Criterio para análisis de fatiga con tensiones aleatorias

[ES]El trabajo que aquí se presenta tiene como principal objetivo comprobar la validez del método de Osgood, que es una particularización del método de Palmgren-Miner, que se emplea cuando un punto de una pieza está sometido a tensiones aleatorias. Se quiere comprobar su validez en situaciones reales en las que no se cumplen algunas de sus hipótesis de partida. En concreto en este trabajo se va a analizar la validez del método en dos casos: cuando el registro de tensiones aplicado sobre la pieza es alterno pero no sigue una distribución Gaussiana y cuando ni es Gaussiano ni alterno. Los resultados obtenidos empleando el método de Osgood en ambos casos se compararán con el daño obtenido para el mismo registro de tensiones empleando un método de daño lineal como es el método de Palmgren-Miner. Para llevar a cabo esta comprobación se va a hacer uso del programa Excel, mediante el cual se generarán los registros de tensiones aleatorias con los que se va a trabajar.

Use of generalised additive models to categorise continuous variables in clinical prediction

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Seasonal Blowfly Distribution and Abundance in Fragmented Landscapes. Is It Useful in Forensic Inference about Where a Corpse Has Been Decaying?

Blowflies are insects of forensic interest as they may indicate characteristics of the environment where a body has been laying prior to the discovery. In order to estimate changes in community related to landscape and to assess if blowfly species can be used as indicators of the landscape where a corpse has been decaying, we studied the blowfly community and how it is affected by landscape in a 7,000 km(2) region during a whole year. Using baited traps deployed monthly we collected 28,507 individuals of 10 calliphorid species, 7 of them well represented and distributed in the study area. Multiple Analysis of Variance found changes in abundance between seasons in the 7 analyzed species, and changes related to land use in 4 of them (Calliphora vomitoria, Lucilia ampullacea, L. caesar and L. illustris). Generalised Linear Model analyses of abundance of these species compared with landscape descriptors at different scales found only a clear significant relationship between summer abundance of C. vomitoria and distance to urban areas and degree of urbanisation. This relationship explained more deviance when considering the landscape composition at larger geographical scales (up to 2,500 m around sampling site). For the other species, no clear relationship between land uses and abundance was found, and therefore observed changes in their abundance patterns could be the result of other variables, probably small changes in temperature. Our results suggest that blowfly community composition cannot be used to infer in what kind of landscape a corpse has decayed, at least in highly fragmented habitats, the only exception being the summer abundance of C. vomitoria.