Arcs on Determinantal Varieties

We study arc spaces and jet schemes of generic determinantal varieties. Using the natural group action, we decompose the arc spaces into orbits, and analyze their structure. This allows us to compute the number of irreducible components of jet schemes, log canonical thresholds, and topological zeta functions.Comment: 27 pages. This is part of the author's PhD thesis at the University of Illinois at Chicago. v2: Minor changes. To appear in Transactions of the American Mathematical Societ

An approach based on the geometric mean of basic quantitative and qualitative bibliometric indicators to evaluate and analyse the research performance of countries and institutions

We present a straightforward procedure to evaluate the scientific contribution of territories and institutions that combines the size-dependent geometric mean, Q, of the number of research documents (N) and citations (C), and a scale-free measure of quality, q=C/N. We introduce a Global Research Output (GRO-index) as the geometric mean of Q and q. We show that the GRO-index correlates with the h-index, but appears to be more strongly correlated with other well known, widely used bibliometric indicators. We also compute relative GRO-indexes (GROr) associated with the scientific production within research fields. We note that although total sums of GROr values are larger than the GRO-index, due to the non-linearity in the computation of the geometric means, both counts are nevertheless highly correlated. That enables us to make useful comparative analyses among territories and institutions. Furthermore, to identify strengths and weaknesses of a given country or institution, we compute a Relative Research Output count (RROr-index) to tackle variations of the C/N ratio across research fields. Moreover, by using a wealth-index also based on quantitative and qualitative variables, we show that the GRO and RRO indexes are highly correlated with the wealth of the countries and the states of the USA. Given the simplicity of the procedures introduced in this paper and the fact that their results are easily understandable by non-specialists, we believe they could become as useful for the assessment of the research output of countries and institutions as the impact factor is for journals or the h-index for individuals.Comment: Page 3: The formula for the p-index was wrong (but the right formula was used to draw Fig. 5a), as well as in P7 the formula for the quantitative and qualitative parameters related to the p-index. Fig 7: Japan was associated with Western and not Asian countries; in caption, we added: Green letters correspond to countries of former Soviet-Union and satellite countries. P16 L1,added:Except Japa

El entrenamiento reatribucional como intervención para la mejora del rendimiento académico

[Resumen] Se presenta una revisión sobre la función que desempeñan las atribuciones causales en el rendimiento académico. En primer lugar, se hace referencia a un ejemplo que muestra como la conducta y las emociones pueden cambiar al atribuir el mismo resultado a diferentes causas.- A continuación se describen las dimensiones principales en que pueden ser ordenadas las atribuciones causales.- De forma detallada se indican cuales son las consecuencias de los distintos tipos de explicaciones causales sobre la motivación, el estado emocional y la autoestima.- Por último, se hace mención de los estilos atribucionales que son adaptativos y desadaptativos para el rendimiento académico y la posibilidad de modificar estos últimos a través del feedback que proporciona el entrenamiento reatribucional

Análisis de las recuperaciones de Gaviota Tridáctila (Rissa tridactyla) en la Península Ibérica

S'estudien les recuperacions de gavineta de tres dits a la península Ibèrica a partir de l'anàlisi de les dades d'Espanya i Portugal. Un percentatge important de les recuperacions 60,9% (n=41) es produeixen al golf de Biscaia; la majoria de les recuperacions són d'ocells juvenils i es produeixen en el període novembre-gener. En aquesta àrea una part dels ocells moren a causa de les xarxes de pesca i caça. Al llarg de la costa atlàntica 11 recuperacions indicaren dispersió més enllà del golf de Biscaia, mentre que a la costa mediterrània només s'han produït quatre recuperacions. Al voltant d'un 80% de les recuperacions són d'ocells britànics amb un nombre important de gavines procedents de la colònia de les illes Farne