Digital Commons Network^™

Coordination Chemistry Using Strategic Design Of Ligands For Switchable Properties, Delara Joekar

Theses and Dissertations (Comprehensive)

Coordination-driven self-assemblies are multifunctional molecular systems that provide an efficient method for miniaturization towards functional devices with diverse applications. Herein, the synthesis of novel pyrazole-based ligands suitable for construction of coordination assemblies is reported. These were designed using a strategy that incorporates the presence of both cationic and anionic coordination sites, and a third site for further functionalization. This design strategy has been used because there is still a knowledge gap for controlling the directionality of weak molecular forces in the presence of stronger competing forces. The structural characterization of these ligands, their Hirshfeld surface analysis, and select coordination complexes …

The Wilderness Which Never Was: A History Of The Białowieża Forest 1850–1947, Rafal Stolarz

Theses and Dissertations (Comprehensive)

Located on both sides of the Polish-Belarusian border in north-eastern Poland, the Białowieża forest is the largest remaining remnant of the vast primeval forest that once covered most of Europe. It is also home to Europe’s biggest land animal—the European bison. Over the past century Polish governments, as well as modern-day Polish and European environmental groups, have promoted the forest as the “last European wilderness.” Even today, the public regularly protests and decries news of human encroachment on the forest. Yet in reality, the Białowieża forest has been exploited and studied by humans for centuries, making it one of the …

"The Most Important Thing In Ipv Right Now": The Intersection Of Intimate Partner Violence And Brain Injury, Halina (Lin) Haag

Theses and Dissertations (Comprehensive)

The intersection of intimate partner violence (IPV) and brain injury (BI) has been almost entirely overlooked in research, practice, and policy, despite the known risks associated with the two conditions. Individually, IPV and BI are associated with elevated rates of unemployment, poverty, and homelessness, as well as increased mental health challenges. These social determinants of health, employment status, and income impact women’s wellbeing through access to safe accommodations, food security, and (dis)ability supports. These determinants are also related to an increased likelihood of experiencing addictions, mental health challenges, and physical danger, potentially leaving women vulnerable to ongoing violence. This qualitative …

The Influence Of Visual Perspective On The Cognitive Effort Required For Mental Representation, Jeffrey P. Hong

Theses and Dissertations (Comprehensive)

Mental representation is the process by which an individual simulates an event in their mind’s eye. This process is the foundation of the ability to remember the past, engage in prospective thinking, or imagine fictitious scenarios. An individual can mentally represent any event through their own eyes—the first-person perspective or from the viewpoint of an external observer—the third-person perspective. The perspective of representation influences outcomes related to memory, visuospatial processing, affect, social cognition, clinical diagnoses, and language processing. In turn, an individual’s tendency to favour either perspective is shaped by related factors.

The current research consists of four experiments, designed …

Erwinia Amylovora Phage Therapy: Biocontrol Formulation, Receptor Identification, Resistance Mechanisms, Nassereldin Ibrahim

Theses and Dissertations (Comprehensive)

Fire blight is known as a disease of Rosaceae and it displays infection symptoms in about 200 species in 40 rosaceous genera. The most economically important crops that are affected by fire blight are apples and pears. Fire blight can cause severe outbreaks and a single fire blight outbreak can disrupt orchard production for years. The bacterium that causes this disease is indigenous in North America, and according to Statistics Canada, economic losses in apples and pears were valued at an estimated $4 million in 2005, which is approximately 5% of the total production. In addition, production costs can increase …

Dual Suppression Of Glossina Pallidipes Using Entomopathogenic Fungal-Based Biopesticides And Sterile Insect Technique, Fidelis L.O. Ombura, Adly M.M. Abd-Alla, Komivi S. Akutse, Steven Runo, Paul O. Mireji, Rosemary Bateta, Joseck E. Otiwi, Inusa J. Ajene, Fathiya M. Khamis

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Tsetse flies and trypanosomosis significantly impact bovine production and human health in sub-Saharan Africa, exacerbating underdevelopment, malnutrition, and poverty. Despite various control strategies, long-term success has been limited. This study evaluates the combined use of entomopathogenic fungi (EPF) and the sterile insect technique (SIT) to combat tsetse flies. Eleven EPF isolates were tested against teneral males of Glossina pallidipes, focusing on mortality rates, radial growth, and impacts on fly fitness. Temperature effects on conidial growth, sporulation, and spore yield of SIT-compatible/tolerant strains were also assessed. The fungal isolates significantly influenced mortality rates in both unirradiated and irradiated (SIT-treated) males (p <  0.0001). Metarhizium anisopliae strains ICIPE 20, ICIPE 32, ICIPE 41, ICIPE 62, ICIPE 78, and Beauveria bassiana ICIPE 603 showed higher SIT compatibility/tolerance with LT50 values of 11–30 days, compared to other more virulent isolates with LT50 values of 4–9 days. Temperature significantly affected the radial growth of SIT-compatible EPF strains (p <  0.0001), with M. anisopliae ICIPE 78 exhibiting the fastest conidia growth at 25°C. Spore yield varied significantly across temperatures (15–40°C), and the thermal range for conidia germination of SIT-compatible strains was 8.1–45.4°C, with an optimal range of 26.7–31.1°C. Moreover, infected unirradiated females and irradiated males (donors) successfully transmitted conidia to untreated flies (receivers) without significant differences in survival rates (p = 0.6438) and no observed sex dimorphism. Our findings highlight the potential of combining EPF and SIT as a novel dual approach that could effectively and synergistically suppress tsetse fly populations.

Insect Frass Fertilizer As A Regenerative Input For Improved Biological Nitrogen Fixation And Sustainable Bush Bean Production, Agnes Chepkorir, Dennis Beesigamukama, Harun I. Gitari, Shaphan Y. Chia, Sevgan Subramanian, Sunday Ekesi, Birachi Eliud Abucheli, Jean Claude Rubyogo, Theodore Zahariadis, Gina Athanasiou, Aikaterini Zachariadi, Vasileios Zachariadis, Abdou Tenkouano, Chrysantus M. Tanga

All Peer-Reviewed Publications

Bush bean (Phaseolus vulgaris L.) production is undermined by soil degradation and low biological nitrogen fixation (BNF) capacity. This study evaluated the effect of black soldier fly frass fertilizer (BSFFF) on bush bean growth, yield, nutrient uptake, BNF, and profitability, in comparison with commercial organic fertilizer (Phymyx, Phytomedia International Ltd., Kiambu, Kenya), synthetic fertilizer (NPK), and rhizobia inoculant (Biofix, MEA Fertilizers, Nairobi, Kenya). The organic fertilizers were applied at rates of 0, 15, 30, and 45 kg N ha−1 while the NPK was applied at 40 kg N ha−1, 46 kg P ha−1, and 60 kg K ha−1. The fertilizers …

Comparative Microbiome Diversity In Root-Nodules Of Three Desmodium Species Used In Push-Pull Cropping System, Isack H. Adan, George Ochieng Asudi, Saliou Niassy, Abdul A. Jalloh, Johnstone Mutiso Mutua, Frank Chidawanyika, Fathiya Khamis, Zeyaur Khan, Sevgan Subramanian, Thomas Dubois, Daniel Munyao Mutyambai

All Peer-Reviewed Publications

Background: Desmodium species used as intercrops in push-pull cropping systems are known to repel insect-pests, suppress Striga species weeds, and shift soil microbiome. However, the mechanisms through which Desmodium species impact the soil microbiome, either through its root exudates, changes in soil nutrition, or shading microbes from its nodules into the rhizosphere, are less understood. Here, we investigated the diversity of root-nodule microbial communities of three Desmodium species- Desmodium uncinatum (SLD), Desmodium intortum (GLD), and Desmodium incanum (AID) which are currently used in smallholder maize push-pull technology (PPT). Methods: Desmodium species root-nodule samples were collected from selected smallholder farms in …

Plant-Parasitic Nematodes Associated With Maize, And Their Relationship With Soil Properties In Southern And Southwestern Ethiopia, Abebe W. Aseffa, Beira H. Meressa, Tadele Tefera, Kristina K. Green, Peter Anderson, Esayas Mendesil

All Peer-Reviewed Publications

Maize is an important cereal crop in sub-Saharan Africa (SSA). Plant-parasitic nematodes significantly impact maize production. However, research on maize nematodes in SSA is limited. The current study aimed to assess the occurrences and densities of nematodes associated with maize and to assess the correlation of some soil physicochemical properties with nematodes in southern and southwestern Ethiopia. One hundred and eighty-six soil and root samples were collected from 62 maize fields (31 from Hawassa Zuria and 31 from Mana districts). Eleven plant-parasitic nematode genera were identified. The most important genera of plant-parasitic nematodes identified were Meloidogyne and Pratylenchus, followed by …

Characterisation Of ‘Giant’ Cysts Of The Potato Cyst Nematode, Globodera Rostochiensis, Present In Potato Fields In Kenya, James A. Price, Kelsey Hunt, Newton Nyagah, Calvince Orage, Onesmus Mwaura, Solveig Haukeland, Danny Coyne, John T. Jones

All Peer-Reviewed Publications

Potato production in East Africa is seriously impacted by the potato cyst nematode (PCN), Globodera rostochiensis, where it has been recorded in at least three countries. In Kenya, it is widespread in all major potato-growing regions, often at very high densities. Consecutive cropping of potato on the same land and a sub-tropical climate have influenced PCN biology. For example, unusually large cysts have been regularly recovered. We have analysed the biological properties of these ‘giant cysts’. The giant cysts contained more eggs than those recovered from UK fields. Egg size did not differ from UK populations and there was no …

Tissue-Specific Localization Of Tick-Borne Pathogens In Ticks Collected From Camels In Kenya: Insights Into Vector Competence, Rua Khogali, Armanda Bastos, Joel L. Bargul, Dennis Getange, James Kabii, Daniel Masiga, Jandouwe Villinger

All Peer-Reviewed Publications

Background: Tick-borne pathogen (TBP) surveillance studies often use whole-tick homogenates when inferring tick-pathogen associations. However, localized TBP infections within tick tissues (saliva, hemolymph, salivary glands, and midgut) can inform pathogen transmission mechanisms and are key to disentangling pathogen detection from vector competence. Methods: We screened 278 camel blood samples and 504 tick tissue samples derived from 126 camel ticks sampled in two Kenyan counties (Laikipia and Marsabit) for Anaplasma, Ehrlichia, Coxiella, Rickettsia, Theileria, and Babesia by PCR-HRM analysis. Results: Candidatus Anaplasma camelii infections were common in camels (91%), but absent in all samples from Rhipicephalus pulchellus, Amblyomma gemma, Hyalomma dromedarii, …

Bacteria Associated With Parthenium Hysterophorus Root Exudate Influence Olfactory Oviposition Responses Of Anopheles Gambiae, Trizah K. Milugo, Baldwyn Torto, David P. Tchouassi

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Introduction: Previously, we documented that the malaria vector Anopheles gambiae responds to volatile emissions from the root exudate water of the invasive plant, Parthenium hysterophorus. However, the origin of the volatiles remains to be investigated. Here, we isolated bacteria from the root exudate water of the plant, test the influence of their volatiles in gravid An. gambiae oviposition, and examined relationships between volatile profiles and oviposition. Methods: Bacteria from root exudate water of P. hysterophorus were isolated using culture on Luria Bertani medium and identified by sequencing the 16S rRNA gene. Cultures of individual isolates were evaluated for egg laying …

Chitin-Enriched Insect Frass Fertilizer As A Biorational Alternative For Root-Knot Nematode (Meloidogyne Incognita) Management, James Kisaakye, Dennis Beesigamukama, Solveig Haukeland, Sevgan Subramanian, Paul K. Thiongo, Segenet Kelemu, Chrysantus M. Tanga

All Peer-Reviewed Publications

Root-knot nematodes (Meloidogyne spp.) are serious pests of most food crops, causing up to 100% yield loss. Nevertheless, commercial nematicides are costly and harmful to the environment. While the nematicidal potential of crustacean and synthetic chitin has been demonstrated globally, research on the potential of insect-derived chitin for nematode control has received limited attention. Here, seven chitin-fortified black soldier fly frass fertilizer extracts (chFE) were assessed for their suppressiveness of Meloidogyne incognita and impacts on spinach growth in comparison with a commercial nematicide using in vitro and in vivo bioassays. The performance of chFE and control treatments was assessed by …

Integrating Vegetables In Push-Pull Technology: Gendered Preferences Of Smallholder Farmers In Western Kenya, F. O. Ouya, J. O. Pittchar, F. Chidawanyika, Z. R. Khan

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Transformative rural smallholder agriculture addressing biophysical constraints requires farmer-led innovations for increased technology adoption. Following the need to further intensify the cereal push-pull technology (PPT) for pest and weed control through integration with vegetables, we conducted surveys to determine suitable vegetables across three different counties in Kenya namely Homabay, Siaya, and Trans-Nzoia. Farming in these areas is predominantly maize based and introducing vegetables to the system will improve household food and nutritional security, together with income. A systematic random sampling method was used to sample a total of 124 smallholder farmers who were interviewed during field days where farmer awareness …

Self-Exciting Point Processes In Real Estate, Ian Fraser

Theses and Dissertations (Comprehensive)

This thesis introduces a novel approach to analyzing residential property sales through the lens of stochastic processes by employing point processes. Herein, property sales are treated as point patterns, using self-exciting point process models and a variety of statistical tools to uncover underlying patterns in the data. Key findings include the identification and explanation of clustering in both space and time, and the efficacy of a temporal Hawkes process with a sinusoidal background in predicting home sale occurrences. The temporal analysis starts by employing the state of art techniques for time series data like regression, autoregressive, and autoregressive integrated moving …

The Prevalence And Consequences Of Gender-Based Violence Among Trans And Non-Binary University Students In Ontario, Jia Qing Wilson-Yang

Theses and Dissertations (Comprehensive)

Community studies documenting gender-based violence (GBV) experienced by trans and non-binary (TNB) people often find differences in prevalence across TNB subgroups. Studies of TNB university students tend to treat them as a homogenous group, thus gender differences in terms of subgroups are unknown. Using data collected from TNB Ontario university students, I examined the prevalence and impacts of GBV across three TNB subgroups (trans man spectrum, trans women spectrum, and gender queer/non-binary). Specifically, reflecting subtle and overt forms of GBV, among each subgroup I explored the frequency of trans environmental microaggressions, trans interpersonal microaggressions, and victimization, and their relationship with …

Dancing Around And Through Harm: Examining The Lived Experiences Of Women Of Colour With Gender-Based Violence In The Toronto & Kitchener-Waterloo Latin Dance Communities, Lexi Salt

Theses and Dissertations (Comprehensive)

Given the systemic nature of gender-based violence in Canada, as well as the increasing popularity of Latin dance, it is important to better understand the particular and culturally-specific ways gender-based violence manifests itself within the Latin dance community. This research study examines the lived experiences of women of colour with gender-based violence in the Toronto and Kitchener-Waterloo Latin dance communities. Two groups of participants took part in semi-structured interviews: 14 women of colour dancers, and six “Power Players”, leaders in the Latin dance community who are in a position of power (e.g., instructors, organizers, DJs). The data was analyzed using …

Comparing Ionoregulation And Modes Of Nitrogen Excretion Across The Life Cycle Of Parasitic And Non-Parasitic Lamprey Species, Shannon Davidson

Theses and Dissertations (Comprehensive)

Abstract

Ionoregulation and nitrogenous waste (N-waste) metabolism in fishes has been extensively documented in teleosts and elasmobranchs, but less so in lampreys (Petromizontiformes). All lamprey species undergo metamorphosis which drastically changes their physiology and modes of feeding. However, differences in ionoregulatory mechanisms due to anadromous versus non anadromous life history strategies emerge following metamorphosis in different lamprey species. Furthermore, some species, such as anadromous juvenile sea lamprey (Petromyzon marinus), are parasitic and migrate to seawater (SW) to ingest blood protein from host fishes, while juveniles of freshwater (FW), non-parasitic species, such as the American brook lamprey …

Last Passage Time And Excursion Theory For Solvable Diffusions With Applications In Mathematical Finance, Yaode Sui

Theses and Dissertations (Comprehensive)

In this dissertation, we investigate the properties of last passage times and excursion theory in one-dimensional solvable diffusions, emphasizing their applications in financial modeling, particularly in option pricing. We derive closed-form formulas for the marginal distribution of last passage times and their joint distribution with process values, including the maximum and minimum of the process value. The focus is on time-homogeneous diffusions with various boundaries and imposed killing. Employing spectral expansion theory, we derive explicit formulas for distributions of last passage times in common processes such as Drifted Brownian Motion (BM), Squared Bessel (SQB), Ornstein-Uhlenbeck (OU), and Cox-Ingersoll-Ross (CIR) models. …

"Better Equipped"? Examining The Role Of Social Work In Clinical Countering Violent Extremism, David Yuzva Clement

Theses and Dissertations (Comprehensive)

Hate and violent extremism persist in communities, online environments, and societies across the globe. In addition to their most violent expressions, including hate crimes, extremist and terrorist violence, these phenomena wield severe negative, detrimental, traumatic, and intergenerational impacts. Grounded in evidenced-based policy, comprehensive prevention and intervention efforts, as well as the transfer of knowledge across scientific disciplines, a whole-of-society approach is fundamental to prevent and counter hatred, violence, and extremism. Although violent radicalization and associated societal problems are advancing at unprecedented speeds, preventing and countering violent extremism (P/CVE) is an emerging intervention field in behavioural health and social sciences. While …

Exit Through The Giftshop: Claims-Making And The Construction Of A Countercultural Brand, Cecil Mcglynn

Theses and Dissertations (Comprehensive)

Independent, online microcelebrity influencers are increasingly many people’s source of news. A popular group of these influencers, called the Alternative Influence Network (AIN) has come under scrutiny in recent years for collaborating with radical, far-right political actors to advance particular viewpoints (Lewis, 2018). While those within the AIN claim these outputs represent their freedom of speech, some researchers have voiced concern around the possibility of these influencers proliferating or even popularizing radical political ideals. Steven Crowder is among the most popular influencers in the AIN. He performs a daily show, ‘Louder with Crowder’, to his 5.8 million YouTube subscribers. In …

Understanding The Dynamics Of Food And Economic Development In The Community Of Kakisa, Northwest Territories, Canada, Laura Rodriguez Reyes

Theses and Dissertations (Comprehensive)

For Indigenous Peoples, the land embodies a source of cultural and spiritual well-being that is linked to their way of life and identities through divine and traditional connections. Unfortunately, colonial powers, the global food system, socioeconomic inequalities and environmental degradation are impacting northern Indigenous lands and food systems, leading to food insecurity. Nevertheless, communities are still thriving in the face of adversity. In the Northwest Territories, on the lands of Ka’a’gee Tu First Nations (KTFN) in the community settlement of Kakisa, people are growing food through vegetable gardens and greenhouses to support their vision of a resilient food system.

Through …

Mainstream Media Portrayal Of Banishment And Nation-Imposed Punishment, Keely Ormond

Theses and Dissertations (Comprehensive)

“In a traditional village, we wouldn’t have a teepee with no door on it and throw somebody in there. We wouldn’t cast them out, because banishment meant death. What we had to do was restore relationships” – Ryan Beardy (Thorpe, 2022).

The following project examines the representation of Indigenous traditions, customs, and issues in Canadian mainstream media. Specifically, this project is interested in the portrayal of banishment as an Indigenous practice in Canadian mainstream news outlets. This project is based on an interpretive paradigm informed by grounded theory and concepts of media framing, postcolonialism, settler colonialism and restorative justice. Nineteen …

Rates And Patterns Of Permafrost Thaw Induced Landcover Change At Scotty Creek, Canada, Mason Dominico

Theses and Dissertations (Comprehensive)

In the peatland-dominated regions of discontinuous permafrost in northwestern Canada, permafrost thaw is altering landscapes at rates without precedent in the historical record. The present study uses a combination of remote sensing and ground based methods to examine the rates and patterns of permafrost thaw and how such thaw is changing the form and function of the landscape. The area within a 4 km2 area of interest underlain by permafrost decreased from 51% in 1977 to 43% in 2010, and to 40% in 2018, indicating an increase in the permafrost thaw rate from 0.24% yr-1 between 1977 and 2010, and …

Three Essays On Risks In The Option And Cds Markets, Seyed-Erfan Sadeghi

Theses and Dissertations (Comprehensive)

This dissertation comprises three essays investigating topics in insurance on debt and equity. The first essay utilizes patent groups as an indicator of technological proximity and demonstrates that climate risk associated with technology-related firms can predict the next quarter’s Credit Default Swap (CDS) for the focal firm. The findings indicate that a 24 basis point (bps) change in the next quarter’s CDS can be attributed to the spillover effect from technology-related companies. Sentiment analysis reveals that this outcome is primarily driven by concerns related to regulatory factors. Importantly, these results remain robust even after accounting for firm-specific characteristics and industry-fixed …

Investigating The Mobility Of Arsenic In Subarctic Mining Pollution-Affected Peatlands Near Yellowknife, Northwest Territories, Jeremy Leathers

Theses and Dissertations (Comprehensive)

Arsenic (As) is a pollutant of global concern that is detrimental to human and environmental health. Between 1948 and 2004, mining operations near Yellowknife, NT released over 20,000 tonnes of As trioxide (As₂O₃) that continues to persist in the surrounding landscape. Although much effort has been put into studying the chemical forms, spatial distribution, ecological impacts, and environmental cycling of As in the area, more work is needed to determine the controls of As mobility between the terrestrial and aquatic components of the landscape. Soils are known reservoirs of legacy As that can release it downslope …

Impacts Of Environmental Stressors On Mummichog (Fundulus Heteroclitus) Growth And The Gh-Igf1 Pathway Using A Laboratory Bioassay, Olena Kuntyj

Theses and Dissertations (Comprehensive)

Using a flow-through laboratory bioassay, experiments investigated the effects of limited feeding, increased temperature, ammonium chloride (NH₄Cl), and 17α-ethinylestradiol (EE₂) on juvenile mummichog (Fundulus heteroclitus) growth. Weight measurements were taken every three days as the apical growth endpoint. Gene expression was examined by qPCR for genes in the GH (growth hormone)-IGF1 (insulin-like growth factor 1) pathway, including gh, igf1, and their receptors (ghra, ghrb, igf1ra, igf1rb). In Experiment 1, juvenile mummichog were exposed to excess or limited feed for 21 days. The limited-fed mummichog weighed less, were …

Understanding The Significance Of Object Recognition In Cowbirds: Exploring The Interplay Of Cognition, Social Behaviour And Reproductive Success, Eric Rushton

Theses and Dissertations (Comprehensive)

Every day, animals use cognitive processes to make decisions in their environment such as those regarding food sources, threats and mates. One such important process provides the ability to recognize objects and individuals in order to guide future actions. Since object recognition and individual recognition are related processes, they may be linked to social cognition and to fitness; links not commonly explored in the literature. In this thesis I seek to examine (1) how brown-headed cowbirds (Molothrus ater) attend to and react to novel objects in their environment and (2) how this ability to recognize objects is related …

Investigating The Use Of Voluntary Furloughs To Reduce Labour Costs: The Effect On Employee Effort, Kelsey Matthews

Theses and Dissertations (Comprehensive)

To quickly reduce costs in response to external shocks, firms often implement voluntary furloughs. In a voluntary furlough, employees decide whether to accept a reduction in their pay with a corresponding reduction in work hours. Despite the prevalence of voluntary furloughs in practice, it remains an empirical question how employees will respond to this cost reduction practice. The purpose of my dissertation is to investigate how the implementation of a voluntary furlough affects the subsequent effort of employees who volunteer and those who do not volunteer for a furlough.

I address my research question using two experiments where I manipulate …

Shifting Perspectives On Crime: Empathy, Cognitive Reappraisal, And Media Sources, Gillian Sherman

Theses and Dissertations (Comprehensive)

When reporting crime, media sources can influence public perception of the crime, the victim, and the perpetrator. They can also influence the justice policies that people endorse. With support growing for more community-oriented justice policies that allow for perpetrator reintegration (Maruna & King, 2009), it is important to understand how portrayals of crime may soften public judgements toward perpetrators without reducing concern for victims. In two studies drawing from empathy-attitude effect research (Batson et al., 1998) and emotion regulation theory (Gross, 1998) this research examines how media portrayals of a crime may cause people to change their perceptions of those …