Fe alloy slurry and a compacting cumulate pile across Earth's inner-core boundary

Seismic observations show a reduced compressional-wave gradient at the base of the outer core relative to the preliminary reference Earth model and seismic wave asymmetry between the east-west hemispheres at the top of the inner core. Here, we propose a model for the inner core boundary (ICB), where a slurry layer forms through fractional crystallization of an Fe alloy at the base of the outer core (F layer) above a compacting cumulate pile at the top of the inner core (F' layer). Using recent mineral physics data, we show that fractional crystallization of an Fe alloy (e.g., Fe-Si-O) with light element partitioning can explain the observed reduced velocity gradient in the F layer, in cases with a solid fraction of ~15(5)% in liquid with a compositional gradient due to preferential light element partitioning into liquid. The compacting cumulate pile in the F' layer may exhibit lateral variations in thickness between the east-west hemispheres due to lateral variations of large-scale heat flow in the outer core, which may explain the east-west asymmetry observed in the seismic velocity. Our interpretations suggest that the inner core with solid Fe alloy has a high shear viscosity of ~10^23 Pa s.Comment: v2, 39 pages with 10 figure

Microbiome acquisition during larval settlement of the barnacle Semibalanus balanoides

Barnacles are conspicuous members of rocky intertidal communities and settlement of the final larval stage, the cyprid, is influenced by the presence of biofilms. While modulation of cyprid settlement by biofilms has been studied extensively, the acquisition of a specific microbiome by the settling larva has not. This study investigated settlement in the field of Semibalanus balanoides in two consecutive years when the composition of the benthic bacterial community differed. In both years, settling cyprids adopted a specific sub-set of benthic bacteria that was distinct from the planktonic cyprid and the benthos. This microbiome was consistent, regardless of annual variability in the benthic community structure, and established within hours of settlement. The results imply that a natural process of selection occurs during the critical final transition of S. balanoides to the sessile form. The apparent consistency of this process between years suggests that optimal growth and survival of barnacles could depend upon a complex inter-kingdom relationship, as has been demonstrated in other animal systems

The economic performance of the New England states in 2004: an overview

The year 2004 marked the beginning of New England’s economic turnaround. After three consecutive years of job losses — not to mention 86 years of World Series famine — the region emerged victorious. All six New England states added jobs over the course of the year and experienced reductions in unemployment. Job growth in the region, however, was sluggish compared with the nation overall. Recovery was also reflected in strong exports growth, increases in the economic activity index, and improved consumer confidence. Although consumer price inflation in New England was milder than in recent years, home prices continued to escalate at above-average rates.Economic conditions - New England

The Politics of Service Delivery Reform

This article identifies the leaders, the supporters and the resisters of public service reform. It adopts a principal–agent framework, comparing reality with an ‘ideal’ situation in which citizens are the principals over political policy-makers as their agents, and policy-makers are the principals over public service officials as their agents. Reform in most developing countries is complicated by an additional set of external actors — international financial institutions and donors. In practice, international agencies and core government officials usually act as the ‘principals’ in the determination of reforms. The analysis identifies the interests involved in reform, indicating how the balance between them is affected by institutional and sectoral factors. Organizational reforms, particularly in the social sectors, present greater difficulties than first generation economic policy reforms

The Evolution of Private Equity: Corporate Restructuring in the UK, c.1945-2010

The paper analyses the role of private equity in restructuring the UK corporate economy. It develops a theoretical synthesis to show that the evolution of the PE industry and firms in which it invested were governed by the relations of corporate governance between investor and investee companies. Effective governance relations were a necessary condition for success and complement firm specific resources to create competitive advantage. Four case studies are used to show the contrasting effects of these determining factors, ICFC and Slater Walker, and the two waves of buy-out centred restructuring that developed with the maturity of the PE industry after 1980. In contrast to the evolutionary approach, the periodisations utilised in this study show that structural breaks associated with points of institutional reform are also necessary to make firm specific resource and governance determinants of competitive advantage operable