Interesting Electrophysiological Findings in a Patient With Coincidental Right Ventricular Outflow Tract and Atrioventricular Nodal Reentrant Tachycardia

Tachycardia induced tachycardias are not common in clinical practice, and it is believed that most cases of double tachycardia are coincidental. The existence of two different tachycardias in the same patient almost always poses problems in the electrophysiology laboratory. However, in rare instances, the emergence of a second tachycardia can actually provide invaluable information about the first one. In this report, we describe a 30-year-old woman who presented with palpitations. Electrophysiological study revealed that atrial programmed stimulation at baseline induced right ventricular outflow tract (RVOT) tachycardia and supraventricular tachycardia. The study also showed that each of the tachycardias was able to induce the other. A short run of RVOT tachycardia during supraventricular tachycardia was able to entrain the latter. This finding provided important information about the nature of the supraventricular tachycardia, which proved to be atrioventricular nodal reentrant tachycardia. Both of these tachycardias were successfully ablated, and the patient’s palpitations disappeared

Orbits and reversals of a drop rolling inside a horizontal circular hydraulic jump

We explore the complex dynamics of a non-coalescing drop of moderate size inside a circular hydraulic jump of the same liquid formed on a horizontal disk. In this situation the drop is moving along the jump and one observes two different motions: a periodic one (it orbitates at constant speed) and an irregular one involving reversals of the orbital motion. Modeling the drop as a rigid sphere exchanging friction with liquid across a thin film of air, we recover the orbital motion and the internal rotation of the drop. This internal rotation is experimentally observed.Comment: 5 pages, 6 figure

En haut et au centre : la prééminence présidentielle

La prééminence présidentielle s'exprime spatialement à partir de deux concepts métaphoriques principaux : la hauteur et le centre. En fonction du contexte sémantique, les expressions métaphoriques convergent pour faire du président une figure centrale-prééminente de l'espace politique ou bien s'opposent pour éclairer différents aspects de l'institution.From a spatial viewpoint, the presidential pre-eminence can be expressed in two main metaphorical concepts: eminence and centrality. According to the semantic context, metaphorical expressions either converge to make the president a pre-eminent central figure in the political space or contradict each other to emphasize various aspects of the institution.El predominio presidencial se expresa espacialmente a travez de dos conceptos metafóricos esenciales : la altura y el centro. En función del contexto semántico, las expresiones metafóricas convergen para hacer del presidente un figura central-dominante del espacio político o se oponen para aclarar diversos aspectos de la institución

Destabilization of a Viscous Film Flowing Down in the Form of a Vertical Cylindrical Curtain

In this letter, we study experimentally a viscous liquid curtain in an annular geometry. Gap and median radius can be varied in such a way that the base of the initially stationary cylindrical curtain is led to oscillate by decreasing the flow rate. Standing and traveling waves in the plane of the annulus are observed and a non-trivial expression linking pulsation to flow rate per surface unit and viscosity can be defined

Oui ou non. Le piège rhétorique du référendum

Le dualisme de la réponse, « oui ou non », s’impose à tous les acteurs prenant part à une consultation référendaire. Oui et non ne constituent pas pour autant des mots vides dans un contexte de lutte politique. L’analyse des slogans de campagne pour le référendum sur le Traité constitutionnel européen montre comment la mise en slogan des réponses référendaires contribue à imposer le sens politique des votes « oui » et « non » par la mobilisation ou la neutralisation des ethos attachés à oui et à non tels qu’ils apparaissent dans les stratégies discursives des différents énonciateurs, en fonction de leur position dans le champ politique.Anyone taking part in a referendum can hardly escape the dualism of the “yes or no” reply.Yet within the context of a political struggle, the yes and no are by no means empty words. The analysis of the campaign slogans for the referendum on the European constitutional treaty shows to what extent making slogans for the referendum answers bears a part in compelling the yes and no choices to have specific political stands. This occurs through the mobilization or the neutralization of the ethos linked to the yes or the no as they appear in the discursive strategies of the various speakers and according to the positions such speakers hold within the political spectrum.El dualismo de la respuesta « sí o no » se impone a todos los actores que participan a una consulta referendaria. En un contexto de lucha política sí o no no constituyen por lo tanto palabras vacías. El análisis de los esloganes de campaña por el referéndum sobre el Tratado constitucional europeo muestra como la puesta en eslogan de las respuestas referendarias contribuye a imponer el sentido político de los votos « sí » y « no » a través de la mobilización o de la neutralización de los etos ligados al sí o al no tal como aparecen en las estrategias discursivas de diferentes enunciadores en función de su posición en el campo político

Evidence of slippage breakdown for a superhydrophobic microchannel

© 2014 AIP Publishing LLC.A full characterization of the water flow past a silicon superhydrophobic surface with longitudinal micro-grooves enclosed in a microfluidic device is presented. Fluorescence microscopy images of the flow seeded with fluorescent passive tracers were digitally processed to measure both the velocity field and the position and shape of the liquid-air interfaces at the superhydrophobic surface. The simultaneous access to the meniscus and velocity profiles allows us to put under a strict test the no-shear boundary condition at the liquid-air interface. Surprisingly, our measurements show that air pockets in the surface cavities can sustain non-zero interfacial shear stresses, thereby hampering the friction reduction capabilities of the surface. The effects of the meniscus position and shape as well as of the liquid-air interfacial friction on the surface performances are separately assessed and quantified

Quantifying effective slip length over micropatterned hydrophobic surfaces

We employ micro-particle image velocimetry ($\mu$-PIV) to investigate laminar micro-flows in hydrophobic microstructured channels, in particular the slip length. These microchannels consist of longitudinal micro-grooves, which can trap air and prompt a shear-free boundary condition and thus slippage enhancement. Our measurements reveal an increase of the slip length when the width of the micro-grooves is enlarged. The result of the slip length is smaller than the analytical prediction by Philip et al. [1] for an infinitely large and textured channel comprised of alternating shear-free and no-slip boundary conditions. The smaller slip length (as compared to the prediction) can be attributed to the confinement of the microchannel and the bending of the meniscus (liquid-gas interface). Our experimental studies suggest that the curvature of the meniscus plays an important role in microflows over hydrophobic micro-ridges.Comment: 8 page

Evidence of slippage breakdown for a superhydrophobic microchannel

© 2014 AIP Publishing LLC.A full characterization of the water flow past a silicon superhydrophobic surface with longitudinal micro-grooves enclosed in a microfluidic device is presented. Fluorescence microscopy images of the flow seeded with fluorescent passive tracers were digitally processed to measure both the velocity field and the position and shape of the liquid-air interfaces at the superhydrophobic surface. The simultaneous access to the meniscus and velocity profiles allows us to put under a strict test the no-shear boundary condition at the liquid-air interface. Surprisingly, our measurements show that air pockets in the surface cavities can sustain non-zero interfacial shear stresses, thereby hampering the friction reduction capabilities of the surface. The effects of the meniscus position and shape as well as of the liquid-air interfacial friction on the surface performances are separately assessed and quantified