The Effect of social security, demography and technology on retirement

This article investigates the causes in the reduction of labor force participation ofthe old. We argue that the changes in social security policy, in technology and indemography may account for most of the changes in retirement over the second partof the last century in the U.S. economy. We develop a dynamic general equilibriummodel with endogenous retirement that embeds social security legislation. The modelis able to match very closely the increase in the retirement rate of males aged 65 andolder. It also quanti es the isolated impact on retirement and on the solvency of thesocial security system of the di¤erent factors. The model suggests that technologicaland demographic changes had a strong in uence on retirement, so that it would haveincreased signi cantly even if the social security rules had not changed. However, asthe latter became much more generous in the past, changes in social security policycan account not only for a sizeable part of the expansion of retirement, but also for themost of the observed increase in the social security expenses as a share of GDP.

The Effect of Social Security, Demography and Technology on Retirement

This article investigates the causes in the reduction of labor force participation ofthe old. We argue that the changes in social security policy, in technology and indemography may account for most of the changes in retirement over the second partof the last century in the U.S. economy. We develop a dynamic general equilibriummodel with endogenous retirement that embeds social security legislation. The modelis able to match very closely the increase in the retirement rate of males aged 65 andolder. It also quanti es the isolated impact on retirement and on the solvency of thesocial security system of the di¤erent factors. The model suggests that technologicaland demographic changes had a strong in uence on retirement, so that it would haveincreased signi cantly even if the social security rules had not changed. However, asthe latter became much more generous in the past, changes in social security policycan account not only for a sizeable part of the expansion of retirement, but also for themost of the observed increase in the social security expenses as a share of GDP.

The Human Soul as Hoc Aliquid and as Substance in Thomas Aquinas

Thomas Aquinas defines the human soul with the same words of Aristotle: it is the substantial form of a human body potentially alive. However, one of the problems of the Thomistic psychology, according to D. Abel, consists in classifying the human soul by means of terms that are commonly used to name hylomorphic compounds, namely, substance and hoc aliquid. If the human soul is part of a hylomorphic compound, how could it be named as substance and hoc aliquid? The aim of this paper is to show the strategy that underlies this classification used by Aquinas. We suggest that it dates back to Aristotle when he attributes different meanings to the words substance and hoc aliquid. Aquinas’ novelty consists in expanding this semantic field by introducing a meaning that refers exclusively to the human soul, that is, the peculiar sense

Efeito de pré-tratamento de alta pressão na atividade enzimática relacionada com perda de qualidade de pescada congelada

Consumers demand for high quality food stuffs with no preservatives and with extended shelf-life, retaining the quality properties, led to the development of new processing technologies. One of those technologies, studied in this work, is High Pressure Processing (HPP), which has shown good results on fish shelf-life extension, with great importance in fish safety by inactivation of microbial load (mostly pathogenic microorganisms) in refrigerated fish, and inactivation of certain degradative enzymes, mainly in frozen fish. Fish products are usually stored under refrigeration or frozen to maintain their quality and safety patterns. However, there are still several reactions that cause fish degradation. For instance, even under frozen storage, enzymatic activity still occurs. According to the literature, HPP has shown to be a promising pre-treatment to inhibit these enzymes and extend frozen fish-shelf-life. This work aimed to determine the effect of HPP (150 MPa for 2 minutes) and storage temperature (-10, -20 and -30 ºC) on the quality of frozen hake muscle (Merluccius merluccius). It was verified that HPP resulted in a decrease of calpains activity (59 %) after 12 months of storage at -20 ºC and maintained the activity of acid phosphatase, cathepsin B and calpains after 12 months at -30 ºC Furthermore, the quantification of sulfhydryl (SH) groups indicated that the HP treatment results in higher SH content (increase up to 190%), as well as increased storage time (increase up to 120%), being this increase probably related with protein denaturation of fish muscle. This work presents relevant information concerning the employment of HP pre-treatments to reduce enzymatic activity associated to quality loss in frozen European hake (Merluccius merluccius). This type of processing can so be of interest to enhance the quality preservation of frozen hake, as well as of other species.A exigência dos consumidores por produtos alimentares de elevada qualidade sem conservantes e com tempo de prateleira alargado, mantendo a sua qualidade, levou ao desenvolvimento de novas tecnologias para o seu processamento. Uma dessas tecnologias, abordada neste trabalho, é o Processamento por Alta Pressão (HPP), que tem apresentado bons resultados na extensão do tempo de prateleira em peixe, com especial importância para a segurança dos produtos, ao reduzir a carga microbiana (maioritariamente patogénicos) em peixe refrigerado e inibir a atividade de certas enzimas degradativas, principalmente em peixe congelado. Os produtos da pesca são normalmente armazenados em refrigeração ou congelados, de modo a manter os seus padrões de qualidade e segurança. No entanto, há diversas reações que ainda assim causam a degradação do peixe. Por exemplo, mesmo enquanto congelado, o peixe sofre alterações devido à atividade enzimática. De acordo com a literatura, o HPP mostrou grande potencial na inativação dessas enzimas e, consequentemente, na extensão do tempo de prateleira do peixe. Este trabalho visou determinar o efeito de um pré-tratamento por alta pressão (150 MPa por 2 minutos) e temperatura de armazenamento (-10, -20 e -30 ºC) na atividade enzimática do músculo de pescada congelada (Merluccius merluccius). Verificou–se que o pré-tratamento de HP possibilitou a diminuição de atividade das calpaínas (59 %) após 12 meses a -20 ºC e a manutenção das atividades da fosfatase ácida, catepsina B e calpaínas após 12 meses a -30 ºC. Verificou-se ainda um aumento no conteúdo em grupos tiol (SH) com o pré-tratamento (até 190%) e ao longo do tempo de armazenamento (até 120%), estando esse aumento possivelmente relacionado com a desnaturação proteica do músculo de peixe. Este trabalho apresenta assim informação importante relativa à aplicação de pré-tratamentos por alta pressão para reduzir a atividade enzimática associada a deterioração da pescada congelada (Merluccius merluccius). Este tipo de processamento pode assim ser relevante para uma melhor preservação da qualidade da pescada congelada, bem como possivelmente de outras espéciesMestrado em Biotecnologi

Globalization and the Industrial Revolution

This paper argues that trade specialization played an indispensable role in supportingthe Industrial Revolution, allowing the economy to shift resources to the manufacturewithout facing food and raw materials shortage. In our arti cial economy, there are twosectors agriculture and manufacture and the economy is initially closed and under aMalthusian trap. In this economy the industrial revolution entails a transition towards adynamic Heckscher-Ohlin economy. The model reproduces the main stylized facts of thetransition to modern growth and globalization. We show that two-sectors closed-economymodels cannot explain the fall in the value of land relative to wages observed in the 19thcentury and that the transition in this case is much longer than that observed allowingfor trade.

Mediador/Motivador pedagógico: um elo para uma escola reflexiva

Em tempos de mudança, a Escola e os seus actores movem-se no sentido de encontrar um novo rumo. A ideia de uma Escola passiva, parada no tempo, estagnada, legitima a emergência de uma nova postura dos profissionais que desenvolvem a sua acção educativa. Exige-se, hoje, que os professores efectuem o seu percurso profissional mediante a adopção de uma atitude marcadamente reflexiva, que proporcione uma emancipação dos sujeitos, com vista ao desenvolvimento do constructo Escola. É neste seguimento que sugerimos o aparecimento uma nova figura: o Mediador/Motivador Pedagógico. Este pode constituir-se como um elemento preponderante no desenvolvimento e aprendizagem dos professores, implementando uma actividade de regulação reflexiva e colaborativa do processo de desenvolvimento pessoal e profissional dos primeiros. Esta nova figura no panorama educativo aproximar-se-á da figura do supervisor e orientará a sua acção para a promoção da autonomia do professor, que se reconceptualiza, abarcando competências didácticas e supervisivas, mas também investigativas