87 research outputs found

    Are the dimensions of private information more multiple than expected? Information asymmetries in the market of supplementary private health insurance in England

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    Our study reexamines standard econometric approaches for the detection of information asymmetries on insurance markets. We claim that evidence based on a standard framework with 2 equations, which uses potential sources of information asymmetries, should stress the importance of heterogeneity in the parameters. We argue that conclusions derived from this methodology can be misleading if the estimated coefficients in such an `unused characteristics' framework are driven by different parts of the population. We show formally that an individual's expected risk from the perspective of insurance, conditioned on certain characteristics (which are not used for calculating the risk premium), can equal the population's expectation in risk { although such characteristics are both related to risk and insurance probability, which is usually interpreted as an indicator of information asymmetries. We provide empirical evidence on the existence of information asymmetries in the market for supplementary private health insurance in the UK. Overall, we found evidence for advantageous selection into the private risk pool; ie people with lower health risk tend to insure more. The main drivers of this phenomenon seem to be characteristics such as income and wealth. Nevertheless, we also found parameter heterogeneity to be relevant, leading to possible misinterpretation if the standard `unused characteristics' approach is applied

    The decomposition of disease and disability life expectancies in England 1992-2004

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    ISBN 978-1-905752-23-2 www.cass.city.ac.uk "This paper originated in an independent report for the Department of Health. Any opinions expressed in this paper are my/our own and not necessarily those of my/our employer or anyone else I/we have discussed them with. In particular, the views expressed may not necessarily reflect the views or policies of the Department of Health. You must not copy this paper or quote it without my/our permission"

    The Role of Private Finance in Paying for Long Term Care

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    An ageing population and increased longevity means that long term care will become progressively more expensive. In 2009 the Government published a Green Paper on future funding options and a White Paper in 2010. This article considers the role of private finance products under the ‘Partnership’ option. It finds that few households are able to pay for LTC based on income and savings but the number increases if housing assets are included. We show that products can be devised for a range of circumstances, although state support would need to continue. We propose a simplified means testing system based on a combination of income and assets

    Renormalized mean-field t-J model of high-Tc superconductivity: comparison with experiment

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    Using an advanced version of the renormalized mean-field theory (RMFT) for the t-J model, we examine spin-singlet superconducting (SC) state of dx2y2d_{x^2 - y^2}-symmetry. Overall doping dependence of the SC gap magnitude is in good agreement with experimental results for Bi2Sr2CaCu2O8+δ\text{Bi}_{2}\text{Sr}_{2}\text{Ca} \text{Cu}_2 \text{O}_{8 + \delta} (BSCCO) and La2xSrxCuO4\text{La}_{2-x}\text{Sr}_{x}\text{Cu} \text{O}_{4} (LSCO) compounds at the optimal doping and in the overdoped regime. We also calculate the dispersion relation for the Bogoliubov quasiparticles and compare our findings both with the angle resolved photoemission data for the cuprates, as well as with the variational Monte Carlo and other mean-field studies. Within the method proposed by Fukushima [cf. Phys. Rev. B \textbf{78}, 115105 (2008)], we analyze different forms of the t-J Hamiltonian, i.e. modifications caused by the form of exchange interaction, and by the presence of three-site terms. It is shown that although the former has a small influence, the latter suppresses strongly the superconductivity. We also analyze the temperature dependence of the gap magnitude and compare the results with those of the recently introduced finite-temperature renormalized mean-field theory (TRMFT) of Wang et al. [cf. Phys. Rev. B \textbf{82}, 125105 (2010)].Comment: 7 pages, 6 figures, 2 tables. Submitted to Physical Review

    Anomalous impurity effects in nonadiabatic superconductors

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    We show that, in contrast with the usual electron-phonon Migdal-Eliashberg theory, the critical temperature Tc of an isotropic s-wave nonadiabatic superconductor is strongly reduced by the presence of diluted non-magnetic impurities. Our results suggest that the recently observed Tc-suppression driven by disorder in K3C60 [Phys. Rev. B vol.55, 3866 (1997)] and in Nd(2-x)CexCuO(4-delta) [Phys. Rev. B vol.58, 8800 (1998)] could be explained in terms of a nonadiabatic electron-phonon coupling. Moreover, we predict that the isotope effect on Tc has an impurity dependence qualitatively different from the one expected for anisotropic superconductors.Comment: 10 pages, euromacr.tex, europhys.sty, 6 figures. Replaced with accepted version (Europhysics Letters

    Zeeman response of d-wave superconductors: Born approximation for impurity and spin-orbit scattering potentials

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    The effects of impurity and spin-orbit scattering potentials can strongly affect the Zeeman response of a d-wave superconductor. Here, both the phase diagram and the quasiparticle density of states are calculated within the Born approximation and it is found that the spin-orbit interaction influences in a qualitatively different way the Zeeman response of d-wave and s-wave superconductors.Comment: 19 pages, 6 eps figures, submitted to Physica

    Gapped optical excitations from gapless phases: imperfect nesting in unconventional density waves

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    We consider the effect of imperfect nesting in quasi-one-dimensional unconventional density waves in the case, when the imperfect nesting and the gap depends on the same wavevector component. The phase diagram is very similar to that in a conventional density wave. The density of states is highly asymmetric with respect to the Fermi energy. The optical conductivity at T=0 remains unchanged for small deviations from perfect nesting. For higher imperfect nesting parameter, an optical gap opens, and considerable amount of spectral weight is transferred to higher frequencies. This makes the optical response of our system very similar to that of a conventional density wave. Qualitatively similar results are expected in d-density waves.Comment: 8 pages, 7 figure
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