The Demographic Transition in Closed and Open Economies: A Tale of Two Regions

This paper constructs a general equilibrium overlapping generation model to evaluate quantitatively how demographic transition (falling mortality and fertility rates) affects aggregate variables (wages, interest rate, output), and inter-generational welfare in closed and open economies. We perform this analysis for two economies calibrated to resemble the North (US and Europe) and Latin America. Our simulations suggest that the demographic transition could have generated income per capita growth up to 0. 5% per year in excess of steady-state growth in the past 50 years in Latin America and 0. 3% in the North.

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Scalable interconnections for remote indirect exciton systems based on acoustic transport

Excitons, quasiparticles consisting of electron-hole pairs bound by the Coulomb interaction, are a potential medium for the processing of photonic information in the solid state. Information processing via excitons requires efficient techniques for the transport and manipulation of these uncharged particles.We have carried out a detailed investigation of the transport of excitons in GaAs quantum wells by surface acousticwaves. Based on these results, we introduce here a concept for the interconnection of multiple remote exciton systems based on the long-range transport of dipolar excitons by a network of configurable interconnects driven by acoustic wave beams. By combining this network with electrostatic gates, we demonstrate an integrated exciton multiplexer capable of interconnecting, gating, and routing exciton systems separated by millimeter distances. The multiplexer provides a scalable platform for the manipulation of exciton fluids with potential applications in information processingFinancial support by DFG Project No. SA 598/

A low-cost stereo video system for measuring directional wind waves

Typical oceanographic instruments are expensive, complex to build, and hard to deploy and require constant and specialized maintenance. In this paper, we present a cheap and simple technique to estimate a three-dimensional surface elevation map, n (x, y, t), the directional spectrum, and the main sea state parameters using inexpensive smartphones. The proposed methodology uses Time Lagged Cross Correlation (TLCC) between the audio signals from two independent video records to perform the frame synchronization. This makes the system much easier to deploy, where the main requirement is a fixed or moving platform close to the sea. The time records are mostly limited by the equipment storage space and battery life, although it can be easily replaced or recharged. Here, we pose the basis for an inexpensive yet powerful stereo reconstruction device and discuss its capabilities and limitations. The smartphone system capabilities were illustrated here by near shore experiment, at Leme beach in the Southeast of Brazil, and the results were compared against a pressure sensor. For this particular setup, the root mean square error in terms of significant wave height is of the order of 11% with perfect estimation of the peak period. The results are promising and demonstrate the validity and applicability of the technique

Global Demographic Trends and Social Security Reform

The issue of pension reform has recently received a considerable amount of attention, both in developed and in developing countries. In the former group the interest arises from the fact that current demographic trends -which project a dramatic increase in dependency ratios over the nex 20 to 40 years- make the unfunded, pay-as-you-go pension systems currently in place in most of these countries, unsustainable. Some countries in Latin America, on the other hand, have pioneered the move towards funded private pension systems. Chile was the first country to move in that direction, followed in recent years by many others, including México, Colombia and Argentina. The issue is also being discussed in Brazil.Demographic, Social Security Reform

Acceptability of Male Circumcision for the Prevention of HIV/AIDS in the Dominican Republic

Male circumcision (MC) is an effective strategy to prevent HIV infection in heterosexual men. To our knowledge, there are no studies of the acceptability of this procedure in the Dominican Republic (DR). The main objective of this study was to assess the acceptability of MC to prevent HIV transmission among men ages 18 to 50 years in the Altagracia Province in the Dominican Republic. Because differences in culture and beliefs between Haitians and Dominicans could potentially influence their acceptability of MC, we conducted a comparative analysis based on national origin.A survey was administered to a convenience sample of 368 men. The questionnaire was divided in 3 sections: 1) Background demographics (including national origin), 2) Male circumcision and 3) Sexual health. Stratified and logistic multivariate regression analyses were performed to identify factors associated with the acceptability of MC.The sample consisted of 238 (65%) Dominicans and 130 (35%) Haitian immigrants. Almost all participants were uncircumcised (95%) and about half (52%) were single. The overall acceptability of MC was 29%. The number of men willing to be circumcised increased to 67% after an information session explaining the benefits of the procedure. 74% of men reported that they would be willing to circumcise their sons after hearing that information. In multivariate analysis, Haitian nationality (OR=1.86, 95% CI 1.01-3.41), knowing that circumcision improves hygiene (OR=2.78, 95% CI 1.29-6.0) and not believing that circumcision decreases sexual pleasure (OR=2.18, 95% CI 1.20-3.94) were associated with a higher acceptability of the procedure. Although age was not significantly associated with the willingness to be circumcised in the multivariate analysis, stratified analysis based on national origin suggested that younger Dominicans (<30 years of age) are more likely to accept the procedure when compared to their older counterparts (OR=2.17, 95% CI 1.14-4.12).An important number of sexually active men in the DR may be willing to be circumcised if educational resources detailing the benefits of the procedure are made available. These educational activities would constitute a great opportunity to teach about sexual health and reinforce safe sex practices