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The effects of Dissolved Organic Matter (DOM) sources on Pb2+, Zn2+ and Cd2+ binding

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Creator (cre): Chen, Weibin, Thesis advisor (ths): Gueguen, Celine, Thesis advisor (ths): Smith, Scott, Degree committee member (dgc): McGeer, James, Degree granting institution (dgg): Trent University
Abstract:

Metal binding to dissolved organic matter (DOM) determines metal speciation and strongly influences potential toxicity. The understanding of this process, however, is challenged by DOM source variation, which is not always considered by most existing metal speciation models. Source determines the molecular structure of DOM, including metal binding functional groups. This study has experimentally showed that the allochthonous-dominant DOM (i.e. more aromatic and humic) consistently has higher level of Pb binding than the autochthonous-dominant DOM (i.e. more aliphatic and proteinaceous) by more than two orders of magnitude. This source-discrimination, however, is less noticeable for Zn and Cd, although variation still exceeds a factor of four for both metals. The results indicate that metal binding is source-dependent, but the dependency is metal-specific. Accordingly, metal speciation models, such as the Windermere Humic Aqueous Model (WHAM), needs to consider DOM source variations. The WHAM input of active fraction of DOM participating in metal binding (f) is sensitive to DOM source. The commonly-used f = 0.65 substantially overestimated the Pb and Zn binding to autochthonous-dominant DOM, indicating f needs to be adjusted specifically. The optimal f value (fopt) linearly correlates with optical indexes, showing a potential to estimate fopt using simple absorbance and/or fluorescence measurements. Other DOM properties not optically-characterized may be also important to determine fopt, such as thiol, which shows strong affinity to most toxic metals and whose concentrations are appreciably high in natural waters (< 0.1 to 400 nmol L-1). Other analytical techniques rather than Cathodic Stripping Voltammetry (CSV) are required to accurately quantify thiol concentration for DOM with concentration > 1 mg L-1. To better explain the DOM-source effects, the conditional affinity spectrum (CAS) was calculated using a Fully Optimized ContinUous Spectrum (FOCUS) method. This method not only provides satisfactory goodness-of-fit, but also unique CAS solution. The allochthonous-dominant DOM consistently shows higher Pb affinity than autochthonous-dominant DOM. This source-discrimination is not clearly observed for Zn and Cd. Neither the variability of affinity nor capacity can be fully explained by the variability of individual DOM properties, indicating multiple properties may involve simultaneously. Together, the results help improve WHAM prediction of metal speciation, and consequently, benefit geochemical modelling of metal speciation, such as Biotic Ligand Model for predicting metal toxicity.

Author Keywords: Dissolved organic matter, Metal binding, Source, Windermere Humic Aqueous Model

2017

Nunavik Inuit Knowledge of Beluga: Using Multiple Methods, Tools, and Applications to Enhance our Understanding of Marine Mammal Ecology

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Creator (cre): Breton-Honeyman, Kaitlin Nell, Thesis advisor (ths): Furgal, Chris M, Degree committee member (dgc): Hammill, Michael O, Degree committee member (dgc): Hickie, Brendan, Degree granting institution (dgg): Trent University
Abstract:

Socio-ecological systems are inherently complex and marine mammals are fundamentally challenging to study. In the Arctic, marine mammals occupy a central ecological role, as nutrient cyclers and as a source of food and culture for Indigenous peoples. Inuit have developed a rich knowledge system, which has not been fully actualized in application in most Arctic research. Considering the need for the best available information in marine mammal ecology, the research question guiding this dissertation was: How can multiple methods and approaches be used to more effectively gather, understand, and represent Inuit Knowledge for an improved understanding of marine mammal ecology?

The dissertation investigates this question using a case study of beluga in Nunavik (Arctic Quebec) drawing on the expertise of hunters and Elders to better understand complex questions in marine mammal ecology. The thesis uses a transdisciplinary approach to address the dissertation objective and is comprised of a general introduction, followed by four chapters formatted as journal manuscripts, and closes with an integrated discussion and conclusion. The first manuscript examines the contributions of Traditional Ecological Knowledge (TEK) of beluga to marine mammal literature. The second manuscript uses a sub-set of data gathered through participant mapping to apply a mapping method to explore how the spatial aspects of TEK could be better documented, analyzed, and represented. The third and fourth papers are based on the knowledge shared by hunters and Elders. The third explores the questions 'why do beluga migrate?' and 'what factors influence beluga movement?'. The fourth investigates aspects of beluga foraging ecology.

This dissertation makes methodological contributions through the application of kernel density estimators to participant maps as a method for transforming multiple mapped narratives into a quantitative database. The understandings shared by hunters and Elders make significant ecological contributions, particularly to foraging (e.g. diet composition and seasonal energy intake), and movement ecology (e.g. potential drivers of migration). Broadly these findings contribute to our collective understanding of beluga ecology and have implications for wildlife management.

Author Keywords: Arctic, Beluga biology, foraging ecology, Inuit Knowledge, migration, transdisciplinary

2017

Native Art as seen through Native Eyes: An examination of contemporary Native art From a Storytelling Perspective

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Creator (cre): Phillips, Robert Alvin, Thesis advisor (ths): Dockstator, Mark, Degree committee member (dgc): Newhouse, David, Degree committee member (dgc): Lacombe, Michele, Degree granting institution (dgg): Trent University
Abstract:

Since the end of the Second World War, artists of Native descent have engaged with the Fine Art world where their work has come to be placed in the category of Native art. As a result of my journey, I have come to realize that in the Fine Art world the term Native art tends to be associated with the practices of our ancestors in times past obscuring our contemporary nature. In the present day context, however, I see an evolution and will tell the stories of the artists I met, who became a part of my life and thus a part of my narrative to point out that the voices of contemporary artists of Native descent, when speaking of their work, demonstrate a modern form of Native creativity, pride and joy that needs to be properly recognized. While Native artists do respect our traditions and do deal with issues of importance to our communities, they also create their artwork using sophisticated and modern techniques. It is up to us to make our contemporary nature known far and wide.

A storytelling approach based on the Michael Thrasher Medicine Wheel Teachings is employed to present the voices of our contemporary artists of Native descent who when speaking of their work create a rich and vibrant story of Native creativity, pride and joy.

Author Keywords: Culture, Elder, Indigenous Knowledge, Native Art, Storytelling

2015

Correlating density of states features with localization strength in disordered interacting systems

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Creator (cre): Perera, Jayanayana Lakmali, Thesis advisor (ths): Wortis, Rachel, Degree committee member (dgc): Atkinson, Bill, Degree granting institution (dgg): Trent University
Abstract:

Johri and Bhatt found singular behavior near the band edge in the density of states as well as in the inverse participation ratio of the Anderson model. These singularities mark a transition to an energy range dominated by resonant states. We study the interacting case using an ensemble of two-site Anderson-Hubbard systems. We find the ensemble-averaged density of states and generalized inverse participation ratio have more structure than in the non-interacting case because there are more transitions and in particular the transitions depend on the ground state. Nonetheless, there are regions of sharp decline in the generalized inverse participation ratio associated with specific density of state features. Moreover these features move closer to the Fermi level with the addition of interactions making them more experimentally accessible. Unfortunately resonances unique to interacting systems cannot be specifically identified.

Author Keywords: Correlated electrons, Disorder, Localization

2015

Canid Predation of Domestic Sheep (Ovis aries) on Ontario Farms: Land Cover Associations and Disruptive Deterrent Testing

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Creator (cre): Nixon, Katrina Leigh, Thesis advisor (ths): Pond, Bruce A, Thesis advisor (ths): Patterson, Brent R, Degree committee member (dgc): Schaefer, James, Degree granting institution (dgg): Trent University
Abstract:

Livestock predation by wild predators is a frequent and complicated issue, often cited as a significant factor in the decline of livestock production and justification for killing predators. Coyotes (Canis latrans) are the primary predators of sheep in Ontario. Some farms appear to be more susceptible to predation than others, despite the use of mitigation techniques. I explored land cover in the vicinity of farms as a potential influence on the level of predation, as coyote abundance and wild prey are correlated with certain habitat types. Using model competition, I show that landscape explains little variation in predation levels over all farms, but can explain 27% of variation in the percent of a flock killed. Total forest edge habitat and distance between forest patches were both positively associated with losses, suggesting a reduction in forest cover surrounding a farm puts the flock at greater risk. In addition, I tested four disruptive deterrents for effectiveness at protecting flocks. A matched-pairs analysis did not show a statistically significant benefit of these non-lethal mitigation tools.

Author Keywords: Alternative Prey, Canis latrans, Coyote, Landscape, Predation Deterrents, Sheep

2015

The Involvement of Endogenous Plant Hormones in The Regulatory Network of Fatty Acid Biosynthesis in Soybean Seed

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Creator (cre): Nguyen, Thien Quoc, Thesis advisor (ths): Emery, Neil, Thesis advisor (ths): Narine, Suresh, Degree granting institution (dgg): Trent University
Abstract:

The activities of phytohormones during the reproductive phase have been partially clarified in seed physiology while the biological role of plant hormones in oil accumulation during seed development has been investigated in part only. In this research, fatty acid (FA) contents and hormone profiles, including abscisic acid (ABA) and cytokinins (CKs) of seed samples in four different stages and comparing six soybean varieties have been investigated in order to examine the hypothesis that the endogenous plant hormones play important roles in FA production in soybean seeds. The FA contents increased significantly during this period while the hormone concentrations gradually declined towards the seed physical maturation. However, the interactions between FA contents and hormone profiles were complex and went beyond linear correlations. Hormone metabolism in the earlier stages of seed maturation period demonstrated numerous robust relationships with FA accumulations, as derived from several simple and multiple regression models in the determination of different FA contents. Evaluation of the effects of exogenous ABA and trans-Zeatin (tZ) on FA biosynthesis has revealed that ABA appears to be involved in the accumulations of unsaturated FAs while tZ participated in the synthesis of saturated and unsaturated FAs. Notably, the alterations of FA synthesis differ according to what exogenous hormone concentrations could be used.

Author Keywords: Abscisic acid, Cytokinin, Fatty acid, Seed development, Soybean

2016

Assessment of Corporate Social Responsibility Compliance: A Study of Two Canadian Oil and Gas Corporations

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Creator (cre): Kolawole, Olujoba Alaji, Thesis advisor (ths): Zohar, Asaf, Degree committee member (dgc): Bishop, John, Degree granting institution (dgg): Trent University
Abstract:

The modern world faces a number of social, economic, and environmental sustainability challenges. Since businesses are assumed to have a role in causing such problems, they must also play a role in finding solutions.

In Canada, the extent to which corporate social responsibility is institutionalized in the oil and gas industry remains a contentious issue among stakeholders. This study examines the extent of corporate social responsibility compliance in oil and gas corporations through an assessment of the corporate social responsibility reporting of two oil and gas organizations. Comparative analysis was used to determine each firm's operational level compliance with Global Reporting Initiative (GRI) guidelines in terms of corporate social responsibility reporting. The study showed that firms' levels of compliance with social, economic, and environmental responsibility are unequal. As a result, a five-part mechanism is recommended to strengthen corporate social responsibility in the industry.

Author Keywords: Corporate social responsibility, Corporate social responsibility compliance, Corporate social responsibility reporting, Sustainable development

2016

It's a Mad, Mad, Mad, Mad World: a Critical Analysis Of The Perceptions And Lived Experiences of Mental Health and Illness In Kuwait

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Creator (cre): Khullar, Neha, Thesis advisor (ths): Coughlan, Rory, Degree committee member (dgc): Navara, Geoff, Degree committee member (dgc): Summerfeldt, Laura, Degree granting institution (dgg): Trent University
Abstract:

The purpose of this study was to understand the lived experiences of mental health and illness in Kuwait. Twenty-six participants were interviewed, including mental health professionals, family physicians, and service users. Findings suggest that inequality, oppression, and human rights violations may drive mental health issues in Kuwait. However, rather than addressing these factors, many healthcare providers are endorsing psychological testing and psychiatric medication, which may be resulting in the same iatrogenic (physician-induced) drug dependence that is seen in North America. An analysis of mainstream psychological theory, research and practice is provided, along with a bioethical critique of the World Health Organization's efforts to reduce the global 'burden' of mental disorders. This study cuts across disciplinary boundaries and 1) supports medical anthropologists' criticisms of the 'advancement' of global mental healthcare; 2) provides participant-driven, community-based alternatives that are specific to Kuwait; and 3) informs culturally defined notions of 'care' and 'ethics'.

Author Keywords: Clinicians' narratives, Critical Psychology, Human rights, Kuwait, Qualitative research, Transcultural psychiatry

2017

From Negation to Affirmation: Witnessing the Empty Tomb in the Era of Forensic Scientific Testimony

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Creator (cre): Cyr, Rachel Esther, Thesis advisor (ths): Junyk, Ihor, Thesis advisor (ths): Bordo, Jonathan, Degree committee member (dgc): Pletenac, Tomislav, Degree committee member (dgc): Milloy, John, Degree committee member (dgc): Innis, Randy, Degree granting institution (dgg): Trent University
Abstract:

Forensic scientific practice is conventionally understood as a solution to absence. With every technological advance the power and span of the archive grows and with it revives hopes of uncovering facts and locate bodies that might put genocide denial and/or negationism to rest. Destruction, however, continues to define the reality and conditions

for testimony in the aftermath of mass atrocity. This means that even as forensic scientific practice grows in its capacity to presence that which was previously unpresentable, destruction and the concomitant destruction of archive require that we consider what it means to remember with and without the archive alike. This dissertation explores the impact of forensic science on cultural memory through a choice of two case studies (set in Kosovo and Srebrenica respectively) where forensic scientific methods

were involved in the investigation of atrocities that were openly denied.

This dissertation makes an agnostic argument that the biblical example of the empty tomb can serve as a paradigm to understand the terms of witnessing and testifying to absence in the era of forensic scientific investigations. Specifically, it posits the following theses with regards to the empty tomb: it is a structure and an event that emerges at the intersection of forensic science's dual property as an indexical technique and as a witness

function, it cannot be validated through historiographic or forensic scientific methods (it is un-decidable) and as such serves as a corrective the fantasy of the total archive, is represented in the contemporary genre of forensic landscape; and because it breaks with the forensic imperative, it compels alternative uses for testimony and memorial practices that need not be defined by melancholia as it can accommodate forms of testimony that

are joyous and life affirming.

Author Keywords: Absence, Archive, Forensic, Memory, Testimony, Witness

2017

Executive Function as a Predictor of Emotional, Behavioural, and Social Competence Problems in Children with Epilepsy

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Creator (cre): Healy, Sarah, Thesis advisor (ths): Im-Bolter, Nancie, Degree committee member (dgc): Olds, Janet, Degree granting institution (dgg): Trent University
Abstract:

The study aimed to examine the association between different components of executive function (EF) and emotional, behavioural, and social competence problems (EBSP) in children with epilepsy. Although there is evidence of an association between EBSP and EF in typically developing children, little research has examined this relation in children with epilepsy. The sample comprised of 42 children with epilepsy, aged 6.0 to 18.1 years old. Results showed that EBSP were associated with EF in these children; however, different components of EF were related to different EBSP. Shifting was a significant predictor of emotional, behavioural, and social competence problems in children with epilepsy, whereas inhibition was a significant predictor of behavioural problems. This suggests that children with epilepsy, with different EF profiles may be at-risk for developing different types of problems. These results may aid researchers and clinicians with the development of new techniques to identify and treat children with EBSP.

Author Keywords: behavioural problems, emotional problems, epilepsy, executive function, social competence

2017