Effect of melatonin ingestion on physical performance, metabolic responses, and recovery after an intermittent training session

Objectives Fatigue is a limiting factor for sport performance. For this reason, optimal recovery after training is just as critical as the training program itself, if not more. Indeed, there is a need for strategies that can facilitate recovery after training, and one such strategy is the ingestion of supplements like melatonin (MEL). This study aimed to evaluate if MEL intake could improve recovery of athletes after an intermittent training session (ITS). Methods Fifteen elite female athletes (17.4 ± 0.4 years, 76.4 ± 5.6 kg, 1.76 ± 0.04 m; mean ± standard deviation) participated in two testing campaigns. During each period, they performed a battery of physical and cognitive tests before and after an ITS, as well as after ingesting MEL (6 mg tablet) or placebo in a randomized design. The ITS comprised the modified agility T-test, squat jump, counter movement jump, maximum standing ball-throw velocity test, maximum jump ball-throw velocity test, and 20-m sprint. Oral temperature (OT) and vigilance were evaluated before and after the ITS. Rating of perceived exertion (RPE), blood lactate [La], and glucose [Gl] were recorded after each ITS. Results Short-term performance, recovery of physical performance, and OT were not affected by MEL ingestion after the ITS. Moreover, MEL did not affect cognitive performance or RPE scores after the ITS. However, [La] and [Gl] (p < 0.05 for both) were decreased after MEL ingestion. Conclusion: MEL has no effect on the recovery of physical performance but may affect glucose utilization and lactate metabolism during the team-handball training session

Value of monitoring in asset management: A social costbenefit analysis approach

We present a framework to investigate new monitoring techniques for infrastructures and assess their potential value for the network management. This framework is based on a social cost benefit analysis tool that aims to (i) assist decision makers in selecting and developing cost-effective new monitoring techniques and (ii) provide managers with socially optimal maintenance and rehabilitation strategies that take into account output from these monitoring systems. Potential value of monitoring consists mainly in enabling condition-based strategies and providing more accurate and relevant information that should result in more cost-effective strategies. Monitoring provides information about either the structure degradation level or its environment. The condition of the structure is represented by a set of technical performance indicators that reflect its degradation level and are linked to a set of end-user service levels. Finally, the end-user service levels are valuated to optimize the cost and benefits of maintenance and rehabilitation strategies. Main feature of the tool we develop is to enable optimal, dynamic and reliabilitybased decisions that are reviewed and updated every time a new relevant information is available. Transition probabilities to predict future deterioration levels are estimated and updated using monitoring data to assess risks and optimize its expected cost. Moreover, the derived strategies are socially optimal and take into account indirect impacts of degradations and M&R strategies on the society and the environment. This is done by consideration and valuation of end-user service levels. We use Markov decision processes which are an appropriate framework for decision-making under uncertainty to incorporate reliability and risk measures within the optimization problem. Copyright © 2013, AIDIC Servizi S.r.l

An eco-friendly epoxy polymer binder for the treatment of Tunisian harbor sediments: Laboratory investigations for beneficial reuse

International audienceThe management of dredged sediments poses serious environmental and economic problems because of their geochemical properties and in particular their pollutant content. In this research, marine sediments from Tunisian harbors were collected to study their beneficial reuse as construction materials using an eco-friendly polymer binder. Experimental investigations include the determination of physicochemical, mineralogical, and environmental parameters of sediments from the Sidi Mansour and Sidi Youssef areas in Tunisia. Prismatic mortar samples (4 × 4 × 16 cm) were prepared at laboratory scale using normalized sand and epoxy resin. Then their composition was modified by including a sediment fraction in the substitution of sand at rates ranging from 10 to 50% in dry mass. After a 7-day curing period, mortar samples were submitted to mechanical, physicochemical, and environmental analyses. Mortar samples including sediment fractions displayed lower strength than sand mortar used as control. This result is explained by the increase of porosity values in the mortar samples when sediment samples were incorporated. A positive relationship between porosity and compressive strength values was evidenced, suggesting that the compactness of granular skeleton could play an important role in the preparation of materials. From an environmental point of view, the mortar samples containing sediment fractions showed relatively low leaching levels, which confirms their suitability for the manufacturing of construction materials. © The Author(s) 2020