Immigration and Pension Benefits in the Host-country

This paper examines the role that low-skilled immigrant labor force plays in determining the benefits of the public pension of the host population. With an overlapping-generations model in continuous time which allows to identify which groups of native population are better or worse off with immigration and a fully redistributive pension system, we find that the retirement benefits and hence the welfare levels of the host population are affected in a different way whether sharing or not pension benefits with immigrants. In this sense, the youngest local population may prefer, contrary to the oldest ones, a policy of closed borders.Immigration, welfare, pension benefits.

Assessing brand image through communalitites and asymmetries brand-to-attribute and attribute-to-brand associations.

Brand image is a key component of customer-based brand equity, and refers to the associations a consumer holds in memory. Such associations are often directional; one should distinguish between brand-to-attribute and attribute-to-brand associations. Information on these associations arise from two ways of collecting data respectively: brand-by-brand evaluations of all attributes and attribute-by-attribute evaluations of all brands. In this paper, the authors present a methodological approach, namely correspondence analysis of matched matrices, to assess the communalitites as well as asymmetries between brand-to-attribute and attribute-to-brand associations. The methodology results in perceptual maps visualizing brand image. The approach is illustrated in an empirical market research project in which two samples of consumers evaluated ten brands of deodorants and eleven attributes

Defined Contribution vs Defined Pension: Reforming the Legal Retirement Age

In this paper we analyze the effects of changing Social Security parameters on the optimal legal retirement age. Two Social Security Systems are studied, with opposite results. When the pension scheme has a defined contribution, a more redistributive system will delay the preferred legal retirement age. On the other hand, when the pension benefit is the defined parameter, the increase in the redistribution level will lower this preferred age.

Interaction of point sources and vortices for incompressible planar fluids

We consider a new system of differential equations which is at the same time gradient and locally Hamiltonian. It is obtained by just replacing a factor in the equations of interaction for N point vortices, and it is interpreted as an interaction of N point sources. Because of the local Hamiltonian structure and the symmetries it obeys, it does possess some of the first integrals that appear in the N vortex problem. We will show that binary collisions are easily blown up in this case since the equations of motion are of first order. This method may be easily generalized to the blow up of higher order collisions. We then generalize the model further to interactions of sources and vortices.Comment: 9 page

Optical absorption of divalent metal tungstates: Correlation between the band-gap energy and the cation ionic radius

We have carried out optical-absorption and reflectance measurements at room temperature in single crystals of AWO4 tungstates (A = Ba, Ca, Cd, Cu, Pb, Sr, and Zn). From the experimental results their band-gap energy has been determined to be 5.26 eV (BaWO4), 5.08 eV (SrWO4), 4.94 eV (CaWO4), 4.15 eV (CdWO4), 3.9-4.4 eV (ZnWO4), 3.8-4.2 eV (PbWO4), and 2.3 eV (CuWO4). The results are discussed in terms of the electronic structure of the studied tungstates. It has been found that those compounds where only the s electron states of the A2+ cation hybridize with the O 2p and W 5d states (e.g BaWO4) have larger band-gap energies than those where also p, d, and f states of the A2+ cation contribute to the top of the valence band and the bottom of the conduction band (e.g. PbWO4). The results are of importance in view of the large discrepancies existent in prevoiusly published data.Comment: 16 pages, 3 figures, 1 tabl

Non singular Hamiltonian systems and geodesic flows on surfaces with negative curvature

We extend here results for escapes in any given direction of the configuration space of a mechanical system with a non singular bounded at infinity homogeneus potential of degree -1, when the energy is positive. We use geometrical methods for analyzing the parallel and asymptotic escapes of this type of systems. By using Riemannian geometry methods we prove under suitable conditions on the potential that all the orbits escaping in a given direction are asymptotically parallel among themselves. We introduce a conformal Riemannian metric with negative curvature in the interior of the Hill's region for a fixed positive energy level and we consider the boundary as a singular part of the infinity. The associated geodesic flow has as solution curves those of the problem for a fixed energy. We perform the compactification of the region via the limiting directions of the geodesic flow, obtaining a closed unit disk with a quasi-complete metric of negative curvature