Nature et fonction du secteur informel : une analyse de la satisfaction dans l'emploi au Vietnam

Document de travail en ligne: DIAL DT/2012/10,32 p

Institutions, gouvernance et croissance à long terme à Madagascar : l'énigme et le paradoxe

Les théories classiques et récentes du développement sont impuissantes à expliquer la contreperformance économique malgache sur longue période. Cet article propose une relecture de l'histoire malgache en mobilisant le cadre d’analyse de l’économie politique. Nos analyses pointent qu’en dépit de facteurs de blocage profonds, Madagascar a fait montre d'une capacité de transformation d'une modernité inattendue : transitions économique (avec l'arrivée d'une classe d'entrepreneurs nouveaux) et politique (avec les alternances démocratiques) ; mise en place d'institutions solides caractéristiques des sociétés « modernes » ; contrôle de la violence ; expression des aspirations économiques et citoyennes de la population. Trois entraves structurelles s’opposent en revanche au développement du pays : la fragmentation de la société, l'atomisation de la population et l'atrophie des corps intermédiaires favorisent une forte concentration du pouvoir aux mains d'une poignée d'élites qui n'est ni contrainte ni incitée à avoir une vision de moyen/long terme et à prendre en compte les intérêts de la grande majorité ; malgré sa revendication des principes démocratiques, la population reste tiraillée entre des revendications citoyennes de type démocratique et méritocratique et des valeurs traditionnelles qui imposent le respect de hiérarchies réelles et symboliques héritées du passé ; enfin, les politiques promues, voire imposées, par les bailleurs de fonds, si elles ont pu avoir des effets positifs, ont également eu un impact négatif majeur sur la capacité de l'Etat à réguler la société

Comparative Genomics Analysis of Streptococcus tigurinus Strains Identifies Genetic Elements Specifically and Uniquely Present in Highly Virulent Strains.

Streptococcus tigurinus is responsible for severe invasive infections such as infective endocarditis, spondylodiscitis and meningitis. As described, S. tigurinus isolates AZ_3aT and AZ_14 were highly virulent (HV phenotype) in an experimental model of infective endocarditis and showed enhanced adherence and invasion of human endothelial cells when compared to low virulent S. tigurinus isolate AZ_8 (LV phenotype). Here, we sought whether genetic determinants could explain the higher virulence of AZ_3aT and AZ_14 isolates. Several genetic determinants specific to the HV strains were identified through extensive comparative genomics amongst which some were thought to be highly relevant for the observed HV phenotype. These included i) an iron uptake and metabolism operon, ii) an ascorbate assimilation operon, iii) a newly acquired PI-2-like pilus islets described for the first time in S. tigurinus, iv) a hyaluronate metabolism operon, v) an Entner-Doudoroff pathway of carbohydrates metabolism, and vi) an alternate pathways for indole biosynthesis. We believe that the identified genomic features could largely explain the phenotype of high infectivity of the two HV S. tigurinus strains. Indeed, these features include determinants that could be involved at different stages of the disease such as survival of S. tigurinus in blood (iron uptake and ascorbate metabolism operons), initial attachment of bacterial pathogen to the damaged cardiac tissue and/or vegetation that formed on site (PI-2-like pilus islets), tissue invasion (hyaluronate operon and Entner-Doudoroff pathway) and regulation of pathogenicity (indole biosynthesis pathway)

The effect of temperature and bulk composition on the solution mechanism of phosphorus in peraluminous haplogranitic magma.

Solution mechanisms of P in peraluminous glasses and melts in the system CaO-Na2O-K2O-Al2O3- SiO2-P2O5 have been examined with in-situ microRaman spectroscopy from ambient temperature to near 1200 °C. The principal aim was to examine the relative stabilities of phosphate complexes as functions of P content, peraluminosity, and temperature. Increasing peraluminosity was accomplished by increasing the proportions of Al3+ and Ca2+ of constant SiO2 content. The molar ratio Al2O3/ (CaO+Na2O+K2O) (A/CNK) ranged from ~1 to ~1.3. In all compositions, P5+ is bonded to Al3+ to form AlPO4 complexes. In addition, there is evidence for pyrophosphate complexing (P2O7). In melts with the highest (Ca+Na+K)/P, there is probably also a small fraction of orthophosphate complexes present. The relative importance of AlPO4-like complexes is correlated positively with peraluminosity (A/CNK), P2O5 content, and increasing temperature at temperatures above that of the glass transition. These structural relationships among phosphate complexes are coupled with decreasing polymerization of the aluminosilicate melts

Probabilistic ballistic annihilation with continuous velocity distributions

We investigate the problem of ballistically controlled reactions where particles either annihilate upon collision with probability $p$, or undergo an elastic shock with probability $1-p$. Restricting to homogeneous systems, we provide in the scaling regime that emerges in the long time limit, analytical expressions for the exponents describing the time decay of the density and the root-mean-square velocity, as continuous functions of the probability $p$ and of a parameter related to the dissipation of energy. We work at the level of molecular chaos (non-linear Boltzmann equation), and using a systematic Sonine polynomials expansion of the velocity distribution, we obtain in arbitrary dimension the first non-Gaussian correction and the corresponding expressions for the decay exponents. We implement Monte-Carlo simulations in two dimensions, that are in excellent agreement with our analytical predictions. For $p<1$, numerical simulations lead to conjecture that unlike for pure annihilation ($p=1$), the velocity distribution becomes universal, i.e. does not depend on the initial conditions.Comment: 10 pages, 9 eps figures include

Manifestations de la sécheresse en Afrique de l'Ouest non sahélienne : cas de la Côte d'Ivoire, du Togo et du Bénin

La sécheresse qui sévit depuis une vingtaine d'années dans les régions sahéliennes d'Afrique de l'Ouest semble avoir des manifestations également plus au sud dans les pays riverains du golfe de Guinée. Une double analyse, ponctuelle et spatialisée, concernant les précipitations annuelles de la Côte d'Ivoire, du Togo et du Bénin permet de mettre ce fait en évidence. Les séries chronologiques d'indices pluviométriques confirment la chute brutale de la pluviométrie à la fin des années 60. La représentation cartographique des résultats montre le net glissement des courbes isohyètes vers le sud et permet de prendre en compte la dimension régionale du phénomène. (Résumé d'auteur

Infusion of herbal plant extracts for insomnia and anxiety causes a dose-dependent increase of NO and has a protective effect on the renal cellular stress caused by hypoxia and reoxygenation

Background: Herbal plant extracts are a more common alternative to conventional medicine to treat sleep disorders and intermittent hypoxia. Notably, obstructive sleep apnea causes injuries similar to those observed in models of ischemia-reperfusion including the decrease of nitric oxide (NO) availability. Kidney transplantation in end-stage renal disease reverses the sleep apnea. The underlying mechanism linking hypoxia, sleep apnea, and renal protection remains to be defined at the cellularlevel.Objective: The aim of this study was to demonstrate the safety and efficacy of herbal plant infusions with a potential for donating NO, to attenuation of damage induced during a hypoxia/reperfusion sequence, on kidney epithelial cells LLC-PK1.Materials and Methods: Cell death (Lactate Dehydrogenase release assay) and a viability test (MTS assay) after 24 h of incubation with different concentrations of plant infusion were assessed using the LLC-PK1 cell line. Then, measurement of the breakdown product of NO (the NaNO2) and LDH assay were carried out after 24 h of hypoxia, followed by 4 h or 24 h of reperfusion.Results: The effect of different dilutions of herbal plant infusion on the LLC-PK1 cell viability, after 24 h of incubation, wasmaximal at a 30% dilution compared to control. After 24 h of hypoxia, there was an increase of NaNO2 and thus of NO, and a concentration-dependent decrease of cell death. Similar results were observed after hypoxia followed by 4 h of reperfusion. These effects were always maximal at 50% dilution of plants infusion.Conclusion: Safe infusion of plant extracts causes a dose-dependent increase of NO and has a protective effect against the cellular stress caused by hypoxia and reoxygenation. Since it has been demonstrated that there is a NO-dependent mechanism allowing the reduction of injuries induced by ischemia/reoxygenation process, such a mechanism could be responsible for our observations

Les étapes d’une expérience en économie expérimentale

This document applies to anybody who wants to understand what is Experimental Economics and the benefits that can profit from this approach for empirical works which validity and scope can be evaluated in a scientific work. In a pragmatic way are described in this document the different steps to be followed methodologically to set out an experiment. Our goal is to give our readers a broad view of an experimental process in economics. Further to the logistics aspects and data collection, this guide also tackles the tools used to work with data and the methodological referees that allow analysing the first results. It also reviews various animation support of the experimentalist community in France