30921 research outputs found
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Quantized matrix completion through bilinear factorization and approximate message passing
No full textCompressed sensing is an exciting, quickly developing field, pulling in significant consideration in electrical engineering, applied mathematics, statistics, and software engineering. It can likewise serve computer vision, coding theory, signal processing, image processing, and algorithms for efficient data processing. Compressed sensing gives an exquisite framework for recuperating signals from compressed measurements. In this regard, our main focus in this thesis is the problem of bilinear factorization of sub-sampled matrices, also known as matrix factorization (MF), which has different variations, such as unconstrained MF, integer MF (IMF), non-negative MF (NMF), probabilistic MF (PMF), to cite a few. In this thesis, we introduce a new Bayesian quantized MF solution based on the approximate message passing (AMP) framework to solve the discrete matrix completion (MC) problem. Specifically, we resort to the bilinear generalized vector AMP (BiG-VAMP) algorithm along with a quantizer, and an expectation-maximization (EM) learning procedure to optimize the quantization thresholds. This approach enables our algorithm to jointly recover two matrices, denoted as U and V, as well as their real-valued and quantized product matrices from an incomplete discrete low-rank matrix Y, observed through a component-wise selection transformation. Extensive computer simulations, based on synthetic and real-world discrete datasets, show that the proposed method outperforms the state-of-the-art techniques for MF with discrete-valued factors in terms of reconstruction performance. Moreover, we conduct a theoretical performance analysis of the proposed method, based on the state evolution (SE) framework, and show its consistency with the empirical MSE performance obtained by computer simulations.May 202
Lipoxygenase-derived oxylipins are enriched in anti-citrullinated protein antibody (ACPA)-positive individuals at risk for developing rheumatoid arthritis
No full textBackground
Rheumatoid arthritis (RA) is typically preceded by an extended preclinical period where circulating autoantibodies, particularly anti-citrullinated protein antibodies (ACPA), are detectable in the absence of clinical arthritis. Increased dietary intake of anti-inflammatory omega-3 (ω3) polyunsaturated fatty acids (PUFA) has been shown to be associated with a lower the risk of developing incident RA in large epidemiological studies. It is currently not known how changes in fatty acid (FA) metabolism may impact on the progression towards RA in at-risk individuals. To begin to address this question, we profiled serum FAs and oxylipins in an established cohort of at-risk ACPA-positive first-degree relatives (FDR) of RA patients (N = 31), some of whom developed RA (N = 4), and compared their profile to ACPA-negative FDR from the same population (N = 10).
Methods
Gas chromatography (GC) was used for FA quantitation. Oxylipins were extracted and quantified using high-performance liquid chromatography–tandem mass spectrometry (HPLC/MS/MS).
Results
Although we did not detect any meaningful differences in overall FA content between ACPA + and ACPA − FDR, the levels of oxylipins derived from FA metabolism demonstrated significant differences between the two groups, with the ACPA + group demonstrating enrichment in circulating arachidonic acid- and eicosapentaenoic acid-derived molecules. Compared with the ACPA − FDR group, the ACPA + FDR, including those who progressed into inflammatory arthritis, displayed higher levels of LOX-derived oxylipins.
Conclusion
ACPA seropositivity in otherwise unaffected individuals at-risk for developing future RA based on family history (FDR) is associated with alterations in the serum oxylipin profile that suggests dysregulated LOX activity
A historical, cultural, and political analysis of oppression and resistance: The case of the Emberá Chamí community in Colombia
No full textDesigning and conducting studies on Indigenous resistance within conflict contexts necessitates a comprehensive and participatory endeavor that incorporates diverse perspectives and viewpoints. This undertaking is intricate due to the multifaceted nature of the actors involved in power dynamics and control strategies, as well as the complex dynamics of Indigenous communities and the array of resistance tactics employed for their survival. Further, studying resistance entails overcoming the binary approach often found in academic literature, which typically dichotomizes resistance into violent and nonviolent categories.
This thesis research employed a qualitative and Indigenous research methodology to explore the mechanisms of resistance among the Emberá Chamí Indigenous community, their evolution over time, the contextual factors influencing the Indigenous group, and the power strategies they have encountered. Thus, the study
comprised of semi-structured interviews as well as a documentary and participatory historical analysis of resistance tactics, focusing on the Tatamá region and the present day Unified Chamí Indigenous Reservation of the San Juan River in Colombia. Data generation was conducted in 2023.
The study organizes the data analysis into four historical periods: the conquest, the colonial era, the emergence of republicanism, and the Colombian armed conflict.
The conquest period delves into the ideological underpinnings of imperial Spain that shaped its domination strategies and elicited resistance from the Emberá Chamí’s ancestors. The colonial era evidenced changes in power dynamics and the persistence of resistance tactics, along with the incorporation of the Emberá Chamí’s new survival elements. The republican period examines political and migratory phenomena as forms of internal colonization that spurred novel resistance processes. Finally, the thesis research explores the impact of the current Colombian armed conflict on the reservation and how the Emberá Chamí’s communities and leaders have confronted it using legal and philosophical frameworks rooted in Indigenous rights and sumac kawsay (good living). This study underscores the significance of analyzing Indigenous people’s resistance processes while embracing their diverse perspectives and navigating the complexities of social phenomena.Dr. John J. Stapleton, KSG Peace and Conflict Studies Graduate FellowshipFebruary 202
A mixed methods exploration of the characteristics, dynamics, processes and perceived effects of research partnerships in child health
No full textBackground: Research partnerships between health researchers and knowledge users (e.g., children and youth, parents and families, healthcare providers) are gaining momentum to promote the uptake and application of research. Yet, comprehensive data on partnerships within child health research that include partnership traditions and knowledge user groups remains limited. This dissertation addresses this gap by exploring child health as a unique context for research partnerships, focusing on their characteristics, dynamics, processes, and effects.
Methods: This dissertation adopts an exploratory mixed-methods approach across three concurrent studies, employing multiple data collection and analysis methods while maintaining conceptual coherence and a pragmatic philosophical orientation, integrating findings in the discussion. Objective 1 characterized knowledge user engagement in published child health research through a scoping review, examining characteristics, practices, barriers, facilitators and effects. Objective 2 used interpretive description to provide an in-depth understanding of the experiences, motivations, and relational dynamics of engaging in research partnerships among Canadian child health researchers and knowledge users. Objective 3 employed a concurrent mixed-methods design to explore considerations influencing the individual determinants and perceived effects of partnered child health research compared to other health research contexts, through secondary analysis of a cross-sectional survey of Canadian partnered health research projects funded from 2011-2019 and interviews with child health researchers and knowledge users informed by qualitative description.
Results: Objective 1 revealed a growing trend in publications on child health research partnerships, particularly since 2019. Most studies used community-based participatory research approaches and engaged multiple knowledge user groups, though reporting on barriers, facilitators, and effects varied. Objective 2 highlighted role-specific motivations for partnering and underscored the central role of relationships in shaping partnership dynamics, sustainability, and the ability to navigate challenges. Researchers often balanced evolving partnership practices within academic systems and structures not always conducive to collaboration, resulting in tensions. Objective 3 found no significant differences between child and general health cohorts in survey responses. Child health respondents reported positive perceptions of their capability, opportunity, and motivation to work in partnership, but mixed views on project effects. Interview participants embraced common principles across research contexts while navigating additional logistical (e.g., institutional processes) and practical (e.g., engaging proxies) challenges unique to partnered child health research. Participants noted distinct considerations (e.g., safeguarding vulnerable populations), processes (e.g., tailoring engagement strategies) and effects when engaging children and youth, with the ethos of the child health community facilitating partnerships.
Conclusion: Overall, research partnerships in child health share common principles and challenges with those in other health research contexts, but also have unique characteristics, dynamics, and processes that add nuance to the conceptualization and practice of partnering. These findings provide a foundational understanding of child health research partnerships, guiding efforts to optimize partnership research and practice. By deepening our understanding of these elements, partners can work toward meaningful collaborations that enhance child health research uptake and effects.Research Manitoba and Children's Hospital Research Institute of Manitoba
Manitoba Training Program for Health Services ResearchFebruary 202
Quantitative genetics of polar bear (Ursus maritimus) behaviours
No full textConflict plays a central role in sexual selection by shaping the behaviours and traits that contribute to reproductive success. It drives competition between individuals, influences mate choice and mating strategies, and ultimately shapes the evolution of sexual dimorphism, courtship displays, and other aspects of reproductive behaviour in many species. Informing conservation management strategies aiming at reducing human-wildlife conflicts involves understanding the interplay of genetic, social, and environmental effects on behavioural phenotypic variation. The objectives of this thesis were to investigate the heritable and non-heritable dynamics shaping complex human-polar bear (Ursus maritimus) conflict risk behaviour observed in Churchill, Manitoba. The study aims to understand the influence of climate change and human settlements on population-level behaviour, and understand the individual-level influences of innate, social, and remaining environmental cues driving polar bear conflict risk behaviour expressed by individuals within the Western Hudson Bay subpopulation. These concepts build on the foundations of quantitative genetics and animal behaviour, using data from an extensively monitored wild polar bear subpopulation near Churchill, Manitoba. The findings suggest that conflict risk behaviour is very closely tied to individuals’ ability to survive and reproduce, and that polar bears have a high affinity for environmental learning and for avoiding serious conflicts. Dynamics in conflict risk behaviour over time underscore the influence of environmental stressors, contrasting with minimal cohort effects. Conservation management strategies focused on reducing human-wildlife conflicts should aim to improve the environmental conditions for wildlife by preserving habitat quality and connectivity.University of Manitoba Graduate FellowshipOctober 202
Addressing gaps in community-level antimicrobial resistance monitoring through wastewater surveillance
No full textAntimicrobial resistance (AMR) is an escalating global health crisis, yet existing monitoring
systems inadequately track AMR at the community level. Wastewater surveillance (WS) offers a
practical solution by providing a scalable, non-invasive approach to monitor community-level
AMR. This thesis contributes to the development of a national WS program in Canada,
enhancing our capacity to detect and manage AMR. Central to this work was the advancement
and validation of a wastewater-specific quantitative metagenomic (wqMeta) workflow, designed
to enrich and quantify thousands of AMR gene families in diverse wastewater samples.
A DNA extraction method was optimized, comparing two extraction kits—PowerMicrobiome
(PMB) and MagNA Pure 96 (MP96). Processing 100 mL of wastewater with the PMB kit
consistently yielded higher DNA concentrations and quality, enabling more effective
downstream analyses. The wqMeta workflow, which normalized data by both total bacterial load
and wastewater flow rates, outperformed the published qMeta method, which relied solely on
bacterial load. The wqMeta approach closely mirrored quantitative PCR (qPCR) in its ability to
quantify absolute AMR gene abundances, demonstrating superior accuracy and scalability.
A nine-week pilot study across six wastewater treatment plants (WWTPs) in urban, rural, and
remote communities in central Canada validated the workflow. Results revealed stable AMR
concentrations over time, with significant spatial differences: urban sites exhibited higher AMR
levels and gene diversity compared to remote sites, highlighting the influence of population
density on AMR dissemination. This study underscores the potential of WS to bridge critical
gaps in AMR monitoring and offers actionable insights for public health interventions.
The findings demonstrate that WS, supported by advanced methodologies such as wqMeta, can
provide real-time, population-wide AMR data. Implementing a national WS program would
strengthen Canada’s ability to detect and respond to AMR trends, guiding evidence-based policy
decisions to mitigate the growing threat of AMR.February 202
Divergent maturational patterns of the infant bacterial and fungal gut microbiome in the first year of life are associated with inter-kingdom community dynamics and infant nutrition
No full textBackground
The gut microbiome undergoes primary ecological succession over the course of early life before achieving ecosystem stability around 3 years of age. These maturational patterns have been well-characterized for bacteria, but limited descriptions exist for other microbiota members, such as fungi. Further, our current understanding of the prevalence of different patterns of bacterial and fungal microbiome maturation and how inter-kingdom dynamics influence early-life microbiome establishment is limited.
Results
We examined individual shifts in bacterial and fungal alpha diversity from 3 to 12 months of age in 100 infants from the CHILD Cohort Study. We identified divergent patterns of gut bacterial or fungal microbiome maturation in over 40% of infants, which were characterized by differences in community composition, inter-kingdom dynamics, and microbe-derived metabolites in urine, suggestive of alterations in the timing of ecosystem transitions. Known microbiome-modifying factors, such as formula feeding and delivery by C-section, were associated with atypical bacterial, but not fungal, microbiome maturation patterns. Instead, fungal microbiome maturation was influenced by prenatal exposure to artificially sweetened beverages and the bacterial microbiome, emphasizing the importance of inter-kingdom dynamics in early-life colonization patterns.
Conclusions
These findings highlight the ecological and environmental factors underlying atypical patterns of microbiome maturation in infants, and the need to incorporate multi-kingdom and individual-level perspectives in microbiome research to improve our understandings of gut microbiome maturation patterns in early life and how they relate to host health.
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Virtual simulation in healthcare education: a multi-professional, pan-Canadian evaluation
Get PDFBackground
As we experience a shortage of healthcare providers in Canada, it has become increasingly challenging for healthcare educators to secure quality clinical placements. We evaluated the impact of virtual simulations created for the virtual work-integrated learning (Virtu-WIL) program, a pan-Canadian project designed to develop, test, and offer virtual simulations to enrich healthcare clinical education in Canada. Evaluation was important since the virtual simulations are freely available through creative commons licensing, to the global healthcare community.
Methods
Students self-reported their experiences with the virtual simulations and the impact on their readiness for practice using a survey that included validated subscales. Open-ended items were included to provide insight into the students’ experiences.
Results
The evaluation included 1715 Nursing, Paramedicine and Medical Laboratory students enrolled in the Virtu-WIL program from 18 post-secondary universities, colleges, and institutions. Results showed most students found the virtual simulations engaging helped them learn and prepare for clinical practice. A key finding was that it is not sufficient to simply add virtual simulations to curriculum, careful planning and applying simulation pedagogy are essential.
Conclusion
Virtual simulation experiences are increasingly being used in healthcare education. Results from this rigorous, large-scale evaluation identified ways to enhance the quality of these experiences to increase learning and to potentially decrease the number of hours healthcare students need in clinical practice to meet professional competencies. Further research is needed regarding many aspects of virtual simulations and, in particular, curriculum integration and the timing or sequencing of virtual simulations to best prepare students for practice.Highlights
• We investigated the effectiveness of virtual simulation in post-secondary healthcare education
• This is one of the first evaluations to include a national sample of post-secondary students and virtual simulation.
• Virtual simulation, when sound pedagogy and curriculum planning are applied, can be an engaging and effective way for students to prepare for clinical practice
Decreasing internalized ageism: development, feasibility, and effectiveness of a process-based intervention
Get PDFA lifetime of exposure to ageism may be internalized in older adults, and these ageist beliefs that are directed inwards can have severe consequences. Unfortunately, research on reducing internalized ageism is scarce. To address this, I designed and implemented a six-week process-based intervention to reduce internalized ageism. This intervention utilized education, acceptance and commitment therapy, and attributional retraining. I evaluated the feasibility and effectiveness of this intervention in reducing internalized ageism, and the mechanisms through which it achieved this reduction. A total of 81 participants consented to the feasibility portion of the study, and 78 consented to the effectiveness portion of the study. Regarding feasibility, the program was evaluated overwhelmingly positively. Most participants rated each session and the overall program as very useful and indicated that it changed their perspectives on ageism. The program also maintained impressive engagement, with only three participants dropping out of the program, and the majority completing the between-session activities. Participants also attributed a wide range of novel behaviours to this intervention. Regarding effectiveness, participants’ internalized ageism was substantially reduced following the intervention and this was maintained at a two-month follow up; improvements were associated with large effect sizes. Additionally, this reduction of internalized ageism was mediated by increases in psychological flexibility, mindfulness, and perceived control. Altogether, this study provides a promising foundation from which to advance research on interventions that address the problem of internalized ageism – a problem that has severe consequences on the health and well-being of growing numbers of older adults in every country around the world.Dr. Richard Douglas Oatway Memorial FellowshipOctober 202
Assessing sub-regional wealth Inequalities in the ANCq - a content-qualified antenatal care (ANC) coverage indicator in Pakistan: evidence from the MICS surveys 2017-2020.
No full textThe rate of progress towards achieving the Sustainable Development Goals for maternal health in Pakistan has been exceedingly slow. Maternal health indicators are disappointingly some of the lowest, and inequalities in those indicators are some of the highest in the region, necessitating urgent and accelerated efforts to expand access to the most marginalized and disadvantaged groups. An analysis of wealth-based inequalities in the ANCq – a content-qualified antenatal indicator, with a particular focus on understanding these inequalities within and between provinces is presented. Considering Pakistan's 18th Constitutional Amendment and the devolution of healthcare, identifying these inequalities at the sub-provincial level is ever more crucial. Methods This study analyzed data from the 2017-20 Multiple Indicator Cluster Surveys (MICS) to examine the wealth-based inequalities in the components of the ANCq as well as the weighted mean of the ANCq using simple and complex measures of inequality in districts as well as tiers of districts within each province. Overall, the study supports the conclusion that stark inter-provincial and sub-provincial wealth-based disparities exist in the coverage of antenatal care and its components. Similar ANCq scores in the poorest wealth quintiles in both developed and less-developed districts suggest that health resource benefits are not only unevenly distributed, in some respects, they harm equity by widening gaps in coverage. Economically disadvantaged populations continue to face major barriers in accessing high-quality antenatal care even in areas with better health infrastructure, underscoring the need for comprehensive strategies to ensure equitable healthcare for all.October 202