994 resultados para Vidal de Battini


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The chemical composition of sediments and rocks, as well as their distribution at the Martian surface, represent a long term archive of processes, which have formed the planetary surface. A survey of chemical compositions by means of Compositional Data Analysis represents a valuable tool to extract direct evidence for weathering processes and allows to quantify weathering and sedimentation rates. clr-biplot techniques are applied for visualization of chemical relationships across the surface (“chemical maps”). The variability among individual suites of data is further analyzed by means of clr-PCA, in order to extract chemical alteration vectors between fresh rocks and their crusts and for an assessment of different source reservoirs accessible to soil formation. Both techniques are applied to elucidate the influence of remote weathering by combined analysis of several soil forming branches. Vector analysis in the Simplex provides the opportunity to study atmosphere surface interactions, including the role and composition of volcanic gases

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The application of Discriminant function analysis (DFA) is not a new idea in the study of tephrochrology. In this paper, DFA is applied to compositional datasets of two different types of tephras from Mountain Ruapehu in New Zealand and Mountain Rainier in USA. The canonical variables from the analysis are further investigated with a statistical methodology of change-point problems in order to gain a better understanding of the change in compositional pattern over time. Finally, a special case of segmented regression has been proposed to model both the time of change and the change in pattern. This model can be used to estimate the age for the unknown tephras using Bayesian statistical calibration

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Several eco-toxicological studies have shown that insectivorous mammals, due to their feeding habits, easily accumulate high amounts of pollutants in relation to other mammal species. To assess the bio-accumulation levels of toxic metals and their in°uence on essential metals, we quantified the concentration of 19 elements (Ca, K, Fe, B, P, S, Na, Al, Zn, Ba, Rb, Sr, Cu, Mn, Hg, Cd, Mo, Cr and Pb) in bones of 105 greater white-toothed shrews (Crocidura russula) from a polluted (Ebro Delta) and a control (Medas Islands) area. Since chemical contents of a bio-indicator are mainly compositional data, conventional statistical analyses currently used in eco-toxicology can give misleading results. Therefore, to improve the interpretation of the data obtained, we used statistical techniques for compositional data analysis to define groups of metals and to evaluate the relationships between them, from an inter-population viewpoint. Hypothesis testing on the adequate balance-coordinates allow us to confirm intuition based hypothesis and some previous results. The main statistical goal was to test equal means of balance-coordinates for the two defined populations. After checking normality, one-way ANOVA or Mann-Whitney tests were carried out for the inter-group balances

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Isotopic data are currently becoming an important source of information regarding sources, evolution and mixing processes of water in hydrogeologic systems. However, it is not clear how to treat with statistics the geochemical data and the isotopic data together. We propose to introduce the isotopic information as new parts, and apply compositional data analysis with the resulting increased composition. Results are equivalent to downscale the classical isotopic delta variables, because they are already relative (as needed in the compositional framework) and isotopic variations are almost always very small. This methodology is illustrated and tested with the study of the Llobregat River Basin (Barcelona, NE Spain), where it is shown that, though very small, isotopic variations comp lement geochemical principal components, and help in the better identification of pollution sources

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A compositional time series is obtained when a compositional data vector is observed at different points in time. Inherently, then, a compositional time series is a multivariate time series with important constraints on the variables observed at any instance in time. Although this type of data frequently occurs in situations of real practical interest, a trawl through the statistical literature reveals that research in the field is very much in its infancy and that many theoretical and empirical issues still remain to be addressed. Any appropriate statistical methodology for the analysis of compositional time series must take into account the constraints which are not allowed for by the usual statistical techniques available for analysing multivariate time series. One general approach to analyzing compositional time series consists in the application of an initial transform to break the positive and unit sum constraints, followed by the analysis of the transformed time series using multivariate ARIMA models. In this paper we discuss the use of the additive log-ratio, centred log-ratio and isometric log-ratio transforms. We also present results from an empirical study designed to explore how the selection of the initial transform affects subsequent multivariate ARIMA modelling as well as the quality of the forecasts

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Publicada con el apoyo de la Fundación Municipal de Cultura, Educación y Universidad Popular del Ayuntamiento de Gijón.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Aquest projecte fi de carrera es centra en un restaurant fictici i genèric anomenat "El Restaurant al Punt". Es tractarà d' una empresa que s' inicia en el sector hostaler amb tot un seguit de coneixements previs per part dels propietaris. L' objectiu principal que es preten assolir en aquest projecte és: desenvolupar l' anàlisi, dissenyar i implementar una aplicació informàtica que permeti gestionar el funcionament d' un restaurant

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Estudi sobre el treball realitzat durant els anys 2005 i 2006 en més de 300 ha de presseguers de l'Alt i el Baix Empordà que contempla aspectes biològics de C. capitata, la metodologia de seguiment i control utilitzada durant els dos anys, avaluacions realitzades a camp així com l’anàlisi de les dades obtingudes

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Resumen basado en la publicaci??n

Relevância:

10.00% 10.00%

Publicador:

Resumo:

En este vídeo se observan los diferentes aspectos de la geografía física, humana y económica de la comarca narceana. Tratan de acercar el entorno a los alumnos a través del estudio del rio Narcea. Se intercalan diversos tipos de música y texto con el siguiente guión: Introducción, datos generales, localización geográfica, extensión..; Estudio del ecosistema, flora y fauna; Población y economía, distribución, densidad, tipo de poblamiento, habitat, sectores productivos; Aspectos etnográficos, toponimia, lengua, tipo de vivienda, costumbres; Aspectos históricos y artísticos; Impacto medioambiental, conservación del entorno.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Relación de premiados con la Medalla de la Educación Aragonesa, la Cruz de José de Calasanz, las placas de reconocimiento y las medallas extraordinarias de educación del año 2010. Su objetivo es destacar a personas o instituciones que han destacado por su servicio a la educación aragonesa.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Relación de premiados con la Medalla de la Educación Aragonesa, la Cruz de José de Calasanz, las placas de reconocimiento y las medallas extraordinarias de educación del año 2011. Su objetivo es destacar a personas o instituciones que han destacado por su servicio a la educación aragonesa.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Seleccionado en la convocatoria: Ayudas a proyectos de innovación e investigación educativa en el campo de la educación permanente, Gobierno de Aragón 2008-09

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Seleccionado en la convocatoria: Ayudas a la innovación e investigación educativa en centros docentes de niveles no universitarios, Gobierno de Aragón 2009-10

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Seleccionado en la convocatoria: Ayudas a la innovación e investigación educativa en centros docentes de niveles no universitarios, Gobierno de Aragón 2010-11