Informal sector, productivity, and tax collection

The informal sector is a prominent characteristic of many developing countries. Most of the literature has focused on understanding the determinants of informality. The connection between the informal sector and economic development is, nonetheless, relatively less understood. One of the most important determinants of informality is the tax enforcement quality of a country which, some authors argue, additionally distorts firms' decisions and creates inefficiency. In this paper, I assess the quantitative importance of the effects of incomplete tax enforcement on aggregate output and productivity. I use a dynamic general equilibrium framework to study effects that have received little attention in the literature. I calibrate the model using data for Mexico, an economy where 31% of the employees work in informal establishments. I then investigate the effects of improving enforcement. My main finding is that under complete enforcement, Mexico's labor productivity and output would be 17% higher.Informal Sector, Productivity, tax enforcement, TFP, Heterogeneous plants

BV analysis for covariant and non-covariant actions

The equivalence between the covariant and the non-covariant version of a constrained system is shown to hold after quantization in the framework of the field-antifield formalism. Our study covers the cases of Electromagnetism and Yang-Mills fields and sheds light on some aspects of the Faddeev-Popov method, for both the coratiant and non-covariant approaches, which had not been fully clarified in the literature.Comment: 21 pages, preprint # UTTG-02-93, UB-ECM-PF 93/5. To appear in Phys. Rev.

Regularized Green's Function for the Inverse Square Potential

A Green's function approach is presented for the D-dimensional inverse square potential in quantum mechanics. This approach is implemented by the introduction of hyperspherical coordinates and the use of a real-space regulator in the regularized version of the model. The application of Sturm-Liouville theory yields a closed expression for the radial energy Green's function. Finally, the equivalence with a recent path-integral treatment of the same problem is explicitly shown.Comment: 10 pages. The final section was expande

Nociones básicas para la determinación del sexo y la edad en restos bioantropológicos

En muchas ocasiones los/as arqueólogos/as se topan con restos humanos durante las labores de excavación. La necesidad de un primer análisis del material, en muchos casos como consecuencia del mal estado de conservación, hace necesario el conocimiento de unas mínimas nociones de los métodos más útiles para la estimación de la edad y el sexo en restos esqueléticos. Sin embargo, la escasa formación del arqueólogo/a en temas relacionados con la Antropología Física y la dispersión bibliográfica al respecto, hace necesario un conocimiento mínimo de los principales métodos para llevar a cabo esta labor. En este sentido, se presenta en este trabajo una guía básica, aunque apoyada en una amplia bibliografía, que permite un primer acercamiento a este tipo de estudios, contribuyéndose así a la formación interdisciplinar de los/las arqueólogos/as.Many times during excavations archaeologists have to deal with human remains. Their preservation as well as other circumstances can lead to the necessity of making the first anthropological analysis in the field. The problem is that most of the archaeologists don't have the anthropological knowledge necessary to do this. Besides that, the bibliography about the subject tends to be much dispersed. This work is a basic guide, supported on a wide bibliography, which intends to help archaeologists to perform preliminary bioanthropological studies

NN Scattering: Chiral Predictions for Asymptotic Observables

We assume that the nuclear potential for distances larger than 2.5 fm is given just by the exchanges of one and two pions and, for the latter, we adopt a model based on chiral symmetry and subthreshold pion-nucleon amplitudes, which contains no free parameters. The predictions produced by this model for nucleon-nucleon observables are calculated and shown to agree well with both experiment and those due to phenomenological potentials.Comment: 16 pages, 12 PS figures included, to appear in Physical Review

SIMANFOR: Una aplicación web para simular alternativas de gestión forestal sostenible

Growth and yield models at different scales are useful tools for forest stakeholders. Adequate simulation of forest stand conditions after different silvicultural scenarios allows stakeholders to adopt appropriate actions to maintain forest integrity while forest products and services are obtained to benefit society as a whole. SIMANFOR is a platform to simulate sustainable forest management alternatives, integrating different modules to manage forest inventories, simulate and project stand conditions and maintain systems security and integrity. SIMANFOR output is compatible with an Office environment (Microsoft or Open), allowing users to exchange data and files between SIMANFOR and their own software. New developments are being planned under a web 2.0 environment to take advantage of user input to improve SIMANFOR in the future.Los modelos forestales de crecimiento y producción a diferentes escalas son herramientas útiles para los responsables de la toma de decisiones. La simulación adecuada de las condiciones de los rodales forestales tras diferentes escenarios selvícolas permite a estos responsables adoptar decisiones apropiadas para mantener la integridad de los ecosistemas forestales al tiempo que se obtienen bienes y servicios para el beneficio de la sociedad en su conjunto. SIMANFOR es una plataforma para simular alternativas de gestión forestal sostenible que integra diferentes módulos para gestionar inventarios forestales, simular y proyectar las características de los rodales y mantener la integridad de los ecosistemas. Las salidas de SIMANFOR son compatibles tanto con Microsoft como con Open Office, lo que permite a los usuarios intercambiar datos y documentos entre SIMANFOR y su propio software. Nuevos desarrollos están siendo implementados bajo la filosofía web 2.0 para aprovechar la información de los usuarios y así mejorar SIMANFOR en el futuro

Statistical Mechanics of finite arrays of coupled bistable elements

We discuss the equilibrium of a single collective variable characterizing a finite set of coupled, noisy, bistable systems as the noise strength, the size and the coupling parameter are varied. We identify distinct regions in parameter space. The results obtained in prior works in the asymptotic infinite size limit are significantly different from the finite size results. A procedure to construct approximate 1-dimensional Langevin equation is adopted. This equation provides a useful tool to understand the collective behavior even in the presence of an external driving force

Three-pion exchange: a gap in the nucleon-nucleon potential

The leading contribution to the three-pion exchange nucleon-nucleon potential is calculated in the framework of chiral symmetry. It has pseudoscalar and axial components and is dominated by the former, which has a range of about 1.5 fm and tends to enhance the OPEP. The strength of this force does not depend on the pion mass and hence it survives in the chiral limit.Comment: 20 pages, 5 figures, 1 tabl

ESC NN-Potentials in Momentum Space. II. Meson-Pair Exchange Potentials

The partial wave projection of the Nijmegen soft-core potential model for Meson-Pair-Exchange (MPE) for NN-scattering in momentum space is presented. Here, nucleon-nucleon momentum space MPE-potentials are NN-interactions where either one or both nucleons contains a meson-pair vertex. Dynamically, the meson-pair vertices can be viewed as describing in an effective way (part of) the effects of heavy-meson exchange and meson-nucleon resonances. From the point of view of ``duality,'' these two kinds of contribution are roughly equivalent. Part of the MPE-vertices can be found in the chiral-invariant phenomenological Lagrangians that have a basis in spontaneous broken chiral symmetry. It is shown that the MPE-interactions are a very important component of the nuclear force, which indeed enables a very succesful description of the low and medium energy NN-data. Here we present a precise fit to the NN-data with the extended-soft-core (ESC) model containing OBE-, PS-PS-, and MPE-potentials. An excellent description of the NN-data for $T_{Lab} \leq 350$ MeV is presented and discussed. Phase shifts are given and a $\chi^2_{p.d.p.} = 1.15$ is reached.Comment: 27 pages, 5 PostScript figures, revtex