Quantifying rock fabrics: a test of autocorrelation of the spatial distribution of cristals

A novel test of spatial independence of the distribution of crystals or phases in rocks based on compositional statistics is introduced. It improves and generalizes the common joins-count statistics known from map analysis in geographic information systems. Assigning phases independently to objects in RD is modelled by a single-trial multinomial random function Z(x), where the probabilities of phases add to one and are explicitly modelled as compositions in the K-part simplex SK. Thus, apparent inconsistencies of the tests based on the conventional joins{count statistics and their possibly contradictory interpretations are avoided. In practical applications we assume that the probabilities of phases do not depend on the location but are identical everywhere in the domain of de nition. Thus, the model involves the sum of r independent identical multinomial distributed 1-trial random variables which is an r-trial multinomial distributed random variable. The probabilities of the distribution of the r counts can be considered as a composition in the Q-part simplex SQ. They span the so called Hardy-Weinberg manifold H that is proved to be a K-1-affine subspace of SQ. This is a generalisation of the well-known Hardy-Weinberg law of genetics. If the assignment of phases accounts for some kind of spatial dependence, then the r-trial probabilities do not remain on H. This suggests the use of the Aitchison distance between observed probabilities to H to test dependence. Moreover, when there is a spatial uctuation of the multinomial probabilities, the observed r-trial probabilities move on H. This shift can be used as to check for these uctuations. A practical procedure and an algorithm to perform the test have been developed. Some cases applied to simulated and real data are presented. Key words: Spatial distribution of crystals in rocks, spatial distribution of phases, joins-count statistics, multinomial distribution, Hardy-Weinberg law, Hardy-Weinberg manifold, Aitchison geometry

Intrinsic test of independence in contingency tables

A condition needed for testing nested hypotheses from a Bayesian viewpoint is that the prior for the alternative model concentrates mass around the small, or null, model. For testing independence in contingency tables, the intrinsic priors satisfy this requirement. Further, the degree of concentration of the priors is controlled by a discrete parameter m, the training sample size, which plays an important role in the resulting answer regardless of the sample size. In this paper we study robustness of the tests of independence in contingency tables with respect to the intrinsic priors with different degree of concentration around the null, and compare with other “robust” results by Good and Crook. Consistency of the intrinsic Bayesian tests is established. We also discuss conditioning issues and sampling schemes, and argue that conditioning should be on either one margin or the table total, but not on both margins. Examples using real are simulated data are given

Coherent forecasting of multiple-decrement life tables: a test using Japanese cause of death data

Planners in public and private institutions would like coherent forecasts of the components of age-specic mortality, such as causes of death. This has been di cult to achieve because the relative values of the forecast components often fail to behave in a way that is coherent with historical experience. In addition, when the group forecasts are combined the result is often incompatible with an all-groups forecast. It has been shown that cause-specic mortality forecasts are pessimistic when compared with all-cause forecasts (Wilmoth, 1995). This paper abandons the conventional approach of using log mortality rates and forecasts the density of deaths in the life table. Since these values obey a unit sum constraint for both conventional single-decrement life tables (only one absorbing state) and multiple-decrement tables (more than one absorbing state), they are intrinsically relative rather than absolute values across decrements as well as ages. Using the methods of Compositional Data Analysis pioneered by Aitchison (1986), death densities are transformed into the real space so that the full range of multivariate statistics can be applied, then back-transformed to positive values so that the unit sum constraint is honoured. The structure of the best-known, single-decrement mortality-rate forecasting model, devised by Lee and Carter (1992), is expressed in compositional form and the results from the two models are compared. The compositional model is extended to a multiple-decrement form and used to forecast mortality by cause of death for Japan

La creatividad poética: Reciclaje, conexiones y "collage"

La función lúdico-creativa del lenguaje es un eje fundamental en el currículo de la educación infantil, primaria y secundaria. La poesía ofrece el conocimiento, la posibilidad y el camino para adquirir esta función lingüística. La creación y el placer lingüístico requieren de un proceso de aprendizaje, análisis, reflexión e investigación que debemos promocionar entre los alumnos a partir de la intervención didáctica

Aprendizaje y evaluación de la competencia transversal "Creatividad e Innovación" en el marco de una titulación adaptada al EEES

Un aspecto primordial del cambio que ha supuesto la adaptación de las titulaciones al Espacio Europeo del Educación Superior (EEES) es que el proceso de aprendizaje se centra en el estudiante y resalta la importancia que representa la educación en términos de adquisición de diversas competencias. Para ofrecer una formación de calidad es indispensable evaluar el progreso de los estudiantes en dichas competencias utilizando instrumentos que permitan la mejora continua del aprendizaje a lo largo de toda la titulación. En el presente trabajo se expondrá la importancia que adquiere en el título de Grado en Administración y Dirección de Empresas (ADE) de la Universitat Ramon Llull (URL), la adquisición por parte de los estudiantes de la competencia transversal “Creatividad e Innovación” y los instrumentos de evaluación que se han diseñado para evaluar el progreso y logro de los estudiantes en dicha competencia durante su periodo formativo. Por una parte, se tratará la evaluación de la creatividad como competencia transversal del currículo de la titulación de ADE y en consecuencia, en el contexto global del plan de estudios de la titulación. Por otra parte, se describirá la evaluación de la creatividad en el marco específico de una asignatura para detallar el instrumento y criterios concretos de evaluación utilizados aplicados a una materia concreta. En las conclusiones se expondrá en qué medida el proceso de evaluación ha repercutido en la mejora del aprendizaje de la competencia y las acciones llevadas a cabo como resultados de la evaluación