Master's Theses

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  • ItemOpen Access
    Modified half logistic - exponentiated Kumaraswamy distribution and applications
    (Faculty of Graduate Studies and Research, University of Regina, 2022-11) Xiao, Mei; Volodin, Andrei; Deng, Dianliang; Yao, Yiyu
    The statistical model of mixture distributions has become an important tool for analyzing complicated phenomena in the real world. This approach has a wide range of applications in the fields of biology, medicine, environment and engineering. Based on the characteristics of the Exponentiated Kumaraswamy model, researchers have carried out a series of explorations and studies. However, in order to provide a more appropriate model to support real-life applications and to make our data analysis more reliable, it is still meaningful to explore new models. Therefore, in this thesis, we propose a novel mixture model, which is a modified one based on the combination of the Type-II Half Logistic distribution and the Exponentiated Kumaraswamy distribution. We defined it as the Modified Half Logistic - Exponentiated Kumaraswamy (MHL-EK) distribution. Then, we will study its statistical properties, such as quantile function, moments, incomplete moments, etc. Next, maximum likelihood estimation will be used for the parameter estimation of the MHL-EK model. We will also present a related simulation study. Finally, we apply this model to three real data sets and give our analysis for them. The results show that the MHL-EK distribution is a relatively suitable model among the candidate models.
  • ItemOpen Access
    Resonator sensors integrated in bandpass filters for the detection and attenuation of interfering signals
    (Faculty of Graduate Studies and Research, University of Regina, 2023-03) Abdulkareem, Mariam Kikelomo; Laforge, Paul; Bais, Abdul; Dahle, Reena; Khondoker, Mohammad
    In microwave systems, RF front end devices are subjected to interference signal, this interference signal can damage the receiver end or disrupt wanted signals. This thesis proposes a method of sensing the interference signal by weak coupling a resonator to the filter. The proposed method employs a combline bandpass filter at 2 GHz center frequency at 5% bandwidth, which was designed on Advanced Design System (ADS) software and space mapping was performed to optimize the parameters. By weakly coupling the resonator to the filter, the interference signal of certain threshold power can be sensed. The resonator sensor designed are of two bandwidths, the narrower bandwidth resonator and the wider bandwidth resonator which are discussed in this thesis. During the design process of the wide bandwidth sensor the simulation results shows that a tunable attenuator can be realized. The filters is designed, fabricated and tested. The 3-pole filter with no sensor is fabricated and tested first while evaluating different ways to realize the vias from the top to bottom layers of the microstrip structure. It is determined that all methods show promise, though the best results are found using the soldered wire method. The narrow and wideband sensors are also fabricated and tested showing reasonable results when compared to the electromagnetic simulations. The wideband sensor design is tested with a circulator to demonstrate the proposed tunable attenuator design.
  • ItemOpen Access
    Experiences of professionals working with pre-adolescent children who are using psychoactive substances in Regina, SK
    (Faculty of Graduate Studies and Research, University of Regina, 2023-03) Nielsen, Rhonda Lee; Novotna, Gabriela; Fletcher, Kara; Gebhard, Amanda; Levine, Kathryn
    The purpose of this thesis research was to 1) explore the pathways to seeking and accessing support for substance use among pre-adolescents from the point of view of professionals working with children under age of 12, and, 2) examine how these professionals’ views on pre-adolescent substance use inform what services this population receives. The goal of the study was not only to understand how preadolescents access services for substance use but how the views of professionals assist or create barriers to accessing these services. The study used a qualitative, multiple case study method to interview four service providers, representing different jurisdictions and services, who worked with children and their families in Regina, SK. Five key themes emerged from the study: (1) the main pathway that leads to pre-adolescents receiving addictions services is through family involvement with child protection services; (2) a system of services within Regina, SK is fractured with many organizations providing mental health and addictions services but none specializing on the pre-adolescent population; (3) the perceptions of and beliefs about substance use among preadolescents’ that service providers have inform their practice; (4) service providers emphasize education and prevention to reduce pre-adolescent substance use; and (5) there are assumptions that Indigenous children are more likely to be involved in substance use than their non-indigenous counterparts.
  • ItemOpen Access
    Injury prevalence in open water swimmers
    (Faculty of Graduate Studies and Research, University of Regina, 2023-03) Tatlow, Dionne; Bruno, Paul; Reimer, Harold; Totosy de Zepetnek, Julia; Pasanen, Kati Sofia
    Open water swimming (OWS) is currently one of the fastest growing mass participation sports worldwide, and differs from pool swimming in that athletes swim in natural bodies of water such as lakes, oceans and rivers. Participation in this sport spans a wide range of individuals of all ages with a roughly equal sex distribution. No prior investigations have evaluated the musculoskeletal (MSK) injuries characteristic to the sport in a recreational capacity, and only one group has completed biannual surveillance in an elite population on three occasions. The purpose of the current study was to investigate the prevalence and explore possible risk factors associated with MSK injuries in non-elite OW swimmers during the COVID-19 pandemic (for circumstantial reasons). Participants were invited through a variety of social media channels and OWS community communications to complete a self-administered internet-based survey to evaluate the details of any injuries sustained within the previous 6-month period and various other demographic and training related details. 156 participants completed or partially completed the survey (95 female, 52 male, 9 did not disclose their sex; average age 47.7 (±12.4) years). The 6-month prevalence of MSK injury within this population was 30% (n=36), with the most commonly injured region being the shoulder (n = 25), and the second most common being the cervical spine (n = 6). A logistic regression was performed to assess the association between self-reports of injury (outcome variable) and various predictor variables. The final model yielded one significant predictor variable: participation in efforts to prevent injury (OR [95% CI] = 5.004 [1.356, 18.465], Wald =5.843, p = 0.016). Two marginally-significant predictor variables were age (OR [95% CI] = 1.039 [0.996, 1.084], Wald = 3.093, p = 0.079) and sex (female) (OR [95% CI] =2.614 [0.852, 8.021], Wald = 2.821, p = 0.093). Results of this study will be dispersed among the OWS community via academic and open-access publications, and may be used to guide injury prevention and rehabilitation efforts in this growing population.
  • ItemOpen Access
    The relationship between neurocognitive performance and sport-related musculoskeletal injury
    (Faculty of Graduate Studies and Research, University of Regina, 2022-08) O'Neill, Erica M.B.; Bruno, Paul; Dorsch, Kim; Mang, Cameron; Lebrun, Constance
    Background: The number of sport-related musculoskeletal (MSK) injuries continues to rise even with an increase in prevention programs. The potential relationship between neurocognitive performance and sport-related MSK injury has begun to emerge in the literature, with results suggesting that athletes with lower baseline neurocognition sustain more injuries compared to those with higher baseline neurocognition. Purpose: This study aims to build on the previous literature by investigating this relationship while controlling for variables that have been well-documented as predisposing factors for injury (i.e., previous MSK and brain injury). Methods: A total of 87 participants from the University of Regina Rams football team were included in the study. Baseline Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) data (Verbal Memory Composite, Visual Memory Composite, Visual Motor Speed Composite, Reaction Time Composite, and Impulse Control Composite), MSK injury history, concussion history, and number of games participated were all gathered. Acute lower extremity (LE) MSK injuries that occurred over the course of the six-game, 11-week season were recorded and included in the analysis. Two statistical analyses were conducted: linear and logistic regression. Both regression analyses used a hierarchical method with step 1 including independent variables of previous LE MSK injury and previous concussion history. Step 2 involved the addition of the number of games played as an independent variable and step 3 involved the addition of all neurocognition measures as independent variables (Verbal Memory, Visual Memory, Visual Motor, Reaction Time, and Impulse Control). The dependent variable for the linear regression was the severity of injury, measured as the number of days from time of injury to full return to sport with no restrictions. The dependent variable for the logistic regression was injury versus no injury. Results: Sixteen (18.4%) of the participants suffered an injury over the course of the season, with the average (standard deviation [SD]) injury severity being 3.77 (10.24) days. Step 2 (number of games played) had the largest impact on both regression models. Having played 1-2 games in the six-game season was the only independent variable to make a statistically significant contribution to predicting injury severity (β = .338, p = .005) and injury occurrence (OR [95%CI] = 19.880 [2.239, 176.477], Wald = 7.202, p = .007). The final logistic regression model correctly classified 18.8% of injured participants and 98.6% of non-injured participants. Conclusion: Playing in 1-2 games in a six-game season was the only statistically significant independent variable at predicting both musculoskeletal injury occurrence and severity. There are several limitations to this study affecting the generalizability of the results. The assumptions of linearity, homoscedasticity, and normality were not met in the data, and there was a small number of injuries due to the small sample size and short follow-up period. More research is needed in this area, particularly involving other populations outside of collegiate level football athletes, longer study periods, and the potential relationship between executive functioning and MSK injury.
  • ItemOpen Access
    The lived experience of parental stress of fathers of a child with Autism Spectrum Disorder
    (Faculty of Graduate Studies and Research, University of Regina, 2022-09) MacSorley, Cody Allan; Jeffery, Bonnie; Sorensen, Michele; Loutzenhiser, Lynn; McLuckie, Alan
    The purpose of this study was to expand the current understanding of father parental stress through an interpretive phenomenological analysis of fathers of children with Autism Spectrum Disorder’s lived experience. Parents of children with Autism Spectrum Disorder have been found to experience higher levels of stress than both parents of typically developing children and all other special needs children that have been researched to date. The experience of parental stress for parents of children with Autism Spectrum Disorder has primarily looked at the experience of mothers, with limited studies exploring the experiences of fathers. The current study interviewed six fathers who have a child between the ages of six and 12 with Autism Spectrum Disorder. Through analyses of the interviews, five superordinate themes were identified: (1) Covid-19 Pandemic, (2) Isolation, (3) Self-Efficacy, (4) Stressors, and (5) Coping. Participants highlighted the breakdown of their limited supports during the global pandemic, and the sense of loss, isolation, and frustration this created. Participants also identified negative perceptions of their self-efficacy, tied to vague perceptions of success as a father. They experienced isolation, due to stigma and ignorance of their child’s needs and feeling that there is a lack of dedicated supports for fathers. Participants discussed high levels of stress due to the chronic nature of their child’s needs and fear of what their future holds as fathers. Lastly, participants discussed limited options for coping due to guilt when trying to utilize strategies and supports, as well as negative perceptions of masculinity that created barriers and stigma to accessing supports.
  • ItemOpen Access
    ‘Return on[boarding] investment’: Exploring volunteer onboarding experiences on newcomer behaviours and implications for volunteer board performance
    (Faculty of Graduate Studies and Research, University of Regina, 2023-03) Lott, Korinne Kimberly; Kulczycki, Cory; Dubnewick, Michael; Genoe, Rebecca; Kerwin, Shannon
    Exploration of the onboarding experiences (OE) of newcomer volunteers in a volunteer leadership context is lacking in current volunteer management and governance research. Through a lens of socialization and self-efficacy principles, this study aims to address whether OE can be an interceding influence for newcomer behaviours and motivations. The level at which an individual is onboarded (Bauer, 2010) and the exchange between existing employees and newcomers, affects attitudinal aspects of the individual toward the role that they uphold (Sluss & Thompson, 2012). Increasing the knowledge base about the implications of onboarding practices within a volunteer context allows for more discernment surrounding appropriate considerations to effectively optimize the acquisition of knowledge and information for newcomers within a volunteer board, as well as how to enhance the interactional exchange between new individuals and existing members. Seven semi-structured interviews (approximately 45 – 60 minutes in length) were conducted with newcomer volunteers of non-profit sport or recreational organizations. New board members were considered to be within one year of their tenure, and were recruited to participate through various petitioned means. The study adopted an inductive approach complemented with thematic analysis (Braun & Clarke, 2006) as a way to parse-out and construe the data collected from each of the participants. Findings within this study highlighted a number of themes and sub-themes that may impact a newcomer’s OE. These themes (i.e., process, information and organizational knowledge acquisition, original intent to participate, and person-organization fit) are aspects for sport and recreation organizations to consider when onboarding new individuals to a group. Overall, this project sought to provide cogency toward the knowledge and experiences that foster individual group members’ motivations and actions at a volunteer leadership level. It begins to address the onboarding experiences in a volunteer context and questions if we can adapt similar principles and understanding to volunteers compared to a workplace setting.
  • ItemOpen Access
    Sandwiched between best practice and morality policy: Harm reduction's pursuit for legitimacy on a contentious frontier
    (Faculty of Graduate Studies and Research, University of Regina, 2023-03) Fisher, Rayna Mary Louise; Milne, Lise; Fletcher, Kara; Halpape, Katelyn; Fornssler, Barb
    Canada is in the midst of a public health crisis. In 2020 and 2021, jurisdictions across Canada, including Saskatchewan, had a record number of deaths due to drug toxicity and overdose. In 2022, statistics are on pace to once again set records. The current system, including legislation and service delivery, is not working, and addressing substance use and the overdose crisis will require an innovative and comprehensive approach. The literature highlights the merit of harm reduction (HR) services for substance use both in mortality reduction and in treating substance use; yet, investment in and implementation of HR services remains stark. The conversations by many public leaders perpetuate misnomers about substance use and HR, and these conversations go largely unchallenged. People who use drugs and the overdose crisis remains an issue on the margins. HR is a contentious issue that is politically tied. There is a significant dearth of literature regarding public opinion of HR philosophy and interventions, particularly in the Saskatchewan context. It is reasonable to believe that without public support, further investment will remain stalled. Thus, it is important to develop a baseline of public opinion in order to highlight particular groups that may benefit from targeted education and/or awareness campaigns. This project uses a mixed methods approach to explore the public opinion of HR services in Saskatchewan. The research highlights the level of understanding, opinions and attitudes the general public has of HR both as a philosophy and of HR’s particular interventions. A commentary is provided on the current political climate in Saskatchewan and the case for HR services as a legitimate player in the addictions field. Suggestions for targeted public education regarding HR are provided.
  • ItemOpen Access
    An exploratory consideration of cognition and physiology in athletes following concussion
    (Faculty of Graduate Studies and Research, University of Regina, 2023-03) Lillie, Garrett Richard; Dorsch, Kim; Neary, Patrick; Mang, Cameron; Brigham, Mark
    A mild traumatic brain injury (mTBI), colloquially known as a concussion, is an injury of the brain that often results in significant functional impairment for days, weeks, or even months. While the most common symptoms of concussion have been well documented and studies frequently note a deficit in either higher-level cognitive functioning and autonomic physiological control, there is a lack of research describing the effect of concussion on executive functioning and heart rate variability (HRV). The aim of this study was to address gaps in literature by describing changes in an individual’s executive functioning and physiology simultaneously following a concussion using two investigative approaches, using the theory of neurovisceral integration as a guiding framework. Secondary data from University of Regina athletes was used to examine baseline executive functioning (measured by Neurotracker®) and athlete HRV transformed from ECG. These results were subsequently compared to the same measures postinjury. Prior to review of data from the 2019-2020 academic year, there was an expectation that occurrence of a concussion would be associated with a decrease in Neurotracker® performance, Mean R-R intervals (Mean R-R), and Root-Mean-Square-Difference of successive R-R intervals (RMSSD) while also being associated with increases in Low-Frequency/High-Frequency (LF/HF) ratio and Standard Deviation 2/Standard Deviation 1 (SD2/SD1) ratios. Across a sample of eight participants, only one participant experienced the expected change in variable while the two participants that experienced symptoms the longest, featured smaller deviations from their baselines. My study was exploratory in nature and suggests directions for future research.
  • ItemOpen Access
    Parenting and social media: Exploring parental understanding of adolescent social media use
    (Faculty of Graduate Studies and Research, University of Regina, 2023-01) Anspach, Chandra Lynn; Fletcher, Kara; Chalmers, Darlene; Jeffery, Bonnie; Wright, Laura
    Social media (SM) has become an integral part of adolescent socialization. SM is widely accessible through advanced technology with resulting demands for constant connection. Existing research has focused on the negative aspects of SM while highlighting the need for an understanding of how to mitigate risk factors associated with adolescent SM use. Parental mediation strategies have been noted in existing research as an important factor in lessening risks or negative outcomes related to adolescent SM use. Using interpretive phenomenology analysis (IPA), parental understanding of adolescent SM use was explored to gain insight into how parents understand and experience mediation strategies related to adolescents’ involvement in the virtual world. Findings indicate parents do understand mediation strategies and have employed varying strategies inclusive of monitoring, restrictions, and open communication. Further, findings suggest parents accept SM and embrace the associated challenges of adolescents’ involvement in the online world, adapting to changes and adjusting mediation strategies to meet the needs of their adolescent and family. This thesis asserts parents are creating a parenting philosophy that focuses on relationships, with potential for SM to provide important teaching opportunities and improved communication with their young people. Improving understanding of parental experiences regarding adolescent SM use and how parents navigate this socio-cultural shift can provide helpful information for social work practice to support parents and families navigating this foreign world.
  • ItemOpen Access
    The effect of relapsing-remitting Multiple Sclerosis on gait variability and regularity
    (Faculty of Graduate Studies and Research, University of Regina, 2022-10) Kohrs, Russell Alexander; Barden, John; Bruno, Paul; Mang, Cameron; Donkers, Sarah
    Multiple Sclerosis (MS) is an inflammatory and neurodegenerative autoimmune disease that destroys the myelin sheath of the central nervous system. Gait impairments are one of the most debilitating and concerning symptoms for PwMS that can significantly impact an individual’s quality of life. Gait changes in people with MS (PwMS) have often been quantified using basic spatiotemporal parameters; however, research into more complex measures of gait variability, such as the measurement of small fluctuations that occur during the gait cycle (e.g., fractal-scaling index (FSI)), and the measurement of the consistency of trunk-based acceleration waveforms (gait regularity), have been shown to provide deeper insights into gait deficits in other neurological conditions. This research has demonstrated the potential to provide better predictors for important clinical factors such as fall risk. The purpose of this study was to investigate the relationship between the aspects of gait variability and regularity in people with relapsing-remitting MS and to compare the results to a healthy, age- and sex-matched control group. Using a cross-sectional study design, thirty participants were recruited (13 MS (12F; 44.9 ± 14.0 years; Median EDSS (IQR): 2.5 (2.0 – 4.5)); 17 controls (15F; 40.3 ± 10.9 years). Each participant completed a ten-minute walking test at a self-selected speed around a 200m track. Gait patterns were assessed using a tri-axial accelerometer placed on the lower back. From the raw accelerometer data, gait variability was assessed as the coefficient of variation (COV) of step time and stride time, step regularity and stride regularity, and the FSI of stride time. PwMS were found to walk with significantly higher step time COV and lower anteroposterior (AP) step regularity and AP and mediolateral (ML) stride regularity than the control group. PwMS were also found to walk significantly slower and take shorter steps than the control group. Strong associations between the differences in speed and gait variability were also found. This association appeared to produce a powerful combined effect on the locomotor function of PwMS, but gait speed also appeared to partially influence the significant differences seen in gait regularity. The findings of this study suggest that PwMS walk with a significant amount of variability and demonstrate greater bilateral asymmetry and impairment of movement consistency during the braking and propulsive phases of gait than healthy controls. Future research is needed to better understand the relationship between MS, gait speed and measures of gait variability.
  • ItemOpen Access
    Effect of creatine monohydrate supplementation in aging adults with type II diabetes
    (Faculty of Graduate Studies and Research, University of Regina, 2023-02) Bailie, Robert David; Candow, Darren; Totosy de Zepetnek, Julia; Little, Jonathan; Gillen, Jenna B.
    Sarcopenia generally refers to the age-related reduction in muscle strength and physical performance, with greater decreases found in aging adults with type II diabetes (T2D). Supplementing with creatine, a nitrogen-containing compound formed from reactions involving the amino acids arginine, glycine and methionine, is an intervention which have been shown to increase muscle strength, endurance and physical performance in healthy aging adults. Further, creatine supplementation has been shown to influence glucose metabolism in individuals with T2D. However, the effects of creatine supplementation in aging adults with T2D in unknown. Therefore, the purpose of this study was to examine the effects of creatine supplementation on measures of blood glucose, muscle strength, endurance and tasks of physical performance in aging adults with T2D. Using a double-blind, repeated measures design, participants were randomized to supplement with creatine monohydrate (CR: n = 4; 71 ± 7 years, 94.3 ± 13.9 kg, 165.2 ± 6.0 cm; 0.3 g·kg -1·day -1) or placebo (PLA: n = 3; 74 ± 2 years, 95.2 ± 7.3 kg, 159.3 ± 9.5cm; 0.3 g·kg -1·day -1 maltodextrin) for seven consecutive days. Prior to and following supplementation, variables measured were fasting blood glucose, muscle strength (1-repetition maximum leg press, chest press, hand-grip), muscle endurance (leg press and chest press; maximal number of repetitions performed at 50% baseline 1-repetittion maximum), and tests of physical performance (6-minute walk test, sit-to-stand chair test). Results showed that both groups experienced similar changes in all measures over time. In conclusion, in this preliminary investigation, creatine supplementation had no effect on blood glucose or measures of muscle strength, endurance and physical performance in aging adults with T2D. Key words: sarcopenia, blood glucose, strength, physical performance
  • ItemOpen Access
    The effects of chronic stress on allocentric versus egocentric spatial memory
    (Faculty of Graduate Studies and Research, University of Regina, 2023-03) Ziemer, Julie Lianne; Sykes Tottenham, Laurie; Gordon, Jennifer; Sharpe, Donald; Mang, Cameron
    Spatial navigation is a skill that is critically dependent upon an organism’s ability to remember object locations and orient themselves in an environment. Two strategies commonly examined in spatial memory research are allocentric (ALLO) and egocentric (EGO). Individuals using an ALLO strategy orient with respect to a cognitive map of distal environmental boundaries, while those using an EGO strategy orient with respect to themselves and singular proximal landmark cues. Stress affects spatial memory, but it is unclear whether one strategy more than the other enhances processing in the context of chronic stress. The present study examined the effects of chronic stress on ALLO and EGO spatial memory. A final sample of forty-two male participants completed a chronic stress measure and then a spatial memory dual-strategy navigation task with ALLO and EGO cues. Participants’ preferred strategy was determined by identifying which strategy they relied upon to guess the previously viewed location of an invisible target. Participants’ EGO and ALLO performance was determined by examining how accurate their guesses were on trials for which only one cue type was an accurate predictor. Chronic stress variables (frequency and severity) from chronic stressors that occurred during childhood as well as overall chronic stress were examined as potential predictors of visuospatial strategy performance in a series of regression analyses. Regression analyses were also used to examine chronic stress variables (frequency and severity) from chronic stressors that occurred during childhood as well as overall chronic stress as potential predictors of strategy preference scores. A greater number of chronic stress events was associated with a greater preference for EGO strategy use, but no relationships were found when examining chronic stress severity, performance, and childhood chronic stressors. The findings suggest that chronic stress—specifically overall chronic stress—may be an important factor related to visuospatial memory preference.
  • ItemOpen Access
    Characterization of Cenomanian-early Turonian bentonites in southwestern Saskatchewan through lithostratigraphy and chemostratigraphy analysis
    (Faculty of Graduate Studies and Research, University of Regina, 2023-01) Zhang, Yuting; Coulson, Ian; Qing, Hairuo; Raharimahefa, Tsilavo; Yang, Daoyong
    Volcanic eruptions can disperse tephra over a wide area, and may result in deposition of ash far from their sources. For example, ash from the 1980 eruption of Mt. St. Helens volcano in Washington State was observed falling upon Regina, Saskatchewan. Bentonite is a name for widely distributed beds of altered ash that have the potential to be used as isochronous horizons in lithostratigraphic correlation, much in the same way that tephrochronology is applied to young volcanic deposits. Numerous bentonite horizons are preserved within Late Cretaceous strata of western Canada and northern USA, and several widespread layers delineate unit or formation boundaries (e.g., the Clay Spur bentonite, X-bentonite). This thesis outlines studies of Cenomanian-early Turonian bentonite across southwestern Saskatchewan, with an aim not only to document these, but to rigorously test whether bentonite can help in refining the regional stratigraphic framework of an area. Specifically, bentonite occurring within the Belle Fourche and Second White Specks formations of southwestern Saskatchewan were investigated using lithological, well log and mineral chemistry data. As evidenced in previous research, near pristine magmatic mineral grains can be preserved in bentonite, despite the changes that accompanied its burial and lithification. Fresh grains of mica and feldspar were identified in bentonite from the study area. Analysis of these crystals record specific and unique compositions for each layer and can provide strong discriminants to identify or correlate layers of bentonite. Moreover, the character of determined mica and feldspar compositions furnish clues to their magmatic sources. Three regional cross-sections are presented herein, highlighting lithological and stratigraphic associations for bentonite within and across the study area. These derive from the examination of 6 principal lithologies, from across 13 wells and aided by detailed studies and interpretation of 56 geophysical wireline logs in Geoscout software. Fourteen bentonites were recorded from the Late Cretaceous strata, with a subset of 35 samples characterized in terms of well log responses, lithological characteristics, and mineral compositions. The 14 layers may be subdivided into four compositional groups, reflecting their volcanic sources (i.e., calc-alkaline, alkaline, peraluminous and sub-alkaline group). Also provided is a database of bentonite, that summarizes key characteristics of each bed to be used as a reference in future studies or for a regional stratigraphic correlation. The results of this study show that bentonite lithostratigraphy and chemostratigraphy have great promise in local and regional correlation and that bentonite is readily identifiable through a combination of core examination and geophysical well log studies. Analysis of crystals within can provide a fingerprint for each bentonite that may help to refine local stratigraphy, especially useful when other methods are inconclusive; for example, a lack of microfossils or facies changes across an area.
  • ItemOpen Access
    Gamma-decay spectroscopy of sodium-26
    (Faculty of Graduate Studies and Research, University of Regina, 2022-09) Saei, Nastaran; Grinyer, Gwen; Mobed, Nader; Teymerazyan, Aram; Robbins, Leslie
    In November 2017, an experiment was performed at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF, whose goal was to perform a precise measurement of the beta decay half life of 14O. Beams of 26Na, which are readily available at ISAC, were also used during that experiment for performing rate-dependent calibrations and performance tests of the GRIFFIN spectrometer for detecting gamma rays. The decay of 26Na provides an ideal test case to verify the methodology of the data analysis and ensure that GRIFFIN can provide accurate results, with minimal losses, even at relatively high-counting rates. Given that a previous high-precision experiment was previously performed using the 8π gamma-ray spectrometer [1] to determine the 26Na half-life, gamma-ray intensities and beta-decay branching ratios this decay offers and excellent choice to search for the possibility of rate-dependent losses associated with the novel GRIFFIN data-acquisition system. In this analysis, a high-precision study of 26Na that mirrors the previous work is presented. The detailed gamma-ray spectroscopy and resulting relative gamma-ray intensities and beta-decay branching ratios were determined using the beta-gamma and gamma-gamma coincidence spectroscopy. A detailed comparison with the results from Ref. [1] confirms almost all of the findings in that work, which provides confidence that GRIFFIN can be operated at counting rates of at least 6.4 kHz per crystal without any significant data loss.
  • ItemOpen Access
    A study of mirrors for an Aerogel Ring Imaging Cherenkov detector
    (Faculty of Graduate Studies and Research, University of Regina, 2022-08) Pereira Ferrazzi, Bruno; Kolev, Nikolay; Barbi, Mauricio; Huber, Garth; Coulson, Ian
    In this thesis, I present a study of the mirror system for the Aerogel Ring Imaging Cherenkov device (ARICH). The ARICH will be installed in the Experiment to Measure the Production of Hadrons At a Testbeam in Chicagoland (EMPHATIC) whose goal is to measure hadron scattering and production cross sections on a broad range of nuclear targets with different beam momenta that are important for neutrino production at the GeV scale. These measurements will be relevant for the Tokai to Kamioka (T2K) and the upcoming Hyper-Kamiokande Experiment (Hyper-K) and the Fermilab-based Deep Underground Neutrino Experiment (DUNE). This thesis demonstrates that the mirror increases the angular acceptance of detector, but it also increases the number of Rayleigh scattered photons in the aerogel that will reach the plane of the photodetectors as a form of background. I study multiple mirror materials based on their reflectance curves in order to minimize the reflection of the background without compromising the reflection photons necessary to reconstruct the Cherenkov ring signal. Based on this method I find that the Miro-Silver material from the Anomet company provides the best signal-to-background reflection efficiency. On the experimental side, I have performed the design and testing of the structure that will be responsible to support the mirror inside the ARICH detector. The structure is based on a 3D printed frame structure and aluminum plates to keep the mirrors flat. A testing apparatus was built using a laser and photodiodes to scan the surface of the mirror in the search of deformations or deviations from specular reflection condition. The results show consistency that indicate the method appliedcan be used to test the mirror and the supporting structure.
  • ItemOpen Access
    Aquatic ecosystems’ responses to past human activities in the neotropics
    (Faculty of Graduate Studies and Research, University of Regina, 2022-08) Patino Restrepo, Luisa Fernanda; Velez Caicedo, Maria; Raharimahefa, Tsilavo; Kerr, Samantha
    Lake systems are essential for the environment and human populations. Nevertheless, human activities have strongly modified aquatic ecosystems, and many lakes have been affected by anthropogenic stressors, including eutrophication, acidification, increased sediment load, among others. In the last years, the study of the environmental history of lakes has increased, as well as the need for assessing the changes due to anthropogenic activities on aquatic systems. However, the information about how freshwater ecosystems in the neotropics have responded to natural forcings e.g., climate variations and or anthropogenic activities, is still scarce. Sediments accumulated in lakes provide a useful archive that can be used to reconstruct past responses to changes in climate and anthropogenic activities. In this study, the diatom assemblages of two lakes located in areas with histories of human influence, are used as proxies to reconstruct the limnological history of these neotropical ecosystems to track the magnitude of the impacts of climate variability and anthropogenic activities. The outcomes of this study shows that the diatom assemblages of both lakes respond to variations in the physical and chemical parameters of the lake, such as turbidity, pH, and nutrient content, likely from anthropogenic activities. Natural factors, possible precipitation, appear to have had influence on the variations in the diatom assemblages of both lakes, especially at the beginning of the record. Furthermore, in both lakes it was possible to identify changes related to the European arrival. It is hoped that this study supports the management and conservation policies of aquatic ecosystems and gives insights into the possible responses to climate change that are expected to occur in the future.
  • ItemOpen Access
    Implementation of crystal mapping and energy calibration procedures for PET block detectors with pixelated scintillators
    (Faculty of Graduate Studies and Research, University of Regina, 2022-08) Parikh, Jay T.; Teymerazyan, Aram; Kolev, Nikolay; Laforge, Paul
    The prevailing high-resolution Positron Emission Tomography (PET) block detector architecture uses pixelated scintillating crystals coupled to a position sensitive photomultiplier tube (PS-PMTs) or a silicon photomultiplier (SiPM) array. In such detector designs a light guide layer between the finely segmented scintillating crystal array and coarsely segmented photosensitive layer is introduced, which allows to distribute the scintillation light over several elements of the photosensor. Commonly, such detectors employ some form of analog signal multiplexing to minimize the number of readout electronics channels and employ Center of Gravity (CoG) approach to calculate the positions of gamma ray interactions. The list mode data used by a typical PET image reconstruction software uses scintillating crystal array element positions as surrogate for the location of interaction of annihilation gamma ray with the detector. The positions of gamma ray interactions with a PET block detector, obtained through a Center of Gravity (CoG) calculation, are encoded into corresponding scintillating crystal array element position through a lookup table – crystal map. In this work I focus on implementing a crystal mapping procedure, based on K-Means algorithm, for PET block detectors using pixelated scintillating crystals, and apply said procedure to preliminary data obtained from a block detector used in the next generation plant and soil-microbiome PET imaging system, BioPET, that employs state of the art Gadolinium Aluminum Gallium Garnet (GAGG) scintillator arrays. However the crystal mapping procedure presented in this work should be in principle applicable to any PET block detector employing similar design. Furthermore, crystal mapping procedure is essential for performing per-scintillating-crystal-array-element energy calibration of the annihilation gamma ray energy spectra collected by the block detectors, a necessary step as light collection efficiencies from elements of scintillating crystal array in a PET block detector are non-uniform and highly location dependent within the scintillating array.
  • ItemOpen Access
    An efficient Internet of Things (IoT) device fingerprinting approach using machine learning
    (Faculty of Graduate Studies and Research, University of Regina, 2022-10) Osei, Richmond; Louafi, Habib; Mouhoub, Malek; Shahriar, Nashid; Al-Anbagi, Irfan
    Internet of Things (IoT) usage is steadily becoming a way of life. IoT devices have applications in smart homes, factories, and farming. Thousands of IoT devices are hooked up to the cyberspace each day. However, the increased usage of IoT devices comes with many security concerns due to their small and constrained build-up; consequently, perpetrators could target an IoT device as an access point to attack the whole network. Further, the number of IoT device manufacturers keeps expanding by the day, although a high number of these manufacturers have less or little knowledge about IoT security. Therefore, a comprised IoT device in a network presents a vulnerability for an attacker to exploit the network. Notwithstanding, relying on the most typical approaches to securing IoT devices is becoming increasingly complex and less prone to attackers. To determine the identities (fingerprints) and nature of these devices, Mobile Network Operators (MNOs) often analyze the traffic generated by these devices (legitimate, faulty, or malicious). When a new IoT device is attached to the network and is compromised, the fingerprinting process takes quick action to determine the real identity of the device. This thesis presents an effective way to fingerprint IoT devices using machine learning. Many security benefits come with fingerprinting IoT devices on a network, including automatic vulnerability patching, the introduction of behaviour-based anomaly detection, and dynamic attack mitigation. A better way of securing IoT devices is by using a machine-learning algorithm to fingerprint IoT devices in the network accurately. This process should be achieved using minimal features to reduce the amount of data to process, which is critical in real-time prediction applications. Focusing on the optimal (minimal) features of IoT devices requires accurately fingerprinting the device. In this study, new features were generated from the original features of an IoT dataset that contains IoT network traffic. These new features, extracted using reduction methods, were then trained on selected machine learning algorithms, and the prediction quality of each model was analyzed. The obtained results are appealing. Indeed, with only five (5) features instead of the 17 features from the original dataset, the proposed solution is capable of accurately fingerprinting IoT devices with an accuracy of 97%, as measured using the Precision, Recall, and Harmonic mean metrics.
  • ItemOpen Access
    Life history traits of Prussian carp (Carassius gibelio) in Saskatchewan, Canada: Age, growth, and reproduction on an advancing invasion front
    (Faculty of Graduate Studies and Research, University of Regina, 2022-09) Menard, Jayme; Somers, Christopher; Finlay, Kerri; Manzon, Richard; Green, Stephanie
    The Prussian carp (Carassius gibelio) is one of the most invasive fish species in Europe, and it was recently discovered in North America in Western Canada. Our knowledge of basic life history parameters, such as growth rate and mode of reproduction for Prussian carp in their new invasive range, is currently limited. In addition, Prussian carp were only recently discovered in Saskatchewan, but how long have they been in the province, and the stage of invasion is uncertain. Prussian carp can use two modes of reproduction: (1) gonochoristic, involving males and females; and (2) gynogenesis, whereby populations consist of only triploid females that steal sperm from other fish species. Newly introduced populations of Prussian carp tend to be all female and triploid, but their ploidy and mating system in Canada has not been determined. In addition, when and where spawning occurs in newly colonized waterways is completely unknown. Given these important knowledge gaps in fundamental aspects of Prussian carp biology, I focused on describing the life history traits of Prussian carp in Saskatchewan using a mixture of field and lab approaches. I found that Prussian carp in Saskatchewan are slow growing compared to other invasive populations worldwide, and take up to 2x as long to reach sexual maturity. The oldest fish I collected in Saskatchewan was 16 years old in Lake Diefenbaker, and 13 years old in Stockwell Lake, indicating that Prussian carp have been established in the province for many years and were undetected. Similar to well established populations in other parts of the world, Saskatchewan Prussian carp had mixed ploidies with diploid (2n), triploid (3n), and tetraploid (4n) individuals intermixed. In Lake Diefenbaker only female fish were detected, but males were present in Stockwell Lake in low quantities (0.14:1; M:F). Emergence of young of the year Prussian carp in Lake Diefenbaker began in early July and continued through August; however, most spawning in this area likely occurred during mid-June. The timing of spawning and habitat use by juvenile Prussian carp overlaps with that of a variety of native sucker and shiner species. My findings suggest that Prussian carp are well established in Saskatchewan and are likely in the invasive spread phase of invasion. They pose an immediate threat to native biota in Canada locally in Saskatchewan, and via dispersal and colonization of other locations.