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The role of the CUP-2 Derlin protein in maintaining niche positioning in C. elegans
No full textStem cells are undifferentiated cells that can either renew or develop into many different types of cells. The delicate balance between stem cell proliferation and differentiation is crucial for an organism’s growth and development. This balance is maintained by interactions within the stem cell niche, comprising stem cells and their surrounding environment. In the nematode C. elegans, the distal tip cell (DTC) is a niche for germline stem cells (GSCs), maintaining and interacting with them through Notch Signalling. We have identified a protein, CUP-2 (Derlin), which plays a role in regulating DTC positioning. In cup-2 mutants, the DTC becomes displaced proximally, migrating away from its normal position in a significant number of animals; however, the mechanism underlying this phenotype remains to be elucidated. I have found that a pair of other somatic cells (Sheath Cell pair 1) is not mispositioned in cup-2 mutants, suggesting that the mechanism maintaining DTC positioning is different than that for other gonadal somatic cells. Using SYGL-1::FLAG as a read-out of GLP-1/Notch signalling, I demonstrate that the region of active GLP-1/Notch signalling expands when the DTC is displaced, suggesting that it maintains its signalling ability in its new position. Finally, I demonstrate that disrupting the movement (or flux) of germ cells using fog-2 and glp-4 mutants, suppresses the DTC displacement phenotype in cup-2 mutants. Therefore, germ cell movement contributes to the displacement of the DTC in cup-2 animals. I propose that the DTC is attached to the moving germ cells and that they ‘drag’ the DTC more proximally as they move. Therefore, in cup-2 mutants, there may be more adhesion between the DTC processes and the germ cells. Alternatively, there may be less adhesion between the DTC body and the basement membrane at the distal end, which would normally counteract the dragging force of the moving germ cells
High-Performance Computing and Parallel Techniques for Scalable Optimization of Power System Transition Planning
No full textThis thesis introduces the Power System Transition Planning (PSTP) framework, formalizing a problem class in long-term transition planning problems that directly embraces the computational burden of realis-tic transition modeling. Unlike conventional Generation and Transmission Expansion (GTEP) or Macro-Energy-System approaches, which compromise on geospatial resolution, technology scope, or uncertainty representation to remain tractable, PSTP preserves these dimensions and tackles the resulting scale and complexity through decomposition and high-performance computing. Methodologically, the work (i) reassesses the role of high-performance computing (HPC) in power system optimization through a structured review and reporting guidance; (ii) formalizes PSTP and reformulates it into a dynamic-programming structure to enable Stochastic Dual Dynamic Programming (SDDP) and (iii) advances parallel SDDP with two contributions: a Nested Synchronous Parallel-by-Node (Nested-SPN) scheme tailored to Markov-chain uncertainty aggregation, and a Relaxed Fixed Integer Cut (RFIC) heuristic that strengthens cuts at modest overhead. Computational studies on an illustrative system (AESO-6) and a realistic, large-scale case (AESO-144) demonstrate that PSTP can be solved scalably, providing valuable insight, with interpretable policies. Rela-tive to conventional synchronous schemes, Nested-SPN reduces communication bottlenecks in large Markov decompositions and, together with RFIC, delivers materially faster convergence (up to 16× in reported trials) without sacrificing solution quality. The results shift the question from whether transition-scale stochastic planning is computationally feasible to how to design and schedule decomposition to sustain solvability as fidelity increases. The thesis closes by outlining directions for deeper integration of operations with planning and for hybrid decompositions that further expand the solvable boundary
Patient, clinician, and researcher prioritization of postoperative outcomes for people living with kidney failure: a modified Delphi process
No full textAbstract Background People with lived and living experience (PWLLE) of kidney failure have significantly high rates of surgery and postoperative complications. Despite these risks, there is lack of consensus on the most important postoperative outcomes for clinical care and research focused on this population. This study aimed to identify and compare the postoperative outcome priorities of PWLLE with those of clinicians/researchers. Methods We recruited PWLLE of kidney failure, clinicians and researchers from across Canada to complete a modified Delphi survey over three rounds between April and June 2024. Participants ranked 100 perioperative outcomes derived from literature, participant suggestions, and expert recommendations. Outcomes were evaluated for consensus using a 9-point Likert scale with predefined consensus criteria. Items not meeting consensus were either dropped or reconsidered in subsequent rounds. Median rankings of prioritized topics were compared between participant groups. Results Of 116 initial respondents, 91 consented to participate, with 64 (70%) completing all three rounds. Participants included 52 clinicians/researchers and 39 PWLLE. The top five prioritized postoperative outcomes were postoperative death within 30 days, intraoperative death, postoperative kidney allograft loss, septic shock, and 1-year postoperative mortality. Cardiovascular complications, dialysis dependency in individuals not requiring dialysis preoperatively, and risk of sepsis were also highly ranked. No significant differences were found in the top 10 priorities across participant groups (p > 0.05). Conclusion We identified key postoperative outcomes for people with kidney failure undergoing surgery. This work will inform future research on perioperative care and the development of postoperative risk prediction tools for PWLLE of kidney failure. Clinical trial number Not applicable
Social Media and Critical Digital Museum Pedagogy: A Multicase Study of Institutions in Alberta
No full textThe pedagogical dimensions of social media have been a topic of discussion in the museum sector for nearly 4 decades (Crow & Din, 2010). Recently, however, widespread institutional closures prompted by the onset of the COVID-19 pandemic have resulted in a rapid transformation in how and why museums engage with social media. A particularly notable development has been a surge in social media adoption, reported by over 50% of institutions (International Council of Museums, 2020). Despite its increasing popularity amongst museums, uses of social media are still being shaped by continuously evolving digital platforms, neoliberal institutional imperatives, and diverse organizational priorities—factors that complicate effective
and ethical social media use (Kidd, 2011). At the same time, the educational dimensions of museum social media practices remain largely underexamined and a more nuanced understanding of the informal and nonformal learning facilitated by museums’ social media engagement is critically needed. This study was driven by the following research question: How do museums and museum educators understand and engage with critical social media pedagogy? Further sub-questions included: How do museums engage in nonformal pedagogical activities on social media? What values and priorities drive these approaches? What assumptions or intentional choices about their audiences do museums make when developing content to engage with learners? Do competing priorities or interests influence museums’ approaches to social media pedagogy? How does social media facilitate informal learning about museums and their role in the community? The study was grounded in the field of Adult Education, focusing on public pedagogy and digital education. I adopted a multicase study methodology to provide in-depth insights into the phenomenon at the centre of this research by examining three large museums in Alberta, Canada. Data was gathered from three sources: online museum publications, social media content created by museums, and practitioner perspectives through semi-structured interviews and focus groups. I examined the data within a critical theoretical framework to apply a socially oriented, critical lens to practitioner and institutional perspectives surrounding this phenomenon. The findings are presented according to five tensions that emerged from the data as findings: conflicts between marketing and pedagogical objectives; balancing nonformal self-directed learning and collective learning; community-centred and authoritative pedagogical approaches; pleasing learners and critical pedagogical objectives; and quantitative or qualitative measures of success
Worn Lines: Healing Through the Marked Body
No full textThis exhibition is a personal exploration of tattooing as a tool for body reclamation and self-acceptance. Initially motivated by aesthetic appeal, my understanding of the importance of tattoos has deepened as I have examined how they have helped me reclaim my body from experiences of eating disorders and body dysmorphia. In a world that often objectifies and seeks to control women’s bodies, tattoos offer a means of reclaiming agency and asserting identity. Despite their growing popularity, tattoos, especially on women, continue to carry stigmas linked to deviancy and non-conformity. Through the lens of corporeal feminism, this exhibition reframes tattoos as acts of reparative care and bodily autonomy. Tattoos are not passive markings but intentional acts of self-determination, challenging harmful societal narratives and affirming self-worth. This exhibition consists of six realistic, figurative oil paintings and one installation piece, forming a visual narrative grounded in autotheory. These works trace my evolving relationship with my body, from struggles of body dysmorphia and eating disorders to experiencing self-acceptance and empowerment. Ultimately, this exhibition invites reflection on tattoos as transformative symbols of autonomy and healing. It encourages viewers to consider how tattoos can serve as tools of resistance, enabling reclamation and reshaping personal and cultural narratives around women’s bodies
Exploring the potential of machine learning in gastric cancer: prognostic biomarkers, subtyping, and stratification
No full textAbstract Background Advancements in the management of gastric cancer (GC) and innovative therapeutic approaches highlight the significance of the role of biomarkers in GC prognosis. Machine-learning (ML)-based methods can be applied to identify the most important predictors and unravel their interactions to classify patients, which might guide prioritized treatment decisions. Methods A total of 140 patients with histopathological confirmed GC who underwent surgery between 2011 and 2016 were enrolled in the study. The inspired modification of the partial least squares (SIMPLS)-based model was used to identify the most significant predictors and interactions between variables. Predictive partition analysis was employed to establish the decision tree model to prioritize markers for clinical use. ML models have also been developed to predict TNM stage and different subtypes of GC. Latent class analysis (LCA) and principal component analysis (PCA) were carried out to cluster the GC patients and to find a subgroup of survivors who tended to die. Results The findings revealed that the SIMPLS method was able to predict the mortality of GC patients with high predictabilities (Q2 = 0.45–0.70). The analysis identified MMP-7, P53, Ki67, and vimentin as the top predictors. Correlation analysis revealed different patterns of prognostic markers in the non-survivor and survivor cohorts and different GC subtypes. The main prediction models were verified via other ML-based analyses, with a high area under the curve (AUC) (0.84–0.99), specificity (0.82–0.99) and sensitivity (0.87–0.99). Patients were classified into three clusters of mortality risk, which highlighted the most significant mortality predictors. Partition analysis prioritizes the most significant predictors P53 ≥ 6, COX-2 > 2, vimentin > 2, Ki67 ≥ 13 in mortality of patients (AUC = 0.85–0.90). Conclusion The present study highlights the importance of considering multiple variables and their interactions to predict the prognosis of mortality and stage in GC patients through ML-based techniques. These findings suggest that the incorporation of molecular biomarkers may enhance patient prognosis compared to relying solely on clinical factors. Furthermore, they demonstrate the potential for personalized medicine in GC treatment by identifying high-risk patients for early intervention and optimizing therapeutic strategies. The partition analysis technique offers a practical tool for identifying cutoffs and prioritizing markers for clinical application. Additionally, providing Clinical Decision Support systems with predictive tools can assist clinicians and pathologists in identifying aggressive cases, thereby improving patient outcomes while minimizing unnecessary treatments. Overall, this study contributes to the ongoing efforts to improve patient outcomes by advancing our comprehension of the intricate nature of GC
Challenges of the COVID-19 Pandemic for Recreational Group Physical Activities for Older Adults: Participant and Service Provider Perspectives
No full textBackground: Social participation and physical activity are lifestyle factors that improve well-being and health. Older adult populations are at greater risk of inactivity and social isolation, both of which were exacerbated by COVID-19 restrictions (e.g., physical distancing, recreational program closures). Recreational programs that provide opportunities for physical activity and social interaction are important for addressing these concerns in communities. This research examined lived experiences with changes in physical activity and social participation among adults >65 years old during the COVID-19 pandemic, their perspectives on precautionary measures and alternate forms of program delivery, and experiences and challenges service providers in the recreation sector faced in adapting programs for older adults during the pandemic.
Methods: Using interpretive description methodology we interviewed older adults (n = 20) and service providers (n = 10).
Results: Four themes were identified: (1) concerns about safety and risk given heightened vulnerability, (2) alternate options helped with participation but inequities in access persist, (3) forging new routines after a major lapse, and (4) social connections supported resilience but sense of community dwindled.
Conclusion: It is important that organizations balance risks of participation with non-participation; address the compounding challenges and inequities of a disruption; understand the importance of social benefits of physical activity in this population; and plan to support resilience, cope with the aftermath of COVID-19, and prepare for future challenges.The authors would like to acknowledge funding from a Social Sciences and Humanities Research Council of Canada Partnership Engage Grant COVID-19 Special Initiative, and in-kind support from The City of Calgary.Social Sciences and Humanities Research Council (SSHRC
Associations between digital media use behaviours, screen time and positive mental health in youth: results from the 2019 Canadian Health Survey on Children and Youth
No full textAbstract Background Limited research has examined associations between a range of digital media use (DMU) behaviours and screen time measures with positive mental health (PMH) outcomes among Canadian adolescents. This study examined these associations among a large sample of Canadian youth. Methods We used self-reported data from youth aged 12–17 years in the 2019 Canadian Health Survey on Children and Youth (N = 10,695). DMU behaviours included frequency of using social media, video/instant messaging and online gaming. Screen time included estimated hours spent watching content, playing video games and overall sedentary electronic device usage in the past week. PMH outcomes included self-rated mental health (SRMH), life satisfaction, happiness, autonomy, competence and relatedness. We conducted gender-stratified adjusted logistic regression analyses. Results Girls reporting using social media constantly (vs. never or less than weekly) were less likely to report high SRMH, life satisfaction, happiness, autonomy and competence, while their video/instant messaging frequency was unrelated to PMH outcomes. Social media use and video/instant messaging frequency tended to be unrelated to PMH outcomes among boys (or positively associated at moderate levels in a few exceptions). Boys and girls reporting online gaming constantly (vs. never or less than weekly) were less likely to report high happiness, autonomy, competence and relatedness. Boys watching content for 14+ (vs. < 3) hours in the past week had lower odds of high SRMH, life satisfaction and happiness, while girls watching 7+ (vs. < 3) hours had lower odds of all PMH outcomes. Boys and girls reporting 21+ (vs. < 3) hours of overall sedentary electronic device use in the past week had lower odds of all PMH outcomes. Conclusions This study provides support for a link between some DMU behaviours and screen time measures with lower PMH among Canadian youth. Findings can assist in the promotion of public health strategies targeted towards promoting reduced and/or non-problematic DMU and screen time, and improved well-being, as well as the continued surveillance of DMU, screen time and PMH outcomes among Canadian youth
Confronting Epistemic Violence: The Kaurs' Resistance Against 1984
No full textThis research investigates the epistemic erasure of Kaur’s (Sikh women) experiences of the Delhi Ghallughara in 1984, a state-enabled massacre of Sikhs in postcolonial India. Employing abductive analysis, three datasets were analysed: documentaries providing oral accounts of survivors and witnesses, archives of newspaper excerpts, and legal reports. Adopting the lens of Southern decolonial feminist framework rooted in Sikh epistemologies, Qualitative Content Analysis (QCA) and Critical Discourse Analysis (CDA) were implemented to explore: (1) the communal and gendered dimensions of 1984; (2) state-enabled structural silencing (3) how narratives have been re-narrated, through memory and epistemic erasure. Findings reveal that the Kaurs were not simply passive victims of communal violence, due to their gendered vulnerabilities, but they navigated immense violence with resistance and strategic silence. However, their testimonies remain underrepresented in newspapers, legal reports, and scholarly work. This paper argues that such erasure is not incidental, but rather systemically reinforced by cultural and patriarchal norms that intersect with political and institutional hierarchies. By centring the voices of Kaurs of 1984 and representing their stories, this study challenges dominant modes of knowledge production and calls for feminist reparative justice by legitimising their epistemologies and challenging systems that continue to silence them
Advanced Doherty Amplifier Architectures for Efficiency and Linearity Enhancement of Wireless Transmitters
No full textRF power amplifiers (PAs) are essential components in wireless transmitters. They amplify the message signal before it is transmitted through a lossy channel to the receiver, ensuring that the signal can be suc-cessfully detected. The performance of these amplifiers is critical, as they are often the most power-hungry and nonlinear elements in RF transmitters. Enhancing power efficiency not only reduces cooling costs but also extends the lifespan of high-power components. Furthermore, maintaining sufficient linearity is crucial to ensure high-quality signal transmission, enabling the receiver to accurately interpret the signals without interfering with adjacent communication channels. The characteristics of the message signal are considered in determining the requirements for efficiency and linearity of power amplifiers. Statistically, most symbols in the message signal tend to have similar magnitude values; however, the peak symbol can be significantly higher than the average. The difference between the peak and average magnitudes is known as the peak-to-average power ratio (PAPR). This ratio is specified in communication standards and can vary, ranging from 7 dB in WCDMA to 12 dB in the 5th generation of
wireless communications. As a result, the power amplifier must maintain both linearity and efficiency across a wide range of signal values, from small to large. Doherty power amplifiers (DPAs) are commonly used in wireless communication among various PA topolo-gies. They provide high efficiency at lower power levels, making them an excellent choice for meeting the high PAPR requirements of wireless communications. However, designers encounter several challenges in their implementation, including complex nonlinear behavior, three-port combiner design, bandwidth limi-tations due to the quarter-wavelength transmission line in the combiner topology, and a drop in efficiency within the high-efficiency region, referred to as the load-modulated region. This research aims to enhance the performance of DPAs through several steps, with a focus on linearity, bandwidth, and efficiency. Since W.H. Doherty invented the Doherty amplifier in 1936, there has not been an accurate description of its performance. Our research addresses this gap. We provide a theoretical analysis of Doherty amplifiers based on the model of basic classic amplifiers developed by S.C. Cripps. We then extend this model to propose a design methodology for dual-input Doherty power amplifiers, where the input signal splitting ratio between the sub-amplifiers can dynamically change with the power level. Our study also reveals that efficiency drops within the load-modulated region of a conventional Doherty power amplifier due to the carrier amplifier’s inability to remain voltage-saturated. The design methodology of dual-input DPAs discusses a new hyper- parameter introduced by dynamic signal splitting to the Doherty configuration, along with the necessary adjustments on the operating point of the peaking amplifier. It then recommends a digitally dynamically input signal splitting pattern to maximize efficiency by maintaining the carrier amplifier in saturation within the region. The discussion also considers the negative impact of dynamic signal splitting on the linearity of DPA and introduces a predistortion function based on the input signal splitting pattern that restores class AB-like linearity in digital Doherty amplifiers. The proposed design methodologies for both conventional and digital Doherty amplifiers are based on the ideal large signal model of transistors. However, this research also investigates how non-idealities in the combiner and sub-amplifiers affect the performance of a DPA. It identifies all sources of nonlinearity and presents a tuning method to minimize phase distortion in the overall response of the DPA. To practically evaluate the performance of digital Doherty amplifiers, this research recommends integrat-ing the conventionally measured DPA response with the proposed optimal input signal splitting patterns, along with the phase distortion mitigation method. This approach effectively addresses hidden sources of
nonlinearity within the input signal bandwidth that may be overlooked by the theoretical model. Validation experiments were conducted on a 50 W dual-input DPA designed for 5G wireless communications, built using two GaN 25 W Cree transistors operating in a frequency range of 3.3 GHz to 3.7 GHz. The tests were conducted by applying a 90 M Hz modulated test signal at 3.5 GHz, which showed significant improvements in both efficiency and linearity of the prototype compared to those of a conventional Doherty amplifier. Digital Doherty amplifiers have shown strong performance, but this comes at the cost of increased hard-ware complexity. Each sub-amplifier requires a separate input path to process the input signal at baseband frequency before converting it to RF level. To address this challenge and simplify the hardware of wireless transmitters, this research next explores an analog solution for efficiently splitting the main RF signal be-tween the inputs of Doherty amplifiers. The optimal input signal splitting patterns from our initial study on the digital dual-input Doherty serve as the expected response for the dynamic analog signal splitter. These patterns can be realized using RF current sources, or more precisely, basic RF amplifiers. The search for a dynamic analog signal splitter led to the development of a novel architecture known as the ”Doherty Power Amplifier with RF Current Source Excitation” (DPA-w/RCS). This design focuses on a specific input signal splitting pattern that re- quires both sub-amplifiers to operate close to Class B. This differs from traditional Doherty power amplifier designs, where the peaking amplifier typically operates in deep Class C to delay its contribution. The new approach results in significant improvements in linearity while maintaining high efficiency. To showcase the performance of this new topology, we designed a prototype using 0.25μm GaN MMIC technology from the UMS manufacturer. The prototype, interestingly and unexpectedly, exhibited increased bandwidth, which the model had not predicted. More investigation is needed on this secondary outcome. The electromagnetic simulation of the prototype demonstrates a peak power of 39 dBm and an efficiency range of 40% − 57% in the 6 dB back-off region across the frequency range of 3.3 − 4.3 GHz