Modelling the lava dome extruded at Soufrière Hills Volcano, Montserrat, August 2005–May 2006. Part I: Dome shape and internal structure

Lava domes comprise core, carapace, and clastic talus components. They can grow endogenously by inflation of a core and/or exogenously with the extrusion of shear bounded lobes and whaleback lobes at the surface. Internal structure is paramount in determining the extent to which lava dome growth evolves stably, or conversely the propensity for collapse. The more core lava that exists within a dome, in both relative and absolute terms, the more explosive energy is available, both for large pyroclastic flows following collapse and in particular for lateral blast events following very rapid removal of lateral support to the dome. Knowledge of the location of the core lava within the dome is also relevant for hazard assessment purposes. A spreading toe, or lobe of core lava, over a talus substrate may be both relatively unstable and likely to accelerate to more violent activity during the early phases of a retrogressive collapse. Soufrière Hills Volcano, Montserrat has been erupting since 1995 and has produced numerous lava domes that have undergone repeated collapse events. We consider one continuous dome growth period, from August 2005 to May 2006 that resulted in a dome collapse event on 20th May 2006. The collapse event lasted 3 h, removing the whole dome plus dome remnants from a previous growth period in an unusually violent and rapid collapse event. We use an axisymmetrical computational Finite Element Method model for the growth and evolution of a lava dome. Our model comprises evolving core, carapace and talus components based on axisymmetrical endogenous dome growth, which permits us to model the interface between talus and core. Despite explicitly only modelling axisymmetrical endogenous dome growth our core–talus model simulates many of the observed growth characteristics of the 2005–2006 SHV lava dome well. Further, it is possible for our simulations to replicate large-scale exogenous characteristics when a considerable volume of talus has accumulated around the lower flanks of the dome. Model results suggest that dome core can override talus within a growing dome, potentially generating a region of significant weakness and a potential locus for collapse initiation.

Apolipoprotein E genotype and alpha-tocopherol modulate amyloid precursor protein metabolism and cell cycle regulation

Apolipoprotein E4 (apoE4) genotype is associated with an increased risk for Alzheimer's disease (AD). This is thought to be in part attributable to an impact of apoE genotype on the processing of the transmembrane amyloid precursor protein (APP) thereby contributing to amyloid beta peptide formation in apoE4 carriers, which is a primary patho-physiological feature of AD. As apoE and alphato-copherol (alpha-toc) have been shown to modulate membrane bilayer properties and hippocampal gene expression, we studied the effect of apoE genotype on APP metabolism and cell cycle regulation in response to dietary a-toc. ApoE3 and apoE4 transgenic mice were fed a diet low (VE) or high (+VE) in vitamin E (3 and 235 mg alpha-toe/kg diet, respectively) for 12 weeks. Cholesterol levels and membrane fluidity were not different in synaptosomal plasma membranes isolated from brains of apoE3 and apoE4 mice (-VE and +VE). Non-amyloidogenic alpha-secretase mRNA concentration and activity were significantly higher in brains of apoE3 relative to apoE4 mice irrespective of the dietary a-toe supply, while amyloidogenic beta-secretase and gamma-secretase remained unchanged. Relative mRNA concentration of cell cycle related proteins were modulated differentially by dietary a-toc supplementation in apoE3 and apoE4 mice, suggesting genotype-dependent signalling effects on cell cycle regulation.

Time of emergence of climate signals

The time at which the signal of climate change emerges from the noise of natural climate variability (Time of Emergence, ToE) is a key variable for climate predictions and risk assessments. Here we present a methodology for estimating ToE for individual climate models, and use it to make maps of ToE for surface air temperature (SAT) based on the CMIP3 global climate models. Consistent with previous studies we show that the median ToE occurs several decades sooner in low latitudes, particularly in boreal summer, than in mid-latitudes. We also show that the median ToE in the Arctic occurs sooner in boreal winter than in boreal summer. A key new aspect of our study is that we quantify the uncertainty in ToE that arises not only from inter-model differences in the magnitude of the climate change signal, but also from large differences in the simulation of natural climate variability. The uncertainty in ToE is at least 30 years in the regions examined, and as much as 60 years in some regions. Alternative emissions scenarios lead to changes in both the median ToE (by a decade or more) and its uncertainty. The SRES B1 scenario is associated with a very large uncertainty in ToE in some regions. Our findings have important implications for climate modelling and climate policy which we discuss.

Investigation into the adoption intention of social CRM in Saudi banks

The growth of Web 2.0 generation will have influence on developing strong relationships with customers. Even though Web 2.0 technologies and applications have gained significant attention recently by academics and practitioners, research into its potential integration with CRM system remains a poorly investigated subject. This paper aims to investigate the adoption intention of social CRM system, focusing on Saudi banks. A conceptual model was proposed based on technology organisation and environment (TOE) framework. A qualitative approach was applied to validate the research model. The finding suggests that technology infrastructure, and competitive pressures tend to be the most influential drivers to adopt social CRM. In contrast, the limited number of IT experts, security concerns, and organisational structure were found to negatively affect social CRM adoption intention.

Changes of the equilibrium line altitude since the Little Ice Age in the Nepalese Himalayas

Changes of the equilibrium-line altitude (ELA) since the end of the Little Ice Age (LIA) in eastern Nepal have been studied using glacier inventory data. The toe-to-headwall altitude ratios (THARs) for individual glaciers were calculated for 1992, and used to estimate the ELA in 1959 and at the end of the LIA. THAR for debris-free glaciers is found to be smaller than for debris-covered glaciers. The ELAs for debris-covered glaciers are higher than those for debris-free glaciers in eastern Nepal. There is considerable variation in the reconstructed change in ELA (ΔELA) between glaciers within specific regions and between regions. This is not related to climate gradients, but results from differences in glacier aspect: southeast- and south-facing glaciers show larger ΔELAs in eastern Nepal than north- or west-facing glaciers. The data suggest that the rate of ELA rise may have accelerated in the last few decades. The limited number of climate records from Nepal, and analyses using a simple ELA–climate model, suggest that the higher rate of the ΔELA between 1959 and 1992 is a result of increased warming that occurred after the 1970s at higher altitudes in Nepal.