Sea breeze: Induced mesoscale systems and severe weather

Sea-breeze-deep convective interactions over the Florida peninsula were investigated using a cloud/mesoscale numerical model. The objective was to gain a better understanding of sea-breeze and deep convective interactions over the Florida peninsula using a high resolution convectively explicit model and to use these results to evaluate convective parameterization schemes. A 3-D numerical investigation of Florida convection was completed. The Kuo and Fritsch-Chappell parameterization schemes are summarized and evaluated

Handedness, Health and Cognitive Development: Evidence from Children in the NLSY

Using data from the US National Longitudinal Survey of Youth, and fitting family fixed-effects models of child health and cognitive development, we test if left-handed children do significantly worse than their right-handed counterparts. The health measures cover both physical and mental health, and the cognitive development test scores span (1) Memory, (2) Vocabulary, (3) Mathematics, (4) Reading and (5) Comprehension. We find that while left-handed children have a significantly higher probability of suffering an injury needing medical attention, there is no difference in their experience of illness or poor mental health. We also find that left-handed children have significantly lower cognitive development test scores than right-handed children for all areas of development with the exception of reading. Moreover, the left-handedness disadvantage is larger for boys than girls, and remains roughly constant as children grow older for most outcomes. We also find that the probability of a child being left-handed is not related to the socioeconomic characteristics of the family, such as income or maternal education. All these results tend to support a difference in brain functioning or neurological explanation for handedness differentials rather than one based on left-handed children living in a right-handed world.handedness, children, health, cognitive development, family fixed-effects

Detonability of RDX dust in air/oxygen mixtures

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77369/1/AIAA-9528-470.pd

Three divergent lineages within an Australian marsupial ( Petrogale penicillata) suggest multiple major refugia for mesic taxa in southeast Australia

Mesic southeastern Australia represents the continent's ancestral biome and is highly biodiverse, yet its phylogeographic history remains poorly understood. Here, we examine mitochondrial DNA (mtDNA) control region and microsatellite diversity in the brush-tailed rock-wallaby (Petrogale penicillata; n=279 from 31 sites), to assess historic evolutionary and biogeographic processes in southeastern Australia. Our results (mtDNA, microsatellites) confirmed three geographically discrete and genetically divergent lineages within brush-tailed rock-wallabies, whose divergence appears to date to the mid-Pleistocene. These three lineages had been hypothesized previously but data were limited. While the Northern and Central lineages were separated by a known biogeographic barrier (Hunter Valley), the boundary between the Central and Southern lineages was not. We propose that during particularly cool glacial cycles, the high peaks of the Great Dividing Range and the narrow adjacent coastal plain resulted in a more significant north-south barrier for mesic taxa in southeastern Australia than has been previously appreciated. Similarly, located phylogeographic breaks in codistributed species highlight the importance of these regions in shaping the distribution of biodiversity in southeastern Australia and suggest the existence of three major refuge areas during the Pleistocene. Substructuring within the northern lineage also suggests the occurrence of multiple local refugia during some glacial cycles. Within the three major lineages, most brush-tailed rock-wallaby populations were locally highly structured, indicating limited dispersal by both sexes. The three identified lineages represent evolutionarily significant units and should be managed to maximize the retention of genetic diversity within this threatened species

Analysis of Granular Flow in a Pebble-Bed Nuclear Reactor

Pebble-bed nuclear reactor technology, which is currently being revived around the world, raises fundamental questions about dense granular flow in silos. A typical reactor core is composed of graphite fuel pebbles, which drain very slowly in a continuous refueling process. Pebble flow is poorly understood and not easily accessible to experiments, and yet it has a major impact on reactor physics. To address this problem, we perform full-scale, discrete-element simulations in realistic geometries, with up to 440,000 frictional, viscoelastic 6cm-diameter spheres draining in a cylindrical vessel of diameter 3.5m and height 10m with bottom funnels angled at 30 degrees or 60 degrees. We also simulate a bidisperse core with a dynamic central column of smaller graphite moderator pebbles and show that little mixing occurs down to a 1:2 diameter ratio. We analyze the mean velocity, diffusion and mixing, local ordering and porosity (from Voronoi volumes), the residence-time distribution, and the effects of wall friction and discuss implications for reactor design and the basic physics of granular flow.Comment: 18 pages, 21 figure

A decade of ocean changes impacting the ice shelf of Petermann Gletscher, Greenland

Hydrographic data collected during five summer surveys between 2002 and 2015 reveal that the subsurface ocean near Petermann Gletscher, Greenland warmed by 0.015 ± 0.013°C yr-1. New 2015 - 2016 mooring data from beneath Petermann Gletscher’s ice shelf imply a continued warming of 0.025 ± 0.013°C yr-1 with a modest seasonal signal. In 2015 we measured ocean temperatures of 0.28°C near the grounding line of Petermann Gletscher’s ice shelf, which drove submarine melting along the base of the glacier. The resultant meltwater contributed to ocean stratification, which forced a stronger geostrophic circulation at the ice shelf terminus compared with previous years. This increased both the freshwater flux away from the sub-ice shelf cavity and the heat flux into it. Net summertime geostrophic heat flux estimates into the sub-ice shelf cavity exceed the requirement for steady-state melting of Petermann Gletscher’s ice shelf. Likewise, freshwater fluxes away from the glacier exceed the expected steady-state meltwater discharge. These results suggest that the warmer, more active ocean surrounding Petermann Gletscher forces “non steady-state” melting of its ice shelf. When sustained, such melting thins the ice shelf

Developmental Regulation of an Adhesin Gene during Cellular Morphogenesis in the Fungal Pathogen Candida albicans

Peer reviewedPublisher PD