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

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

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

Do institutional arrangements make a difference to transport policy and implementation? Lessons for Britain

This paper describes local government decision-making in transport in three areas of the UK, London, West Yorkshire and Edinburgh, in which major changes in local government decision-making structures have taken place over the last decade, and between which arrangements are now very different. The research discusses whether institutional change has had a beneficial or adverse effect, and whether any of the current structures provides a more effective framework for policy development and implementation. The results show that although the sites share a broadly common set of objectives there are differences in devolved responsibilities and in the extent to which various policy options are within the control of the bodies charged with transport policy delivery. The existence of several tiers of government, coupled with the many interactions required between these public sector bodies and the predominantly private sector public transport operators appears to create extra transactional barriers and impedes the implementation of the most effective measures for cutting congestion. There is, however, a compelling argument for the presence of an overarching tier of government to organise travel over a spatial scale compatible with that of major commuter patterns. The extent to which such arrangements currently appear to work is a function of the range of powers and the funding levels afforded to the co-ordinating organisation

Private Financing or Not, That is the Question: Lessons from the Light Rail Systems in Spain

The objective of this paper is to analyze if there is any difference between the light rail systems in Spain according to whether they have been carried out through public financing or private financing (totally or partially). The importance of this study lies in the fact that, for decades, the public–private partnership has been proposed as an alternative to public financing of public transport projects in order to obtain additional financial resources, reduce the public deficit, and increase efficiency. However, there are hardly any detailed studies describing how these initiatives have turned out. Therefore, the present study analyzes if there is any difference in the main variables explaining the performance of light rail projects in Spain depending on their source of funding can be found. For this, the relationship between variables related to design, operation and costs of the projects, and the percentage of private financing were statistically analyzed. As the most relevant conclusion, we underline the fact that the investment per passenger increases when financing is completely private. This would indicate that the most cost-effective lines, from a social standpoint, were financed totally or partially by the public administrations, whereas the least beneficial ones for society were assigned to private enterprises. This finding provides an advance in the knowledge of the consequences of private participation in the financing of public transport projects, indicating, moreover, that the biggest beneficiaries of this type of projects might be the construction companies and the politicians involvedThe authors would like to thank the ERDF of European Union for financial support via project ‘‘Herramienta para la evaluacio´n previa de infraestructuras de transporte pu´blico’’ (GGI3003IDIE). We also thank to Public Works Agency and Regional Ministry of Public Works and Housing of the Regional Government of Andalusia (AOPJA) and the Ministry of Education, Culture and Sports of the Government of Spain

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

Business models in rail infrastructure: explaining innovation

Policy decisions about the UK railway industry often draw on models and frameworks that treat technology and organisational processes as static and unchanging. As a result, policy makers often have limited understanding of how changes in policy will influence organisational knowledge, learning and the allocation of risk that subsequently affects innovation and system development. This paper applies a business model lens, focused on the mechanisms firms use to create and capture value, to connect policy decisions to subsequent changes in the organisation and industrial structure of the UK railway sector. By analysing innovation-related activity across several different governance structures, the paper highlights how policy impacts in network-based infrastructure sectors are mediated by business strategy, sometimes leading to unintended outcomes. The findings suggest that policy to improve the performance should focus upon coordination rather than just ownership. The application of a business model approach to complement existing economic and policy models in system analysis for policy decisions is advocated