Resumen: We consider a free boundary problem related to a stationary flow of fresh and salt water in a coastal aquifer. The flow is governed by a nonlinear Darcy’s law.
Existence and uniqueness of a monotone solution are proved.
Resumen: In this note we study a basic propagation criterion for quasi-static crack evolution in Mode III. Using classical techniques of complex analysis, the assumption of stable
growth is expressed in terms of the parameters defining the elastic field around the tip. We explore the consequences of the local condition obtained and analyse its role as a crack propagation law. In particular,
we herein extend to bounded domains a number of results previously obtained for the whole plane.
Palabras clave: Anti-symmetry principle, Quasistatic crack growth, Linear elasticity, Brittle material, Anti-plane fields, Configurational forces, Crack propagation law
Resumen: Contexto: CARMENES es un espectrógrafo echelle de última generación que ha sido diseñado específicamente para buscar exotierras alrededor de enanas con tipo espectral M. Objetivos: Ayudar a crear una lista de estrellas adecuadas (CARMENCITA) para ser observadas con CARMENES y caracterizarlas.
Métodos: Se han seleccionado las estrellas que cumplían los requisitos especificados de los catálogos Research Consortium
on Nearby Stars y Palomar/Michigan State University. Cada una de ellas ha sido revisada individualmente mediante la herramienta de observatorio virtual Aladin, tomándose sus coordenadas, fotometría JHKs y características más relevantes. Además, todos los sistemas binarios o múltiples encontrados durante el trabajo se han estudiado con detalle mediante Aladin y Washington Double Star catalog, registrando la información de todas sus componentes. A partir de ellos se ha analizado la ley de Öpik con el test de Kolmogorov-Smirnov y se han probado distribuciones de probabilidad alternativas.
Resultados: Se han estudiado y caracterizado individualmente 1044 estrellas M, así como todas sus compañeras en los más de 180 sistemas múltiples encontrados. En total más de 1300 estrellas. Hemos aceptado en nuestra base de datos un total de 915, a partir de las cuales se seleccionarán 300 que serán la muestra definitiva que observará CARMENES. Por otro lado, se ha obtenido el valor de aceptación del test de Kolmogorov-Smirnov en 24 intervalos de separaciones diferentes para la ley de Öpik así como para 10 hipótesis de distribuciones alternativas, encontrándose mejores resultados para intervalos más amplios con distribuciones del tipo S elevado a -λ+1, con -λ+1=0.1 y -λ+1=0.2 .
Conclusiones: La selección y estudio manual de las estrellas M ha sido fundamental para construir CARMENCITA, ya que ha sido un 5% más efectiva que los métodos automatizados. Además, se han corroborado los resultados de Poveda y Allen (2004) en lo que se refiere a la ley de Öpik, pero los resultados obtenidos para las hipótesis alternativas indican que nuestra muestra se describe mejor con un valor de −λ+1 entre 0.1 y 0.2.
[ABSTRACT]Context: CARMENES is a last generation echelle spectrograph specifically designed to search for exo-earths around M dwarfs.
Aims: To help to create a list of suitable and characterized stars (CARMENCITA) in order to be observed by CARMENES.
Methods: The stars have been selected according with the requirements specified at Research Consortium On Nearby Stars and Palomar/Michigan State University catalogs. Each star has been individually reviewed by the virtual observatory tool Aladin –taking its coordinates, JHKs photometry and its most relevant characteristics. In addition, all binary or multiple systems found during the work have been studied in depth recording information from all its components by Aladin and Washinton Double Star
catalog. Öpik’s law has been analyzed from them using the Kolmogorov-Smirnov test and others alternative probability distributions have been tested too.
Results: 1044 stars, as well as its partners at the more of 180 multiple systems found, have been studied and individually characterized, that is more than 1,300 stars. A total of 915 stars have been accepted in our data base, from which we will select a definitive sample of 300 stars that will be observed by CARMENES. In the other hand, we have obtained the value of acceptation from the Kolmogorov-
Smirnov test in 24 different intervals for the Öpik’s law, as for 10 hypothesis of alternative distributions, finding better results for longer intervals with S Raised a
-λ+1, con -λ+1= 0.1 y -λ+1= 0.2.
distributions.
Conclusions: The selection and the manual study of the M stars have been essential in order to build CARMENCITA, it has been 5% more effective than the automated methods. In addition, the results from Poveda & Allen (2004) have been verified at the Öpik’s law, but the results obtained for the
alternative hypothesis show that our sample is detailed better with a value of -λ+1 between 0.1 and 0.2.
Palabras clave: Bases de Datos Astronómicas, Infrarrojos: Sistemas Planetarios, Estrellas: Binarias, Estrellas: Baja Masa, Astronomical Data Bases, Infrared: Planetary Systems, Stars: Binaries, Stars: Low-Mass
Resumen: The dynamics of line singularities in three different physical systems are considered, namely vortices in an inviscid fluid, vortices in a type-II superconductor, and dislocations in an elastic crystal. When the core of the singularity can be regularized with a
continuum model, as is the case for superconducting and fluid vortices, the dynamics can be derived systematically in the asymptotic limit as the core radius tends to zero. The asymptotic analysis is more difficult when the core of the singularity is so small as to demand an atomic model, as is the case for dislocations, where the derivation of a law of motion is still an open problem in the mathematical sense.
Resumen: We present the first numerical solutions of a kinetic theory description of self-sustained current oscillations in n-doped semiconductor superlattices. The governing equation is a single-miniband Boltzmann-Poisson transport equation with a BGK (Bhatnagar-Gross-Krook) collision term. Appropriate boundary conditions for the distribution function describe electron
injection in the contact regions. These conditions seamlessly become Ohm's law at the injecting contact and the zero charge boundary condition at the receiving contact when integrated over the wave vector. The time-dependent model is numerically solved for the distribution function by using the deterministic Weighted Particle Method. Numerical simulations are used to ascertain the convergence of the method. The numerical results confirm the validity of the Chapman-Enskog perturbation method used previously to derive generalized drift-diffusion equations for high electric fields because they agree very well with numerical solutions thereof.
Resumen: In this work we have modeled the thermal structure of the lithosphere of the Spanish Central System
and the Tajo Basin, and their implications for lithospheric strength. For this, we have used refined heatproducing
elements (HPE) values to obtain new estimates of heat production rates in the Spanish Central
System
and Tajo Basin areas, which have been used joined to the relation between topography and
thermal structure of the lithosphere to calculate the best-fit surface heat flows in the study area. Moreover,
we have implemented a temperature-dependent thermal conductivity (appropriate for olivine) for the
lithospheric mantle to improve the calculations of temperature profiles in the mantle. The geotherms so
obtained, together with the implementation of a new rheological law for the upper lithospheric mantle,
have been used to calculate refined estimations of the strength and effective elastic thickness of the
lithosphere. We have obtained surface heat flow values of 84 mW m−2 and
∼82 mW m−2 for the Spanish
Central System and the Tajo Basin, respectively. The thermal state of the lithosphere affects mantle
temperatures, and hence may be playing an important role in the uplift and maintenance of the Spanish
Central System.
