Pacemapping

Pacemapping (PM) is an electrophysiologic technique designed to help locating tachycardia sources by stimulating at different endocardial sites in order to reproduce the clinical tachycardia characteristics. A recorded electrocardiogram (ECG) during the clinical tachycardia has been conventionally used as reference. Yet, endocardial activation pattern during tachycardia may be utilized as well to guide the procedure. In focal tachycardia ablation, PM guide has consistently provided remarkable outcomes1, while outcomes in reentrant tachycardia ablation are less favourabl

Self-diffusion coefficient of the square-well fluid from molecular dynamics within the constant force approach

We present a systematic study of the self-diffusion coefficient for a fluid of particles interacting via the square-well pair potential by means of molecular dynamics simulations in the canonical (N,V,T) ensemble. The discrete nature of the interaction potential is modeled through the constant force approximation and the self-diffusion coefficients is determined for several packing fractions at super critical thermodynamic states. The dependence of the self-diffusion coefficient with the potential range $\lambda$ is analyzed in the range of $1.1 \leq \lambda \leq 1.5$. The obtained molecular dynamics simulations results are in agreement with the self-diffusion coefficient predicted with the Enskog method. Additionally, we soh that the diffusion coefficient is very sensitive to the potential range, $\lambda$, at low densities leading to a density dependence of this coefficient not shared with other macroscopic properties such as the equation of state. The constant force approximation used in this work to model the discrete pair potential has shown to be an excellent scheme to compute the transport properties using standar computer simulations. Finally, the simulation results presented here are resourceful to improving theoretical approaches, such as the Enskog method

Nonexistence of conformally flat slices of the Kerr spacetime

Initial data for black hole collisions are commonly generated using the Bowen-York approach based on conformally flat 3-geometries. The standard (constant Boyer-Lindquist time) spatial slices of the Kerr spacetime are not conformally flat, so that use of the Bowen-York approach is limited in dealing with rotating holes. We investigate here whether there exist foliations of the Kerr spacetime that are conformally flat. We limit our considerations to foliations that are axisymmetric and that smoothly reduce in the Schwarzschild limit to slices of constant Schwarzschild time. With these restrictions, we show that no conformally flat slices can exist.Comment: 5 LaTeX pages; no figures; to be submitted to Phys. Rev.

Un texto médico del siglo XV el Tratado de las apostemas, de Diego el Covo.

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Capillary origami: superhydrophobic ribbon surfaces and liquid marbles

In the wetting of a solid by a liquid it is often assumed that the substrate is rigid. However, for an elastic substrate the rigidity depends on the cube of its thickness and so reduces rapidly as the substrate becomes thinner as it approaches becoming a thin sheet. In such circumstances, it has been shown that the capillary forces caused by a contacting droplet of a liquid can shape the solid rather than the solid shaping the liquid. A substrate can be bent and folded as a (pinned) droplet evaporates or even instantaneously and spontaneously wrapped on contact with a droplet. When this effect is used to create three dimensional shapes from initially flat sheets, the effect is called capillary origami or droplet wrapping. In this work, we consider how the conditions for the spontaneous, capillary induced, folding of a thin ribbon substrate might be altered by a rigid surface structure that, for a rigid substrate, would be expected to create Cassie–Baxter and Wenzel effects. For smooth thin substrates, droplet wrapping can occur for all liquids, including those for which the Young’s law contact angle (defined by the interfacial tensions) is greater than 90° and which would therefore normally be considered relatively hydrophobic. However, consideration of the balance between bending and interfacial energies suggests that the tendency for droplet wrapping can be suppressed for some liquids by providing the flexible solid surface with a rigid topographic structure. In general, it is known that when a liquid interacts with such a structure it can either fully penetrate the structure (the Wenzel case) or it can bridge between the asperities of the structure (the Cassie–Baxter case). In this report, we show theoretically that droplet wrapping should occur with both types of solid–liquid contact. We also derive a condition for the transition between the Cassie–Baxter and Wenzel type droplet wrapping and relate it to the same transition condition known to apply to superhydrophobic surfaces. The results are given for both droplets being wrapped by thin ribbons and for solid grains encapsulating droplets to form liquid marble

La novela histórica desde la perspectiva del año 2000.

El presente trabajo analiza algunos de los rasgos que configuran a la novela histórica como género literario. El estudio más pormenorizado de dos obras concretas (En busca del unicornio de Eslava Galán, y El mal amor de Fernán Gómez) permite no sólo precisar tales características, sino también destacar los riesgos y las posibilidades de este tipo de novelas

Una obra reciente sobre medicina y dulcería en el Libro de buen amor.

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Hipomotilidad gastrointestinal en conejos : 7 casos clínicos

Se describen siete casos clínicos de hipomotilidad gastrointestinal (HGI) en conejos mantenidos como mascotas. En todos los casos se intenta establecer la causa primaria que inició el proceso de HGI. Finalmente se discuten las ventajas e inconvenientes de cada una de las medidas terapéuticas aplicadas.