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Modelling Low Dose Radiation Deposition using Wavelet-Based Texture Analysis
No full textRelating radiation energy deposition to cellular-level responses is key to understanding the biological impact of ionizing radiation. This work explores the distribution of cellular-scale energy deposition and response in irradiated radiochromic film. A challenge to analyzing radiochromic film at this resolution is the heterogeneities present in the films, which impact the film’s reaction to radiation and disrupt the spatial distribution of the radiation deposition. Wavelet transform is proposed as a method for removing the spatial impact of the film while maintaining the deposition’s spatial relationships. Further, principal component analysis is applied to the wavelet energy signatures to remove collinearity between the features before fitting a linear model to recover the original dose of radiation. This method is tested with microdosimetric Monte Carlo simulations, including the addition of two independent sources of film heterogeneity and then a combination of both, and experimental data from Raman spectroscopy
Optimization of Low-Temperature Solution-Processed Antimony Tin Oxide Thin-Film Field-Effect Transistor Fabrication Procedure for Neuromorphic Applications
No full textThis work focuses on optimizing the fabrication of solution-processed antimony tin oxide (ATO) nanoparticle film on 100 nm silicon oxide passivation layer by varying concentration, rotation speed, duration, and annealing temperature. A 550 nm ATO layer with nonlinear behaviour can be made consistently by forming a meniscus of dispersion over the wafer’s surface using 10%w/w ATO+H2O solution, spinning at 200 RPM for 30 minutes, and annealing at 250°C for 1 hour. Devices consist of ATO channel using the doped silicon substrate as a bottom gate, which show current enhancement without extinction, as altering the gate sweep voltage range results in a proportional translation or mirroring of the transfer function. Introducing measurement delays to the voltage sweeps have shown a major time-dependent component to the current in addition to some field-effect dependence. Application of sufficient gate voltage can cause a change in behaviour that could be evidence of valence-change memristor behaviour
Impact of the Early Life Stressors, Social Isolation and Food Restriction in an adolescent Female mouse model.
No full textMost studies investigating early life stress (ELS) have focused on the critical timepoint of infancy, few have examined the developmentally stress-sensitive adolescent period especially its effects on the female body. Examining the behavioural and biological underpinnings of sex differences in the development of neuropsychiatric and eating disorders such as depression, anxiety, anorexia, bulimia and binge-eating disorder is especially important given the higher prevalence and vulnerability in females. Signalling through the tropomyosin kinase B (TrkB) receptor and its cognate ligand, brain derived neurotrophic factor (BDNF) is known to play a role in both neuropsychiatric disorders and eating behaviours. In this study, we combined both social isolation and food deprivation in female mice during adolescence interested in developing a better understanding of how these stressors impact both behaviour and assessed biological outcomes in TrkB expression, which induced a binge-eating like behaviour, associated with alterations in TrkB isoform expression in the Insula
Dynamic Environmental Change at the Cusp of the Great Oxidation Event: The Gowganda-Lorrain Formation Transition, Cobalt Basin, Ontario and Quebec
No full textThe Huronian Supergroup, an early Paleoproterozoic (ca. 2.45-2.22 Ga) sedimentary succession preserved in Ontario and Quebec, catalogues evidence for the Great Oxidation Event (i.e., the initial rise of oxygen in the atmosphere) through the preservation of redox sensitive minerals in terrestrial deposits: (1) detrital pyrite and uraninite in older strata (evidence of an anoxic atmosphere), and (2) Earth’s earliest red, hematitic, sandstone in younger strata (indicative of a shift to an oxidizing atmosphere). This dissertation comprises three studies from the Cobalt Basin, a northern sub-basin of the greater Huron basin. The first two studies develop depositional models of the northern and easternmost portions of the Cobalt Basin providing details on the glacial to post-glacial paleoenvironments that preserve Earth’s earliest red sandstones. Stratigraphic measurements and correlations reveal that strata are preserved within paleovalleys, interpreted to have developed from glacial excavation as evidenced by basal subglacial deposits. Above these subglacial deposits, strata show a single progradational succession, which captures a transition from glaciomarine to warm and humid fluvial braidplain environments. At the flanks of the paleovalleys, alluvial and/or colluvial deposits occur indicating that terrestrial sedimentation was triggered by enhanced weathering in an unvegetated warm and humid setting due to topographic variations. The successions occur at proximal limits of a passive margin and indicate that progradation was influenced by relative sea-level fall linked to glacio-isostatic uplift. The third study investigates the petrogenesis of reddened sandstone of the aforementioned braidplain deposits. Petrography reveals single-grain rims of pigmentary hematite dust on detrital quartz that are encased by quartz overgrowth cement. This encapsulates evidence that reddening is a syn-sedimentary or early diagenetic feature, formed from widespread oxidizing meteoric waters in a terrestrial setting under an oxygenated atmosphere, prior to burial and lithification of the fluvial deposits. Reddening likely happened close to 2.31 Ga, providing an approximate age for the initiation of oxidative weathering in a terrestrial setting, triggering key feedbacks in nutrient cycling that possibly thrusted Earth’s atmosphere into a stable oxidizing state
The Role of Nature Cues and Nature Relatedness in Academic Motivation and Engagement
Get PDFNature exposure in the form of immersion in natural environments can benefit students in multiple ways. Across four studies, we examined whether nature exposure in the form of visual nature cues on instructional materials might increase academic motivation and engagement among university students. Visual nature cues were presented via PowerPoint backgrounds (Study 1), online Zoom lecture backgrounds (Study 2), and on the background of calendars people used to plan for an upcoming assignment or exam (Studies 3 and 4). In each study and an internal meta-analysis, we found no evidence that nature cues increased academic engagement or motivation compared to other background images. However, participants’ self-reported nature relatedness was linked to greater academic engagement and motivation in each study and the internal meta-analysis. The interaction between nature relatedness and nature exposure was not significant. We conclude that embedding visual nature cues in educational material is not sufficiently impactful to have an effect on academic motivation and that immersion and interaction with nature in a fuller sense may be necessary to reap motivational benefits
Adaptive Hierarchical Classification for Human Activity Recognition Using Inertial Measurement Unit (IMU) Time-Series Data
Get PDFHuman Activity Recognition (HAR) based on Inertial Measurement Unit (IMU) has become increasingly important in health and fitness applications. These systems can continuously and cost-effectively monitor human activity, regardless of the surrounding environment. However, the current dominant trend in HAR uses black box flat classification (FC) methods, which lack interpretability and do not consider the natural hierarchical relationship between activity classes. Such systems often achieve greater accuracy at the cost of increased complexity and are not suitable for critical decision-making applications. This paper proposes an Adaptive Hierarchical Decision Tree (AHDT) HAR system that recognizes human activities based on IMU measurements along with quasi-stationary inclination feature extraction. The proposed system generates a global classifier that classifies human activities according to a tree taxonomy structure. This approach maintains interpretability while considering the fundamental signal data features embedded in the natural hierarchical representation of the activity classes. In addition to the commonly used flat classification accuracy measures, we applied modified hierarchical accuracy measures to assess the exclusive characteristics of hierarchical relationships between the classes. We used seven publicly available datasets to evaluate the proposed system and compared its performance with other tree-based classifiers, including Random Forest, Gradient Boosting, XGBoost, and AdaBoost classifiers. Our results demonstrated that the AHDT system significantly improves the recognition performance of fine-grained activities and offers a balance between lower complexity and higher interpretability. Overall, the proposed AHDT system provides an interpretable and practical approach to HAR that can be valuable in critical decision-making applications
Exploring settler‑Indigenous engagement in food systems governance
Get PDFWithin food systems governance spaces, civil society organizations (CSOs) play important roles in addressing power structures and shaping decisions. In Canada, CSO food systems actors increasingly understand the importance of building relationships among settler and Indigenous peoples in their work. Efforts to make food systems more sustainable and just necessarily mean confronting the realities that most of what is known as Canada is unceded Indigenous territory, stolen land, land acquired through coercive means, and/or land bound by treaty between specific Indigenous groups and the Crown. CSOs that aim to build more equitable food systems must thus engage with the ongoing impacts of settler colonialism, learn/unlearn colonial histories, and build meaningful relationships with Indigenous peoples. This paper explores how settler-led CSOs engage with Indigenous communities and organizations in their food systems governance work. The research draws on 71 semi-structured interviews with CSO leaders engaged in food systems work from across Canada. Our analysis presents an illustrative snapshot of the complex and ongoing processes of settler-Indigenous engagement, where many settler-led CSOs aim to work more closely with Indigenous communities and organizations. However, participants also recognize that most existing engagements remain insufficient. We share CSOs’ practices, tensions, and lessons learned as reflections for scholars and practitioners interested in the continuous journey of building settler-Indigenous partnerships and reimagining more just and sustainable food systems, work which requires iterative and critically reflexive learning
Medicine for the soul: (Non)religious identity, coping, and mental health during the COVID-19 pandemic
Get PDFAlthough the threat and uncertainty of the COVID-19 pandemic has become a significant source of distress, using religion to cope may be associated with more positive health. Given the severity and chronicity of the pandemic, religious individuals may also have relied on a variety of non-religious coping methods. Much of the existing COVID-19 research overlooks the role of religious group membership and beliefs in relation to coping responses and associated mental health, with an additional lack of such research within the Canadian context. Thus, this cross-sectional study investigated relations among religiosity, stressor appraisals, (both religious and non-religious) coping strategies, mental and physical health in a religiously-diverse Canadian community sample (N = 280) during the pandemic’s 2nd wave from March to June 2021. Numerous differences were apparent in appraisal-coping methods and health across five (non)religious groups (i.e., Atheists, Agnostics, “Spiritual but not religious”, Christians, and those considered to be religious “Minorities” in Canada). Religiosity was also associated with better mental health, appraisals of the pandemic as a challenge from which one might learn or grow, and a greater reliance on problem-focused, emotional-engagement, and religious coping. Moreover, both problem-focused and emotional-engagement coping mediated the relations between religiosity and health. Taken together, this research has implications for individual-level coping as well as informing culturally-sensitive public health messages promoting targeted self-care recommendations with integrated religious or spiritual elements during times of threat and uncertainty, such as the COVID-19 pandemic
Fabrig : A Cloth-Simulated Transferable 3D Face Parameterization
No full text© 2024 ChangAn Zhu and Chris Joslin. This is the author’s version of the work. It is posted here for personal use. Not for redistribution. The definitive version was published in SA Conference Papers ’24 (SIGGRAPH Asia 2024), December 3–6, 2024, Tokyo, Japan, https://doi.org/10.1145/3680528.3687695.Existing 3D face parameterization methods are limited to human faces and/or require a large amount of manual work to prepare face-specific blendshapes. Unfortunately, many of the automated parameterization methods do not provide local controls for the different facial regions and methods that allow the integration of physics-based simulations also suffer from limited character compatibility and editability. We propose a human face anatomy-inspired 3D face parameterization method called Fabrig, which is quick to set up, transferable among various characters, easily editable, and compatible with physics-based simulations. Instead of using conventional volume-centric simulation for the face anatomy, our method innovatively uses cloth simulation for lighter computation. The parameterized faces support physics-based effects like collision and show skin details such as dynamic wrinkles. From our objective evaluation, we found that our method can parameterize the faces of various characters, ranging from realistic humans to non-humans, without any labor-demanding preparation work. The parameterized faces can be edited at the anatomical level while remaining intuitive to artists. Our evaluation results confirm that this new parameterization can accurately and naturally recreate the facial poses of a character or facial actions performed by a motion capture subject