system feeds racialized bodies into broader global surveillance systems. Using class, race, and gender, I provide a historical analysis of how each identity we intersect with increases the likelihood that we will not only live in poverty but become entrapped in systems that work closely together to survey, control, and punish us based on social markers
2D LIDAR and mmWave-Based Mapping and Localization for Indoor Navigation
Get PDFThe use of wearable devices has grown exponentially, with applications ranging from improving efficiency to localization and mapping for situational awareness. Yet commercial devices are unavailable for emergency response. Previous researchers at the BioMechatronics lab in partnership with the Oshawa fire department developed a low-cost wearable for accurate localization and mapping of firefighters. The wearable was equipped with a 2D-LIDAR, IMU, and mmWave sensor, but available software failed because the user's gait corrupted the mapping and environmental conditions were inappropriate for some sensors. This thesis proposes a solution to enable accurate mapping with 2D-LIDAR subjected to gait-induced out-of-plane motion. It also introduces two three-degrees-of-freedom localization algorithms using a mmWave sensor to enable localization in environments where LIDAR performance is degraded. These localization algorithms are then extended to six-degrees-of-freedom to fully capture the wearable's movement. Together, these advancements pave the way for reliable adoption of wearable devices by emergency responders
Exploring Enhancements to Intimate Partner Violence Risk Assessment: Leveraging Insights from Decision Tree Analyses
No full textIntimate partner violence (IPV) represents the largest proportion of violence in most women’s lives, and it affects millions of individuals and families across Canada and around the world. Research indicates that current IPV risk assessments do not meaningfully outperform general-violence risk assessments. The purpose of the current study was to improve IPV risk assessments, specifically, to better understand whether IPV specialists and generalists are different and, additionally, to determine the extent to which IPV-salient risk factors should be considered, or differently weighted, in predicting recidivism. The sample (N = 911) included men who were referred to outpatient treatment or recruited from an employment agency between 1976 and 1994. Using recidivism data obtained in 1999 for a subset of 343 cases, more than 700 simple and composite potential predictor variables were examined. Approximately 53% of men were identified as IPV specialists, and 31% recidivated. Using classification and regression tree (CART) analyses, 22 variables were identified as differentiating between specialists and generalists, and 13 variables were found to differentiate between recidivists and non-recidivists in the training samples, respectively. A random forest procedure was used to reduce the pool of variables, resulting in trees with overall classification accuracy of 72.1% in the specialization model and 62.0% in the recidivism model. The models generalized with some success to the testing samples. Finally, an assessment was made of the weighting of IPV-salient to general-violence risk factors. When considered separately, the IPV-salient and general-violence models had moderate (area under the curve [AUC] = .689) and small (AUC = .598) effect sizes, respectively. When both models were included, together they had a large (AUC = .762) effect size. Within this model, the optimal balance between the two types of factors was equal. The methods and results of this dissertation will support the improvement and future development of IPV risk assessments. The results add to the growing body of evidence that indicates CART analyses and other types of machine learning may be highly useful tools in future risk assessment development. Limitations and future directions of this research are discussed
Decline of migratory monarch butterflies during their fall migration in North America
No full textThe migratory population of monarch butterflies in North America has significantly declined over the past few decades, leading to their classification as an endangered species in Canada. Scientists have identified two major groups of threats responsible for this decline: those affecting monarchs during migration and those affecting them during the breeding season. In this study, I investigated two threats potentially impacting monarchs during their fall migration: the range expansion of winter- breeding monarchs and roadkill during fall migration. Winter-breeding monarchs in North America do not migrate to overwintering areas and continue breeding during the winter in regions with a suitable climate and available non-native milkweed. These monarchs carry a higher burden of the Ophryocystis elektroscirrha parasite, which can increase the infection rate among the offspring of migratory monarchs that interact with them. In the first project in this thesis, I used species distribution modeling to estimate the current distribution of winter-breeding monarchs across North America and projected their potential future distribution based on different climate change scenarios. In the second project, using community science data and accounting for sampling bias, I mapped the distribution of migratory monarchs in late summer before they start their fall migration. Understanding the pre-migration distribution of monarchs was essential for my third project, where I estimated the average probability of roadkill for migratory monarchs starting their fall migration from any location across their distribution. Even under the most optimistic scenarios, my results suggest a 98% and 22% range expansion by 2100 for western and eastern winter-breeding monarchs, respectively. Additionally, my results show that the average estimate of roadkill probability for monarchs during fall migration is 99.5%. My research sheds light on the extent to which these two migration-related threats affect monarchs and helps decision-makers identify priority areas for stopping the spread of non-native milkweed. Furthermore, these findings assist in making informed decisions to recover the population of migratory monarchs by highlighting the high roadkill risk they face during migration
Novel Highly Brominated Methoxylated Contaminants: Exposure, Terrestrial Sources, Bioaccumulation, and Fate in a Great Lakes Avian Model Species
No full textBrominated flame retardants (BFRs) are a large class of highly persistent and bioaccumulative chemicals with the potential for adverse effects in wildlife exposed to them. This thesis investigated the distribution of polybrominated diphenyl ethers (PBDEs) and several non-PBDE halogenated FRs (HFRs) throughout maternal herring gull tissues (adipose, liver, muscle, red blood cells, plasma) and their eggs (yolk and albumen), and estimated the extent of their in ovo depuration. Methoxylated polybrominated diphenoxybenzenes (MeO-PB-DiPhOBzs) are a class of what are believed to be degradation byproducts recently discovered in herring gull egg homogenate samples collected as part of the annual Great Lakes Herring Gull Monitoring Program. MeO-PB-DiPhOBz tissue distributions and in ovo transfer rates were similarly determined and compared to PBDEs and non-PBDE HFRs. This thesis also conducted a systematic literature review on the metabolism of BFRs in wildlife species, with a focus on emerging and novel (E/N)BFRs. Deficiencies in in vitro assay quality control and assurance practices were highlighted, as well as a paucity in studies conducted on E/NBFRs with most focused on legacy BFRs (i.e., PBDEs and hexabromocyclododecanes). The unmethoxylated form of MeO-PB-DiPhOBzs are reported here for the first time in any environmental medium, present in soil collected from Channel Shelter Island (CSI), Lake Huron. MeO-PB-DiPhOBzs were also measured in the soil and herring gull regurgitant collected on CSI, suggesting that they are bioaccumulative contaminants to which the gulls are exposed, rather than metabolic products produced within them. Lastly, novel in silico methodologies were developed and evaluated to model the CYP-mediated biotransformation of MeO-PB-DiPhOBzs. Five distinct potential binding modes of the CYP3A4-MeO-PB-DiPhOBz complex were predicted, while CYP1A binding modes were limited likely due to their strong preference for coplanar ligands
Discrete Element Analysis of Thermomechanical Behavior of Frozen Granular Soils
No full textA significant part of Earth's surface is covered by frozen soil, posing challenges in mechanical properties which is affected by temperature, strain rate, and pressure, and is exacerbated by global warming. Traditional approaches using continuum mechanics may overlook particle interactions inherent in soil. Frozen soil lab tests face equipment limits, but computational advances offer the discrete element method (DEM) as a modeling alternative. Using DEM-based YADE software, we calibrated parameters to model frozen sand, achieving agreement with stress-strain curves and exploring pressure-dependent shear strength across temperatures. Our model includes an improved contact model considering rolling resistance between particles, enhancing volumetric behavior and addressing spherical shape oversimplification, accommodating real-world diversity. Aligned with shear strength data from triaxial tests, our numerical model acts as virtual experiments, exploring frozen soil response to complex loading paths. Numerical triaxial tests with temperature variations deepen understanding of frozen sand behavior under changing thermal conditions
Ecological Thresholds: Tracing Fish Journeys in and Beyond Industry Expansion
No full textThe Pacific Northwest fishing industry was a prominent economic force from the late 19th to mid-20th century. After local resources had been exhausted, canneries were typically abandoned, leaving behind a legacy of economic hardship and environmental contamination. This thesis reflects on the past and present conditions of such sites through a curated exhibition that engages with more-than-human and multi-species approaches within the environmental humanities while considering the methodological implications for architecture. A series of explorations in storytelling take place through illustrative printmaking, put forward as a useful technique to parse the impacts of industrial fishing — both on fish and people. The work challenges the thresholds between architecture and ecology in efforts to contemplate sites with complex and difficult histories
A Critical Examination of Efficiency Within Competition Law in Canada and Globally
No full textSince the rise of the Chicago School in the 1960s, there has been a longstanding belief held by many economists and policy makers that competition law should aim to promote economic efficiency. This belief has played an important role in shaping competition law and policy. The goal of the three essays here is to explore and critically evaluate the stance that the sole or primary aim of competition law should be to promote economic efficiency. The first two essays examine efficiencies defenses for mergers, which are provisions common within many competition laws that prescribe how efficiencies from mergers should be reconciled against merger harms. They are an ideal subject for exploring the dissertation topic because they reflect real-life decisions made by lawmakers on whether and how to prioritize the pursuit of efficiency over other potential objectives of competition law. The first essay investigates how lawmakers have attempted to tradeoff merger efficiency gains against merger harms and whether these attempts have evolved over time with changing economic and political realities. Though a legal text analysis of all efficiencies defenses in force up to 2010, it finds a longstanding pluralism in how lawmakers reconcile efficiencies and harms, challenging the notion of a single best practice for integrating efficiencies into merger review on a legislative level. Through econometric methods, the second essay explores whether efficiencies defences actually produce greater economic efficiency and productivity within an economy. The results show an ambiguous relationship between efficiencies defenses and total factor productivity (TFP) growth. It finds that the amount of resources nations devote to competition law enforcement is a key determinant of TFP growth, more so than the content of the law itself. The third essay steps back from efficiencies defences to engage the debate on whether competition law should aim to promote a more equal distribution of income across the economy, or if that responsibility should be delegated to the tax and transfer system. Using descriptive empirical methods and microsimulations from Statistics Canada’s Social Policy Simulation Database/Model (V.30), the study posits a novel argument for retooling competition law to address income inequality
Facts, Fallacies, and Frames: Exploring the Nexus Between Political Decision-Making and Counterterrorism Resource Allocation
No full textThis dissertation is about political decision-making and counterterrorism resource allocation. Why have Canada and the United States allocated more resources to countering Islamist-inspired terrorism than right-wing extremism, even though the latter has committed more attacks and caused more fatalities since September 11, 2001? Why do political leaders prioritize some threats over others? What is the role of the public service in decision-making? And how do various actors within the national security apparatus – especially those of different generations – interpret the current threat landscape? To answer these questions, this dissertation challenges the rational-utility model and tests three counter explanations: (1) political self-interest, (2) path dependence/bureaucratic inertia, and (3) framing theory. Using a sample of 35 lethal violent extremism attacks between 1995 and 2021, hundreds of open-sourced texts, a variety of quantitative techniques, and 30 original interviews conducted with current and former public servants who work(ed) in the Canadian and US intelligence and security (I&S) community, the results suggest that the answer is multicausal. In addition to the tested theories, political leaders rely heavily on party considerations, high fatality events, symbolic attacks, international threat considerations, and mass and social media influences. The findings also affirm that public servants play an important role in shaping the policy agenda and that deep, albeit shrinking, cleavages persist between the various departments and agencies working in the I&S community