International Portfolio Diversification: Short-Term Financial Assets and Gold

Using a continuous-time finance-theoretic framework, this paper presents the optimal portfolio rule of an international investor who consumes N national composite goods and who holds N domestic-currency-denominated assets with known nominal interest rates in an environment where prices of goods, assets and exchange rates follow geometric Brownian motion. It is shown that the currency portfolio rule described in Macedo (1982a) is applicable to the case where there are N assets with a known price and one asset, gold, with a random rice in terms of the numeraire. Under these assumptions, it is found that the optimal portfolio of an investor consuming goods from all major industrialized countries (according to their weight in total trade) would be dominated in March 1981 by long positions in U.S. dollars (25%), yen (17%), D. marks (16%), French francs (15%) and pounds sterling (10%). An investor consuming only U.S. goods, by contrast, would hold 96% of his optimal portfolio in U.S. dollars. Because of the covariance of exchange rates and gold, the exclusion of the latter generates substantial reshuffling. The analysis of the evolution of portfolios over time shows that shares changed dramatically at the beginning of the period and did not begin to approach their March 1981 values until the end of 1975. In the case of the yen and the pound there were oscillations throughout the period. With respect to the dollar share in the optimal portfolio of the U.S. and international investor, it is found that, in the period between late 1974 and mid-1976, a period in which the dollar is considered to have been "strong", a large decline in its optimal share took place.

Costs and Benefits of Privatization: Evidence from Brazil

Although the Brazilian privatization program has been a sweeping endeavor involving more than 100 firms and billions of dollars, most of the studies have been published only in Brazil, and in Portuguese. This paper is the most comprehensive study to date in terms of the companies covered, and includes the most recent data. It looks at the results of privatization in Brazil for a broad range of economic variables to answer the question: Has the widespread popular discontent with the program been justified? The paper also examines the effects of privatization on aspects that affect the development of financial markets, including minority shareholder rights. It concludes with recommendations for democratizing capital ownership through public offers in which workers would be entitled to participate using public sector liabilities such as FGTS deposits.

Solubility of salts in mixed solvents: experimental data and modeling

Phase equilibria in electrolyte systems has been receiving much attention from different research groups. Much of the experimental and theoretical work has been carried out on aqueous systems or in the study of salt effect in vapor-liquid equilibria. However, the design and simulation of unit operations such as, The recently developed extractive crystallization, requires experimental solubility data as well as The ability to correlate and predict electrolyte activity coefficients in mixed-solvents. Moreover, this kind of data can give many relevant indications about ion-solvent interactions and allows the calculation of other thermodynamic properties. Thus, in this work, the solubilities of the salts NaBr and KBr were measured, by an analytical isothermal method, in water, methanol, ethanol and their binary mixed-solvent mixtures, water/methanol, water/ethanol and methanol/ethanol, at temperatures from ambient up to 80 O( The obtained data, were used, together with osmotic and mean ionic molal activity coefficients data available in the literature, to test the capabilities of UNIQUAC-based models for the representation of the thermodynamics properties of these systems. Results are shown and comparisons with other approaches are given

Simulation analysis of IEEE 802.15.4 for wireless networked control systems

The deployment of wireless networks in industrial environments can bring several advantages over their wired counterparts; however, the characteristics of the wireless channels pose challenges to the provisioning of quality of service (QoS) that are not seen in wired networks. This paper provides an analysis of how important QoS parameters, such as message delivery ratio, delay and energy consumption, vary as a function of the number of sensor nodes injecting traffic in IEEE 802.15.4 networks operating in unbeaconed mode. Results show that the peer-to-peer topology enables better performance than the star topology, under the same conditions, indicating that the former is a better option if centralized control is not required. The use of retransmissions increases significantly the reliability of the network; however, even a high number of retransmissions are not enough to provide full reliability when the channel is highly affected by errors. Results also show that presence of hidden nodes can severely degrade the performance of the network, while the reduction of the turnaround time can improve the performance.Fundação para a Ciência e a Tecnologia (FCT

Da Doença Mental à Violência

Resumo: Os comportamentos violentos no âmbito da doença mental têm sido motivo de intenso debate e crescente investigação. A complexidade da questão e a sua importância clínica e social moveram-nos na elaboração do presente artigo, com o qual pretendemos, a partir de uma revisão da literatura existente, a contextualização daquela relação à luz dos actuais conhecimentos científicos