Understanding adolescent physical activity participation. A program evaluation of a body positive resistance training program

The increase of physical inactivity and sedentary behaviour among adolescents is alarming. With decreasing physical activity rates among Canadian adolescents there is a major concern to their overall health and wellbeing. Regular physical activity has been shown to have many health benefits for adolescents; therefore, it is important to understand current barriers and motivators influencing adolescents’ participation in physical activity. The primary purpose of this study was to evaluate a program designed to increase physical activity participation for adolescents at risk for chronic illness. Three group interviews were conducted with thirteen adolescents who participated in a 10-week chronic disease prevention program that included resistance training in a body positive environment. Additionally, I maintained a reflective journal documenting aspects of the research process and observations from the weekly sessions. Through providing a safe physical activity program, this study assessed the effects of a body positive approach to physical activity with adolescents. This thesis provides an understanding of barriers and motivators that adolescents experience in relation to physical activity participation, aiding in future program design

When mothers disengage: stories from women who have gone from participants to observers in their autistic child’s education

There exists a knowledge gap in our understanding of why some mothers of Autistic children resist engaging fully with their children’s school-based teams, despite the body of research supporting the benefits of constructive family-school relationships. This thesis investigates the narratives of five mothers through the lens of Bronfenbrenner’s ecological systems theory and the feminist theoretical framework of nonunitary subjectivity. The results were analysed for themes inductively using a constant comparative model. The qualitative data gained from this exploration finds that the participants disengage from their children’s school teams after years of experience, intense efforts, discouragement, cumulative stress, and perspective shifts. School leaders should consider that any promotion of re-engagement needs to transpire through a culturally responsive, trauma-informed lens that prioritises relationship building, empathy, and suspended judgement. The research also suggests that more flexible hiring practices could be of benefit. Further research in this area exploring the perspectives of educators, fathers, and more marginalised groups is recommended

k-fold cross-validation can significantly over-estimate true classification accuracy in common EEG-based passive BCI experimental designs: an empirical investigation

In passive brain computer interface (BCI) studies, a common approach is to collect data from mental states of interest during relatively long trials and divide these trials into shorter “epochs” to serve as individual samples in classification. While it is known that using k-fold cross-validation (CV) in this scenario can result in unreliable estimates of mental state separability (due to autocorrelation in the samples derived from the same trial), k-fold CV is still commonly used and reported in passive BCI studies. What is not known is the extent to which k-fold CV misrepresents true mental state separability. This makes it difficult to interpret the results of studies that use it. Furthermore, if the seriousness of the problem were clearly known, perhaps more researchers would be aware that they should avoid it. In this work, a novel experiment explored how the degree of correlation among samples within a class affects EEG-based mental state classification accuracy estimated by k-fold CV. Results were compared to a ground-truth (GT) accuracy and to “block-wise” CV, an alternative to k-fold which is purported to alleviate the autocorrelation issues. Factors such as the degree of true class separability and the feature set and classifier used were also explored. The results show that, under some conditions, k-fold CV inflated the GT classification accuracy by up to 25%. It is our recommendation that the number of samples derived from the same trial should be reduced whenever possible in single-subject analysis, and that both the k-fold and block-wise CV results are reported

Crab by-product hydrothermal carbonization and hydrochar characterization

In Atlantic Canada, fisheries and seafood processing are major industries contributing to the local economy. Shellfish industry, particularly snow crab, make up a significant waste stream from this industry. The high moisture content of the crab by-product makes it challenging to valorize. Hydrothermal carbonization (HTC), a hydrothermal process involving biomass in the presence of water, is a simple and effective means of valorizing high moisture biomass, which could negate all or part of the drying process. The main product of HTC is a solid called hydrochar, which has various applications (for example, fuel and bioadsorbent). In this thesis, the hydrochar properties produced from snow crab (Chionoecetes Opilio) are studied to determine the effect of operating conditions on crab hydrochar and assess the best applications. Chapter 2 of this thesis includes a review of the literature on the existing hydrothermal carbonization of various feedstock from lignocellulosic non-lignocellulosic to marine biomass. The findings show that the valorization of marine biomass, especially crab by-products, is rarely studied. Moreover, many of the studies use pre-treatment methods such as deproteinization, deacetylation, or demineralization, which can be unsuitable and costly for remote locations of processing plants. Chapter 3 is the bulk of the thesis experimental work and discussion. Crab hydrochar was synthesized from snow crab processing by-product using HTC over a range of temperatures (180 - 260 °C), residence times (0.5 – 3 h), and water to biomass ratios (2 - 4). In addition to the experiments performed using dried, ground RC, WC was also tested at specific operating condition to study the effects of drying. The hydrochar yield was determined, and feedstock and the hydrochar were compared via ash content (wt %, db), surface area (m² /g), surface groups (FTIR), trace elements, pH, composition (CHN, wt%, db), and minerals (XRD). In general, the hydrochar (solid) yield decreased as water ratio and temperature increased, reflecting the feedstock's increased thermal and water decomposition. Hydrochar has a higher ash content than the feedstock, making it less desirable for fuel application. The increase in hydrochar BET surface area (maximum of 26 m² /g at 260 °C, water ratio 3 and 30 min) and the presence of functional groups in the hydrochar showed potential to facilitate chemisorption as a bioadsorbent. The hydrochar also may suitable for soil amendment application due to its minerals content and soil pollutant adsorption capability

Baseline benthic plastic debris assessment and intertidal survey in Iqaluit, Nunavut Canada for 2016 and 2017

Marine plastic pollution is a global issue affecting food webs, humans, and the natural environment. There is limited marine plastic pollution research in Iqaluit and the Arctic in general. This thesis focuses on Iqaluit, Nunavut targeting intertidal and marine benthic debris in areas with high human activity such as fishing and hunting areas, shipping locations, and the proximity to the city. Data includes sampling from October 2017 as well as previously collected (2016) sediment grab samples and seafloor video collection. Benthic grab samples and seafloor video were examined for anthropogenic debris including microplastics (5mm). An intertidal survey was conducted at low tide to determine the amount and types of land-derived plastic debris that may enter Frobisher Bay as a possible point source for marine plastic pollution. Determining the abundance of both microplastics and macroplastics will create a baseline for marine plastic pollution found in Frobisher Bay, NU. This thesis includes protocols for sampling in extreme environments and provides an analysis of methods that are replicable for monitoring benthic and terrestrial marine debris. No significant changes in benthic marine debris occurred during 2016 and 2017. The results indicate a baseline of 0.002 plastics/mL of benthic debris, 0.055 plastics/minute for benthic seafloor video, and 0.379 plastics/m2 of shoreline debris for marine debris in the Frobisher Bay area and Iqaluit, Nunavut

The spatial distribution and composition of microplastics in Placentia Bay, Newfoundland and Labrador

As part of a baseline study for Placentia Bay, one of Newfoundland's prominent fishing regions, I investigated the spatial distribution and characteristics of microplastics. I collected water samples from the surface at nine open-water locations and sediment samples at six locations in the sediment layer. Microplastics were examined under a microscope, and a subset of samples underwent Raman microspectroscopy for chemical identification To tailor methods specifically to the water and sediment samples from Placentia Bay, I conducted method tests. Published methods proved unreliable, as a lack of standardized methodology was evident. Water column samples required an extended digestion time of 24 hours with hydrogen peroxide and acetic acid due to their POC-rich nature. In sediment samples, microplastics were isolated using a sodium tungstate dihydrate solution. . The highest concentrations of microplastics in the water column were identified on the eastern side of the bay, with fibers being the predominant shape and polyethylene as the dominant polymer type. Raman spectroscopy was employed to confirm microplastics and evaluate the reliability of visual identification. 50% of fragments and 21% of fibers were non-plastic, highlighting the limitations of relying solely on visual identification for characterizing microplastics

The effect of opioids on biomechanical parameters of bone

Bone is a dynamic and living tissue that continuously undergoes change throughout life. Current literature indicates that prolonged opioid exposure disrupts bone remodeling by inhibiting osteoblast activity and predisposing individuals to increased bone failure resistance. Our study builds upon proof-of-principle data from a pre-clinical rabbit-opioid model system to investigate 1) the biomechanical impact of opioid exposure on bone failure resistance, 2) the relationship between cross-sectional geometric values and fracture patterns, and 3) how microstructural parameters inform bone failure resistance. We hypothesize that bone specimens from opioid animals will demonstrate increased bone failure resistance, increased medullary area and cortical porosity, decreased cortical area and a diminished cellular network (e,g., lacunar parameters). Twenty-one male, skeletally mature New Zealand White rabbits were divided into three groups of seven animals each: morphine sulphate, fentanyl, and controls for eight weeks of experimental drug treatment. A multi-modal approach was used to collect data including high- resolution imaging (SRμCT) and biomechanical 3-point bend tests. Analyses revealed significantly greater cortical porosity in the morphine group compared to fentanyl and control animals. When examining the graphs visually, opioid groups demonstrated greater cortical and medullary areas and diminished markers of structural competence compared to controls. Analyses revealed that increased lacunar parameters are associated with reduced structural competence. Increased cortical area and medullary area are positively correlated with structural competence. Ultimately, evidence suggests that opioid exposure stimulated cellular dysregulation of the remodeling process and increased bone failure resistance in the opioid experimental groups

Numerical and experimental studies of high-temperature superconducting systems

The objective of this thesis is to study the correlated behaviour of electron and lattice dynamics in the high-temperature cuprate superconductors. In particular, we are interested in the lattice (i.e., structural and phonon) and electronic dynamics in these systems and how they may influence the driving mechanisms of high-Tc superconductivity. We do this through two methods: numerical calculations on the two-dimensional Hubbard model and inelastic light scattering experiments. For the numerical component of this work, we compute the static and dynamical longitudinal charge and spin susceptibilities as functions of real frequency on a twodimensional square lattice with weak-coupling for the t − t' − U Hubbard model via a perturbative, diagrammatic approach. In the static case, the spin susceptibility is dominated by q = (π, π) spin fluctuations that are largest near half-filling, while the charge susceptibility has a clear multi-peak structure with a minimum located at the van Hove singularity of the non-interacting dispersion, a feature not observed in the commonly employed random-phase approximation. For dynamical charge and spin susceptibilities, we plot the dispersion for each respective collective electronic excitation on the real frequency axis. These excitations were found to split into separate modes surrounding the van Hove singularity, only to merge again in the longwavelength limit. From an experimental standpoint, these results will prove useful for those studying electronic excitations as our calculations indicate that electron doped cuprates should be probed at higher energies in order to detect spin and charge excitations in comparison to the hole doped cuprates. For the experimental aspect of this work, we study the single-crystal Bi₂Sr₂CaCu₂O₈₊δ (Bi-2212) cuprate by Brillouin light scattering spectroscopy at room-temperature. We study the acoustic phonon behaviour in the normal state and gain further information on the structural dynamics which currently remain unresolved. From spectra ii collected with an excitation source of 532 nm, we identify the Rayleigh surface mode, a longitudinal resonance mode, and six bulk acoustic modes (four quasi-transverse and two quasi-longitudinal), contrary to the typically expected three. From bulk spectral peaks, the extracted frequency shift and linewidth were used to determine the optical extinction coefficient-to-refractive index ratios. These ratios were subsequently used to obtain the extinction coefficient, penetration depth, optical absorption coefficient, and complex dielectric function, and were found to be 5 − 7 times larger than those obtained from optical interference measurements. The number of bulk modes observed in the Brillouin data suggests Bi-2212 is an incommensurate composite crystal consisting of two weakly interacting sublattices. Further analysis of the Brillouin data allows us to assign the two independent sublattices as Bi₂Sr₂O₄ and CaCu₂O₄, calculate the hypersound velocity of the observed surface and bulk acoustic phonon modes, and derive an expression relating the bulk crystals longitudinal acoustic phonon velocity to the bulk longitudinal acoustic phonon velocities corresponding to the two sublattices. Finally, we determined the elastic constants C₁₁, C₂₂, C₃₃, C₄₄, C₅₅, C₁₂, and C₂₃ and related sublattice elastic constants. Overall, the utility of the experimental work presented in this thesis is multi-fold. Firstly, it has refined the acoustic phonon velocities, and subsequently the elastic constants, of Bi-2212 which have received little attention. Secondly, our derived expression relating the bulk and sublattice longitudinal velocities will aid in expanding upon the model of incommensurate composite crystals and the study incommensurate crystallography in general. Lastly, and most importantly, our experimental verification that Bi-2212 is comprised of two interacting sublattices alludes to a highly non-trivial optic phonon structure and the existence of low-lying optic phonon modes. Identification of such modes may play an important role in understanding the driving mechanisms surrounding high-Tc superconductivity

Unconventional fruits and their by-products as sources of phenolic compounds: effect of microencapsulation on biological activities and bioefficiency

Nutraceuticals are capable of providing health benefits beyond basic nutrition and are used in the medicinal form. This product category has played a pivotal role in health promotion, being associated with a reduced incidence of metabolic syndrome conditions such as obesity, type 2 diabetes, some types of cancers, and cardiovascular ailments. Typically, bioactive compounds serve as the foundational elements of nutraceutical development due to their ability to positively modulate human physiology. Among the widely explored bioactive classes, phenolic compounds stand out as a heterogeneous group with several subclassifications and varying degrees of complexity. Recognized as potent free radical scavengers, their antioxidant mechanisms allow these molecules to mitigate oxidative stress and protect vital biomolecules, including lipids (e.g., LDL-cholesterol) and nucleic acids (e.g., DNA). Phenolic compounds can also form complexes with proteins, granting them the ability to inhibit metabolic enzymes such as a-glucosidase and pancreatic lipase, which are highly active in people living with type 2 diabetes and obesity, respectively. Due to their potential impact on human health, novel phenolic sources have been procured for the development of nutraceuticals and functional food ingredients. Phenolics are abundant in plant material and are part of food linked with health promotion, including fruits and vegetables, cereals and grains, legumes, nuts, herbs and spices. Among phenolic-rich fruits, several types remain unexplored and could hold great potential for commercialization if their nutraceutical potential is confirmed. Examples include tropical fruits like guava, butiá, and jerivá, as well as sea buckthorn, a berry recently introduced to some locations in North America, including Newfoundland. Besides the edible portions of these fruits, their by-products (e.g., seeds, skins) could also serve as sources of phenolic compounds, opening new possibilities for the upcycling of these usually discarded fractions. In this study, the phenolic composition of guava, jerivá, butiá, Newfoundland’s sea buckthorn, and their by-products was assessed. All studied fruits, along with their residual portions, proved to be rich sources of phenolics, distributed in the free, esterified, and insoluble-bound fractions. Guava pulp and its processing discards (a homogenous fraction composed of peels, seeds, and residual pulp) were abundant in ellagic and gallic acid derivatives, similar to jerivá and butiá pomace and seeds. Sea buckthorn pomace and seeds were also high in ellagitannins and the seeds containing a substantial amount of (+)-catechin. Phenolic extracts from these fruits demonstrated strong antiradical activity and ferric reducing capacity, which was positively reflected in their in vitro ability to inhibit oxidative damage to human LDL-cholesterol and supercoiled plasmid DNA, as well as to hamper the activity of a-glucosidase and pancreatic lipase. However, these bioactivities were significantly affected when powdered samples of the studied fruits and their residues underwent in vitro gastrointestinal digestion, simulating the oral, gastric, small and large intestinal phases. After small intestinal digestion, most samples exhibited low phenolic bioaccessibility, meaning that their phenolic concentration was considerably diminished, consequently reducing their effectiveness in protecting key biological markers. To address this, phenolic extracts from the studied fruits and their by-products were microencapsulated by freeze-drying using maltodextrin as a wall material. The microencapsulated extracts were subjected to in vitro digestion, revealing a considerable increase in intestinal phenolic bioaccessibility compared to their unencapsulated counterparts. This increase was coupled with higher protection against LDL-cholesterol and DNA oxidative damage, as well as higher inhibitory activity toward a-glucosidase and pancreatic lipase in most cases. Microencapsulation also proved beneficial to the cellular antioxidant activity (CAA) of differentiated human adenocarcinoma (Caco-2) cells promoted by phenolic extracts, showing greater stability of CAA levels than unencapsulated extracts across tested extract concentrations. On the other hand, microencapsulated phenolic extracts demonstrated an augmented prooxidative effect and cytotoxicity toward cervical cancer (HeLa) cells compared to their unencapsulated versions, suggesting a potential anticancer effect. Thus, the microencapsulation of phenolic extracts obtained from guava (pulp and processing waste), butiá, jerivá, and sea buckthorn (pomace and seeds) potentiated the nutraceutical prospects of these underutilized sources of bioactive compounds. These findings support further exploration of unconventional fruits for therapeutic purposes, and future work needs to test microencapsulated phenolic extracts in vivo while studying the underlying mechanisms through which phenolic compounds exert their health-promoting effects

Urban and rural perceptions toward the reintrocution of wood bison in Alaska, USA

This study investigates public perceptions surrounding wood bison restoration in Alaska, differentiating responses by urban and rural settings and hunting participation. It establishes and compares baseline levels of social acceptability norms, trust in the wildlife agency, and perceived impacts (both risks and benefits) of the reintroduction. The study encompasses two major urban centers and four rural villages near the release site. Data collected through mail surveys and structured interviews are analyzed using t-tests and ANOVA, with reported effect sizes. Overall, the public holds positive views regarding bison and its management. Notably, rural participants display higher levels of trust, management support, and expectations of impacts. Conversely, urban hunters exhibit the lowest endorsement of proposed management actions. These findings underline the importance of tailored communication and education efforts to address variations in perceptions among distinct groups and ensure effective conservation strategies. The study also highlights potential opportunities and recommendations tied to the wood bison reintroduction initiative