A Dynamic Model of Retirement and Social Security Reform Expectations: A Solution to the New Early Retirement Puzzle

The need for Social Security Reform in the next years is hardly a matter of debate. Therefore, the widespread believe among Americans that Social Security will not be able to pay benefits in the long run at the level that was anticipated, does not come as a surprise. The government acknowledges the situation, and predicts that substantial benefits cuts will be necessary, yet no legislation has been passed to tackle the problem. Researchers, however, have rarely modeled the uncertainty over Social Security reform and benefit levels, and how they affect claiming behavior and retirement. The purpose of this paper is to assess the extent to which these perceptions of future cuts might explain the puzzle of earlier take-up despite bigger penalties to doing so in the presence of increasing longevity. By introducing a small amount of uncertainty (based on self-reported responses to questions regarding expectations over future cuts) of a relatively small cut (compared with what the government reports as necessary to solve the crisis) in a dynamic life-cycle model of retirement, we are able to match the claiming behavior observed in the data, without relying on heterogeneous preferences. Our results support the hypothesis that expectations over future benefits are affecting current behavior. We find that a mis-specified dynamic retirement model would erroneously predict that an increase in the NRA would delay claiming behavior and increase labor supply at older ages. Once the appropriate earnings test incentives are modeled, and we account for the probability of reforms to the system, an increase in the NRA has little effect on claiming behavior, and it can even increase the proportion of individuals claiming before the NRA.

Many-body interactions in a quantum wire in the integer quantum Hall regime: suppression of exchange-enhanced g factor

The collapse of Hall gaps in the integer quantum Hall liquid in a quantum wire is investigated. Motivated by recent experiment [Pallecchi et al. PRB 65, 125303 (2002)] previous approaches are extended to treat confinement effects and the exchanged enhanced g-factor in quantum wires. Two scenarios for the collapse of the $\nu =1$ state are discussed. In the first one the $\nu =1$ state becomes unstable at $B_{cr}^{(1)}$, due to the exchange interaction and correlation effects, coming from the edge-states screening. In the second scenario, a transition to the $\nu =2$ state occurs at $B_{cr}^{(2)}$, with a smaller effective channel width, caused by the redistribution of the charge density. This effect turns the Hartree interaction essential in calculating the total energy and changes $B_{cr}^{(2)}$ drastically. In both scenarios, the exchange enhanced g-factor is suppressed for magnetic fields lower than $B_{cr}$. Phase diagrams for the Hall gap collapse are determined. The critical fields, activation energy, and optical $g$-factor obtained are compared with experiments. Within the accuracy of the available data, the first scenario is most probable to be realized.Comment: 11 pages, 10 figure

Improper program management-induced system archetypes

Projects and programs: those two concepts are not one same side of a coin or even two different sides of a same coin. Despite the growing consensus among the project management community around the differences between the two topics, many organizations still fail to adopt a governance framework that considers such differences. The consequence is a domino effect: programs are treated as large projects, short-term focus values only the delivery of capabilities by component projects, an unhealthy internal competition between said projects is established, the organization's resources are burdened, and ultimately, organizations fail to realize benefits to their full potential. In this paper, we show that such situation fits into two well-known system archetypes, namely "Success to the Successful" and "Tragedy of the Commons". As case-study, we present a large, multi-year, multi-million Brazilian Government initiative, as well as the results achieved by said initiative, before and after a proper governance framework was in place. We also use System Dynamics (SD) to simulate and demonstrate said results, but also to forecast the expected results for the years yet to come, now that the programs and projects are given the proper treatment

Estado da qualidade da água de origem subterrânea no concelho de Alcochete com utilização de ferramentas SIG

A maior parte da água necessária para atividades domésticas, agrícolas, lúdicas e industriais no concelho de Alcochete (Portugal) provêm de origens subterrâneas. Contudo, subsistem dúvidas sobre o estado da sua qualidade e a sua apetência para as utilizações atuais. O estudo da hidrogeoquímica permite estabelecer relações entre o meio aquoso e o meio geológico, refletindo a influência da litologia local e dos solos na qualidade da água. Permite, ainda, determinar sentidos de escoamento, áreas de recarga e descarga e conhecer unidades aquíferas, bem como identificar focos de poluição e estabelecer medidas para a utilização sustentável da água. Foram recolhidas amostras em 67 captações utilizadas como origens de água para várias utilizações. Dada a quantidade e complexa informação que foi necessário recolher, manusear e interpretar, a utilização de Sistemas de Informação Geográfica (SIG) foi de grande utilidade para georreferenciar dados, criar bases de dados relacionais e gerar cartas de aptidão para a utilização das águas subterrâneas. As águas captadas em poço, essencialmente do tipo cloretadas cálcicas, na generalidade, não apresentam qualidade mínima para serem captadas para produção de água para consumo humano, enquanto que 70,7% das origens de águas oriundas de furos, essencialmente cloretadas sódicas, apresentam qualidade mínima para aquela utilização. Ambos os tipos de água apresentam qualidade para utilização na rega agrícola, mas poucas amostras cumprem os valores recomendados para esta utilização. Assim, é urgente a implementação de uma estratégia de gestão dos recursos hídricos no concelho, afim de melhor proteger estas origens de água

Realisability of production recipes

There is a rising demand for customised products with a high degree of complexity. To meet these demands, manufacturing lines are increasingly becoming autonomous, networked, and intelligent, with production lines being virtualised into a manufacturing cloud, and advertised either internally to a company, or externally in a public cloud. In this paper, we present a novel approach to two key problems in such future manufacturing systems: the realisability problem (whether a product can be manufactured by a set of manufacturing resources) and the control problem (how a particular product should be manufactured). We show how both production recipes specifying the steps necessary to manufacture a particular product, and manufacturing resources and their topology can be formalised as labelled transition systems, and define a novel simulation relation which captures what it means for a recipe to be realisable on a production topology. We show how a controller that can orchestrate the resources in order to manufacture the product on the topology can be extracted from the simulation relation, and give an algorithm to compute a simulation relation and a controller

Realisability of production recipes

There is a rising demand for customised products with a high degree of complexity. To meet these demands, manufacturing lines are increasingly becoming autonomous, networked, and intelligent, with production lines being virtualised into a manufacturing cloud, and advertised either internally to a company, or externally in a public cloud. In this paper, we present a novel approach to two key problems in such future manufacturing systems: the realisability problem (whether a product can be manufactured by a set of manufacturing resources) and the control problem (how a particular product should be manufactured). We show how both production recipes specifying the steps necessary to manufacture a particular product, and manufacturing resources and their topology can be formalised as labelled transition systems, and define a novel simulation relation which captures what it means for a recipe to be realisable on a production topology. We show how a controller that can orchestrate the resources in order to manufacture the product on the topology can be extracted from the simulation relation, and give an algorithm to compute a simulation relation and a controller

Clusters of Galaxies: New Results from the CLEF Hydrodynamics Simulation

Preliminary results are presented from the CLEF hydrodynamics simulation, a large (N=2(428)^3 particles within a 200 Mpc/h comoving box) simulation of the LCDM cosmology that includes both radiative cooling and a simple model for galactic feedback. Specifically, we focus on the X-ray properties of the simulated clusters at z=0 and demonstrate a reasonable level of agreement between simulated and observed cluster scaling relations.Comment: 7 pages, 4 figures, accepted for publication in Advances in Space Research (proceedings of the COSPAR 2004 Assembly, Paris