Unit bar architecture in a highly‐variable fluvial discharge regime: Examples from the Burdekin River, Australia

Unit bars are relatively large bedforms that develop in rivers over a wide range of climatic regimes. Unit bars formed within the highly-variable discharge Burdekin River in Queensland, Australia, were examined over three field campaigns between 2015 and 2017. These bars had complex internal structures, dominated by co-sets of cross-stratified and planar-stratified sets. The cross-stratified sets tended to down-climb. The development of complex internal structures was primarily a result of three processes: (i) superimposed bedforms reworking the unit bar avalanche face; (ii) variable discharge triggering reactivation surfaces; and (iii) changes in bar growth direction induced by stage change. Internal structures varied along the length and across the width of unit bars. For the former, down-climbing cross-stratified sets tended to pass into single planar cross-stratified deposits at the downstream end of emergent bars; such variation related to changes in fluvial conditions whilst bars were active. A hierarchy of six categories of fluvial unsteadiness is proposed, with these discussed in relation to their effects on unit bar (and dune) internal structure. Across-deposit variation was caused by changes in superimposed bedform and bar character along bar crests; such changes related to the three-dimensionality of the channel and bar geometry when bars were active. Variation in internal structure is likely to be more pronounced in unit bar deposits than in smaller bedform (for example, dune) deposits formed in the same river. This is because smaller bedforms are more easily washed out or modified by changing discharge conditions and their smaller dimensions restrict the variation in flow conditions that occur over their width. In regimes where unit bar deposits are well-preserved, their architectural variability is a potential aid to their identification. This complex architecture also allows greater resolution in interpreting the conditions before and during bar initiation and development

Informatics approaches to develop dynamic meta-analyses

Peer Reviewe

Influence of energetic-driven “Taylor-Wave” shock-wave prestraining on the structure/property response of depleted uranium

The influence of shock prestraining, via direct energetic “Taylor-wave” (triangular wave) loading, on the post-shock structure/property behavior of depleted uranium (DU) was studied. Samples were shock prestrained within a “soft” shock recovery fixture composed of momemtum traps and a spall plate to assure 1-dimensional loading. The DU samples exhibit roughly a 30% increase in yield strength following shock prestraining to $\sim$45 GPa. The texture evolution in DU was quantified using electron-backscatter diffraction (EBSD). Detailed quantification of the substructure evolution following shock prestraining revealed high volume fractions of {130}, `{172}', and {112} deformation twins. The volume fraction of {130} twins was found to be $\sim$10x the volume fraction of `{172}' and {112} twins. Details of the twin system activation and volume fraction relative to the local Schmidt factor within grains are presented. The influence of HE-driven shock prestraining on the structure/property response of DU is compared and contrasted to that seen in 304SS and 316SS subjected to “Taylor-wave” shock prestraining

Association of adenovirus 36 infection with adiposity and inflammatory-related markers in children

CONTEXT: Although animal studies suggest that adenovirus 36 (Ad36) infection is linked to obesity and systemic inflammation, human data are scant and equivocal. OBJECTIVE: Associations of Ad36 infection with total body adiposity and inflammatory-related markers were determined in 291 children aged 9-13 years (50% female, 49% black). DESIGN: Fasting blood samples were measured for presence of Ad36-specific antibodies and TNF-α, IL-6, vascular endothelial growth factor (VEGF), and monocyte chemoattractant protein-1 (MCP-1). Fat mass and fat-free soft tissue mass were measured by dual-energy X-ray absorptiometry. RESULTS: The overall prevalence of Ad36 seropositivity [Ad36(+)] was 42%. There was a higher percentage of Ad36(+) children in the highest tertiles of TNF-α and IL-6 compared with their respective middle and lowest tertiles (both P .05). CONCLUSIONS: In children, our data suggest that Ad36(+) may be associated with biomarkers implicated in inflammation but not with greater levels of fat mass