Influence du changement de l'angle d'incidence entre le vecteur gravitationnel terrestre et l'axe sagittal du rachis sur les performances posturales statiques et dynamiques d'un individu

Le vecteur gravitationnel conditionne chacune des activités de l'Homme et en particulier son aptitude à s'ériger et contrôler sa posture et son équilibre. La manière (l'incidence) dont ce vecteur s'exerce sur le grand axe du corps dépend de la posture de l'individu. L'Homme partage sa vie entre trois postures fondamentales : debout, assise ou couchée. Ce travail a consisté à mesurer la posture en position debout après avoir modifié la durée et la qualité des deux autres postures. Deux situations expérimentales ont été utilisées : une modification de la posture assise en proposant un mobilier ergonomique aux mêmes élèves au cours de la scolarité de la 6ème à la 3ème et une modification de la posture couchée en plaçant des sujets en décubitus anti-orthostatique (- 6°) pendant 60 jours. On observe des modifications posturales : le mobilier ergonomique améliore les performances par rapport au mobilier conventionnel et permet d'atténuer la perte de performances induite par la puberté ; l'alitement de longue durée entraîne des perturbations du contrôle postural comparables à celles observées au cours des vols spatiaux. En position assise il faut donc promouvoir, pendant les années collège, l'utilisation d'un mobilier ergonomique. Si une position couchée doit être maintenue pendant une longue période (raison médicale) il faut alors mettre en place des méthodes prophylactiques (exercices physiques) pour lutter contre ses effets délétères. Ceci est valable, aussi, pour les séjours de longue durée en microgravité (vols spatiaux) afin de conserver au contrôle moteur toute son efficacité notamment lors du retour sur terre.The gravitational loading governs all the Human activities and particularly the ability to stand and control balance. The angle of incidence of the gravitational vector on the main body axis depends on the way the subject stands. The three more important postures in Human life are: standing, sitting or lying. This study consists on analyzing the postural control in a stand up position after a modification of the quality and the duration of the two others positions. Two experimental conditions have been used : a modification of the sitting position by the use of ergonomic furnitures for the same students from the 6th to the 3thd degree and a modification of the lying position by placing subjects on a head-down-bed-rest (antiorthostatic position, -6°) during 60 days. We can notice postural modifications: comparing to the conventional furnitures, the ergonomic furnitures improve the postural performances and allowed to minimize the decrease of performances due to the puberty; the long duration bed-rest involve a postural control perturbation comparable to what has been observed during space flights. So, it is important, in sitting position, to promote, during the student life, the utilization of ergonomic furnitures and if a bed rest position has to be maintain during a long period (for medical reasons) prophylactic methods (such as physical exercises) have to be preconized in order to prevent the deconditioning effects. The same treatment can also be applied to the long duration missions in microgravity (space flights) in order to allowed all the efficiency of the motor control in particular for the return to Earth

Influence du changement de l'angle d'incidence entre le vecteur gravitationnel terrestre et l'axe sagittal du rachis sur les performances posturales statiques et dynamiques d'un individu

Le vecteur gravitationnel conditionne chacune des activités de l'Homme et en particulier son aptitude à s'ériger et contrôler sa posture et son équilibre. La manière (l'incidence) dont ce vecteur s'exerce sur le grand axe du corps dépend de la posture de l'individu. L'Homme partage sa vie entre trois postures fondamentales : debout, assise ou couchée. Ce travail a consisté à mesurer la posture en position debout après avoir modifié la durée et la qualité des deux autres postures. Deux situations expérimentales ont été utilisées : une modification de la posture assise en proposant un mobilier ergonomique aux mêmes élèves au cours de la scolarité de la 6ème à la 3ème et une modification de la posture couchée en plaçant des sujets en décubitus anti-orthostatique (- 6) pendant 60 jours. On observe des modifications posturales : le mobilier ergonomique améliore les performances par rapport au mobilier conventionnel et permet d'atténuer la perte de performances induite par la puberté ; l'alitement de longue durée entraîne des perturbations du contrôle postural comparables à celles observées au cours des vols spatiaux. En position assise il faut donc promouvoir, pendant les années collège, l'utilisation d'un mobilier ergonomique. Si une position couchée doit être maintenue pendant une longue période (raison médicale) il faut alors mettre en place des méthodes prophylactiques (exercices physiques) pour lutter contre ses effets délétères. Ceci est valable, aussi, pour les séjours de longue durée en microgravité (vols spatiaux) afin de conserver au contrôle moteur toute son efficacité notamment lors du retour sur terre.The gravitational loading governs all the Human activities and particularly the ability to stand and control balance. The angle of incidence of the gravitational vector on the main body axis depends on the way the subject stands. The three more important postures in Human life are: standing, sitting or lying. This study consists on analyzing the postural control in a stand up position after a modification of the quality and the duration of the two others positions. Two experimental conditions have been used : a modification of the sitting position by the use of ergonomic furnitures for the same students from the 6th to the 3thd degree and a modification of the lying position by placing subjects on a head-down-bed-rest (antiorthostatic position, -6) during 60 days. We can notice postural modifications: comparing to the conventional furnitures, the ergonomic furnitures improve the postural performances and allowed to minimize the decrease of performances due to the puberty; the long duration bed-rest involve a postural control perturbation comparable to what has been observed during space flights. So, it is important, in sitting position, to promote, during the student life, the utilization of ergonomic furnitures and if a bed rest position has to be maintain during a long period (for medical reasons) prophylactic methods (such as physical exercises) have to be preconized in order to prevent the deconditioning effects. The same treatment can also be applied to the long duration missions in microgravity (space flights) in order to allowed all the efficiency of the motor control in particular for the return to Earth.TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Video News release (A-roll) International Conference on Translational Research in Radio-Oncology and Physics for Health in Europe

Video News Release (A-roll) accompanying the Press Release announcing the International Conference on Translational Research in Radio-Oncology and Physics for Health in Europe, organized by CERN at the International Conference Centre Geneva from February 27 to March 2

VNR (b-roll) ICTR-PHE 2012

Video News Release (B-roll)accompanying the press release announcing the ICTR-PHE 2012 conference (International Conference on Translational Research in Radio-Oncology and Physics for Health in Europe)organized by CERN from Feb 27 to March 2, 2012 at the International Conference Centre Geneva (CICG)

Peptide-Based Nanoparticles to Rapidly and Efficiently “Wrap ’n Roll” siRNA into Cells

International audienc

Village Settlements in Mountainous Tropical Areas, Hotspots of Fecal Contamination as Evidenced by Escherichia coli and Stanol Concentrations in Stormwater Pulses

International audienceFecal bacteria in surface water may indicate threats to human health. Our hypothesis is that village settlements in tropical rural areas are major hotspots of fecal contamination because of the number of domestic animals usually roaming in the alleys and the lack of fecal matter treatment before entering the river network. By jointly monitoring the dynamics of Escherichia coli and of seven stanol compounds during four flood events (July–August 2016) at the outlet of a ditch draining sewage and surface runoff out of a village of Northern Lao PDR, our objectives were (1) to assess the range of E. coli concentration in the surface runoff washing off from a village settlement and (2) to identify the major contributory sources of fecal contamination using stanol compounds during flood events. E. coli pulses ranged from 4.7 × 104 to 3.2 × 106 most probable number (MPN) 100 mL–1, with particle-attached E. coli ranging from 83 to 100%. Major contributory feces sources were chickens and humans (about 66 and 29%, respectively), with the highest percentage switching from the human pole to the chicken pole during flood events. Concentrations indicate a severe fecal contamination of surface water during flood events and suggest that villages may be considered as major hotspots of fecal contamination pulses into the river network and thus as point sources in hydrological models

Experimental and modelling evidence of short-term effect of raindrop impact on hydraulic conductivity and overland flow intensity

International audienceTropical montane areas of Southeast Asia are exposed to high-intensity rainfall during the monsoon period. This is particularly problematic in areas where soils on steep slopes are cultivated as it can lead to heavy runoff, high soil erosion, and water pollution. The objective of this paper is to analyse the effect of the impact of raindrops on the dynamics of runoff on such steep fields. Experiments under simulated rainfall were performed at the plot scale (1 m2) to quantify water export from the surface of upland agricultural soils during overland flow events. Four 1 m2 plots were divided in duplicated treatment groups: (a) control with no amendments, and (b) amended with pig manure. Each plot was divided into two 0.5 m2 rectangular subplots. One subplot was designated as a rain splash treatment; the other sub-plot was covered with a 2 mm grid size wire screen that was located 12 cm above the soil surface. The purpose of the screen was to break the raindrops into fine droplets and to reduce fall height in order to drastically reduce their kinetic energy. Runoff was measured for each sub-plot. The results show that raindrop impact drastically enhances runoff generation on both bare soils and on manure amended soils. When the impact of raindrops was limited by screening, runoff was higher on amended soils than on bare soils.The temporal evolution of runoff was correctly modelled using a soil hydraulic conductivity that exponentially decreases over time of exposure to rainfall. Both experimental and modelling results showed that droplet energy induces a rapid evolution of the hydraulic properties of the soil surface due to crusting, resulting in a reduction of hydraulic conductivity and a concomitant increase in runoff rate

Experimental and modelling evidence of splash effects on manure borne Escherichia coli washoff

International audienceIn tropical montane South-East Asia, recent changes in land use have induced increased runoff, soil erosion and in-stream suspended sediment loads. Land use change is also contributing to increased microbial pathogen dissemination and contamination of stream waters. Escherichia coli (E. coli) is frequently used as an indicator of faecal contamination. Field rain simulations were conducted to examine how E. coli is exported from the surface of upland, agricultural soils during runoff events. The objectives were to characterize the loss dynamics of this indicator from agricultural soils contaminated with livestock waste, and to identify the effect of splash on washoff. Experiments were performed on nine 1 m2 plots, amended or not with pig or poultry manure. Each plot was divided into two 0.5 m2 sub-plots. One of the two sub-plots was protected with a mosquito net for limiting the raindrop impact effects. Runoff, soil detachment by raindrop impact and its entrainment by runoff, and E. coli loads and discharge were measured for each sub-plot. The results show that raindrop impact strongly enhances runoff generation, soil detachment and entrainment and E. coli export. When the impact of raindrops was reduced with a mosquito net, total runoff was reduced by more than 50%, soil erosion was on average reduced by 90% and E. coli export from the amended soil surface was on average 3 to 8 times lower. A coupled physics-based approach was performed using the Cast3M platform for modelling the time evolutions of runoff, solid particles detachment and transfer and bacteria transport that were measured for one of the nine plots. After estimation of the saturated hydraulic conductivity, soil erodibility and attachment rate of bacteria, model outputs were consistent with measured runoff coefficients, suspended sediment and E. coli loads. This work therefore underlines the need to maintain adequate vegetation at the soil surface to avoid the erosion and export of soil borne potential pathogens towards downstream aquatic systems

Quantifying the effect of overland flow on Escherichia coli pulses during floods: use of a tracer-based approach in an erosion-prone tropical catchment

International audienceBacterial pathogens in surface waters threaten human health. The health risk is especially high in developing countries where sanitation systems are often lacking or deficient. Considering twelve flash-flood events sampled from 2011 to 2015 at the outlet of a 60-ha tropical montane headwater catchment in Northern Lao PDR, and using Escherichia coli as a fecal indicator bacteria, our objective was to quantify the contributions of both surface runoff and sub-surface flow to the in-stream concentration of E. coli during flood events, by (1) investigating E. coli dynamics during flood events and among flood events and (2) designing and comparing simple statistical and mixing models to predict E. coli concentration in stream flow during flood events. We found that in-stream E. coli concentration is high regardless of the contributions of both surface runoff and sub-surface flow to the flood event. However, we measured the highest concentration of E. coli during the flood events that are predominantly driven by surface runoff. This indicates that surface runoff, and causatively soil surface erosion, are the primary drivers of in-stream E. coli contamination. This was further confirmed by the step-wise regression applied to instantaneous E. coli concentration measured in individual water samples collected during the flood events, and by the three models applied to each flood event (linear model, partial least square model, and mixing model). The three models showed that the percentage of surface runoff in stream flow was the best predictor of the flood event mean E. coli concentration. The mixing model yielded a Nash-Sutcliffe efficiency of 0.65 and showed that on average, 89% of the in-stream concentration of E. coli resulted from surface runoff, while the overall contribution of surface runoff to the stream flow was 41%. We also showed that stream flow turbidity and E. coli concentration were positively correlated, but that turbidity was not a strong predictor of E. coli concentration during flood events. These findings will help building adequate catchment-scale models to predict E. coli fate and transport, and mapping the related risk of fecal contamination in a global changing context

Post-stroke remodeling processes in animal models and humans.

International audienceAfter cerebral ischemia, events like neural plasticity and tissue reorganization intervene in lesioned and non-lesioned areas of the brain. These processes are tightly related to functional improvement and successful rehabilitation in patients. Plastic remodeling in the brain is associated with limited spontaneous functional recovery in patients. Improvement depends on the initial deficit, size, nature and localization of the infarction, together with the sex and age of the patient, all of them affecting the favorable outcome of reorganization and repair of damaged areas. A better understanding of cerebral plasticity is pivotal to design effective therapeutic strategies. Experimental models and clinical studies have fueled the current understanding of the cellular and molecular processes responsible for plastic remodeling. In this review, we describe the known mechanisms, in patients and animal models, underlying cerebral reorganization and contributing to functional recovery after ischemic stroke. We also discuss the manipulations and therapies that can stimulate neural plasticity. We finally explore a new topic in the field of ischemic stroke pathophysiology, namely the brain-gut axis