In this paper a new approach of the Markowitz's model is presented. Indeed, using an inner product, a quantitative and explicit solution for optimal portfolio selection is given. To do this, a scalar product is defined in which allows us to calculate the composition of the optimal portfolio and...

Last decades qualitative variables have been introduced in the economic growth analysis. The improvement of statistical information has favored this task. Recently, “entrepreneurship” concept has been considered in this type of analysis. Entrepreneurship considers the capacity and ability to...

Este artículo presenta una revisión de los estudios y ensayos disponibles sobre los costes de producción de biomasa forestal en el norte de España, particularmente, los de la denominada biomasa forestal primaria residual. Se analiza el papel de la biomasa en la economía forestal, así como...

Solar energy for the production of electric energy is one source of renewable energy which is experiencing most development in recent years. In countries with high solar radiation indices, as is the case of Spain, expectations of installation of large solar power plants are increasing. Most...

The positive and negative predictive values of a binary diagnostic test are measures of the clinical accuracy of the diagnostic test, which depend on the sensitivity and specificity of the diagnostic test and the disease prevalence, and therefore they are two interdependent parameters. The...

We study the scaling properties of forced folding of thin materials of different geometry. The scaling relations implying the topological crossovers from the folding of three-dimensional plates to the folding of two-dimensional sheets, and further to the packing of one-dimensional strings, are...

We analyze the effect of spatial heterogeneity in the initial spin distribution on spin dynamics in a three-state square lattice divided into spatial cells (districts). In the spirit of the statistical mechanics of social impact, we introduce a dominant influence rule (DIR), according to which,...

Existen múltiples índices para medir la falta de autonomía de un individuo, especialmente en la literatura médica, que realizan una valoración parcial centrada en determinados aspectos. Este trabajo pretende superar esta restricción proponiéndose un índice que recoja todas las...

This paper analyses the factors leading to CO2 emissions in the Spanish electricity generation sector in order to propose effective mitigation policies aimed at tackling those emissions. Traditionally, two broad categories of those factors have been considered in the literature: those related to...

The European crisis has highlighted the role of intra-European payments imbalances for the survival of the EMU. Payment imbalances between the North and the South have contributed to the accumulation of large stock of foreign debt, while flows of foreign capital ceased to finance productive...