Now showing items 21-40 of 530

    • Development of a dual-factor measure of adolescent mental health: an analysis of cross-sectional data from the 2014 Canadian Health Behaviour in School-aged Children (HBSC) study

      King, Nathan; Davison, Colleen M; Pickett, William (BMJ, 2021-09-30)
      Introduction Studies of adolescent mental health require valid measures that are supported by evidence-based theories. An established theory is the dual-factor model, which argues that mental health status is only fully understood by incorporating information on both subjective well-being and psychopathology. Objectives To develop a novel measure of adolescent mental health based on the dual-factor model and test its construct validity. Design Cross-sectional analysis of national health survey data. Setting and participants Nationally weighted sample of 21 993 grade 6–10 students; average age: 14.0 (SD 1.4) years from the 2014 Canadian Health Behaviour in School-aged Children study. Measures Self-report indicators of subjective well-being (life satisfaction, positive and negative affect), and psychopathology (psychological symptoms and overt risk-taking behaviour) were incorporated into the dual-factor measure. Characteristics of adolescents families, specific mental health indicators and measures of academic and social functioning were used in the assessment of construct validity. Results Proportions of students categorised to the four mental health groups indicated by the dual-factor measure were 67.6% ‘mentally healthy’, 17.5% ‘symptomatic yet content’, 5.5% ‘asymptomatic yet discontent’ and 9.4% ‘mentally unhealthy’. Being mentally healthy was associated with the highest functioning (greater social support and academic functioning) and being mentally unhealthy was associated with the worst. A one-unit increase (ranges=0–10) in peer support (OR 1.19; 95%CI 1.15 to 1.22), family support (OR 1.32; 95%CI 1.28 to 1.36), student support (OR 1.20; 95%CI 1.17 to 1.24) and average school marks (OR 1.18; 95%CI 1.10 to 1.27) increased the odds of being symptomatic yet content versus mentally unhealthy. Mentally healthy youth were the most likely to live with both parents (77% vs ≤65%) and report their family as well-off (62% vs ≤53%). Conclusions We developed a novel, construct valid dual-factor measure of adolescent mental health. This potentially provides a nuanced and comprehensive approach to the assessment of adolescent mental health that is direly needed.
    • Serum MMP‐3 and its association with central arterial stiffness among young adults is moderated by smoking and BMI

      Iannarelli, Nathaniel J.; MacNeil, Adam J.; Dempster, Kylie S.; Wade, Terrance J.; O’Leary, Deborah D. (Wiley, 2021-06-10)
      Central arterial stiffness is an independent predictor of cardiovascular disease. It is characterized by a marked reduction in the elastin-collagen ratio of the arterial wall extracellular matrix (ECM), and is largely the result of degradation of various ECM components. Matrix metalloproteinase-3 (MMP-3) may contribute to central arterial stiffness via its involvement in ECM homeostasis and remodeling. This study examined the association between serum MMP-3 concentrations and central arterial stiffness and potential interactions of MMP-3 and traditional cardiovascular risk factors in a population of healthy young adults. A total of 206 participants (n = 109 females) aged 19–25 years were included in the current study. Central arterial stiffness was measured non-invasively as carotid-femoral pulse wave velocity (cfPWV) (m/s). MMP-3 concentrations (ng/ml) were measured using ELISA techniques. Regression analyses were used to examine the association between cfPWV and MMP-3, adjusting for age, sex, smoking status, body mass index (BMI), instantaneous mean arterial pressure (MAP) and heart rate, and serum C-reactive protein. Interactions between MMP-3 with smoking, BMI, sex, and MAP were analyzed in subsequent regression models. MMP-3 was an independent predictor of cfPWV (β = 0.187, p = 0.007), and significant interactions between MMP-3 and regular smoking (β = 0.291, p = 0.022), and MMP-3 and BMI (β = 0.210, p = 0.013) were observed. Higher serum MMP-3 concentrations were associated with a faster cfPWV and thus, greater central arterial stiffness. Interactions between MMP-3 and smoking, and MMP-3 and BMI may, in part, drive the association between MMP-3 and central arterial stiffness.
    • Characterization of Alzheimer's disease‐like neuropathology in Duchenne's muscular dystrophy using the DBA/2J mdx mouse model

      Hayward, Grant C.; Caceres, Daniela; Copeland, Emily N.; Baranowski, Bradley J.; Mohammad, Ahmad; Whitley, Kennedy C.; Fajardo, Val A.; MacPherson, Rebecca E. K. (Wiley, 2021-11-11)
      Duchenne muscular dystrophy (DMD) is a progressive muscle wasting disorder caused by a mutation in the dystrophin gene. In addition to muscle pathology, some patients with DMD will exhibit cognitive impairments with severity being linked to age and type of genetic mutation. Likewise, some studies have shown that mdx mice display impairments in spatial memory compared with wild-type (WT) controls, while others have not observed any such effect. Most studies have utilized the traditional C57BL/10 (C57) mdx mouse, which exhibits a mild disease phenotype. Recently, the DBA/2J (D2) mdx mouse has emerged as a more severe and perhaps clinically relevant DMD model; however, studies examining cognitive function in these mice are limited. Thus, in this study we examined cognitive function in age-matched C57 and D2 mdx mice along with their respective WT controls. Our findings show that 8- to 12-week-old C57 mdx mice did not display any differences in exploration time when challenged with a novel object recognition test. Conversely, age-matched D2 mdx mice spent less time exploring objects in total as a well as less time exploring the novel object, suggestive of impaired recognition memory. Biochemical analyses of the D2 mdx brain revealed higher soluble amyloid precursor protein b(APPb) and APP in the prefrontal cortex of mdx mice compared with WT, and lower soluble APPa in the hippocampus, suggestive of a shift towards amyloidogenesis and a similar pathogenesis to Alzheimer’s disease. Furthermore, our study demonstrates the utility of the D2 mdx model in studying cognitive impairment.
    • Ecosystem-Based Adaptation to Protect Avian Species in Coastal Communities in the Greater Niagara Region, Canada

      Gauthier, Samantha; May, Bradley; Vasseur, Liette (MDPI AG, 2021-06-04)
      Coastal communities are increasingly vulnerable to climate change and its effects may push coastal ecosystems to undergo irreversible changes. This is especially true for shorebirds with the loss of biodiversity and resource-rich habitats to rest, refuel, and breed. To protect these species, it is critical to conduct research related to nature-based Solutions (NbS). Through a scoping review of scientific literature, this paper initially identified 85 articles with various ecosystem-based adaptation (EbA) strategies that could help conserve shorebird populations and promote ecotourism. Of these 85 articles, 28 articles had EbA strategies that were examined, with some like coral reefs and mangroves eliminated as they were inappropriate for this region. The scoping review identified four major EbA strategies for the Greater Niagara Region with living shorelines and beach nourishment being the most suitable, especially when combined. These strategies were then evaluated against the eight core principles of nature-based solutions protecting shorebird as well as human wellbeing. Living shoreline strategy was the only one that met all eight NbS principles. As the coastline of the region greatly varies in substrate and development, further research will be needed to decide which EbA strategies would be appropriate for each specific area to ensure their efficacy.
    • Sleep problems among sexual minorities: a longitudinal study on the influence of the family of origin and chosen family

      Chum, Antony; Nielsen, Andrew; Teo, Celine (Springer Science and Business Media LLC, 2021-12-21)
      Background: There is growing evidence that lesbian, gay, and bisexual (LGB) adults experience more sleep problems than the general population. As LGB individuals experience a signifcantly greater risk of family rejection and low family support, our study investigates the role of family support as a potential determinant of LGB sleep problems over a prolonged period, and whether friend support (i.e. chosen family) can mitigate the efect of low family support. Given the importance of sleep on mental and physical health, study results may help shed light on persistent health disparities across sexual orientations. Methods: Our sample included 1703 LGB individuals from the UK Household Longitudinal Study (UKHLS). Mixed-efect logistic regressions were used to estimate the efect of family and friend support on the development of sleep problems after 24months while controlling for potential confounders. A modifed Pittsburgh Sleep Quality Index was used to measure 1) presence of any sleep problems, 2) short sleep duration, and 3) poor sleep quality. Results: Family support at baseline was independently associated with all sleep problems in our study after 24-months: 1 SD increase in family support was associated with a 0.94 times lower risk of sleep problems (95% C.I=0.90-0.98), a 0.88 times lower risk of short sleep duration (95% C.I=0.81-0.95), and a 0.92 times lower risk of sleep quality (95% C.I=0.93-0.98). Support from one’s chosen family (proxied by friend support) did not mitigate the efects of low family support on sleep problems. Conclusions: Our study found a consistent efect of family support across all sleep outcomes along with evidence of a persistent efect after 24months. Our fndings point to the importance of targeting family support in designing interventions aimed at reducing LGB sleep problems.
    • When the Easy Becomes Difficult: Factors Affecting the Acquisition of the English /iː/-/ɪ/ Contrast

      Cebrian, Juli; Gorba, Celia; Gavaldà, Núria (Frontiers Media SA, 2021-06-10)
      The degree of similarity between the sounds of a speaker’s first and second language (L1 and L2) is believed to determine the likelihood of accurate perception and production of the L2 sounds. This paper explores the relationship between cross-linguistic similarity and the perception and production of a subset of English vowels, including the highly productive /iː/-/ɪ/ contrast (as in “beat” vs. “bit”), by a group of Spanish/Catalan native speakers learning English as an L2. The learners’ ability to identify, discriminate and produce the English vowels accurately was contrasted with their cross-linguistic perceived similarity judgements. The results showed that L2 perception and production accuracy was not always predicted from patterns of cross-language similarity, particularly regarding the difficulty distinguishing /iː/ and /ɪ/. Possible explanations may involve the way the L2 /iː/ and /ɪ/ categories interact, the effect of non-native acoustic cue reliance, and the roles of orthography and language instruction.
    • Characterizing SERCA Function in Murine Skeletal Muscles after 35–37 Days of Spaceflight

      Braun, Jessica L.; Geromella, Mia S.; Hamstra, Sophie I.; Messner, Holt N.; Fajardo, Val A. (MDPI AG, 2021-10-29)
      It is well established that microgravity exposure causes significant muscle weakness and atrophy via muscle unloading. On Earth, muscle unloading leads to a disproportionate loss in muscle force and size with the loss in muscle force occurring at a faster rate. Although the exact mechanisms are unknown, a role for Ca2+ dysregulation has been suggested. The sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) pump actively brings cytosolic Ca2+ into the SR, eliciting muscle relaxation and maintaining low intracellular Ca2+ ([Ca2+]i). SERCA dysfunction contributes to elevations in [Ca2+]i, leading to cellular damage, and may contribute to the muscle weakness and atrophy observed with spaceflight. Here, we investigated SERCA function, SERCA regulatory protein content, and reactive oxygen/nitrogen species (RONS) protein adduction in murine skeletal muscle after 35–37 days of spaceflight. In male and female soleus muscles, spaceflight led to drastic impairments in Ca2+ uptake despite significant increases in SERCA1a protein content. We attribute this impairment to an increase in RONS production and elevated total protein tyrosine (T) nitration and cysteine (S) nitrosylation. Contrarily, in the tibialis anterior (TA), we observed an enhancement in Ca2+ uptake, which we attribute to a shift towards a faster muscle fiber type (i.e., increased myosin heavy chain IIb and SERCA1a) without elevated total protein T-nitration and S-nitrosylation. Thus, spaceflight affects SERCA function differently between the soleus and TA.
    • Exploring the Effects of Greek Yogurt Supplementation and Exercise Training on Serum Lithium and Its Relationship With Musculoskeletal Outcomes in Men

      Baranowski, Ryan W.; Skelly, Lauren E.; Josse, Andrea R.; Fajardo, Val A. (Frontiers Media SA, 2021-12-22)
      Dairy products can act as a dietary source of lithium (Li), and a recent study in university-aged males demonstrated that Greek yogurt (GY) supplementation augmented gains in fat free mass, strength and bone formation after 12 weeks of resistance exercise training compared to carbohydrate (CHO) pudding supplementation. Here, we performed secondary analyses to explore whether GY would alter serum Li levels and whether changes in serum Li would associate with changes in body composition, strength, and bone turnover markers. Results show that the GY group maintained serum Li levels after exercise training, whereas the CHO group did not. Maintaining/elevating serum Li levels was also associated with greater gains in strength and reductions in bone resorption. However, controlling for other dietary factors in GY such as protein and calcium weakened these associations. Thus, future studies should assess the causative role, if any, of dietary Li alone on strength and bone resorption in humans.
    • Examination of BDNF Treatment on BACE1 Activity and Acute Exercise on Brain BDNF Signaling

      Baranowski, Bradley J.; Hayward, Grant C.; Marko, Daniel M.; MacPherson, Rebecca E. K. (Frontiers Media SA, 2021-05-04)
      Perturbations in metabolism results in the accumulation of beta-amyloid peptides, which is a pathological feature of Alzheimer’s disease. Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) is the rate limiting enzyme responsible for beta-amyloid production. Obesogenic diets increase BACE1 while exercise reduces BACE1 activity, although the mechanisms are unknown. Brain-derived neurotropic factor (BDNF) is an exercise inducible neurotrophic factor, however, it is unknown if BDNF is related to the effects of exercise on BACE1. The purpose of this study was to determine the direct effect of BDNF on BACE1 activity and to examine neuronal pathways induced by exercise. C57BL/6J male mice were assigned to either a low (n = 36) or high fat diet (n = 36) for 10 weeks. To determine the direct effect of BDNF on BACE1, a subset of mice (low fat diet = 12 and high fat diet n = 12) were used for an explant experiment where the brain tissue was directly treated with BDNF (100 ng/ml) for 30 min. To examine neuronal pathways activated with exercise, mice remained sedentary (n = 12) or underwent an acute bout of treadmill running at 15 m/min with a 5% incline for 120 min (n = 12). The prefrontal cortex and hippocampus were collected 2-h post-exercise. Direct treatment with BDNF resulted in reductions in BACE1 activity in the prefrontal cortex (p < 0.05), but not the hippocampus. The high fat diet reduced BDNF content in the hippocampus; however, the acute bout of exercise increased BDNF in the prefrontal cortex (p < 0.05). These novel findings demonstrate the region specific differences in exercise induced BDNF in lean and obese mice and show that BDNF can reduce BACE1 activity, independent of other exercise-induced alterations. This work demonstrates a previously unknown link between BDNF and BACE1 regulation.
    • Co-Optimizing Battery Storage for Energy Arbitrage and Frequency Regulation in Real-Time Markets Using Deep Reinforcement Learning

      Miao, Yushen; Chen, Tianyi; Bu, Shengrong; Liang, Hao; Han, Zhu (MDPI, 2021)
      Battery energy storage systems (BESSs) play a critical role in eliminating uncertainties associated with renewable energy generation, to maintain stability and improve flexibility of power networks. In this paper, a BESS is used to provide energy arbitrage (EA) and frequency regulation (FR) services simultaneously to maximize its total revenue within the physical constraints. The EA and FR actions are taken at different timescales. The multitimescale problem is formulated as two nested Markov decision process (MDP) submodels. The problem is a complex decision-making problem with enormous high-dimensional data and uncertainty (e.g., the price of the electricity). Therefore, a novel co-optimization scheme is proposed to handle the multitimescale problem, and also coordinate EA and FR services. A triplet deep deterministic policy gradient with exploration noise decay (TDD-ND) approach is used to obtain the optimal policy at each timescale. Simulations are conducted with real-time electricity prices and regulation signals data from the American PJM regulation market. The simulation results show that the proposed approach performs better than other studied policies in literature.
    • Ephemeral Heritage: Boats, Migration, and the Central Mediterranean Passage

      Greene, Elizabeth S.; Leidwanger, Justin; Repola, Leopoldo (The University of Chicago Press, 2022)
      The central Mediterranean today marks one of the most active and dangerous routes for sea crossings to Europe, due in no small part to border regimes designed to prevent the mobilities that have defined these waters from earliest antiquity. This article considers initial results of fieldwork undertaken to document and make visible the material culture of contemporary vessels used to carry forced and undocumented migrants to southeast Sicily over the past decade. These former fishing craft reveal structural and spatial adaptations to facilitate a different traffic, reflected also in items left behind when the boats were intercepted. Archaeology helps to embed these journeys within long-term frameworks of connectivity and to situate their ephemeral traces alongside more traditional notions of Mediterranean maritime heritage. In a region that celebrates its deep connections to the sea, care for the materiality of these contemporary mobilities foregrounds human experiences, while serving goals of advocacy, empowerment, and social justice amid global change.
    • Information Seeking Behaviors, Attitudes, and Choices of Academic Chemists

      Taylor & Francis, 2018-04-09
      Chemists in academic institutions utilize a variety of resources and strategies to remain current and to track scholarly information, patents, and news. To explore how chemists in academic institutions remain current, librarians at four Canadian university institutions surveyed 231 and interviewed 14 chemistry faculty, staff, and graduate students on their information seeking behaviors and attitudes. According to survey results, a minority of chemists (13.9 percent) acknowledged that they were successfully keeping up to date, while 50.6 percent indicated that they were somewhat successful. However, a significant number of chemists (35.5 percent) indicated that they were unsuccessful and could do better in remaining current with information. Investigators analyzing focus group data identified three emergent themes related to remaining current: (1) there is “too much information – and not enough time.” No single information seeking strategy works; (2) “patents are important – but messy.” Chemists find themselves largely suspicious about the value and credibility of patents; and (3) chemists “could do better” in keeping up to date with new and emerging technologies. Chemists continue to be open to new tools and resources yet readily acknowledge that they are too often not sure which information seeking behaviors, resources, or strategies work best. This study helps to shed light on opportunities to identify and meet chemists’ evolving information needs.
    • Information Seeking Behaviors, Attitudes, and Choices of Academic Mathematicians

      Taylor & Francis, 2020-06-05
      Mathematicians in academic institutions utilize a variety of resources and strategies to seek, find, and use scholarly information and news. Using a sample of mathematicians, researchers surveyed 112 students and faculty at four Canadian university institutions to explore self-perceived success rates, resources consulted, databases used, use of social media, and citation management systems. Further, 12 follow-up interviews were completed with mathematicians to better interpret survey results, resulting information-seeking behaviors, choices, strategies, and feelings on keeping up to date with information needs. According to survey results, a minority of mathematicians (12.5 percent) acknowledged that they were successfully keeping up to date. However, a significant number of mathematicians (28.6 percent) indicated that they were unsuccessful and could do better in remaining current with information needs. Co-investigators, using qualitative analyses, identified four emergent themes related to remaining current: (1) The “slower pace of math” pervades all aspects of this discipline;” (2) There are “too many papers – and not enough time” to effectively search, evaluate, and read scholarly papers of interest; (3) Mathematicians collectively acknowledge that they are open to strategies and technologies where they “could do better” keeping up to date; and (4) Mathematicians have divided loyalties using databases when searching for information by means of “MathSciNet in a Google world.” Additional insights document how mathematicians are guided by mathematical peculiarities and discipline-specific practices. This study helps to shed light on opportunities for academic librarians to identify and meet mathematicians’ evolving information needs.
    • Information Seeking Behaviors, Attitudes, and Choices of Academic Physicists

      Taylor & Francis, 2022-01-10
      Physicists in academic institutions utilize a variety of resources and strategies to seek, find, and use scholarly information and news. Using a sample of physicists, researchers surveyed 182 students and faculty at seven Canadian university institutions to explore self-perceived success rates, resources consulted, databases used, and use of social media and citation management systems. To complement the survey, 11 follow up interviews/focus groups were completed with participants to further uncover information-seeking behaviors, choices, strategies, and feelings around keeping up to date with information needs. According to survey results, a minority of physicists (15.4%) acknowledged that they were successfully keeping up to date. However, a significant number of physicists (28.6%) indicated that they were unsuccessful and could do better in remaining current with information needs. Co-investigators, using qualitative analyses, identified four emergent themes: (1) There are “too many papers – and not enough time” to effectively search, evaluate and read scholarly papers of interest; (2) Staying up to date is important especially in competitive research areas; (3) Graduate students seek information differently than faculty and experienced researchers; and (4) The arXiv database is important to many physicists. Additional minor themes included physics-related publishing is constantly evolving; physicists use a variety of information-seeking behaviors; and, information-seeking methods can differ between physics subdisciplines. This study aims to shed light on opportunities for academic librarians to identify and meet physicists’ evolving information behaviors, attitudes, choices, and needs.
    • Engaging with Digital Texts/Images in Literatures and the Arts

      Colella, Carmela; El-Hoss, Tamara; Parayre, Catherine (small walker press, 2021)
      Les nouveaux outils numériques continuent de transformer la pensée des artistes et auteur.es, ainsi que leur façon de s’engager dans la création. Au cours des dernières décennies, les avancées technologiques ont permis de concevoir et de développer de nouvelles pratiques en littérature et dans les arts, avec pour résultat d’innombrables créations innovantes. Les outils numériques rendent possible un meilleur accès aux textes littéraires et facilitent des interactions complexes entre la littérature et les autres arts. De même, les arts visuels et autres ont conçu de nouvelles intégrations du texte dans leurs réalisations. Ces nouvelles pratiques ont changé notre discours visuel et textuel. New digital tools continue to transform the way artists and writers think about, engage with, and create works. In the last decades, advances in technology have facilitated the design and writing process, allowing the creation of countless virtual renditions of concepts or works. Digital tools have impacted the traditional literary world, opening access to a variety of digitized texts and enabling increased interactions with other art forms. In turn, visual and other creative arts have conceived new integrations of text within their medium, all of which has impacted and changed our visual and written discourse.
    • Did the UK COVID-19 Lockdown Modify the Influence of Neighbourhood Disorder on Psychological Distress? Evidence From a Prospective Cohort Study

      Teo, Celine; Kim, Chungah; Nielsen, Andrew; Young, Thomas; O'Campo, Patricia; Chum, Antony (Frontiers Media, 2021)
      National lockdown in the UK during the COVID-19 pandemic severely restricted the mobility of residents and increased time spent in their residential neighbourhoods. This is a unique opportunity to understand how an exogenous factor that reduces mobility may influence the association between neighbourhood social environment and mental health. This study investigates whether the COVID-19 lockdown may modify the effect of neighbourhood disorder on psychological distress. Methods: We tracked changes in psychological distress, using the UK household longitudinal survey across the pre-COVID and lockdown periods in 16,535 adults. Neighbourhood disorder was measured along two subscales: social stressors and property crime. Fixed-effects regression was used to evaluate whether the widespread reduction in mobility modifies the association between the subscales of neighbourhood disorder and psychological distress. Results: The effect of neighbourhood social stressors on psychological distress was stronger in the lockdown period compared to the pre-COVID period. Compared to the pre-COVID period, the effect of being in neighbourhoods with the highest social stressors (compared to the lowest) on psychological distress increased by 20% during the lockdown. Meanwhile, the effect of neighbourhood property crime on mental health did not change during the lockdown. Conclusion: The sudden loss of mobility as a result of COVID-19 lockdown is a unique opportunity to address the endogeneity problem as it relates to mobility and locational preferences in the study of neighbourhood effects on health. Vulnerable groups who have limited mobility are likely more sensitive to neighbourhood social stressors compared to the general population.
    • Team Dynamics and Learning Opportunities in Social Science Research Teams

      McGinn, Michelle K.; Niemczyk, Ewelina K. (University of Alberta. Faculty of Education., 2020)
      Although the contemporary research environment encourages knowledge generation through research collaboration rather than individualized projects, limited scholarly attention has been devoted to the practice of collaboration within research teams. This paper presents a qualitative analysis of team dynamics and learning opportunities within four social science research teams. The findings reveal similarities and differences in leadership style and interaction approaches that affected how research was undertaken and the possibilities for team members to learn from each other. The snapshots provide models for other research teams that extend situated learning theories and the existing research base about collaboration, research teams, and research leadership.
    • Peer-to-Peer Energy Trading and Energy Conversion in Interconnected Multi-Energy Microgrids Using Multi-Agent Deep Reinforcement Learning

      Chen, Tianyi; Bu, Shengrong; Liu, Xue; Kang, Jikun; Yu, F. Richard; Han, Zhu (Institute of Electrical and Electronics Engineers (IEEE), 2021)
      A key aspect of multi-energy microgrids (MEMGs) is the capability to efficiently convert and store energy in order to reduce the costs and environmental impact. Peer-to-peer (P2P) energy trading is a novel paradigm for decentralized energy market designs. In this paper, we investigate the external P2P energy trading problem and internal energy conversion problem within interconnected residential, commercial and industrial MEMGs. These two problems are complex decision-making problems with enormous high-dimensional data and uncertainty, so a multi-agent deep reinforcement learning approach combining the multi-agent actor-critic algorithm with the twin delayed deep deterministic policy gradient algorithm is proposed. The proposed approach can handle the high-dimensional continuous action space and aligns with the nature of P2P energy trading with multiple MEMGs. Simulation results based on three real-world MG datasets show that the proposed approach significantly reduces each MG's average hourly operation cost. The impact of carbon tax pricing is also considered.
    • The Transition Online: A Mixed-Methods Study of the Impact of COVID-19 on Students with Disabilities in Higher Education

      Mullins, Laura E; Mitchell, Jennifer (Sciedu Press, 2021-09-05)
      Following the World Health Organization’s announcement of the global pandemic because of the Coronavirus Disease 2019, most Canadian universities transitioned to offering their courses exclusively online. One group affected by this transition was students with disabilities. Previous research has shown that the university experience for students with disabilities differs from those of their non-disabled peers. However, their unique needs are often not taken into consideration. As a result, students can become marginalized and alienated from the online classroom. In partnership with Student Accessibility Services, this research revealed the impact of the transition to online learning because of the pandemic for university students with disabilities. Students registered with Student Accessibility Services completed a survey about the effects of online learning during a pandemic on the students’ lives, education, and instructional and accommodation. It was clear from the results that online education during COVID-19 affected all aspects of the students’ lives, particularly to their mental health. This research provided a much-needed opportunity for students with disabilities to share the factors influencing their educational experience and identified recommendations instructors should consider when developing online courses to increase accessibility and improve engagement.
    • The role of the arousal system in age‐related differences in cortical functional network architecture

      Guardia, Tiago; Geerligs, Linda; Tsvetanov, Kamen A.; Ye, Rong; Campbell, Karen L. (Wiley, 2021-10-29)
      A common finding in the aging literature is that of the brain's decreased within- and increased between-network functional connectivity. However, it remains unclear what is causing this shift in network organization with age. Given the essential role of the ascending arousal system (ARAS) in cortical activation and previous findings of disrupted ARAS functioning with age, it is possible that age differences in ARAS func- tioning contribute to disrupted cortical connectivity. We test this possibility here using resting state fMRI data from over 500 individuals across the lifespan from the Cambridge Center for Aging and Neuroscience (Cam-CAN) population-based cohort. Our results show that ARAS-cortical connectivity declines with age and, consistent with our expectations, significantly mediates some age-related differences in connec- tivity within and between association networks (specifically, within the default mode and between the default mode and salience networks). Additionally, connectivity between the ARAS and association networks predicted cognitive performance across several tasks over and above the effects of age and connectivity within the cortical networks themselves. These findings suggest that age differences in cortical connec- tivity may be driven, at least in part, by altered arousal signals from the brainstem and that ARAS–cortical connectivity relates to cognitive performance with age.