Welfare Improving Contracts in Cournot Markets

The question this paper addresses is whether a government can regulate a Cournot oligopolist market to give higher level of welfare without changing either the strategic variable (output quantity) or the way prices are determined (by an auctioneer). The problem is set as a two- stage game played by profit-maximizing firms and a welfare-maximizing government. Firms are symmetric in capacity and technology but asymmetric in ownership. The government owns one firm and uses it strategically. The main policy implication of the model is that by owning and controlling one single firm, a government can regulate an entire industry and achieve welfare improvements. This is possible as the decision-making asymmetry among privately and publicly owned firms allows the government to change the context in which the quantity competition takes place. In addition, this paper shows that the social objectives of the government are not incompatible with profit maximization targets. The government improves the \QTR{it}{total }welfare of the economy if and only if it maximizes profits in its own firm. We shall see that, in equilibrium, the publicly-owned firm maximizes profit either by producing the Stackelberg leader output or the competitive output.Cournot competition, Welfare, Contracts

Regulation of T cell responses by Heme Oxygenase-1

Tese de mestrado, Biologia (Biologia Molecular e Genética), 2008, Universidade de Lisboa, Faculdade de CiênciasMultiple sclerosis (MS) is a chronic inflammatory disease that affects the central nervous system (CNS). It is estimated that over 2.5 million people, mainly young adults between 25 and 40 years old, suffer from this disease. MS pathology is characterized by multifocal CNS inflammation, degeneration of the myelin sheath, surrounding the axons of neurons, and formation of sclerotic plaques that leads to axonal damage. The etiology of the disease remains unknown with genetic and environmental factors being important for its development. Mechanisms that lead to CNS degeneration result from a local inflammatory response characterized by the recruitment of T cells that recognize myelin peptides against which they mount an effector response. Heme Oxygenase-1 (HO-1) is a ubiquitously expressed stress-induced enzyme, responsible for the degradation of free heme into iron (Fe), biliverdin (BV) and carbon monoxide (CO). HO-1 controls inflammatory processes such as the ones associated with the development of MS. It is expressed in the CNS during MS as well as in experimental autoimmune encephalomyelitis (EAE), a murine model of MS. Deletion of HO-1 is associated with increased susceptibility to EAE, while pharmacological induction of its expression arrests EAE progression. The protective effect of HO-1 is associated with inhibition of expression of histocompatibility complex class II (MHC class II) on antigen presenting cells (APC), including dendritic cells (DCs). The main hypothesis tested in this project was that expression of HO-1 in DCs might modulate T cell responses in a manner that prevents the progression of EAE. We found that absence of HO-1 in DCs does not affect significantly its maturation by modulating the expression of surface activation markers. However, we failed to demonstrate whether this absence could afford any effect on the disease, when DCs are adoptively transferred into naïve mice, leading to a more severe outcome when compared to Hmox1+/+ DCsResumo alargado em português disponível no document

Remarks on the stability of Cartesian PMLs in corners

This work is a contribution to the understanding of the question of stability of Perfectly Matched Layers (PMLs) in corners, at continuous and discrete levels. First, stability results are presented for the Cartesian PMLs associated to a general first-order hyperbolic system. Then, in the context of the pressure-velocity formulation of the acoustic wave propagation, an unsplit PML formulation is discretized with spectral mixed finite elements in space and finite differences in time. It is shown, through the stability analysis of two different schemes, how a bad choice of the time discretization can deteriorate the CFL stability condition. Some numerical results are finally presented to illustrate these stability results

Elaboration of thin foils in copper and zinc by self-induced ion plating

The aim of this work was to determine the ability to produce thin metallic foils by self-induced ion plating. Foils of pure copper and pure zinc with a thickness of 35 μm have been successfully produced and their characteristics have been compared to foils obtained by conventional techniques (i.e. electroplating and rolling). Results show the following: (i) more or less compact microstructures can be obtained by self-induced ion plating depending on gas pressure and substrate temperature; (ii) microstructures obtained by self-induced ion plating are quite different from those obtained by electroplating and rolling; (iii) Young’s modulus depends on foils roughness; (iv) hardness depends on grain size by exhibiting a Hall-Petch behavior in the case of copper foils and an “inverse” Hall-Petch behavior in the case of zinc foils