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Direct Measurement of Resonance Properties in 23Mg(p,γ)24 Al Reaction occurring in Classical Novae using the DRAGON Recoil Separator and a Hybrid Array of Gamma Detectors
Full text link1 online resource (1 unnumbered, ix, 90 pages) : illustrations (some colour), graphs (some colour)Includes abstract and appendix.Includes bibliographical references (pages 80-83).Nucleosynthesis in classical novae refers to the process of creating new atomic nuclei during the thermonuclear explosion on the surface of a white dwarf in a binary star system. This process is driven by rapid nuclear reactions in the hydrogen-rich material accreted from the companion star. When critical thresholds are reached, thermonuclear fusion ignites explosively. This intense reaction not only converts hydrogen into helium but also triggers a series of proton capture reactions that produce heavier elements up to Calcium. Classical novae are significant contributors to the cosmic abundance of certain isotopes, such as 13C, 15N, and radioactive 22Na and 26Al. Observations of these elements in the spectra of the ejected material help astrophysicists study the processes governing stellar evolution and nucleosynthesis.
The main objective of this research is to study the 23Mg (p, γ)24Al reaction rate at the classical nova temperatures of 0.2 to 0.4 GK. The goal is to pursue a new measurement of the key astrophysical resonance at Ecm ~480keV which couples the DRAGON recoil separator to a hybrid array of Lanthanum Bromide (LaBr3), Cerium Bromide (CeBr3) and Bismuth Germanate (BGO) detectors for γ-ray detection. This experiment uses radioactive 23Mg beam with an energy chosen such that all published measurements of the resonance energy are contained within the equilibrium pressure region of the windowless H2 gas target. The strength of the ~480keV resonance was determined from the singles yield of 24Al recoils detected at the DRAGON focal plane. This newly determined resonance strength is incorporated into NuGRID nova simulation codes for nova model which determines its impact on nucleosynthesis in classical novae.</p
High-velocity stars ejected from globular clusters : candidates from Gaia DR3
No full text1 online resource (xi, 119 pages) : graphs (some colour)Includes abstract and appendix.Includes bibliographical references (pages 89-98).Globular clusters lose stars through a variety of mechanisms, some of which eject stars with a considerable velocity. The velocities and rates of stars ejected through different mechanisms are dependent on cluster properties such as black hole content and binary fraction, thus observations of high-velocity stars around globular clusters can be used to constrain those properties. In this work, we use proper motions from Gaia Data Release 3 to identify high-velocity star candidates in the regions around a large number of Milky Way globular clusters. We focus our analysis and discussion on the clusters with the most significant excess of high-velocity candidates in our sample, primarily NGC 3201 and NGC 6101. We estimate that the contamination of our sample around these clusters appears to be low, however the dynamical models of NGC 3201 we examine predict far lower rates of ejected stars than implied by our sample of high-velocity candidates
‘The left behind places’ : a Burin Peninsula case study on the aftermath of the cod fishery collapse
Full text link1 online resource (108 pages) : colour mapsIncludes abstract.Includes bibliographical references (pages 100-108).The cod fishery collapse, which led to the moratorium in 1992, signaled the end of the 400-year cod fishery in Newfoundland. By contextualizing the resource industry changes experienced by many rural communities in Canada in the 1980s, 1990s, and early 2000s, this thesis explores the effects and benefits of incorporating significant community input in decision-making processes during periods of acute crisis. A focus on the response by impacted fishers on the Burin Peninsula to changing cod fishery management approaches, and the subsequent cod collapse indicates that many local people remain frustrated at how it was handled and are concerned for the future of their home communities
What's on the menu, I'm hungry! a comparative analysis of targeted prey types species of Neanderthals and anatomically modern humans, and their dietary breadths
Full text link1 online resource (iii, 70 pages)Includes abstract and appendices.Includes bibliographical references (pages 59-63).Neanderthals and Anatomically Modern Humans (AMH) exhibited distinct prey selection
that reflect their ecological adaptations and resource exploitation. This research examines the
dietary breadth of these hominins by analyzing faunal assemblages from 44 archaeological sites across Western Europe. Using zooarchaeological and taphonomy data, prey selection patterns were compared between Neanderthal, AMH, and mixed occupation sites with a focus on coastal versus inland environments. Statistical analyses, including Mann-Whitney U and Kruskal-Wallis tests, were conducted to assess significant differences in prey species selection, trophic level consumption, and prey body size. Results indicate that Neanderthals had a more specialized diet, primarily targeting terrestrial mammals, whereas AMH displayed a broader dietary range, including increased exploitation of marine resources at coastal sites. While Neanderthal prey selection varied significantly between coastal and inland environments, AMH dietary strategies remained relatively stable across different landscapes. Additionally, Neanderthals preferentially targeted larger-bodied prey, whereas AMH focused on herbivorous species but showed no strong preference for prey size. This research provides critical insights into the ecological adaptations of Neanderthals and AMH, emphasizing the significance of environmental context in hominin foraging strategies. The findings contribute to ongoing debates regarding the flexibility and resilience of early human populations in response to changing landscapes and resource availability
Structural evolution of galaxies. Size-mass relations and environmental effects in rest-frame ultraviolet and optical wavelengths since seven billion years ago
No full text1 online resource (xix, 321 pages) : colour illustrations, charts (some colour), graphs (some colour)Includes abstract and appendices.Includes bibliographical references (pages 266-321).This dissertation investigates the size evolution and structural properties of massive (∗ > 109.5⊙) star-forming (SFGs) and quiescent galaxies (QGs) at < 1, using the CLAUDS+HSC imaging in rest-frame UV (3000Å) and optical (5000Å) wavelengths. The first part of this dissertation analyzes 16,000 SFGs and 5,000 QGs in the COSMOS field, modeling their light profiles with single-component Sérsic fits. Size-mass relations show galaxies are more extended in UV than optical. SFGs with a fiducial mass of 5×1010⊙ grow by 20% (UV) and 30% (optical) since z∼1. Redder SFGs are smaller, more concentrated, and increase in fraction over time, suggesting the emergence of bulges driving their size evolution. Up to 20% of QG size growth is due to recently quenched “newcomers,” although the dominant contribution comes from minor mergers and accretion. The second part examines environmental effects on 86,000 QGs in the field and 1,000 QGs in the cluster cores across 18.6 deg2. QGs are larger in UV than optical, with a stronger difference in the field than in cluster cores. Cluster QGs are systematically smaller, especially in UV, but grow as rapidly as field QGs. This growth is driven by the accretion of larger field QGs and quenched newcomers. The third part performs bulge+disk decomposition of 44,000 SFGs and 34,000 QGs. Disks are larger than bulges, particularly in UV, while bulges are smaller in UV than optical. Bulge sizes grow faster than disks for both populations, with wavelength-dependent growth rates. These results indicate growth of bulge sizes plays a dominant role in the structural evolution of SFGs, while minor mergers and newcomers shape QG morphologies. Collectively, this work elucidates how internal processes (bulge formation) and external factors (environment, accretion) drive galaxy evolution, with UVoptical differences highlighting distinct structural and evolutionary pathways.</p
Survival and regrowth : assessing red oak recovery after the 2023 Shelburne Wildfire
Full text link1 online resource (57 pages) : colour illustrations, colour maps, graphs (some colour)Includes abstract and appendix.Includes bibliographical references (pages 54-57).Wildfire disturbance events are increasing in both frequency and intensity across Canada. Historically, due to their proximity to the ocean, Maritime natural disturbances have been limited primarily to strong wind events such as hurricanes. However, climate models suggest an increased prominence in these provinces experiencing fire activity. Between May and June of 2023, three major wildfires were reported in Nova Scotia, affecting over 25,000 hectares of land. The biggest of which was located in Shelburne County. By the time this fire was completely extinguished, it had become the biggest wildfire in recorded Nova Scotian history. There is a need to understand how wildfire events affect the intricate dynamics of forest succession and forest health. Northern red oak (Quercus rubra) is the only native species of red oak found throughout Nova Scotia and possesses natural traits that make it more resistant to the damage caused by wildfire events. This study examined whether the natural traits of the red oak species yielded any favourable results on the survival and regrowth rates of red oak during secondary succession. Variables studied included char height, species density, and coppice regrowth. These variables were compared against red maple (Acer rubrum) and further towards plots of different fire intensities. The dead count for
both species increased throughout the fire plots. When compared to different levels of fire intensity, greater fire intensity had a smaller effect on the dead count of red oak as compared to red maple. The fire plots not only were shown to have more coppice growth for both red oak and red maple, but also fire plots of greatest intensity were shown to have the most red oak coppice growth
Environmental lipidomic baseline survey of the Scotian Slope, Atlantic Canada
Full text link1 online resource (xvii, 209 pages) : illustrations (some colour), colour maps, charts (some colour), graphs (some colour)Includes abstract and appendices.Includes bibliographical references (pages 23-31, 48-49, 80-88, 141-150, 179-181, 205).This study is an environmental baseline survey using lipidomic techniques and various lipid compounds as biomarkers for living and dead microbial cells that lived in or were transported to Scotian Slope shallow marine sediments. Distinct stratigraphic patterns were observed for individual lipid classes in the upper 9 metres of sediment below sea floor. Archaeal lipids were found to be originating from the both the water column and ocean floor sediments and increase by bathymetric depth, while distribution of bacterial and eukaryal lipids reflected a high contribution of heterotrophic bacterial communities, decrease by bathymetric depth. The distribution of various compound classes varies systematically with sediment depth,
resulting in four stratigraphically overlapping archaeal lipidomes, seven for bacterial lipidomes, as well as distinct MK lipidomes, reflecting ~26,000 Kyr of changing water column loading and in situ sedimentary production from benthic communities
Nest composition of European Starlings (Sturnus vulgaris) : an investigation into feather and anthropogenic material content
Full text link1 online resource (36 pages) : graphsIncludes abstract and supplemental information.Includes bibliographical references (pages 25-28).Avian nests provide shelter for eggs and nestlings from weather and predators, and can be
modified to satisfy the demands of different climates. Nests contain a mixture of natural
substances, including grasses and feathers from other species and sometimes include
anthropogenic materials such as plastics. White feathers have been found to be positively linked with hatching success in a variety of passerine species. European starlings (Sturnus vulgaris) are an urban-thriving, cavity-nesting songbird. They lay two clutches of eggs in a breeding season (early season: April; late season: June), and males incorporate feathers and anthropogenic materials (i.e., litter) into their nests. Litter may be used as decoration to attract a female. My first objective was to compare total nest weight and feather weight/type (insulative vs. pennaceous) between early- and late-season nests. I predicted that early-season nests would be heavier and contain both more total feathers and more insulating feathers than the late-season nests because it is colder. Another objective was to determine whether a positive relationship exists between the amount of white feathers and hatching success. Finally, my third objective was to determine if the amount of litter a male incorporates into his nest differs between the early- and late-season or increases as he ages (examined over time as a longitudinal study). I collected and dissected 32 starling nests from the Saint Mary’s University campus in Halifax, Nova Scotia, Canada in 2024. Contrary to my predictions, early-season nests were not significantly heavier than late-season nests, and more insulating feathers were present in lateseason nests than early ones. Surprisingly, the amount of white feathers in nests was negatively correlated with hatching success. Finally, anthropogenic material did not differ between the early-season and late-season nests, and 16 individual males did not incorporate more litter into their nests as they aged
Evaluating the civilian oversight of law enforcement process in Nova Scotia
No full textThis master’s thesis evaluates civilian oversight of law enforcement in Nova Scotia, focusing on the Office of the Police Complaints Commissioner (OPCC) and the Police Review Board (PRB). Using an inputs–processes–outputs–outcomes framework, it examines their effectiveness in promoting accountability, procedural justice, and public confidence. Central to the analysis is Carrie Low v. Nova Scotia Police Complaints Commissioner, which exposes systemic weaknesses, including limited investigative independence, insufficient resources, procedural delays, and barriers to complainant engagement. Drawing on legislation, institutional documents, interviews, and judicial decisions, the study highlights structural obstacles that hinder timely and fair outcomes. Findings emphasize the need for reforms: greater independence from the Department of Justice, expanded investigative powers, enhanced transparency, and stronger complainant support. Such changes are crucial for building an effective oversight system capable of fostering public trust and ensuring meaningful accountability in policing
The impact of the bond between survivors of intimate partner violence and larger companion and farmed animals
Full text link1 online resource (150 pages) : colour illustrationsIncludes abstract and appendix.Includes bibliographical references (pages 140-149).Survivors of intimate partner violence experience numerous challenges and barriers that
impact their safety decision-making, including considerations regarding the interspecies
members of their families. My study focused on gathering survivor voices as well as the voices of service providers to offer insight as to how the bond between survivors and their farmed, larger companion, and working animals impacts the survivor’s safety decision-making. The key findings of this study highlight that the bonds between survivors and these types of animals are positively emotionally impactful and this bond significantly impacts survivors’ decisions regarding safety. Survivors who do leave the relationship have to find solutions for the care of these types of animals or permanently end the relationship with their animals. Overall, there is a need for a multi-layered solution with multiple options for survivors and all types of animals to support survivors in maintaining their bond with their animals in these circumstances