Water quality as a limiting factor: Concepts and applications for the Mid-Ebro valley

The particular characteristics of the soil, the climate and the distrubution of water amongst the different types of use, all result in a specific problem for the management of the water resource in the arid and semi-arid areas of Spain, making it necessary to redefine tha notions of consumption, efficiency of use and water supply in accordance with new criteria that take the different qualities into account. This, in turn, leads to new meanings being given to terms such as scarcity, water deficit, etc. Within this framework, the objetive of the paper is twofold: first, to propose new concepts and measures that include qualitative aspects; secondly, to psesent an empirical approximation of these concepts, based on the water and socio-economic data for tha mid-Ebro Valley region of Northern Spain. Keywords: Water Economics, Water supply, Water management.

A case study of the relationship between high school students\u27 level of satisfaction, students\u27 academic achievement, and their interest to remain in school.

This study focuses on the relationship between high school students\u27 level of satisfaction, students\u27 academic achievement, and their level to remain in school. Many studies and researchers have been blaming the school system for its failure to recognize that variables or factors outside the school environment are taking place and affecting students\u27 level of satisfaction, academic achievement, and their interest to remain in school and complete a high school diploma. This study focuses on the base of students\u27 perceptions or expectations regarding their school environment and an examination of significant correlations among variables that might distinguish particular factors. A Likert Rating Scale was used to measure students\u27 level of satisfaction and their interest to remain in school. It was administered to 282 students. Student achievement was measured by their grades upon entering high school and the grades they received at the end of the marking period. The statistical analyses included frequencies for all variables, Chi-Squares, t-Test and Analyses of Variance, and multiple correlations. Four specific research questions guided the study. The analysis of the open-ended section of the survey instrument provided evidence that the students feel responsible for their success or failure in school. They acknowledge other sources that are interfering with their school work: lack of time to complete homework and personal/family problems, as well as peer pressure. Students\u27 responses showed evidence of satisfaction with the school environment. The more favorable the school environment is, the more likely students are to remain in school and move ahead. Students perceive their parents\u27 interest in their education is a main element in their satisfaction and motivation to remain in school. Students\u27 part-time and full-time jobs could contribute to both students\u27 level of satisfaction and dissatisfaction. It provides some valuable skills to the students, but in some cases it creates obstacles that make students fall behind in school. Students\u27 level of satisfaction was indeed related to students\u27 academic achievement and their interest to remain in school. They do want to finish high school

Planar Normal Sections on Isoparametric Hypersurfaces and the infinity laplacian

The present article is devoted to present a new characterization of the Cartan isoparametric hypersurfaces in terms of properties of the polynomial, that determines the algebraic set of planar normal sections on the homogeneous isoparametric hypersurfaces in spheres. We show that Cartan isoparametric hypersurfaces are the only homo- geneous isoparametric hypersurfaces in spheres for which the Innity Laplacian of the polynomial that denes the algebraic set of planar normal sections is the polynomial multiplied by the squared norm of the tangent vector. Since it is required for our work, we also give these polynomials for all homogeneous isoparametric hypersurfaces in spheres.Fil: Barros, Julio. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Matematicas; ArgentinaFil: Sanchez, Cristian Urbano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigación y Estudios de Matemática de Córdoba(p); Argentin

Water quality as a limiting factor: Concepts and applications for the Mid-Ebro valley

The particular characteristics of the soil, the climate and the distrubution of water amongst the different types of use, all result in a specific problem for the management of the water resource in the arid and semi-arid areas of Spain, making it necessary to redefine tha notions of consumption, efficiency of use and water supply in accordance with new criteria that take the different qualities into account. This, in turn, leads to new meanings being given to terms such as scarcity, water deficit, etc. Within this framework, the objetive of the paper is twofold: first, to propose new concepts and measures that include qualitative aspects; secondly, to psesent an empirical approximation of these concepts, based on the water and socio-economic data for tha mid-Ebro Valley region of Northern Spain. Keywords: Water Economics, Water supply, Water management

Regional productive structure and water pollution: An analysis using the input-output model

The objetive of this paper is to carry out an in-depth study of the structural relations that exist between economic and environmental variables, with particular reference to the water resource in the Ebro Valley (Spain). To that end, we employ the concepts and indicators derived from input-output analysis. Thus, we present a methodology to obtain the key sectors in water consumption and pollution, the forward and backward linkages, the elasticities and the trade-offs between water pollution and the economic variables of income and employment. We obtain the generating sub-systems of water pollution and refine its traditional indicators, thereby allowing the entry of the "anti-pollution sector". This supposes an advance, in that it allows the traditional input-output table to be orientated towards a new approach, one that is the more appropiate for the economic-environmental relationships. The application is made individually for the four regions of the Ebro Valley, as well as for an integrated input-output table for the complete Valley, with our aim being to describe the inter-sectoral productive relations and their impact on water, both within each economy and for the Valley as a whole. Keywords: water economics, water pollution, environmental input-output tables

Seasonal dynamic factor analysis and bootstrap inference : application to electricity market forecasting

Year-ahead forecasting of electricity prices is an important issue in the current context of electricity markets. Nevertheless, only one-day-ahead forecasting is commonly tackled up in previous published works. Moreover, methodology developed for the short-term does not work properly for long-term forecasting. In this paper we provide a seasonal extension of the Non-Stationary Dynamic Factor Analysis, to deal with the interesting problem (both from the economic and engineering point of view) of long term forecasting of electricity prices. Seasonal Dynamic Factor Analysis (SeaDFA) allows to deal with dimensionality reduction in vectors of time series, in such a way that extracts common and specific components. Furthermore, common factors are able to capture not only regular dynamics (stationary or not) but also seasonal one, by means of common factors following a multiplicative seasonal VARIMA(p,d,q)×(P,D,Q)s model. Besides, a bootstrap procedure is proposed to be able to make inference on all the parameters involved in the model. A bootstrap scheme developed for forecasting includes uncertainty due to parameter estimation, allowing to enhance the coverage of forecast confidence intervals. Concerning the innovative and challenging application provided, bootstrap procedure developed allows to calculate not only point forecasts but also forecasting intervals for electricity prices.Dynamic factor analysis, Bootstrap, Forecasting, Confidence intervals