3,070 research outputs found

    An Illustration of the Returns to Training Programmes: The Evaluation of the “Qualifying Contract" in France

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    We evaluate the labour market outcomes of a French training programme for youth, using a non-experimental sample of individuals who completed their studies (or dropped out) in 1998 and were observed until 2003. We use propensity score matching to estimate the impact of participation on three outcome variables: the net monthly wage, the monthly income and the probability of employment. We find a positive impact of participation on all three outcome variables. Non parametric robustness checks confirmed our results. We explain these results, which contrast with those of previous French studies, by the very strong training content of the programme.active labour market programmes, training programmes for youth, propensity score matching

    Contact interaction in an unitary ultracold Fermi gas

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    An ultracold Fermi atomic gas at unitarity presents universal properties that in the diluted limit can be well described by a contact interaction. By employing a guide function with correct boundary conditions and making simple modifications to the sampling procedure we are able to handle for the first time a true contact interaction in a quantum Monte Carlo calculation. The results are obtained with small variances. Our calculations for the Bertsch and contact parameters are in excellent agreement with published experiments. The possibility of using a more faithfully description of ultracold atomic gases can help uncover features yet unknown of the ultracold atomic gases. In addition, this work paves the way to perform quantum Monte Carlo calculations for systems interacting with contact interactions, where in many cases the description using potentials with finite effective range might not be accurate

    Generalising the logistic map through the qq-product

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    We investigate a generalisation of the logistic map as xn+1=1axnqmapxn x_{n+1}=1-ax_{n}\otimes_{q_{map}} x_{n} (1xn1-1 \le x_{n} \le 1, 0<a20<a\le2) where q\otimes_q stands for a generalisation of the ordinary product, known as qq-product [Borges, E.P. Physica A {\bf 340}, 95 (2004)]. The usual product, and consequently the usual logistic map, is recovered in the limit q1q\to 1, The tent map is also a particular case for qmapq_{map}\to\infty. The generalisation of this (and others) algebraic operator has been widely used within nonextensive statistical mechanics context (see C. Tsallis, {\em Introduction to Nonextensive Statistical Mechanics}, Springer, NY, 2009). We focus the analysis for qmap>1q_{map}>1 at the edge of chaos, particularly at the first critical point aca_c, that depends on the value of qmapq_{map}. Bifurcation diagrams, sensitivity to initial conditions, fractal dimension and rate of entropy growth are evaluated at ac(qmap)a_c(q_{map}), and connections with nonextensive statistical mechanics are explored.Comment: 12 pages, 23 figures, Dynamics Days South America. To be published in Journal of Physics: Conference Series (JPCS - IOP

    Avaliação de genótipos de mandioca da reserva extrativista Cazumbá-Iracema, Acre.

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    A mandioca é o principal produto agrícola do Acre, cultivado para geração de renda e segurança alimentar, sendo tipicamente de exploração familiar. Este trabalho teve como objetivo avaliar genótipos de mandioca na Reserva Extrativista do Cazumbá-Iracema, localizada no município de Sena Madureira, AC. Foram instalados três experimentos nas localidades Cazumbá, Cuidado e Alto Caeté, utilizando-se o delineamento inteiramente casualizado com quatro repetições. Foram avaliados; número de raízes por planta, percentagem de amido e massa seca de raízes, produtividade e rendimento de farinha de mandioca. Foi realizada a avaliação de oito genótipos nas localidades de Cazumbá e Cuidado e de seis genótipos em Alto Caeté, analisando conjuntamente os quatro genótipos Panatí, Araçá, Colonial e Pirarucu que foram plantados nas três localidades. Os dados foram submetidos a análise de variância e para os efeitos significativos, aplicou-se o teste de Tukey e Scott-Knott a 5 % de probabilidade. A cultivar Pirarucu, que é a mais plantada na reserva, foi ogenótipo que apresentou melhor desempenho quanto a produtividade e rendimento de farinha

    Reemployment and substitution effects from increased activation: Evidence from times of crisis

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    Although activation services such as monitoring, training, or job subsidies have been shown to increase exits from unemployment, there is little comprehensive evidence about the effects of activation during recessions. Here we evaluate a large activation programme introduced in Portugal in 2012, a time of very high unemployment. This programme required specific unemployment benefit recipients to meet jobcentre caseworkers and then participate in active labour market policies. Our analysis draws on rich longitudinal data, the programme’s focus on those unemployed for at least six months, and fuzzy regression discontinuity methods. We find that, despite the weak labour market, the programme is very successful as it doubles the monthly reemployment probability. The results are robust to a number of checks, including a falsification exercise based on pre-programme data and an analysis of non-employment and income effects. Moreover, in a novel IV approach using information on all unemployed, we find no evidence of substitution effects such as decreased transitions to employment amongst non-eligible individuals.N/

    Silicon Carbide as Base Material for MEMS Sensors of Aerospace Use: An Overview

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    This paper discusses the use of silicon carbide (SiC), in bulk and thin-film form, in MEMS (Micro-Electro-Mechanical Systems) sensors for extreme environment applications, especially in aerospace. The physical and chemical properties of SiC that make it a suitable material for electronic devices and sensors are described. Concepts, developments and applications of MEMS technology are presented. An overview of the current stage of development of SiC-based MEMS sensors and an analysis of research conducted in this area in Brazil and abroad, both in universities and industries are also presented. The recent progress made, difficulties encountered and the impact of these investigations are discussed as well as the outlook for the near future.Este artigo discute o emprego do carbeto de silício (SiC), na forma de substrato e filme fino, em sensores MEMS (Micro-Electro-Mechanical Systems) para aplicações em ambientes sujeitos a condições extremas, especialmente no setor aeroespacial. As propriedades físicas e químicas do SiC que o tornam um material adequado para dispositivos eletrônicos e sensores são descritas. Os conceitos, evolução e aplicações da tecnologia MEMS são apresentados. Uma visão geral sobre o estágio atual de desenvolvimento de sensores MEMS baseados em SiC e uma análise das pesquisas realizadas nesta área no exterior e no Brasil, tanto nas universidades quanto nas indústrias, são também apresentadas. Os recentes avanços alcançados, as dificuldades encontradas e o impacto dessas pesquisas são discutidos, bem como as perspectivas para um futuro próximo.FATEC CEETEPS Departamento de Ensino GeralUNIVAP Instituto de Pesquisa e DesenvolvimentoUNIFESP Instituto de Ciência e TecnologiaUNIFESP, Instituto de Ciência e TecnologiaSciEL

    La historia de la ciencia como herramienta para la enseñanza de física en secundaria : un ejemplo en calor y temperatura

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    In this work we suggest and analyze some stages of a course on heat and temperature which knowledge of the past of the ideas and the solution provided can enable a better understanding of the content. The hypothesis that guided the planning of activities was that the scientific content studied throughout its history comes closer to the cognitive universe, not only of the student, but of man himself
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