The formulation of a fully compressible nonhydrostatic atmospheric model called the Model for Prediction Across Scales-Atmosphere (MPAS-A) is described. The solver is discretized using centroidal Voronoi meshes and a C-grid staggering of the prognostic variables, and it incorporates a split-explicit time-integration technique used in many existing nonhydrostatic meso-and cloud-scale models. MPAS can be applied to the globe, over limited areas of the globe, and on Cartesian planes. The Voronoi meshes are unstructured grids that permit variable horizontal resolution. These meshes allow for applications beyond uniform-resolution NWP and climate prediction, in particular allowing embedded high-resolution regions to be used for regional NWP and regional climate applications. The rationales for aspects of this formulation are discussed, and results from tests for nonhydrostatic flows on Cartesian planes and for large-scale flow on the sphere are presented. The results indicate that the solver is as accurate as existing nonhydrostatic solvers for nonhydrostatic-scale flows, and has accuracy comparable to existing global models using icosahedral (hexagonal) meshes for large-scale flows in idealized tests. Preliminary full-physics forecast results indicate that the solver formulation is robust and that the variable-resolution-mesh solutions are well resolved and exhibit no obvious problems in the mesh-transition zones.

Kinetic energy (KE) spectra derived from global high-resolution atmospheric simulations from the Model for Prediction Across Scales (MPAS) are presented. The simulations are produced using quasi-uniform global Voronoi horizontal meshes with 3-, 7.5-, and 15-km mean cell spacings. KE spectra from the MPAS simulations compare well with observations and other simulations in the literature and possess the canonical KE spectra structure including a very-well-resolved shallow-sloped mesoscale region in the 3-km simulation. There is a peak in the vertical velocity variance at the model filter scale for all simulations, indicating the underresolved nature of updrafts even with the 3-km mesh. The KE spectra reveal that the MPAS configuration produces an effective model resolution (filter scale) of approximately 6Δx. Comparison with other published model KE spectra highlight model filtering issues, specifically insufficient filtering that can lead to spectral blocking and the production of erroneous shallow-sloped mesoscale tails in the KE spectra. The mesoscale regions in the MPAS KE spectra are produced without use of kinetic energy backscatter, in contrast to other results reported in the literature. No substantive difference is found in KE spectra computed on constant height or constant pressure surfaces. Stratified turbulence is not resolved with the vertical resolution used in this study; hence, the results do not support recent conjecture that stratified turbulence explains the mesoscale portion of the KE spectrum.

Human bocavirus (HBoV)-2, a new parvovirus, has been identified in stool samples and is suggested to be one of the etiologic agents of acute gastroenteritis (GE). The purpose of this study was to investigate the prevalence of HBoV-2 in children with GE. Stool samples were collected from 358 children hospitalized with GE. HBoV-2 was detected in 3.6% of the patients. HBoV-2 was co-detected with other viral agents in 53.8% of the patients. These findings suggest that HBoV-2 may be an etiologic agent in GE, but further studies are needed due to frequent co-detection with other enteric viruses.

This letter introduces conducting polymer compositions which can be used for hole-injection layer in organic light-emitting diodes. The compositions are composed of poly (3,4-ethylenedioxythiophene) (PEDOT), polystyrene sulfonic acid (PSS) and a perfluorinated ionomer. The films based on these compositions showed much higher workfunction (∼5.3–5.7eV) than conventional PEDOT/PSS (∼5.0–5.2eV). When we fabricated blue polymer light-emitting diodes by using these compositions as a hole-injection layer, the luminescent efficiency was improved and the device lifetime was also enhanced relative to the device using the commercially available PEDOT/PSS. These compositions including perfluorinated ionomers can be one of the promising candidates for a hole-injection layer in organic light-emitting devices.

Idealized normal-mode baroclinic wave simulations are conducted to examine the impact of continuous mesh refinement compared with stepwise changes in resolution using nested grids. The nested-grid results are produced using the Advanced Research Weather Research and Forecasting (WRF-ARW) Model, hereafter ARW, and the continuous refinement results are produced using the atmospheric component of the Model for Prediction Across Scales-Atmosphere (MPAS-A). For the nested domain simulations with the ARW, variants of both one-way and two-way nesting techniques are examined. Significant reflection and distortion of waves are evident in results using one-way nesting, with the error increasing with decreasing boundary-update frequency. With continuous updating of the boundary conditions in one-way and two-way nesting, wave distortion is still evident near the lateral boundaries but the distortion is much less than with infrequent boundary updates. The conformal Voronoi meshes in MPAS provide a much smoother transition between mesh resolutions. Variableresolution mesh MPAS-A simulations, using different transition zones between high-and low-resolution regions, are compared with the results from the ARW simulations. In the MPAS-A simulations, there is no significant reflection of gravity waves, suggesting that continuous mesh refinement can eliminate distortions that tend to occur along the boundaries of nested meshes.