A neural network-based inversion method of a feedback linearization controller applied to a hydraulic actuator

In this work, we use a neural network as a substitute for the traditional analytic functions employed as an inversion set in feedback linearization control algorithms applied to hydraulic actuators. Although very efective and with strong stability guarantees, feedback linearization control depends on parameters that are difcult to determine, requiring large amounts of experimental efort to be identifed accurately. On the other hands, neural networks require little efort regarding parameter identifcation, but pose signifcant hindrances to the development of solid stability analyses and/or to the processing capabilities of the control hardware. Here, we combine these techniques to control the positioning of a hydraulic actuator, without requiring extensive identifcation procedures nor losing stability guarantees for the closed-loop system, at reasonable computing demands. The efectiveness of the proposed method is verifed both theoretically and by means of experimental results

Investigating the toxicity of tropical reservoir sediments using the Allium test

Water pollution is a global environmental issue, and aquatic sediments are important compartments that might act as sinks or sources of contaminants. Once in the environment, inorganic contaminants such as metals can cause cytogenotoxic effects that damage genetic material and harm the aquatic community. Biological assays such as the Allium test can be used to investigate potential cytogenotoxicity of contaminated sediments based on the alterations of cell cycle indexes and chromosomal aberration frequencies. Therefore, we aimed to assess the toxicity of sediments from four Brazilian reservoirs using the Allium test. Sediments were sampled and elutriates were prepared in a simulating sediment resuspension in the water column. The Allium test was applied to the elutriates, and the metals copper, chromium, cadmium, lead, zinc, and iron were quantified. The elutriates derived from reservoir sediments were able to reduce the mitotic and anaphase index, increase the prophase and metaphase index, and boost chromosomal aberrations compared to the negative control. The cytogenotoxic effects observed may be linked to the presence of copper, zinc, and iron. Therefore, our results showed that the Allium test was a sensitive tool for warning the occurrence of genotoxic contaminants in sediment elutriates from four Brazilian reservoirs

Uma coleção de história em um museu de ciências naturais: o Museu Paulista de Hermann von Ihering

Instalado em um edifício-Monumento, data de 1895 a inauguração do Museu Paulista. Seu primeiro diretor, o zoólogo Hermann Von Ihering (1895-1916), teve a tarefa de organizar suas vastas coleções, as quais possuíam objetos de diversos ramos do conhecimento, entre eles, a História. Este artigo tem a intenção de entender a dimensão, dinâmica e concepção desta coleção de História, que recebeu pouca atenção da Historiografia relativa ao tema.The Museu Paulista, installed in a landmark building, was inaugurated in 1895. Its first director, the zoologist Herman von Ihering (1895-1916) undertook the assignment of organizing its extensive collections, which comprehended objects pertaining to varied fields of knowledge, including that of History. The present article aims at understanding the dimension, the dynamics and the conception of this historical collection. Until now little attention has been bestowed upon this subject matter by the specialized historiography

Aversão à desigualdade e preferências por redistribuição: A percepção de mobilidade econômica as afeta no Brasil?

Resumo A noção de que a redistribuição é dos ricos para os pobres permitiria concluir a priori que os pobres são os principais partidários de medidas redistributivas, ao serem os potenciais beneficiários. Não obstante, estudos realizados principalmente para países desenvolvidos sugerem que a aversão à desigualdade e as preferências por redistribuição são moldadas por fatores que vão além do pecuniário. Neste trabalho, analisa-se o efeito da mobilidade econômica subjetiva na aversão à desigualdade e na demanda por redistribuição dos brasileiros, usando-se uma base de dados única, representativa do país, coletada em 2012. Os resultados sugerem que, em contradição com previsões teóricas e com evidências de países desenvolvidos, mesmo pessoas que aspiram ascender socialmente no futuro incomodam-se com a desigualdade e são favoráveis a políticas redistributivas. Brasileiros que perceberam uma piora na sua situação econômica também mostram-se favoráveis à redistribuição, resultado mais convencional. Ambos os conjuntos de resultados são confirmados por estimações feitas em subamostras definidas por renda familiar. Levantam-se hipóteses para se tentar explicar os resultados inesperados

De uma "cientificidade difusa": o coronel e as práticas colecionistas do Museu Sertório na São Paulo em fins do século XIX

This article intends to examine the collecting practices of the private collection known as Museu Sertório, which became Museu Paulista's first main collection. For that, a brief biography of Colonel Joaquim Sertório, the owner of the Museum, will be presented, as well as aspects of the collections' organization, in order to reflect on Sertório's supposed dilettantism in scientific fields, since the museum was associated with an educational project of the period. A parallel between Museu Sertório and the Ashmolean Museum of Art and Archaelogy, of Oxford University, will also be made, in order to better understand its insertion in nineteenth-century São Paulo.Este artigo pretende examinar as práticas colecionistas realizadas em torno do Museu Sertório, uma coleção particular que veio a constituir o primeiro núcleo do acervo do Museu Paulista. Para tanto, serão apresentados alguns dados biográficos inéditos sobre o proprietário do Museu, o coronel Joaquim Sertório, bem como aspectos da organização das coleções, buscando, assim, refletir sobre o suposto amadorismo de Sertório no campo das ciências, uma vez que a abertura do acervo à visitação pública estava associada à intenção de vincular o museu a fins educativos. Procura-se, igualmente, traçar um paralelo entre a trajetória do Museu Sertório com a do Ashmolean Museum of Art and Archaelogy da Universidade de Oxford, Inglaterra, a fim de melhor compreender a sua inserção na São Paulo de fins do século XIX

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV