Christianisme

Le christianisme est une religion abrahamique, originaire du Proche-Orient, fondée sur l'enseignement, la personne et la vie de Jésus de Nazareth, tels qu'interprétés à partir du Nouveau Testament. Il s'agit d'une religion du salut considérant Jésus-Christ comme le Messie annoncé par les prophètes de l'Ancien Testament. La foi en la résurrection de Jésus est au cœur du christianisme car elle signifie le début d'un espoir d'éternité libéré du mal. Les premières communautés chrétiennes naissent au en Terre sainte et dans les grandes villes de la diaspora juive telles que Rome, Éphèse, Antioche et Alexandrie. Le christianisme se développe à partir du dans l'Empire romain, dont il devient la religion officielle à la fin du , mais aussi en Perse, en Inde et en Éthiopie. Au Moyen Âge, le christianisme devient majoritaire en Europe, tandis qu'il s'amenuise face à l'islam au Proche-Orient. Il est devenu la religion la plus importante de la planète en raison de son expansion en Amérique à p

Towards a theoretical foundation for morphological computation with compliant bodies

Auke Ijspeert, Rolf Pfeifer

The control of compliant robots is, due to their often nonlinear and complex dynamics, inherently difficult. The vision of morphological computation proposes to view these aspects not only as problems, but rather also as parts of the solution. Non-rigid body parts are not seen anymore as imperfect realizations of rigid body parts, but rather as potential computational resources. The applicability of this vision has already been demonstrated for a variety of complex robot control problems. Nevertheless, a theoretical basis for understanding the capabilities and limitations of morphological computation has been missing so far. We present a model for morphological computation with compliant bodies, where a precise mathematical characterization of the potential computational contribution of a complex physical body is feasible. The theory suggests that complexity and nonlinearity, typically unwanted properties of robots, are desired features in order to provide computational power. We demonstrate that simple generic models of physical bodies, based on mass-spring systems, can be used to implement complex nonlinear operators. By adding a simple readout (which is static and linear) to the morphology, such devices are able to emulate complex mappings of input to output streams in continuous time. Hence, by outsourcing parts of the computation to the physical body, the difficult problem of learning to control a complex body, could be reduced to a simple and perspicuous learning task, which can not get stuck in local minima of an error function.

2011

Electrovariable gold nanoparticle films at liquid–liquid interfaces: from redox electrocatalysis to Marangoni-shutters

Hubert Girault, Grégoire Clément Gschwend, Pekka Eero Peljo, Evgeny Smirnov

Control over the physical properties of nanoparticle assemblies at a liquid–liquid interface is a key technological advancement to realize the dream of smart electrovariable nanosystems. Electrified interfaces, such as the interface between two immiscible electrolytes solutions (ITIES), are almost an ideal platform for realizing this dream. Here, we show that the Galvani potential difference across soft interfaces can be effectively used to manipulate: (i) the reactivity of gold nanoparticle assemblies through varying the Fermi level (both chemically and electrochemically); (ii) the location distribution of the nanoparticles at the liquid–liquid interface. In the first case, in addition to our previous studies on electron transfer reactions (ET) across the ITIES, we used intensity modulated photocurrent spectroscopy (IMPS) to study the kinetics of photo-induced electrochemical reactions at the ITIES. As expected, the direct adsorption of gold nanoparticles at the interface modifies the kinetics of the ET reaction (socalled, interfacial redox electrocatalysis), however it did not lead to an increased photocurrent by “plasmonic enhancement”. Rather, we found that the product separation depends on double layer effects while the product recombination is controlled by the Galvani potential difference between the two phases. In the second case, we demonstrated that polarizing the ITIES caused migration of gold nanoparticles from the middle region of the cell to its periphery. We called such systems “Marangoni-type shutters”. This type of electrovariable plasmonic system did not experience diffusion limitation in terms of the adsorption/ desorption of nanoparticles and the entire movement of nanoparticle assemblies happened almost instantly (within a second). It opens a fresh view on electrovariable plasmonics and presents new opportunities to create smart nanosystems at the ITIES driven with an electric field.

Royal Society of Chemistry2017

Electrovariable gold nanoparticle films at liquid–liquid interfaces: from redox electrocatalysis to Marangoni-shutters

Hubert Girault, Grégoire Clément Gschwend, Pekka Eero Peljo, Evgeny Smirnov

Royal Society of Chemistry2017

Towards a theoretical foundation for morphological computation with compliant bodies

Electrovariable gold nanoparticle films at liquid–liquid interfaces: from redox electrocatalysis to Marangoni-shutters

Cyclic Voltammetry for the Transfer of Multiply Charged Ions at Large ITIES: General Computational Methodology and Application to Simple and Facilitated Ion Transfer Reactions

Towards a theoretical foundation for morphological computation with compliant bodies

Electrovariable gold nanoparticle films at liquid–liquid interfaces: from redox electrocatalysis to Marangoni-shutters

Cyclic Voltammetry for the Transfer of Multiply Charged Ions at Large ITIES: General Computational Methodology and Application to Simple and Facilitated Ion Transfer Reactions