30921 research outputs found
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Sourcing of microplastics entering Lake Winnipeg, Manitoba, Canada
No full textThe accumulation of plastic pollution is a pressing issue, especially the presence of microplastics in the environment. Microplastics are ubiquitous in the environment, however a research gap exists in understanding the sources of microplastics in freshwater environments. The lack of standardized methodologies for the collection, quantification, and identification of microplastics hinders our understanding of the sources and amounts of microplastics in the environment. This thesis evaluates the potential of carbon and hydrogen stable isotope (δ13C and δ2H) and elemental (%C and %H) analysis to identify the polymer type of microplastics. The polymer type of microplastics provides important information on their source. Commercial plastic products (n = 53) from six different polymer types were used to create a database of characteristic δ13C, δ2H, %C, and %H values for each polymer type. Environmental microplastics (n = 18) of unknown polymer types were also analyzed and their values were compared to the characteristic values for each polymer type in the database. Fourier transform infrared spectroscopy was used to confirm the identification of the polymer type of the unknown microplastics. The combination of the δ2H and %H values was best able to distinguish the different polymer types and was most useful for identifying the unknown microplastics. The identification of the unknown microplastics using their δ2H and %H values correlated strongly with identifications using FTIR, confirming that this represents a novel method that can be used to identify the polymer type of microplastics. Because it is a quantitative analysis, it is more attractive than other qualitative methods of identifying the polymer type of microplastics. Additionally, this thesis investigates spatial and temporal trends in microplastic concentrations in the Red River in Manitoba. Surface water samples were collected from nine sites in the spring, summer, and fall of 2022 to evaluate spatial and temporal trends in microplastic concentrations. Microplastics were found in all samples, with concentrations ranging from 70.0 to 268.7 particles m-3. Increased flow rates and stormwater runoff in the spring likely influenced seasonal variations observed in microplastic concentrations. Stormwater runoff, combined sewage overflows, and agricultural runoff are potential sources of microplastics to the Red River.October 202
The impact of supervised consumption sites on acute care health services: A literature review
No full textPeople who use illicit drugs (PWUD) have higher rates of health care utilization
compared to the general population. Additionally, PWUD are more than four times as
likely to leave hospital against medical advice, contributing to costly readmissions for
incompletely treated medical issues. Addressing this issue and providing efficacious care
to PWUD requires the integration of adequate harm reduction strategies in the
community and in acute care facilities. Supervised consumption sites are legally
sanctioned facilities with trained staff that supervise the use of pre-obtained drugs and
provide clean and safe drug equipment to PWUD. The aim of these sites is to prevent
accidental overdose and reduce the spread of infectious diseases, while providing a safe
environment and community for PWUD to have access to addictions resources, health
services and other social supports. The purpose of this literature review is to identify the
degree to which supervised consumption sites can impact health care utilization amongst
PWUD. Specifically, this review aims to identify the impact that community-based SCS
have on overdose-related ambulance attendance, emergency department visits, and
hospitalization, as well as the impact that hospital-based SCS have on reducing patientdirected
discharges for PWUD and contributing to medical retention of patients. This
literature review identifies that the implementation of community-based SCS
significantly reduces the use of emergency medical services for PWUD and is associated
with decreased healthcare costs. The literature identifies a clear demand for access to
SCS for hospitalized PWUD, however more research is needed to understand the efficacy
of hospital-based SCS at reducing harm and decreasing the rates of patient-directed
discharge and costly readmissions in this population
Gender-based violence among adolescent girls and young women: conceptualization and measurement to inform public health programs in low and middle-income countries
No full textAdolescent girls and young women (AGYW), particularly those engaged in transactional sex (TS) and sex work (SW), experience disproportionate rates of gender-based violence (GBV). While public health scholarship and practice acknowledge that GBV may render an individual more susceptible to adverse health outcomes, this understanding often conceptualizes experiences of GBV at the individual as opposed to the structural levels where risk and vulnerability are often shaped. This study aimed to identify whether any gaps exist in how the structural drivers of GBV are both examined and addressed in public health research and prevention programming. Using Relational Gender Theory and the Ecological Framework of Violence to position gender as a multidimensional structure, an integrative review of 31 peer-reviewed articles on GBV interventions in HIV prevention programs targeting AGYW in low- and middle-income countries was conducted. Results revealed a predominant focus on sexual and physical violence perpetrated by partners, with limited attention to emotional and economic forms in approaches to defining and measuring GBV. Interventions primarily targeted individual-level factors, neglecting broader community and structural drivers. A secondary quantitative analysis of existing data examined the association between sex activity typology and GBV among cisgender AGYW engaged in casual sex (CS), TS, and SW in Dnipro, Ukraine. Nearly a quarter of the sample reported experiences of lifetime GBV (24.3%). SW participants had the highest rates of lifetime and recent experiences of GBV, followed by TS and CS participants. After adjusting for confounders, TS participants were 1.8 times (95% CI: 1.3 to 2.5, p < 0.001) more likely to experience lifetime GBV than CS participants, while SW participants were 3.9 times (95% CI: 2.9 to 5.3, p < 0.001) more likely. By applying a robust gendered lens, this project uncovered an opportunity to broaden both the conceptualization and operationalization of GBV within HIV prevention programming and research. Examining experiences of GBV among AGYW in Dnipro, Ukraine reiterated the disproportionate burden of GBV these populations face, particularly those engaged in SW. To effectively address GBV, public health discourse needs to move towards critically engaging with how GBV and power operate across the broader structural context.May 202
Postbiotic strategies alleviate negative effects of subacute ruminal acidosis (SARA) on digestive and immune health in lactating dairy cows
No full textHigh-energy diets feeding in dairy farms can impact the homeostasis of gastrointestinal tract via changing the ecology of gut microbiota and their metabolites thus affecting the functionality of gut epithelium and host immune response, as a consequence, induce metabolic disorders in the body such as subacute ruminal acidosis (SARA). These disorders cause the changes in the fatty acid profile of the milk, affecting the welfare of dairy cows by increasing the incidence of infectious diseases such as systemic inflammation. Therefore, it is critical to find efficient solutions that optimize animal production without compromising gut health. It has been reported that Saccharomyces cerevisiae fermentation products (SCFP) as one of the postbiotics benefits rumen fermentation and overall performance in lactating dairy cows. However, cows respond differently to SCFP among studies. We speculate that this might be due to the fact that the mode of action of SCFP is not completely understood and as such the recommended dose of SCFP for each animal is not optimized.
In this study, we conducted two grain-based SARA challenges in early lactation of dairy cows. We found grain-based SARA challenges increases the lipopolysaccharides (LPS) concentrations in the rumen and hindgut, the concentrations of acute phase proteins and pro-inflammatory cytokines in peripheral blood. Grain-based SARA reduces the richness and diversity of rumen liquid and solid microbiota, alters its taxonomic compositions and predicted carbohydrates and nitrogen metabolic pathways. Besides, grain-based SARA reduces the number of significant associations among different taxa, the diversity of hub taxa in microbial co-occurrence networks in rumen liquid and solid microbiota. We also investigated the possible benefit of two different SCFP (XPC, NutriTek) and the doses effect of NutriTek on immunity status and response, composition and functionality of microbial communities in the rumen and on to grain-based SARA challenges in lactating dairy cows. Our results showed that NutriTek with higher dose (38 g/d) helps to reduce pro-inflammatory status, improve the diversity and richness of the rumen liquid microbiota, promote the growth of cellulolytic bacteria in both rumen liquid and solid microbial communities, hence, attenuating adverse digestive and inflammatory responses associated with grain-based SARA challenges.Dairy Farmers of Manitoba
Diamond VFebruary 202
An experimental study of bedload transport in partially ice-covered channels
No full textThe onset of winter in cold climates often leads to the formation of border ice along riverbanks, a phenomenon that can persist for a significant portion of the winter season, thereby affecting river channels' dynamics and geomorphological structure. Understanding the effects of ice cover on sediment transport and bed morphology is crucial, as these elements significantly influence flow resistance and river behavior. While there is extensive literature on sediment transport and bed morphology in open channel flow and several studies in conditions of complete ice cover, research in partially ice-covered channels is sparse.
To address this gap, the current study conducted laboratory experiments at the Hydraulics Research and Testing Facility at the University of Manitoba, Canada. The research aimed to explore the effects of border ice, including the extent of ice cover, variations in flow strength, and the asymmetry of border ice on bedload transport rate and distribution, as well as bed morphology and bedform characteristics. Various experimental setups, ranging from open channel flows to symmetric and asymmetric border ice and fully ice-covered conditions, were analyzed to assess bedform dimensions and bedload transport rates against theoretical models in the literature. This comparison confirmed the reliability of the models in describing bedform features under varying ice conditions. Moreover, despite noticeable differences in bedload transport rates across the channel width, in partially ice-covered conditions, the cross-section-averaged bedload transport rate could still be accurately estimated using conventional equations adapted for open channel and fully ice-covered flows by adjusting for the additional boundary created by the ice in the calculation of the wetted perimeter.
The findings also demonstrate that the presence, positioning, and varying extents of partial ice cover significantly influence bedforms within the channel and the distribution of bedload transport. Notably, the impact of ice coverage is more pronounced at lower flow strengths and diminishes as flow strength increases. This research provides essential insights into the complex interactions between ice cover and sediment transport.October 202
Assessing the impact of grazing on nutrient export from pastureland in an ungauged basin in Manitoba under climate change using an integrated modelling approach
No full textAssessments of climate change impacts on hydrology and nutrient export from pasturelands are not readily available in Canada. The objective of this study was to implement an integrated modelling approach to predict the impact of climate change on the hydrology and nutrient fluxes on a 46.6 km2 pasture-dominated ungauged watershed in Manitoba. The Integrated Farm System Model (IFSM) was used to predict the pasture yield/residues, and manure production. To simulate the hydrological response, the Cold Regions Hydrological Model (CRHM) platform and the Hydrological Predictions for the Environment (HYPE) model were used. Predictions of nutrient exports to stream were also carried out using the HYPE model. Model assessments were conducted for the historical reference period between 2000 and 2019, and for the near (2020 – 2049) and the distant future (2050 - 2079) periods using climate projections under two Representative Concentration Pathways (RCP). Satisfactory model performance was obtained for the three individual models using available observations. Under a changing climate, pasture yields were anticipated to decrease by approximately 2% to 6.8%, with an exception that a 2% increase in pasture yield was predicted in the near future period under RCP 4.5. There was no significant changes observed in manure production. Both CRHM and HYPE models predicted a 20% and 40% reduction in stream discharge in the near future under RCP 4.5, respectively. Meanwhile, CRHM predicted an increase in stream discharge by 26% and 39% in the near future and distant future periods under RCP 8.5. In contrast, HYPE had a marginal increase in stream discharge, averaging 2% under RCP 8.5. An earlier onset of spring snowmelt was predicted by both CRHM and HYPE, ranging from 6 to 21 days in future periods compared to the reference period, implying a potentially longer growing season. Lastly, a 33% and 4.5% reduction was observed in the projected total nitrogen load in future periods under RCP 4.5 and RCP 8.5, respectively. The total phosphorus loads, on the other hand, had a significant average reduction of 50% and 35% under RCP 4.5 and RCP 8.5, respectively. It was found that the general pattern of nutrient export (N and P) closely mirrored that of the stream discharge. Overall, the predicted reduction in nutrient export implied a lower risk of eutrophication in the study area.Manitoba Beef ProducersFebruary 202
Optical particle analysis for use in simultaneous high throughput flow cytometry
No full textMany methods of single-cell analysis are currently used, and each method provides different characteristics of the cell, such as dielectric and physical properties. In this thesis we investigate the use of optical analysis in tandem with dielectrophoresis analysis in a high throughput flow cytometer system.
To examine the viability of combining optical and dielectrophoretic analysis methods, this thesis proposes an optical model using Mie scattering theory, and a data extraction and particle classification algorithm that employs both analysis modalities. The optical model presented here examines the effects of different experimental variables such as particle size and refractive index, the refractive index of the medium, and cytometer components like LED wavelength. The data extraction and particle classification algorithm presented extracts both optical and DEP data and is used to identify and sort particles in mixed population experiments. Combining the information gathered from examining the optical data from particles as well as the dielectric properties from dielectrophoretic measurements provides a more robust and confident classification of particles.
In this thesis, the combination of the two methods was applied to both polystyrene polymer sphere (PSS) beads and Chinese hamster ovary (CHO) cell experiments. Particle size data was successfully extracted using optical analysis and used to provide more confidence and robustness to the particle classification conducted using DEP analysis. The findings of this thesis provide a starting point for further use of optical analysis in conjunction with DEP analysis in a high through put flow cytometer system.May 202
Investigating the therapeutic effects of simvastatin on a mouse model of Rett syndrome
No full textRett syndrome (RTT) is a progressive neurodevelopmental disorder without an available cure. It is a rare disease but is known as one of the most common causes of intellectual disabilities and motor dysfunction in females. Approximately 90-95% of RTT cases result from loss-of-function mutations in the X-linked gene called the Methyl-CpG binding protein 2 (MECP2). MeCP2-T158M is the most common missense mutation found in patients, accounting for about 12% of RTT cases. Interestingly, it was reported that increasing MeCP2-T158M expression improved RTT-like phenotypes in both T158M male and female mice in vivo. For over ten years, researchers have been interested in statins, a family of drugs used to lower plasma LDL-cholesterol, as a potential treatment for RTT due to impaired cholesterol metabolism associated with the syndrome. In the statin family, simvastatin has the highest lipophilicity and can effectively cross the blood-brain barrier to enhance its bioavailability in the brain. Therefore, in this research thesis, I hypothesize that increased translation caused by simvastatin will increase the levels of MeCP2 and MeCP2E1 in the brain of Mecp2T158M/y mice and rescue altered levels of other RTT-related proteins. Additionally, simvastatin improves RTT-like phenotypes in Mecp2T158M/y mice. I address my hypotheses through two research aims: determine the molecular effects of simvastatin at the protein level in a brain-region-dependent manner and examine the therapeutic effects of simvastatin on RTT-like phenotypes in the Mecp2T158M/y mouse model. The results showed that at the protein level, simvastatin significantly increased the levels of pS6 Ser235/236 and pS6 Ser240/244 in the cerebral cortex of T158M male mice, suggesting the molecular effects of simvastatin on increasing translation. Furthermore, preliminary data revealed a trend of improving RTT-like phenotypes in a dose-dependent manner with simvastatin treatment. Nevertheless, simvastatin did not rescue reduced levels of MeCP2 and MeCP2E1 in the brain of T158M male mice and altered levels of other RTT-related proteins such as SNAP25, PSD95 and Tau. Unexpectedly, simvastatin treatment may cause unexpected neuronal cell death. Collectively, further studies are needed to address the molecular impacts of simvastatin in the brain and the phenotypic outcomes at different doses.May 202
Investigation of building virtual worlds with spatial design domain experts
No full textThe popularity of immersive web virtual worlds has increased as a result of the pandemic. Platforms like Gather, that still sees more than a million visitors quarterly post-pandemic, combined real-time video conferencing functionality with virtual worlds: multi-user virtual environments that function as virtual offices or social spaces. This combination has not only incorporated interactivity and engagement in the videoconferencing space but has also brought the capability of virtual world
building to the masses, including to people without programming backgrounds. My research investigates the tools used for virtual world building, which are feature-rich
creativity support tools. Given their availability, I want to understand how easy it is for non-programmers to use virtual world building tools to build virtual worlds,
or more specifically, what the limitations of these virtual world building tools are by having users with backgrounds designing physical world spaces (such as architecture
and interior design students) build virtual spaces. In this research, I investigate the technical challenges and creative limitations that such users experience, and how they
troubleshoot their virtual world designs. The results show that participants are able to produce interesting virtual worlds with 2D virtual world authoring tools. However, advanced features appear to be too complicated to use consistently. This led to users sticking to basic features that they are familiar with. Additionally, users
did not appear to test and debug their work frequently, if not at all. Based on these findings, I explain in what way these virtual world authoring tools frustrate users
and produce design suggestions to improve creativity support for them. This thesis contributes results from the user study of non-programmer use of 2D virtual world authoring tools, provides evidence of user difficulty with juggling multiple toolchains and design suggestions to improve virtual world authoring experiences to democratize this digital craft.October 202
Unravelling the seams: text(ile)s of compassionate un/settling
No full textIn this performative inquiry, I stitch my own experiences of un/settling in an educational context together with an art-ful practice of contemplative quiltmaking. This study is in response to the Truth and Reconciliation Commission of Canada’s Calls to Action for education. Through performative inquiry, I take moments that call my attention—un/settling moments—to the fabric and ask, “What do I need to know, right here, right now?” What happens when a teacher/a community member/a family member unmakes/unsettles/unlearns with a quilt in her hands? What does she learn about unsettling? Throughout the inquiry, care is taken to centre compassionate landscapes of knowing, being, and becoming, in the making of quilts, research inquiry, and texts that communicate knowledge and knowing. A significant aspect of the study is its context; a small, rural, farming, town in the Canadian prairies settled in the early 1870s. I draw on autoethnography to understand un/settling moments in relation to culture, society, and family. Readers are invited to read a thesis, unconventional in form and style; an embodied step towards un/settling.February 202