Launcher attitude control: discrete-time robust design and gain-scheduling

In this paper, a robust multi-objective design for the control of a launcher during atmospheric flight is investigated. This approach is based on the Cross Standard Form formulation which allows to incorporate the various specifications of the launcher problem in a streamlined manner. An important feature of this approach is that a non-conventional LQG/LTR approach, required to satisfy time-domain specifications, can be embedded into a more general standard problem in order to account for frequency-domain robustness constraints. The specific form of this standard problem is also very interesting for gain scheduling

Importance of the Two Dissimilatory (Nar) Nitrate Reductases in the Growth and Nitrate Reduction of the Methylotrophic Marine Bacterium Methylophaga nitratireducenticrescens JAM1

Methylophaga nitratireducenticrescens JAM1 is the only reported Methylophaga species capable of growing under anaerobic conditions with nitrate as electron acceptor. Its genome encodes a truncated denitrification pathway, which includes two nitrate reductases, Nar1 and Nar2; two nitric oxide reductases, Nor1 and Nor2; and one nitrous oxide reductase, Nos; but no nitrite reductase (NirK or NirS). The transcriptome of strain JAM1 cultivated with nitrate and methanol under anaerobic conditions showed the genes for these enzymes were all expressed. We investigated the importance of Nar1 and Nar2 by knocking out narG1, narG2 or both genes. Measurement of the specific growth rate and the specific nitrate reduction rate of the knockout mutants JAM1ΔnarG1 (Nar1) and JAM1ΔnarG2 (Nar2) clearly demonstrated that both Nar systems contributed to the growth of strain JAM1 under anaerobic conditions, but at different levels. The JAM1ΔnarG1 mutant exhibited an important decrease in the nitrate reduction rate that consequently impaired its growth under anaerobic conditions. In JAM1ΔnarG2, the mutation induced a 20-h lag period before nitrate reduction occurred at specific rate similar to that of strain JAM1. The disruption of narG1 did not affect the expression of narG2. However, the expression of the Nar1 system was highly downregulated in the presence of oxygen with the JAM1ΔnarG2 mutant. These results indicated Nar1 is the major nitrate reductase in strain JAM1 but Nar2 appears to regulate the expression of Nar1

Exact Boundary Controllability of a System of Mixed Order with Essential Spectrum

International audienceWe address in this work the exact boundary controllability of a linear hyperbolic system of the form $u^{\prime\prime}+Au=0$ with $u=\left(u_{1},u_{2}\right)^{T}$ posed in $(0,T)\times(0,1)^{2}$. A denotes a self-adjoint operator of mixed order that usually appears in the modelization of a linear elastic membrane shell. The operator A possesses an essential spectrum which prevents the exact controllability from holding uniformly with respect to the initial data $\left(u^{0},u^{1}\right)$. We show that the exact controllability holds by one Dirichlet control acting on the first variable $u_{1}$ for any initial data $\left(u^{0},u^{1}\right)$ generated by the eigenfunctions corresponding to the discrete part of the spectrum of A. The proof relies on a suitable observability inequality obtained by way of a full spectral analysis and the adaptation of an Ingham-type inequality for the Laplacian in two spatial dimensions. This work provides a nontrivial example of a system controlled by a number of controls strictly lower than the number of components. Some numerical experiments illustrate our study

Impact des variations du climat et du niveau marin sur les canyons sous-marins du Golfe du Lion (France) et de la marge de l'Ebre (Catalogne) au cours du Plio-Quaternaire

Climate and sea-level changes with various magnitudes control continental erosion, sediment transport and its delivery to the deep basin. Submarine canyons, that are erosional features at a first glance, are conduits for sediment transport from the continental shelf to the deep sea. Little studies focused on the relationship between canyon infill, sediment delivery and sea-level variations. The chronology of canyon development and evolution through geological time remains speculative. This thesis is dedicated to the understanding of the genesis of submarine canyons in the western Mediterranean Sea during the Plio-Quaternary. This period occurred after the major erosion of Mediterranean continental margins during the Messinian Salinity Crisis. Canyons were initiated by retrogressive erosion during the Pliocene. They further developed in relation with the amplification of sea-level changes during the Quaternary (up to 150 m). The results are based on a large range of 2D and 3D seismic data resolution and chrono-stratigraphic constraints. The stratigraphic signature of Milankovitch (mainly 100 and 40 ka) is revealed within canyon heads. Rapid climate and sea-level changes (Bond Cycles) have also a distinct signature by controlling the type and amount of sediment delivered in canyon heads, and the connection/disconnection with fluvial systems.Les fluctuations du climat et du niveau marin, de plus ou moins grande amplitude, influencent le taux d’érosion sur le continent, le transport de sédiment vers l’océan et sa distribution vers le bassin profond. Les canyons sous-marins, structures érosives de premier abord, sont les zones de transfert privilégiées entre le plateau continental et le bassin profond. Peu d’études se sont concentrées sur la relation entre le remplissage des canyons, l’acheminement des sédiments et les variations du niveau marin. La chronologie de leur mise en place et de leur évolution aux échelles de temps géologiques restent également largement spéculatifs. Ce travail est consacré à la genèse des canyons sous-marins au Plio-Quaternaire sur les marges de l’Ebre et du Golfe du Lion, en Méditerranée occidentale. Cette genèse intervient après la crise de salinité messinienne, qui a conduit au démantèlement par érosion continentale des marges méditerranéennes. Après une initiation par érosion régressive au Pliocène, les canyons sous-marins connaissent un développement majeur lors de la mise en place des cycles climatiques de 100 ka au Quaternaire, en lien avec l’amplification des oscillations du niveau marin pouvant atteindre 150 m. L’utilisation et la comparaison de données sismiques (2D et 3D) de résolution et pénétration différentes, couplées à des calages chrono-stratigraphiques par forages, permettent de mettre en évidence le lien important entre les cycles climatiques de Milankovitch (principalement 100 et 41 ka) et l’architecture des têtes de canyons. Les changements rapides du climat et du niveau marin (cycles de Bond) ont également une influence importante sur le flux sédimentaire et les processus de transport, ainsi que sur la connexion/déconnexion avec les systèmes fluviatiles

Percutaneous reduction and fixation of an intra-articular calcaneal fracture using an inflatable bone tamp: description of a novel and safe technique

Calcaneal fractures are common injuries involving the hind foot and often a source of significant long-term morbidity. Treatment options have changed throughout the ages from periods of preferred nonoperative management to closed reduction with a mallet, and more recently, open reduction and anatomic internal fixation. The current treatment of choice; however, is often debated, as open management of these fractures carries many risks to include wound breakdown and infection. A less invasive form of surgical management through small incisions, while maintaining the ability to obtain joint congruency, anatomic alignment, and restore calcaneal height and width would be ideal. We propose a novel form of fracture reduction using an inflatable bone tamp and percutaneous fracture fixation. Preoperative planning and experienced fluoroscopy is crucial to successful management using this method. Although we achieved successful radiographic outcome in this case, long-term functional outcome of this technique are yet to be published

Contrôlabilité de systèmes gouvernés par des équations aux dérivées partielles

Contrôlabilité de systèmes gouvernés par des équations aux dérivées partiellesControllability of systems governed by partial differential equationsBESANCON-Bib. Electronique (250560099) / SudocSudocFranceF

Artificial floristic diversity of private gardens in the natural regional park of Luberon: the case of Lauris village

L’urbanisation croissante des communes rurales dans les trente dernières années a conduit à un essor des zones résidentielles autour des noyaux villageois. Les jardins privatifs de ces zones constituent des lieux d’introduction d’espèces horticoles exotiques et locales qui contribuent fortement à la richesse floristique des zones urbanisées. Nous nous sommes attachés à décrire cette flore au niveau des jardins de la commune de Lauris (Vaucluse, France) selon un gradient d’urbanisation. Nos résultats montrent la forte richesse floristique de ces espaces puisque 573 taxa horticoles ont été inventoriés sur 21,5 ha de surface de jardin. La plupart des taxa introduits sont originaires d’Asie, d’Amérique et d’Europe. Les taxa du Bassin méditerranéen sont représentés à la hauteur de 12% et les plus fréquents sont Nerium oleander, Olea europea, Cupressus sempervirens, Lavandula angustifolia, Rosmarinus officinalis et Viburnum tinus. Vingt et un taxa introduits dans les jardins sont actuellement signalés comme invasifs avérés ou potentiels en région méditerranéenne, augmentant le risque d’invasions biologiques. Des variations de la composition floristique sont également observées le long du gradient d’urbanisation et s’expriment par des patrons floristiques différents selon le type d’urbanisation. Les jardins de la zone de forte densité de bâti présentent en effet une strate chaméphytique développée (28%), une forte proportion de thérophytes (11%) et un grand nombre d’espèces sud-africaines. Les zones de moyenne et de faible densité de bâti regroupent des jardins avec une strate arborée haute comprise entre 2 et 30 m. On observe ainsi une fermeture du milieu en zone agricole et une substitution de Pinus halepensis par des espèces arborées horticoles en zone forestière. Les facteurs structuraux du jardin, les pratiques horticoles et les éléments paysagers apparaissent déterminants dans l’explication de ces variations et méritent donc un intérêt tout particulier pour la compréhension des mécanismes de répartition des patrons floristiques existants.Increasing urbanisation during the last thirty three years in rural area lead to rapid developpement of residential zones around village units. The introduction of a new set of horticultural species in private gardens contributes to urban floristic richness. We described this flora in private gardens of Lauris village (Vaucluse, South-eastern France). Our results showed the great floristic richness of these spaces with 573 horticultural taxa collected on 21,5 ha. Flora is mainly made up of asiatic, american and european taxa. Twelve per cent are mediterranean basin taxa, the most frequent being Nerium oleander, Olea europea, Cupressus sempervirens, Lavandula angustifolia, Rosmarinus officinalis and Viburnum tinus.Twenty one introduced taxa in gardens are signalled like invasive in the Mediterranean region, increasing biological invasion risks. Some variations in floristic composition were observed along the rural –urban gradient and different floristic patterns were according to habitations density. Urban gardens presented a developped chamephyte stratum and a great proportion of therophytes and South Africa’s species. Gardens with a high wooded stratum (2<H<30 m) were found in both urban sprawl and periurban areas. The opened agricultural area is being invaded by trees and horticultural tree species replace Pinus halepensis in periurban forests. Garden structure, gardening pratices and landscape components seem to be important to explain these variations and must be taken into account to understand distribution mecanisms these floristic patterns

Adherence to a femoral neck fracture treatment guideline

Purpose: In 2007 the Dutch Surgical Society published a clinical practice guideline for the treatment of hip fracture patients, based on the best available international evidence at that time. We investigated to what extent treatment of femoral neck fracture patients in the Netherlands corresponded with these guidelines, and determined differences in patient characteristics between the treatment groups. Methods: All femoral neck fracture patients treated in 14 hospitals between February 2008 and August 2009 were included. Patient characteristics, X-rays, and treatment data were collected retrospectively. Results: From a total of 1,250 patients 59 % had been treated with arthroplasty, 39 % with internal fixation, and 2 % with a non-operative treatment. While 74 % of the treatment choices complied with the guideline, 12 % did not. In 14 % adherence could not be determined from the available data. Arthroplasty was preferred over internal fixation in elderly patients with severe comorbidity, pre-fracture osteoporosis and a displaced fracture, who were ambulatory with aids pre-fracture (odds ratio, OR 2.2-58.1). Sliding hip screws were preferred over cancellous screws in displaced fractures (OR 1.9). Conclusions: Overall guideline adherence was good. Most deviations concerned treatment of elderly patients with a displaced fracture and implant use in internal fixation. Additional data on these issues, preferably at a higher scientific level of evidence, is needed in order to improve the guideline and to reinforce a more uniform treatment of these patients