On the Optimality of PAYG Pension Systems in an Endogenous Fertility Setting

In order to help in designing an accurate pension reform, we determine the optimal resource allocation in an endogenous fertility model generating a demographic transition. Extending Samuelson’s (1975) work in such a setting, we analyze the problem of the interiority of the optimal solution and discuss the serendipity theorem. We then characterize the decentralization of the first best, showing that a pension policy linking pension benefits to the number of children constitutes an optimal social security program able to restore both the optimal capital stock and the optimal rate of pupulation growth as a unique instrument. We also show that neither a Beveridgean pension scheme nor a Bismarckian one can decentralize the first best.demographic transition;fertility;pensions;golden rule

La sustitución C>A en el NT 46 en la región 3’ UTR (Alfa Complex Protected Region) del gen ALFA 1 de globina ¿mutación o polimorfismo?

PC-048 Antecedentes: Las regiones no traducidas [UnTranslated Region (UTR)] desempeñan un papel crucial en la regulación postranscripcional de la expresión génica, incluida la modulación del transporte de ARNm fuera del núcleo, la eficacia de la traducción, la localización subcelular y la estabilidad. La estabilidad del ARNm es un factor decisivo para el desarrollo y funcionamiento normal de los glóbulos rojos. En el caso del ARNm de a-globina, los principales determinantes de la estabilidad se localizan en el extremo 3’ UTR; en concreto, se han identificado 3 áreas discontinuas ricas en citosina (C) ubicadas entre los nucleótidos (nt) 25 y 70 corriente abajo del codon de parada. Estas áreas ricas en C son responsables de atraer a una ribonucleoproteína (RNP) llamada a-globina poli (C) de unión o a-complejo proteína (aCP) para estabilizar la molécula de ARNm. Wagoner et al. demostraron a través del análisis in vitro que cualquier mutación en estos elementos ricos en C dificulta la unión del ARNm de a-globina con el aCP y desestabiliza al ARNm. Objetivos: Presentamos 15 pacientes con la sustitución C>A en el extremo 3’UTR del gen a1 de globina, localizada en la región del complejo a (aCP), la cual podría causar a-talasemia no deleción al afectar a la estabilidad postranscripcional (estabilidad del ARNm) o tratarse de un polimorfismo. Métodos: Se han estudiado 15 pacientes pertenecientes a 12 familias, todas de origen español excepto dos, una procedente de Rumanía y otra de Marruecos. Las edades estuvieron comprendidas entre 2 y 67 años. Todos fueron estudiados por presentar microcitosis e hipocromía sin ..

Optimal population growth and social security reform with heterogeneous agents

In this paper we propose a pension policy that would isolate the social security system from any financial crisis resulting from changes in population structure. This policy consists of linking social security benefits to the fertility behaviour of the individual. We present a theoretical analysis to show that this policy restores the optimality of the capital-labour ratio and the population growth rate in an overlapping-generations model with endogenous fertility. We extend this analysis to the case of heterogeneous agents with respect to their preferences towards children.pay-as-you-go social security system, overlapping-generations model, endogenous fertility, heterogeneous agents, optimal population growth

Pensions with heterogenous individuals and endogenous fertility

Pay-as-you-go social security, Endogenous fertility, Redistribution, H55, J13,

Could shading reduce the negative impacts of drought on coffee? A morphophysiological analysis

Based on indirect evidence, it was previously suggested that shading could attenuate the negative impacts of drought on coffee (Coffea arabica), a tropical crop species native to shady environments. A variety (47) of morphological and physiological traits were examined in plants grown in 30‐l pots in either full sunlight or 85% shade for 8 months, after which a 4‐month water shortage was implemented. Overall, the traits showed weak or negligible responses to the light × water interaction, explaining less than 10% of the total data variation. Only slight variations in biomass allocation were observed in the combined shade and drought treatment. Differences in relative growth rates were mainly associated with physiological and not with morphological adjustments. In high light, drought constrained the photosynthetic rate through stomatal limitations with no sign of apparent photoinhibition; in low light, such constraints were apparently linked to biochemical factors. Sun‐grown plants displayed osmotic adjustments, decreased tissue elasticities and improved long‐term water use efficiencies, especially under drought. Regardless of the water availability, higher concentrations of lipids, total phenols, total soluble sugars and lignin were found in high light compared to shade conditions, in contrast to the effects on cellulose and hemicellulose concentrations. Proline concentrations increased in water‐deprived plants, particularly those grown under full sun. Phenotypic plasticity was much higher in response to the light than to the water supply. Overall, shading did not alleviate the negative impacts of drought on the coffee tree

The optimum growth rate for population reconsidered

Optimal population, Serendipity theorem, Debt, E21, E25, H55,