Charge sparsity: An index to quantify cation effects on clay dispersion in soils

Few approaches have been developed to measure the isolated effect of exchangeable cations on clay dispersion in soils. In this study, the charge sparsity (CS) index was proposed using the ratio between the cations hydrated ionic radius and valence. The index capacity to measure cation effects on clay dispersion in soils was also evaluated. Three Ferralsols, sampled at different sites in Paraná State, Brazil, were homoionized with Ca2+, Mg2+, K+, or Na+ prior to evaluation of the clay dispersion degree. Published independent data for two soils and clays were also used. We tested the capacity of CS and II, the latter proposed by Marchuck and Rengasamy (2011), to predict clay dispersion in soils. The CS predicted the dispersion degree more accuratelly than the ionicity index did, in soils where Ca2+ and Mg2+ behaved similarly. The response of Paraná soils to CS varied with soil characteristics. Soils with a lower pH at the isoelectric point were more dispersible by cations with high CS (K+ and Na+). The CS was efficient to quantify the isolated effect of cations on the clay dispersion process in soils. Therefore, qualitative and quantitative studies can benefit from the CS as an index to understand the effect of cations on clay dispersion in soils

DIFICULDADES DA APRENDIZAGEM DA MATEMÁTICA DURANTE DESENVOLVIMENTO INFANTIL

A qualidade da educação pode ser questionada, com base em constatações de que boa parte dos alunos não apresentam, com a matemática, um bom desenvolvimento cognitivo esperado ao final do ensino fundamental, em uma capital nordestina. Isso pode ser devido a processos falhos de ensino, ao começar pelos pais e firmar-se nas escolas, onde geralmente, nas séries iniciais não há um modelo adequado que impulsione a criança a desenvolver a percepção e o raciocínio como poderia ser. Modelos educacionais antigos e métodos um tanto que ineficientes, podem, comumente, desconsiderar matérias como teatro e educação artística, apesar da grande importância no desenvolvimento cognitivo, ao ponto de impactar nas reflexões desta pesquisa

A heuristic algorithm for nurse scheduling with balanced preference satisfaction

This paper tackles the nurse scheduling problem with balanced preference satisfaction which consists of generating an assignment of shifts to nurses over a given time horizon and ensuring that the satisfaction of nurses personal preferences for shifts is as even as possible in order to ensure fairness. We propose a heuristic algorithm based on successive resolutions of the bottleneck assignment problem. The algorithm has two phases. In the first phase, the algorithm constructs an initial solution by solving successive bottleneck assignment problems. In the second phase, two improvement procedures based on reassignment steps are applied. Computational tests are carried out using instances from the standard benchmark dataset NSPLib. Our experiments indicate that the proposed method is effective and efficient, reducing discrepancies (hence improving fairness) between the individual rosters

A heuristic algorithm for nurse scheduling with balanced preference satisfaction

This paper tackles the nurse scheduling problem with balanced preference satisfaction which consists of generating an assignment of shifts to nurses over a given time horizon and ensuring that the satisfaction of nurses personal preferences for shifts is as even as possible in order to ensure fairness. We propose a heuristic algorithm based on successive resolutions of the bottleneck assignment problem. The algorithm has two phases. In the first phase, the algorithm constructs an initial solution by solving successive bottleneck assignment problems. In the second phase, two improvement procedures based on reassignment steps are applied. Computational tests are carried out using instances from the standard benchmark dataset NSPLib. Our experiments indicate that the proposed method is effective and efficient, reducing discrepancies (hence improving fairness) between the individual rosters

Teoria da reprodução social, educação escolar quilombola e desigualdades socioeducacionais

Este estudo tem o objetivo de discutir a Educação Escolar Quilombola – EEQ, como ela se constituiu por meio de políticas públicas educacionais voltadas para a população remanescente de quilombos em todo território nacional. Grupo esse que sempre esteve à margem da sociedade e dos bens por ela produzidos. Para compreender os processos de luta do movimento quilombola e como a EEQ se constituiu enquanto política nos apoiamos nas discussões de Larchert e Oliveira (2013), além de documentos oficias do estado brasileiro. Buscou-se analisar esta modalidade da Educação Básica à luz da Teoria da Reprodução Social surgida na segunda metade do século XX. Para tanto, mobilizamos autores, como Bourdieu (2007) Bourdieu e Passeron (2014) e Nogueira (2021) com os conceitos de Capital Cultural, Social e Econômico e Bernstein (2003) utilizando a discussão em torno do conceito de recontextualização. E por fim, efetuamos um diálogo entre a EEQ e o referencial teórico escolhido para compreender como a escola, o currículo e seus discursos têm contribuído para a reprodução social e, consequentemente, transformar desigualdades sociais em desigualdades educacionais. Destacamos que esta reflexão faz parte de um recorte teórico realizado na pesquisa de doutoramento em educação que está em andamento no Programa de Pós-Graduação em Educação da Universidade Federal de Ouro Preto. "O presente trabalho foi realizado com apoio da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Código de Financiamento 001”.This work aims to discuss Quilombola School Education - EEQ, as it was constituted as a public educational policy aimed at the remaining population of quilombos throughout the national territory. This group has always been on the margins of society and the goods produced by it. To understand the struggle processes of the quilombola movement and how the EEQ was constituted as a policy, we rely on the discussions of Larchert and Oliveira (2013), as well as official documents from the Brazilian state. We sought to analyze this modality of Basic Education in the light of the Theory of Social Reproduction that emerged in the second half of the 20th century. To this end, we mobilize authors such as Bourdieu (2007) Bourdieu and Passeron (2014) and Nogueira (2021) with the concepts of Cultural, Social and Economic Capital and Bernstein (2003) using the discussion around the concept of recontextualization. Finally, we carried out a dialogue between the EEQ and the theoretical framework chosen to understand how the school, the curriculum and its discourses have contributed to social reproduction and, consequently, to transform social inequalities into educational inequalities. We emphasize that this reflection is part of a theoretical approach carried out in the doctoral research in education that is in progress at the Graduate Program in Education at the Federal University of Ouro Preto. "The present work was carried out with the support of the Coordination for the Improvement of Higher Education Personnel - Brazil (CAPES) - Financing Code 001"

Clay dispersion and loss in Oxisol treated with different concentrations of limestone

The addition of limestone to the soil may cause clay dispersion and loss. In this study, we aimed to estimate clay dispersion and loss in Oxisol incubated with different concentrations of limestone. To this end, soil samples were collected from a depth of 0.0-0.20 m, treated with limestone at a concentration of 1.46 Mg ha-1 or 2.73 Mg ha-1 to raise base saturation to 60% and 70%, respectively, and incubated for 12 months under greenhouse conditions. Clay dispersion analysis was conducted monthly using the test tube method. The results showed that clay dispersion increased with soil pH and time after limestone application. However, no significant change in clay concentration was identified in the control (no limestone application). At 60% base saturation, clay loss was first observed to be significantly higher than that of the control at 4 months after application and reached a maximum at 9 months after application. At 70% base saturation, clay loss was also first observed to be significantly higher than that of the control at 4 months after application and reached a maximum at 6 months after application. Overall, our data revealed that clay dispersion due to limestone application was approximately 16 g kg-1 over a period of 12 months and increased with the increasing concentrations of Ca and Mg

A heuristic algorithm based on multiassignment procedures for nurse scheduling

This paper tackles a Nurse Scheduling Problem which consists of generating work schedules for a set of nurses while considering their shift preferences and other requirements. The objective is to maximize the satisfaction of nurses? preferences and minimize the violation of soft constraints. This paper presents a new deterministic heuristic algorithm, called MAPA (multi-assignment problem-based algorithm), which is based on successive resolutions of the assignment problem. The algorithm has two phases: a constructive phase and an improvement phase. The constructive phase builds a full schedule by solving successive assignment problems, one for each day in the planning period. The improvement phase uses a couple of procedures that re-solve assignment problems to produce a better schedule. Given the deterministic nature of this algorithm, the same schedule is obtained each time that the algorithm is applied to the same problem instance. The performance of MAPA is benchmarked against published results for almost 250,000 instances from the NSPLib dataset. In most cases, particularly on large instances of the problem, the results produced by MAPA are better when compared to best-known solutions from the literature. The experiments reported here also show that the MAPA algorithm finds more feasible solutions compared with other algorithms in the literature, which suggest that this proposed approach is effective and robust

WebPensa: Uma Ferramenta Para Apoio ao Desenvolvimento do Pensamento Crítico

Este trabalho apresenta um ambiente educacional construído para auxiliar adesenvolver o pensamento crítico, cujo uso estimule alunos e professores ao envolvê-losem uma nova dinâmica na qual a o diálogo, a reflexão e a troca intelectual sedesenvolva como processo de aquisição do conhecimento. O WebPensa é umaferramenta mediadora da Tecnologia Computacional Educativa, e apenas um dosresultados possíveis, baseados em um modelo computacional desenvolvimento einspirado na metodologia de aprendizado definida por Matthew Lipman e nas premissasda Teoria da Atividade

Taquicardia por Reentrada Nodal do Tipo Incomum - Ablaçao por Radiofreqüência

Os autores relatam o caso de uma paciente de 29 anos, com taquicardia supraventricular de QRS estreito e intervalo RP longo refratária ao tratamento clínico, que foi submetida a estudo eletrofisiológico. Os critérios que possibilitaram a definiçao diagnóstica desse tipo de taquicardia foram: a atividade atrial mais precoce registrada no seio coronário proximal, o comportamento dual durante a estimulaçao ventricular e a impossibilidade de antecipar a despolarizaçao atrial por meio da estimulaçao ventricular com o His refratário. Com o diagnóstico eletrofisiológico de taquicardia por reentrada nodal do tipo incomum foi realizada com sucesso a ablaçao da via lenta utilizando energia de radiofreqüência