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Reconceptualizing Internationally Educated Nurses’ Transitions into ICU
No full textDespite decades of research and resources dedicated to understanding and supporting the transitions of IENs into US workplaces, transitions are reported to remain challenging for IENs. Reported challenges include the use of technologies, struggles with differences in nursing practice and role variations, and discrimination. These ongoing challenges suggest that the nature of IENs transitions is not well understood. IENs are employed in critical care environments, yet transitions into critical care have not been studied. To a large extent, assumptions informing IENs transitions are unproblematized in research, with current research literature mainly focused on the end-point of transitions, for example acculturation, integration, or adaptation. This focus on outcomes, while important, overlooks the organizational processes that produce IENs transitions. Through the lens of organizational theory, this research shifts the focus from outcomes to that of processes in order to see how transitions are accomplished involving a variety of people and materials. Accordingly, this study sought to answer two questions: what knowledges and assumptions related to IENs’ transitions, IENs’ knowledge and learning, and nursing practice are discoverable within organizational strategies for IENs’ transitions, and what knowledges, assumptions, and strategies are discoverable in how ICUs are prepared/made ready for IENs to work there? This study was a focused ethnography occurring over six months within a large, US health system in the Midwestern region. The purpose of the study was to better understand IENs transitions into ICU. Data collection included document review and interviews of ICU staff (including IENs), ICU managers, educators, preceptors, and executives involved in the planning of transitions to this organization. Analysis highlighted the extent to which ‘transitions’ are not so much individual accomplishments but rather the effects of open-ended and fluid relations among various materials and agents, leading to a reconceptualized understanding of transitions as “joining practices.
Geotechnical Characterization of Transitional Oil Sands Tailings
No full textRecent oil sands tailings treatment technologies have led to the formation of deposits with transitional compositions between sand and fines. These intermediate materials remain understudied, resulting in limited understanding of their geotechnical behaviour. This research addresses this gap through a series of laboratory investigations focused on both unsaturated and saturated responses of synthetically prepared samples, created by mixing mature fine tailings (MFT) with sand to achieve sand-to-fines ratios (SFR) between 1 and 3.
The first phase of the study examined shrinkage behaviour and soil water characteristic curves (SWCCs). Results indicated that these materials experienced significant volumetric shrinkage, up to 45% of their original volume upon drying. Air entry values estimated from SWCCs based on gravimetric water content were found to be unrealistic and inconsistently correlated with those defined by saturation as water content designation. Therefore, SWCCs expressed using water saturation were concluded to be more appropriate and accurate for these materials. This finding benefits the industry in determining accurate parameters to model the unsaturated behaviour of these deposits.
The second laboratory study was intended to investigate the consolidation properties of the materials. It was observed that the filterability of these materials decreases with the increase of fines up to the threshold limit of about 35%, beyond which further fines did not significantly affect performance. Clay activity and pore water chemistry were also found to influence hydraulic conductivity. One-dimensional consolidation model revealed that co-deposition at the threshold fines content improved performance by reducing both settlement magnitude and consolidation time by about 50%. These findings inform optimal sand-fines blending strategies at the point of deposition to enhance deposit performance.
The third laboratory study involved the use of the vane shear test (VST) and fall cone test (FCT) to determine their reliability in measuring the undrained strength of these deposits. A strong correlation was observed between the VST and FCT results up to 60 kPa. Both methods also aligned well with strength values inferred from the liquidity index, supporting their applicability in assessing the undrained strength of transitional tailings. This finding brings assurance to the industry to use VST or FCT in measuring undrained strength as required to be reported as one of the performance indicators of deposits.
The final phase investigated strength mobilization through consolidated undrained triaxial testing. Results showed that shear strength and friction angle increased with sand content. It was also noted that shear strength decreased with activity; a phenomenon attributed to an increase in water-holding capacity, which enhances lubricity as activity increases. Samples with up to 28% fines exhibited dilative behaviour, while those with 34% fines and above shifted to contractive response, indicating a threshold point in between. Their brittleness index increased with fines content up to 36 ± 2%, beyond which the trend declined. No clear trend was observed between the Brittleness Index and the MBI, suggesting that clay activity may not significantly influence the Brittleness Index. These findings identify a fines threshold critical for strength behaviour, offering practical guidance for designing co-deposited tailings with targeted strength performance
Optimization of Pit Shells in the Presence of Geological Uncertainty
No full textThe optimization of ultimate pit limits is a critical step of mine planning, where geological uncertainty can significantly impact the profitability of a mining project. Traditional approaches often rely on a single geological model that overlooks geological uncertainty that influences pit design and economic outcomes. In recent years, there has been a shift toward stochastic geological modeling to better account for this uncertainty.
Several methods have been developed to incorporate multiple geological realizations into ultimate pit limit determination. One such method is the Heuristic Pit Optimizer (HPO) approach proposed by Acorn and Deutsch. This research evaluates the performance of the HPO method in comparison to earlier techniques, demonstrating its superiority under a Risk-Neutral (RN) strategy. The HPO method consistently yields higher expected pit values across multiple geological scenarios.
This thesis introduces an enhancement to the original HPO method by incorporating an improved risk metric. Specifically, the modified approach utilizes the Lower Partial Moment (LPM) as a measure of downside risk, enabling the generation of more profitable pit configurations across varying levels of risk. The application of the lower partial moment mitigates risk without unnecessarily sacrificing high-value outcomes. Notably, the proposed method yields pit value distributions characterized by a longer upper tail, indicating a higher probability of achieving more favorable economic outcomes.
A sensitivity analysis is also conducted, examining the effects of risk factor on pit limit, expected pit value, risk measures, and the overall distribution of economic outcomes. The results indicate that while more conservative strategies (i.e., lower risk tolerance) lead to reduced expected values, the proposed method consistently delivers higher expected returns at each risk level compared to the original version. Furthermore, the modified HPO framework supports Opportunity-Seeking (OS) strategies by increasing the likelihood of high-value outcomes, although at the cost of increased risk and reduced expected value.
To validate the practical applicability of the method, a real-world dataset is employed. The findings confirm that the HPO approach outperforms traditional methods under a RN strategy. Moreover, the proposed enhancement yields more profitable pit outcomes across all risk levels when compared to the original HPO formulation.
Additionally, this study explores the definition of pushbacks by reducing economic block values through various functional approaches. The impact of different reduction functions on the final profitability of pushbacks is assessed for a range of pushback sizes. A Hybrid Cost-Price adjustment function is also proposed, which demonstrates improved performance in identifying economically
viable pushbacks, particularly in the early stages of mine development, based on the real-case dataset
Mechanochemical Processing, Sintering Processing, and Substitution Design of Solid-State Electrolytes for Na-ion and Li-ion Batteries
No full textThis thesis presents the synthesis, processing, and analysis of ternary sodium (Na) and lithium (Li) solid-state inorganic electrolytes, with the goal of investigating their electrochemical properties, morphologies, and crystal structures. The study aims to provide insight into their potential applications in all-solid-state battery fabrication and other energy storage devices.
The first part of the thesis focuses on the sodium-based solid-state electrolyte, W-substituted Na3SbS4 (WNSS), selected for its high reported ionic conductivity of 42 mS/cm. The first project (Chapter 3) explores the mechanical milling processing of as-synthesized WNSS to densify the material, improve surface and interior pellet morphology, examine structural changes, and decomposition. It was observed that unsubstituted Na3SbS4 exhibited enhanced morphology and surface contact after milling, whereas WNSS decomposed to form WS₂ impurities. Additionally, a phase transition from the tetragonal P4 ̅2_1 c to the more ionic conductive cubic I4 ̅3m phase was identified from X-ray absorption spectra. The second project (Chapter 4) continues the investigation of WNSS by examining the limits of W substitution and its correlation with ionic conductivity. Powder X-ray diffraction revealed that up to 16% W substitution could be achieved without significant impurities. Raman microscopy detected residual WS₂ impurities post-synthesis and sintering, which was not fully understood in prior studies. Furthermore, plasma focused ion beam-scanning electron microscopy (PFIB-SEM) was used to compare sintered and as-synthesized pellets for their surface morphology and interior void spaces. This provided direct evidence that sintering improved both densification and surface morphology relative to the pristine samples. The second part of the thesis (Chapter 5) shifts focus to the lithium-based ternary halide electrolyte Li3InCl6. Substitution strategies involving Ga, Br, and I were employed to potentially modify the electrochemical properties of the parent structure, testing the limit of Hume-Rothery rules. Notably, the study disproves earlier reports suggesting that a full solid solution of Br-substituted Li3InCl6 is achievable, indicating a more urgent need for complete structural analysis for substituted materials
Systematizing Machine Learning of Multilingual Speech for Cognitive Health Assessment
No full textSpeech is an important cognitive health biomarker, useful for detecting cognitive decline. Prior research provides evidence for this hypothesis, which has motivated a wave of machine learning (ML) methods that use the various representations of acoustic and linguistic features of speech. We therefore anticipate the need to reproduce and replicate prior experiments with larger, more representative, and demographically diverse datasets collected from different populations.
This thesis tackles this challenge by developing three multi-functional and configurable software pipelines for (1) audio preprocessing and acoustic feature extraction, (2) text preprocessing and linguistic feature extraction, and (3) machine learning model training, evaluation, and prediction. Together, these three pipelines cover a breadth of ML methods, enabling the replication of most state-of-the-art related research.
We applied the pipelines for Automated Machine Learning (AutoML). There are two prevailing AutoML procedures for Combined Algorithm Selection and Hyperparameter Optimization (CASH), i.e., nested and flat cross-validation. The choice is quite impactful in terms of computational efficiency, but it is not clear whether the two methods influence ML performance. We have investigated this problem in the context of multilingual cognitive health prediction using the combined benchmark datasets in this area of research for English, Greek, and Chinese speakers. Our experiment covers linear, kernel-based, tree-based, and neural network models. This thesis has three major contributions: (1) a suite of configurable software pipelines called LuigiML that implement a comprehensive set of tasks typically involved in machine learning experiments for predicting cognitive health labels from spoken language, (2) the development of five datasets that, together, can be used to conduct cognitive health assessment experiments across languages, speech tasks, and cognitive health status, (3) an empirical investigation of CASH procedures with benchmark datasets, and (4) AutoML procedure, based on the machine-learning and experiment-configuration pipelines, with performance that is comparable to the state-of-the-art
Experimental evidence that organo-mineral interactions regulate dissolved organic matter bioavailability across permafrost landscapes of the western Canadian Arctic
No full textThe fate of permafrost-origin dissolved organic carbon shapes northern food webs and affects regional and global carbon balances. Substantial variation in Arctic landscapes, and therefore the composition of permafrost sediments, challenges our ability to predict this fate, constraining both knowledge of local-scale effects and upscaling exercises. The western Canadian Arctic is a diverse permafrost landscape shaped by the advance and recession of the Laurentide Ice Sheet, ground ice preservation and development, climate variability, and past thaw and reworking of materials. These factors give rise to significant variation in responses to freshwater dissolved organic carbon (DOC) concentrations and dissolved organic matter (DOM) composition to permafrost thaw. Regional observations of decreased DOC concentrations and increased DOM susceptibility to biodegradation in thaw-impacted fluvial networks suggest that organo-mineral interactions may regulate DOC bioavailability by “protecting” DOM from biodegradation. However, the potential for the formation of organo-mineral interactions in thawed permafrost-affected sediments and their variability across permafrost sediment types is not well understood. Using batch sorption experiments, we assessed sorption potential, water-extractable DOC concentration, and the impact of sorption on DOM composition of six different permafrost sediment types common across the western Canadian Arctic. Sediment biogeochemistry and sorption properties were influenced by geological origin, with increased variation associated with past thaw. Sorption coefficients were positively correlated with organo-reactive forms of Al and Fe and negatively with sediment pH. While all sediment samples showed evidence of DOC sorption, yedoma from the Klondike region had lower sorption coefficients than sediments from regions previously glaciated by the Laurentide Ice Sheet. Exposure to thawed permafrost sediment enabled preferential sorption of larger, humic-like organic compounds and displacement of mineral-bound small, aliphatic molecules, thereby enriching the DOM pool with more bioavailable compounds. Shifts in DOM composition resulted in a corresponding increase in biodegradation. Our experiments demonstrate that organo-mineral interactions are likely to decrease DOC concentration while increasing DOM bioavailability of freshwater ecosystems in response to permafrost thaw, but the strength of this response will vary both across and within landscapes of the permafrost region
Response of terrestrial birds to climate-amplified shrub dominance in boreal mountains of Yukon, Canada
No full textShrubs are expanding upslope and to higher latitudes due to increasing global temperatures, potentially affecting bird species that breed in subalpine, alpine, and tundra habitats. Studies have found variable non-linear relationships between bird abundance and shrub characteristics across latitudinal gradients in Alaska that indicate potential negative effects of shrubification (increases in woody plant growth, distribution, and relative abundance) on both alpine tundra and subalpine birds. Our study examined similar relationships between bird abundance and shrub dominance along elevational gradients at 10 montane sites in southwest Yukon, Canada. We assessed how vegetation (shrub height, density) and topography (elevation, aspect) influenced high elevation bird abundance, compared these relationships to those observed in Alaska, projected shrub expansion impacts at each of our 10 mountain sites, and identified bird species of potential conservation concern. Using autonomous recording units (ARUs) for bird surveys and conducting ground-based vegetation sampling, we modeled relationships between 17 bird species and vegetation and topography using GLMMs, and assessed potential shrub expansion using broad-scale landcover classification and historical examples of shrub expansion on mountains. Our results revealed: (1) the relative abundance of alpine-associated birds was affected primarily by vegetation, while subalpine-associated birds responded to both vegetation (shrub height, shrub stem count) and topography (elevation, aspect); (2) many species exhibited complex non-linear responses including positive and negative exponential relationships and threshold relationships, with several species showing peak relative abundance at moderate shrub heights or elevations; (3) projected shrub expansion would affect mountains inconsistently, potentially eliminating 90-100% of alpine bird habitat on four mountains under average expansion scenarios; and (4) both alpine- and subalpine-associated species may be at risk from climate amplified shrub expansion due to their negative or threshold responses to shrub dominance combined with restricted elevational ranges in the Yukon. These findings highlight the complexity and variability of mountain subalpine zones, the importance of broad-scale topography in driving bird species abundance, and the interplay between vegetation, topography, and bird distribution in sensitive northern mountain ecosystems
Down-Regulation and Mutation of Pectin Biosynthesis and Flowering Time Genes as a Possible Means of Enhancing Biomass Yield and Digestibility in Alfalfa (Medicago sativa)
No full textAlfalfa (Medicago sativa) is the most widely cultivated perennial forage legume in the world. Its great economic importance in the beef and dairy industries is owed to its many favourable traits, including relatively high quality and yield, and symbiotic nitrogen-fixing capabilities. However, the projected increase in global demand for beef and dairy products and the loss of arable land to urbanization necessitate further improvement to productivity. Moreover, the inefficient conversion of plant biomass into animal products during rumen fermentation results in both economic losses and negative environmental impacts. Thus, digestibility provides another important trait for enhancement in this species. Several strategies have been proposed for the simultaneous improvement of biomass yield and/or digestibility. One such strategy is the down-regulation or mutation of flowering time genes, such as SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), which has been previously demonstrated to delay flowering, resulting in improvements to vegetative biomass production and digestibility in several plant species. Another is the down-regulation or mutation of the pectin biosynthesis gene GALACTURONOSYLTRANSFERASE 4 (GAUT4), which has been previously demonstrated to improve both dry matter yields and extractability of cell wall sugars in plant species grown for bioethanol production. As such, the overall aim of this study was to determine the effects of down-regulating or mutating these genes in alfalfa. RNA interference (RNAi) vectors were designed, generated, and transformed into alfalfa via Agrobacterium-mediated transformation in order to individually down-regulate the expression of MsSOC1a and MsGAUT4a. These RNAi genotypes were then evaluated for changes to morphological characteristics, as well as carbohydrate composition and drought tolerance in the case of MsGAUT4a, as a means of evaluating the potential of these genes as candidates for future improvement of alfalfa. CRISPR/Cas9 mutants of MsSOC1a and MsGAUT4a were also generated as a source of germplasm for future study and development. The RNAi-mediated down-regulation of MsSOC1a resulted in delayed flowering, reduced biomass, and altered stem architecture, while the down-regulation of MsGAUT4a resulted in reduced galacturonic acid, increased nitrogen content and in vitro ruminal gas production, and increased sensitivity to drought stress. Future evaluation of the CRISPR/Cas9-mediated MsSOC1 and MsGAUT4a mutants generated in this study is warranted for further elucidation of the precise functions of these genes in alfalfa, as well as their viability as target genes for further improvement of agronomic traits in alfalfa. If successful, these genes could serve as targets for future molecular breeding of alfalfa to improve both our ability to meet the rising demand for ruminant products, as well as the environmental sustainability of livestock production
Photoaging of Polyvinyl Chloride and Polystyrene Under UVA Radiation in Diverse Environmental Conditions
No full textPlastic pollution has become a major environmental issue due to extensive use, durability, and poor waste management practices. Once plastics are released into the environment, they undergo aging processes that include mechanical abrasion, temperature changes, and exposure to oxygen and UV radiation, causing them to break down into microplastics. These microparticles can accumulate in the environment and present unknown health risks to humans and animals. Plastics aging studies have been conducted using techniques including thermal, chemical and photodegradation (frequently with UVB or UVC radiation). Physical changes have been identified, such as brittleness, discoloration, surface roughness, and cracks. Additionally, chemical oxidation and the formation of new functional groups such as carbonyl and hydroxyl moieties have been reported. However, UVA radiation is not as well studied, even though it is the primary type of UV radiation reaching the Earth’s surface. This study investigates the photoaging of polyvinyl chloride (PVC) and polystyrene (PS) under UVA radiation (365 nm), after 108 days of exposure using a custom-built setup delivering high irradiance conditions at 78 W/ m2, corresponding to the equivalent of over two years of natural sunlight at mid-latitudes and around 5 years in polar conditions. Four different simulated environments were studied: air, seawater (SW, 0.56 M NaCl), freshwater (FW, 0.01 M NaCl), and ultrapure water (UW). Physical changes were monitored through scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), while chemical changes were evaluated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Changes in surface reactivity were assessed through potentiometric titrations and modeling to quantify newly formed acidic groups and their pKa values.
Results indicate that PVC exhibited significant photostability in air, FW, and UW, with no detectable physical or chemical changes. However, SW-aged PVC showed a temporary increase in the vinyl index (1620 cm⁻¹) and slight alterations in surface protonation behavior at high pH. However, this did not support the formation of distinct proton-active sites. In contrast, PS underwent noticeable photo-oxidation across all conditions, evidenced by yellowing, and spectroscopic analyses that showed meaningful changes, especially increases in the carbonyl (1718 cm-1) and the hydroxyl (3458 cm-1) indices and decreases in aliphatic C–H (2919 cm⁻¹) and aromatic ring deformation (752 cm-1) band intensities. Potentiometric titration data fit well by invoking three acidic surface sites with pKa values of ≈ 5.49, 7.76, and 9.98, corresponding to carboxylic acid groups, phenolic groups, and hydroperoxides, respectively. No morphological changes were observed in SEM-EDS.
These findings demonstrate the influence of polymer composition and ionic medium in UVA photoaging. While PS becomes chemically reactive and may act as a pollutant carrier, PVC persists with minimal surface modification, representing primarily a physical hazard in aquatic environments
Suzanne Watts - Abstract 39 - Innovate Conference 2025
No full textThis workshop presents an innovative approach to simulation training by harnessing the power of gamification. As the educational landscape evolves, gamification offers a dynamic strategy to enhance staff readiness for high-stakes scenarios. Built upon the success of an Amazing Race-inspired in-service ("A-MHP-zing Race"), this approach prepared staff for a multidisciplinary simulation involving a Massive Hemorrhage Protocol