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A Patient-Specific Winston-Lutz System for Multi-Target Single Isocentre Radiotherapy
No full textThis work introduces a novel quality assurance (QA) system for verifying patient-specific radiation targeting accuracy in multi-target, single-isocentre, stereotactic radiosurgery (SRS). A phantom with a 3D array of possible target positions and associated software were developed. Target positions and gantry/couch/collimator angles for the QA test are chosen to correspond to the patient’s SRS treatment plan. Target positions relative to the field centroid are detected using the Hough circle detection algorithm, and the radiation field is detected using image thresholding. Validation against independent software showed agreement within 0.19 mm. Validation using synthetic data yielded targeting errors of at most 0.53 mm, which is within image resolution limits. Field area discrepancies were 2.60% (mean) and 3.33% (maximum) of the expected field size. Multi-target test cases including intentional misalignments were carried out to demonstrate the accuracy and sensitivity of the QA system. This system defines patient-specific machine isocentricity according to a chosen tolerance
Royal Fish, Sea Monsters, and the Great Leviathan: Whales in Seventeenth Century England
No full textThe relationship between humans and whales has been transforming for centuries. This thesis aims to uncover the multi-faceted way in which whales were perceived in seventeenth-century England. The early modern English had varying and sometimes conflicting views of whales, considering them “royal fish,” useful commodities, and preternatural beings. This thesis analyzes the role whales played in legal disputes – particularly in the Crown’s claim to the foreshore, – investigates mariners’ shifting attitudes towards whales during the development of early English whaling, and explores the differing reactions of people ashore to stranded whales. What it reveals is that the tie between humans and whales has always been far more complex and dynamic than a simple predator-prey interaction. This thesis seeks to reinsert whales into our understanding of early modern England, while providing a lens through which we can reevaluate our past and current relationship with these “wonderous” marine mammals
EXPLORING THE ROLE OF SEX, FRAILTY, OR NEUROPATHOLOGY IN THE ANTIDEPRESSANT-ALZHEIMER’S DISEASE ASSOCIATION: A SCOPING REVIEW AND A SECONDARY DATA ANALYSIS
No full textBackground: Depression is a modifiable risk factor of dementia. The antidepressant-dementia association among older adults remains inconsistent.
Methods: Two separate studies — a scoping review and a retrospective study — were conducted. The scoping review assessed whether sex or frailty has been studied as an effect modifier (EM) or confounder of the antidepressant-dementia relationship. The retrospective study assessed whether sex, frailty, or neuropathology modifies the antidepressant-dementia relationship.
Results: The scoping review found that frailty was not explored as a confounder or EM in the literature. Sex was not explored as an EM. Studies examining sex as a confounder differed widely in their methodologies.
The retrospective study found an association between antidepressant use and clinical dementia (odds ratio 2.65, 95%CI: 1.99-3.54). Male sex, frailty, and neuropathologic burden tended to have weaker antidepressant-dementia association, but this was not statistically significant.
Conclusion: More studies are needed to explore potential EMs of the antidepressant-dementia relationship
Phytoremediative Deathscapes: An Ecological Reimagining of Afterlife
No full textThis thesis examines how architecture can rethink the way we care for the earth and the dead through a lens in which death is not an endpoint but a process of renewal within the larger ecological system. Set in Sudbury Ontario’s decommissioned Vale Copper Cliff Nickel Refinery, the project envisions a restorative deathscape that unites the dead, the living, and the landscape. The principles of natural decomposition are applied to the restoration of the post-industrial landscape, nurturing an interconnected system of care that addresses ecological and cultural scars. Phytoremediation and terramation, a process that transforms human remains into nutrient-rich soil, are employed in the project to address industrial pollution and facilitate memorial practices. By merging the care of loved ones with the care of the earth, this project fosters a renewed relationship with the landscape—one akin to gardening, where mourning and regeneration become deeply interconnected
Deceptive Marketing: The Inequality of Gendered Brands
No full textThis research examines consumers' asymmetric perceptions of norm violations associated with gendered, humanized brands, particularly in instances of brand transgression, like deceptive marketing. Building on gender role congruity theory, we hypothesized that consumers would perceive greater norm violations when feminine brands engaged in norm-violating behaviours (deception) compared to masculine brands. A 3 (brand personality: feminine vs. masculine vs. undifferentiated) x 2 (marketing practice: deceptive vs. honest) experiment showed that consumers perceive heightened norm violations when feminine brands engage in deceptive practices compared to masculine brands. This research contributes to understanding asymmetric consumer responses to brand transgressions in the context of humanized brands and highlights essential considerations for marketing strategies related to gendered brands
"Like a Father That I Didn't Have": Constructing Community and Masculinity in the Red Pill Subreddit
No full textThe Red Pill subreddit is an online community on the social media platform Reddit, a community that aims to discuss sexual strategy. Their discussions are framed by their belief that feminism is a manipulation tactic used by women to satisfy their own interests and oppress men. In this study, I analyze the strategies of members on the Red Pill subreddit to decipher what strategies they consider successful, as well as how members reject or accept these strategies. To do this, I conduct a qualitative content analysis of the 30 most popular posts of 2024 from the subreddit. Through my findings I explain the types of interactions members engaged in to identify what content met Red Pill standards, and what was considered unacceptable. I then describe the strategies members perceived as successful, particularly emotional detachment and control. My findings were connected to concepts of masculinity and performance
Exploring Bird Feeding as an Enhancement Method of Bird Biodiversity on Dalhousie University Studley Campus; One Seed at The Time
No full textEnvironmental Problem Solving II: The Campus as a Living Laboratory Student PapersGlobally, anthropogenic land alteration and exploitation have introduced significant stressors to avian populations, leading to substantial declines. Such stressors include high mortality rate and significant decrease in food availability and biomass. Birds provide essential ecosystem services by enhancing biodiversity, acting as natural seed dispersers and pollinators, and contributing to mental well-being by fostering a connection to nature. University students, in particular, benefit from bird diversity through stress reduction and increased productivity. However, efforts to enhance bird biodiversity, such as bird feeder implementation, are lacking on university campuses in urban areas. In this study, optimal bird feeder locations were assessed for the Pileated woodpecker (Dryocopus pileatus), Baltimore oriole (Icterus galbula), and Evening grosbeak (Coccothraustes vespertinus), which were identified as suitable species for attraction to Dalhousie University’s Studley Campus. We collected tree data and completed a literature review to determine feeder needs and location requirements for each bird species, with an associated maintenance plan and cost analysis. The Baltimore oriole was found to have the most suitable areas for bird feeders, while the Evening grosbeak had the least. Similarly, the Baltimore oriole had the least expensive feeder and food requirements, whereas the Evening grosbeak had the costliest. When summarizing maintenance and costs, volunteer labor was identified as the most affordable and feasible option, with an average contribution of three hours per week through the year. The Baltimore oriole and Pileated woodpecker had similar suitable areas for bird feeders, highlighting feeder location preferences in mixed forest with large trees (DBH>65cm), which were areas found behind the Killiam library and Student Union building. Local habitat features such as these have been found to play a significant role in attracting avian species to urban areas. Several considerations should be made, including proximity to natural and urban features for invasive species management, and proper feeder maintenance including regular cleaning to avoid the spread of potential avian diseases. To maximize conservation benefits and biodiversity enhancement, universities should implement strategic habitat suitability-based feeder placement, regular maintenance plans, and volunteer-based monitoring programs to enhance bird biodiversity Dalhousie University Studley Campus.
Key Words: Habitat Suitability; Urban Biodiversity; Bird Feeder; Pileated Woodpecker; Baltimore Oriole; Evening Grosbeak; Disease Transmissio
The Effect of Lignin on the Mechanical, Thermal, and Morphological Properties of Carboxymethylcellulose/Pectin Bio-composite Films for Food Packaging Applications
No full textThis thesis work involves using sustainable materials to fabricate food packaging films, which aim to replace petroleum-based films.Biopolymers have been regarded as a promising alternative green material to curb the environmental and ecological concerns caused by the increased use of petroleum-based polymers in flexible packaging films. The current work incorporates kraft lignin and deep eutectic solvent (DES; propionic acid and urea in a 2:1 molar ratio) into a carboxymethylcellulose (CMC)/pectin bio-composite matrix. Three sets of films were prepared and analyzed for tensile strength (TS) and elongation at break (EB), water vapour permeability (WVP), film composition, surface morphology, and thermal properties using a force tester, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The first set of films was prepared to compare biopolymer films with varying DES loadings. The second set of films was prepared using a mixture design of experiments (DoE) and response surface methodology to explore varying film compositions with CMC, pectin and lignin as variables. The experimental validation of TS and EB confirmed that the prediction model was valid. The third set of films was prepared to evaluate one promising composite film formulation in detail by comparing the original formulation to similar formulations without lignin or lignin-DES. The formulation most suited for packaging applications (within the composition range studied) consisted of CMC/pectin/lignin weight ratio at 1.213 g/0.737 g/0.05 g per 2 g w/v (dissolved in 100 mL milli-Q water) with 1.5 g DES. In general, the DES acted as a green plasticizer, and lignin exhibited a plasticizing effect at low loadings. The as-prepared samples provide a promising low-cost approach for fabricating biodegradable plastic films from waste materials and have potential applications in food packaging
Recycling City: Safe Spaces for Informal Recyclers
No full textHalifax is undergoing rapid urban transformation, with a population growth rates of 4.5% in 2022. In response, a recent zoning amendment was enacted, allowing for developments in key locations of the Halifax Peninsula to reach heights of up to 40 stories. This threatens the livelihood of a traditionally marginalized sector of the city; people who engage in informal recycling, as a key piece of recycling infrastructure, the Clifton Recycling Centre, lies within one of these zones, putting it at risk of redevelopment. This thesis investigates how architectural interventions can create safe spaces for recyclers, legitimizing their roles as waste diverters and reinforcing their right to the city. Utilizing critical cartography and case study analyses of groups advocating for the rights of recyclers across North America, this research draws on existing systems to position architecture as a tool of spatial justice that can foster inclusivity, promote legitimization and support the informal recycling economy in Halifax