The main obstacles to firms' growth in Senegal: Implications for the long run

Productivity gains are the prime engine of economic growth. This paper uses a rich amount of firms' accounting information from the Single Information Collecting Centre in Senegal over the period 1998-2011. To investigate the two main obstacles to growth, poor education and poor access to electricity supply, we aggregate the firms' data at the sectoral level. Our findings corroborate the conclusion of a recent report by the African Development Bank suggesting the importance of primary and vocational education. Another key conclusion drawn in the AfDB report is that the main obstacle to production is the poor access to electricity and the low quality of infrastructure. Based upon a World Bank indicator of access and some strong but reasonable assumptions regarding the sectoral demand for electricity, we estimate the impact of the electricity access on firms' total factor productivity

On equilibrium existence with endogenous restricted financial participation

Allowing for durable commodities, we prove equilibrium existence in an abstract incomplete market economy with endogenous restricted financial participation without requiring financial survival assumptions. We apply our results to general financial structures including nominal, real and collateralized asset markets.Equilibrium, Incomplete markets, Endogenous restricted nancial participation

Dynamic modelling of the behaviour of the quarkiss earthen dam under seismic loads

The dynamic modelling of the behaviour of the Ouarkiss earthen dam under seismic loads was performed using the finite elements method (FEM), with an approach in effective stresses. The soil behaviour is described by the Mohr-Coulomb criterion. A numerical method and a procedure of analysis are presented in this work. The seismic response of an earthen dam was evaluated. Particular emphasis is placed on the calculation of stresses, displacements, deformations and interstitial overpressures recorded during the seismic solicitation. It has been shown that numerical simulation is able to highlight the fundamental aspects of the displacements and deformations processes experienced by the structure ofdam and to produce preliminary results for the evaluation of the seismic behaviour of the structure taking into account the physical non-linearity of the materials constituting the body of the dam and the effect of the rigidity of the different zones of the dam and the foundation

Rubbery electronics and sensors from intrinsically stretchable elastomeric composites of semiconductors and conductors

A general strategy to impart mechanical stretchability to stretchable electronics involves engineering materials into special architectures to accommodate or eliminate the mechanical strain in nonstretchable electronic materials while stretched. We introduce an all solution-processed type of electronics and sensors that are rubbery and intrinsically stretchable as an outcome from all the elastomeric materials in percolated composite formats with P3HT-NFs [poly(3-hexylthiophene-2,5-diyl) nanofibrils] and AuNP-AgNW (Au nanoparticles with conformally coated silver nanowires) in PDMS (polydimethylsiloxane). The fabricated thin-film transistors retain their electrical performances by more than 55% upon 50% stretching and exhibit one of the highest P3HT-based field-effect mobilities of 1.4 cm2/V.s, owing to crystallinity improvement. Rubbery sensors, which include strain, pressure, and temperature sensors, show reliable sensing capabilities and are exploited as smart skins that enable gesture translation for sign language alphabet and haptic sensing for robotics to illustrate one of the applications of the sensors

Integer polyhedra for program analysis

Polyhedra are widely used in model checking and abstract interpretation. Polyhedral analysis is effective when the relationships between variables are linear, but suffers from imprecision when it is necessary to take into account the integrality of the represented space. Imprecision also arises when non-linear constraints occur. Moreover, in terms of tractability, even a space defined by linear constraints can become unmanageable owing to the excessive number of inequalities. Thus it is useful to identify those inequalities whose omission has least impact on the represented space. This paper shows how these issues can be addressed in a novel way by growing the integer hull of the space and approximating the number of integral points within a bounded polyhedron

Mesurer la vulnérabilité à la dégradation des conditions de travail dans les pays européens

Document de travail, n° 193Conformément aux objectifs européens d’une croissance et d’un marché du travail plus inclusifs, la question de la vulnérabilité des travailleurs occupe un pan essentiel de la politique économique et sociale européenne. Ce travail s’insère ainsi dans une réflexion visant à définir et à mesurer les différentes formes de vulnérabilité qui peuvent survenir et se développer dans le travail en Europe. Il propose un cadre conceptuel et méthodologique où la vulnérabilité est définie comme le degré d’exposition des travailleurs à des risques cumulés sur le lieu de travail, ayant des effets néfastes pour le bien-être et la santé. À cette fin, un indicateur de mauvaises conditions de travail est proposé : il agrège des facteurs relatifs aussi bien à l’environnement ‒ qu’il soit physique ou social ‒ qu’au contenu et à l’organisation du travail (forte intensité du travail, faible complexité, horaires atypiques). Cet indicateur synthétique est ensuite utilisé pour calculer la probabilité pour un travailleur d’être exposé à une dégradation de ses conditions de travail. C’est cette probabilité qui mesure la vulnérabilité aux conditions de travail dégradées. La mesure est construite à partir des données provenant des cinq dernières éditions de l’enquête européenne sur les conditions de travail (EWCS). S’appuyant sur les techniques d’estimation en pseudo-panel, les résultats montrent de grandes disparités de la vulnérabilité des travailleurs occupés au sein des quinze pays fondateurs de l’Union européenne. Les travailleurs de trois pays, la Grèce, l’Espagne et la France, apparaissent comme les plus exposés à la dégradation de leurs conditions de travail. Dans le cas particulier de la France, les résultats montrent une dégradation lente mais persistante des conditions de travail, engendrant ainsi une vulnérabilité face aux risques liés au travail supérieure à la médiane européenne..