ELECTION ON RETIREMENT AGE

We analyze the relationship between wage distribution, degree of redistribution of the Social Security and effective retirement age. We develop a two-staged political economy model. In the first stage government chooses the redistribution level of the Social Security Program, according to three different criteria. In second stage the retirement age is elected through a majority voting process by agents with different wages, knowing exactly the redistribution level and voting accordingly. We analyze the different elected retirement age under each government criterium.Wage distribution; retirement age; level of redistribution; median voter

Immigration and Pension Benefits in the Host-country

This paper examines the role that low-skilled immigrant labor force plays in determining the benefits of the public pension of the host population. With an overlapping-generations model in continuous time which allows to identify which groups of native population are better or worse off with immigration and a fully redistributive pension system, we find that the retirement benefits and hence the welfare levels of the host population are affected in a different way whether sharing or not pension benefits with immigrants. In this sense, the youngest local population may prefer, contrary to the oldest ones, a policy of closed borders.Immigration, welfare, pension benefits.

Defined Contribution vs Defined Pension: Reforming the Legal Retirement Age

In this paper we analyze the effects of changing Social Security parameters on the optimal legal retirement age. Two Social Security Systems are studied, with opposite results. When the pension scheme has a defined contribution, a more redistributive system will delay the preferred legal retirement age. On the other hand, when the pension benefit is the defined parameter, the increase in the redistribution level will lower this preferred age.

Aprendizaje cooperativo en educación superior: diferencias en la percepción de la contribución al grupo

Aquest document analitza l'aprenentatge cooperatiu en un grup de treball en el qual s'utilitza metodologia de l'aprenentatge basat en problemes. A més, s'avalua si la percepció que cada component del grup té de la seva aportació a l'aprenentatge cooperatiu és major o menor que la percebuda pels seus companys. S'analitzen diferents aspectes de la feina feta dins el grup, com ara l'esforç efectiu realitzat, la participació, l'organització del grup, la cohesió, la comunicació i la percepció global de la implicació en la feina i l'aprenentatge cooperatiu. S'observa que els estudiants perceben que la seva aportació és major que la percebuda pels seus companys, encara que trobem lleugeres diferències segons els aspectes analitzats.This document analyses cooperative learning in a working group using a problem-based learning methodology. We also evaluate if the perception that each member of the group has of his/her contribution to cooperative learning is greater or lesser than that observed by his/her team-mates. Different elements of the work carried out in the group are analysed, such as the effective effort made, their participation, the organisation of the group, cohesion, communication, and the overall perception of their involvement in the cooperative learning and work. It is observed that the students perceive their contribution as greater than that perceived by their team-mates, although we find slight differences depending on the elements analysed. Este documento analiza el aprendizaje cooperativo en un grupo de trabajo en el que se utiliza metodología del aprendizaje basado en problemas. Además, se evalúa si la percepción que cada componente del grupo tiene de su aportación al aprendizaje cooperativo es mayor o menor que la percibida por sus compañeros. Se analizan diferentes aspectos del trabajo desarrollado dentro del grupo, como son el esfuerzo efectivo realizado, su participación, la organización del grupo, la cohesión, la comunicación y la percepción global de su implicación en el trabajo y el aprendizaje cooperativo. Se observa que los estudiantes perciben que su aportación es mayor que la percibida por sus compañeros, aunque encontramos ligeras diferencias en función de los aspectos analizados

Cooperative learning in higher education: differences in perceptions of contribution to the group

This document analyses cooperative learning in a working group using a problem-based learning methodology. We also evaluate if the perception that each member of the group has of his/her contribution to cooperative learning is greater or lesser than that observed by his/her team-mates. Different elements of the work carried out in the group are analysed, such as the effective effort made, their participation, the organisation of the group, cohesion, communication, and the overall perception of their involvement in the cooperative learning and work. It is observed that the students perceive their contribution as greater than that perceived by their team-mates, although we find slight differences depending on the elements analysed

PII: S0306-4565(00)00033-4

Abstract The effects of parasitisation by Aphidius ervi on the thermoregulatory behaviour of the pea aphid Acyrtosiphon pisum were studied in alfalfa fields and in an experimental thermal gradient. In the field, mummies were found exclusively on the adaxial surface of the upper leaves, and aphids in the mid canopy. The adaxial surface of the upper leaves was ca. 28C hotter that the mid-canopy. In the thermal gradient, the thermal effect (selected minus exposure temperature) was higher in magnitude in non-parasitised than in parasitised aphids; the thermal effects of both types of aphids were linearly and negatively correlated with exposure temperature (i.e. aphids showed negative thermal sensitivity). The thermal sensitivity of parasitised aphids was lower than that of non-parasitised aphids. The results are discussed in relation to hypotheses on factors governing the host-parasite relationship.

The impact of relative position and returns on sacrifice and reciprocity: an experimental study using individual decisions

We present a comprehensive experimental design that makes it possible to characterize other-regarding preferences and their relationship to the decision maker’s relative position. Participants are faced with a large number of decisions involving variations in the trade-offs between own and other’s payoffs, as well as in other potentially important factors like the decision maker’s relative position. We find that: (1) choices are responsive to the cost of helping and hurting others; (2) The weight a decision maker places on others’ monetary payoffs depends on whether the decision maker is in an advantageous or disadvantageous relative position; and (3) We find no evidence of reciprocity of the type linked to menu-dependence. The results of a mixture-model estimation show considerable heterogeneity in subjects’ motivations and confirm the absence of reciprocal motives. Pure selfish behavior is the most frequently observed behavior. Among the subjects exhibiting social preferences, social-welfare maximization is the most frequent, followed by inequality-aversion and by competitiveness