27,246 research outputs found
Generalised Calogero-Moser models and universal Lax pair operators
Calogero-Moser models can be generalised for all of the finite reflection
groups. These include models based on non-crystallographic root systems, that
is the root systems of the finite reflection groups, H_3, H_4, and the dihedral
group I_2(m), besides the well-known ones based on crystallographic root
systems, namely those associated with Lie algebras. Universal Lax pair
operators for all of the generalised Calogero-Moser models and for any choices
of the potentials are constructed as linear combinations of the reflection
operators. The consistency conditions are reduced to functional equations for
the coefficient functions of the reflection operators in the Lax pair. There
are only four types of such functional equations corresponding to the
two-dimensional sub-root systems, A_2, B_2, G_2, and I_2(m). The root type and
the minimal type Lax pairs, derived in our previous papers, are given as the
simplest representations. The spectral parameter dependence plays an important
role in the Lax pair operators, which bear a strong resemblance to the Dunkl
operators, a powerful tool for solving quantum Calogero-Moser models.Comment: 37 pages, LaTeX2e, no macro, no figur
Establishing the potential for using routine data on Incapacity Benefit to assess the local impact of policy initiatives
<i>Background</i>: Incapacity Benefit (IB) is the key contributory benefit for people who are incapable of work because of illness or disability.
<i>Methods</i>: The aims were to establish the utility of routinely collected data for local evaluation and to provide a descriptive epidemiology of the IB population in Glasgow and Scotland for the period 2000ā05 using data supplied by the Department for Work and Pensions.
<i>Results</i>: Glasgow's IB population is large in absolute and relative terms but is now falling, mainly due to a decrease in on flow. Claimants, tend to be older, have a poor work history and suffer from mental health problems. The rate of decline has been greater in Glasgow than Scotland, although the rate of on flow is still higher.
<i>Conclusions</i>: Department for Work and Pensions (DWP) data can be used locally to provide important insights into the dynamics of the IB population. However, to be truly useful, more work needs to be undertaken to combine the DWP data with other information
A new code for parameter estimation in searches for gravitational waves from known pulsars
We describe the consistency testing of a new code for gravitational wave
signal parameter estimation in known pulsar searches. The code uses an
implementation of nested sampling to explore the likelihood volume. Using fake
signals and simulated noise we compare this to a previous code that calculated
the signal parameter posterior distributions on both a grid and using a crude
Markov chain Monte Carlo (MCMC) method. We define a new parameterisation of two
orientation angles of neutron stars used in the signal model (the initial phase
and polarisation angle), which breaks a degeneracy between them and allows more
efficient exploration of those parameters. Finally, we briefly describe
potential areas for further study and the uses of this code in the future.Comment: Accepted for proceedings of Amaldi 9 meetin
Introduction: culture mangling: conflict and dissonance in modern language studies
Introduction to the Culture Mangle volume. Locates the essays in the context of divergences and differences of preoccupation in cultural studies as practiced in the different areas of modern language studies in the UK and US. To this end the piece explores tensions and fault lines in constructions of territory, history and identity in various language area disciplines within modern language studies, concentrating notably on Aleksander Sokurovās Russian Ark (2002), a lavish vision of the Hermitage museumās reflective condensation of conflicting and desiring visions and articulations of cultural memory
Comparison of methods for estimating continuous distributions of relaxation times
The nonparametric estimation of the distribution of relaxation times approach
is not as frequently used in the analysis of dispersed response of dielectric
or conductive materials as are other immittance data analysis methods based on
parametric curve fitting techniques. Nevertheless, such distributions can yield
important information about the physical processes present in measured
material. In this letter, we apply two quite different numerical inversion
methods to estimate the distribution of relaxation times for glassy \lila\
dielectric frequency-response data at 225 \kelvin. Both methods yield unique
distributions that agree very closely with the actual exact one accurately
calculated from the corrected bulk-dispersion Kohlrausch model established
independently by means of parametric data fit using the corrected modulus
formalism method. The obtained distributions are also greatly superior to those
estimated using approximate functions equations given in the literature.Comment: 4 pages and 4 figure
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