Existence, Uniqueness and Convergence of Simultaneous Distributed-Boundary Optimal Control Problems

We consider a steady-state heat conduction problem $P$ for the Poisson equation with mixed boundary conditions in a bounded multidimensional domain $\Omega$. We also consider a family of problems $P_{\alpha}$ for the same Poisson equation with mixed boundary conditions being $\alpha>0$ the heat transfer coefficient defined on a portion $\Gamma_{1}$ of the boundary. We formulate simultaneous \emph{distributed and Neumann boundary} optimal control problems on the internal energy $g$ within $\Omega$ and the heat flux $q$, defined on the complementary portion $\Gamma_{2}$ of the boundary of $\Omega$ for quadratic cost functional. Here the control variable is the vector $(g,q)$. We prove existence and uniqueness of the optimal control $(\overline{\overline{g}},\overline{\overline{q}})$ for the system state of $P$, and $(\overline{\overline{g}}_{\alpha},\overline{\overline{q}}_{\alpha})$ for the system state of $P_{\alpha}$, for each $\alpha>0$, and we give the corresponding optimality conditions. We prove strong convergence, in suitable Sobolev spaces, of the vectorial optimal controls, system and adjoint states governed by the problems $P_{\alpha}$ to the corresponding vectorial optimal control, system and adjoint states governed by the problem $P$, when the parameter $\alpha$ goes to infinity. We also obtain estimations between the solutions of these vectorial optimal control problems and the solution of two scalar optimal control problems characterized by fixed $g$ (with boundary optimal control $\overline{q}$) and fixed $q$ (with distributed optimal control $\overline{g}$), respectively, for both cases $\alpha>0$ and $\alpha=\infty$.Comment: 14 page

A free boundary model for oxygen diffusion in a spherical medium

The goal of this article is to find a correct approximated solution using a polynomial of sixth degree for the free boundary problem corresponding to the diffusion of oxygen in a spherical medium with simultaneous absorption at a constant rate, and to show some mistakes in previously published solutions.Comment: 10 pages, 6 figures and 2 tables. Paper accepted, in press in Journal of Biological Systems (2015

The first INTEGRAL-OMC catalogue of optically variable sources

The Optical Monitoring Camera (OMC) onboard INTEGRAL provides photometry in the Johnson V-band. With an aperture of 50 mm and a field of view of 5deg x 5deg, OMC is able to detect optical sources brighter than V~18, from a previously selected list of potential targets of interest. After more than nine years of observations, the OMC database contains light curves for more than 70000 sources (with more than 50 photometric points each). The objectives of this work have been to characterize the potential variability of the objects monitored by OMC, to identify periodic sources and to compute their periods, taking advantage of the stability and long monitoring time of the OMC. To detect potential variability, we have performed a chi-squared test, finding 5263 variable sources out of an initial sample of 6071 objects with good photometric quality and more than 300 data points each. We have studied the periodicity of these sources using a method based on the phase dispersion minimization technique, optimized to handle light curves with very different shapes.In this first catalogue of variable sources observed by OMC, we provide for each object the median of the visual magnitude, the magnitude at maximum and minimum brightness in the light curve during the window of observations, the period, when found, as well as the complete intrinsic and period-folded light curves, together with some additional ancillary data.Comment: Accepted by Astronomy & Astrophysics; 13 pages, 16 figures. Figures' resolution has been degraded to fit astro-ph constraint

Descriptive and spatial epidemiology of bovine cysticercosis in North-Eastern Spain (Catalonia).

From March 2005 to December 2007, 284 animals from 67 cattle farms (24 dairy and 43 beef) affected by bovine cysticercosis were detected in the region of Catalonia (North-Eastern Spain). Dairy farms were almost twice more likely to be affected than beef farms (OR=1.79, 95% CI=1.08-2.96, p<0.05), and infected premises have a statistically significant (p<0.05) larger number of animals when compared to uninfected farms in Catalonia. The geographical distribution of the infected farms was evaluated and two statistically significant clusters were identified. The most likely cluster was located in the western part of the study region, with 8 out of 10 farms infected. Epidemiological investigations revealed that the 8 farms belonged to the same company. The secondary cluster was located in Eastern Catalonia with 12 infected farms out of 167 cattle farms. No epidemiological links were found among the 12 infected premises. A questionnaire, based on the EFSA risk assessment, was used to assess the most likely route of introduction into each affected farm. Water supply for animals was the route with the highest score in 41.8% of the cases

Thoughts Regarding The Situation Of The Pediatric Cardiovascular Surgery In Brazil

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The INTEGRAL-OMC Scientific Archive

The Optical Monitoring Camera (OMC) on-board the INTEGRAL satellite has, as one of its scientific goals, the observation of a large number of variable sources previously selected. After almost 6 years of operations, OMC has monitored more than 100 000 sources of scientific interest. In this contribution we present the OMC Scientific Archive (http://sdc.laeff.inta.es/omc/) which has been developed to provide the astronomical community with a quick access to the light curves generated by this instrument.We describe the main characteristics of this archive, as well as important aspects for the users: object types, temporal sampling of light curves and photometric accuracy.Comment: 4 pages, 5 figures. "Highlights of Spanish Astrophysics V" Proceedings of the VIII Scientific Meeting of the Spanish Astronomical Society (SEA) held in Santander, July 7-11, 200

Thoughts regarding the situation of the pediatric cardiovascular surgery in Brazil

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