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Equilibria and distribution models of ionizing organic chemical contaminants in environmental systems
Ionizing organic chemicals are recognized as constituting a large fraction of the organic chemicals of commerce. Many governments internationally are engaged in the time-consuming and expensive task of chemical risk assessment for the protection of human and environmental health. There are standard models that are consistently used to supplement experimental and monitoring data in such assessments of non-ionizing organics by both government regulators and industry stakeholders. No such standard models exist for ionizing organics. Equilibrium distribution models, the foundational equations within multimedia environmental fate models for non-ionizing organics, were developed for the standard series of biphasic systems: air-water, particle-water, air-particle and organic-aqueous phases within living tissue. Multiple chemical species due to the ionization reaction were considered for each system. It was confirmed that, under select conditions, the properties of the neutral parent are sufficient to predict the overall distribution of the organic chemical. Complications due to biotransformation and paucity of identifiable equilibrium distribution data for ionizing organics limited the development of the model for living tissues. However, the equilibrium distributions of ionizing organics within this biotic system were shown to correlate with the abiotic sediment-water system. This suggests that the model developed for particle-water systems should be adaptable to the biotic system as model input and test data become available. Observational data for soil- and sediment- water systems, i.e., particle-water systems, allowed the development of a primarily non-empirical distribution equation for mono-protic acids; this model was almost entirely theoretically derived. The theoretical approach to model development allowed a quantitative assessment of the role of the neutral ion pair, resulting from the complexation of the organic anion with metal cations. To demonstrate the model's potential usefulness in governmental screening risk assessments, it was applied to a broad range of mono-protic organics including drugs and pesticides using standard property estimation software and generic inputs. The order-of-magnitude agreement between prediction and observation typical of the existing models of non-ionizing organics was generally achieved for the chemicals tested. The model was sensitive to the octanol-water partition coefficient of the most populous species. No calibration set was used in the development of any of the models presented.
Author Keywords: bioconcentration, chemical equilibrium, environmental modelling, ionizing organic, sorption
Identifying non-local individuals at the ancient Maya centre of Minanha, Belize through the use of strontium isotope analysis
Strontium isotope analysis has become an important tool in identifying non-local individuals at archaeological sites. For this study, tooth enamel samples were collected from 20 individuals from the ancient Maya centre of Minanha, Belize. These individuals date to periods spanning the formative occupation of the centre, as well as its fluorescence and protracted decline. The goal of this research was to investigate if non-local individuals played a role in Minanha's formation and fluorescence. The study utilised published strontium isotope maps from Belize and the Yucatán in order to establish local 87Sr/86Sr values. The values of the Minanha enamel samples (n = 20) fell predominantly outside of the expected strontium isotope range; this result seemed implausible and an alternative method was utilised to establish the local 87Sr/86Sr values. The outlier method identified 5/20 (25%) non-local individuals. All of the non-local individuals had 87Sr/86Sr values that coincided with published 87Sr/86Sr values reported from within 10 - 20 km of Minanha. However, some strontium isotope values also corresponded with 87Sr/86Sr values reported from regions >50 km away. The percentage of non-locals at Minanha is consistent with other Mesoamerican centres. This study emphasises the importance of collecting local baseline 87Sr/86Sr values from sites themselves, as 87Sr/86Sr values from neighbouring regions might not reflect local strontium isotope values.
Author Keywords: Ancient Maya, bioarchaeology, migration, mobility, Vaca Plateau
Fractionation of Mercury Isotopes in an Aqueous Environment: Chemical Oxidation
The study of fractionation patterns for the stable isotopes of mercury is a growing field. The potential for stable isotopes to trace mercury through the environment from pollution sources to sinks make the subject interesting to geochemists and useful to a wider audience. The purpose of this study is to measure the fractionation of mercury as it is oxidized in an aqueous medium. Samples in this study are prepared by chemically oxidizing different proportions of elemental mercury using four different oxidants. The oxidized portion is then separated from the elemental portion and an analysis of the isotope ratios for both portions is performed using a multicollector inductively coupled plasma mass spectrometer MC-ICP/MS. These isotope ratios are measured against the preoxidation isotope ratio to determine what if any change has occurred. From the findings of this work, it is now known chemical oxidation causes both mass dependent and mass independent fractionation. Mass dependent fractionation causes an enrichment of the heavier isotopes in the oxidized portion while the opposite is true for the elemental portion. Mass independent fractionation occurred only in the odd isotopes and causes a depletion of odd isotopes in the oxidized portion and enrichment in the elemental portion. These trends were found to be true for all oxidants tested as the pattern of fractionation does not change with varying oxidants.
Author Keywords: Isotope, Mass Dependent, Mass Independent, Mercury, Oxidation
maskihkîyâtayôhkêwina; mashkikiiwaadizookewin: Cree and Anishnaabe Narrative Medicine in the Renewal of Ancestral Literature
maskihkîyâtayôhkêwina-
mashkikiiwaadizookewin:
Cree and Anishnaabe Narrative Medicine
in the Renewal
of Ancestral Literature
Jud Sojourn
This work represents an experiment in developing Cree and Anishnaabe nation-specific approaches to understanding Cree and Anishnaabe texts. The binding premise that guides this work has to do with narrative medicine, the concept that narrative arts, whether ancestral storytelling or current poetry have medicine, or the ability to heal and empower individuals and communities. As âtayôhkêwin in Cree and aadizookewin in Anishnaabemowin refer to ancestral traditional narratives, and while maskihkiy in Cree, and mashkiki in Anishnaabemowin refer to medicine, maskihkîyâtayôhkêwina and
mashkikiiwaadizookewin mean simply `narrative medicine' in Cree and Anishnaabemowin respectively.
After establishing a formative sense for what narrative medicine is, this work continues by looking at the bilingual Ojibwa Texts (1917, 1919) transcribed by William Jones in 1903-1905 on the north shore of Lake Superior and in northern Minnesota Anishnaabe communities, those spoken by Anishnaabe community members Gaagigebinesiikwe, Gaagigebinesii, Midaasookanzh, Maajiigaaboo, and Waasaagooneshkang. Then focus then turns to the bilingual Plains Cree Texts (1934) transcribed by Leonard Bloomfield at the Sweet Grass Reserve in Saskatchewan and spoken by Cree community members nâhnamiskwêkâpaw, sâkêwêw, cicikwayaw, kâ-kîsikaw pîhtokêw , nakwêsis, mimikwâs, and kâ-wîhkaskosahk. The themes that emerge from looking at these texts when combined with an appreciation for the poetics of the Cree and Anishnaabe languages provide the foundation for looking at newer poetry including the work of Cree poet Skydancer Louise Bernice Halfe, centering on the contemporary epic prayer-poem The Crooked Good (2007) and the works of Anishnaabe poet Marie Annharte Baker, focusing on Exercises in Lip Pointing (2003). Each poet emerged as having an understanding her own role in her respective nation as renewing the narrative practices of previous generations.
Understandings of the shape or signature of each of the four works' unique kind of narrative medicine come from looking at themes that run throughout. In each of the four works the maskihkîyâtayôhkêwina - mashkikiiwaadizookewin, the narrative medicine they express occurs through or results in mamaandaawiziwin in Anishnaabemowin or mamâhtâwisiwin, in Cree - the embodied experience of expansive relationality.
Keywords: Cree, Anishnaabe, nêhiyawêwin, Anishnaabemowin, narrative medicine, traditional stories, poetics, poetry, literary criticism, literary nationalism, Indigenous, indigenist.
Author Keywords: Anishnaabe, Anishnaabemowin, Cree, Indigenous, nêhiyawêwin, Poetics
Time Series Algorithms in Machine Learning - A Graph Approach to Multivariate Forecasting
Forecasting future values of time series has long been a field with many and varied applications, from climate and weather forecasting to stock prediction and economic planning to the control of industrial processes. Many of these problems involve not only a single time series but many simultaneous series which may influence each other. This thesis provides methods based on machine learning of handling such problems.
We first consider single time series with both single and multiple features. We review the algorithms and unique challenges involved in applying machine learning to time series. Many machine learning algorithms when used for regression are designed to produce a single output value for each timestamp of interest with no measure of confidence; however, evaluating the uncertainty of the predictions is an important component for practical forecasting. We therefore discuss methods of constructing uncertainty estimates in the form of prediction intervals for each prediction. Stability over long time horizons is also a concern for these algorithms as recursion is a common method used to generate predictions over long time intervals. To address this, we present methods of maintaining stability in the forecast even over large time horizons. These methods are applied to an electricity forecasting problem where we demonstrate the effectiveness for support vector machines, neural networks and gradient boosted trees.
We next consider spatiotemporal problems, which consist of multiple interlinked time series, each of which may contain multiple features. We represent these problems using graphs, allowing us to learn relationships using graph neural networks. Existing methods of doing this generally make use of separate time and spatial (graph) layers, or simply replace operations in temporal layers with graph operations. We show that these approaches have difficulty learning relationships that contain time lags of several time steps. To address this, we propose a new layer inspired by the long-short term memory (LSTM) recurrent neural network which adds a distinct memory state dedicated to learning graph relationships while keeping the original memory state. This allows the model to consider temporally distant events at other nodes without affecting its ability to model long-term relationships at a single node. We show that this model is capable of learning the long-term patterns that existing models struggle with. We then apply this model to a number of real-world bike-share and traffic datasets where we observe improved performance when compared to other models with similar numbers of parameters.
Author Keywords: forecasting, graph neural network, LSTM, machine learning, neural network, time series
Population Genetics and Gut Microbiome Composition Reveal Subdivisions and Space Use in a Generalist and Specialist Ungulate
Natural populations are often difficult and costly to study, due to the plethora of confounding processes and variables present. This is of particular importance when dealing with managed species. Ungulates, for example, act as both consumers and prey sources; they also provide economic benefit through harvest, and as such, are of high ecological and economic value. I addressed conservation and management concerns by quantifying subdivision in wild populations and combined movement with non-invasive sampling to provide novel insight on the physiological drivers of space use in multiple species. This thesis explored biological patterns in ungulates using two distinct approaches: the first used molecular genetics to quantify gene flow, while the second examined the relationship between movement and the gut microbiome using high-throughput sequencing and GPS tracking. The goal of the first chapter was to quantify gene flow and assess the population structure of mountain goats (Oreamnos americanus) in northern British Columbia (BC) to inform management. I used microsatellites to generate genotype data and used a landscape genetics framework to evaluate the possible drivers behind genetic differentiation. The same analyses were performed at both a broad and fine scale, assessing genetic differentiation between populations in all of northern BC and in a case management study area northeast of Smithers BC. The results indicated panmixia among mountain goats regardless of scale, suggesting distance and landscape resistance were minimally inhibiting gene flow. Therefore, management at local scales can continue with little need for genetically informed boundaries, but regulations should be tailored to specific regions incorporating data on local access and harvest pressure. My second chapter aimed to determine the extent to which the gut microbiome drives space-use patterns in a specialist (mountain goat) and generalist (white-tailed deer, Odocoileus virginianus) ungulate. Using fecal samples, we generated genomic data using 16S rRNA high-throughput sequencing to evaluate gut diversity and gut microbiome characteristics. Additionally, individuals were fitted with GPS collars so that we could gain insight into movement patterns. Gut microbiome metrics were stronger predictors of space use and movement patterns with respect to home range size, whereas they were weaker predictors of habitat use. Notably, factors of both the gut microbiome and age of a given species were correlated with changes in space use and habitat use. Ultimately, this research linked high-throughput sequencing and GPS data to better understand ecological processes in wild ungulates.
Author Keywords: gene flow, genomics, gut microbiome, home range, population genetic structure, ungulates
Shoreline Stewardship: Capacity Building through ENGO Programming and Local Partnerships
This thesis aimed to determine what factors influence individual- and community-level shoreline stewardship attitudes and behaviours. Shoreline stewardship is part of the broader literature of environmental stewardship and place-based conservation. The needs and barriers limiting stewardship action were examined, as were the opportunities for increased impact. The Love Your Lake (LYL) program served as a case study into the impact of ENGO programming on shoreline stewardship among shoreline property owners in Ontario. This was investigated using a program workshop, interviews and focus groups with past program participants, and existing participant survey data. Community-Based Social Marketing principles were used to further examine the opportunities for increased impact on stewardship behaviour. The study found that the LYL program was effective in starting or continuing a conversation in communities around shoreline health. Some of the remaining needs and/or barriers included limited time at the cottage; limited knowledge of how to fix existing shoreline issues; low stock of local native plants and environmentally minded landscapers; ineffective messaging; a lack of interest, enthusiasm or concern; and weak environmental policies and governance of shorelines. Some participants also listed cost as a barrier, while others felt it had been well addressed already. Most participants thought that education could be a barrier but that it had been well addressed locally through LYL or other programming. Some key motivators and opportunities to increase shoreline stewardship included community building, increased lake association capacity, improved communication and marketing strategies, and persistence.
Author Keywords: Community-Based Social Marketing, Environmental Stewardship, Lake Health, Place-Based Conservation, Pro-Environmental Behaviour, Shoreline Stewardship
Comparative efficacy of eDNA and conventional methods for monitoring wetland anuran communities
Identifying population declines and mitigating biodiversity loss require reliable monitoring techniques, but complex life histories and cryptic characteristics of anuran species render conventional monitoring challenging and ineffective. Environmental DNA (eDNA) detection is a highly sensitive and minimally invasive alternative to conventional anuran monitoring. In this study, I conducted a field experiment in 30 natural wetlands to compare efficacy of eDNA detection via qPCR to three conventional methods (visual encounter, breeding call, and larval dipnet surveys) for nine anuran species. eDNA and visual encounter surveys detected the greatest species richness, with eDNA methods requiring the fewest sampling events. However, community composition results differed among methods, indicating that even top performing methods missed species detections. Overall, the most effective detection method varied by species, with some species requiring two to three methods to make all possible detections. Further, eDNA detection rates varied by sampling season for two species (A. americanus and H. versicolor), suggesting that species-specific ecology such as breeding and larval periods play an important role in eDNA presence. These findings suggest that optimized monitoring of complex anuran communities may require two or more monitoring methods selected based on the physiology and biology of all target species.
Author Keywords: amphibian, anuran, conventional monitoring, eDNA, environmental DNA, species richness
Archaeology and Reconciliation in the Williams Treaties Territory
This thesis examines the history of Indigenous inclusion in the discipline of archaeology and how archaeologists can provide reconciliation when working with Indigenous peoples in their territory. This thesis focuses on the territory of the Williams Treaties with a particular focus on the location of Nogojiwanong (Peterborough). My data consists of in-depth interviews from ten informants and studying three case studies that happened in the area. I take my informants' suggestions and apply them to my case studies, to show practical examples of how we can provide reconciliation in the field of archaeology.
Author Keywords: Decolonization , Heritage Management , Indigenous, Reconciliation
Electrochemical Biosensors for Neurodegenerative Disease Biomarkers: Investigations into the origin and diagnosis of Alzheimer's disease and amyotrophic lateral sclerosis
The onset of neurodegenerative diseases such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS) are typically characterised by the aggregation of protein biomarkers into cytotoxic fibrils. Novel means of analysing these biomarkers are needed to expand the literature toward earlier diagnosis of these conditions. Electrochemical sensors could offer the sensitivity and selectivity needed for specialised analysis, including potential point-of-care applications. The AD biomarker Tau, and ALS biomarker TDP-43 proteins are explored here by using a label-free electrochemical sensors. Tau protein was covalently bound to gold electrode surface to study the in vitro mechanisms of aggregation for this protein. An immunosensor to TDP-43 was developed by covalently binding primary TDP-43 antibodies (Abs) on gold electrode surface. A novel direct ELISA sensor for TDP-43 with visual detection and electrochemical quantification was also developed. The results validated the experimental designs toward specialised and selective analysis of these biomarkers and their aggregation mechanisms.
Author Keywords: ALS, Alzheimer's, Biosensors, Electrochemistry, Tau, TDP-43