Life Sciences Commons^™

Spatial And Temporal Dynamics Of Top Predators In A Large Lake, Silviya Vasileva Ivanova

Electronic Theses and Dissertations

Environmental degradation is the legacy of the Anthropocene era and maintaining ecosystem health is a major challenge for managers globally. Restoration ecology aims to improve ecosystem health through reintroduction and rehabilitation of important native species to maintain or increase biodiversity and achieve stable and resilient communities. Non-native species may affect reintroduction efforts through interactions in time and space. This dissertation proposes that understanding the spatio-temporal ecology of two species along with their energy demands and growth (i.e., bioenergetics), would provide key clues for untangling the complexities of species interactions and further the knowledge on influences of non-native species on native …

Survey Of Native Predatory Hemipterans And Assessment Of Nabis Americoferus Carayon (Hemiptera: Nabidae) As A Biological Control Agent Of Lepidopteran Tomato Pests, Andrew Laflair

Electronic Theses and Dissertations

Invasive species have become a grave threat to the economic viability of our global vegetable producers. Tomato pinworm Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) has expanded from its range originating from Peru to being established in nearly hundreds of countries, causing tomato production losses of up to 100% on occasion; however, it has not yet been found in Canada or the USA. Southwestern Ontario is a significant tomato producer making it a high risk from this invasive species. Efficient integrated control methods such as native biological control agents (BCAs) that avoid creating insecticide resistance are ideal. Surveys of Southwestern Ontario conservation …

Classification Of Breast Cancer Nottingham Prognostic Index Using High-Dimensional Embedding And Convolutional Neural Networks, Li Zhou

Electronic Theses and Dissertations

This work builds a prediction model for multi-omics breast cancer Nottingham Prognostics Index (NPI) classes. Rapid development in next-generation sequencing led to the ability to measure different biological indicators called multi-omics data. The availability of multi-omics data sparked the challenge of integrating and analyzing these various biological measures to understand the progression of the diseases. High-dimensional embedding techniques are used to present the features in the lower dimension, that is a 2-dimensional map. This thesis presents a supervised learning method used to predict breast cancer NPI. The objectives of this research are (i) build a diagnosis system for breast cancer …

Using Genetic Approaches To Study Local Adaptation And Reproductive Success In Snow Buntings (Plectrophenax Nivalis), Keta K. Patel

Electronic Theses and Dissertations

Genetic analyses can facilitate effective and timely conservation and management actions. Arctic-migratory species in particular are in need of conservation genetic insights as they are experiencing substantial population pressures due to the impact of climate change (and other anthropogenic effects) on processes that affect their survival and reproduction. Therefore, identification of genetic mechanisms driving population divergence and variation in reproductive fitness in such species is critical. The goal of this thesis is to examine reproductive isolation among breeding populations of an Arctic-migratory passerine, the snow bunting (Plectrophenax nivalis) and determine factors that drive local adaptation and variation in …

The Relationship Between Optic Nerve Sheath Diameter, Carotid Artery Pulsatility Index, And Blood Pressure In Healthy Adults, Rachel Marie Stone

Electronic Theses and Dissertations

Monitoring intracranial pressure (ICP) has become an important practice in patients with elevated ICP (e.g., traumatic brain injury) to improve patient outcome. However, little information exists surrounding chronic, but sub-clinical elevations in ICP, which may stem from classic cardiovascular risk factors, such as elevated blood pressure (BP). The current methods to assess ICP are invasive and costly; but optic nerve sheath diameter (ONSD) and blood flow pulsatility (pulsatility index; PI) are promising non-invasive techniques, both of which have been reported to strongly correlate with invasive measures of ICP in pathology. However, the interactions of BP, ONSD and PI in otherwise …

Utilizing An Integrated Approach To Explore Niche In A Complex Equatorial System, Danielle Orrell

Electronic Theses and Dissertations

Our ability to identify and understand the relationships and distributions of organisms in nature is key to exploring the rich tapestry of life seen on Earth. The term "niche" describes how animals partition resources in space and time, shaped by behavioural choices and environmental conditions. Iterations of niche over time have focused on different aspects of a species' ecological characteristics, from Grinnell’s initial study of songbird distribution (‘spatial niche’) in 1917 to Elton’s description of functional attributes shaping trophic position (‘trophic niche’). The fusion of these niche definitions formed Hutchinson’s n-dimensional niche hypervolume. The coexistence of …

Showcasing Strengths Of People With Disability To Stimulate Social Change, Kelly Carr

Electronic Theses and Dissertations

Objective: The overarching purpose of this dissertation was to understand the potential to stimulate social change through exposure to strengths-based contexts where people with disabilities displayed their skills. Through the intentional dismissal of a traditional, deficits-based approach to disability-related research, this dissertation highlighted the strengths of people with impairment as a means to resist disabling assumptions. As such, the actions of people with disability within these studies exist outside of imaginable possibilities produced by dominant social structures, and possess the capacity to shape the social world. By examining the impact of exposure to these three contexts, this dissertation sought to …

Experimental Analysis Of Fish Sensory Systems: From Behavioural Responses To Physiological Extremes, Roselia Ayala-Osorio

Electronic Theses and Dissertations

Fishes are surrounded by various types of stimuli in their habitats which provide important information about their environments. Here, I investigated how various types of stimuli can affect the behaviour and physiology of two freshwater species: the invasive round goby (Neogobius melanostomus) and the black bullhead (Ameiurus melas). In chapter 2, I tested for a synergistic response in the round goby to multimodal stimuli, by presenting acoustic, visual, and olfactory stimuli separately and simultaneously. The results showed a significant decrease in the average respiration rate during multimodal stimuli suggesting that a synergistic response to multimodal stimuli …

Rnp Granules In Toxoplasma Gondii: Function And Formation, Scott Roscoe

Electronic Theses and Dissertations

Toxoplasma gondii is an obligate intracellular parasite capable of infecting mammals, birds, reptiles, and fish. T. gondii only undergoes sexual reproduction in a feline host. In all other organisms the parasite reproduces asexually, either as fast growing tachyzoites or slow growing bradyzoites. Bradyzoites form latent cysts inside the host cell that can lay dormant for years and convert back to tachyzoites when the host’s immune system becomes weakened. Tachyzoites rapidly replicate in the host cell, eventually causing it to lyse. While extracellular, tachyzoites repress their own translation by phosphorylating the eukaryotic initiation factor eIF2α and form microscopically visible aggregates of …

“The Vehicle Was A Hockey Game”: A Holistic Approach To Aging For Older Men, Ryan Tomaselli

Electronic Theses and Dissertations

The many benefits of physical activity are well established. Nonetheless, there remains a need for qualitative research on aging and sports focused on the normalization of sport for older adults, and the increased opportunity for sport participation in older age. Aging and sport research, which has primarily focussed on older elite athletes, has found older adults value health-related benefits, social interaction, and resistance of the aging process through sport participation. However, research examining a broader scope of specific sport participation, such as hockey, in older age may provide a distinguished understanding of participation tied to meaning and lifestyle factors. Therefore, …

Variation In Oviposition Behaviour Of Blow Flies (Diptera: Calliphoridae) Due To Relative Humidity And Intraspecific Interactions, Theresa Tran

Electronic Theses and Dissertations

Blow flies are usually the first insects to arrive at carrion, using it to oviposit or breed. The behaviour to search for and accept a carrion resource as suitable for oviposition is influenced by abiotic factors, particularly temperature and humidity, as well as by the presence of other insects. My thesis focuses on the influence of relative humidity (RH), combined with intraspecific interactions, on oviposition choices of three blow fly species Lucilia sericata (Meigen), Phormia regina (Meigen), and Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae). Individual fly oviposition behaviour was measured on a temperature gradient (10-40°C) under high (75- 85%) and low …

Endogenous And Exogenous Factors Driving Bacterial Community Composition In Aquatic Ecosystems, Javad Sadeghi

Electronic Theses and Dissertations

The bacterial community (BC) composition in various habitats, ranging from ecosystems to host anatomy, plays an important role in determining the nature and role of BC function in the ecosystem or host. However, the relative importance of host endogenous and environmental exogenous factors in determining the composition of the BC in aquatic habitats (e.g., freshwater lakes, fish hosts) remains poorly understood. To address this knowledge gap, this thesis makes several contributions to the estimation of the relative effects of endo-exogenous factors in driving the BC composition in aquatic ecosystem. To test the impact of biotic and abiotic factors on aquatic …

Understanding Freshwater Ecosystems And Human Health Implications In Recreational Water Through Microbial Characterization, Source Tracking, And Sediment-Microbe Dynamics, Danielle Gleason

Electronic Theses and Dissertations

Contamination of natural aquatic ecosystems is a serious global concern as populations increase and the environment is impacted by climate change. Nonpoint source (NPS) contamination of allochthonous materials, such as sediments, nutrients, and microorganisms, is commonly introduced to a body of water through runoff and wash-off which cumulates over a large area, and is subsequently transported to surface waters (e.g., rivers, streams, lakes) and shorelines. The principal form of microbial contamination of water resources is often from fecal pollution derived from humans, domesticated animals, or wildlife, and contains a variety of human pathogens. There are also numerous factors (with limited …

Characterizing Endothelial Notch1 Release In Response To Changes In Vascular Wall Shear Stress, Matthew Indiana Badour

Electronic Theses and Dissertations

Murine and cell culture models have identified Notch1 as a novel endothelial mechanosensor that may exert a protective role for vascular adjustments in response to changes in vascular wall shear stress. However, in vivo studies in humans are lacking. Accordingly, we sought to characterize the concentrations of Notch1 extracellular domain (ECD) prior to, during, and following 20-min of altered shear stress in the brachial artery of ten young and healthy adults (6M/4F). Alterations in shear were induced by placing a pneumatic cuff inflated to 220mmHg around the left wrist. Cuffs were also placed below the axilla of both arms and …

Hand-Arm Vibration Exposure In Drummers, Dylan Durward

Electronic Theses and Dissertations

Due to the physically intense nature of the activity, drummers (i.e., percussionists who play the drum set) are exposed to a variety of factors, including hand-arm vibration (HAV), that put them at increased risk of developing playing-related musculoskeletal disorders (PRMDs). The purpose of this study was to examine HAV exposure in drummers through realistic playing scenarios. Specifically, this study examined vibrations (i.e., frequency-weighted RMS accelerations) recorded at the hands. Six male drummers played three songs of their choosing with one accelerometer placed on the right hand, then repeated the same three songs with the accelerometer placed on the left hand …

An Investigation Of Drummers’ Trunk And Upper Limb Muscle Activation Profiles During High-Velocity Cymbal Crashes, Nicolas Latreille

Electronic Theses and Dissertations

Drumming is a physically demanding activity, and skilled drummers share many physical and cognitive attributes with elite athletes. The “double pulse” muscle activation (DPMA) pattern is a motor control strategy that has been observed in athletes of sports involving ballistic movements, such as baseball, golf, and elite Mixed Martial Arts fighters. The two pulses are believed to function to increase striking velocity and effective mass, thus increasing force transfer onto the target. The purpose of this study was to examine the muscle activation patterns of highly skilled drummers for evidence of a DPMA during high-velocity cymbal crashes. Three highly skilled …

Elucidating Mechanisms For S-Nitrosoglutathione Reductase Activity And Control In Plants Using O-Aminobenzoyl-S-Nitrosoglutathione And A Novel Photo-Sensitive Probe, Leslie Ventimiglia

Electronic Theses and Dissertations

S-nitrosoglutathione reductase, (GSNOR) is widely accepted as the master regulator of stress through NO signaling and protein S-nitrosylation. GSNOR mediates stress response through the catalysis of its principal substrate S-nitrosoglutathione (GSNO). The instigation of various stressors in plants cause observable changes in plant phenotype, which are associated with changes in GSNOR activity. There are no current methods for measuring GSNOR activity directly in living plants. In this paper, a previously developed fluorogenic pseudo-substrate for human GSNOR, OAbz-GSNO, was applied to the Solanum lycopersicum plant model. OAbz-GSNO was identified as a promising novel pseudo- substrate to study changes …

Studies Of Chemosensory Responses In The Pharynx Of The Sea Lamprey (Petromyzon Marinus), Hasan Huseyin Polat

Electronic Theses and Dissertations

The sea lamprey is a basal vertebrate, and the oldest extant species with taste buds. The objective of this thesis was to study the chemosensory responses from the sea lamprey’s pharynx, which is located caudal to oral cavity and medial to seven lateral brachiopores. The pharynx contains taste buds that detect and respond to tastants to inform lampreys about gustatory factors in the environment. The location of these taste buds along the lateral surface of the pharynx was first determined using scanning electron microscopy. Then using electrophysiology, our recordings from these pharyngeal regions containing taste buds picked up responses from …

The Design And Testing Of Fluorescence-Based Sensors For Phosphate And Phosphonate, Sara Hassanzadehroknabadi

Electronic Theses and Dissertations

Inorganic phosphate (Pi) is an essential compound for all living things, as it serves as a component of nucleic acids and ATP, which are required for plant growth and proliferation. However, when excess Pi enters the aquatic environment, it has severe detrimental effects through the induction of harmful algal blooms (HAB), which negatively impact aquatic life, the quality of drinking water as well as recreational activities. It is therefore critical to have fast, sensitive, and inexpensive sensors for Pi that quickly and quantitively measure its concentration in a field setting.

Phosphonates or organophosphorus compounds are phosphoric acids possessing alkyl or …

Structure And Mechanics Of Biomembrane Mimics In The Presence Of Vitamin E, Mitchell Dipasquale

Electronic Theses and Dissertations

Over the course of this dissertation, the fundamental behaviours and interactions between various analogs of vitamin E and biologically-relevant membranes will be explored. These analogs include the biologically active form, α-tocopherol; the most naturally abundant form γ-tocopherol; an oxidized product, α-tocopheryl quinone; and the synthetic stabile form, vitamin E acetate.

Beginning in Chapter 1, a foundation in membrane biophysics is established from a historical progression of the field. The importance of biomembranes is argued and a deep connection is established between structure and function. Key structural features of lipid assemblies, and role of lipid composition is defined, and with the …

Mother Knows Best: Mechanistic Aspects Of Foraging Preference And Differential Arrestment Of Gravid Females: A Case Study On Blow Flies (Diptera: Calliphoridae), Vanessa Elizabeth Owen

Electronic Theses and Dissertations

Behavioural plasticity is a concept that describes a change in an organism’s behaviour due to their exposure to stimuli that differ from their usual environment. For instance, females of many insect species alter their behavioural responses when exposed to differing substances that they utilize for feeding, oviposition, and/or mating. Behaviours such as the frequency of walking, tasting, grooming exhibited by flies can be associated with the detection and acceptance of a suitable medium. For this thesis, the arrestment and behavioural response of gravid adult females of three species of blow flies (Diptera: Calliphoridae), Lucilia sericata Meigen, Phormia regina Meigen, and …

The Bouba/Kiki Effect On Gendered Objects In The Arabic Language, Ghadir Nassereddine

Electronic Theses and Dissertations

People are more likely to associate the nonword bouba with a round shape, and kiki with a sharp shape, an effect known as the Bouba/Kiki effect (BK) (Ramachandran & Hubbard, 2001). Relatedly, female names are associated with a round shape whereas male names are associated with a sharp shape (Sidhu & Pexman, 2015) and this effect extends to grammatically gendered nonwords in French (Sidhu, Pexman, & Saint-Aubin, 2019). These associations have not been examined in Arabic, or with real words with a grammatical gender. The present study addresses this gap by examining the influences of letter sound …