The Accuracy of Wrist-worn Heart Rate Monitors across a Range of Exercise Intensities

Commercially available wrist-worn heart rate (HR) monitors have become increasingly popular. However, the accuracy of the devices across a range of exercise intensities is largely unknown. This study investigated the accuracy of four wrist-worn HR monitors (Apple Watch Series 1, Fitbit Charge, TomTom Touch, and Mio Fuse). Eighteen adults completed three trials on a cycle ergometer wearing a chest-worn HR monitor (Polar). Trial 1 established the HR-power output relationship, and resting and maximum HR. In trials 2 and 3, participants were fitted to an electrocardiogram (ECG) and completed a step test consisting of 5 x 3 minute stages at 40 - 80% of HR reserve (determined in trial 1) whilst wearing two wrist-worn HR monitors. Relative to ECG, there were no differences in HR between the devices during exercise (p = 0.239), and no device × exercise intensity interaction (p = 0.370). There were no instances where ECG and Polar data differed by ≥ 5 b·min-1. Conversely, there were two instances (2.2%) with the Apple, four (4.4%) with the Mio, 10 (11.1%) with the TomTom, and 19 (21.1%) with the Fitbit. A chest-worn HR monitor offers greater accuracy compared to wrist-worn devices

A deep residual architecture for skin lesion segmentation

In this paper, we propose an automatic approach to skin lesion region segmentation based on a deep learning architecture with multi-scale residual connections. The architecture of the proposed model is based on UNet [22] with residual connections to maximise the learning capability and performance of the network. The information lost in the encoder stages due to the max-pooling layer at each level is preserved through the multi-scale residual connections. To corroborate the efficacy of the proposed model, extensive experiments are conducted on the ISIC 2017 challenge dataset without using any external dermatologic image set. An extensive comparative analysis is presented with contemporary methodologies to highlight the promising performance of the proposed methodology

Functional Stability of Transfemoral Amputee Gait Using the 3R80 and Total Knee 2000 Prosthetic Knee Units

Prosthetic knee designs have become extremely sophisticated compared to early constant friction single axis mechanisms. Today, prosthetists and physicians have a wide variety of components to choose from for their transfemoral amputee patients. Unfortunately, there are little quantitative data comparing the performance of different types of prosthetic components, and prosthetic prescription is often based on empirical knowledge and experience, rather than objective comparison of prosthetic designs. This study used gait analysis to objectively evaluate the stability characteristics of two types of prosthetic knee designs, the polycentric Total Knee 2000 (Ossur, Aliso Viejo, CA) and the single axis 3R80 stance control knee (Otto Bock Healthcare, Minneapolis, MN). Five healthy, active transfemoral amputees participated in this study by completing two gait analysis sessions, one with the Total Knee 2000 and one with the 3R80. At the end of each session, subjects were asked to complete a questionnaire for comparison of their subjective preferences with the objective biomechanical measures from the gait analysis. Kinematic and kinetic gait data were collected. Stride and temporal parameters (i.e., velocity, cadence, stride length, step length, stance and swing phase durations, and single and double support durations), joint angles and moments were computed from the Vicon data. A within subjects statistical analysis was then conducted, using repeated measures ANOVA, to determine if there were significant differences in performance between the two knee designs. The stride and temporal parameters computed in this study indicated that the Total Knee 2000 demonstrated a high degree of overall stability compared to the 3R80. The differences in inherent mechanical stability in the Total Knee 2000 and the 3R80 resulted in different calculated hip moments. The corresponding required hip moments indicated that the relative stability of the two knee designs changed throughout the gait cycle due to the polycentric nature of the Total Knee 2000. Specifically, the Total Knee 2000 was found to be less stable than the 3R80 in early stance and more stable than the 3R80 in mid- and late-stance. In addition to the biomechanical evidence of increased stability with the Total Knee 2000, the responses to the subjective questionnaires indicated that most subjects felt more stable and more confident bearing weight on the Total Knee 2000 than the 3R80

Challenges and resilience: managers' perceptions of firm performance following M&As

We study M&As, resilience and performance, identifying links between managers’ perceptions of performance and resilience, using trans-national organisational-level survey evidence (N=3613) and follow up semi-structured in-depth interviews with managers involved in M&As and demerger. Drawing on the resilience and M&A literature, we identify reasons why employees in acquired firms may be less resilient in coping with the resultant changes than those of the acquirer and why this will negatively impact perceptions of performance. We explore the causes and consequences of variations in resilience and performance within firms that acquire others, and in those that have been demerged. As anticipated, we find that although managers in acquired firms tended to report worse performance than those in acquiring firms, both tended to be more positive than firms that had not taken part in an M&A at all. We draw out implications for theory and practice

Silent Transitions in Automata with Storage

We consider the computational power of silent transitions in one-way automata with storage. Specifically, we ask which storage mechanisms admit a transformation of a given automaton into one that accepts the same language and reads at least one input symbol in each step. We study this question using the model of valence automata. Here, a finite automaton is equipped with a storage mechanism that is given by a monoid. This work presents generalizations of known results on silent transitions. For two classes of monoids, it provides characterizations of those monoids that allow the removal of \lambda-transitions. Both classes are defined by graph products of copies of the bicyclic monoid and the group of integers. The first class contains pushdown storages as well as the blind counters while the second class contains the blind and the partially blind counters.Comment: 32 pages, submitte

F/A-18 1/9th scale model tail buffet measurements

Wind tunnel tests were carried out on a 1/9th scale model of the F/A-18 at high angles of attack to investigate the characteristics of tail buffet due to bursting of the wing leading edge extension (LEX) vortices. The tests were carried out at the Aeronautical Research Laboratory low-speed wind tunnel facility and form part of a collaborative activity with NASA Ames Research Center, organized by The Technical Cooperative Program (TTCP). Information from the program will be used in the planning of similar collaborative tests, to be carried out at NASA Ames, on a full-scale aircraft. The program covered the measurement of unsteady pressures and fin vibration for cases with and without the wing LEX fences fitted. Fourier transform methods were used to analyze the unsteady data, and information on the spatial and temporal content of the vortex burst pressure field was obtained. Flow visualization of the vortex behavior was carried out using smoke and a laser light sheet technique

Informal collaborative learning (ICL) – student perspectives on the role of informal collaborative learning ICL in higher education

The Covid 19 pandemic requires critical re-evaluation of the way Higher Education can help students maximise their learning to adjust and adapt to a new reality. This requires a holistic approach which extends beyond consideration of student learning in formal settings to understanding the role informal learning can play. Whilst research exists on informal independent learning, less focus has been placed on how students collaborate informally as part of their learning process. In this study interviews with HE students in Spain and the UK offer insight into variable but beneficial informal collaborative learning (ICL) practices. The value attributed to ICL emphasises its potential contribution to the current educational landscape and the merit of recognising it as a distinct concept. Further, uneven access and the role of learner maturity signal the potential for universities to enhance learning and increase access by playing an active a role in developing ICL skills and personal networks

Transport strategy in Scotland since devolution

This article critically reviews how the Scottish Executive's approach to transport has developed since devolution. Although there is much to commend, a number of concerns can be identified, including the possibility that a number of strategic infrastructure schemes appear to have been approved on political rather than on technical grounds. It is difficult to know whether the current set of transport infrastructure investment plans represents good value for public money

Interpreting physical performance in professional soccer match-play: Should we be more pragmatic in our approach?

Academic and practitioner interest in the physical performance of male professional soccer players in the competition setting determined via time-motion analyses has grown substantially over the last four decades leading to a substantial body of published research and aiding development of a more systematic evidence-based framework for physical conditioning. Findings have forcibly shaped contemporary opinions in the sport with researchers and practitioners frequently emphasising the important role that physical performance plays in match outcomes. Time-motion analyses have also influenced practice as player conditioning programmes can be tailored according to the different physical demands identified across individual playing positions. Yet despite a more systematic approach to physical conditioning, data indicate that even at the very highest standards of competition, the contemporary player is still susceptible to transient and end-game fatigue. Over the course of this article, the author suggests that a more pragmatic approach to interpreting the current body of time-motion analysis data and its application in the practical setting is nevertheless required. Examples of this are addressed using findings in the literature to examine: a) the association between competitive physical performance and ‘success’ in professional soccer, b) current approaches to interpreting differences in time-motion analysis data across playing positions and, c) whether data can realistically be used to demonstrate the occurrence of fatigue in match-play. Gaps in the current literature and directions for future research are also identified

Situations and mechanisms of non-contact knee injury in adult netball: A systematic review

Objectives Noncontact knee injuries in netball are a concern due to a range of negative consequences. To reduce the number of injuries, identifying the situation and mechanism of injury is important. This systematic review examined the literature reporting the situation and mechanism of noncontact knee injury in netball. Design Systematic Review. Methods PRISMA guidelines were followed and specific key-term combinations used to search databases. Descriptive and analytic-observational studies reporting the situation or mechanism of noncontact knee injury in females playing netball were included (evaluated using frequency counts). Results Six articles were included (combined sample 11,401). Players self-reported the situation of injury in five studies, only one study reported both the situation and mechanism of injury. Landing was the most reported situation of knee injury, representing 46.6% of all knee injuries whilst knee abduction (valgus) collapse was the most observed mechanism. Situation and mechanism of noncontact knee injury in netball were not adequately reported. Conclusions Despite the variations in reporting methods, landing is the most common situation of injury. As only one study reported mechanism of injury, it is difficult to draw conclusions but the mechanism of noncontact knee injury in netball appears similar to those identified in other female athletes