14277 research outputs found
Sort by
QED corrections at next-to-leading order and next-to-next-to-leading order
No full textThis thesis focuses on higher-order quantum electrodynamic (QED) and electroweak
radiative corrections, essential for precision in high-energy physics experiments. The
leading-order radiative corrections to the Bethe-Heitler process (γ + p → l+l− + p) were
computed using a refined numerical approach, emphasizing corrections from the proton
current. The results show significant contributions of radiative corrections, particularly
in tests of lepton universality.
Additionally, the running of the fine-structure constant α at the two-loop level was studied
using a dispersive approach. The methodology addresses challenges in evaluating
multi-loop Feynman diagrams by introducing dispersive propagators and sub-loop insertions.
Calculations were performed for sunset and triangle topologies, thereby enhancing
the accuracy of theoretical predictions in QED and providing improvements in precision
testing of the Standard Model. This research underscores the importance of high-order
corrections in theoretical models and their role in identifying possible new physics beyond
the Standard Model
Petrology, geochemistry, and geochronology of the root N’ cellar low sulfidation epithermal prospect in Newfoundland, Canada
No full textThe Root N’ Cellar Au-Ag-Te epithermal occurrence (RNC), located on the Burin Peninsula of Newfoundland, Canada, is an incredibly well-preserved Neoproterozoic volcanic system. The RNC is hosted within the Avalon Terrane in Newfoundland, which represents the easternmost extent of the Canadian segment of the Appalachian Orogen in Newfoundland. The host rocks of the prospect area consists of dominantly mafic, chemically bimodal sequence (basaltic andesite – rhyodacite) of flows and volcaniclastic rocks with common alteration assemblages including a proximal SiO₂ + K-rich sericite (illite) + adularia, and a more distal propylitic (epidote + carbonate + chlorite) assemblage.
The rhyodacites at the RNC have been dated at 578 – 574 Ma, coinciding with the main period of Avalonian arc magmatism, and consistent with the known age of the Marystown Group. Petrology, geochemistry and geochronology indicate that the RNC likely formed in an arc-adjacent, intra-arc, or back arc basin tectonic environment.
Analysis of alteration induced geochemical patterns from an assay database details alteration assemblages and mass balance chemistry changes indicative of formation from near-neutral pH reduced fluids, typical of low sulfidation epithermal systems. Furthermore, the preservation of geochemical trends suggest that the Discovery Trench to have seen hydrothermal fluid conditions similar to those associated with central to upper portions of a geothermal upflow zone
ICU standards and safety resource
No full textBackground: Intensive Care Units (ICUs) are high-risk settings where variation in bedside
safety practices and routine care practices may contribute to adverse events, including line
dislodgements and documentation errors, and the risk of infection. Staff working in the Foothills
Medical Centre ICU identified a gap in portable, consolidated resources that could better support
the consistency of bedside safety and shift practices. Purpose: The intention of this practicum
was to create a standardized bedside ICU safety resource and education materials to promote
effective staff onboarding and adherence to evidence-based safety practices. Methods: Three
key methods were used to develop the ICU standards and safety resource: 1) an extensive
literature review, 2) consultations with staff nurses, clinical nurse educators, unit managers, and
safety leads, and 3) an environmental scan. Results: Thematic synthesis produced four domains:
(1) infection prevention and clinical outcomes; (2) tool design, usability and leadership; (3)
integration and communication; and (4) staff competency, communication and team culture. The
evidence presented throughout the literature consistently supported the use of structured bedside
safety tools in reducing preventable patient harm, improved coordination of team members,
increased staff confidence in their care delivery, and improvement in possible patient outcomes.
Local consultations revealed that segregated access to resources together with variability in
routine practices serve as barriers to providing safe and consistent patient care. Conclusion: The
standardized bedside ICU safety tool or resource was developed to bridge the gap in care to
improve patient outcomes, improve efficiencies in workflow and support a stronger safety
culture
Modelling and simulation of ice impact loads relevant to non ice strengthened hull forms
No full textMaritime activity in polar waters has been steadily on the rise in recent years, resulting in
increasing interest into the ability of low- and non-ice strengthened ships (NISS) to conduct
limited operations in ice infested regions. Modelling and simulation of ship-ice impact
loads has traditionally focused on scenarios relevant to the design and classification of ships
purpose built for navigation in ice, with assumptions that may not be suitable for the
evaluation of ice loads on NISS. As such, there has been recent research activity aiming to
rectify this, adapting and modifying traditional models as part of the development of safe
speed studies seeking that evaluate NISS in ice.
The present thesis focuses on the application of the Popov-Daley method, the current ice
crushing load model used the International Association of Classification Societies (IACS)
Unified Requirements for Polar Class Ships (Polar URs), to scenarios relevant to NISS.
First, an analytically derived time-history model of a Popov-Daley style ship-ice impact is
developed as a first step towards the modelling of moving loads, which may be a concern
for ice impacts involving NISS that result in a plastic hull structure response. Next, the
frictionless assumption on the ice crushing force from the original Popov-Daley method is
tested for impact scenarios with finite floe sizes more relevant to NISS.
After this, a structural response model of the Ex-HMCS IROQUOIS, taken as a
representative naval hull form, was developed using the Popov-Daley method to model the
ice indentation energies. This model allows for the calculation of the reduced impact force
when considering structural response, calculation of the expected structural indentation
depth, and determination of the expected structural consequence level, ranging from local denting of the hull plate to the buckling of main transverse stiffeners. Lastly, the Ex-HMCS
IROQUOIS was simulated using the computer program GEM in forward transit through a
variety of parametrized ice regimes meant to represent possible environments where NISS
may wish to consider limited operations in exceptional scenarios, such as for search and
rescue (SaR). The previously developed time-history and structural response models were
used to process the GEM data, and an operational capability assessment of the Ex-HMCS
IROQUOIS was completed that evaluates performance of the ship structure in all simulated
conditions
Held together with tape: home recordings, proactive archiving, and memory in English-speaking Gaspé
No full textThis thesis explores the dynamics of memory and forgetting in a proactive archives that prioritizes digitizing, curating, and recirculating music first recorded on domestic analog audio tapes within the English-speaking minority from the easternmost sector of Quebec’s Gaspé Peninsula (Gaspé Bay). Leveraging insights from the broad and interdisciplinary scholarship of social memory, this thesis also seeks to reimagine the role of sound archives in ethnomusicology by proposing an applied methodology that considers slowness as a temporality for engendering more resonant and responsive memory-making during ethnographic fieldwork.
The ethnography considers the researcher’s activities listening to home recordings with community members, appraising personal tape collections, and engaging with community organizations to contemplate and establish archival futures for analog home recordings and digital field recordings. This thesis’ archival and ethnographic work simultaneously document and interpret intersecting realms of twentieth and early-twenty first century musical culture and media practices in this community: The ethnography of listening uses a memory studies perspective to understand the appropriation of popular song repertoires and styles within local practice. The ethnography of tape collecting traces the domestication of reel-to-reel and compact cassette tape recorders by two prolific tape makers, exploring how their personal values and understandings, professional work histories, and gender shaped what was put to tape; how tapes reflected and shaped family and community; and what was eventually digitized and archived during fieldwork. The ethnography of archiving evaluates the institutional and structural potentials and limitations of the applied proactive archival methodology proposed in this thesis
Integrating frailty assessment with geriatrics-led interventions in hospitalized older adults
No full textPopulation aging and frailty pose major challenges for health care delivery. Hospitalized frail older adults face increased risks of health decline and loss of independence. Newfoundland and Labrador, has no systematic approach to frailty assessment or management.
This study evaluated a geriatric specialist-led, multicomponent intervention for frail elderly inpatients versus usual care. Frailty was measured and outcomes compared. Inpatients over age 65 were frailer than previously studied populations (80% CFS>4) and women were frailer than men (mean CFS 5.1 vs 4.7, p<0.001). No statistically significant differences were found between intervention (n=134) and usual care (n=249) groups in the primary outcome (death and/or institutionalization within one year, HR=0.91, p=0.57) or the secondary outcome (Emergency Department representation within one year, HR=0.94, p=0.641). Higher Clinical Frailty Scale scores (6+ vs 4-5) were associated with increased risk of death and/or institutionalization (HR=2.40, p<0.001). Among patients with low Clinical Frailty Scale scores (4-5), higher Frailty Index-Laboratory scores (>0.3) predicted this outcome (HR=2.48, p<0.014).
Although the intervention did not impact selected outcomes, the study demonstrates the feasibility of frailty measurement and its potential role in care pathways. Future initiatives should build on best practices and ensure appropriate system-level support for frailty care implementation
In vitro culture and epigenetic variation in northern berry crop
No full textVaccinium vitis-idaea L., commonly known as lingonberry and also popular as partridgeberry, is a nutrient-rich, antioxidant-packed "superfruit" with immense commercial potential. Native to boreal regions across North America, Eurasia, Alaska, and Canada, lingonberries have long been valued by indigenous communities. Despite their health-promoting properties, large-scale cultivation of lingonberries remains limited due to their woody recalcitrant nature and poor proliferation via traditional or conventional propagation methods. My research explores somatic embryogenesis (SE) as a viable micropropagation strategy for lingonberry. For the first time, a successful SE protocol was established in two lingonberry genotypes using thidiazuron (TDZ) on a semi-solid medium. The role of TDZ in influencing redifferentiation and antioxidant activity was systematically studied. Regenerated plants were not only genetically identical but also demonstrated altered phytochemical profiles, particularly increased levels of flavonoids, anthocyanins, and antioxidants, when compared to their donor plants. To understand the underlying epigenetic mechanisms, global DNA methylation patterns were analyzed using UHPLC-MS/MS, a rapid and highly accurate technique. The in vitro SE-regenerated plants exhibited higher methylation levels compared to the ex vitro plants. Interestingly, even with reduced methylation in ex vitro, the elevated phytochemical levels (of catechin) persisted, suggesting the presence of epigenetic memory or biological imprint. To validate this observation, enzymatic methyl sequencing (EM-Methyl seq), a more precise alternative to bisulfite sequencing, was applied for the first time in lingonberry to confirm methylation pattern changes in CpG, CHG and CHH sites. The final chapter addresses hyperhydricity, a frequent physiological disorder in tissue culture, by identifying its anatomical, morphological, biochemical indicators and proposing mitigation strategies. Gene expression analysis was conducted to identify the genetic basis of hyperhydricity, focusing on which genes are responsible for its onset and how their expression patterns differ between hyperhydric and non-hyperhydric shoots. The study also examined how beneficial genes, such as those involved in antioxidant activity and defense responses, become upregulated under hyperhydric conditions. Insights from this analysis contribute to understanding how hyperhydricity can be mitigated using potassium silicate, with the aim of promoting recovery and restoring normal physiological function in hyperhydric shoots. Together, these findings enhance the understanding of in vitro culture, regeneration, and epigenetic stability in lingonberry, advancing its potential as a sustainable, high-value crop for agriculture, nutrition, and human health
Propeller-induced hull pressure measurement accuracy in tow-tank tests: a methodology for mitigating structural dynamics effects
No full textShip design has to include a comprehensive consideration of onboard vibrations, which is crucial for ensuring passenger comfort and safeguarding machinery and structural integrity. Marine propellers are significant sources of these vibrations, and studying propeller-induced hull pressures (PIHPs) is important in early design phases to mitigate excessive hull and shaft vibrations. Full-scale measurements of propeller-induced pressures (PIPs) are expensive and can only happen once a ship is built and operating, leading to the use of model-scale towing tests as the most effective methodology to assess PIHP in ship design. PIHPs are measured during model tests by a set of flush-mounted pressure transducers at the model stern. While performing the tests, PIHPs excite the model's structures, whose resulting vibrations can affect the accuracy of the measured data. Concerns about the impact of these vibrations on pressure measurements have been raised by ITTC cavitation committees across several conferences. This research aims to address the ITTC concerns by presenting a novel methodology to enhance the precision of PIP measurements and address the model structural dynamics. The presented methodology is based on a combination of experimental tests and numerical simulations. Self-Propulsion (SP), Bollard Pull (BP), and resistance tests were performed at the tow tank of the Ocean, Coastal, and River Engineering Research Centre of the National Research Council of Canada. These tests were combined with the Operational Deflection Shape (ODS) analysis of the ship model. A simplified Finite Element (FE) model of the scaled ship's complex structure was developed and updated using Latin Hypercube Sampling (LHS) and Response Surface Methodology (RSM) against results from Experimental Modal Analysis (EMA) tests. The added mass effect of the surrounding water was taken into account by employing a fully coupled Fluid-Structural Interaction (FSI) approach, combining Finite Element and Boundary Element methods (FE-BE). The validated FE model was used to evaluate the model's structural Vibration-Induced Pressures (VIP) using harmonic acoustic analysis. These results were then used to evaluate the impact of the model's structural dynamics on the measured PIHPs. Finally, the implementation of the proposed methodology to develop a simplified tool to predict PIHPs for different propellers' design parameters is discussed. This thesis presents a novel methodology to quantify and mitigate the effect of model structural vibrations on the accuracy of model scale propeller-induced pressures
Decline in the running performances of lower-ranking participants in popular road races.
No full textNumerous studies have reported a decline in cardiorespiratory fitness (CRF) over recent decades. This study investigates whether long-term trends in running performance reflect this broader reduction in aerobic capacity. By analyzing race results across performance percentiles (90th, 50th, and 10th), the research explores how changes in endurance capacity may differ across competitive levels. Using data from the major road race Tely 10, spanning 1995 to 2020, this study examines temporal changes in running speed and estimates predicted VO₂ max as an indicator of CRF. The analysis provides valuable correlational evidence that endurance performance patterns correspond with well-documented reductions in aerobic fitness over time.
The data for this study was collected through web scraping, utilizing publicly accessible information from the Tely 10 race. This method allowed for the extraction of relevant performance data over time, enabling an analysis of trends in running performance in relation to the decline in cardiorespiratory fitness (CRF).
The statistical analysis using ANOVA and post-hoc Tukey's test reveals a significant decline in VO₂ max values among lower-ranking participants over the years. The data shows notable decreases in performance for these participants, indicating a broader trend of cardiorespiratory decline within the general population, which negatively impacts their running performance over time.
The one-way ANOVA for both the 10th percentile and Trained runners revealed a decline in performance across decade groups. The analysis showed a high R² value of .862, suggesting a CRF decline over time
Reverse vaccinology and pathogenesis of marine bacterial pathogens in lumpfish (cyclopterus lumpus)
No full textLumpfish (Cyclopterus lumpus) are increasingly valued within the aquaculture industry for their role as cleaner fish in salmon farms, where they help control sea lice infestations. However, their effectiveness and survival are compromised by bacterial pathogens including Piscirickettsia salmonis, Aeromonas salmonicida, Yersinia ruckeri, Vibrio anguillarum, and Moritella viscosa, which pose significant health risks and can lead to high mortality rates. Effective management and control of these bacterial diseases are crucial for maintaining the health of lumpfish and the overall sustainability of aquaculture operations. This thesis explores reverse vaccinology as an innovative approach to combat these bacterial threats. Comprehensive genomic and proteomic analyses were utilized to strategically identify antigens capable of triggering robust immune responses in lumpfish. Several bioinformatics tools were used to select potential epitopes derived from common toxins and virulence factors of bacterial pathogens to construct a Multi-Epitope Chimeric Vaccine (MCV) in-silico. Computational analysis confirmed MCV's structural stability, and immune simulation suggested that MCV could elicit strong B-cell and T-cell responses, promoting both humoral and cell-mediated immunity. The immune response of lumpfish to adjuvants was evaluated. Also, the efficacy of the MCV was evaluated in lumpfish. Clinical signs, histology, survival rates, bacterial load, and immune response were determined. The results revealed significant immunogenicity to the MCV, evidenced by high antibody titers at 4 and 6 weeks post-vaccination compared to controls (p ≤ 0.05, p ≤ 0.01). The co-infection lumpfish model and the single infection model were utilized to challenge the MCV. Vaccinated lumpfish were challenged with V. anguillarum and/or A. salmonicida or P. salmonis. Mortality was delayed in vaccinated animals. This study provides critical insights into the development and application of multiepitope vaccines in aquaculture