Publications

Displaying 1176 - 1200 of 1307

Publication	Date
An analytical proof of Hardy-like inequalities related to the Dirac operator Authors: Loss, Michael,Esteban, Maria J.,Dolbeault, Jean,Vega, Luis We prove some sharp Hardy type inequalities related to the Dirac operator by elementary, direct methods. Some of these inequalities have been obtained previously using spectral information about the Dirac-Coulomb operator. Our results are stated under optimal conditions on the asymptotics of the… Elsevier BV	2004-11-01
A three-dimensional model of moist convection for the giant planets II: Saturn's water and ammonia moist convective storms Authors: Ricardo Hueso,Agustín Sánchez-Lavega Abstract Moist convective storms constitute a key aspect in the global energy budget of the atmospheres of the giant planets. Among them, Saturn is known to develop the largest scale convective storms in the Solar System, the Great White Spots (GWS) which occur rarely and have been detected once… Elsevier BV	2004-11-01
Appropriateness variation in cholecystectomy Authors: José M. Quintana,José Luis Cabriada,Idoia Garay,Amaia Bilbao,Ignacio López De Tejada,Luis Perdigo,Inmaculada Arostegui Cholecystectomy use varies moderately across regions and countries. The purpose of this study was to evaluate the appropriateness of the use of cholecystectomy in patients with nonmalignant diseases in different hospitals using explicit criteria developed by an expert panel.Patients on waiting… Oxford University Press (OUP)	2004-09-01
Self-similar solutions of the localized induction approximation: singularity formation Authors: Susana Gutiérrez,Luis Vega 60 pages, 8 figures IOP Publishing	2004-08-07
Saturn's cloud morphology and zonal winds before the Cassini encounter Authors: Ricardo Hueso,Agustín Sánchez-Lavega,Richard G. French,Jose Félix Rojas,Santiago Pérez-Hoyos Abstract Analyses of Hubble Space Telescope (HST) images of Saturn obtained from August 2003 to March 2004, with extensive support from ground-based telescopes, have been used to characterize the cloud morphology and motions in its atmosphere few months before the Cassini encounter. We present… Elsevier BV	2004-08-01
The Cauchy problem for quasi-linear Schr�dinger equations Authors: Carlos E. Kenig,Luis Vega,Gustavo Ponce with x ∈ Rn, t ∈ R with ∇ = (∂x1, .., ∂xn) and summation convention. One may think of the equation in (1.1) as a non-linear Schrodinger equation where the operator modeling the dispersion relation is non-isotropic and depends also on the unknown function, its conjugate and their gradients in the… Springer Science and Business Media LLC	2004-06-09
The Magnetic Field in Giant Extrasolar Planets Authors: Agustín Sánchez-Lavega We study the internal structure and the convective motions of giant extrasolar planets in order to calculate their dynamo-generated surface magnetic field and dipolar magnetic moment. Using evolutionary models, we investigate the existence of magnetism in planets with masses ranging from 0.3MJ to… American Astronomical Society	2004-06-08
Erratum to: Quality-of-life outcomes with laparoscopic vs open cholecystectomy Authors: Amaia Bilbao,I. López de Tejada,José M. Quintana,José Luis Cabriada,Inmaculada Arostegui In the “Materials and methods” section, under the subheading “Statistical analysis,” it was stated that just patients with ASA IV were in the high surgical risk group, whereas the high surgical risk group included patients with ASA III and ASA IV. Springer Science and Business Media LLC	2004-06-01
Clouds in planetary atmospheres: A useful application of the Clausius–Clapeyron equation Authors: Santiago Pérez-Hoyos,Ricardo Hueso,Agustín Sánchez-Lavega The Clausius–Clapeyron equation is used to do a comparative study of the properties of the clouds that form in planetary atmospheres. Simple static atmospheric models for various planets, the satellite Titan, and the extrasolar planet HD209458b are used together with the saturation vapor pressure… American Association of Physics Teachers (AAPT)	2004-05-12
Smoothing and Word Sense Disambiguation Authors: Eneko Agirre,David Martinez This paper presents an algorithm to apply the smoothing techniques described in [15] to three different Machine Learning (ML) methods for Word Sense Disambiguation (WSD). The method to obtain better estimations for the features is explained step by step, and applied to n-way ambiguities. The… Springer Berlin Heidelberg	2004-01-01
UNSUPERVISED LEARNING OF BAYESIAN NETWORKS VIA ESTIMATION OF DISTRIBUTION ALGORITHMS: AN APPLICATION TO GENE EXPRESSION DATA CLUSTERING Authors: Pena, Jose,Lozano, J.A.,Larranaga, P. This paper proposes using estimation of distribution algorithms for unsupervised learning of Bayesian networks, directly as well as within the framework of the Bayesian structural EM algorithm. Both approaches are empirically evaluated in synthetic and real data. Specifically, the evaluation in… World Scientific Pub Co Pte Lt	2004-01-01
On the Interaction of Nearly Parallel Vortex Filaments Authors: Gustavo Ponce,Luis Vega,Carlos E. Kenig The system for the interaction of nearly parallel vortex filaments deduced by Klein, Majda and Damodaran is considered. Local existence for the associated initial value problem with data which are small perturbations of perfect parallel filaments is proved. Assumptions on the unperturbed… Springer Science and Business Media LLC	2003-12-01
Predictors of improvement in health-related quality of life in patients undergoing cholecystectomy Authors: I. López de Tejada,José Luis Cabriada,Luis Perdigo,José M. Quintana,Inmaculada Arostegui AbstractBackgroundFew studies have assessed health-related quality of life (HRQoL) among patients undergoing cholecystectomy. This study aimed to determine clinical variables that predict changes in HRQoL following cholecystectomy.MethodsThis was a prospective study of consecutive patients… Oxford University Press (OUP)	2003-11-03
EPIC simulations of the merger of Jupiter's White Ovals BE and FA: altitude-dependent behavior Authors: Agustín Sánchez-Lavega,Raul Morales-Juberias,Raul Morales-Juberias,Timothy E. Dowling Abstract Observations of the merger of Jupiter's White Ovals BE and FA show altitude-dependent behavior that we seek to capture in numerical simulations. In particular, it was observed that the upper portions of the vortices orbited each other before merging, but the lower portions translated… Elsevier BV	2003-11-01
Energy concentration and Sommerfeld condition for Helmholtz and Liouville equations Authors: Benoît Perthame,Luis Vega Abstract We consider the Helmholtz equation with a variable index of refraction n(x), which is not necessarily constant at infinity but can have an angular dependency like n(x)→n∞(x/\|x\|) as \|x\|→∞. We prove that the Sommerfeld condition at infinity still holds true under the weaker form 1 R… Cellule MathDoc/Centre Mersenne	2003-10-20
Averaging lemmas and the X-ray transform Authors: Pierre Emmanuel Jabin,Luis Vega Abstract We introduce a new method to prove averaging lemmas, i.e., prove a regularizing effect on the average in velocity of a solution to a kinetic equation. The method does not require the use of Fourier transform and the whole procedure is performed in the ‘real space’; it leads to estimating… Cellule MathDoc/Centre Mersenne	2003-10-15
On unique continuation for nonlinear Schrödinger equations Authors: Gustavo Ponce,Carlos E. Kenig,Luis Vega Wiley	2003-06-20
A strong decrease in Saturn's equatorial jet at cloud level Authors: Agustín Sánchez-Lavega,Richard G. French,Ricardo Hueso,Santiago Pérez-Hoyos,Jose Félix Rojas The atmospheres of the giant planets Jupiter and Saturn have a puzzling system of zonal (east-west) winds alternating in latitude, with the broad and intense equatorial jets on Saturn having been observed previously to reach a velocity of about 470 m x s(-1) at cloud level. Globally, the location… Springer Science and Business Media LLC	2003-06-05
Scattering of cylindrical thermal waves in fiber composites: In-plane thermal diffusivity Authors: R. Celorrio,Agustín Sánchez-Lavega,Agustín Salazar In this article, we present a general solution for the ac temperature field of an opaque material containing aligned subsurface cylinders produced by a modulated line illumination parallel to the cylinders. This work completes the case of plane illumination treated in a previous paper [J. M. Terrón… AIP Publishing	2003-04-15
Sommerfeld condition for a Liouville equation and concentration of trajectories Authors: Benoît Perthame,Luis Vega We analyse the concentration of trajectories in a Liouville equation set in the full space with a potential which is not constant at infinity. Our motivation comes from geometrical optics where it appears as the high freqency limit of Helmholtz equation. We conjecture that the mass and energy… Springer Science and Business Media LLC	2003-04-01
Evaluation of the psychometric characteristics of the Spanish version of the Hospital Anxiety and Depression Scale Authors: Angel Padierna,Cristóbal Esteban,Amaia Bilbao,Inmaculada Arostegui,José M. Quintana,Irune Ruiz Objective: To assess the psychometric properties of the Spanish version of the Hospital Anxiety and Depression Scale(HADS).Method: We administered HADS to 685 participants (256 controls and 429 patients with five different diagnoses). The reliability of the instrument was assessed by a test–… Wiley	2003-02-07
Formation of Singularities and Self-Similar Vortex Motion Under the Localized Induction Approximation† Authors: Judith Rivas,Susana Gutiérrez,Luis Vega The dynamical behavior of an isolated vortex filament in three dimensions within the localized induction approximation (LIA) is investigated. It is shown the existence of a uniparametric family of ... Informa UK Limited	2003-01-07
Variable search space for software testing Authors: Jose A. Lozano,Ramón Sagarna Testing is an essential phase in the software life cycle. One of the most important tasks testing involves is the automatic generation of the test inputs. The field of evolutionary testing aims at solving this task by means of combinatorial optimization search methods. An evolutionary testing based… IEEE	2003-01-01
Relation between estimates of myocardial ischemia using high resolution electrocardiography and scintigraphic images Authors: R. Groshon,Michael Ringborn,Elisabete Aramendi,Leif Sörnmo,Paul Lander,Ralph Lazzara,Galen S. Wagner Presents some preliminary data suggesting that acute myocardial ischemia may be uniquely detectable in the QRS complex of the high resolution ECG. It is hypothesized that acute ischemia may create functional block, leading to ischemically-altered ventricular activation patterns. The study assessed… IEEE	2002-12-24
A Comparative Study of Jovian Cyclonic Features from a Six-Year (1994–2000) Survey Authors: Morales-Juberías, Raúl,Sánchez-Lavega, Agustín,Lecacheux, Jean,Colas, François International audience Elsevier BV	2002-12-01