The synthesis, characterization, and magnetic properties of water-soluble Pd nanoparticles capped with glutathione are described. The glutathione-capped Pd nanoparticles were synthesized under argon and air atmospheres at room temperature. Whereas the former exhibits a bulklike lattice parameter, the lattice parameter of the latter is found to be considerably greater, indicating anomalous lattice expansion. Comparative structural and compositional studies of these nanoparticles suggest the presence of oxygen in the core lattice when Pd nanoparticles are prepared under an air atmosphere. Both Pd nanoparticles prepared under argon and air show ferromagnetism at 5 K, but the latter exhibits significantly greater coercivity (88 Oe) and magnetization (0.09 emu/g at 50 kOe). The enhanced ferromagnetic properties are explained by the electronic effect of the incorporated oxygen that increases the 4d density of holes at the Pd site and localizes magnetic moments.

No abstract

We investigate pediatric tumor incidence data collected by the Florida Association for Pediatric Tumor program using various models commonly used in disease mapping analysis. Particularly, we consider Poisson normal models with various conditional autoregressive structure for spatial dependence, a zero-inflated component to capture excess zero counts and a spatio-temporal model to capture spatial and temporal dependence, together. We found that intrinsic conditional autoregressive model provides the smallest Deviance Information Criterion (DIC) among the models when only spatial dependence is considered. On the other hand, adding an autoregressive structure over time decreases DIC over the model without time dependence component. We adopt weighted ranks squared error loss to identify high risk regions which provides similar results with other researchers who have worked on the same data set (e.g. Zhang et al., 2014;Wang and Rodriguez, 2014). Our results, thus, provide additional statistical support on those identified high risk regions discovered by the other researchers.