44,858 research outputs found
Generalised Fractional Evolution Equations of Caputo Type
This paper is devoted to the study of generalised time-fractional evolution
equations involving Caputo type derivatives. Using analytical methods and
probabilistic arguments we obtain well-posedness results and stochastic
representations for the solutions. These results encompass known linear and
non-linear equations from classical fractional partial differential equations
such as the time-space-fractional diffusion equation, as well as their far
reaching extensions. \\ Meaning is given to a probabilistic generalisation of
Mittag-Leffler functions.Comment: To be published in 'Chaos, Solitons & Fractals
Testing for Adverse Selection into Private Medical Insurance
We develop a test for adverse selection and use it to examine privatehealth insurance markets. In contrast to earlier papers that consider apurely private system or a system in which private insurance supplementsa public system, we focus our attention on a system where privately fundedhealth care is substitutive of the publicly funded one. Using a model ofcompetition among insurers, we generate predictions about the correlationbetween risk and the probability of taking private insurance under bothsymmetric information and adverse selection. These predictions constitutethe basis for our adverse selection test. The theoretical model is also usefulto conclude that the setting that we focus on is especially attractive to testfor adverse selection. Using the British Household Panel Survey, we findevidence that adverse selection is present in this market. We develop a test for adverse selection and use it to examine privatehealth insurance markets. In contrast to earlier papers that consider apurely private system or a system in which private insurance supplementsa public system, we focus our attention on a system where privately fundedhealth care is substitutive of the publicly funded one. Using a model ofcompetition among insurers, we generate predictions about the correlationbetween risk and the probability of taking private insurance under bothsymmetric information and adverse selection. These predictions constitutethe basis for our adverse selection test. The theoretical model is also usefulto conclude that the setting that we focus on is especially attractive to testfor adverse selection. Using the British Household Panel Survey, we find evidence that adverse selection is present in this market
A note on the practical feasibility of domain-wall fermions
Domain-wall fermions preserve chiral symmetry up to terms that decrease
exponentially when the lattice size in the fifth dimension is taken to
infinity. The associated rates of convergence are given by the low-lying
eigenvalues of a simple local operator in four dimensions. These can be
computed using the Ritz functional technique and it turns out that the
convergence tends to be extremely slow in the range of lattice spacings
relevant to large-volume numerical simulations of lattice QCD. Two methods to
improve on this situation are discussed.Comment: 14 pages, talk given by P. H. at the workshop on {\em Current
theoretical problems in lattice field theory}, Ringberg, German
Coherent pion production off nuclei at T2K and MiniBooNE energies revisited
As a result of a new improved fit to old bubble chamber data of the dominant
axial C_5^A nucleon-to-Delta form factor, and due to the relevance of this form
factor for neutrino induced coherent pion production, we re-evaluate our model
predictions in Phys. Rev. D79, 013002 (2009) for different observables of the
latter reaction. Central values for the total cross sections increase by 20% to
30%, while differential cross sections do not change their shape appreciably.
Furthermore, we also compute the uncertainties on total, differential and flux
averaged cross sections induced by the errors in the determination of C_5^A.
Our new results turn out to be compatible within about 1 sigma with the former
ones. Finally, we stress the existing tension between the recent experimental
determination of the sigma(CC coh \pi^+)/sigma(NC coh \pi^0) ratio by the
SciBooNE Collaboration and the theoretical predictions.Comment: 6 latex pages, 1 table, 2 figures. Shortened versio
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