Journal of Next-Generation Research 5.0
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Spontaneous change from seated to standing cycling position with increasing power is associated with a minimization of cost functions
No full textInternational audienceSpontaneous changes of movement patterns may allow to elucidate which criteria influence movement pattern preferences. However, the factors explaining the sit-stand transition in cycling are unclear. This study investigated if biomechanical and/or muscle activation cost functions could predict the power at which the spontaneous sit-stand transition occurs. Twenty-five participants performed an incremental test leading to the sit-to-stand transition, and subsequent randomized pedaling trials at 20 to 120% of the transition power in seated and standing position. A Moment Cost Function based on lower limbs net joint moments and two Electromyographic Cost Functions based on EMG data were defined. All cost functions increased with increasing crank power (p < 0.001) but at different rates in the seated and standing positions. They had lower values in the seated position below the transition power and lower values in the standing position above the transition power (p < 0.05). These results suggest that spontaneous change of position observed in cycling with increasing crank power represents an optimal choice to minimize muscular efforts. These results support the use of simple cost functions to define optimal settings in cycling and to assess the cost of cycling during short-term efforts
Effect of type 2 diabetes on energy cost and preferred speed of walking
No full textInternational audiencePurposeAlthough walking is the most commonly recommended activity for patients with type 2 diabetes (T2D), these patients walk daily less than their healthy peers and adopt a lower self-selected speed. It has been suggested that gait alterations observed in this population could be responsible for a higher metabolic rate (MR) during walking. Thus, the aim of this study was to compare relationship between MR, the energy cost of walking per unit of distance (Cw) and self-selected walking speed in T2D patients and healthy individuals.MethodsWe measured metabolic and spatiotemporal parameters for 20 T2D patients and 20 healthy control subjects, while they walked on a treadmill at different speeds (0.50–1.75 m s−1) using a breath-by-breath gas analyzer and an inertial measurement unit, respectively.ResultsNet MR was 14.3% higher for T2D patients on average across all speeds, and they preferred to walk 6.8% slower at their self-selected compared with their non-diabetics counterparts (1.33 vs. 1.42 m s−1, respectively; p = 0.045). Both groups naturally walked at a self-selected speed close to their minimum gross Cw per distance, with similar values of minimum gross Cw (3.53 and 3.32 J kg−1 m−1 in T2D patients and control subjects, respectively).ConclusionWhen compared with healthy subjects, T2D patients walk with a higher MR at any given speed. Thus, the slower self-selected speed observed in T2D patients seems to correspond to the speed at which their gross energy cost per distance was minimized and allows T2D patients to walk at the same intensity than healthy subjects
Development of a Novel Integrated Approach to Monitor Processing of Cassava Roots into Gari: Macroscopic and Microscopic Scales
No full textGari is a key staple food in several western African countries. This is a cassava traditional semolina obtained after peeling, rasping, fermentation, pressing, sieving, and roasting (cooking/drying). The process of gari production is artisanal and relies on human know-how, and the final properties of gari are highly dependent on the human skills. So as to understand the combined effect of the various transformation steps on the final quality of gari, the main objective of this work was to develop a lab-scale integrated approach to follow the transformation of the product characteristics during the process using macroscopic (water content, solid volume fraction, and particles size) and microscopic (physicochemical and biochemical) responses. At the microscopic level, pressing is a key step insofar as it induces the draining of many soluble compounds (especially the toxic cyanogenic compounds). At the macroscopic level, despite the strong similarity in median diameters of the intermediate and final products, two distinct agglomeration mechanisms occurred during the pressing/sieving and the roasting. These mechanisms highlight the structuration of the product at two different scales and at two different moments. Finally, results showed a high swelling capacity for fermented gari. The approach developed in this work will make it possible to identify the robust mechanisms, i.e., those little affected by a change in scale or in operating conditions. This identification will thereafter allow to distinguish unit operations, fairly easy to mechanize, from those requiring strict control to achieve the final product quality sought
Two-year operation of the lidar 1200: from fine-scale tropospheric structures to lower stratospheric water vapor detection
No full textInternational audienceThe 2-year lidar water vapor database (November 2013 - October 2015) of the Maïdo Observatory (Reunion Island / 21°S,55.5°E) is now calibrated. The performance of the lidar to provide accurate vertical structures are shown to be good. The ability of measuring quantities of a few ppmv in the lower stratosphere is demonstrated up to 22 km (based on Cryogenic Frostpoint Hygrometer sondes/lidar profiles comparisons) for an integration time period of 48 hours and a vertical resolution of 1.3 km
Finding the right fit: Comparative cetacean distribution models using multiple data sources and statistical approaches
No full textInternational audienceAim: Accurate predictions of cetacean distributions are essential to their conservation but are limited by statistical challenges and a paucity of data. This study aimed at comparing the capacity of various statistical algorithms to deal with biases commonly found in nonsystematic cetacean surveys and to evaluate the potential for citizen science data to improve habitat modelling and predictions. An endangered population of humpback whales (Megaptera novaeangliae) in their breeding ground was used as a case study. Location: New Caledonia, Oceania. Methods: Five statistical algorithms were used to model the habitat preferences of humpback whales from 1,360 sightings collected over 14 years of nonsystematic research surveys. Three different background sampling approaches were tested when developing models from 625 crowdsourced sightings to assess methods accounting for citizen science spatial sampling bias. Model evaluation was conducted through cross-validation and prediction to an independent satellite tracking dataset. Results: Algorithms differed in complexity of the environmental relationships modelled , ecological interpretability and transferability. While parameter tuning had a great effect on model performances, GLMs generally had low predictive performance , SVMs were particularly hard to interpret, and BRTs had high descriptive power but showed signs of overfitting. MAXENT and especially GAMs provided a valuable complexity trade-off, accurate predictions and were ecologically intelligible. Models showed that humpback whales favoured cool (22–23°C) and shallow waters (0–100 m deep) in coastal as well as offshore areas. Citizen science models converged with research survey models, specifically when accounting for spatial sampling bias. Main conclusions: Marine megafauna distribution models present specific challenges that may be addressed through integrative evaluation, independent testing and appropriately tuned statistical algorithms. Specifically, controlling overfitting is a priority when predicting cetacean distributions for large-scale conservation perspectives. Citizen science data appear to be a powerful tool to describe cetacean habitat
On estimation in a spatial functional linear regression model with derivatives
No full textInternational audienceThis paper deals with functional linear regression for spatial data. We study the asymptotic properties of an estimator of a linear model where a spatial scalar response variable is related to a spatial functional explanatory variable and to its derivative. Convergence results with rate of this estimator are derived
Devenir professionnel des internes de médecine générale de la subdivision Océan Indien issus des promotions 2004 à 2012
No full textWhat happened to the interns in general medicine in the Indian Ocean who graduated from the 2004 to 2012 class? In an overall context of declining numbers of general practitioners and a critical medical density in certain territories, we studied the future of general practice residents. The main objective was to find out the proportion of former interns who had been working as freelancers.We conducted a cross-sectional descriptive observational study by electronic questionnaire on their personal and professional situation in 2017.We collected 223 responses, for a participation rate of 86.8%. Former interns were on average 32.6 years of age and 57.8% were women. 36% were employed, 30% were liberal or in collaboration and 27% were substitutes. 57.9% of those settled were still in the Indian Ocean (IO) in 2017. Most of them worked in group practice. The substitutes still present in Reunion were planning to settle there in 62% of the cases. Of these, 92% were doctors from the IO. Eventually, 37% of former interns would remain in the OI. Their main motivations were the living environment and a valued doctor-patient relationship. The comparison between the 2004 to 2008 promotions and the 2009 to 2012 promotions showed a significantly different distribution of exercise modes (pAs we can see in the national data, there has been a change in the way young generalists who favour salaried employees exercise their profession. This is explained in particular by a change in the wishes of young doctors regarding their professional and personal life. If Reunion does not currently suffer from a medical deficit in general medicine, measures should be developed to ensure that the IO residents, once they graduate, remain there to practice ambulatory medicine.Que sont devenus les internes de médecine générale de l’Océan Indien issus des promotions 2004 à 2012 ? Dans un contexte global de baisse des effectifs des médecins généralistes et d’une densité médicale critique dans certains territoires, nous avons étudié le devenir des internes de médecines générale. L’objectif principal était de connaitre la proportion d’anciens internes installés en libéral.Nous avons réalisé une étude observationnelle descriptive transversale par questionnaire électronique portant sur leur situation personnelle et professionnelle en 2017.Nous avons collecté 223 réponses, soit un taux de participation de 86,8%. Les anciens internes étaient âgés en moyenne de 32,6 ans et 57,8% étaient des femmes. 36% étaient salariés, 30% exerçaient dans leur cabinet ou en collaboration et 27% étaient remplaçants. 57,9% des installés étaient toujours dans l’Océan Indien (OI) en 2017. Ils exerçaient majoritairement en cabinet de groupe. Les remplaçants toujours présents à la Réunion envisageaient de s’y installer dans 62% des cas. Parmi eux, on retrouvait 92% des médecins originaires de l’OI. A terme, il resterait 37% des anciens internes dans l’OI. Leurs motivations principales étaient le cadre de vie et une relation médecin/patient appréciée. La comparaison entre les promotions 2004 à 2008 et les promotions 2009 à 2012 montrait une répartition des modes d’exercice significativement différente (pComme nous le retrouvons dans les données nationales, il existe une évolution du mode d’exercice des jeunes généralistes qui privilégient le salariat. Ceci est expliqué notamment par un changement des souhaits des jeunes médecins concernant leur vie professionnelle mais aussi personnelle. Si la Réunion ne souffre pas pour l’instant d’un déficit médical en médecine générale, il convient de développer des mesures pour que les internes de l’OI, une fois diplômés, y restent pour exercer la médecine ambulatoire
Temperature inter-comparison effort in the framework of Hydrological Cycle in the Mediterranean Experiment – Special Observation Period (HyMeX-SOP1)
No full textInternational audienceAccurate measurements of the vertical profiles of atmospheric temperature are necessary to advance the knowledge of dynamics-thermodynamics-radiative interaction mechanisms triggering convection, and ultimately improve weather forecasting capabilities. Comprehensive inter-comparisons between different remote sensing and in-situ sensors have to be carried for the purpose of obtaining accurate error estimates for these sensors. The presentation reports results obtained in the frame of HyMeX-SOP1
