704 research outputs found

    Identification and estimation of interventions using changes in inequality measures

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    This paper presents semiparametric estimators of changes in inequality measures of adependent variable distribution taking into account the possible changes on the distribu-tions of covariates. When we do not impose parametric assumptions on the conditionaldistribution of the dependent variable given covariates, this problem becomes equivalent toestimation of distributional impacts of interventions (treatment) when selection to the pro-gram is based on observable characteristics. The distributional impacts of a treatment willbe calculated as di¤erences in inequality measures of the potential outcomes of receivingand not receiving the treatment. These differences are called here Inequality TreatmentEffects (ITE). The estimation procedure involves a first non-parametric step in whichthe probability of receiving treatment given covariates, the propensity-score, is estimated.Using the inverse probability weighting method to estimate parameters of the marginal dis-tribution of potential outcomes, in the second step weighted sample versions of inequalitymeasures are computed. Root-N consistency, asymptotic normality and semiparametrice¢ ciency are shown for the semiparametric estimators proposed. A Monte Carlo exerciseis performed to investigate the behavior in finite samples of the estimator derived in thepaper. We also apply our method to the evaluation of a job training program.

    Bounds on functionals of the distribution treatment effects

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    Bounds on the distribution function of the sum of two random variableswith known marginal distributions obtained by Makarov (1981) canbe used to bound the cumulative distribution function (c.d.f.) of individualtreatment effects. Identification of the distribution of individualtreatment effects is important for policy purposes if we are interested infunctionals of that distribution, such as the proportion of individuals whogain from the treatment and the expected gain from the treatment forthese individuals. Makarov bounds on the c.d.f. of the individual treatmenteffect distribution are pointwise sharp, i.e. they cannot be improvedin any single point of the distribution. We show that the Makarov boundsare not uniformly sharp. Specifically, we show that the Makarov boundson the region that contains the c.d.f. of the treatment effect distributionin two (or more) points can be improved, and we derive the smallest setfor the c.d.f. of the treatment effect distribution in two (or more) points.An implication is that the Makarov bounds on a functional of the c.d.f.of the individual treatment effect distribution are not best possible.

    The relationship between school violence and student proficiency

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    School violence has recently become a central concern among teachers, students, students' parents andpolicymakers. Violence can induce behaviors on educational agents that go against the goals ofimproving the quality of education and increasing school attendance. In fact, there is evidence thatschool environmental characteristics and student performance and behavior at school are related.Although school violence may have a direct impact on students’ performance, such impact has not yetbeen quantified. In this paper, we investigate this issue using Brazilian data and show that, on average,students who attended more violent schools had worse proficiency on a centralized test carried out bythe Brazilian Ministry of Education, even when we controlled for school, class, teachers and studentcharacteristics. We also show that school violence affects more the students from the bottom of theproficiency distribution. Furthermore, we find out that besides the direct effect on student proficiency,it seems that school violence has an indirect effect on it operating through teacher turnover. Indeed, weshow that the occurrence of violent episodes in a school decreases the probability of a class in thatschool having only one teacher during the academic year, and increases the probability of that classhaving more than one teacher (teacher turnover).

    Escolaridade e o diferencial de rendimentos entre o setor privado e o setor público no Brasil

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    We study the determinants of the public-private earning gap for differentlevels of schooling of Brazilian workers. First, using the current earnings as thevariable of interest, it is estimated an earnings gap favorable to the less educatedworkers from the public sector. On the other hand, for workers with higherqualification the earnings gap disappears or becomes favorable to the privatesector. Further, we considerate the different regimes of retirement in Brazil bycreating the variable Present Value of Work Contract (PVWC). This variable is ameasure of the life time earnings for each individual of our database. Differentfrom the results of the current earnings, we found that the PVWC gap is favorableto the public sector even for the most schooling group of workers.

    Angiotensin Converting Enzyme 2, Angiotensin-(1-7), and Receptor Mas Axis in the Kidney

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    In the past few years the understanding of the renin-angiotensin system (RAS) has improved, helping to better define the role of this system in physiological conditions and in human diseases. Besides Angiotensin (Ang) II, the biological importance of other Ang fragments was progressively evidenced. In this regard, Angiotensin- (Ang-) (1-7) was recognized as a biologically active product of the RAS cascade with a specific receptor, the G-protein-coupled receptor Mas, and that is mainly formed by the action of the angiotensin-converting enzyme (ACE) homolog enzyme, ACE2, which converts Ang II into Ang-(1-7). Taking into account the biological effects of these two mediators, Ang II and Ang-(1-7), the RAS can be envisioned as a dual function system in which the vasoconstrictor/proliferative or vasodilator/antiproliferative actions are primarily driven by the balance between Ang II and Ang-(1-7), respectively. In this paper, we will discuss our current understanding of the ACE2/Ang-(1-7)/Mas axis of the RAS in renal physiology and in the pathogenesis of primary hypertension and chronic kidney disease

    Módulo analógico para um conversor A/D por aproximações sucessivas

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    Trabalho de Conclusão Curso (graduação)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2018.Este trabalho apresenta o desenvolvimento dos módulos analógicos de um conversor analógico- digital por aproximações sucessivas de 10 bits construído em tecnologia CMOS 0.18 μm. Neste trabalho foi implementado um modelo comportamental do conversor em Matlab e a partir do algoritmo denido, partiu-se para o desenvolvimento do circuito analógico do conversor. O conversor foi concebido a partir de uma divisão do circuito em blocos funcionais. Dentre es- ses blocos destacam-se os circuitos sample and hold, comparador e conversor digital-analógico. Além da implementação completa da parte analógica do conversor, a sua validação foi feita através de uma análise e validação de cada bloco em separado. A validação do sistema com- pleto do conversor foi efetuada por simulação, sendo que todos os requisitos das especicações iniciais foram satisfeitos.This work presents the development of analog modules for a 10 bit successive approximation analog to digital converter, built in 0.18μm CMOS technology. In this work, a behavioral model of the converter was implemented in Matlab, and from the algorithm dened in the model, the converter analog circuit was developed. The converter was conceived from the division of the circuit in blocks. Among those blocks there are a sample and hold, a comparator and a digital to analog converter. Besides the complete implementation of the converter analog circuit, its validation was done by analysis and validation of each block separately. The validation of the entire converter was also realized by simulation, and all the initial specications were satised

    Análise estática não-linear geométrica de estruturas pelo método de superposição modal com base Lanczos-Ritz

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    The purpose of this work is to present the method of linear buckling mode superposition as a procedure for geometric nonlinear static analysis of slender structures, and to examine, as an alternative to a modal basis, the use of a coordinates transformation constitutes by vectors produced in a non-iterative way from a Lanczos algorithm. In the method of buckling mode superposition the eingenvectores have been tradionally used as basis vectors. The high computational cost of this procedure, caused by the iterative character of the eingenvalue problem, is its main drawback. The proposed method reduces the computer time requirements significantly without affecting the accuracy of the results. The viability of the proposed algorithm is investigated through some examples. Comparisons with the classical mode superposition method and a full nonlinear analysis are presented and the obtained results discussed.O objetivo deste trabalho é apresentar o método de superposição modal como um procedimento para a análise estática não linear geométrica de estruturas esbeltas, assim como, examinar o emprego de uma base de transformação de coordenadas constituída por vetores gerados de uma forma não iterativa a partir de um algoritmo do tipo Lanzos, como alternativa ao uso da base modal. No método de superposição modal tem sido tradicionalmente utilizado os autovetores como vetores base. Este procedimento tem como principal inconveniente o elevado custo computacional, devido ao caráter iterativo da solução do problema de autovalor. A adoção da base proposta reduz drasticamente este custo sem afetar a precisão dos resultados. A viabilidade do algoritmo proposto é investigada por meio de alguns exemplos, nos quais é comparado com o método de superposição modal clássico e com os métodos de análise não lineares do tipo Newton-Raphson

    As perspectivas da agricultura orgânica em Santa Catarina

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    Analysis of the production function in civil construction: a driver for lean construction

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    The construction industry has bleen an important role for economic growth, and gains in productivity could produce a significative impact. However, historically, it has been proved that this industry is operating not significativelly well in terms of efficiency related performance. The objective of this work is to justify the adoption of Lean Construction, as a comprehensive alternative for addressing problems related to resource and systemic productivity. To frame the productivity problem, the work analyzes the productivity of this sector, using the production function of Cobb Douglas, which is an econometric concept that provides information to assess relationships between the total volume produced, and the resources that are used during the production process. The present work has analyzed biggest  companies in the world of civil construction, all of them listed in the Forbes 2017 publication. The production function analysis shows that these organizations are experiencing returns of decreasing scale. To address this results, this paper discusses the use of lean construction as a feasible alternative to increase productivity, considering the effects that operations networks and supply chain level could produce in the aggregate level of industry performance
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