Search

Additive Manufacturing (AM) is receiving widespread attention from both industry and academia who are looking to benefit from the numerous advantageous possibilities that AM processes have to offer, such as the potential to design and produce highly complex bespoke geometries with minimal material wastage. Yet, despite this, AM also has some drawbacks. Some of the most significant include the presence of process-induced defects and the inherent surface roughness of an AM built component, both of which can have a considerable influence on the mechanical properties of the final product. This research will investigate the role of an as-built surface on the fatigue properties of AM Ti–6Al–4V manufactured by electron beam melting (EBM), laser powder bed fusion (L-PBF) and laser metal deposition with wire (LMD-w). Fatigue results have been generated alongside advanced surface profilometry, microstructural, defect and fractographic analyses that have revealed that whilst the surface roughness in the majority of instances is the primary factor impacting the fatigue performance on AM material, it cannot be considered alone. It was found that the inherent as-built (AB) surface finish was significantly different across the various AM processes, inducing a range of effective stress concentrations and thus, a contrasting impact on the resulting fatigue performance. Results from each variant have been compared against a machined and polished equivalent, to provide a further consideration as to whether the as-built surface would be suffice from a time and economical viewpoint. Statistical analysis of the generated results also allowed for an extrapolation of predicted fatigue lives in the very high cycle regime for the alternative AM Ti–6Al–4V variants.

Reliable, long-term records of glacier mass change are invaluable to the glaciological and climate-change communities and used to assess the importance of glacier wastage on streamflow. Here we evaluate the in-situ observations of glacier mass change for Place (1982–2020) and Peyto glaciers (1983–2020) in western Canada. We use geodetic mass balance to calibrate a physically-based mass-balance model coupled with an ice dynamics routine. We find large discrepancies between the glaciological and geodetic records for the periods 1987–1993 (Place) and 2001–2006 (Peyto). Over the period of observations, the exclusion of ice dynamics in the model increased simulated cumulative mass change by ~10.6 (24%) and 7.1 (21%) m w.e. for Place and Peyto glacier, respectively. Cumulative mass loss using geodetic, modelled and glaciological approaches are respectively − 30.5 ± 4.5, − 32.0 ± 3.6, − 29.7 ± 3.6 m w.e. for Peyto Glacier (1982–2017) and − 45.9 ± 5.2, − 43.1 ± 3.1, − 38.4 ± 5.1 m w.e. for Place Glacier (1981–2019). Based on discrepancies noted in the mass-balance records for certain decades (e.g. 1990s), we caution the community if these data are to be used for hydrological model development.

This paper reports on the experiences of creative practice graduate researchers and academic staff as they seek to comply with the requirements of the Australian "National Statement on the Ethical Conduct of Research Involving Humans." The research was conducted over a two-year period (2015 to 2017) as part of a wider project 'iDARE -- Developing New Approaches to Ethics and Research Integrity Training through Challenges Presented by Creative Practice Research'. The research identified the appreciation of ethics that the participants acquired through their experience of institutional research ethics procedures at their university. It also revealed a disjunction between the concepts of ethics acquired through meeting institutional research ethics requirements, the notion of ethics that many researchers adopt in their own professional creative practice and the contents of professional codes of conduct. A key finding of the research was that to prepare creative practice graduates for ethical decision-making in their professional lives, research ethics training in universities should be broadened to encompass a variety of contexts and enable researchers to develop skills in ethical know-how.

This study explores how existing connections to natural places may affect PA visitors’ experiences and perceptions within the PA. Specifically, outside-the-PA soundscape perceptions are examined to better understand how their experiences outside the PA may affect perceptions of PA soundscapes and visitors’ ability to effectively contribute to conservation monitoring. Survey research (n=389) of recent urban visitors to the Chilean Coyhaique National Reserve (CNR) in Patagonia unpacked perceptions of the acoustic environments within the places where participants felt most connected to nature, including landscape features, favorite and prevalent sounds, and acceptability of particular anthrophonic sounds. Favorite and prevalent sounds were open-coded, and anthrophonic sounds were rated for prevalence and acceptability. The mountain landscape features and sounds (‘wind’, ‘running water’,‘ birds’) participants described as prominent within the places where they felt most connected to nature aligned well with CNR characteristics. Participants who ‘sometimes’‘/often’ heard certain anthropogenic sounds (vehicles, aircraft, machines, city sounds), within the places where they felt most connected to nature, rated those sounds as more acceptable than participants who reported ‘never’ hearing them, raising concerns about complacency toward anthrophony in natural settings. Continued research efforts are warranted to better understand visitors’ frames of reference, their influence on the reliability of social norm data for PA soundscape monitoring, and their influence on PA managers’ ability to protect conservation values.

Extinction risks for many insect species, particularly across very broad spatial extents, have been linked to the growing frequency and severity of temperatures that exceed the boundaries of their realized niches. Measurement and mitigation of such impacts is hindered by the availability of high-resolution measurements of species-specific severity of extreme weather, especially temperature. While techniques enabling interpolation of broad-scale remote sensing metrics are vital for such efforts, direct remote sensing measurements of thermal conditions could improve habitat management by providing detailed insights that interpolative approaches cannot. Advances in unmanned aerial vehicle (UAV) technology have created opportunities to better evaluate the role of microclimates in local species extinctions. Here, we develop a method to create high-resolution maps of microclimates using UAV and thermal imaging technology that use species’ realized niche boundaries to assess potential effects of severity of extreme temperatures. We generated air temperature maps (5 cm resolution) and canopy height maps (1 cm resolution) for 15 sites in a rare alvar ecosystem in eastern Ontario. We validated these remote sensing observations against independent, in situ temperature observations using iButtons. Temperature observations were accurate and related to physical heterogeneity in alvar habitats. We converted temperature measures into estimates of proximity of thermal niche boundaries for three butterfly species found during field surveys. This is the first time that this method has been applied to high resolution remote sensing observations and offers potential to assess the availability and adequacy of microclimates within habitats at resolutions relevant for conservation management.

Abstract Advances in technological capabilities, operational simplicity and cost efficiency have promoted the rapid integration of unmanned aerial vehicles (UAVs) into ecological research, providing access to study taxa that are otherwise difficult to survey, such as bats. Many bat species are currently at risk, but accurately surveying populations is challenging for species that do not roost in large aggregations. Acoustic recorders attached to UAVs provide an opportunity to survey bats in challenging habitats. However, UAVs may alter bat behaviour, leading to avoidance of the UAV, reduced detection rates and inaccurate surveys. We evaluated the number of bat passes detected with and without the presence of a small, commercial UAV in open habitats. Only 22% of bat passes were recorded in the presence of the UAV (0.23 ± 0.09 passes/min) compared to control periods without the UAV (1.03 ± 0.17 passes/min), but the effect was smaller on the big brown bat/silver-haired bat (Eptesicus fuscus/Lasionycteris noctivagans) acoustic complex. Noise interference from the UAV also reduced on-board bat detection rates. We conclude that acoustic records attached to UAVs may inaccurately survey bat populations due to low and variable detection rates by such recorders.

Potassium channels (Kv) are responsible for repolarizing the action potential in cardiomyocytes. There is a variety of Kv isoforms and corresponding currents (e.g. IKto, IKslow1, IKslow2) that contribute to different phases of repolarization. Because only the sum of their activities can be measured in the form of currents (IKsum), there is a need to delineate individual K+ currents. Most existing studies make inference of Kv activities via curve-fitting procedures but encounter certain limitations as follows: (1) curve-fitting decomposition only relies on the shape of K+ current traces, which does not discern the underlying kinetics; (2) IKsum traces can only be fitted for one clamp voltage at each time, and then analyzed in a population-averaged way later. This paper presents a novel concurrent data assimilation method to calibrate biophysics-based models and delineate kinetics of Kv isoforms with multiple voltage-clamp responses simultaneously. The proposed method is evaluated and validated with whole-cell IKsum recordings from wild-type and chronically glycosylation-deficient cardiomyocytes. Experimental results show that the proposed method effectively handles multiple-response data and describes glycosylation-conferred perturbations to Kv isoforms. Further, we develop a graphical-user-interface (GUI) application that provides an enabling tool to biomedical scientists for data-driven modeling and analysis of Kv kinetics in various heart diseases. [ABSTRACT FROM AUTHOR]

Dilated cardiomyopathy (DCM) is the third most common cause of heart failure and the primary reason for heart transplantation; upward of 70% of DCM cases are considered idiopathic. Our in-vitro experiments showed that reduced hybrid/complex N-glycosylation in mouse cardiomyocytes is linked with DCM. Further, we observed direct effects of reduced N-glycosylation on Kv gating. However, it is difficult to rigorously determine the effects of glycosylation on Kv activity, because there are multiple Kv isoforms in cardiomyocytes contributing to the cardiac excitation. Due to complex functions of Kv isoforms, only the sum of K+ currents (IKsum) can be recorded experimentally and decomposed later using exponential fitting to estimate component currents, such as IKto, IKslow, and IKss. However, such estimation cannot adequately describe glycosylation effects and Kv mechanisms. Here, we propose a framework of simulation modeling of Kv kinetics in mouse ventricular myocytes and model calibration using the in-vitro data under normal and reduced glycosylation conditions through ablation of the Mgat1 gene (i.e., Mgat1KO). Calibrated models facilitate the prediction of Kv characteristics at different voltages that are not directly observed in the in-vitro experiments. A model calibration procedure is developed based on the genetic algorithm. Experimental results show that, in the Mgat1KO group, both IKto and IKslow densities are shown to be significantly reduced and the rate of IKslow inactivation is much slower. The proposed approach has strong potential to couple simulation models with experimental data for gaining a better understanding of glycosylation effects on Kv kinetics.

This paper reports on the experiences of creative practice graduate researchers and academic staff as they seek to comply with the requirements of the Australian National Statement on the Ethical Conduct of Research Involving Humans . The research was conducted over a two-year period (2015 to 2017) as part of a wider project ‘iDARE – Developing New Approaches to Ethics and Research Integrity Training through Challenges Presented by Creative Practice Research’. The research identified the appreciation of ethics that the participants acquired through their experience of institutional research ethics procedures at their university. It also revealed a disjunction between the concepts of ethics acquired through meeting institutional research ethics requirements, the notion of ethics that many researchers adopt in their own professional creative practice and the contents of professional codes of conduct. A key finding of the research was that to prepare creative practice graduates for ethical decision-making in their professional lives, research ethics training in universities should be broadened to encompass a variety of contexts and enable researchers to develop skills in ethical know-how.

This study explores the relationships between, and perceptions of, various exercise motivations and exercise adherence. The application of self-determination theory to exercise motivations research has demonstrated the importance of intrinsic motivations, however, the influence of extrinsic motivations has not been thoroughly examined. This study placed exercise motive perceptions along the Organismic Integration Theory’s (OIT) spectrum of motivations, and identified associations between those interpretations and exercise adherence. Participants (812 college students) completed an online survey detailing their exercise motivations and participation. The Exercise Motivations Inventory-2 (EMI-2) was used to measure exercise motivations, and participants provided open-ended explanations for their ratings of each motivational sub-construct. Total exercise scores were calculated by assigning MET values to exercise bouts using the Leisure Time Exercise Questionnaire. Multiple regression analyses revealed stress management, enjoyment, competition, and weight management as predictors of exercise, and appearance as a negative predictor for females. Analysis of the open-ended motive explanations found participants held diverse perspectives on the health, appearance, weight management, and fitness motivations. The varying interpretations of health and appearance motives ranged across the OIT. Based on motivation theory, they may be conducive to the process of internalization, meaning they may develop into more intrinsic motivations as participants achieve goals and develop a sense of value for the exercise activities. Additional patterns were identified that require further research, including a gap between genders with respect to exercise enjoyment, and the difference between weight management and appearance as predictors of exercise adherence.