The compressibility and high pressure structure of diopside from first principles simulation

The structure of diopside (CaMgSi2O6) has been calculated at pressures between 0 and 25 GPa using the planewaves and pseudopotentials approach to density functional theory. After applying a pressure correction of 4.66 GPa to allow for the under-binding usually associated with the generalized gradient approximation, cell parameters are in good agreement with experiment. Fitting to the third-order Birch-Murnaghan equation of state yields values of 122 GPa and 4.7 for the bulk modulus and its pressure derivative. In addition to cell parameters, our calculations provide all atomic positional parameters to pressures considerably beyond those currently available from experiment. We have analyzed these data in terms of polyhedral rigidity and regularity and find that the most compressible Ca polyhedron becomes markedly less anisotropic above 10 GPa

Nucleotides: Structure and Properties

Nucleotides consist of a nitrogen-containing base, a five-carbon sugar, and one or more phosphate groups. Cells contain many types of nucleotides, which play a central role in a wide variety of cellular processes, including metabolic regulation and the storage and utilization of genetic information

Still in Deficit: Rights, Regulation, and Democracy in the European Union

Critics of the EU's democratic deficit standardly attribute the problem to either sociocultural reasons, principally the lack of a demos and public sphere, or institutional factors, notably the lack of electoral accountability because of the limited ability of the European Parliament to legislate and control the executive powers of the Commission and the Council of Ministers. Recently two groups of theorists have argued neither deficit need prove problematic. The first group adopts a rights-based view of democracy and claims that a European consensus on rights, as represented by the Charter of Fundamental European Rights, can offer the basis of citizen allegiance to EU wide democracy, thereby overcoming the demos deficit. The second group adopts a public-interest view of democracy and argues that so long as delegated authorities enact policies that are ‘for’ the people, then the absence of institutional forms that facilitate democracy ‘by’ the people are likewise unnecessary—indeed, in certain areas they may be positively harmful. This article argues that both views are normatively and empirically flawed. This is because there is no consensus on rights or the public interest apart from the majority view of a demos secured through parliamentary institutions. To the extent that these remain absent at the EU level, a democratic deficit continues to exist

Understanding self and other

Interpersonal understanding is rooted in social engagement. The question is: How? What features of intersubjective coordination are essential for the growth of concepts about the mind, and how does development proceed on this basis? Carpendale & Lewis (C&L) offer many telling insights, but their account begs questions about the earliest forms of self-other linkage and differentiation, especially as mediated by processes of identification

Energetics of jets from X-ray binaries

I discuss the energetics of synchrotron-emitting outflows, increasingly found to be present in many different classes of X-ray binary systems. It is shown that the outflow is likely to be comparable in power to the integrated X-ray luminosity, traditionally taken to be an indicator of the global mass-transfer rate. This is especially found to be the case in the (low/)hard states of black hole candidate systems. I conclude that jets are extremely important, energetically and dynamically, for the accretion process in the majority of known X-ray binary systems.Comment: To be published in `Proceedings of the Third Microquasar Workshop: Granada Workshop on galactic relativistic jet sources', Eds A. J. Castro-Tirado, J. Greiner and J. M. Paredes, Astrophysics and Space Science, in pres

Spatial variability of groundwater recharge - II. Factors affecting variability and taking account of it in estimating recharge

The accompanying paper provided evidence to suggest that spatial variability of groundwater recharge is ‘true’ variability. This paper attempts to determine the major causes of such variability even at small distances, if there appear to be a frequency distribution to this spatial variability and lastly if it is possible take this variability into account in estimating recharge in an area. The clay content of the top soil appear to have a significant effect on recharge. The spatial variability of recharge appear to be log normally distributed and a way is shown where simple statistics can be used to take account of the spatial variability in estimating recharge

Spatial variability of groundwater recharge - I. Is it really variable?

The spatial variability of recharge is an important consideration in estimating recharge especially as all methods of estimating it are 'point' estimates and in most places recharge varies in space. This paper along with the accompanying paper attempts to find a suitable answer to the question of taking this variability into account in estimating groundwater recharge. This paper attempts to determine if recharge is actually varying in space and that this is 'true' variability and that it is not an artefact of the method used for estimating recharge. It also pulls together information on spatial variability of recharge reported by various workers in the literature, in order to determine if recharge is truly variable in space