Modeling visual-based pitch, lift and speed control strategies in hoverflies

<div><p>To avoid crashing onto the floor, a free falling fly needs to trigger its wingbeats quickly and control the orientation of its thrust accurately and swiftly to stabilize its pitch and hence its speed. Behavioural data have suggested that the vertical optic flow produced by the fall and crossing the visual field plays a key role in this anti-crash response. Free fall behavior analyses have also suggested that flying insect may not rely on graviception to stabilize their flight. Based on these two assumptions, we have developed a model which accounts for hoverflies´ position and pitch orientation recorded in 3D with a fast stereo camera during experimental free falls. Our dynamic model shows that optic flow-based control combined with closed-loop control of the pitch suffice to stabilize the flight properly. In addition, our model sheds a new light on the visual-based feedback control of fly´s pitch, lift and thrust. Since graviceptive cues are possibly not used by flying insects, the use of a vertical reference to control the pitch is discussed, based on the results obtained on a complete dynamic model of a virtual fly falling in a textured corridor. This model would provide a useful tool for understanding more clearly how insects may or not estimate their absolute attitude.</p></div

A first update on mapping the human genetic architecture of COVID-19

peer reviewe

Rapport II.6. Comparaison des effets du vent et de l'ensoleillement sur les contraintes statiques dans une structure d'aéroréfrigérant à tirage naturel

Comparison of wind and sun heating effects on static stresses in a natural draft cooling tower shell. A thermal modelling of a cooling tower shell under sun heating leads to a loading whose associated stresses are nearly isotropic and get from traction to compression from one side of the shell to the other. The comparison with a schematic loading due to wind and dead weigth shows that thermal stresses are about 1/3 of the stresses resulting from the last loading.Une simulation thermique d'une coque d'aéroréfrigérant sous ensoleillement permet de définir un chargement vraisemblable. Les contraintes associées sont pratiquement isotropes et changent de signe d'une face à l'autre du voile. La comparaison avec un chargement schématique vent plus poids propre montre que les contraintes thermiques sont de l'ordre du tiers des contraintes maximales résultant de ce dernier chargement.Boisserie J. M., Viollet Pierre-Louis. Rapport II.6. Comparaison des effets du vent et de l'ensoleillement sur les contraintes statiques dans une structure d'aéroréfrigérant à tirage naturel. In: Rejets de chaleur à l'atmosphère. Gestion des calories et hydraulique associée. Compte rendu des XVIes journées de l'hydraulique. Paris, 16-18 septembre 1980. Tome 1, 1980

Rapport III. 12 Étude statistique tridimensionnelle des panaches d'aéroréfrigérants. Méthode et résultats relatifs à l’influence de la puissance et des conditions de rejets

Three-dimensional statistical study of cooling tower plumes Method and results on the effects of power and discharge conditions. The three dimensional computer code PANACH which was achieved using laboratory experiments, to calibrate the turbulent mixing parameters, and then validated with on site measurements, is used in order to estimate a three dimensional statistical plume prevision. As the computing time does not allow to calculate each meteorological set of date, a classification of these date was adopted. This method which was developed by the National Meteorology Board is based upon a double classification with basic classes in which all plumes are assumed to be dynamically similar and a sub-classification allowing to take into account the real moisture vertical profiles. This statistical method is applied to the cases of 2 and 4 wet-type natural draft cooling towers of 1300 MWe and of 2 wet-dry and dry.Le code de calcul tridimensionnel PANACH après avoir été mis au point à partir d'essais sur modèle réduit et validé à partir de campagnes de mesures en nature a été utilisé pour estimer une statistique tridimensionnelle de panaches. Les temps de calcul ne permettant pas d'effectuer un calcul pour chaque radiosondage, une méthode de classification a été adoptée. Cette méthode développée par la Météorologie Nationale est basée sur une double classification comprenant des classes de bases dans lesquelles les panaches sont supposés dynamiquement semblables et une sous-classification pour mieux tenir compte des profils réels d'humidité. Cette méthode statistique a ensuite été appliquée au cas de 2 ou 4 tranches de 1300 MWe équipées d'aéroréfrigérants à tirage naturel de types humide, sec et humide-sec.Darles A., Sabaton M., Gland H., Viollet Pierre-Louis. Rapport III. 12 Étude statistique tridimensionnelle des panaches d'aéroréfrigérants. Méthode et résultats relatifs à l’influence de la puissance et des conditions de rejets. In: Rejets de chaleur à l'atmosphère. Gestion des calories et hydraulique associée. Compte-rendu des XVIes journées de l'hydraulique. Paris, 16-18 septembre 1980. Tome 2, 1980

Beyond AICA riboside: In search of new specific AMP-activated protein kinase activators.

5-Aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICA riboside) has been extensively used in vitro and in vivo to activate the AMP-activated protein kinase (AMPK), a metabolic sensor involved in both cellular and whole body energy homeostasis. However, it has been recently highlighted that AICA riboside also exerts AMPK-independent effects, mainly on AMP-regulated enzymes and mitochondrial oxidative phosphorylation (OXPHOS), leading to the conclusion that new compounds with reduced off target effects are needed to specifically activate AMPK. Here, we review recent findings on newly discovered AMPK activators, notably on A-769662, a nonnucleoside compound from the thienopyridone family. We also report that A-769662 is able to activate AMPK and stimulate glucose uptake in both L6 cells and primary myotubes derived from human satellite cells. In addition, A-769662 increases AMPK activity and phosphorylation of its main downstream targets in primary cultured rat hepatocytes but, by contrast with AICA riboside, does neither affect mitochondrial OXPHOS nor change cellular AMP:ATP ratio. We conclude that A-769662 could be one of the new promising chemical agents to activate AMPK with limited AMPK-independent side effects. (c) 2008 IUBMB IUBMB Life, 2008

L'AMPK, une protéine impliquée dans les interactions entre les cellules nourricières et les cellules germinales

National audienc

Alternating hemiplegia of childhood: Retrospective genetic study and genotype-phenotype correlations in 187 subjects from the US AHCF registry

© 2015 Viollet et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credite