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In situ measurements and ship-based resuspension experiments using annular flumes are used to determine sediment stability and critical erosion thresholds for four sites with significantly different sediment characteristics, located in the Celtic Sea at water depths of 100 m. Seasonal and spatial variability of sediment characteristics and erodability is examined, and found to be the result of changes in percentage of organic carbon in the surface sediments (R2 = 0.82) and bulk density (R2 = 0.73) respectively when individual characteristic bed parameters are considered. Principal component analysis and linear regression analysis are used to determine a predictive model for erosion threshold in the Celtic Sea (R2 = 0.99), based on grain size, sorting, kurtosis, bulk density, porosity, percentage fines, organic carbon content and chlorophyll a concentration. Physical sediment characteristics were found to be more significant controls of bed stability than biological factors. Local hydrodynamic conditions are used to determine the likelihood and frequency of resuspension given these critical erosion thresholds. Resuspension is driven by tidal currents, and is common year-round, leading to a constant re-working of bed sediments in particular at the muddier sites. This is confirmed by in situ measurements of suspended sediment concentration. • Bed erodibility in the Celtic Sea a function of organic carbon and bulk density. • Predicting erosion threshold requires emphasis on physical sediment characteristics. • Bed sediments re-worked year round by tidal resuspension, enhanced by winter waves. [ABSTRACT FROM AUTHOR]

Abstract: The electrodeposition of Bi from acidic nitrate solution was examined. Bismuth deposition was determined to be quasi-reversible on Au, with a current efficiency of 100%, based on integration of deposition and stripping voltammetric waves. No interference from nitrate reduction was found on Bi and Au, whereas nitrate reduction occurred on W and Cu electrodes. Analysis of current-time transients clearly shows nucleation on Au to be instantaneous. Field emission SEM revealed nodular deposits with moderate surface roughness. Nodule size varied from 1 to 5μm depending on deposition potential and deposit thickness. X-ray diffraction (XRD) patterns for all deposits were indexed to rhombohedral bismuth. The deposits showed fairly strong (012) crystallographic texture at high deposition overpotentials. [Copyright &y& Elsevier]

Ripples and small-scale bedforms are ubiquitous in shallow water environments under the combined action of currents and waves. Small scale processes linked to their formation and migration are interconnected with sediment transport at larger scales (e.g. tens of metres to kilometres), both resulting in and being affected by large scale sediment transport and geomorphological evolution. The lower shoreface provides a key link between coasts and continental shelves, but the contribution of ripples and small-scale bedforms to sediment transport in this region has yet to be fully addressed. This work presents a study of sediment dynamic processes on the lower shoreface in the presence of small-scale bedforms. Observations were made during the winter of 2017 on the lower shoreface of Perranporth Beach, which is in the south west of the UK and exposed to Atlantic waves. The analysis of morphological expressions and the variability of ripples under waves, currents and wave-current conditions are assessed. Ripple morphology and associated dynamics are analysed for their potential contribution to the exchange of sediment between the lower and the upper shoreface. In the present study it was observed that even though ripples were evolving depending on the wave-current forcing, little ripple migration was observed due to low wave skewness. The implication is that ripple migration and bedload transport are only a small contribution to onshore sediment transport under low to moderate energy conditions. However, during more energetic conditions, ripples were washed out and the wave skewness increased, resulting in onshore sediment transport under a sheet flow regime. This suggests that ripple formation and migration can have little impact on the cross-shore supply of sediment from the lower shoreface to the upper shoreface and that more energetic wave conditions are required to significantly transport sediment towards the beach. • High-resolution observations on the seabed reveal 2D and 3D wave vortex ripples in a macrotidal sandy lower shoreface. • The morphological ripple transitions provide assessment of sediment transport regime thresholds. • The hypothesis of ross-shore sediment supplied from the lower to the upper shoreface through ripple migration is not supported. [ABSTRACT FROM AUTHOR]

Abstract: High purity bright Sn, Sn–Cu and Sn–Pb layers, 3, 7 and 16μm thick were electrodeposited on phosphor bronze cantilever beams in a rotating disk apparatus. Beam deflection measurements within 15min of plating proved that all electrodeposits had in-plane compressive stress. In several days, the surfaces of the Sn–Cu deposits, which have the highest compressive stress, develop 50μm contorted hillocks and 200μm whiskers, pure Sn deposits develop 20μm compact conical hillocks, and Sn–Pb deposits, which have the lowest compressive stress, remain unchanged. The differences between the initial compressive stresses for each alloy and pure Sn is due to the rapid precipitation of Cu6Sn5 or Pb particles, respectively, within supersaturated Sn grains produced by electrodeposition. Over longer time, analysis of beam deflection measurements indicates that the compressive stress is augmented by the formation of Cu6Sn5 on the bronze/Sn interface, while creep of the electrodeposit tends to decrease the compressive stress. Uniform creep occurs for Sn–Pb because it has an equi-axed grain structure. Localized creep in the form of hillocks and whiskers occurs for Sn and Sn–Cu because both have columnar structures. Compact hillocks form for the Sn deposits because the columnar grain boundaries are mobile. Contorted hillocks and whiskers form for the Sn–Cu deposits because the columnar grain boundary motion is impeded. [Copyright &y& Elsevier]

Hemokinin-1 (HK-1) is a recently described mouse tachykinin peptide whose biological functions are not fully understood. To date, a unique receptor for HK-1 has not been identified. Recent studies suggest HK-1 may have a role in immunological functions, but there has been little characterization of HK-1’s effects in the central nervous system (CNS). In the present studies, we confirm that HK-1 is an endogenous agonist at all of the known tachykinin receptors, and is selective for the NK1 receptor over the NK2 and NK3 subtypes. CHO cells transfected with the human NK1 receptor released intracellular calcium in response to HK-1. In addition, HK-1 competed with substance P (SP) for binding to mouse NK1 and human NK1 receptors. In vivo central administration of HK-1 to gerbils and mice induced foot-tapping and scratching behaviors, respectively, similar to those observed following central administration of SP or the NK1 receptor agonist, GR-73632. Furthermore, these behavioral effects were blocked by the selective NK1 receptor antagonist, MK-869. Finally, a comprehensive expression analysis of HK-1 demonstrated that HK-1 mRNA is much more broadly expressed than previously reported with expression observed in many brain regions. Together these data demonstrate that HK-1 is a functional agonist at NK1 receptors and suggest that HK-1 may function both centrally and peripherally. [Copyright &y& Elsevier]