The chemical variability at the surface of Mars: implications for exogenic processes

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

Los Métodos para el estudio del violonchelo en la etapa inicial: análisis comparativo

En la actualidad se siguen utilizando en los centros de enseñanza musical (Escuelas de Música y Conservatorios) métodos de aprendizaje de iniciación de violonchelo que fueron escritos en el siglo XIX y principios del XX. La principal motivación de este estudio es conocer de qué forma y en qué aspectos puede repercutir el uso de determinados métodos en el proceso de enseñanza-aprendizaje del violonchelo. Se plantea un análisis comparativo de cuatro métodos de iniciación utilizados en la actualidad y escritos en diferentes épocas