RESUMEN
We analyze the sensitivity of PP precursor traveltimes that are often used to infer lateral variation in the depths of the 410- and 660-km discontinuities in the mantle. Previous results were inconclusive due to complex wave phenomena, such as multiple energy conversions and focusing/defocusing, that hamper their interpretation. Using spectral-element synthetics and Fréchet derivatives calculated with adjoint methods, we compute sensitivity kernels for volumetric and boundary parameters in a 1-D model for representative epicentral distances of past studies, and a dominant period of 11-25 s. Our results indicate that the boundary sensitivity of PP precursors is low and that these phases are not coherently seen in exact synthetics. Our most important finding is the strong sensitivity to both shear and compressional wave speeds, indicating that wave interference and wave conversions are dominant. The PP precursor traveltimes appear more sensitive to structural parameters, that is, compressional and shear wave speed, than to the boundaries; therefore, they are unlikely sources for valuable insight into discontinuity topography.
RESUMEN
This study investigates elementary school children's prejudice towards obesity. A sample of 1861 underweight, normal, overweight and obese children from Central Greece were instructed to rank 6 drawings of same sex children with various physical disabilities, obesity or no disability at all ("healthy"), according to how much they liked each child. Results showed that all participants ranked the obese child last, showing that even obese individuals show negative attitudes towards obesity. Gender differences were recorded in almost all the drawings. Girls liked obese children and those with facial disfigurement less than boys did while boys disliked children with physical disabilities more than girls.