279 research outputs found

    Economie politique de la réforme de transition fiscale : le cas du Maroc

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    L'objet de cet article est de mettre en évidence le rôle crucial dans les réformes des facteurs d'économie politique très souvent négligés dans les pays en développement mais qui, ces dernières années, ont constitué un obstacle très important aux réformes de transition fiscale. Les auteurs ont considéré le cas du Maroc. Dans ce pays, les autorités utilisent de nombreux instruments pour agir sur des facteurs d'économie politique et créer un climat favorable à un programme ambitieux de réforme fiscale. Des constats de cette analyse peuvent certainement être tirées des leçons utiles pour les nombreux pays en développement s'engageant dans des réformes similaires

    A dynamical approach to generate chaos in a micromechanical resonator

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    Chaotic systems, presenting complex and non-reproducible dynamics, may be found in nature from the interaction between planets to the evolution of the weather, but can also be tailored using current technologies for advanced signal processing. However, the realization of chaotic signal generators remains challenging, due to the involved dynamics of the underlying physics. In this paper, we experimentally and numerically present a disruptive approach to generate a chaotic signal from a micromechanical resonator. This technique overcomes the long-established complexity of controlling the buckling in micro/nano-mechanical structures by modulating either the amplitude or the frequency of the driving force applied to the resonator in the nonlinear regime. The experimental characteristic parameters of the chaotic regime, namely the Poincar\'e sections and Lyapunov exponents, are directly comparable to simulations for different configurations. These results confirm that this dynamical approach is transposable to any kind of micro/nano-mechanical resonators, from accelerometers to microphones. We demonstrate a direct application exploiting the mixing properties of the chaotic regime by transforming an off-the-shelf microdiaphragm into a true random number generator conformed to the National Institute of Standards and Technology specifications. The versatility of this original method opens new paths to combine chaos' unique properties with microstructures' exceptional sensitivity leading to emergent microsystems

    Economie politique de la réforme de transition fiscale : le cas du Maroc

    Get PDF
    L'objet de cet article est de mettre en évidence le rôle crucial dans les réformes des facteurs d'économie politique très souvent négligés dans les pays en développement mais qui, ces dernières années, ont constitué un obstacle très important aux réformes de transition fiscale. Les auteurs ont considéré le cas du Maroc. Dans ce pays, les autorités utilisent de nombreux instruments pour agir sur des facteurs d'économie politique et créer un climat favorable à un programme ambitieux de réforme fiscale. Des constats de cette analyse peuvent certainement être tirées des leçons utiles pour les nombreux pays en développement s'engageant dans des réformes similaires.cerdi

    Economie politique de la réforme de transition fiscale : le cas du Maroc

    Get PDF
    L’objet de cet article est de mettre en évidence le rôle crucial dans les réformes des facteurs d’économie politique très souvent négligés dans les pays en développement mais qui, ces dernières années, ont constitué un obstacle très important aux réformes de transition fiscale. Les auteurs ont considéré le cas du Maroc. Dans ce pays, les autorités utilisent de nombreux instruments pour agir sur des facteurs d’économie politique et créer un climat favorable à un programme ambitieux de réforme fiscale. Des constats de cette analyse peuvent certainement être tirées des leçons utiles pour les nombreux pays en développement s’engageant dans des réformes similaires.

    Nîmes – Introduction

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    Inventeur(s) : Compan Michel ; Hervé Marie-Laure (AFAN) ; Veyrac Alain ; Pène Jean-Michel Une archéologie de la ville et des campagnes La commune de Nîmes (Gard) intègre, du nord vers le sud, des unités géographiques distinctes : la zone des Garrigues qui s'achève, au contact de la ville antique, par une série de collines de faible altitude dessinant une sorte de théâtre naturel, un piémont qui descend en pente douce vers le sud-est, sur une emprise de 1 à 2 km, la plaine alluviale du Vistre,..

    Solar irradiances measured using SPN1 radiometers: uncertainties and clues for development

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    International audienceThe fast development of solar radiation and energy applications, such as photovoltaic and solar thermodynamic systems, has increased the need for solar radiation measure-ment and monitoring, for not only the global but also the diffuse and direct components. End users look for the best compromise between getting close to state-of-the-art mea-surements and keeping low capital, maintenance and operat-ing costs. Among the existing commercial options, SPN1 is a relatively low cost solar radiometer that estimates global and diffuse solar irradiances from seven thermopile sensors under a shading mask and without moving parts. This work presents a comprehensive study of SPN1 accu-racy and sources of uncertainty, drawing on laboratory ex-periments, numerical modelling and comparison studies be-tween measurements from this sensor and state-of-the art in-struments for six diverse sites. Several clues are provided for improving the SPN1 accuracy and agreement with state-of-the art measurements

    Influence of the cassava harvest month on the sensory parameters of attiéké

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    Cassava is an important staple food around the world, especially in Africa. It is cultivated throughout the Ivorian territory with predominance in the South. Due to the high demand, some producers opt for an early harvest, neglecting the impact of the harvest stage on the sensory parameters of cassava root derivatives. The objective of this work was to determine the stage of harvest allowing obtaining products of good sensory quality. The sensory characteristics of the attiéké were evaluated at different stages of harvest (11th, 12th, 13th and 14th months after planting the cuttings) of the cassava roots of the Yacé variety which were used for its production. The attiéké obtained in the twelfth month of harvest was generally much appreciated because it was less acidic, less fibrous and more homogeneous and had a better smell. Thus, cassava harvested in the twelfth month of cultivation makes it possible to obtain attiéké with the best sensory characteristics. Therefore, this stage of maturity of cassava roots is recommended for attiéké producers

    The adoption of open access scholarly communication in Tanzanian public universities: some Influencing factors

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    Open access is a means for free availability of scholarly content via the internet. It is an emerging opportunity for wider and unlimited access to scholarly literature. Scholarly communication, through open access journals and self-arching, are the two main approaches of open access publishing. However, this mode of scholarly communication is not widely utilised in developing countries such as Tanzania. This article discusses the factors that influence the adoption of open access for scholarly communication in Tanzanian public universities, based on a study conducted in 2008 using a survey questionnaire. A sample of 544 researchers, selected through stratified random sampling from a population of 1 088 researchers and 69 policymakers at six public universities in Tanzania, provided their views. It was evident from the findings that researchers’ internet usage skills and self-efficacy, social influence, performance expectancy, effort expectancy, and the respondents’ general perceptions about open access were the positive factors likely to facilitate open access adoption. The current poor research conditions and researchers’ low internet self-efficacy (such as inadequate information search skills) were cited as the main hindrances for researchers to use open access outlets to access scholarly content. It is therefore recommended that university policies on scholarly communication should be revised to incorporate the use of open access publishing. Furthermore, universities should accelerate the establishment of institutional repositories, advocacy campaigns and training directed at researchers, policymakers, readers and information managers of scholarly content, and the improvement of internet speed through subscription to more bandwidth, so as to meet the demand from the scholarly communit

    Hepatitis C Virus Infection in Guinea-Bissau: A Sexually Transmitted Genotype 2 with Parenteral Amplification?

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    BACKGROUND: Sub-Saharan Africa is the continent with the highest prevalence of Hepatitis C virus (HCV) infection. Genotype 2 HCV is thought to have originated from West Africa several hundred years ago. Mechanisms of transmission remain poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: To delineate mechanisms for HCV transmission in West Africa, we conducted a cross-sectional survey of individuals aged ≥50 years in Bissau, Guinea-Bissau. Dried blood spots were obtained for HCV serology and PCR amplification. Prevalence of HCV was 4.4% (47/1066) among women and 5.0% (27/544) among men. In multivariate analysis, the independent risk factors for HCV infection were age (baseline: 50–59 y; 60–69 y, adjusted odds ratio [AOR]: 1.67, 95% CI: 0.91–3.06; ≥70 y, AOR: 3.47, 95% CI: 1.89–6.39), belonging to the Papel, Mancanha, Balanta or Mandjako ethnic groups (AOR: 2.45, 95% CI:1.32–4.53), originating from the Biombo, Cacheu or Oio regions north of Bissau (AOR: 4.16, 95% CI: 1.18–14.73) and having bought or sold sexual services (AOR: 3.60, 95% CI: 1.88–6.89). Of 57 isolates that could be genotyped, 56 were genotype 2. CONCLUSIONS: Our results suggest that transmission of HCV genotype 2 in West Africa occurs through sexual intercourse. In specific locations and subpopulations, medical interventions may have amplified transmission parenterally
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