International Society of Sports Nutrition Position Stand: Probiotics.

Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of probiotic supplementation to optimize the health, performance, and recovery of athletes. Based on the current available literature, the conclusions of the ISSN are as follows: 1)Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host (FAO/WHO).2)Probiotic administration has been linked to a multitude of health benefits, with gut and immune health being the most researched applications.3)Despite the existence of shared, core mechanisms for probiotic function, health benefits of probiotics are strain- and dose-dependent.4)Athletes have varying gut microbiota compositions that appear to reflect the activity level of the host in comparison to sedentary people, with the differences linked primarily to the volume of exercise and amount of protein consumption. Whether differences in gut microbiota composition affect probiotic efficacy is unknown.5)The main function of the gut is to digest food and absorb nutrients. In athletic populations, certain probiotics strains can increase absorption of key nutrients such as amino acids from protein, and affect the pharmacology and physiological properties of multiple food components.6)Immune depression in athletes worsens with excessive training load, psychological stress, disturbed sleep, and environmental extremes, all of which can contribute to an increased risk of respiratory tract infections. In certain situations, including exposure to crowds, foreign travel and poor hygiene at home, and training or competition venues, athletes' exposure to pathogens may be elevated leading to increased rates of infections. Approximately 70% of the immune system is located in the gut and probiotic supplementation has been shown to promote a healthy immune response. In an athletic population, specific probiotic strains can reduce the number of episodes, severity and duration of upper respiratory tract infections.7)Intense, prolonged exercise, especially in the heat, has been shown to increase gut permeability which potentially can result in systemic toxemia. Specific probiotic strains can improve the integrity of the gut-barrier function in athletes.8)Administration of selected anti-inflammatory probiotic strains have been linked to improved recovery from muscle-damaging exercise.9)The minimal effective dose and method of administration (potency per serving, single vs. split dose, delivery form) of a specific probiotic strain depends on validation studies for this particular strain. Products that contain probiotics must include the genus, species, and strain of each live microorganism on its label as well as the total estimated quantity of each probiotic strain at the end of the product's shelf life, as measured by colony forming units (CFU) or live cells.10)Preclinical and early human research has shown potential probiotic benefits relevant to an athletic population that include improved body composition and lean body mass, normalizing age-related declines in testosterone levels, reductions in cortisol levels indicating improved responses to a physical or mental stressor, reduction of exercise-induced lactate, and increased neurotransmitter synthesis, cognition and mood. However, these potential benefits require validation in more rigorous human studies and in an athletic population

Simulation hybride des réseaux IP-DiffServ-MPLS multi-services sur environnement d'exécution distribuée

Technology used for telecommunication packet-switched networks is in constant evolution. Current trends are directed towards mutualisation of voice and data services and of their infrastructures and technologies (IP/MPLS networks and QoS in Internet). Analytic modelling and event-driven simulations are the common ways to evaluate performance of these networks. But event-driven simulations require huge processing time whereas models resulting from analytic methods can lack of accuracy. This thesis defines a framework called Distributed Hybrid Simulation, which rigorously combines the differential traffic theory and event driven simulations. In a first technique, network resources are partitioned in domains. Some of them are simulated by events, and the others are modelled by numerically integrated differential equations. The other technique allows propagation of event-driven traffics over networks modelled by differential equations. Thus Hybrid Simulation pushes back the theoretical limits of analytic modelling and allows one to design general performance evaluation models and less time-consuming software. A Hybrid simulator prototype has been developed. One can model Internet Diffserv and MPLS routers, TCP protocols and various multimedia traffic sources (Audio, Video). To even more reduce processing time, the simulator can be parallelized. So a new communication kernel has been designed for the LANDA environment. It proposes a MPI software library that allows a latency-efficient and bandwidth-efficient use of several communication interfaces and SMP shared memory.La technologique utilisée dans les réseaux de télécommunication à commutation de paquets est en développement permanent. La tendance actuelle est orientée vers la mutualisation des services voix et données, de leurs infrastructures et des techniques associées (réseaux IP/MPLS, QoS dans Internet). Les méthodes classiques utilisées pour l'évaluation de performances des ces réseaux sont la modélisation analytique et la simulation événementielle. La simulation événementielle requiert des temps de calcul prohibitifs, tandis que les modèles issus des méthodes analytiques manquent parfois de précision. Le travail présenté dans cette thèse définit un cadre de modélisation appelé Simulation Hybride Distribuée qui combine de manière rigoureuse la théorie différentielle du trafic et la simulation événementielle. Dans une première technique, les ressources du réseau sont partitionnées en domaines dont certains sont simulés par événements, et les autres sont modélisés par des équations intégrées numériquement. La seconde technique proposée permet la circulation de trafics simulés par événements sur les ressources du réseau modélisées par des équations. La simulation hybride permet ainsi de prolonger la modélisation analytique au-delà de ses limites théoriques. Elle permet également de concevoir des modèles d'évaluation de performances très généraux et de développer des logiciels plus performants en temps de calculs. Un prototype de simulateur hybride a été conçu. Il permet de modéliser précisément des routeurs Internet Diffserv et MPLS, le protocole TCP ainsi que diverses sources de trafic multimédia (Audio, Vidéo). Pour réduire les temps de calcul, le simulateur peut être parallélisé. En ce sens, un nouveau noyau de communication de l'environnement de parallélisme LANDA a été conçu. Il offre une bibliothèque à la norme MPI et permet d'utiliser simultanément et efficacement (latence, bande passante) plusieurs media de communication haut-débit ainsi que la mémoire commune S MP

Simulation hybride des réseaux IP-DiffServ-MPLS multi-services sur environnement d'exécution distribuée

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

LaasNetExp: a generic polymorphic platform for network emulationand experiments

International audienceNetwork experiments are essential for assessing and validating new networking technologies, architectures and protocols. These assessments have long been performed using network simulators. But it clearly appeared that the results got in simulations cannot be reproduced in real environment. Emulators can hardly integrate accurate models of all networking components, end host operating systems and applications what leads to not realistic simulations very often. Therefore, some work has been issued for developing real experiment platform and network emulators. This paper addresses the motivations that raised the design and development of such an experimental platform at LAAS – laasnetexp – and describes its constituting features and components. It is in particular detailed how experimental conditions can be fully controlled for reproducible and easy to analyze experiments. Last, this paper describes how realistic conditions can be set-up in experiments by using the results of actual Internet and Internet traffic characterization, analysis and modeling. Such information helps to realistically configure emulators as well as define realistic traffic generators. The realism of such experiments is illustrated as a demonstration of the interest of laasnetexp for networking research

LaasNetExp : une plateforme expérimentale pour l'émulation et les tests de réseaux

L'expérimentation en réseaux est incontournable pour évaluer et valider de nouvelles technologies, architectures et protocoles de communication. Il s'avère que les résultats obtenus à partir de simulations sont la plupart du temps irréalistes, les simulateurs ne pouvant pas intégrer tous les modèles de comportement des composants réseaux, des systèmes opératoires et des applications des machines d'extrémité. Des travaux autour de l'émulation et de l'expérimentation réelle en réseaux ont donc vu le jour. Ce papier présente les motivations et besoins qui ont conduit à la mise en place d'une telle plate-forme expérimentale au LAAS - LaasNetExp - et décrit ses principes de conception. L'article détaille comment les conditions expérimentales peuvent être contrôlées pour des expériences reproductibles et faciles à analyser. L'article montre aussi comment des conditions expérimentales réalistes configuration des émulateurs et générateurs de trafics) peuvent être mise en oeuvre à partir des résultats de caractérisation et analyse du trafic Internet. Cet article évalue le réalisme des expérimentations ainsi obtenues

STRATÉGIE DE CONCEPTION AMÉLIORÉE POUR L'AUTOCOLLIMATION MÉSOSCOPIQUE

National audienceNous présentons un modèle multi-échelle de cristal photonique mésoscopique (MPhC) assurant une transmission totale, sans déformation (MSC), de l'énergie. En privilégiant le contrôle des réflectivités aux interfaces, un ensemble complet des MPhC assurant une MSC est facilement obtenu. Ce modèle ouvre la voieà l'étude des MPhC en incidence oblique

Selecting Machine Learning Models to Support the Design of Al/CuO Nanothermites

International audienceNovel properties associated with nanothermites have attracted great interest for several applications, including lead-free primers and igniters. However, the prediction of quantitative structure-energetic performance relationships are still challenging. This study investigates machine learning methods as tools to surrogate complex physical models to design novel nanothermites with optimized burning rates chosen for energetic performance. The stud

Enhanced design strategy for Mesoscopic Self-Collimation

International audienceMesoscopic photonic crystals (MPhC) are composed of alternating photonic crystal slabs (PhC) and homogeneous material. MPhC structures combine PhC dispersive properties (self-collimation and slow light, among others) with reflectivity control (Bragg mirrors). One of the most studied properties of MPhC is mesoscopic selfcollimation (MSC). MSC occurs when PhC dispersion properties compensate the natural divergence of light in homogeneous material [1]. However, MSC is only visible if the energy properly propagates throughout the structure, it is thus crucial to control undesirable reflections at each interface. Different methods, relying on complex Fourier modal analysis [2], allow reflectivity control using an impedance-based approach such as half-holes or comet-like holes between each interface. These methods have fabrication limitations (not circular holes) and may need long and complex calculations. We propose a method based on a fast and simple multiscale approach. In constrast to [3] we prioritize perfect antireflection at the different interfaces, instead of perfect self-collimation. At the µm-scale, we first model the MPhC as a multilayer Bragg structure. By solving simple Bragg equations we determine a first set of parameters ensuring perfect antireflection. At the nm-scale, we then take into account the PhC dispersion properties to search for MSC solutions within the first set of parameters. With this approach, we obtain a complete set of MPhC geometries that ensures reflectivity control and correct MSC (i.e. low beam divergence), without the need for long numerical simulations. To validate our model, we use FDTD [4] simulations to study light propagation through the previously determined MPhC (Figures 1b, 1c, 1d)