A power law distribution in patients' lengths of stay in hospital

The distribution of patients' lengths of stay in English hospitals is measured by using routinely collected data from 11 years. It is found to be well approximated by a power law distribution spanning over more than 3 decades. To explain this observation, a theoretical resource allocation model is presented. It is based on iterative long-term scheduling of hospital beds, and its main assumption is that future beds are allocated preferentially. This represents a situation where di®erent parts of the health care system compete for resources, with bargaining powers proportional to current resource levels

Eigenvalue distribution of large dilute random matrices

We study the eigenvalue distribution of dilute N3N random matrices HN that in the pure ~undiluted! case describe the Hopfield model. We prove that for the fixed dilution parameter a the normalized counting function ~NCF! of HN converges as N!` to a unique sa(l). We find the moments of this distribution explicitly, analyze the 1/a correction, and study the asymptotic properties of sa(l) for large ulu. We prove that sa(l) converges as a !` to the Wigner semicircle distribution ~SCD!. We show that the SCD is the limit of the NCF of other ensembles of dilute random matrices. This could be regarded as evidence of stability of the SCD to dilution, or more generally, to random modulations of large random matrices

High-pressure/high-temperature synthesis of transition metal oxide perovskites

Perovskite and related Ruddlesden-Popper type transition metal oxides synthesised at high pressures and temperatures during the last decade are reviewed. More than 60 such new materials have been reported since 1995. Important developments have included perovskites with complex cation orderings on A and B sites, multiferroic bismuth-based perovskites, and new manganites showing colossal magnetoresistance (CMR) and charge ordering properties

Mediapolis: an introduction

The organisation of this workshop has been prompted by concerns with the way media so often seem to get left out of writing on cities and urban politics (rather than vice-versa). We agree with Iveson’s (2007) argument that urban and media studies have much more in the way of shared concerns when it comes to politics than is conventionally thought to be the case. As a result, we are hoping this workshop will create an occasion for urban scholars to meet those studying media, to explore what difference it makes to explicitly consider the place of media practices in making a politics of cities, and conversely, to consider what is left out when such practices are relegated to the background. In certain ways, we are suggesting a contemporary return to something like Robert Park’s inclination in relation to cities and media. In his seminal essay on the natural history of the newspaper, for example (Park, 1925), Park exhibits a style which does not generally seem to distinguish between or oppose the urban and the media when studying politics and democracy. This surely has something to do with Park’s own intellectual period, and the absence of established disciplines in media or urban studies. Yet this is also precisely the point of the workshop: an opportunity for engagement and discussion through a similar sort of pre-disciplinary spirit

Luscher Term for k-string Potential from Holographic One Loop Corrections

We perform a systematic analysis of k-strings in the framework of the gauge/gravity correspondence. We discuss the Klebanov-Strassler supergravity background which is known to be dual to a confining supersymmetric gauge theory with chiral symmetry breaking. We obtain the k-string tension in agreement with expectations of field theory. Our main new result is the study of one-loop corrections on the string theoretic side. We explicitly find the frequency spectrum for both the bosons and the fermions for quadratic fluctuations about the classical supergravity solution. Further we use the massless modes to compute 1/L contributions to the one loop corrections to the k-string energy. This corresponds to the Luscher term contribution to the k-string potential on the gauge theoretic side of the correspondence.Comment: 39 pages, 3 figures. New Calculation showing explicit k -> M - k symmetry of Energy utilizing the new figure. Discussion of non-k-dependence of Luscher term at end of last section right before Conclusion. Same version to be published in JHE

Numerical Simulation of Baroclinic Jovian Vortices

We examine the evolution of baroclinic vortices in a time-dependent, nonlinear numerical model of a Jovian atmosphere. The model uses a normal-mode expansion in the vertical, using the barotropic and first two baroclinic modes. Results for the stability of baroclinic vortices on an f plane in the absence of a mean zonal flow are similar to results of Earth vortex models, although the presence of a fluid interior on the Jovian planets shifts the stability boundaries to smaller length scales. The presence of a barotropic mean zonal flow in the interior stabilizes vortices against instability and significantly modifies the finite amplitude form of baroclinic instabilities. The effect of a zonal flow on a form of barotropic instability produces periodic oscillations in the latitude and longitude of the vortex as observed at the level of the cloud tops. This instability may explain some, but not all, observations of longitudinal oscillations of vortices on the outer planets. Oscillations in aspect ratio and orientation of stable vortices in a zonal shear flow are observed in this baroclinic model, as in simpler twodimensional models. Such oscillations are also observed in the atmospheres of Jupiter and Neptune. The meridional propagation and decay of vortices on a β plane is inhibited by the presence of a mean zonal flow. The direction of propagation of a vortex relative to the mean zonal flow depends upon the sign of the meridional potential vorticity gradient; combined with observations of vortex drift rates, this may provide a constraint on model assumption for the flow in the deep interior of the Jovian planets

Proposed reference models for nitrous oxide and methane in the middle atmosphere

Data from the Stratospheric and Mesospheric Sounder (SAMS) on the Nimbus 7 satellite, for the period from Jan. 1979 - Dec. 1981, are used to prepare a reference model for the long-lived trace gases, methane and nitrous oxide, in the stratosphere. The model is presented in tabular form on seventeen pressure surfaces from 20 to 0.1 mb, in 10 degree latitude bins from 50S to 70N, and for each month of the year. The means by which the data quality and interannual variability, and some of the more interesting globally and seasonally variable features of the data are discussed briefly