The effective number of relevant parties : how voting power improves Laakso-Taagepera’s index

This paper proposes a new method to evaluate the number of rel- evant parties in an assembly. The most widespread indicator of frag- mentation used in comparative politics is the ‘Effective Number of Par- ties’(ENP), designed by Laakso and Taagepera (1979). Taking both the number of parties and their relative weights into account, the ENP is arguably a good parsimonious operationalization of the number of ‘relevant’ parties. This index however produces misleading results in single-party ma jority situations as it still indicates that more than one party is relevant in terms of government formation. We propose to modify the ENP formula by replacing proportions of seats by voting power measures. This improved index behaves more in line with Sar- tori’s definition of relevance, without requiring additional information in its construction.Voting power indices; Effective Number of Parties; Party system fragmentation; Relevance; Coalition Formation

Measuring Poverty and Inequality in a Computable General Equilibrium Model

This paper aims to evaluate the relevance of different types of macroeconomic general equilibrium modelling for measuring the impact of economic policy shocks on the incidence of poverty and on the distribution of income. In the literature three approaches are identified. The first is based on a traditional form of the CGEM which specifies a large number of households. In this case, we can only observe inter group income inequalities. The next uses survey data to estimate the distribution function and average variations by group, which allows one to estimate the evolution of poverty. The third approach, which we present in detail, includes individual data directly in the general equilibrium model according to the principles of micro simulations. This treatment provides a more reliable picture of income distribution but is also more complex. Given this, we develop, within a co-ordinated statistical framework representing an archetypal economy, the three types of model described above. More precisely, this exercise allows us to break down the contribution of average income variations, of the poverty line, and of income distribution in the evolution of the main poverty indicators. The results obtained show the importance of intra group information and therefore the relevance of micro simulation exercises.General Equilibrium Models, Micro Simulation, Poverty, Inequality

Effects of Immigration on Labour Markets and Government Budgets - An Overview

The paper provides an overview on recent trends of immigration in OECD countries and on the possible effects of immigration on labour markets and government budgets. It also discusses migration policies from an economic point of view. By bringing together a bulk of international literature on labour market and fiscal effects of migration in a systematic way it provides a framework for assessing the economic effects of migration and improving the knowledge base for migration policies.migration, labour markets, fiscal effects of migration

Friction stir welding of AZ31 magnesium alloy rolled sheets: Influence of processing parameters

The temperature evolution during friction stir welding (FSW) and the resulting residual stresses of AZ31 Mg alloy were studied to get a better understanding of the mechanisms involved in this process. The relationship between the processing parameters, the heat and plastic deformation produced and the resulting microstructure and mechanical properties was investigated. Increasing the shoulder diameter or the tool rotation speed or decreasing the welding speed produced an increase in the heat generated during the process and then promoted grain growth. The temperature distribution on the advancing side and on the retreating side differed, and stress levels were higher on the retreating side. The grain size heterogeneity produced by FSW was not the prevailing cause of failure.AEROMAG Project N°AST4-CT-2005-516152 European Unio

Identification par télédétection de l'accident de la Sanaga (Cameroun) : sa position dans le contexte des grands accidents d'Afrique Centrale et de la limite nord du craton congolais

L'accident Bozoum-N'délé identifié en République Centrafricaine se prolonge vers l'Ouest jusqu'à l'Atlantique, en suivant partiellement le cours du fleuve Sanaga. Cet accident Sanaga-N'délé dextre est le plus méridional et le plus continu des linéaments d'Afrique Centrale. Légèrement oblique sur la limite septentrionale du craton congolais, qui reste cependant imprécise, cet accident panafricain marque au sein du socle remobilisé au Panafricain le glissement dextre d'une partie NW par rapport à une partie SE restée solidaire du craton congolais. (Résumé d'auteur

Neotectonics of the subandes-Brazilian craton boundary using geomorphological data : the Maranon and Beni basins

Active and abandoned fluvial traces are used together with neotectonic, seismotectonic and subsurface structural data to study the neotectonic evolution of the Peruvian and Bolivian foreland basins. The Maranon Basin to the north and the Beni Basin to the south are located near the ends of the Peru-Bolivia Andean segment. This segment lies above the flat-slab subduction of the Nazca plate beneath the Andes. The surface of these basins shows a complex network of present-day rivers and fossil river traces. A relative chronology of the river traces deduced from morphological criteria allows the identification of successive shifting of fluvial belts up to the present position of the main rivers. As it enters the Ucamara Depression, the Ucayali River is deflected to the northeast. Successive shifts of the deflection point are directed upstream along the upper reaches of the river along the foothills. Simultaneously the Maranon River is deflected to the north, lining up with the straight, NE-trending lower reaches of the Huallaga River. In the central part of the depression the rivers trend northeast-southwest, parallel to the main strike of the basement faults. This regional trend is also parallel to the greatest principal stress observed both to the east and the west of the depression, and to the neotectonic faults on the margin of the Brazilian craton. The Beni Basin is characterized by a counterclockwise shift of the Beni River. Successive shifts of the river involve the northward migration of the deflection point of the Beni River as it enters the basin. A fault connected to the foothill margin controls this downstream movement. Recent erosion of the flood plain surface to the east suggests a tendency of the craton margin to ascend. No coaxial stress resulting from either plate motion or from collapse of the Andean topography seems to control the directional shift of rivers in the basins. (Résumé d'auteur

Néotectonique du Piémont amazonien des Andes centrales du Pérou (San Ramon)

Cet article présente une étude de la néotectonique du bassin de San Ramon (Pérou, Andes centrales). La formation Canon, constituée principalement de conglomérats d'age Pliocène, est déformée par un racourcissement de direction NE-SO et chevauchée par les terrains de la cordillère le long de la bordure du bassin. La reprise de l'érosion au Quaternaire détermine l'apparition d'importants cônes de déjection au piémont de la cordillèr

Fluvial shifting in the Ucamara depression as related to the neotectonics of the Andean foreland Brazilian craton border (Peru)

Les morphologies fluviales actives et fossiles visibles à la surface de la dépression Ucamara (partie sud du bassin du Maranon) ont été étudiées à partir d'images SLAR, Landsat et d'observations de terrain. Les rivières correspondant à des ceintures de méandres actives (Maranon, Ucayali et Tapiche) drainent des eaux blanches (silteuses) provenant des Andes. Les interfluves sont drainés par des cours d'eaux noires (acides organiques) comme les rivières Samiria et Pacaya et montrent des caractéristiques de sous-adaptation (underfitness) interprétées comme résultant de l'abandon de larges rivières d'eaux blanches. La position dans la dépression des cours d'eaux noires suggère des avulsions successives du Maranon et de l'Ucayali, respectivement vers le nord de 50 km et vers le sud de 75 km, durant la période récente, probablement au cours de l'Holocène. Le contexte géodynamique dans lequel se trouve la dépression Ucamara suggère d'étroites relations entre l'activité tectonique récente et les avulsions successives du Maranon et de l'Ucayali. (Résumé d'auteur