On the classification of quasi-homogeneous curves

We apply techniques of Holomorphic Foliations in the description of the analytic invariants associated to germs of quasi-homogeneous curves in $(\mathbb{C}^2,0)$. As a consequence we obtain an effective method to determine whether two quasi-homogeneous curves are analytically equivalent.Comment: 9 pages, 5 figure

Incomplete Regulation, Asymmetric Information and Collusion-Proofness

In an incomplete regulation framework the Regulator cannot replicate all the possible outcomes by himself since he has no influence on some firms present in the market. When facing asymmetric information regarding the regulated firm’s costs, it may be better for the Regulator to allow the other competitors to extract a truthful report from her through side-payments in a collusion and therefore the “Collusion-Proofness Principle” may not hold. In fact, by introducing an exogenous number of unregulated competitors, Social Welfare differences seem to favour a Collusion-Allowing equilibrium. However, such result will strongly depend on the relative importance given by the Regulator to the Consumer Surplus.Incomplete Regulation, Asymmetric Information, Collusion, Market Competition

Morphological characterization of a polymeric microfiltration membrane by synchrotron radiation computed microtomography

Most commercial polymeric membranes are prepared by phase inversion. The performance of the membranes depends greatly on the morphology of the porous structure formed during the different steps of this process. Researchers in this field have found it extremely difficult to foresee how a change in the composition of the polymer solution will affect pore formation without a set of methods designed to yield detailed knowledge of the morphological structure. This paper reports the new potential associated with X-Ray synchrotron microtomography to characterize the 3D structure of a PvDF hollow fibre microfiltration membrane prepared by phase inversion. 3D morphological data obtained from the ID19 line at the ESRF are presented. The membrane actually appears as a complex three-dimensional bi-continuum of interconnected pores. Within the hollow fibre structure, different regions with various thicknesses and pore size distributions have been identified and well characterized. Transversal views show the anisotropic finger-like structure of pores, while longitudinal sections reveal a honeycomb structure which resembles the structure of highly concentrated water in oil emulsion or dispersion. This typical structure might be obtained during the phase inversion process. How the phase inversion process may result in these morphologies is finally discussed

New Proposals on Portuguese Vegetation (II)

As a consequence of the geobotanical studies that have been developed in west and southern areas of the Iberian Peninsula, four new phytosociological associations are proposed, integrated in the perennial mesophytic grasslands of Stipo giganteae-Agrostietea castellanae (Serratulo flavescentis-Celticetum giganteae, Armerio macrophyllae-Celticetum giganteae, Centaureo rothmaleranae-Celticetum giganteae, and Centaureo coutinhoi-Dactyletum lusitanici). For each proposed unit, besides its syntaxonomical fitting, we present its ecological diagnosis and the serial and catenal context, as well as its patrimonial value

Calibration of ultrafiltration membranes against size exclusion chromatography columns

Using the extension of the concept of universal calibration parameter, yielding a relation between the hydrodynamic volume of molecules and the elution volume in sizeexclusionchromatography (SEC), to retention coefficients in ultrafiltration (UF), we propose a direct calibration of UF membranes against chromatography columns. Plotting the retention coefficient by one given UF membrane of a series of probe molecules versus their elution volume in SEC chromatography provides a calibration curve for this membrane. For a wide range of retentions, such calibration can be directly used to predict the retention of any molecule: one only needs to measure its exclusion volume by the SEC column, and read the retention by the calibrated membrane on the calibration curves. The method has been tested with dextran and PEG for the calibration, and milk proteins as test molecules, for three different membranes. The predicted values of the retention are in rather good agreement with those experimentally measured in a UF cell

Economic Growth, Ecological Technology and Public Intervention

Seminal works on growth theory had mainly focused on exogenous technological change, where a certain given path of technological change was considered. At the end of the 1980s, a new growth theory emerged allowing for the endogeneity of technological change, where economic agents can affect the pace of technological change and where technology is essentially interpreted as “knowledge”. The present paper aims to develop a simple endogenous growth model to study the effects of taxation on dirty intensive resources and the effects of subsidies on clean/ecological intensive resources. It also intends to analyse how exogenous environmental quality can affect the development of better quality (environmentally cleaner) inputs to production. For that, a dynamic general equilibrium growth model is considered based on the endogenous skill-biased technological change literature. It is shown that final-good sector bias is caused by the technological-knowledge bias, which is promoted by government intervention.economic growth, technological change, environment

A regra e o sistema na estrutura da construção de espaço no desenho

O desenho é uma expressão cuja liberdade de pensamento e acção está irrevogavelmente associada à regra e ao sistema, seja como características materiais, ou como estruturas conceptuais. Neste artigo analisam-se diferentes instâncias da regra e do sistema no que constitui a génese e estrutura da construção de espaço no desenho, no quadro da investigação desenvolvida no doutoramento sobre o desenho de espaço, apoiada na prática lectiva enquanto docente de desenho

How a colloidal paste flows – scaling behaviors in dispersions of aggregated particles under mechanical stress –

We have developed a novel computational scheme that allows direct numerical simulation of the mechanical behavior of sticky granular matter under stress. We present here the general method, with particular emphasis on the particle features at the nanometric scale. It is demonstrated that, although sticky granular material is quite complex and is a good example of a challenging computational problem (it is a dynamical problem, with irreversibility, self-organization and dissipation), its main features may be reproduced on the basis of rather simple numerical model, and a small number of physical parameters. This allows precise analysis of the possible deformation processes in soft materials submitted to mechanical stress. This results in direct relationship between the macroscopic rheology of these pastes and local interactions between the particles

Dolarización y desarrollo en la crisis:¿es relevante discutir la soberanía monetaria?

La crisis financiera del 2007-2008 se muestra con contornos constantemente novedosos y desdoblamientos hasta ahora impensados. Se avecinan tiempos aciagos para las economías latinoamericanas. Este artículo parte de la constatación de la marcada continuidad en la gestión monetaria estrictamente ortodoxa y conservadora al interior del vaivén en el ámbito político de América Latina. Nuestro análisis gira en torno al debate sobre la naturaleza de la moneda al interior de algunos exponentes del pensamiento económico heterodoxo y su vínculo con el desarrollo. Resulta de especial interés analítico la experiencia ecuatoriana, porque en ella se conjuga el mantenimiento de la dolarización formal con un gobierno que anheló promover la diversificación de la estructura productiva, como el de Alianza País (AP)

Desglobalización parcial, bancos y América Latina

Texto de divulgación científica publicado en la edición Nº 4 del Boletín "Nuestra América XXI - Desafíos y alternativas", del Grupo de Trabajo Crisis y economía mundial de CLACSO, coordinado por María Josefina Morales y Gabriela Roffinelli