Demographic changes and economic growth: a macroeconomic projection for 2020

Exploring the economic consequences of demographic changes is often carried out within simple accounting frameworks. Such approaches consist of projecting the impact of ageing on social security expenditures under exogenous assumptions about economic growth, productivity, wages and employment. Alternative attempts to consider richer interactions between economic and demographic variables are carried out with calibrated computable general equilibrium models with overlapping generations. These models are basically neoclassical. Up to now in France, this question seldom has been examined with macroeconometric models of keynesian inspiration. Studying the results provided by such models for France may therefore be of interest. This is the purpose of this work, which presents an economic outlook for 2020 carried out with MESANGE macroeconometric model. This model has short term keynesian and long term neo-classical properties. This exercise integrates the impact of demographic changes on savings, consumption, social expenditures and disequilibrium on the labour market. Labour force projections and the natural dynamics of the model lead to employment levels that remain insufficient to ensure balance in social accounts. Additional taxes would therefore be required. Two possibilities are explored: the CSG or Generalized Social Contribution (a constant tax rate on capital and labor income) or employers and employees social contributions (with or without an impact of employees contributions on the fiscal wedge). The model predicts that the level of employment is less penalised by the former modality. We also explore the consequences of tougher conditions to get full pensions which, at the 2020 horizon, would lead to a one-year increase of the age of new retirees. In this case, the increase of the CSG that would be required to meet Maastricht criteria amounts to 4.3 points. Choosing between CSG and social contributions might nevertheless depend on other considerations, such as their incidence on the relative standards of living of workers and pensioners, or the wish to keep a strong correspondence between pension benefits and contributions paid during working life.retirement, ageing, growth, sustainability of public spending

Evaluating the ecological realism of plant species distribution models with ecological indicator values

Species distribution models (SDMs) are routinely applied to assess current as well as future species distributions, for example to assess impacts of future environmental change on biodiversity or to underpin conservation planning. It has been repeatedly emphasized that SDMs should be evaluated based not only on their goodness of fit to the data, but also on the realism of the modelled ecological responses. However, possibilities for the latter are hampered by limited knowledge on the true responses as well as a lack of quantitative evaluation methods. Here we compared modelled niche optima obtained from European-scale SDMs of 1,476 terrestrial vascular plant species with empirical ecological indicator values indicating the preferences of plant species for key environmental conditions. For each plant species we first fitted an ensemble SDM including three modeling techniques (GLM, GAM and BRT) and extracted niche optima for climate, soil, land use and nitrogen deposition variables with a large explanatory power for the occurrence of that species. We then compared these SDM-derived niche optima with the ecological indicator values by means of bivariate correlation analysis. We found weak to moderate correlations in the expected direction between the SDM-derived niche optima and ecological indicator values. The strongest correlation occurred between the modelled optima for growing degree days and the ecological indicator values for temperature. Correlations were weaker for SDM-derived niche optima with a more distal relationship to ecological indicator values (notably precipitation and soil moisture). Further, correlations were consistently highest for BRT, followed by GLM and GAM. Our method gives insight into the ecological realism of modelled niche optima and projected core habitats and can be used to improve SDMs by making a more informed selection of environmental variables and modeling techniques

Impermeability effects in three-dimensional vesicles

We analyse the effects that the impermeability constraint induces on the equilibrium shapes of a three-dimensional vesicle hosting a rigid inclusion. A given alteration of the inclusion and/or vesicle parameters leads to shape modifications of different orders of magnitude, when applied to permeable or impermeable vesicles. Moreover, the enclosed-volume constraint wrecks the uniqueness of stationary equilibrium shapes, and gives rise to pear-shaped or stomatocyte-like vesicles.Comment: 16 pages, 7 figure

Relations between Au / Sn-W mineralizations and late hercynian granite: Preliminary results from the Schistose Domain of Galicia-Trás-os-Montes Zone, Spain

International audienceAu and W-Sn mineralization of the Schistose Domain of Galicia-Trás-os-Montes are spatially related to late hercynian granites. The Bruès (Au) and the Mina Soriana W-(Sn) deposits are studied. Both show some similarities and are assumed to form in the same tectonic and metamorphic context, on top of the granites. The role of the granite as a source for mineralizing fluids and rheological control for vein emplacement is re-adressed and discussed

Consumer credit in comparative perspective

We review the literature in sociology and related fields on the fast global growth of consumer credit and debt and the possible explanations for this expansion. We describe the ways people interact with the strongly segmented consumer credit system around the world—more specifically, the way they access credit and the way they are held accountable for their debt. We then report on research on two areas in which consumer credit is consequential: its effects on social relations and on physical and mental health. Throughout the article, we point out national variations and discuss explanations for these differences. We conclude with a brief discussion of the future tasks and challenges of comparative research on consumer credit.Accepted manuscrip