Multiobjective solution of the uncapacitated plant location problem

In this paper we consider the discrete multiobjective uncapacitated plant location problem. We present an exact and an approximate approach to obtain the set of non-dominated solutions. The two approaches resort to dynamic programming to generate in an efficient way the non-dominated solution sets. The solution methods that solve the problems associated with the generated states are based on the decomposition of the problem on two nested subproblems. We define lower and upper bound sets that lead to elimination tests that have shown to have a high performance. Computational experiments on a set of test problems show the good performance of the proposal

The Single Period Coverage Facility Location Problem: Lagrangean heuristic and column generation approaches

In this paper we introduce the Single Period Coverage Facility Location Problem. It is a multi-period discrete location problem in which each customer is serviced in exactly one period of the planning horizon. The locational decisions are made independently for each period, so that the facilities that are open need not be the same in different time periods. It is also assumed that at each period there is a minimum number of customers that can be assigned to the facilities that are open. The decisions to be made include not only the facilities to open at each time period and the time period in which each customer will be served, but also the allocation of customers to open facilities in their service period. We propose two alternative formulations that use different sets of decision variables. We prove that in the first formulation the coefficient matrix of the allocation subproblem that results when fixing the facilities to open at each time period is totally unimodular. On the other hand, we also show that the pricing problem of the second model can be solved by inspection. We prove that a Lagrangean relaxation of the first one yields the same lower bound as the LP relaxation of the second one. While the Lagrangean dual can be solved with a classical subgradient optimization algorithm, the LP relaxation requires the use of column generation, given the large number of variables of the second model. We compare the computational burden for obtaining this lower bound through both models

Detección y caracerización de quinacridonas de altas prestaciones mediante espectroscopias moleculares (raman y fluorescencia) intensificadas por nanopartículas metálicas

El trabajo desarrollado en esta Tesis Doctoral aborda el estudio mediante técnicas ultrasensibles de espectroscopíamolecular (Raman y Fluorescencia intensificada por superficies metálicas nanoestructuradas, SERS y SEF, respectivamente) de derivados de las Quinacridonas (Quinacridona, 2,9-dimetilquinacridona, 2,9-dicloroquinacridona, N,N-dimetilquinacridona, N,N-diisoamilquinacridona y Quinacridona Quinona). La alta estabilidad química y fotoquímica de estos compuestos, su extremadamente baja solubilidad y sus atractivos colores, las hacen idóneas para su uso como pigmentos, utilizados ampliamente tanto en pinturas para trabajos artísticos como para ser aplicados en cualquier otra superficie. Al mismo tiempo los dispositivos fotovoltaicos y electroluminiscentes (OLEDs) requieren de su empleo como co-dopantes para mejorar su rendimiento y estabilidad debido a su alta capacidad de emisión fluorescente. Entre las técnicas experimentales que permiten la caracterización de materiales, en el campo de los pigmentos destacan la difracción de rayos X, UV-visible, HPLC (cromatografía líquida de alta resolución), la espectroscopía Raman e infrarrojo (IR). Las dos últimas presentan una serie de ventajas respecto a las anteriores; son técnicas no destructivas, no requieren extracción ni preparación de muestras, ofrecen la posibilidad de su aplicación in situ y dan una caracterización unívoca de los compuestos. Sin embargo para pigmentos orgánicos, incluidos las quinacridonas, presentan una serie de inconvenientes; la intensa señal de fluorescencia que presentan, solapando la señal Raman y la baja sensibilidad de la técnica. La espectroscopía SERS solventa ambos problema, por ello ha sido empleada para la caracterización de estos compuestos. En determinadas condiciones, la emisión fluorescente también puede ser intensificada, dando lugar al efecto SEF ( Fluorescencia intensificada por superficie), y siendo de gran interés para su aplicación en dispositivos OLED. Por ello, las N,N-dialquilquinacridonas se estudiaron también por ésta técnica. La insolubilidad en agua de las quinacridonas, y su baja o en ocasiones nula solubilidad en disolventes orgánicos, al mismo tiempo que el alto grado de agregación son un tremendo obstáculo para su estudio y caracterización mediante SERS constituyendo un verdadero reto. Por ello ha sido necesario desarrollar multitud de estrategias para alcanzar el objetivo deseado. Dichas estrategias involucran técnicas de funcionalización de superficies metálicas, métodos de dispersión y la búsqueda de las condiciones experimentales tales como soporte metálico, línea de excitación y agregantes. Para los estudios SEF, requirió la fabricación de soportes metálicos adecuados.Departamento de Física de la Materia Condensada, Cristalografía y Mineralogí

A modeling framework for ordered weighted average combinatorial optimization

Multiobjective combinatorial optimization deals with problems considering more than one viewpoint or scenario. The problem of aggregating multiple criteria to obtain a globalizing objective function is of special interest when the number of Pareto solutions becomes considerably large or when a single, meaningful solution is required. Ordered Weighted Average or Ordered Median operators are very useful when preferential information is available and objectives are comparable since they assign importance weights not to specific objectives but to their sorted values. In this paper, Ordered Weighted Average optimization problems are studied from a modeling point of view. Alternative integer programming formulations for such problems are presented and their respective domains studied and compared. In addition, their associated polyhedra are studied and some families of facets and new families of valid inequalities presented. The proposed formulations are particularized for two well-known combinatorial optimization problems, namely, shortest path and minimum cost perfect matching, and the results of computational experiments presented and analyzed. These results indicate that the new formulations reinforced with appropriate constraints can be effective for efficiently solving medium to large size instances.Ministerio de Educación y CienciaJunta de AndalucíaFondo Europeo de Desarrollo Regiona

Solution SERS of an insoluble synthetic organic pigment-quinacridone quinone-employing calixarenes as dispersive cavitands

3 páginas, 5 figuras.A possibility of getting SERS spectra of insoluble aromatic compounds in colloidal silver solutions is described. The method tested for the organic pigment quinacridone quinone consists of dispersing it in calix[n]arenes. The potentials of such cavitands, both as dispersing and as silver functionalization agents, is reported as a function of the substitution in their lower rim and their cavity size.This work has been financially supported by the Ministerio de Ciencia e Innovacio´n of Spain (Projects FIS2007-63065 and CONSOLIDER CSD2007-0058/TCP) and the Comunidad de Madrid (MICROSERES II Project S2009/TIC1476).Peer reviewe

De lo que aconteció cuando Martín Sarmiento se subió a la zebra del moro Muzaraque y encontró a Cervantes en el camino de Alcalá

This study remembers the importance Martín Sarmiento had in the discovery of Cervantes’ birthplace. As the authors explain, the novelty was not previously raised by Juan de Iriarte, as it was stated by his nephew in a letter published by Juan Antonio Pellicer. By the contrary, it was Sarmiento who found it in the spring of 1752, due to a triple coincidence: Firstly, the essay of the writing Sobre la Zebra, which drove Sarmiento to look documents and old Spanish texts up, to explain that zebras were hunted in Spain during the Middle Ages; secondly, the association of the word zebra with Cervantes in the Dictionary of the Real Academia Española; and thirdly, the acquisition of Haedo’s book on those dates. On the other hand, the authors indicate the nonexistence of information to demonstrate that Martinez Pingarrón got in before Agustin Montiano in obtaining the certificate of Cervantes’ baptism.En este estudio se recuerda la importancia que tuvo Martín Sarmiento en el descubrimiento de Alcalá como lugar de nacimiento de Cervantes. Según exponen los autores, la novedad no fue planteada previamente por Juan de Iriarte, como afirmó su sobrino en una carta publicada por Juan Antonio Pellicer, sino únicamente por el benedictino Sarmiento, debido a una triple coincidencia en la primavera de 1752: primero, la redacción del escrito Sobre la Zebra, que llevó a Sarmiento a consultar documentos y textos antiguos, para explicar que las cebras abundaban y se cazaban en la España medieval; segundo, la asociación de la cebra con Cervantes en el Diccionario de la Real Academia; y tercero, la adquisición de la obra de Diego de Haedo en esas mismas fechas. Los autores recuerdan, por otra parte, la inexistencia de datos que avalen que Martínez Pingarrón se anticipó a Agustín Montiano para conseguir la partida de bautismo de Cervantes

Determinants of Public Health Personnel Spending in Spain

Public health is funded with government funds gathered from tax revenues, whether national, provincial or municipal. The health system therefore suffers during economic crisis periods, whether due to disinvestment, loss of purchasing power among health care personnel or the decrease in the number of professionals. This worsens the situation, as it is necessary to cover the needs of an increasingly elderly population and with a longer life expectancy at birth. The present study intends to show a model which explains the determination of the "Public Health Personnel Expenditure" in Spain for a determined period. A multiple linear regression model was applied to the period including the years 1980-2021. Macroeconomic and demographic variables were analyzed to explain the dependent variable. Variation in health personnel expenditure: "We included those variables which presented a high or very high correlation above r > 0.6. The variables which explain the behavior of Variation in health personnel expenditure". It was a determining factor in the present study to consider that the variables with the greatest repercussions on health policy were mainly macroeconomic variables rather than demographic variables, with the only significant demographic variable that had a specific weight lower than macroeconomic variables being "Birth Rate". In this sense, the contribution made to the scientific literature is to establish an explanatory model so that public policy managers and states in particular can consider it in their public spending policies, bearing in mind that health expenditures in a Beveridge-style health system, as Spain has, are paid with funds drawn from tax revenues

Interaction between VA-ECMO and the right ventricle.

The response of the right ventricle (RV) to the hemodynamic effects of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is currently unpredictable. We hypothesized that the presence of uni- or bi-ventricular failure before implantation and the cannulation strategy may influence this interaction. We sought to assess the RV performance during VA-ECMO support and identify RV-related predictors of successful weaning. Changes in RV size and function during VA-ECMO support by echocardiography were retrospectively analyzed in 87 consecutive adult patients between February 2008 and June 2017. Predictors of successful weaning due to myocardial recovery were evaluated by multivariable logistic regression. RV echocardiographic parameters did not vary significantly during VA-ECMO support and neither after stratification by the type of cannulation or the presence of isolated or biventricular failure. Successful weaning was conditioned by the absence of RV dysfunction before implantation (OR, 14.7; 95% CI, 13.3-140.3; p = 0.025) or in the last day of support (OR, 9.5; 95% CI, 1.6-54; p = 0.011) and was favored by a total or partial recovery of RV function during the assistance (OR, 6.2; 95%CI, 1.7-22.4; p = 0.005). RV improvement was more often observed in patients with acute RV failure and longer support, while VA-ECMO configuration, additional mechanical support, or pharmacological therapy had no effect. Preservation or improvement of RV function during VA-ECMO is essential for successful weaning. RV echocardiographic performance does not change significantly during VA-ECMO support and is not influenced by cannulation type or the presence of uni- or bi-ventricular failure before implantation.This work was supported by the Alfonso Martin Escudero Foundation.S