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Individualized PEEP can improve both pulmonary hemodynamics and lung function in acute lung injury
Get PDFAbstract Rationale There are several approaches to select the optimal positive end-expiratory pressure (PEEP), resulting in different PEEP levels. The impact of different PEEP settings may extend beyond respiratory mechanics, affecting pulmonary hemodynamics. Objectives To compare PEEP levels obtained with three titration strategies—(i) highest respiratory system compliance (CRS), (ii) electrical impedance tomography (EIT) crossing point; (iii) positive end-expiratory transpulmonary pressure (PL)—in terms of regional respiratory mechanics and pulmonary hemodynamics. Methods Experimental studies in two porcine models of acute lung injury: (I) bilateral injury induced in both lungs, generating a highly recruitable model (n = 37); (II) asymmetrical injury, generating a poorly recruitable model (n = 13). In all experiments, a decremental PEEP titration was performed monitoring PL, EIT (collapse, overdistention, and regional ventilation), respiratory mechanics, and pulmonary and systemic hemodynamics. Measurements and main results PEEP titration methods resulted in different levels of median optimal PEEP in bilateral lung injury: 14(12–14) cmH2O for CRS, 11(10–12) cmH2O for EIT, and 8(8–10) cmH2O for PL, p < 0.001. Differences were less pronounced in asymmetrical lung injury. PEEP had a quadratic U-shape relationship with pulmonary artery pressure (R2 = 0.94, p < 0.001), right-ventricular systolic transmural pressure, and pulmonary vascular resistance. Minimum values of pulmonary vascular resistance were found around individualized PEEP, when ventilation distribution and pulmonary circulation were simultaneously optimized. Conclusions In porcine models of acute lung injury with variable lung recruitability, both low and high levels of PEEP can impair pulmonary hemodynamics. Optimized ventilation and hemodynamics can be obtained simultaneously at PEEP levels individualized based on respiratory mechanics, especially by EIT and esophageal pressure
Dynamic scene modeling in agent-based survival simulation
Get PDFAgent-based models (ABMs) simulate agents and the interactions between agents and their environments. We focus on the coevolution of prey and predator ABM. This thesis proposes to train agent models for increased accuracy in scene modeling by selecting agents capable of recognizing and modeling the relative locations of landmarks in their simulated environment to test and demonstrate the feasibility of this method. There are, therefore, two goals to this thesis. First, to develop a simulation-based technique for training AI agents in proficiency of scene modeling using population level “survivability” metrics. Since scene modeling is viewed as a competitive advantage
in terms of survival in nature, the research investigates whether a survival
simulation is a sufficient motivation for selecting agents capable of accurately modeling their surroundings. Through experiments, we demonstrate the effectiveness or ineffectiveness of this ABM-inspired survival simulation as a viable training method for simulating complex behaviors. Second, we show how procedural generation techniques can extend existing ABMs into the third dimension and allow the rendering of this environment from several unique perspectives. This extension opens the door between simulated robotics and the large base of available ABM models, allowing new methods for comparing robot behaviors in highly dynamic environments.May 202
Reconstructing tradition and social engagement in Buddhist studies: The Foundation for the Preservation of the Mahayana Tradition
Get PDFIn Buddhist Studies, forms of Buddhism their practitioners call “traditional” are often excluded from research, stereotyped in negative ways, or deemed modern. This practice affects two sub-fields of Buddhist Studies: studies of contemporary Buddhism and of Buddhist social engagement. Overlooking traditional-identified forms of Buddhism when studying contemporary Buddhism or categorizing them as modern has led to not exploring their histories, features, and activities. Overlooking traditionalist Buddhists’ socially beneficial activities has led to portraying modernists’ engagement as all of Buddhists’ engagement and not identifying features of engagement particular to traditionalists. Both sub-fields thus produce incomplete pictures of today’s Buddhisms and Buddhists.
To address these gaps, ethnographic and textual research was undertaken on the Foundation for the Preservation of the Mahayana Tradition (FPMT), a large transnational organization that describes its Buddhism as traditional. Research determined the bases on which people in FPMT label their Buddhism “traditional” and used these to develop a stipulative definition of “traditional Buddhism” that avoids stereotypes and enables scholars to distinguish traditional from other forms of Buddhism. Adding a category for “traditional Buddhism” to Buddhist Studies, paralleling “modern Buddhism” and “postmodern Buddhism,” will make understudied types of Buddhism more visible, increasing research on them and improving understanding. The dissertation then addresses scholars’ view that social engagement is undertaken only by modernist Buddhists by showing that FPMT is socially engaged and describing the impetus, nature, and features of its engagement. It then posits that a category of “traditionalist social engagement,” with particular characteristics, can usefully be added to the study of engaged Buddhism. The dissertation thus finds its place within scholarship on contemporary Buddhism and Buddhist social engagement, adding data and advancing theoretical discussions in these areas as well as contributing new research on FPMT, an influential and globally active, but little-studied, Buddhist organization.May 202
A cross-national, cross-sectional study of women's retention and advancement in Information Technology (IT) and Engineering careers – Germany Report
Get PDFThis report offers summary results from the Germany survey of the Cross-National, Cross-Sectional Study of Women’s Retention and Advancement in Information Technology and Engineering Careers project.
Women continue to be underrepresented in science, technology, engineering, and mathematic (STEM) fields. This project highlights factors that contribute to the retention and attrition rates of women working in engineering and information and communication technology (EICT) jobs across Canada, Sweden, and Germany. The primary objective of this project is to identify the impact of welfare state entitlements, job factors, and family/individual circumstances on women’s intent to stay or leave their jobs.
Our findings from the Germany survey suggest that job-related factors such as limited contract terms, dissatisfaction with salary, few promotion opportunities, and hostile climate are the main reasons for respondents’ job attrition. As well, turnover intention is impacted by experiences of workplace hostility, incivility, and harassment; lack of work-life balance; and workplaces that are gender-biased and/or unsupportive of women. Therefore, supportive workplaces that promote job security, work-life balance, good pay, peer inclusion, and work autonomy can improve job retention.
Improvements to welfare state entitlements for childcare, elder care, child-related benefits, parental leave, and illness/injury leave may also reduce the pressures of work-life interference and improve the work-life balance of EICT women who continue to be primary caregivers. The respondents for the Germany survey also highlight the continued presence of gendered informal and formal networks that are male-dominated within EICT workplaces. It remains a challenge to find “good” mentors and mentors of diversity that can assist them with career advancement.
Another objective of this study is to evaluate the impact and variation of these circumstances by employment sector and work type. We directly compared the experiences of women working in engineering to computer science and information technology (CSIT), as well as women working in the academic sector to the non-academic sector. Our findings indicate that there are pros and cons to working in each work area and/or sector. Broadly, there is more job retention within the academic sector compared to non-academic sector but there are challenges to obtaining permanent employment in the academic sector. We find no notable differences in the turnover intention of engineering and CSIT respondents. However, engineering respondents are overall more satisfied with their careers and experience less workplace alienation than CSIT respondents.
In the future, we will compare these results to similar surveys administered in Sweden and Canada to uncover potential similarities and differences in job attrition and retention cross-nationally. Overall, the statistical analysis demonstrates that, despite increased efforts to improve gender equity across STEM fields, gender inequalities, stereotypes, and biases remain problems within EICT in Germany, shaping women’s day to day workplace experiences across employment sectors.
We would like to thank the Social Sciences and Humanities Research Council for their support and funding of this project
Is Empagliflozin equivalent and/or synergistic with ACE inhibition in the prevention of chemotherapy mediated cardiotoxicity?
No full textBackground: Breast cancer is a major public health concern in Canada. Doxorubicin and Trastuzumab (DOX+TRZ) are two of the most common anti-cancer drugs used in the treatment of breast cancer. While these two anti-cancer drugs improve overall survival in women with breast cancer, they increase the risk of developing heart failure. Several randomized controlled trials have demonstrated that sodium-glucose co-transporter 2 (SGLT2) inhibitors, including Empagliflozin (EMPA), which is a novel anti-diabetic medication, reduce the risk of heart failure associated hospitalization and mortality in patients with and without diabetes. Little is known, however, about whether SGLT2 inhibitors are cardioprotective in the setting of chemotherapy mediated cardiotoxicity.
Objective: The specific aim of this thesis is to evaluate whether the prophylactic use of SGLT2 inhibition with EMPA will be comparable and/or synergistic to standard pharmacological therapy using the renin-angiotensin system (RAS) antagonist perindopril (PER) in preventing DOX+TRZ mediated cardiotoxicity in a chronic in vivo female murine model.
Methods: In a chronic in vivo murine model of chemotherapy mediated cardiotoxicity, a total of 160 C57Bl/6 female mice received prophylactic treatment with PER (3 mg/kg), EMPA (10 mg/kg), or EMPA+PER orally for a total of 3 weeks as a run-in period prior to weekly administration of DOX+TRZ (8 mg/kg and 3 mg/kg, respectively) intraperitoneally for an additional 3 weeks (total of 6 weeks). Serial echocardiography was performed on a weekly basis and at the end of week 6, cardiac tissue was collected for histological, biochemical, and lipidomic analyses.
Results: In mice treated with DOX+TRZ, the left ventricular ejection fraction (LVEF) decreased from 75±3% at baseline to 41±4% at week 6. Prophylactic treatment with either PER, EMPA, or EMPA+PER improved LVEF to 57±3%, 66±3%, and 68±4% at week 6, respectively (p<0.05). Histological analyses confirmed significant disruption of myofibrils, vacuolization, and loss of sarcomere integrity in the DOX+TRZ treated mice. Prophylactic administration with PER, EMPA, or EMPA+PER, however, improved myofibril integrity at week 6 in mice receiving DOX+TRZ. Additionally, the Bax/Bcl-xL ratio was significantly elevated by 1.5x fold in mice receiving DOX+TRZ. This marker of apoptosis was attenuated by prophylactic treatment with either PER, EMPA, or EMPA+PER, to a level comparable with control mice. Finally, in DOX+TRZ treated mice, an increase in two oxidized phosphatidylethanolamine (OxPE) species was observed. Preliminary data demonstrates there is a possible trend in which prophylactic treatment with EMPA+PER attenuates these markers of lipid oxidation.
Conclusion: In a chronic in vivo murine model of DOX+TRZ induced cardiotoxicity, the prophylactic administration of PER, EMPA or EMPA+PER was effective in preventing adverse cardiovascular remodeling, attenuating histopathological changes in cardiomyocyte structure, and improving markers of oxidative stress and apoptosis.2023-2024 Research Manitoba-CancerCare Manitoba Masters Studentship AwardOctober 202
The association and differences of various lower body athletic performance metrics in adolescent male football and volleyball athletes
No full textThe countermovement vertical jump (CMVJ) is considered a primary indicator of lower body muscular power producing capability and has strong positive relationships with field and court sport performance. Performance in the CMVJ is influenced by multiple physiological and anthropometric factors. The aim of this study was to examine the relationships between CMVJ height, peak lower body force production (Fmax), resisted sled sprint power output (RSS) and fat free body mass (FFM) among male football (FB) and volleyball (VB) players aged 16-18. The study (n=68) included two participant groups (FB group n=33, VB group n=35) all being assessed on CMVJ height (cm), lower body Fmax (N) via isometric back squat test, peak power production (W) via RSS, and FFM (kg) via bioelectric impedance analysis. Participants groups were examined for significant between-group differences with an independent t-test while Pearson product moment correlations between CMVJ height, Fmax (N, N/kg, and N/kg FFM), RSS (W, W/kg, and W/kg FFM) and FFM were calculated. FB group means for body mass and FFM (87.02 17.02 kg; 68.27 8.61 kg, respectively) were significantly higher (p 0.05). The results of this study suggest that relative lower body maximal force producing capabilities have a strong, significant correlation with CMVJ performance among FB and VB athletes. Further, findings suggest that relative Fmax scores by FFM in lieu of body mass does not strengthen the relationship with CMVJ height.October 202
Assessing water quality governance in Manitoba
No full textThis thesis investigates the persistent governance challenges related to nutrient pollution and eutrophication in Manitoba, emphasizing phosphorus and nitrogen management. Despite decades of policy initiatives aimed at curbing nutrient pollution, eutrophication remains a significant environmental concern. Through qualitative methods such as key-informant interviews, document analysis, and policy reviews, the research examines how governance structures—including regulatory frameworks, voluntary programs, and participatory mechanisms affect nutrient management outcomes.
The first manuscript identifies persistent epistemic, social, and political controversies underpinning Manitoba’s nutrient governance, particularly around problem definition, policy tools, and scientific credibility. Drawing from Science and Technology Studies (STS), the research highlights that these disputes reflect deeper power dynamics and social-political tensions, especially involving agricultural and industry actors. While Indigenous rights and governance are acknowledged as important, this manuscript notes they are not the central focus due to data and scope limitations.
The second manuscript critically evaluates Manitoba's "hybrid" governance regime, which combines mandatory regulations and incentive-based voluntary approaches. It finds that, despite encouraging innovation and stakeholder engagement, the regime has not significantly reduced nutrient loading to Lake Winnipeg. Key barriers identified include weak enforcement, limited monitoring, resistance from agricultural actors, and insufficient support for marginalized groups such as Indigenous and small-scale farmers. The manuscript argues that successful governance must address underlying issues of power, knowledge hierarchies, and justice.
Overall, the thesis concludes that Manitoba’s nutrient management issues extend beyond technical inadequacies, deeply rooted in persistent controversies, power asymmetries, and contested knowledge production. Effective governance therefore requires adaptive, inclusive, and justice-focused approaches. Strengthening genuine collaboration among government bodies, agricultural producers, environmental organizations, and Indigenous nations is essential. Enhanced monitoring and transparent enforcement mechanisms, participatory adaptive management, and targeted support for marginalized producers are crucial. Additionally, embedding controversy analysis and adaptive learning within governance structures transforms persistent disputes into opportunities for ongoing policy improvement, offering globally relevant insights for sustainable watershed governance.October 202
Development and application of methods using oxylipins to examine dietary omega-3 requirements and phospholipase A2 activity
No full textOxylipins are bioactive lipid mediators formed from polyunsaturated fatty acids (PUFA) that are released from membrane phospholipids by phospholipase A2 (PLA2). Since oxylipins mediate PUFA effects, methods using oxylipins were developed to answer key questions in lipid nutrition and metabolism. First, docosahexaenoic acid (DHA), arachidonic acid (ARA) and their derived oxylipins in serum, liver and kidney of male rats, and male and female mice that received graded doses of α-linolenic acid (ALA) were analyzed by mass spectrometry. DHA/ARA oxylipin and fatty acid ratios were then used to demonstrate that the dietary ALA requirement in growing rodents is 0.55g ALA/100g diet, which is higher than that provided by standard laboratory rodent diets. Second, this new method was applied to serum, liver, heart and brain of weanling male and female rats in response to graded doses of dietary ALA and DHA to elucidate that 0.12g DHA/100g diet is bioequivalent to the ALA requirement of 0.55g ALA/100g diet. Third, use of inhibitors to assess ex vivo PLA2 activity towards PUFA and oxylipins in rat hearts revealed calcium-independent (i)PLA2 had activity towards all PUFA and oxylipins analyzed, while secreted (s)PLA2 had greater specificity towards DHA and its oxylipins. The oxylipin data generated may help explain the failure of sPLA2 inhibitor drugs for cardiovascular disease. Fourth, application of this new method in weanling male and female rats showed that dietary DHA increased iPLA2 and sPLA2 activity towards DHA and its oxylipins, whereas dietary ALA increased activity towards ALA, ARA and their oxylipins. iPLA2 and sPLA2 activity towards PUFA was higher in females. In contrast, male hearts had higher cyclooxygenase-derived ARA oxylipin formation, which was attenuated by dietary DHA. In conclusion, the dietary ALA requirement in growing rodents was estimated to be 0.55g ALA/100g diet, and DHA was ~5-times more potent than ALA, with a bioequivalence of 0.12g DHA/100g diet. Further, the findings herein advance the understanding of how different PLA2 enzymes contribute to diet and sex effects on oxylipins. These findings have implications for potential reformulation of standard rodent diets, and for development of sex-specific dietary omega-3 PUFA guidelines and drugs for cardiovascular health.Natural Sciences and Engineering Research Council of Canada [RGPIN-06215-2020];
Government of Manitoba [Manitoba Graduate Scholarship] and the University of Manitoba [GETS]October 202
The Kerzman-Stein operator on Smirnov space and an analogue for Dirichlet space
No full textWhen defined on the space of a smooth Jordan curve in , the skew-adjoint part of the Cauchy integral operator , called the Kerzman-Stein operator, is notable both for its compactness and role in the Kerzman-Stein formula relating to the Szeg\H o projection . We investigate various identities and properties of the Kerzman-Stein operator on the Smirnov space of harmonic half-order differentials, as well as introduce a natural analogue of the operator for the homogeneous Dirichlet space of harmonic functions, and show that it is related to the Grunsky operator.
Working over Ahlfors-regular Jordan domains in the Smirnov setting, we derive adjoint formulas for the Cauchy operators that allow us to generalize the Kerzman-Stein formula to this new analytic setting. Further, we provide sufficient curve conditions for the Kerzman-Stein operator to belong to the Schatten -classes for all . An extension of is also considered, which is an isomorphic map between the spaces on the complementary components of the curve. This mapping is related to through overfare, and has the property of being unitary precisely for disks. Alongside this, we show that the Smirnov space Grunsky operator recently introduced by Kristel et al. (2025) is in the Schatten class precisely when is in . As a consequence of this new perspective, we apply our results to show that all Jordan curves are Weil-Petersson class quasicircles.
Adjacent to this is our work in the Dirichlet space setting, where we define an analogue of , which we denote , that shares many similar properties as its Smirnov space counterpart. In particular, we show that a Kerzman-Stein formula with holds for quasicircles, and we compute identities which closely relate these operators with overfare. From here, we show that the (classical) Grunsky operator is in if and only if is in . In particular, the independent results of Jones (1999), Takhtajan and Teo (2006), and Shen (2007) imply that Hilbert-Schmidtness of is met precisely for Weil-Petersson class quasidisks.October 202
Evaluating the effectiveness of overwintering cover crops in supporting spring soil trafficability in Manitoba
No full textExcess soil water is typical of soils in Manitoba during the early growing season due to snowmelt and heavy rainfall. Managing soil water to attain optimal soil strength for soil trafficability is therefore crucial to ensure timely field operations in the region. Over the years, subsurface drainage has been the most popular approach for the removal of excess soil water. However, this approach is not always feasible due to poor internal drainage and/or compromised soil structure. This study evaluated whether a fall shoulder cover crop could improve spring trafficability. We leveraged a multi-year experiment initiated in fall 2020 near Cartwright, MB (Farming Systems Lab). From fall 2022, fall rye (Secale cereale) has been grown to assess effects on soil water dynamics and the resulting soil strength relative to a no-cover control. The trafficability criterion was volumetric water content ≤ 90% of the lower plastic limit in the 0 – 25 cm layer. Across the monitoring period, measured water contents in both treatments commonly exceeded this threshold; consequently, fall rye did not support trafficability. A 2015–2023 climate analysis for Cartwright and comparative regions in Northwest and Eastern Manitoba showed that fall conditions seldom supported successful rye establishment: neither four consecutive weeks with mean daily temperature ≥10 °C nor the accumulation of 309 growing degree days before cold hardening were achieved. As a result, rye produced insufficient biomass to meaningfully increase evapotranspiration.
HYDRUS model simulations indicated that delaying termination to June 20 could create brief windows, up to 21 days, where soil moisture met the trafficability threshold; however, these windows were highly vulnerable to rewetting from subsequent rainfall events.
Overall, fall rye as a standalone strategy was not effective for managing excess soil water under these conditions. These findings highlight the limitations of fall rye as a standalone strategy for managing excess soil water in Manitoba and emphasize the need for integrated approaches to improve trafficability under challenging soil and climatic conditions.Manitoba Crop Alliance, Manitoba Canola Growers Association, Manitoba Pulse and Soybean Growers, and Sustainable Canadian Agricultural PartnershipOctober 202