Impact of anthropogenic disturbances on beetle communities of French Mediterranean coastal dunes

In coastal dunes, influenced by anthropogenic activities such as tourism, it is important to determine the relative influence of environmental factors at different spatial scales to evaluate the sensitivity of local communities to disturbances. We analyzed beetle communities of 14 dunes of the French Mediterranean coast: four in the relatively preserved Camargue area, and ten in the Var department, where tourism is intensive. Beetle communities were studied three times in early spring using sand sampling. Species-environment relationships were evaluated at the regional, landscape and local scale using redundancy analysis (RDA) and variability partitioning. About 28 species were identified, of which 15 were sand-specialist species, which accounted for more than 93% of total abundance. The beetle communities of Camargue were significantly different from those of the Var department owing to the pullulation of a Tenebrionid species (Trachyscelis aphodioides Latr.) in the Var, except for one restored dune where the community was very similar to those of Camargue. Our results showed no longitudinal gradient between the two regions. Local factors (dune height, preservation and disturbance index) significantly explained most of the variation in the dominance of T. aphodioides, while some other local factors were important for other psammophilous species. This study also suggests that dune beetle communities are strongly affected on beaches intensively managed for tourism, but beetles are still abundant in much disturbed sites

OPA1 disease alleles causing dominant optic atrophy have defects in cardiolipin-stimulated GTP hydrolysis and membrane tubulation

The dynamin-related GTPase OPA1 is mutated in autosomal dominant optic atrophy (DOA) (Kjer type), an inherited neuropathy of the retinal ganglion cells. OPA1 is essential for the fusion of the inner mitochondrial membranes, but its mechanism of action remains poorly understood. Here we show that OPA1 has a low basal rate of GTP hydrolysis that is dramatically enhanced by association with liposomes containing negative phospholipids such as cardiolipin. Lipid association triggers assembly of OPA1 into higher order oligomers. In addition, we find that OPA1 can promote the protrusion of lipid tubules from the surface of cardiolipin-containing liposomes. In such lipid protrusions, OPA1 assemblies are observed on the outside of the lipid tubule surface, a protein-membrane topology similar to that of classical dynamins. The membrane tubulation activity of OPA1 is suppressed by GTPγS. OPA1 disease alleles associated with DOA display selective defects in several activities, including cardiolipin association, GTP hydrolysis and membrane tubulation. These findings indicate that interaction of OPA1 with membranes can stimulate higher order assembly, enhance GTP hydrolysis and lead to membrane deformation into tubules

Hands Across The Table

Photo of woman looking up on purple and white striped backgroundhttps://scholarsjunction.msstate.edu/cht-sheet-music/2937/thumbnail.jp

Conception, modélisation et commande d’une surface de manipulation sans contact à flux d’air induit

This thesis presents the design, the modeling and the control of a pneumatic manipulatorbased on an original aerodynamic traction principle. An horizontal air flow is induced by strongvertical air jets in order to manipulate objects without contact. The objects are maintained inconstant levitation on an air cushion. Three degrees of freedom positioning of the objects canbe realized thanks to the right combination of distributed air jets. The design of an originalmanipulator using this aerodynamic principle is detailed. The device has been integrated in anexperimental setup in order to validate the manipulation principle : objects can reach velocityof 180 mm/s. Several models of the system have been established. A first model, based on experimentaldata, gives the evolution of the 1 DOF-position of an object on the device. Twoother models, based on a fundamental aerodynamic study, respectively give the evolution of the2- and 3-DOF position of the objet. The three models have been validated experimentally. Inorder to control the position of the object, different controllers have been designed : a PID oneand a robust H1 one. The control of one and two degrees of freedom of the device gives goodperformances : settling time of around 2 s and overshoot less than 5% in most of the cases. Wehave also studied a micro-manipulator that is able to position millimetric sized objects, in twodirections, thanks to inclined air jets. Objects can reach velocity of 123 mm/s, and the resolutionof the positioning is less than 0.4 μm.Ce mémoire décrit la conception, la modélisation et la commande d’un manipulateur pneumatique,fondé sur un principe de traction aérodynamique original. De puissants jets d’air verticauxpermettent de créer un flux d’air horizontal pour manipuler des objets sans contact. Les objetssont maintenus en constante lévitation sur la surface grâce à un coussin d’air, et peuvent positionnés selon trois degrés de libert´ du plan, grâce à la combinaison adéquate et distribuéede jets d’air verticaux. Nous détaillons la conception d’un prototype original de manipulateurexploitant ce principe fluidique. Ce prototype a été intégré dans une plate-forme expérimentaleafin de valider le principe de manipulation : le système permet de déplacer des objets à unevitesse atteignant 180 mm/s. Nous avons modélisé le fonctionnement de la surface selon plusieursméthodes. Un premier modèle comportemental, fond´e sur des données expérimentales, aété établi. Il permet de simuler l’´evolution de la position d’un objet sur la surface, selon un degréde liberté . Deux modèles de connaissance, fond´es sur une étude aérodynamique fondamentale,donnent l’´evolution de la position de l’objet selon respectivement deux et trois degrés de libertédu plan. Chacun des modèles a été validé expérimentalement. Nous avons synthétisé différentscontrˆoleurs afin d’asservir la position de l’objet : un premier, de type PID, et un second, de typerobuste (méthode H1). La commande de un, puis deux degrés de liberté du système, a permisd’atteindre de bonnes performances : temps de réponse d’environ 2 s et dépassement souventinférieur à 5%. Nous avons également étudié un micro-manipulateur pneumatique permettant ded´eplacer des objets de taille millimétrique selon deux directions, grâce à des jets d’air inclinés.Ces objets peuvent atteindre des vitesses de 123 mm/s. La résolution du positionnement estinférieure à 0.4 μm

2-DOF Contactless Distributed Manipulation Using Superposition of Induced Air Flows.

International audienceMany industries require contactless transport and positioning of delicate or clean objects such as silicon wafers, glass sheets, solar cell or flat foodstuffs. The authors have presented a new form of contactless distributed manipulation using induced air flow. Previous works concerned the evaluation of the maximal velocity of transported objects and one degreeof- freedom position control of objects. This paper introduces an analytic model of the velocity field of the induced air flow according to the spatial configuration of vertical air jets. Then two degrees-of-freedom position control is investigated by exploiting the linearity property of the model. Finally the model is validated under closed-loop control and the performances of the position control are evaluated

A new contactless conveyor system for handling clean and delicate products using induced air flows.

International audienceIn this paper, a new contactless conveyor system based on an original aerodynamic traction principle is described and experimented. This device is able to convey without any contact flat objects like silicon wafer, glass sheets or foodstufff thanks to an air cushion and induced air flows. A model of the system is established and the identification of the parameters is carried out. A closed-loop control is proposed for one dimension position control and position tracking. The PID-controller gives good performances for different reference signals. Its robustness to object change and perturbation rejection are also tested

A new Aerodynamic traction principle for handling products on an Air Cushion.

International audienceThis paper introduces a new aerodynamic traction principle for handling delicate and clean products, such as silicon wafers, glass sheets or flat foodstuff. The product is carried on a thin air cushion and transported along the system by induced air flows. This induced air flow is the indirect effect of strong vertical air-jets that pull the surrounding fluid. The paper provides a qualitative explanation of the operating principles and a description of the experimental device. Very first experimental results with active control are presented. The maximum velocity and acceleration that can be obtained for the considered device geometry meet the requirements for industrial applications

Gene structure and chromosomal localization of mouse Opa1 : its exclusion from the Bst locus

BACKGROUND: Autosomal dominant optic atrophy type 1 (DOA) is the most common form of hereditary optic atrophy in human. We have previously identified the OPA1 gene and shown that it was mutated in patients with DOA. OPA1 is a novel member of the dynamin GTPase family that play a role in the distribution of the mitochondrial network. The Bst (belly spot and tail) mutant mice show atrophy of the optic nerves and previous mapping data raise the possibility that Bst and OPA1 are orthologs. In order to analyse the Bst mouse as a model for DOA, we therefore characterized mouse Opa1 and evaluated it as a candidate for the Bst mutant mouse. RESULTS: Comparison of mouse and human OPA1 sequences revealed 88% and 97% identity at the nucleotide and amino acid levels, respectively. Presence of alternatively spliced mRNAs as seen in human was conserved in the mouse. Screening of the whole mRNA coding sequence and of the 31 exons of Opa1 did not reveal any mutation in Bst. Using a radiation hybrid panel (T31), we mapped Opa1 to chromosome 16 between genetic markers D16Mit3 and D16Mit124, which is 10 cM centromeric to the Bst locus. CONCLUSION: On the basis of these results we conclude that Opa1 and Bst are distinct genes and that the Bst mouse is not the mouse model for DOA

Robust control of a planar manipulator for flexible and contactless handling

International audienceMany industries require non-contact and flexible manipulation systems, such as magnetic or pneumatic devices. In this paper, we describe a one-degree-of-freedom position control of an induced-air-flow surface. This device allows to convey objects on an air cushion using an original aerodynamic traction principle. A model of the system is established and the parameters are identified experimentally. A H1 robust controller is designed and implemented on the device in order to control the object position. Experiments with objects of various dimensions and materials are conducted and showed the robustness capabilities of the controller

3-DOF potential air flow manipulation by inverse modeling control.

International audiencePotential air flows can be used to perform nonprehensile contactless manipulations of objects gliding on airhockey table. In this paper, we introduce a general method able to perform 3-DOF position control of an object with potential air flow manipulators. This approach is based on an inverse modeling control scheme to perform closed-loop position servoing. We propose to use a linear programming algorithm to determine which sinks have to be activated in order to produce the suitable potential air flow to obtain the desired object motion. This approach is then validated on an experimental manipulator