Optimal control of vortex core polarity by resonant microwave pulses

In a vortex-state magnetic nano-disk, the static magnetization is curling in the plane, except in the core region where it is pointing out-of-plane, either up or down leading to two possible stable states of opposite core polarity p. Dynamical reversal of p by large amplitude motion of the vortex core has recently been demonstrated experimentally,raising fundamental interest for potential application in magnetic storage devices. Here we demonstrate coherent control of p by single and double microwave pulse sequences, taking advantage of the resonant vortex dynamics in a perpendicular bias magnetic field. Optimization of the microwave pulse duration required to switch p allows to experimentally infer the characteristic decay time of the vortex core in the large oscillation regime. It is found to be more than twice shorter than in the small oscillation regime, raising the fundamental question of the non-linear behaviour of magnetic dissipation

Gene activated matrices for bone and cartilage regeneration in arthritis

The GAMBA Consortium is developing a novel gene-activated matrix platform for bone and cartilage repair with a focus on osteoarthritis-related tissue damage. The scientific and technological objectives of this project are complemented with an innovative program of public outreach, actively linking patients and society to the evolvement of this project. The GAMBA platform will implement a concept of spatiotemporal control of regenerative bioactivity on command and demand. A gene activated matrix is a biomaterial with embedded gene vectors that will genetically modify cells embedded in or colonising the matrix. The platform comprises modules that self-adapt to the biological environment and that can be independently addressed with endogenous biological and exogenous physical or pharmacological stimuli, resulting in a temporally and spatially coordinated growth factor gene expression pattern. This reproduces, within the matrix, key elements of natural tissue formation. The modules are a biomimetic hyaluronan gel, a ceramic matrix, growth factor-encoding gene vector nanoparticles, magnetic nanoparticles and mesenchymal stem cells. Anatomical adaptivity is achieved with engineered thermal properties of the polymer matrix, which embeds other modules, selected according to functional requirements. Mechanical support is provided by Micro Macroporous Biphasic Calcium Phosphate (MBCP ™ ), a resorbable material approved for clinical use. Spatiotemporal control of bioactivity and responsiveness to physiological conditions is represented, firstly, in the spatial distribution and release profiles of gene vectors within the composite matrix and, secondly, by letting local and external biological or physical stimuli activate the promoters driving the expression of vector-encoded growth factor transgenes. This concept is implemented by a multidisciplinary team from leading European institutions. Here, we report on the concepts, objectives and some preliminary results of the GAMBA project which is funded in 7th Framework Programme of the European Union THEME [NMP-2009-2.3-1], Biomimetic gels and polymers for tissue repair

OveRSoC: A Framework for the Exploration of RTOS for RSoC Platforms

This paper presents the OveRSoC project. The objective is to develop an exploration and validation methodology of embedded Real Time Operating Systems (RTOSs) for Reconfigurable System-on-Chip-based platforms. Here, we describe the overall methodology and the corresponding design environment. The method is based on abstract and modular SystemC models that allow to explore, simulate, and validate the distribution of OS services on this kind of platform. The experimental results show that our components accurately model the dynamic and deterministic behavior of both application and RTOS

Réseaux de vortex dans Bi2_2Sr2_2Ca1_1Cu2_2Ox_x

Results of the defect influence on the flux line lattice in Bi$_2$Sr$_2$Ca$_1$Cu$_2$O$_x$ single crystals are presented. These crystals, non irradiated or irradiated at GANIL with heavy ions (Pb$^{56+}$, 6 GeV) have been decorated with Ni particles in the superconducting state using the Bitter technique. The defects involved are columnar defects. Resulting decorated flux line patterns have been characterized using scanning electron microscopy and computer image analysis. Disorder of the decorated flux line networks has been found to be strongly dependent on the defect density, which results from the irradiation. In order to characterize this disorder, a method for determining elastic energy terms in the deformation of flux line patterns has been investigated. This method can be applied if Fourier transforms of the decorated flux line patterns exhibit distinct reflections.Nous présentons une étude sur l'influence des défauts vis-à-vis du piégeage des lignes de flux magnétique dans des monocristaux de Bi$_2$Sr$_2$Ca$_1$Cu$_2$O$_x$. Ces monocristaux, non irradiés ou irradiés sur l'accélérateur du GANIL avec des ions (Pb$^{56+}$) d'énergie 6 GeV ont été décorés dans l'état supraconducteur selon la technique de Bitter. Les réseaux de lignes de flux magnétique ont eté caractérisés par microscopie électronique à balayage et avec un analyseur d'images. Les résultats montrent que les réseaux de lignes de flux magnétique sont fortement dépendant de la densité de défauts résultant de l'irradiation. Pour caractériser l'état de désordre, nous avons appliqué une méthode de calcul de termes d'énergie élastique des réseaux de lignes de flux magnétique. Cette méthode ne peut être appliquée que si la transformée de Fourier des réseaux de vortex présente des réflexions discrètes

Quatre ans de recherche urbaine 2001-2004. Volume 2

Destinée à promouvoir une recherche fondamentale pluridisciplinaire, l’Action Concertée Incitative Ville (ACIV) créée par le Ministère de la Recherche visait au renouvellement des problématiques, afin de mieux comprendre les enjeux urbains contemporains, les transformations en cours et d’anticiper les évolutions. Cet ouvrage dresse l’inventaire des recherches soutenues lors des quatre années de programmation de l’ACIV. Les deux tomes rassemblent 143 contributions qui manifestent, de la part d’équipes « confirmées », de « jeunes » chercheurs ou de doctorants, le foisonnement et la richesse des thèmes, des problématiques, des méthodes et des terrains. Ces contributions qui rendent compte des recherches financées par l’ACIV et des allocations de thèse soutenues par elle, s’organisent autour de six thématiques : « Formes urbaines, cultures et modes de vie », « Cohésion sociale et citoyenneté », « Modifications d’échelles, recomposition des systèmes territoriaux et gouvernance », « Cultures urbanistiques : des sources de l’histoire urbaine au développement urbain durable », « Milieux physiques, ambiances urbaines et technologies », « Management, gestion et systèmes techniques ». La postface ouvre, quant à elle, une réflexion critique et prospective « à plusieurs voix » sur le devenir de la recherche urbaine