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Recent Submissions

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Open Access
Predicting the Movement of Occluded Objects Using Motion Models and Statistical Tracking
(2024-03-14) Grond, Marco Marten; Boyd, Jeffrey Edwin; Alim, Usman; Denzinger, Jörg; Yanushkevich, Svetlana; Laganière, Robert
Long-term occlusions pose a significant challenge to tracking systems, resulting in broken tracks which obfuscate results and lead to ambiguity when analysing a scene. My proposed solution to this problem, which I call the Occluded Trajectory Modelling (OTM) system, predicts the movement of occluded objects with a statistically-learned model of their movements while occluded, allowing for seamless tracking across occlusions. The model detailing the movement of occluded objects is extracted from unannotated data using Network Tomography and an objective function which extracts object occlusion times. I create a hybrid system, consisting of the OTM working in conjunction with an adapted Multiple Hypothesis Tracker, that is able to seamlessly transition between tracking visible objects and predicting their movement while they are occluded. This is done in real time without the need for visual features. I test my system on two datasets: the first consisting of drone footage with multiple environmental occlusions, and the second containing scenes with multiple non-overlapping cameras. The experimental results obtained from both of these datasets show that my system outperforms existing visual tracking systems in terms of correctly re-identifying objects after occlusion, without suffering a performance trade-off.
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Open Access
R2DRV: study protocol for longitudinal assessment of driving after mild TBI in young drivers
(2024-03-13) Yang, Jingzhen; Stavrinos, Despina; Kerwin, Thomas; Mrug, Sylvie; Tiso, Michael; McManus, Benjamin; Wrabel, Cameron G.; Rundus, Christopher; Zhang, Fangda; Davis, Drew; Swanson, Erin M.; Bentley, Brett; Yeates, Keith O.
Abstract Background Mild traumatic brain injury (mTBI) and traffic-related injuries are two major public health problems disproportionately affecting young people. Young drivers, whose driving skills are still developing, are particularly vulnerable to impaired driving due to brain injuries. Despite this, there is a paucity of research on how mTBI impacts driving and when it is safe to return to drive after an mTBI. This paper describes the protocol of the study, R2DRV, Longitudinal Assessment of Driving After Mild TBI in Young Drivers, which examines the trajectory of simulated driving performance and self-reported driving behaviors from acutely post-injury to symptom resolution among young drivers with mTBI compared to matched healthy drivers. Additionally, this study investigates the associations of acute post-injury neurocognitive function and cognitive load with driving among young drivers with and without mTBI. Methods A total of 200 young drivers (ages 16 to 24) are enrolled from two study sites, including 100 (50 per site) with a physician-confirmed isolated mTBI, along with 100 (50 per site) healthy drivers without a history of TBI matched 1:1 for age, sex, driving experience, and athlete status. The study assesses primary driving outcomes using two approaches: (1) high-fidelity driving simulators to evaluate driving performance across four experimental study conditions at multiple time points (within 96 h of injury and weekly until symptom resolution or 8 weeks post-injury); (2) daily self-report surveys on real-world driving behaviors completed by all participants. Discussion This study will fill critical knowledge gaps by longitudinally assessing driving performance and behaviors in young drivers with mTBI, as compared to matched healthy drivers, from acutely post-injury to symptom resolution. The research strategy enables evaluating how increased cognitive load may exacerbate the effects of mTBI on driving, and how post-mTBI neurocognitive deficits may impact the driving ability of young drivers. Findings will be shared through scientific conferences, peer-reviewed journals, and media outreach to care providers and the public.
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Open Access
Correction: Swarm Thermal Ion Imager measurement performance
(2024-03-11) Burchill, Johnathan K.; Knudsen, David J.
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Open Access
An exploration of COVID-19 vaccination models for newcomer refugees and immigrants in Calgary, Canada
(2024-03-12) Aghajafari, Fariba; Wall, Laurent; Weightman, Amanda M.; Ness, Alyssa; Lake, Deidre; Anupindi, Krishna; Moorthi, Gayatri; Kuk, Bryan; Santana, Maria; Coakley, Annalee
Abstract Background The World Health Organization stresses the need for tailored COVID-19 models of vaccination to meet the needs of diverse populations and ultimately reach high rates of vaccination. However, little evidence exists on how COVID-19 models of vaccination operated in the novel context of the pandemic, how vulnerable populations, such as refugees, experience COVID-19 vaccination systems in high-income countries, and what lessons may be learned from vaccination efforts with vulnerable populations. To address this gap, this study explored COVID-19 vaccine delivery models available to newcomer refugees and immigrants, and refugee experiences across different COVID-19 vaccine delivery models in Calgary, Canada, and surrounding area in 2021 and 2022, to understand the barriers, strengths, and strategies of models to support access to COVID-19 vaccination for newcomer refugees and immigrants. Methods Researchers conducted structured interviews with Government Assisted Refugees (n = 39), and semi-structured interviews with Privately Sponsored Refugees (n = 6), private refugee sponsors (n = 3), and stakeholders involved in vaccination systems (n = 13) in 2022. Thematic analysis was conducted to draw out themes related to barriers, strengths, and strategies of vaccine delivery models and the intersections with patient experiences. Results Newcomer refugee and immigrant focused vaccination models and strategies were explored. They demonstrated how partnerships between organizations, multi-pronged approaches, and culturally responsive services were crucial to navigate ongoing and emergent factors, such as vaccine hesitancy, mandates, and other determinants of under-vaccination. Many vaccination models presented through interviews were not specific to refugees and included immigrants, temporary residents, ethnocultural community members, and other vulnerable populations in their design. Conclusions Increasing COVID-19 vaccine uptake for newcomer refugees and immigrants, is complex and requires trust, ongoing information provision, and local partnerships to address ongoing and emerging factors. Three key policy implications were drawn. First, findings demonstrated the need for flexible funding to offer outreach, translation, cultural interpretation, and to meet the basic needs of patients prior to engaging in vaccinations. Second, the research showed that embedding culturally responsive strategies within services ensures community needs are met. Finally, collaborating with partners that reflect the diverse needs of communities is crucial for the success of any health efforts serving newcomers.
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Open Access
Prognostic value of near-infrared spectroscopy regional oxygen saturation and cerebrovascular reactivity index in acute traumatic neural injury: a CAnadian High-Resolution Traumatic Brain Injury (CAHR-TBI) Cohort Study
(2024-03-14) Gomez, Alwyn; Froese, Logan; Griesdale, Donald; Thelin, Eric P.; Raj, Rahul; van Iperenburg, Levi; Tas, Jeanette; Aries, Marcel; Stein, Kevin Y.; Gallagher, Clare; Bernard, Francis; Kramer, Andreas H.; Zeiler, Frederick A.
Abstract Background Near-infrared spectroscopy regional cerebral oxygen saturation (rSO2) has gained interest as a raw parameter and as a basis for measuring cerebrovascular reactivity (CVR) due to its noninvasive nature and high spatial resolution. However, the prognostic utility of these parameters has not yet been determined. This study aimed to identify threshold values of rSO2 and rSO2-based CVR at which outcomes worsened following traumatic brain injury (TBI). Methods A retrospective multi-institutional cohort study was performed. The cohort included TBI patients treated in four adult intensive care units (ICU). The cerebral oxygen indices, COx (using rSO2 and cerebral perfusion pressure) as well as COx_a (using rSO2 and arterial blood pressure) were calculated for each patient. Grand mean thresholds along with exposure-based thresholds were determined utilizing sequential chi-squared analysis and univariate logistic regression, respectively. Results In the cohort of 129 patients, there was no identifiable threshold for raw rSO2 at which outcomes were found to worsen. For both COx and COx_a, an optimal grand mean threshold value of 0.2 was identified for both survival and favorable outcomes, while percent time above − 0.05 was uniformly found to have the best discriminative value. Conclusions In this multi-institutional cohort study, raw rSO2was found to contain no significant prognostic information. However, rSO2-based indices of CVR, COx and COx_a, were found to have a uniform grand mean threshold of 0.2 and exposure-based threshold of − 0.05, above which clinical outcomes markedly worsened. This study lays the groundwork to transition to less invasive means of continuously measuring CVR.