On the gravitomagnetic effects in cylindrically symmetric spacetimes

Using gyroscopes we generalize results, obtained for the gravitomagnetic clock effect in the particular case when the exterior spacetime is produced by a rotating dust cylinder, to the case when the vacuum spacetime is described by the general cylindrically symmetric Lewis spacetime. Results are contrasted with those obtained for the Kerr spacetime.Comment: 11 pages Latex, to appear in J.Math.Phy

Shear-free and homology conditions for self-gravitating dissipative fluids

The shear free condition is studied for dissipative relativistic self-gravitating fluids in the quasi-static approximation. It is shown that, in the Newtonian limit, such condition implies the linear homology law for the velocity of a fluid element, only if homology conditions are further imposed on the temperature and the emission rate. It is also shown that the shear-free plus the homogeneous expansion rate conditions are equivalent (in the Newtonian limit) to the homology conditions. Deviations from homology and their prospective applications to some astrophysical scenarios are discussed, and a model is worked out.Comment: 13 pages Latex. To apppear in Month.Not.Roy.Astr.Soc. Corrected typo

Cylindrical Collapse and Gravitational Waves

We study the matching conditions for a collapsing anisotropic cylindrical perfect fluid, and we show that its radial pressure is non zero on the surface of the cylinder and proportional to the time dependent part of the field produced by the collapsing fluid. This result resembles the one that arises for the radiation - though non-gravitational - in the spherically symmetric collapsing dissipative fluid, in the diffusion approximation.Comment: Some comments and a new reference added. To appear in Class. Quantum. Gra

Geodesics in Lewis Spacetime

The geodesic equations are integrated for the Lewis metric and the effects of the different parameters appearing in the Weyl class on the motion of test particles are brought out. Particular attention deserves the appearance of a force parallel to the axial axis and without Newtonian analogue.Comment: 15 pages, Late

Dedollarization, Indexation and Nominalization: The Chilean Experience

This paper revisits the Chilean experience with dollarization, indexation and nominalization in the 1958-2003 period. The purpose is to understand how Chile generally avoided dollarization and actually dedollarized in the 80s in order to draw some lessons for other countries. We find that many policies that Chile pursued are not easy to implement elsewhere. Some key characteristics of the Chilean process are related to initial institutional conditions and developments, whereas others are connected to macroeconomic performance and specific regulations. Indexation plays a key role in explaining how dollarization can be avoided.

The Levi-Civita spacetime as a limiting case of the Gamma spacetime

It is shown that the Levi-Civita metric can be obtained from a family of the Weyl metric, the Gamma metric, by taking the limit when the length of its Newtonian image source tends to infinity. In this process a relationship appears between two fundamental parameters of both metrics.Comment: LaTeX2e 17 page

Matrix Ernst Potentials and Orthogonal Symmetry for Heterotic String in Three Dimensions

A new matrix representation for low-energy limit of heterotic string theory reduced to three dimensions is considered. The pair of matrix Ernst Potentials uniquely connected with the coset matrix is derived. The action of the symmetry group on the Ernst potentials is established.Comment: 10 pages in LaTe