Quasiperiodic oscillations in a strong gravitational field around neutron stars testing braneworld models

The strong gravitational field of neutron stars in the brany universe could be described by spherically symmetric solutions with a metric in the exterior to the brany stars being of the Reissner-Nordstrom type containing a brany tidal charge representing the tidal effect of the bulk spacetime onto the star structure. We investigate the role of the tidal charge in orbital models of high-frequency quasiperiodic oscillations (QPOs) observed in neutron star binary systems. We focus on the relativistic precession model. We give the radial profiles of frequencies of the Keplerian (vertical) and radial epicyclic oscillations. We show how the standard relativistic precession model modified by the tidal charge fits the observational data, giving estimates of the allowed values of the tidal charge and the brane tension based on the processes going in the vicinity of neutron stars. We compare the strong field regime restrictions with those given in the weak-field limit of solar system experiments.Comment: 26 pages, 6 figure

And the first shall be the last

This study analyzes the puzzle of Hungarian economic drifting in a long run perspective. The underlying puzzle for the investigation is why bad policies are invariably popular and good policies unpopular, thus why political and economic rationality never overlap. The first part of the article summarizes in eight points the basic features of the postwar period. Then six lessons are offered, which might be useful for other countries in transition or for students of comparative economics and politics, lessons that can be generalized on the basis of the individual country experience

European studies: Taking stock and looking ahead

This essay is an attempt to generalize experiences of Central and Eastern European universities in the field of European Studies over the past 20 years. The paper follows the logic of business analysis in order to come up with proposals for future action