The Determination of Dendrite Coherency Point Characteristics Using Three New Methods for Aluminum Alloys

The aim of this work is to give an overview of existing methods and to introduce three new methods for the determination of the Dendrite Coherency Point (DCP) for AlSi10Mg alloys, as well as to compare the acquired values of DCP based on a thermal analysis and on the analysis of cooling curves working with only one thermocouple. Additionally, the impact of alloying and contaminant elements on the DCP will be also studied. The first two proposed methods employ the higher order derivatives of the cooling curves. The DCP was determined as the crossing point of the second and third derivative curves plotted versus time (method 1) or that of the temperature (method 2) with the zero line just after the maximum liquidus temperature. The third proposed method is based on the determination of the crossing point of the third solid fraction derivative curve with the zero line, corresponding to a minimum of the second derivative. A Taguchi design for the experiments was developed to study the DCP values in the AlSi10Mg alloy. The DCP temperature values of the test alloys were compared with the DCP temperatures predicted by the previous methods and the influence of the major and minor alloying elements and contaminants over the DCP. The new processes obtained a correlation factor r2 from 0.954 and 0.979 and a standard deviation from 1.84 to 2.6 °C. The obtained correlation values are higher or similar than those obtained using previous methods with an easier way to define the DCP, allowing for a better automation of the accuracy of DCP determination. The use of derivative curves plotted versus temperature employed in the last two proposed methods, where the test samples did not have an influence over the registration curves, is proposed to have a better accuracy than those of the previously described methods.This work has been partially funded by the Basque Government through the ETORGAI programme ZE-2016/00018 and from the European Union’s Seventh Programme for research, technological development and demonstration under grant agreement No. 296024

A Profile of Canadians Over the Age of 65 Years Living with Coexisting Vision and Mobility Impairments: A Sequential Mixed Method Analysis

The purpose of this dissertation was (i) to investigate the prevalence of older Canadian adults living with coexisting vision and mobility impairments, and (ii) to describe how disability associated with both impairments relate to health status, activities of daily living, physical activity participation, assistive technology use, and health care services. These goals were achieved by using mixed methodology approach. The first manuscript was based on secondary analyses of the 2006/2007 National Population Health Survey (NPHS). The results of the secondary analysis of the NPHS revealed that approximately 3% of the Canadian population over the age of 65 was living with coexisting vision and mobility impairments. Also, older adults with both conditions required more assistance with activities of daily living and they reported the lowest levels of physical activity participation compared to those living with one or no impairment. The second part of the core component was based on secondary analyses of the 2006 Participation and Activity Limitations Survey (PALS). The PALS was specifically designed for individuals who reported they were living with a disability. As a result, a greater proportion of respondents indicated the presence of both target conditions – approximately 15% of older Canadians who reported having a disability were living with coexisting vision and mobility impairments. The analysis of the PALS data revealed that older adults with both impairments required more assistance with activities of daily living and they reported a higher use of assistive technology; however, there was a higher level of unmet needs for vision related assistive technology. The final manuscript consisted of in-depth interviews conducted to add the personal perspective of older adults with both impairments, and to expand and clarify the quantitative findings. The analyses of the transcripts revealed four main themes among participants: (i) the meaning behind vision, mobility, and coexisting impairments; (ii) adaptation of desired activities; (iii) external support for engaging in activity; and (iv) internal support for engaging in activity. The results of this dissertation contribute knowledge about living with coexisting vision and mobility impairments and offer a starting point to guide rehabilitation services for clients with multiple impairments

Transfer Learning to Detect COVID-19 Coughs with Incremental Addition of Patient Coughs to Healthy People's Cough Detection Models

Millions of people have died worldwide from COVID-19. In addition to its high death toll, COVID-19 has led to unbearable suffering for individuals and a huge global burden to the healthcare sector. Therefore, researchers have been trying to develop tools to detect symptoms of this human-transmissible disease remotely to control its rapid spread. Coughing is one of the common symptoms that researchers have been trying to detect objectively from smartphone microphone-sensing. While most of the approaches to detect and track cough symptoms rely on machine learning models developed from a large amount of patient data, this is not possible at the early stage of an outbreak. In this work, we present an incremental transfer learning approach that leverages the relationship between healthy peoples' coughs and COVID-19 patients' coughs to detect COVID-19 coughs with reasonable accuracy using a pre-trained healthy cough detection model and a relatively small set of patient coughs, reducing the need for large patient dataset to train the model. This type of model can be a game changer in detecting the onset of a novel respiratory virus.Comment: This paper has been accepted to publish at EAI International Conference on Wireless Mobile Communication and Healthcare (MobiHealth'23

Longitudinal impact of newly acquired closed-circuit televisions (CCTV) on quality of life for low vision patients

Ongoing efforts to quantify changes in quality of life attributable to low vision rehabilitation have focused on the utility of a single test instrument to measure this multidimensional concept. It is hypothesized that quality of life is best assessed using multiple instruments to capture some of its component facets, including functional status and psychosocial impact. Low vision devices have a predictably spontaneous impact on functional vision status, but associated psychosocial impact occurs with different magnitudes and over more protracted time intervals. The National Eye Institute Visual Function Questionnaire (NEI VFQ-25) measures the functional status of individuals in key vision areas that are associated with quality of life. The Psychosocial Impact of Assistive Devices Scale (PIADS) is an instrument that measures the psychosocial impact of assistive device intervention in three quality of life domains: competence, adaptability, and self-esteem. 68 participants were obtained from an ongoing parent study. These participants were recruited through the Low Vision Clinic at the University of Waterloo. They had a primary diagnosis of age-related macular degeneration (ARMD) and were obtaining a CCTV system for the first time. Assessments from the parent study used in this thesis included follow-up from 2 weeks, 1 month, 3 months, and 6 months post-adoption of the CCTV. The two tests administered were to measure functional vision status (NEI VFQ-25) and perceived psychosocial impact (PIADS), according the framework outlined by the Consortium for Assistive Technology Outcomes Research (CATOR). Multivariate repeated-measures ANVOA results confirmed that CCTV systems have an immediate and robust effect on the daily visual functioning of their users, and that this effect is stable over long periods of device use. The psychosocial impact of CCTV device use peaks in the shorter term and then seems to wane in the longer term for reasons that are not yet understood. The NEI VFQ-25 and the PIADS appear to have differential sensitivity to important influences on low vision rehabilitation outcomes. This project has demonstrated the value of longitudinal outcomes research in low vision rehabilitation. After obtaining a CCTV, visual function status remains static while psychosocial impact is dynamic during 6-months of follow-up

Profiles of fire suppression contracting businesses

2 pagesFederal agencies are increasingly relying on contracts to respond to wildfire. Although present since the 1970s, private equipment contractors have come to play an important role following extreme fire seasons in the 1990s. Understanding how these businesses operate and provide equipment for suppression work is critical for ensuring that sufficient and efficient resources are available for wildfire suppression when it is needed. In this research, we investigated the types of businesses that contract equipment for federal fire suppression in the Pacific Northwest, and the strategies they use to both meet unpredictable demand and remain profitable.This research was supported by funding from the Joint Fire Science Program

The Correlation between Confidence and Knowledge of Evidence-Based Practice among Occupational Therapy Students

Evidence-based practice (EBP) is used throughout multiple health-care professions and includes the use of best research available, client preferences, and the practitioner’s experience. Occupational therapy educational programs are required to incorporate EBP into their curriculum. A convenience sample of occupational therapy students from a private university completed a survey designed to measure students’ knowledge and confidence in EBP. The survey consisted of the Knowledge of Research Evidence Competencies (K-REC) and the Evidence-Based Practice Confidence (EPIC) scale, as well as demographic questions. Of the respondents (n = 47), third-year students indicated higher confidence in the ability to utilize EBP and higher levels of knowledge related to EBP than second- or first-year students. The more didactic and clinical experience that the students had, the more knowledge related to EBP they had, which increased their confidence in the implementation of EBP. The knowledge and confidence that students gain of EBP within their educational training and clinical experiences can influence their future use and implementation of EBP as clinicians. Without this information, therapists will lack the confidence and ability to apply EBP principles in a changing and demanding health-care environment

Nd Isotopic Structure of the Pacific Ocean 70-30 and Numerical Evidence for Vigorous Ocean Circulation and Ocean Heat Transport in a Greenhouse World

The oceanic meridional overturning circulation (MOC) is a crucial component of the climate system, impacting heat and nutrient transport, and global carbon cycling. Past greenhouse climate intervals present a paradox because their weak equator-to-pole temperature gradients imply a weaker MOC, yet increased poleward oceanic heat transport appears to be required to maintain these weak gradients. To investigate the mode of MOC that operated during the early Cenozoic, we compare new Nd isotope data with Nd tracer-enabled numerical ocean circulation and coupled climate model simulations. Assimilation of new Nd isotope data from South Pacific Deep Sea Drilling Project and Ocean Drilling Program Sites 323, 463, 596, 865, and 869 with previously published data confirm the hypothesized MOC characterized by vigorous sinking in the South and North Pacific ~70 to 30 Ma. Compilation of all Pacific Nd isotope data indicates vigorous, distinct, and separate overturning circulations in each basin until ~40 Ma. Simulations consistently reproduce South Pacific and North Pacific deep convection over a broad range of conditions, but cases using strong deep ocean vertical mixing produced the best data-model match. Strong mixing, potentially resulting from enhanced abyssal tidal dissipation, greater interaction of wind-driven internal wave activity with submarine plateaus, or higher than modern values of the geothermal heat flux enable models to achieve enhanced MOC circulation rates with resulting Nd isotope distributions consistent with the proxy data. The consequent poleward heat transport may resolve the paradox of warmer worlds with reduced temperature gradients

Leukocyte coping capacity as a complementary stress metric in migrating birds

Corticosterone (Cort) is involved in multiple physiological processes during bird migration, complicating its interpretation in a stress context. We investigated whether the leukocyte coping capacity (LCC) provides useful complementary information on the stress response in migratory Garden Warblers (Sylvia borin) and how it relates to Cort and energetic condition. Contrary to Cort levels, LCC significantly decreased, implying high-stress levels and a diminished capacity to recover after a stressful event. The absence of significant effects of body conditions on the stress parameters shows no simple relationship between these traits and highlights the need for additional stress metrics to measure stress in life-history contexts