Hydration and cooling in elite athletes: relationship with performance, body mass loss and body temperatures during the Doha 2019 IAAF World Athletics Championships

Purpose: To characterise hydration, cooling, body mass loss, and core (Tcore) and skin (Tsk) temperatures during World Athletics Championships in hot-humid conditions. Methods: Marathon and race-walk (20 km and 50 km) athletes (n=83, 36 women) completed a pre-race questionnaire. Pre-race and post-race body weight (n=74), Tcore (n=56) and Tsk (n=49; thermography) were measured. Results: Most athletes (93%) had a pre-planned drinking strategy (electrolytes (83%), carbohydrates (81%)) while ice slurry was less common (11%; p<0.001). More men than women relied on electrolytes and carbohydrates (91%–93% vs 67%–72%, p≤0.029). Drinking strategies were based on personal experience (91%) rather than external sources (p<0.001). Most athletes (80%) planned pre-cooling (ice vests (53%), cold towels (45%), neck collars (21%) and ice slurry (21%)) and/or midcooling (93%; head/face dousing (65%) and cold water ingestion (52%)). Menthol usage was negligible (1%–2%). Pre-race Tcore was lower in athletes using ice vests (37.5°C±0.4°C vs 37.8°C±0.3°C, p=0.024). Tcore (pre-race 37.7°C±0.3°C, post-race 39.6°C±0.6°C) was independent of event, ranking or performance (p≥0.225). Pre-race Tsk was correlated with faster race completion (r=0.32, p=0.046) and was higher in non-finishers (did not finish (DNF); 33.8°C±0.9°C vs 32.6°C±1.4°C, p=0.017). Body mass loss was higher in men than women (−2.8±1.5% vs −1.3±1.6%, p<0.001), although not associated with performance. Conclusion: Most athletes’ hydration strategies were pre-planned based on personal experience. Ice vests were the most adopted pre-cooling strategy and the only one minimising Tcore, suggesting that event organisers should be cognisant of logistics (ie, freezers). Dehydration was moderate and unrelated to performance. Pre-race Tsk was related to performance and DNF, suggesting that Tsk modulation should be incorporated into pre-race strategies

Hydration and cooling in elite athletes: relationship with performance, body mass loss and body temperatures during the Doha 2019 IAAF World Athletics Championships.

PURPOSE: To characterise hydration, cooling, body mass loss, and core (Tcore) and skin (Tsk) temperatures during World Athletics Championships in hot-humid conditions. METHODS: Marathon and race-walk (20 km and 50 km) athletes (n=83, 36 women) completed a pre-race questionnaire. Pre-race and post-race body weight (n=74), Tcore (n=56) and Tsk (n=49; thermography) were measured. RESULTS: Most athletes (93%) had a pre-planned drinking strategy (electrolytes (83%), carbohydrates (81%)) while ice slurry was less common (11%; p<0.001). More men than women relied on electrolytes and carbohydrates (91%-93% vs 67%-72%, p≤0.029). Drinking strategies were based on personal experience (91%) rather than external sources (p<0.001). Most athletes (80%) planned pre-cooling (ice vests (53%), cold towels (45%), neck collars (21%) and ice slurry (21%)) and/or mid-cooling (93%; head/face dousing (65%) and cold water ingestion (52%)). Menthol usage was negligible (1%-2%). Pre-race Tcore was lower in athletes using ice vests (37.5°C±0.4°C vs 37.8°C±0.3°C, p=0.024). Tcore (pre-race 37.7°C±0.3°C, post-race 39.6°C±0.6°C) was independent of event, ranking or performance (p≥0.225). Pre-race Tsk was correlated with faster race completion (r=0.32, p=0.046) and was higher in non-finishers (did not finish (DNF); 33.8°C±0.9°C vs 32.6°C±1.4°C, p=0.017). Body mass loss was higher in men than women (-2.8±1.5% vs -1.3±1.6%, p<0.001), although not associated with performance. CONCLUSION: Most athletes' hydration strategies were pre-planned based on personal experience. Ice vests were the most adopted pre-cooling strategy and the only one minimising Tcore, suggesting that event organisers should be cognisant of logistics (ie, freezers). Dehydration was moderate and unrelated to performance. Pre-race Tsk was related to performance and DNF, suggesting that Tsk modulation should be incorporated into pre-race strategies

CICO: A Credit-Based Incentive Mechanism for COoperative Fog Computing Paradigms

Fog computing is a key paradigm that brings together shared storage, low latency communication, and computation resources closer to users' end-devices. While most IoT services adopt a three-tier computing architecture, where fog nodes are always probed first before reaching a distant Cloud, collaboration across multi-stakeholder, multi-tenant fog providers remains unexplored. In this paper, we quantitatively highlight the gain which may arise if a collaborative fog computing paradigm is deployed. Next, we propose sol, an incentive-based collaborative mechanism for fog computing networks. solregulates a multi-stakeholder, multi-tenant cooperation among fog providers. We present a mathematical model and an experimental approach to make the case for such cooperation paradigm. © 2018 IEEE

Dynamiques de proximité et gestion des déchets : apllication à la mise en décharge

National audienceLes installations de stockage de déchets constituent un domaine d'application intéressant pour l'économie de la proximité : installations semi-désirables, elles font l'objet du principe de proximité au c½ur de la gouvernance territoriale des déchets tout en engendrant de fortes externalités locales ayant conduit le législateur à imposer une zone tampon périphérique. Toutefois, la notion de proximité permet d'aller plus loin en intégrant dans l'analyse l'origine géographique des déchets et de leurs producteurs, dont la proximité cognitive avec les riverains des installations est d'autant plus faible que le bassin-versant des déchets est étendu. Concilier effets d'échelle et proximités afin d'intégrer la nécessaire mise en décharge dans le métabolisme d'un territoire nécessite de trouver un équilibre acceptable par tous entre producteurs urbains et récepteurs ruraux des déchets, et porté par des acteurs suffisamment légitime

Conflits autour des ISDND. Quelles conséquences pour la gouvernance territoriale des déchets ?

National audienceLes installations de stockage de déchets non dangereux (ISDND) constituent des usages des sols généralement non souhaités par les riverains et sont font donc souvent l'objet de conflits rendant la gouvernance territoriale des déchets délicate. A partir d'une enquête sur les conflits en Ile-de-France et d'une analyse de certains d'entre eux, nous mettons en évidence une montée en généralité des problématiques locales posant des questions d'équité territoriale et d'application du principe de proximité en gestion des déchets, et même de définition de l'intérêt général en fonction des échelles territoriales de gestion. La taille des installations n'explique pas nécessairement la conflictualité alors que la conflictualité peut expliquer la taille finale et la concentration spatiale des installations, d'autant que les situations sont souvent gérées dans l'urgence

Principes(s) de proximité(s) en gestion des déchets : Réflexions à partir d'un projet de décharge

International audienceIl est bien connu que les décharges sont une des infrastructures les plus problématiques quant on considère les questions d'acceptation et de localisation des infrastructures. Nous proposons une approche fondée sur la notion polysémique mais conceptuellement unificatrice de proximité, en nous inspirant d'un cas réel de projet de décharge. Les relations entre acteurs aux intérêts divers (exploitant porteur du projet, producteurs de déchets, riverains agriculteurs et résidents, élus locaux) sont analysées à l'aune de ce concept. La conflictualité apparait en général inévitable lors de projets de nouvelles installations. Elle peut faire évoluer des problématiques amont, en lien avec la soutenabilité des métabolismes industriels et urbains mais aussi favoriser rentes et injustices environnementales

Making the Case For Computational Offloading in Mobile Device Clouds

It is common practice for mobile devices to offload computationally heavy tasks off to a cloud, which has greater computational resources. We consider an environment in which computational offloading is made among mobile devices. We call such an environment a mobile device cloud (MDC). In this work, we first highlight the gain in computation time and energy consumption that can be achieved by offloading tasks to nearby devices inside a mobile device cloud. We do this by emulating network conditions that exist for different communication technologies provided by modern mobile devices. We then present a platform that allows creation and offloading of tasks by a mobile devices to nearby devices. Such a platform consists of an API, an accompanying Android application deployable across MDC devices, and a test bed to measure power being consumed by a mobile device. Finally, we create and utilize a testbed, which consists of four Android devices and energy measurement equipment, in order to validate our intuitions and qualify the gain in time and energy which we deduced from the emulation experiments. Using this test bed we show up t

Hardware Implementation of FTC of Induction Machine on FPGA

In this paper, a new design method of Direct Torque Control using Space Vector Modulation (DTC-SVM) of an Induction Machine (IM), which is based on Fault Tolerant Control (FTC) is proposed. Due to its complexity, the FTC implemented on a microcontroller and a Digital Signal Processor (DSP) is characterized by a calculating delay. To solve this problem, an alternative digital solution is used, based on the Field Programmable Gate Array (FPGA), which is characterized by a fast processing speed. However, as an FPGAs increase in size, there is a need for improved productivity, and this includes new design flows and tools. Xilinx System Generator (XSG) is a high-level block-based design tool that offers bit and cycle accurate simulation. This tool can automatically generate the Very High-Density Logic (VHDL) code without resorting to a tough programming, without being obliged to do approximations and more we can visualize the behavior of the machine before implementation which is very important for not damage our machine. Simulation and experimental results using Hardware In the Loop (HIL) of the FTC based DTC-SVM is compared with those of the conventional DTC. The comparison results illustrate the reduction in the torque and stator flux ripples. Our purpose is to reveal our algorithm efficiency and to show the Xilinx Virtex V FPGA performances in terms of execution time.

Hardware software co-simulation of a digital EMI filter using Xilinx system generator

Mitigation of electromagnetic inference (EMI) is currently a challenge for scientists and designers in order to cope with electromagnetic compatibility (EMC) compliance in switching mode power supply (SMPS) and ensure the reliability of the whole system. Standard filtering techniques: passive and active ones present some insufficiency in terms of performance at high frequencies (HF) because analog components would no longer be controllable and this is mainly due to their parasitic elements. So developing EMI digital filters is very interesting, especially with the embedment of a machine control system on a field programmable gate array (FPGA) chip. In this paper, we present a design of an active digital EMI filter (ADF) to be integrated in a drive train system of an electric vehicle (EV). Hardware design as well as FPGA implementation issues have been presented to prove the efficiency of the developed digital filtering structure