A Natural Seismic Isolating System: The Buried Mangrove Effects

The Belleplaine test site, located in the island of Guadeloupe (French Lesser Antilles) includes a three-accelerometer vertical array, designed for liquefac- tion studies. The seismic response of the soil column at the test site is computed using three methods: the spectral ratio method using the vertical array data, a numerical method using the geotechnical properties of the soil column, and an operative fre- quency domain decomposition (FDD) modal analysis method. The Belleplaine test site is characterized by a mangrove layer overlaid by a stiff sandy deposit. This con- figuration is widely found at the border coast of the Caribbean region, which is exposed to high seismic hazard. We show that the buried mangrove layer plays the role of an isolation system equivalent to those usually employed in earthquake engineering aimed at reducing the seismic shear forces by reducing the internal stress within the structure. In our case, the flexibility of the mangrove layer reduces the distortion and the stress in the sandy upper layer, and consequently reduces the potential of liquefaction of the site

Kinetic self-organization of trenched templates for the fabrication of versatile ferromagnetic nanowires

We have self-organized versatile magnetic nanowires, ie with variable period and adjustable magnetic anisotropy energy (MAE). First, using the kinetic roughening of W(110) uniaxial templates of trenches were grown on commercial Sapphire wafers. Unlike most templates used for self-organization, those have a variable period, 4-12nm are demonstrated here. Fe deposition then results in the formation of wires in the trenches. The magnitude of MAE could be engineered up or down by changing the capping- or underlayer, in turn affecting the mean superparamagnetic temperature, raised to 175K so far.Comment: 3 page

Mechanical properties of the elemental nanocomponents of nacre structure

Sheet nacre is a nanocomposite with a multiscale structure displaying a lamellar “bricks and mortar” microarchitecture. In this latter, the brick refer to aragonite platelets and the mortar to a soft organic biopolymer. However, it appears that each brick is also a nanocomposite constituted as CaCO3 nanoparticles reinforced organic composite material. What is the role of this “intracrystalline” organic phase in the deformation of platelet? How does this nanostructure control the mechanical behaviour of sheet nacre at the macroscale? To answer these questions, the mechanical properties of each nanocomponents are successively investigated and computed using spherical and sharp nanoindentation tests combined with a structural model of the organomineral platelets built from AFM investigations

The impact of oil price variations : a DSGE Model for the Canadian Economy

Nous analysons les impacts de chocs reliés au prix du pétrole en utilisant un modèle dynamique stochastique d' équilibre général pour l'économie canadienne (DSGE). Les mouvements dans le prix du pétrole, modélisé comme une variable exogène, affectent l'économie à travers une variation de l'utilisation du capital. Les simulations du modèle suite à des chocs reliés au pétrole sont utilisée pour analyser leurs impacts sur les variables macroéconomiques. Un choc positif sur le prix mondial du pétrole augmente immédiatement la valeur du dollar canadien. Le choc crée également un effet de richesse pour les ménages canadiens et haussent leurs salaires. Bien que le choc diminue les exportations, l'effet de richesse augmente la consommation et la production de biens intermédiaires. Étant donné l'effet sur le taux de change, le choc augmente également les importations de biens

Dependence of DNA persistence length on ionic strength of solutions with monovalent and divalent salts: a joint theory-experiment study

Using high-throughput Tethered Particle Motion single molecule experiments, the double-stranded DNA persistence length, $L_p$, is measured in solutions with Na$^+$ and Mg$^{2+}$ ions of various ionic strengths, $I$. Several theoretical equations for $L_p(I)$ are fitted to the experimental data, but no decisive theory is found which fits all the $L_p$ values for the two ion valencies. Properly extracted from the particle trajectory using simulations, $L_p$ varies from 30~nm to 55~nm, and is compared to previous experimental results. For the Na$^+$ only case, $L_p$ is an increasing concave function of $I^{-1}$, well fitted by Manning's electrostatic stretching approach, but not by classical Odjik-Skolnick-Fixman theories with or without counter-ion condensation. With added Mg$^{2+}$ ions, $L_p$ shows a marked decrease at low $I$, interpreted as an ion-ion correlation effect, with an almost linear law in $I^{-1}$, fitted by a proposed variational approach

Metric Tensor for Multicomponent Edge Detection

International audienceIn this paper, we present the use of differential geometry for the segmentation of multispectral images, which allows us to unify several known methods including projecting onto a particular axis or a particular plan. This is done by choosing a metric tensor on the feature space computing the pullback of the metric tensor and applying standard Di Zenzo algorithm

Spectral-phase interferometry for direct electric-field reconstruction applied to seeded extreme-ultraviolet free-electron lasers

We present a setup for complete characterization of femtosecond pulses generated by seeded free-electron lasers (FEL's) in the extreme-ultraviolet spectral region. Two delayed and spectrally shifted replicas are produced and used for spectral phase interferometry for direct electric field reconstruction (SPIDER). We show that it can be achieved by a simple arrangement of the seed laser. Temporal shape and phase obtained in FEL simulations are well retrieved by the SPIDER reconstruction, allowing to foresee the implementation of this diagnostic on existing and future sources. This will be a significant step towards an experimental investigation and control of FEL spectral phase

Живучесть интеллектуальных систем управления, созданных на базе рецепторно-эффекторных нейроподобных растущих сетей

В статье рассмотрены вопросы надежности распознавания образов и живучести систем искусственного интеллекта, разработанных на базе рецепторно-эффекторных нейроподобных растущих сетей. Нейроподобные растущие структуры работают с высокой надежностью и обеспечивают живучесть интеллектуальных систем. Эксперименты, проведенные на моделях интеллектуальных систем, показывают, что выход из строя большого количества элементов нейроподобной сети не приводит к отказам в работе всей системы.У статті розглянуті питання надійності розпізнавання образів і живучості систем штучного інтелекту, розроблених на базі рецепторно-ефекторних нейроподібних зростаючих мереж. Нейроподібні зростаючі структури працюють з високою надійністю і забезпечують живучість інтелектуальних систем. Експерименти, проведені на моделях інтелектуальних систем, показують, що вихід з ладу великої кількості елементів нейроподібної мережі не приводить до відмов у роботі всієї системи.The questions of reliability of pattern recognition and artificial intelligence systems survivability developed on the basis of receptor-effector neural growing networks were regarded. Growing neural structures operate with a high reliability and ensure survivability of intelligent systems. Experiments conducted on the models of intelligent systems show that the failure of a large number of neural network elements does not lead to failures in the system