Orbitally Excited Baryon Spectroscopy in the 1/Nc Expansion

The discussion of the 70-plet of negative parity baryons illustrates the large Nc QCD approach to orbitally excited baryons. In the case of the l=1 baryons the existing data allows to make numerous predictions to first order in the SU(3) symmetry breaking. New relations between splittings are found that follow from the spin-flavor symmetry breaking. The Lambda(1405) is well described as a three-quark state and a spin-orbit partner of the Lambda(1520). Singlet states with higher orbital angular momentum are briefly discussed.Comment: 10 pages. Invited talk at The Phenomenology of Large Nc QCD, Tempe, Arizona, 9-11 Jan 200

The Implicit Function Theorem for continuous functions

In the present paper we obtain a new homological version of the implicit function theorem and some versions of the Darboux theorem. Such results are proved for continuous maps on topological manifolds. As a consequence, some versions of these classic theorems are proved when we consider differenciable (not necessarily C^1) maps.Comment: 9 pages, no figure

Countercyclical Fiscal Policy, A Review of the Literature, Empirical Evidence and some Policy Proposals

stabilization, fiscal policy, capital flows, taxation

On the Geometric Principles of Surface Growth

We introduce a new equation describing epitaxial growth processes. This equation is derived from a simple variational geometric principle and it has a straightforward interpretation in terms of continuum and microscopic physics. It is also able to reproduce the critical behavior already observed, mound formation and mass conservation, but however does not fit a divergence form as the most commonly spread models of conserved surface growth. This formulation allows us to connect the results of the dynamic renormalization group analysis with intuitive geometric principles, whose generic character may well allow them to describe surface growth and other phenomena in different areas of physics