Now showing items 1-20 of 588

    • Reporting of adverse events in muscle strengthening interventions in youth: A systematic review

      Mack, Diane E.; Anzovino, Daniel; Sanderson, Malcolm; Dotan, Raffy; Falk, Bareket (2023-03-06)
      To document the extent to which AEs, resulting from intervention studies targeting muscle-strengthening training (MST) in youth, are reported by researchers.
    • Skin blood flow responses to acetylcholine and local heating at rest and 60%V O2max, and associated nitric oxide contribution, in boys vs. girl

      Massarotto, Rafaele Joseph; Hodges, Gary J.; Woloschuk, Alexandra; O'Leary, Deborah; Dotan, Raffy; Falk, Bareket (2023-03-06)
      To determine sex-related differences in the skin-blood-flow (SkBF) response to exercise, local heating, and acetylcholine (ACh) in children. Additionally, the contribution of nitric oxide (NO) was examined. Methods: Forearm SkBF during local heating (44˚C), ACh iontophoresis, and exercise (30 min cycling, 60% OV 2max) was assessed, using Laser-Doppler fluxmetry, in 12 boys and 12 girls (7–13 yrs old), with and without NO synthase inhibition, using Nω-nitro-L-arginine methyl ester (L-NAME) iontophoresis. Results: Local-heating-induced and ACh-induced SkBF increase were not different between boys and girls (Local heating: 1445±900% and 1432±582% of baseline, , p=.57; ACh: 673±434% and 558±405% of baseline, respectively, p=0.18). Exercise-induced increase in SkBF was greater in boys than girls (528±290 and 374±192% of baseline, respectively, p=0.03). L-NAME blunted the SkBF response to ACh and during exercise (p<0.001), with no difference between sexes. Summary: SkBF responses to ACh and local heat stimuli were similar in boys and girls, while the increase in SkBF during exercise was greater in boys. The apparent role of NO was not different between boys and girls. It is suggested that the greater SkBF response in the boys during exercise is related to greater relative heat production and dissipation needs during this exercise intensity. The response to body-size-related workload should be further examined.
    • (Im)mobilités

      Parayre, Catherine; Serfas, Shawn; Savoie, Paul; Cozea, Angela; Ayouti, Thomas; Christie, Alexander; Hauck, Nicholas (small walker press, 2023)
      Five authors of fiction-criticism – Paul Savoie, Angela Cozea, Thomas Ayouti, Alexander Christie, and Nicholas Hauck – explore motifs – urban life, travel, seascapes, illness – developed in a creative-writing piece by Catherine Parayre. The book illustrations show artworks from a series titled Pseudo-fiction by Canadian artist Shawn Serfas and Catherine Parayre. Editor: Nicholas Hauck. In French.
    • Child-Adult differences in antagonist muscle coactivation: A systematic review

      Woods, Stacey; O'Mahoney, Caragh; McKiel, Andrew; Natale, Laurel; Falk, Bareket (Elsevier, 2023)
      Antagonist coactivation is the simultaneous activation of agonist and antagonist muscles during a motor task. Age-related changes in coactivation may contribute to observed differences in muscle performance between children and adults. Our aim was to systematically summarize age-related differences in antagonist muscle coactivation during multi-joint dynamic and single-joint isometric and isokinetic contractions. Electronic databases were searched for peer-reviewed studies comparing coactivation in upper or lower extremity muscles between healthy children and adolescents/young adults. Of the 1083 studies initially identified, 25 met eligibility criteria. Thirteen studies examined multi-joint dynamic movements, 10 single-joint isometric contractions, and 2 single-joint isokinetic contractions. Of the studies investigating multi-joint dynamic contractions, 83% (11/13 studies) reported at least one significant age-related difference: In 84% (9/11 studies) coactivation was higher in children, whereas 16% (2/11 studies) reported higher coactivation in adults. Among single-joint contractions, only 25% (3/12 studies) reported significantly higher coactivation in children. Fifty six percent of studies examined females, with no clear sex-related differences. Child-adult differences in coactivation appear to be more prevalent during multi-joint dynamic contractions, where generally, coactivation is higher in children. When examining child–adult differences in muscle function, it is important to consider potential age-related differences in coactivation, specifically during multi-joint dynamic contractions.
    • A need for speed: Objectively identifying full-body kinematic and neuromuscular features associated with faster sprint velocities

      Vellucci, Chris L.; Beaudette, Shawn M. (Frontiers Media SA, 2023-02-03)
      Sprinting is multifactorial and dependent on a variety of kinematic, kinetic, and neuromuscular features. A key objective in sprinting is covering a set amount of distance in the shortest amount of time. To achieve this, sprinters are required to coordinate their entire body to achieve a fast sprint velocity. This suggests that a whole-body kinematic and neuromuscular coordinative strategy exists which is associated with improved sprint performance. The purpose of this study was to leverage inertial measurement units (IMUs) and wireless surface electromyography (sEMG) to find coordinative strategies associated with peak over-ground sprint velocity using machine learning. We recruited 40 healthy university age sprint-based athletes from a variety of athletic backgrounds. IMU and sEMG data were used as inputs into a principal components analysis (PCA) to observe major modes of variation (i.e., PC scores). PC scores were then used as inputs into a stepwise multivariate linear regression model to derive associations of each mode of variation with peak sprint velocity. Both the kinematic (R2 = 0.795) and sEMG data (R2 = 0.586) produced significant multivariate linear regression models. The PCs that were selected as inputs into the multivariate linear regression model were reconstructed using multi-component reconstruction to produce a representation of the whole-body movement pattern and changes in the sEMG waveform associated with faster sprint velocities. The findings of this work suggest that distinct features are associated with faster sprint velocity. These include the timing of the contralateral arm and leg swing, stance leg kinematics, dynamic trunk extension at toe-off, asymmetry between the right and left swing side leg and a phase shift feature of the posterior chain musculature. These results demonstrate the utility of data-driven frameworks in identifying different coordinative features that are associated with a movement outcome. Using our framework, coaches and biomechanists can make decisions based on objective movement information, which can ultimately improve an athlete’s performance.
    • No Justice, Only Struggle

      Zvyagintseva, Lydia; Ribaric, Tim (University of Toronto Libraries - UOTL, 2023-01-09)
      2022 has been a year of overlapping crises. The so-called “Freedom Convoys” paralyzing Canadian communities, the COVID-19 pandemic continuing to cause excess death and disability, the war in Ukraine, the intensifying effects of climate change, and increasing inflation have all signaled that we find ourselves in a new era, one that can be described as authoritarian capitalism. In this article, we view the restructuring of Canadian universities as yet another facet of authoritarian capitalism, which uses overlapping crises to further proletarianize library labour and fully subsume it into the “learning factory.” Using Sandro Mezzadra and Brett Neilson’s theorization of the politics of capital’s operations, we examine the library restructuring processes taking place at four Canadian universities: Alberta, Brock, Laurentian, and OCAD. We view the reorganizations taking place there as efforts on behalf of university administrators to use the intensification of global forces of capitalism to exploit academic librarian labour. Ultimately, we argue that Canadian librarians are witnessing both formal and real subsumption in Canadian universities, precipitated by the overlapping crises outlined earlier. As a result, we insist that librarians need to develop a politics of struggle to build collective consciousness and action in the face of authoritarian capitalism.
    • Bearded dragons (Pogona vitticeps) with reduced scalation lose water faster but do not have substantially different thermal preferences.

      Sakich, Nicholas B; Tattersall, Glenn J (2021-06-17)
      Whether scales reduce cutaneous evaporative water loss in lepidosaur reptiles (Superorder Lepidosauria) such as lizards and snakes has been a contentious issue for nearly half a century. Furthermore, while many studies have looked at whether dehydration affects thermal preference in lepidosaurs, far fewer have examined whether normally hydrated lepidosaurs can assess their instantaneous rate of evaporative water loss and adjust their thermal preference to compensate in an adaptive manner. We tested both of these hypotheses using three captive-bred phenotypes of bearded dragon (Pogona vitticeps) sourced from the pet trade: ‘Wild Types’ with normal scalation, ‘Leatherbacks’ exhibiting scales of reduced prominence, and scaleless bearded dragons referred to as ‘Silkbacks’. Silkbacks on average lost water evaporatively at about twice the rate that Wild Types did. Leatherbacks on average were closer in their rates of evaporative water loss to Silkbacks than they were to Wild Types. Additionally, very small (at most ~1°C) differences in thermal preference existed between the three phenotypes that were not statistically significant. This suggests a lack of plasticity in thermal preference in response to an increase in rate of evaporative water loss, and may be reflective of a thermal ‘strategy’ as employed by thermoregulating bearded dragons that prioritises immediate thermal benefits over the threat of future dehydration. The results of this study bolster an often-discounted hypothesis regarding the present adaptive function of scales and have implications for the applied fields of animal welfare and conservation.
    • Faculty of Mathematics and Science 1st Graduate Research Day Conference, 2022

      FMS Graduate Research Day (FMS GRaD) is an academic conference open to all FMS students with a mandate to celebrate and communicate Brock University research and teaching. The FMS GRaD 2022 conference was hosted by the Dean’s office of the Faculty of Mathematics and Science and Graduate Mathematics and Science Society at Brock University. With 57 presenters and over 300 attendees this first FMS GRaD held on September 16th 2022 strengthened the STEM research community and highlight the research and profile of FMS graduate student research programs.
    • Parameter selection for modeling of epidemic networks

      Dube, Michael; Houghten, Sheridan; Ashlock, Daniel (IEEE, 2018-5)
      The accurate modeling of epidemics on social contact networks is difficult due to the variation between different epidemics and the large number of parameters inherent to the problem. To reduce complexity, evolutionary computation is used to create a generative representation of the epidemic model. Previous gains from the use of local, verses global, operators are further explored to better balance exploration and exploitation of the genetic algorithm. A typical parameter study is conducted to test this new local operator and the new method of point packing is utilized as a proof of concept to perform a better search of the parameter space. All experiments from both approaches are tested against nine epidemic profiles. The point-packing driven parameter search demonstrates that the algorithm parameters interact substantially and in a non-linear fashion, and also shows that the good parameter settings are problem specific.
    • Edit metric decoding: Return of the side effect machines

      Houghten, Sheridan; Collins, Tyler K.; Hughes, James Alexander; Brown, Joseph Alexander (IEEE, 2018-5)
      Side Effect Machines (SEMs) are an extension of finite state machines which place a counter on each node that is incremented when that node is visited. Previous studies examined a genetic algorithm to discover node connections in SEMs for edit metric decoding for biological applications, namely to handle sequencing errors. Edit metric codes, while useful for decoding such biologically created errors, have a structure which significantly differentiates them from other codes based on Hamming distance. Further, the inclusion of biologically- motivated restrictions on allowed words makes development of decoders a bespoke process based on the exact code used. This study examines the use of evolutionary programming for the creation of such decoders, thus allowing for the number of states to be evolved directly, not witnessed in previous approaches which used genetic algorithms. Both direct and fuzzy decoding are used, obtaining correct decoding rates of up to 95% in some SEMs.
    • A deep learning pipeline to classify different stages of Alzheimer's disease from fMRI data

      Kazemi, Yosra; Houghten, Sheridan (IEEE, 2018-5)
      Alzheimer's disease (AD) is an irreversible, progressive neurological disorder that causes memory and thinking skill loss. Many different methods and algorithms have been applied to extract patterns from neuroimaging data in order to distinguish different stages of Alzheimer's disease (AD). However, the similarity of the brain patterns in older adults and in different stages makes the classification of different stages a challenge for researchers. In this paper, convolutional neuronal network architecture AlexNet was applied to fMRI datasets to classify different stages of the disease. We classified five different stages of Alzheimer's using a deep learning algorithm. The method successfully classified normal healthy control (NC), significant memory concern (SMC), early mild cognitive impair (EMCI), late cognitive mild impair (LMCI), and Alzheimer's disease (AD). The model was implemented using GPU high performance computing. Before applying any classification, the fMRI data were strictly preprocessed. Then, low to high level features were extracted and learned using the AlexNet model. Our experiments show significant improvement in classification. The average accuracy of the model was 97.63%. We then tested our model on test datasets to evaluate the accuracy of the model per class, obtaining an accuracy of 94.97% for AD, 95.64% for EMCI, 95.89% for LMCI, 98.34% for NC, and 94.55% for SMC.
    • Hierarchical clustering and tree stability

      Saunders, Amanda; Ashlock, Daniel; Houghten, Sheridan (IEEE, 2018-5)
      Hierarchical clustering via neighbor joining, widely used in biology, can be quite sensitive to the addition or deletion of single taxa. In an earlier study it was found that neighbor joining trees on random data were commonly quite unstable in the sense that large re-arrangements of the tree occurred when the tree was reconstructed after the deletion of a single data point. In this study, we use an evolutionary algorithm to evolve extremely stable and unstable data sets for a standard neighbor-joining algorithm and then check the stability using a novel type of clustering called bubble clustering. Bubble clustering is an instance of associator clustering. The stability measure used is based on the size of the subtree containing each pair of taxa, a quantity that provides an objective measure of a given trees hypothesis about the relatedness of taxa. It is shown experimentally that even in data sets evolved to be stable for a standard neighbor joining algorithm, bubble clustering is a significantly more stable algorithm.
    • Representation for Evolution of Epidemic Models

      Dube, Michael; Houghten, Sheridan; Ashlock, Daniel (IEEE, 2019-6)
      Creating a representation capable of generating personal contact networks that are most likely to exhibit specific epidemic behavior is difficult due to the inherit volatility of an epidemic and the numerous parameters accompanying the problem. To surpass these hurdles, evolutionary algorithms are used to create a generative solution which generates personal contact networks, modeling human populations, to satisfy the epidemic duration and epidemic profile matching problems. This representation is entitled the Local THADS-N representation. Two new operators are added to the original THADS-N system, and tested with a traditional parameter sweep and a parameter selection method known as point packing on nine epidemic profiles. Additionally, a new epidemic model is implemented in order to allow for lost immunity within a population thus increasing the length of an epidemic.
    • We Are Not Pontius Pilate: Acknowledging Ethics and Policy

      Hughes, James Alexander; Hannah, William; Kikkert, Peter; MacKenzie, Barry; Ashlock, Wendy; Houghten, Sheridan; Ashlock, Daniel; Stoodley, Matthew; Dube, Michael; Brown, Rachel; et al. (IEEE, 2020-12-01)
      A new AI system is being developed to optimize vaccination strategies based on the structure and shape of a community's social contact network. The technology is minimally constrained and not bound by preconceived notions or human biases. With this come novel outside the box strategies; however, the system is only capable of optimizing what it is instructed to optimize, and does not consider any ethical or political concerns. With the growing concern for systematic discrimination as a result of artificial intelligence, we acknowledge a number of relevant issues that may arise as a consequence of our new technology and categorize them into three classes. We also introduce four normative ethical approaches that are used as a framework for decision-making. Despite the focus on vaccination strategies, our goal is to improve the discussions surrounding public concern and trust over artificial intelligence and demonstrate that artificial intelligence practitioners are addressing these concerns.
    • The September He Remembers

      Bolz, Cedric (2023-01-04)
      The Summit Series, a best-on-best hockey tournament played between the former-Soviet and Canadian men’s teams, occupies an outsized role in the Canadian sporting imagination. The September He Remembers: Josef Kompalla and the 1972 Summit Series reframes this famous Series in sport history through the story, experiences, and memories of Josef Kompalla, a German referee who played a key role in the events as one of the few esteemed officials selected to officiate during the Series. Given Kompalla’s important place in the history of the Summit Series, one of the most mythologized and celebrated tournaments in Canadian sport history, it should come as a surprise that his perspective on the events has not been previously documented. In this book, Bolz seeks to rectify this longstanding oversight through intrepid archival creation and analysis, as well as previously-untold stories from Kompalla himself. Although Kompalla’s role in the Summit Series has been largely omitted or obfuscated for the past half century, The September He Remembers is finally the first step in correcting a major historical oversight and adding a new chapter in the Summit Series’ growing legacy.
    • Rethinking the university: a case study

      Davis, Alan R.; Jhangiani, Rajiv; Purvey, Diane (Emerald, 2022-12-19)
      Purpose This study aims to describe and illuminate the ways in which Kwantlen Polytechnic University (KPU) – an urban, undergraduate institution with a strong focus on teaching, learning and related research and scholarship, and a substantial international student population – adapted to pandemic conditions in 2020 in an effort to meet community and pedagogical priorities, institutional/legal responsibilities and strategic goals. Design/methodology/approach Three institutional leaders at KPU draw together their respective insights and experiences, reflecting on how governance, pedagogy and operations were impacted by COVID-19. Findings After two years of continuous operation during the COVID-19 pandemic, and with the strong support of its learners and the faculty, KPU has undergone significant pedagogical and technological shifts to become a multi-modal university for study, teaching and administration. Research limitations/implications This is a “practitioner paper” with a practical focus on institutional leadership and adaptation in a period of rapid adjustment. It is more of an accounting and reflection piece than a critical analysis. Practical implications It offers post-secondary leaders’ insights into ways in which institutional values and community needs inform policy-making, operations and innovation in education. Social implications KPU’s domestic and international student constituencies are complex and required unconventional post-secondary strategies regarding faculty autonomy and growth, de-colonization and inclusion. Originality/value KPU has a distinctive mandate in British Columbia and its commitment to experiential learning – typically associated with hands-on education – presented unusual challenges for delivery. While research-and-teaching universities were tested by COVID-19, their tests were largely alike. KPU’s experience illustrates what practical- and teaching-focused institutions confronted.
    • On a Summer Trip

      Knight, Derek; Parayre, Catherine; Serfas, Shawn (2022-12-19)
      Someone dies. Three friends meet; one travels from the West, another comes back to Canada, the third one welcomes them in his garden.
    • Relationships between sales of legal medical cannabis and alcohol in Canada

      Armstrong, Michael J. (Elsevier BV, 2022-11)
      The extent to which legalizing cannabis use might lead to increased or decreased alcohol use has important implications for public health, economic growth, and government policy. This study analyzed Canada’s monthly per capita sales of alcohol and legal medical cannabis using fixed effect panel data linear regressions. The data covered seven Canadian regions from January 2011 to September 2018, and controlled for changing levels of retail activity, alcohol prices, tertiary education, unemployment, and impaired driving penalties. The analysis estimated that each dollar of legal medical cannabis sold was associated with an average alcohol sales decrease of roughly $0.74 to $0.84. This suggests that medical cannabis was an economic substitute for alcohol in Canada, and that the country’s 2017-2018 alcohol sales were roughly 1.8% lower than they would have been without legal medical cannabis. The results therefore indirectly imply that reduced alcohol consumption might have partly offset cannabis legalization’s health and economic impacts.
    • Culture of Cancer Cells at Physiological Oxygen Levels Affects Gene Expression in a Cell-Type Specific Manner

      Alva, Ricardo; Moradi, Fereshteh; Liang, Ping; Stuart, Jeffrey A. (MDPI, 2022)
      Standard cell culture is routinely performed at supraphysiological oxygen levels (~18% O2). Conversely, O2 levels in most mammalian tissues range from 1–6% (physioxia). Such hyperoxic conditions in cell culture can alter reactive oxygen species (ROS) production, metabolism, mitochondrial networks, and response to drugs and hormones. The aim of this study was to investigate the transcriptional response to different O2 levels and determine whether it is similar across cell lines, or cell line-specific. Using RNA-seq, we performed differential gene expression and functional enrichment analyses in four human cancer cell lines, LNCaP, Huh-7, PC-3, and SH-SY5Y cultured at either 5% or 18% O2 for 14 days. We found that O2 levels affected transcript abundance of thousands of genes, with the affected genes having little overlap between cell lines. Functional enrichment analysis also revealed different processes and pathways being affected by O2 in each cell line. Interestingly, most of the top differentially expressed genes are involved in cancer biology, which highlights the importance of O2 levels in cancer cell research. Further, we observed several hypoxia-inducible factor (HIF) targets, HIF-2α targets particularly, upregulated at 5% O2, consistent with a role for HIFs in physioxia. O2 levels also differentially induced the transcription of mitochondria-encoded genes in most cell lines. Finally, by comparing our transcriptomic data from LNCaP and PC-3 with datasets from the Prostate Cancer Transcriptome Atlas, a correlation between genes upregulated at 5% O2 in LNCaP cells and the in vivo prostate cancer transcriptome was found. We conclude that the transcriptional response to O2 over the range from 5–18% is robust and highly cell-type specific. This latter finding indicates that the effects of O2 levels are difficult to predict and thus highlights the importance of regulating O2 in cell culture.