14589 research outputs found
Sort by
Testing the ergodicity of star formation within galaxies
Get PDF1 online resource (xiii, 112 pages) : colour illustrations, graphs (some colour)Includes abstract and appendix.Includes bibliographical references (pages 104-112).Part of our understanding of how galaxies evolve is based on individual evolutions inferred
from population trends. In its strictest form, this approach implicitly assumes that the star formation properties of galaxies exhibit ergodic behaviours, such that the time averages of individual galaxies are equivalent to the average of the population at any given time. In this thesis, we analyze the validity of this assumption on simulated galaxies modelled after observed ones. We find that galaxies without stellar wind feedback are able to match observations and do not, in general, follow strictly ergodic star formation histories. Partial ergodicity is presented in an astronomical sense for the first time, in which subsets of galaxies exhibit time evolution broadly similar to ensemble averages when averaged over, and is observed in the modelled galaxies. Future studies are needed to include the impact of mergers, alternative feedback and stellar evolution models, and ideally a larger sample
Commercial changes and their larger context in a gentrifying neighbourhood : tracking the transformation of Halifax, Canada’s North End
Get PDF1 online resource (vi, 60 pages) : colour illustrations, colour mapsIncludes abstract.Includes bibliographical references (pages 56-60).The North End of Halifax has witnessed drastic changes to its urban landscape since the
beginning of this millennium. Once a historically low-income neighbourhood, the North End now attracts a more affluent demographic of both residents and tourists. Development in the area has increased alongside an influx of new high-end stores, consequently altering the neighbourhood’s streetscape. By analyzing commercial change between 2009 and 2022, this thesis argues that the retail landscape contains valuable evidence of the tensions brought on by gentrification in the North End. To document retail change over the 13-year period, six primary retail streets are investigated through the use of Google Street View imagery. Classifying establishments in both years of study showed that retail gentrification in the North End has been primarily driven by the up-zoning of the neighbourhood, specifically through the introduction of new, mid- to high-rise, mixed-use buildings. Stores that target a demographic with a lower socio-economic status have
notably decreased since 2009, while expensive retailers have increased. It is suggested that if governmental action is not taken to address these implications, the North End could soon cease to have any affordable commercial options
Junkie or patient? media’s portrayal of opioid harm reduction strategies in Nova Scotia
Get PDF1 online resource (54 pages)Includes abstract and appendix.Includes bibliographical references (pages 45-53).Safe supply programs rolled across Canada amidst two public health emergencies: the opioid crisis and COVID-19 pandemic. Earlier research demonstrated safe supply’s efficacy, but confusing messages rooted in a history of racism, criminalization and stigmatization limited access to this life saving program. Harm reduction interventions reduce mortality and improve health outcomes for people who use substances. Criminalization confuses messages surrounding treatment; creates an unsafe illegal market; and fails to eradicate substance use in Canada. Media plays an influential role in shaping public perceptions. This study describes volume, content and themes from Nova
Scotia news media sources that discuss safe supply between 2018 and 2022. Searches of three English-language news media sources from Nova Scotia identified 41 articles, coded for type, tone, topic, harm reduction intervention and thematically analyzed. Volume of coverage increased over time, which coincided with the COVID-19 outbreak and implementation of safe supply programs. Changes in narrative framing and use of stigmatizing language were also observed. No longer understood as a political or criminal issue, Nova Scotia news media content frames safe supply as a health and social justice issue. News media sources in Nova Scotia are not directly contributing to the stigmatization of people who use substances
Changes in adult Atlantic salmon (Salmo salar) run timing in the Miramichi River, New Brunswick, in relation to river temperature and discharge rates over seven decades
Get PDF1 online resource (vi, 64 pages) : maps (some colour), charts (some colour), graphs (some colour)Includes abstract and appendix.Includes bibliographical references (pages 54-62).Atlantic salmon (Salmo salar) is a culturally, economically, and ecologically important species in Eastern Canada. Populations have been declining in recent decades, which can have negative implications for livelihood, ecosystems, and local tradition. Ecological factors associated with climate change in aquatic systems including temperature and river flow can alter the upstream migration behaviour of adult salmon. River entry during upstream migration for spawning, or “run timing”, is a critical life history event for this species. This project found that run timing has significantly changed in the Miramichi River between 1952-2021. To investigate whether this change is associated with ecological factors in freshwater, I examined the relationship between freshwater environmental predictor variables – temperature and discharge rate – and Atlantic salmon entry to the estuary. Unlike previous work on smaller freshwater tributaries, there were no strong relationships found between entry to the estuary from the ocean and freshwater variables
Conflicting edge influence on herbaceous species in open areas vs. underneath oak trees in forest fragments in Iran
Get PDFSubmitted versionSince the type of forest influences vegetation patterns from the edge-to-interior forest, site-specific edge studies are needed but there have been few studies in open-canopied forests such as oak savannahs. Our objective was to compare patterns of herbaceous plant diversity along the forest edge-to-interior gradient between open areas and underneath oak trees in the Zagros Forest in Iran. We established eighteen transects from the forest edge to the interior in small and large forest fragments to sample herbaceous species in five 0.25 m2 quadrats at 1 m intervals from the base of the tree to the open area at different distances from the forest edge. We analyzed the data using randomization tests for edge influence and generalized linear mixed models. Edge influence had a positive effect on herbaceous species richness and diversity underneath oak trees but a negative effect in open areas. At forest edges, species richness and diversity significantly decreased from the tree base toward open areas, but exhibited the opposite pattern away from the edge. Edge influence extended up to 50 m from the forest edge to the interior. Our findings highlight the importance of considering forest type and stand heterogeneity when studying edge influence on plant diversity. Our results show that edge studies are needed for specific forest types, particularly in heterogeneous landscapes, to ensure appropriate conservation of species diversity. We recommend establishing a 50-m buffer zone along edges in the Zagros Forest in Iran to minimize negative edge influence on herbaceous plant diversity.</p
Limited influence from edges and topography on vegetation structure and diversity in Atlantic Forest
Get PDFPublisher versionAlthough Atlantic Forest is diverse and heavily fragmented, little is known about the impact of edges created from fragmentation on forest structure and plant diversity. Our investigation of vegetation at agricultural edges aimed to determine edge width, to compare effects of edge influence and topography and to assess patterns of diversity. We collected data on forest structure, plant groups, plant families, and vertical vegetation structure in 2 × 2 m contiguous plots along 250 m transects across the edges of 24 fragments approx. 70 km west of São Paulo, Brazil. We used randomization tests to estimate the magnitude and distance of edge influence, generalized linear mixed models to assess the effect of topography, and wavelet analysis to evaluate spatial patterns. Although there was evidence of edge degradation (lower diversity and cover of most plant groups compared to interior forest) and edge sealing (abrupt changes at the edge particularly for leafy vertical diversity), edge influence did not extend very far with a distance of edge influence of 20 m or less for most variables. Less extensive edge influence compared to other tropical forests was not explained by topography (slope) but could be due to more extensive fragmentation and land use history. The use of multiple approaches to studying forest edges provided complementary information to improve our understanding of the structure of anthropogenic edges in Atlantic Forest. Signs of edge degradation suggest that edge influence should be considered in conservation planning even though edges are narrow
Wetland Alteration Application Supplemental Report: Muddy Pond Wetland, Waverley, Nova Scotia, PID 40104069
No full textSaint Mary’s University, Dynamic Environment & Ecosystem Health Research Group1 online resource (73 pages) : colour illustrations, colour mapsIncludes appendices
Imaging pathological stomach tissue using polarization second harmonic generation microscopy
Get PDF1 online resource (70 pages) : illustrations (chiefly colour), colour charts, graphsIncludes abstract and appendices.Includes bibliographical references (pages 59-66).Collagen is one of the main macromolecular components in the extracellular matrix
(ECM), and its structure undergoes changes during cell differentiation and cancer progression in the tumour microenvironment. The main goal of the current study was to determine if polarization second harmonic generation (PSHG) analysis can be used to distinguish collagen structures in pathological from normal stomach tissue, and if it can be used to characterize the varying levels of adenocarcinoma differentiation. Using PSHG, we imaged normal and pathological stomach tissue samples which included well differentiated, moderately differentiated, and poorly differentiated gastric adenocarcinomas. Second harmonic generation (SHG) imaging is a non-linear optical microscopy technique that does not require staining of tissue samples due to the emission of SHG signals from intrinsic collagen fibers in the ECM. Therefore, it is less susceptible to observer variability compared to standard empirical staining techniques. For each sample image, PSHG analysis was performed to obtain , a structural parameter associated with the degree of collagen disorder. Results showed that the mean value was significantly greater in pathological tissue in patients compared to their adjacent normal tissue, which indicated a higher degree of structural disorder in cancerous tissue. There was a
significant increase in mean values from well differentiated to poorly differentiated
adenocarcinoma. There was no significant difference in mean values for groups that were closer to their degrees of tissue differentiation, such as between well differentiated and moderately differentiated, and between moderately differentiated and poorly differentiated adenocarcinomas. These findings suggest that there is greater disorder of collagen structure in the tumour microenvironment compared to adjacent normal tissue. Patients with poorly differentiated gastric adenocarcinoma are potentially ideal candidates for PSHG as a diagnostic technique
Cyclic alkyl phosphino carbenes – a synthetic investigation
Get PDF1 online resource (64 pages) : illustrations (some colour), graphsIncludes abstract.Includes bibliographical references (pages 63-64).A proposed synthetic pathway to produce a cyclic (alkyl)(phosphino) carbene (CAPC)has been investigated. 1-bromo-2,4,6-tritertbutylbenzene (-2,4,6-tritertbutylbenzene =mes*) was used to produce Mes*PCl2. A ring closure to form a phosphacycle was performed, a methyl group was added to the phosphorus and was reacted with N-bromosuccinimide to form the carbene precursor. The purpose for this synthesis is to attempt to replicate CAACs and improve their properties by replacing nitrogen with phosphorus. A less sterically bulky approach was done using only one ortho tBu to allow the use of more sterically bulky substituents at phosphorus. This synthesis provides a start to synthesizing the first CAPC