Le système de retraite américain : impact de la crise et tendances de long terme

This paper presents a summary of the U.S. pension system. First, our goal is to explain how unfunded and funded pension schemes work. We also study how the economic and financial crisis has affected these different schemes. Moreover, we examine the official long-run forecasts of the evolution of the unfunded pension scheme (OASDI) according to various economic and demographic scenarios. Finally, we study the nature of the public debate and the policy options for government action. Our work shows that the crisis has not jeopardized the financing of the unfunded pension scheme because the latter stays in surplus in the short and medium term. The crisis only reduced the amount of this surplus. In the long term, the accumulated trust fund should be insufficient to cover future primary deficits. A major reform can not be excluded from 2020 onwards. The financial crisis has sharply devaluated the assets of the funded pension schemes, which conducts to a problem of survival for some pension funds. Without public financial support or a sufficient recovery in financial markets, a drop in the amount of pensions is possible.US economy, pension schemes, economic crisis.

Fiscal incidence of unfunded pension system: an analytical investigation

This paper deals with the particular fiscal incidence induced by an unfunded pension system. That consists to understand how the financing and the calculus of pensions modify the transitory and long run macroeconomic dynamics. We develop an OLG model with endogenous labour supply in an economy with productive capital. A tax on the labour income is used to finance pensions. During the retirement, a part of the amount of the pension is exogenous and the other part is linked to the contributive effort during the working period. The method of analysis is not numerical but analytical. The results concern the identification of the steady state and the transitory dynamics. Then we proceed to a sensitive study of the dynamics with respect to changes of the payroll tax or the degree of contribution.monetary retirement, labor income tax, OLG models.

Pension rules and implicit marginal tax rate in France

International audienc

Dynamic Microsimulation Models Using to Analyze Retirement Systems Reforms: An Essay of Synthesis

Dynamic microsimulation models applied to economics were first introduced in the United States at the end of the 1960’s. Since the 1980’s, they have been rapidly developing due to the increase in computational capabilities and to the availability of longitudinal data. Dynamic microsimulation provides a tool for analysing nonlinear pension systems by simulating individual trajectories of heterogeneous economic agents. Hence, this method highly improves the understanding of pension reforms, the evaluation of pensioners’ rights and intra- as well as inter-generational redistributions. Moreover, it takes into account methods and results from other kinds of analyses, such as behavioural micro-econometrics. This article sets out a synthesis of the achievements of dynamic microsimulation studies of pension systems. The first section draws up a typology of useful methods in the field of pension systems studies. In the second section, a technical assessment of the method is carried out. Various sources of errors in the calculation of individual trajectories and in the determination of aggregated results are examined. Two simple numerical examples illustrate some properties of stochastic simulations. Our analysis recommends better knowledge of the statistical properties of dynamic microsimulation. It favours setting up databases which directly answer the needs of dynamic microsimulation. Finally, the third section reviews an extensive range of dynamic microsimulation models from across OECD countries, and sums up the achievements of the French INSEE model, DESTINIE.Dynamic Microsimulation, long run prospective studies, unfunded retirement systems modelling

Towards agile cross-platform application development with Smalltalk and Model Driven Engineering

International audienceNowadays, general public applications or specific infor-mation systems must be able to run on mobile platforms as well as on conventional platforms. Because developers have to deal with mobile platform specificities, this constraint si-gnificantly lessen the benefits of agile methods and as a consequence impacts on the application development cost. Many research works aim at reducing the development cost. Prototyping as well as automatic code generation have been investigated by the community. In this article, we present Dali, a framework that uses both Smalltalk and Model Dri-ven Engineering. With Dali, an application model can be de-signed for multiple platforms and interpreted before code generation. An execution platform is modelled as a set of constraints over a context. These constraints can affect the presentation of the Graphical User-Interface (GUI) but also the overall behaviour of an application

Politiques de santé dans un modèle macroéconomique

Cet article propose une approche théorique de l’incidence des politiques de santé (contingentement, ticket modérateur, contrôle qualitatif) ; la voie envisagée est une analyse micro-macroéconomique. Le comportement de l’offre médicale est construit sur un choix d’allocation du temps de travail entre deux activités : l’une utile et l’autre inutile. Ce fondement microéconomique des arbitrages médicaux est ensuite intégré dans un modèle de croissance avec accumulation de capital ; les conclusions concernent alors les évolutions des dépenses de santé, du bien-être et de l’accumulation de patrimoine au regard de différents plans de politique de santé.This article offers a micro-macro-economic approach for the incidence of policies concerning health care. The medical supply behaviour is built using a working-time allocation choice between various qualities of care. This choice is assimilate to a decomposition of health care in two activities : one effective and another non-effective. This microeconomic foundation of health supply is then integrated in a model of growth with capital accumulation. The conclusions concern the evolution of health expenditures, the population’s welfare and wealth accumulation, with respect to various policies

Crystal structure of undecaprenyl-pyrophosphate phosphatase and its role in peptidoglycan biosynthesis

As a protective envelope surrounding the bacterial cell, the peptidoglycan sacculus is a site of vulnerability and an antibiotic target. Peptidoglycan components, assembled in the cytoplasm, are shuttled across the membrane in a cycle that uses undecaprenyl-phosphate. A product of peptidoglycan synthesis, undecaprenyl-pyrophosphate, is converted to undecaprenyl-phosphate for reuse in the cycle by the membrane integral pyrophosphatase, BacA. To understand how BacA functions, we determine its crystal structure at 2.6 Å resolution. The enzyme is open to the periplasm and to the periplasmic leaflet via a pocket that extends into the membrane. Conserved residues map to the pocket where pyrophosphorolysis occurs. BacA incorporates an interdigitated inverted topology repeat, a topology type thus far only reported in transporters and channels. This unique topology raises issues regarding the ancestry of BacA, the possibility that BacA has alternate active sites on either side of the membrane and its possible function as a flippase

University education and cervical artery dissection

We investigated whether university education is more likely in cervical artery dissection (CeAD)-patients than in age- and sex-matched patients with ischemic stroke (IS) due to other causes (non-CeAD-IS-patients). Patients from the Cervical Artery Dissection and Ischemic Stroke Patients study with documented self-reported profession before onset of IS due to CeAD (n = 715) or non-CeAD causes (n = 631) were analyzed. In the reported profession, the absence or presence of university education was assessed. Professions could be rated as academic or non-academic in 518 CeAD and 456 non-CeAD patients. Clinical outcome at 3 months was defined as excellent if modified Rankin Scale was 0-1. University education was more frequent in CeAD-patients (100 of 518, 19.3%) than in non-CeAD-IS-patients (61 of 456, 13.4%, p = 0.008). CeAD-patients with and without university education differed significantly with regard to smoking (39 vs. 57%, p = 0.001) and excellent outcome (80 vs. 66%, p = 0.004). In logistic regression analysis, university education was associated with excellent outcome in CeAD-patients (OR 2.44, 95% CI 1.37-5.38) independent of other outcome predictors such as age (OR 0.97, 95% CI 0.84-0.99), NIHSS (OR 0.80, 95% CI 0.76-0.84) and local signs (OR 2.77, 95% CI 1.37-5.57). We observed a higher rate of university education in patients with CeAD compared with non-CeAD patients in our study population. University education was associated with favorable outcome in CeAD-patients. The mechanism behind this association remains unclear.Peer reviewe