Publications

Big data patent analysis as an essential tool for the understanding of the technological maturity, competitors, and strategic intelligence for technologies in chemistry.

Mechanical resistant bioactive materials are of high interest for biomedical applications. In this work, we address the improvement in mechanical properties of HA coatings by the addition of a cheap and widely available secondary phase material, the talc from soapstone. The composites hydroxyapatite/talc (HA/talc) were successfully obtained by pulsed electrodeposition and characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Raman spectroscopy, corrosion and wear resistance and biocompatibility tests. We found that the addition of talc greatly improves the mechanical properties of coatings (i. e., wear track and friction coefficient in wear tests were significantly diminished) without diminishing corrosion resistance and biocompatibility. Alamar Blue® tests, alkaline phosphatase activity, and collagen production indicate that the biocomposites are biocompatible and talc itself induce bone maturation.

Difluoroboron β-diketonates complexes are highly luminescent with extensive properties such as their fluorescence both in solution and in solid state and their high molar extinction coefficients. Due to their rich optical properties, these compounds have been studied for their applications in organic electronics such as in self-assembly and applications in biosensors, bio-imaging and optoelectronic devices. The easy and fast synthesis of difluoroboron β-diketonate (BF2dbm) complexes makes their applications even more attractive. Although many different types of difluoroboron β-diketonates complexes have been studied, the cyclic flavanone analogues of these compounds have never been reported in the literature. Therefore, the present work aims to synthesize difluouroboron flavanone β-diketonate complexes, study their photophysical and electrochemical properties and assess their suitability for applications in optoelectronic devices. The synthesis was based on a Baker–Venkataraman reaction which initially provided substituted diketones, which were subsequently reacted with aldehydes to afford the proposed flavanones. The complexation was achieved by reacting flavanones and BF3·Et2O and in total 9 novel compounds were obtained. A representative difluoroboron flavanone complex was subjected to single crystal X-ray diffraction to unequivocally confirm the chemical structure. A stability study indicated only partial degradation of these compounds over a few days in a protic solvent at elevated temperatures. Photophysical studies revealed that the substituent groups and the solvent media significantly influence the electrochemical and photophysical properties of the final compounds, especially the molar absorption coefficient, fluorescence quantum yields, and the band gap. Moreover, the compounds exhibited a single excited-state lifetime in all studied solvents. Computational studies were employed to evaluate ground and excited state properties and carry out DFT and TDDFT level analysis. These studies clarify the role of each state in the experimental absorption spectra as well as the effect of the solvent.

O problema de programação de horários educacionais consiste em alocar recursos e horários a eventos de modo a atender um conjunto de restrições. Esse trabalho aborda o problema de programação de horários do Departamento de Computação e Sistemas da Universidade Federal de Ouro Preto (DECSI/UFOP). Esse problema tem algumas características peculiares que não foram ainda abordadas em conjunto na literatura. Por isso, o presente trabalho tem como principal objetivo propor uma abordagem heurística para o problema. A abordagem se utiliza de um algoritmo construtivo de duas etapas baseado, respectivamente em backtracking e força-bruta e da metaheurística Multi-Start numa estrutura multi-vizinhança para o refinamento das soluções iniciais. Os resultados obtidos foram satisfatórios e o sistema foi adotado pelo departamento para auxiliar na resolução do problema, automatizando por completo o processo de construção dos horários.

This paper describes the preparation and characterization of a versatile Losartan-controlled-release material based on a functionalized cellulosic matrix grafted with the ionic liquid, [(MeO)3Sipmim][Cl]: 1–(trimethoxysilylpropyl)–3–methylimidazolium Chloride. A silanized ionic liquid was used as a solvent and a surface modification agent at the same time, allowing higher anionic drug loading capacity. The anionic Losartan drug release kinetics were evaluated as a model. The Losartan release was made using two distinct media, one at pH 7.4 and the other at 3.0 to simulate blood and stomach pH, respectively. Higher Losartan release-rate 88% at blood pH after 1085 min in comparison with 84% at stomach pH, after 330 min was attained. The higher Losartan release profile in acid pH compared with neutral pH could be associated to the hydrolysis of Si-O bond from the ionic liquid, with the acidic medium acting as a catalyst. This cellulosic matrix modified with ionic liquid showed promising for applications over a wide range of pH-controlled-release systems.

Molecular Dynamics simulations of water confined in carbon nanotubes subjected to external electric fields show that water mobility strongly depends on the confining geometry, the intensity and directionality of the electric field. While fields forming angles of 0° and 45° slow down the water dynamics by increasing organization, perpendicular fields can enhance water diffusion by decreasing hydrogen bond formation. For 1.2 diameter long nanotubes, the parallel field destroys the ice-like water structure increasing mobility. These results indicate that the structure and dynamics of confined water are extremely sensitive to external fields and can be used to facilitate filtration processes.

Molecular Dynamics simulations of water confined in carbon nanotubes subjected to external electric fields show that water mobility strongly depends on the confining geometry, the intensity and directionality of the electric field. While fields forming angles of 0° and 45° slow down the water dynamics by increasing organization, perpendicular fields can enhance water diffusion by decreasing hydrogen bond formation. For 1.2 diameter long nanotubes, the parallel field destroys the ice-like water structure increasing mobility. These results indicate that the structure and dynamics of confined water are extremely sensitive to external fields and can be used to facilitate filtration processes.

We employed PBE and BLYP semi-local functionals and the van der Waals density functional of Dion et al. (2004) (vdW-DF) to investigate structural properties of liquid acetonitrile and methanol. Among those functionals the vdW-DF is the only one that correctly predicts energy minima in inter-molecular interactions between acetonitrile molecules. We found that van der Waals interactions have a negligible effect on H-bonds in methanol chains. However, it significantly increases chain packing resulting in a more dense liquid in comparison to the other two functionals. The overall trend is that the vdW-DF tends to overestimate density and bulk modulus, meanwhile the semi-local functionals tend to underestimate density. Thus, van der Waals interactions play an important role in the properties of liquids in which much stronger dipole-dipole interactions are present.

We employed PBE and BLYP semi-local functionals and the van der Waals density functional of Dion et al. (2004) (vdW-DF) to investigate structural properties of liquid acetonitrile and methanol. Among those functionals the vdW-DF is the only one that correctly predicts energy minima in inter-molecular interactions between acetonitrile molecules. We found that van der Waals interactions have a negligible effect on H-bonds in methanol chains. However, it significantly increases chain packing resulting in a more dense liquid in comparison to the other two functionals. The overall trend is that the vdW-DF tends to overestimate density and bulk modulus, meanwhile the semi-local functionals tend to underestimate density. Thus, van der Waals interactions play an important role in the properties of liquids in which much stronger dipole-dipole interactions are present.

Calcium phosphates are suggested as a CO2 adsorbent via pressure swing adsorption. Amorphous calcium phosphate (ACP) and biphasic calcium phosphate (BCP) (composed of hydroxyapatite and beta-tricalcium phosphate) were investigated for the capture/immobilization of the gas. A fluidized bed was set up to assess the levels of CO2 adsorption by ACP and BCP. A gaseous mixture was synthesized, mimicking the conditions for possible industrial use. The results show a significant reduction in CO2 concentrations. Using DFT calculations, we show that CO2 adsorption increases the stability by reducing the surface energy. The energies involved and preferential adsorption sites were also theoretically predicted.

O presente artigo aborda o problema de cobertura máxima de p-eixos não capacitados com alocação simples (Uncapacitated Single Allocation p-hub Maximal Covering Problem - USApHMCP), que objetiva maximizar a cobertura de um conjunto de nós de uma rede através de p-eixos. Uma heurística baseada na estratégia de busca em descida com vizinhança variável (Variable Neighborhood Descent - VND) foi desenvolvida para o problema. Dois diferentes conjuntos de instâncias, Civil Aeronautics Board (CAB) e Australian Post (AP), são utilizados para avaliar e comparar o desempenho do VND à metaheurística Busca Tabu (Tabu Search - TS) encontrada na literatura. Como resultado, o VND apresentou limites superiores melhores para instâncias de grande porte (AP), bem como um desempenho médio ligeiramente superior em tempo computacional de resolução para as instâncias CAB, de menor porte.

A infraestrutura inadequada e o intenso fluxo de pessoas e veı́culos resultam em problemas associados às vias urbanas no mundo. O Problema de Orientação de Redes Fortemente Conexas (Strong Network Orientation Problem – SNOP) é uma alternativa para amenizar esse cenário na medida em que objetiva minimizar a soma das distâncias percorridas a partir de cada ponto de interseção entre vias, tendo em vista os custos associados à rede urbana. Classificado como NP-Difı́cil, algoritmos heurı́sticos são eficazes para atingir soluções de qualidade, uma vez que obter a melhor solução exige grande esforço computacional. Este artigo apresenta o algoritmo de pesquisa em vizinhança variável General Variable Neighborhood Search (GVNS) para a resolução do SNOP, bem como as estratégias utilizadas. Os resultados obtidos indicam que o GVNS é eficiente em tempo e qualidade de solução quando comparado com outras abordagens aproximadas e exata para o problema.

The reduction by hydrogen and the thermal decomposition of a siliceous nickel laterite ore in the presence of NaCl were studied using thermogravimetric analysis (TGA). Reduction tests on H2 atmosphere in rotary kiln were performed in the presence of NaCl and the product of the reaction was leached in ammoniacal solution. The presence of only 1 pct of NaCl in the furnace increased the nickel extraction values from ≈ 3 to ≈ 90 pct when the experiment was carried out at 850 °C. According to the results of X-ray diffractometry and TGA, the presence of NaCl in the system and the reducing atmosphere of H2 promote the segregation of nickel according to the following steps: (1) Nickel oxide reduction by hydrogen: NiO + H2(g) → Ni + H2O(g). (2) Formation of HCl: Al2SiO5 + 2NaCl + SiO2 + H2O → 2HCl(g) + 2NaAlSiO4. (3) Chlorination of metallic nickel by HCl: Ni + 2HCl(g) → NiCl2 + H2(g). (4) Reduction of nickel chloride by hydrogen: NiCl2 + H2(g) → Ni + 2HCl(g).

A oxidação do concentrado de esfalerita (ZnS) por oxigênio gasoso foi realizada por meio de análise termogravimétrica (TGA). Os produtos de oxidação foram analisados por difratometria de raios X e microscopia eletrônica de varredura (MEV/EDS) e a formação de sulfato de zinco foi detectada durante o processo de oxidação. A pirita presente no concentrado foi aquecida a uma temperatura mais baixa do que a esfalerita e o mecanismo de oxidação estava de acordo com o mecanismo proposto por Dunn J. G. et. al. (1989). A cinética da oxidação da esfalerita foi avaliada por meio do método de isoconversão de Linhas de Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS) e não-linear (MNL) e os resultados sugerem que o processo de oxidação segue um mecanismo complexo. Os valores de energia de ativação encontrados foram superiores a 40kJ/mol na gama completa de conversão sugerindo que a etapa de controle ocorre por meio de reação química.

We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes with different degrees of eccentricity at 300 K. We found a water structural transition between tubular-like to single-file for (7,7) nanotubes associated with change from a high to low mobility regimes. Water is frozen when confined in a perfect (9,9) nanotube and it becomes liquid if such a nanotube is deformed above a certain threshold. Water diffusion enhancement (suppression) is related to a reduction (increase) in the number of hydrogen bonds. This suggests that the shape of the nanotube is an important ingredient when considering the dynamical and structural properties of confined water.

Phenazine derivative molecules were studied using steady state and time resolved fluorescence techniques and demonstrated to lead to strong formation of aggregated species, identified as dimers by time dependent density functional theory calculations. Blended films in a matrix of Zeonex®, produced at different concentrations, showed different contributions of dimer and monomer emissions in a prompt time frame, e.g. less than 50 ns. In contrast, the phosphorescence (e.g. emission from the triplet state) shows no significant effect on dimer formation, although strong dependence of the phosphorescence intensity on concentration is observed, leading to phosphorescence being quenched at higher concentration.

Tin telluride (SnTe) ultrathin films were deposited electrochemically on polycrystalline and monocrystalline gold substrates using the electrochemical atomic layer epitaxy (ECALE) method. The electrochemical behaviors of Sn and Te were studied systematically by means of cyclic voltammetry. Cyclic voltammetry curves for Sn displayed a broad peak in the region between -0.15 V and -0.35 V, which was related to the under-potential deposition (UPD), while the curves for Te displayed a peak at 0.3 V for Te UPD. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM) were employed for the characterization of the ultrathin SnTe films. XRD and Raman spectroscopy confirmed the deposition of a single SnTe phase, while SEM revealed that the deposits were composed of nanocrystallites.

We report on an experimental investigation of serpentine, an abundant phyllosilicate, as an alternative source of two-dimensional (2D) nanomaterials. We show, through scanning probe microscopy (SPM) measurements, that natural serpentine mineral can be mechanically exfoliated down to few-layer flakes, where monolayers can be easily resolved. The parent serpentine bulk material was initially characterized via conventional techniques like XRD, XPS, FTIR and Raman spectroscopies and the results show that it is predominantly constituted by the antigorite mineral. From ab initio calculations using DFT, we also determine the geometry and electronic structure of antigorite, the observed structural form of serpentine. Additionally, we further characterized electrical and mechanical properties of the obtained 2D material flakes using SPM and broadband synchrotron infrared nanospectroscopy. Wavelength tuning of the serpentine vibrational resonances, assigned to in- and out-of-plane molecular vibrations, are observed and compared with the FTIR characterization of the parent bulk material. They show that there is no degradation of serpentine`s structural properties during its mechanical exfoliation down to nanometer-thin sheets. Therefore, our results introduce the serpentine mineral as an attractive low-cost candidate in 2D materials applications.

We report on an experimental investigation of serpentine, an abundant phyllosilicate, as an alternative source of two-dimensional (2D) nanomaterials. We show, through scanning probe microscopy (SPM) measurements, that natural serpentine mineral can be mechanically exfoliated down to few-layer flakes, where monolayers can be easily resolved. The parent serpentine bulk material was initially characterized via conventional techniques like XRD, XPS, FTIR and Raman spectroscopies and the results show that it is predominantly constituted by the antigorite mineral. From ab initio calculations using density functional theory, we also determine the geometry and electronic structure of antigorite, the observed structural form of serpentine. Additionally, we further characterized electrical and mechanical properties of the obtained 2D material flakes using SPM and broadband synchrotron infrared nanospectroscopy. Wavelength tuning of the serpentine vibrational resonances, assigned to in- and out-of-plane molecular vibrations, are observed and compared with the FTIR characterization of the parent bulk material. They show that there is no degradation of serpentine’s structural properties during its mechanical exfoliation down to nanometer-thin sheets. Therefore, our results introduce the serpentine mineral as an attractive low-cost candidate in 2D materials applications.

Discute-se, no presente trabalho, a reconstrução da identidade, por meio de processos desencadeados pela memória do vivido, mas, tendo como elemento central de análise, a produção do discurso formulado de um lugar discursivo que é do “Outro”, do colonizador. A análise da tensão de re-estruturação do “Eu”, a partir da língua desse Outro, é desenvolvida na perspectiva comparada de dois romances: “O outro pé da sereia”, de Mia Couto, e “Bom dia Camaradas”, de Ondjaki, considerando, em ambos, o processo de construção da identidade do narrador. Para tanto, utiliza-se como categoria teórica privilegiada os trabalhos localizados na interface da teoria da literatura, que trabalham com a temática do tempo e os estudos culturais.

The goal of this article is to analyse the musical preferences of Brazilian students by considering the variables of gender and religion. Using random sampling, a class was selected from each high school year group of 10 public schools in the city of São Luís (Brazil).The total study sample consisted of 658 students: 358 females (54.4%) and 300 males (45.6%). Of these, 343 (52.1%) were Protestants and 315 (47.9%) were Catholics, and their ages ranged from 14 to 19 years (M = 16.24 years old, SD = 1.14). For the data collection, a version of the Questionnaire on Musical Style Preferences by Lorenzo, Herrera, and Cremades (2008) was used; however, it was shortened and culturally adapted to the Brazilian context. The participants were asked to evaluate how often they listened to 19 different styles of music. The overall results indicated that the participants’ musical preferences were heavily influenced by mass media. However, ANOVA results indicated significant differences and a variety of size effects in the frequency of musical listening based on gender and religion. Females had a greater preference for styles with emotional content, dance music and music with a strong connection to mass culture, while males preferred more vigorous styles. Regarding religion, Protestants had a stronger preference for gospel music, while Catholic preferences were more diverse.

Scanning probe microscopy and ab initio calculations reveal modifications on the electronic and structural properties of graphene/h-BN heterostructures induced by compression. Using AFM and EFM techniques, with charge injection being made in the heterostructures at different pressures, the charge injection efficiency monotonically decreases with increasing pressure for monolayer-graphene (MLG)+BN heterostructures, indicative of a conductor-insulator electronic transition. Bilayer-graphene (BLG)+BN and trilayer-graphene (TLG)+BN heterostructures show a non-monotonic behavior of charge injection versus pressure, indicative of competing electronic structure modifications. First-principle calculations of these systems indicate a pressure-induced van der Waals-to-covalent interlayer transition, where such interlayer covalent binding, in the presence of water molecules, results in a disordered insulating structure for the MLG + BN case, while it leads to an ordered conducting structure for both BLG + BN and TLG + BN heterostructures. These opposing effects may have a strong influence on graphene/h-BN-based electronic devices and their physics under pressurized environments.

The cementation of copper and cadmium by zinc powder was investigated in order to assess the influence of different parameters in the process. The results showed that the process follows a first order reaction with two stages in both systems. In the system Cu/Zn, the second stage is faster than the first while in the system Cd/Zn the second stage is slower than the first. In the system Cu/Zn, the variation on the surface area of copper cement followed a power law and a straight line was obtained by plotting –ln([Cu2+]/[Cu2+] 0 ) against t3/2, the activation energy was calculated as 16.3kJ. In the system Zn/Cd the surface area available for reaction decreased as a result of the cement agglomeration. On the experiments carried out with ions Cu2+ and Cd2+ in solution, purer copper cement was obtained when the experiments were carried out in the presence of less than stoichiometric amount of zinc powder and longer reaction times.

Os consumidores de bens e serviços de um determinado mercado são atraídos por um conjunto de atributos de valor que direta ou indiretamente os qualificam em relação aos seus concorrentes. Por outro lado, embora o “preço” seja apenas um dentre os vários atributos, ele muitas vezes é interpretado como uma variável resposta que reúne os demais, justamente pelo seu grau de relevância quanto à restrição orçamentária dos consumidores. Esse artigo objetiva entender o grau de influência e correlação de um conjunto de variáveis explicativas nos preços de imóveis residenciais ofertados para locação e venda na cidade de João Monlevade-MG, via modelos de regressão linear multivariada. A metodologia proposta se baseia em informações reais referentes aos preços ofertados na cidade e suas características estruturais e locacionais, a citar: quantidade de quartos e vagas na garagem; quantitativo de ocorrências policiais; proximidade com o centro comercial, postos de saúde e escolas estaduais mais próximas. Como resultado, foi possível obter um conjunto de equações matemática capazes de explicar o preço em função das variáveis preditoras, bem como entender a relação entre estas variáveis.

Energetics and electronic properties of three-layered hBN nanoribbons, with reconstructed edges, were investigated, using density functional theory. Such edges present lines of pentagonal and heptagonal rings, where homopolar B-B and N-N bonds exist. The homopolar bonds and their distribution, determine the energetic stability of hBN nanoribbons. The structures with the lowest amount of homopolar bonds presents a value of formation energy smaller than the single hBN layer, which suggests that such kind of reconstruction may indeed occur in real three-layered hBN systems. In addition, our results suggest that reconstructed edges on hBN nanoribbons are more stable than their carbon counterparts.

Esse trabalho visa investigar e compreender a similaridade entre os diferentes bairros que possuem imóveis anunciados para venda e aluguel da cidade de João Monlevade, Minas Gerais, por meio de análises de clusters. Trata-se de uma técnica de análise multivariada que compõem a Engenharia da Qualidade, que é uma das grandes áreas de atuação da Engenharia de Produção. As características dos imóveis estudados são: preço; quantidade de quartos, vagas na garagem e ocorrências criminais; e as distâncias em relação ao centro comercial, postos de saúde e escolas estaduais mais próximas. Através de uma análise de sensibilidade utilizando-se de três diferentes graus de similaridade, esse artigo identificou e comparou a formação de clusters entre que os bairros com imóveis para venda e locação. Foi possível perceber que existe uma maior similaridade entre os bairros com anúncios de vendas de imóveis, quando comparados aos bairros com imóveis para locação, uma vez que menos clusters foram formados.

Abstract The use of chitosan functionalized silica for benznidazole delivery in the treatment of neglected disease such as Chagas disease is one of the forms not yet explored, but with great potential for this therapy, as little is known about nanoformulations for the treatment of Chagas disease. In this work, we used chitosan-succinate covalently attached to the surface pore of \MSNs\ to act as anchor for benznidazole as a delivery system. The samples were characterized structurally and chemically with multiple techniques. The applicability of functionalized \MSNs\ as platforms for benznidazole delivery into T. cruzi parasites was assessed. The results demonstrate that the proposed system is a potential promising nanoplatform for drug and gene delivery targeting neglected diseases such as Chagas disease.

Apresenta-se a noção de permeabilidade como categoria analítica que auxilia o exame de dinâmicas de privatização presentes em iniciativas atuais na educação básica. O conceito de permeabilidade refere-se aqui à natureza de padrões relacionais forjados na implementação de políticas educacionais. Assim, examinam-se dois movimentos que se realizam concomitantemente: de um lado, iniciativas do poder público de assimilar e adaptar conhecimentos desenvolvidos no setor privado; de outro, a transferência de prestação de serviços públicos para instituições privadas. Sistematizam-se aportes da literatura que contribuem para a compreensão da ampla gama de regimes de regulação. À luz desses subsídios, são mencionadas iniciativas que ilustram alterações nos modos de gerenciar e prover a educação básica.

Este estudio analiza diferentes métodos de enseñanza-aprendizaje de violoncello en conservatorios de música de Andalucía (España) y las implicaciones educativas que estos puedan tener en el proceso de enseñanza-aprendizaje de este instrumento, especialmente para el profesorado. Se ha utilizado una metodología de tipo descriptivo, mediante análisis de contenido. Como instrumento de recogida de datos se ha usado una ficha adaptada de Garde, Gustems y Calderón (2015), compuesta por 41 item. Se llevó a cabo una comparación de los diferentes métodos de iniciación al violonchelo empleados en los conservatorios participantes, en función de cuatros dimensiones de análisis: aspectos didáctico-metodológicos, parámetros físicos, aspectos psicológicos y sensibilización musical. Sobre la primera dimensión, los resultados muestran una divergencia entre los textos analizados respecto al rol del profesor en el proceso didáctico. Con relación a los parámetros físicos, se observa una escasez de contenidos en los diferentes métodos que no ayuda a prevenir posibles problemas de salud y de interpretación en el alumnado novel. Aparece también poca atención respecto al desarrollo de aspectos psicológicos (concentración y memoria). Por último, los manuales analizados muestran especial atención hacia los aspectos vinculados a la dimensión sensibilización musical (afinación, sentido rítmico y hábitos de estudio). Los resultados de este estudio ponen de relieve la importancia de la formación del profesorado en metodologías de enseñanza activas, creativas y contemporáneas, ya que la mayoría de los métodos analizados deja en manos de los docentes aspectos de alta relevancia en el desarrollo musical del alumnado.

O presente trabalho tem como objetivo examinar aspectos atuais referentes à educação superior, tais como qualidade, e por extensão, satisfação dos estudantes. Para tanto, foi realizada uma ampla e rigorosa revisão de literatura com o intuito de situar as discussões correntes sobre a influência da qualidade em um mercado dinâmico e competitivo da educação terciária, e, principalmente, a importância da satisfação dos alunos com a educação recebida, que possibilita dentre outras vantagens: motivação, retenção, recrutamento, captação de recursos e lealdade. Destaca-se a importância da satisfação frente à infraestrutura, pois a qualidade da mesma influi na satisfação do estudante com o serviço educacional prestado e, consequentemente, repercute em seu rendimento acadêmico. Ademais, tratou-se sobre a satisfação com relação ao ensino, no qual o aluno, por meio de uma avaliação do trabalho docente, indica possibilidades de melhorias no processo ensino-aprendizagem.

The aim of this paper is to investigate the existence of optimal controls for systems described by stochasticpartial differential equations (SPDEs) with locally monotone coefficients controlled by external forces whichare feedback controls. To attain our objective we adapt the argument of Lisei (2002) where the existence ofoptimal controls to the stochastic Navier–Stokes equation was studied. The results obtained in the presentpaper may be applied to demonstrate the existence of optimal controls to various types of controlledSPDEs such as: a stochastic nonlocal equation and stochastic semilinear equations which are locally monotone equations; we also apply the result to a monotone equation such as the stochastic reaction–diffusionequation and to a stochastic linear equation.

In this paper we study the distributed problem for the two-dimensional mathematical model of the invasion of a healthy tissue by a generic solid tumor that has been vascularized, due to coupled parabolic systems. We prove the existence, uniqueness, and local null controllabilty.

O presente artigo é uma versão condensada de monografia apresentada em 2011 na Universidade Federal do Maranhão, no curso de Educação Artística, com foco na atuação do fotógrafo Márcio Vasconcelos que tem um olhar para a temática social, cultura popular, religião afro-maranhense. Márcio Vasconcelos se intitula “autodidata e independente”, pois não está a serviço de outrem, portanto, voltado para produção independente, “autoral”, onde elabora e executa seus projetos, submetendo-os aos editais da cultura, dentre os quais, Petrobrás Cultural e Minc. Recebeu diversos prêmios nacionais e internacionais, como o 1º Prêmio Nacional de Expressões Culturais Afro-Brasileiras/2010 da Fundação Cultural Palmares/Petrobrás com o projeto “Zeladores de Voduns do Benin ao Maranhão”; “Nagon Abioton – Um Estudo Fotográfico e Histórico sobre a Casa de Nagô”, Lei Rouanet e no Programa Petrobrás Cultural/2009, editado em livro sobre um dos terreiros mais antigos do Tambor de Mina no Maranhão; Ensaio fotográfico “Na trilha do Cangaço – um ensaio pelo sertão que Lampião pisou”, projeto contemplado em 2010 com o XI Prêmio Funarte Marc Ferrez de Fotografia, disponível em http://www.natrilhadocangaco.com.br/ensaio.php, (atualmente, se encontra editado em livro). A pesquisa pretende contribuir para a produção científica no espaço acadêmico da fotografia no Maranhão, sem pretensão de esgotar o tema, mas fomentar e instigar novas pesquisas, tendo em vista a abordagem escolhida. É sustentada teoricamente por: Freund (1995), Kubrusly (2006) e outros. Apresentar-se-á as ideias gerais do escopo geral da monografia como o surgimento da fotografia e o curto tempo em que esta chegou ao Maranhão. Invenção anunciada publicamente pela Academia de Ciências de Paris em 1839, a fotografia chegara ao Maranhão em 1846, segundo o Album do Maranhão em 1908, Gaudêncio Cunha (1987). A arte maranhense é rica em diversidade, está intrinsecamente ligada à cultura popular – o branco, o negro, o índio, todos estão presentes na arte produzida no Maranhão, seja nas artes visuais, teatro, música, dança; nas manifestações culturais: Bumba-meu-boi, ritos, mitos, reggae, Terecô, Divino Espírito Santo.

This article presents the notion of permeability as an analytical category for examining the privatization dynamics in current initiatives in early childhood, primary and secondary education. The concept of permeability refers here to the nature of relational patterns shaped in the implementation of educational policies. Therefore, the article examines two concomitant movements: on the one hand, public authorities’ initiatives to assimilate and adapt knowledge developed in the private sector; on the other hand, the transfer of public services to private institutions. It also systematizes literature inputs which contribute to the understanding of the wide range of regulatory regimes. Initiatives that illustrate changes in the forms of management and provision of early childhood, primary and secondary education are discussed in light of these contributions.

The Araçuaí-West Congo orogen (AWCO) is one of the various components of the Brasiliano/Pan-African orogenic network generated during the amalgamation of West Gondwana. In the reconstructions of Gondwana, the AWCO, encompassing the Araçuaí orogen of South America and the West Congo belt of Southwestern Africa, appears as a tongue-shaped orogenic zone embraced by the São Francisco-Congo craton. Differing from the vast majority of the known orogens owing to its singular confined setting, the AWCO contains a large amount of orogenic igneous rocks emplaced in all stages of its tectonic evolution. We present new and revised information about the oldest Ediacaran granitic assemblage, the G1 Supersuite, which together with the Rio Doce Group defines the Rio Doce magmatic arc, and then we propose a new tectonic setting for the arc. Field relationships and mineralogical compositions of the G1 Supersuite allow us to characterize three lithofacies associations, Opx-bearing rocks, enclave-rich Tonalite–Granodiorite and enclave-poor Granite–Tonalite, suggesting different crustal levels are exposed in the central part of the Araçuaí orogen. The region is interpreted to represent a tilted crustal section, with deep arc roots now exposed along its western border. Chemically, these plutonic associations consist mostly of magnesian, metaluminous to slightly peraluminous, calc-alkaline to alkali-calcic and medium- to high-K acidic rocks. The dacitic and rhyolitic rocks of the Rio Doce Group are mainly magnesian, peraluminous, calcic to calc-alkaline, and medium- to high-K acidic rocks. Zircon U–Pb data constrain the crystallization of the granitoids between ca. 625 and 574 Ma, while the age of the metamorphosed volcanic rocks is around ca. 585 Ma. Thus, within errors, these rock associations likely belong to the same magmatic event and might represent the subduction-related, pre-collisional, evolution of the Araçuaí orogen. In addition, whole-rock Sm–Nd isotopic compositions show variable negative εNd(t) values between −6.7 and −13.8, and TDM model ages varying from 1.39 to 2.26 Ga, while εHf(t) vary between −5.2 and −11.7, with TDM ages from 1.5 to 2.0 Ga. Thus, predominantly constructed upon Paleoproterozoic (Rhyacian) basement, the Rio Doce arc shows crustal sources largely prevailing over mantle sources, providing a well-studied example to be compared with similar orogenic settings around the world.

Buscamos, a partir da percepção de gestores, conhecer as lógicas de gestão escolar em municípios mineiros, por meio da sua interface com iniciativas de medida e avaliação federais. No total, participaram cinco escolas públicas de quatro municípios do estado de Minas Gerais. Realizamos entrevistas semiestruturadas individualmente com cinco gestoras.  Utilizamos uma abordagem qualitativa, sendo as entrevistas analisadas por meio de análise de conteúdo. Nesse sentido, empregamos as seguintes categorias analíticas: a) modificação da gestão escolar; b) Ideb e qualidade em educação; c) modificação do trabalho pedagógico do professor. Em síntese, nossos resultados apontam para um forte efeito de indução que as avaliações externas e o Ideb têm produzido nas escolas e nos profissionais da educação, o que envolve questões como o estabelecimento de metas, monitoramento intenso das escolas e replanejamento institucional. Portanto, identificamos diversos usos e implicações do Ideb e avaliações externas. Tomados em conjunto, nossos resultados corroboram a literatura educacional. 

In this paper we propose some mathematical models for the transmission of dengue using a system of reaction–diffusion equations. The mosquitoes are divided into infected, uninfected and aquatic subpopulations, while the humans, which are divided into susceptible, infected and recovered, are considered homogeneously distributed in space with a constant total population. We find Lie point symmetries of the models and we study theirs temporal dynamics, which provides us the regions of stability and instability, depending on the values of the basic offspring and the basic reproduction numbers. Also, we calculate the possible values of the wave speed for the mosquitoes invasion and dengue spread and compare them with those found in the literature.

A fim de identificar o que é mais relevante para o consumidor na escolha de um imóvel e entender as características que impactam no preço final, este artigo visa entender a correlação entre as variáveis estudadas e aplicar modelos de regressão múltipla para analisar os preços ofertados de imóveis residenciais para locação e venda na cidade de João Monlevade-Minas Gerais. Esse método utiliza informações referentes aos preços ofertados dos imóveis, juntamente com as suas características estruturais e locacionais, sendo elas: quantidade de quartos e vagas na garagem, quantitativo de ocorrências policiais, proximidade com o centro comercial, postos de saúde e escolas estaduais mais próximas. Como resultado, foi possível obter uma relação matemática capaz de explicar o preço em função das variáveis preditoras, bem como a relação entres estas variáveis.

This article analyzes the relationship between musical preference and type of personality in a large group of Brazilian young and adult participants (N = 1050). The study included 25 of 27 states of Brazil and individuals aged between 16 and 71 years (M = 30.87; SD = 10.50). Of these, 500 were male (47.6%) and 550 were female (52.4%). A correlational study was carried out applying two online questionnaires with quality parameters (content-construct validity and reliability), one on musical preference and the other on personality. The results indicate four main findings: (1) the musical listening of the participants is limited to a reduced number of styles, mainly Pop music and others, typical of Brazilian culture; (2) the Brazilian context supposes a determining aspect in the low preference of non-Brazilian music; (3) there is a positive correlation between most personality types analyzed and the Latin, Brazilian, Classical and Ethnic musical styles. A negative correlation between these types of personality and the consumption of Rock music was also observed; (4) musical preferences are driven not only by personality but in some cases they are also driven by socio-demographic variables (i.e., age and gender). Likewise, this work shows how participants make use of music in personality aspects that may be of interest for the analysis of socio-affective behavior (personality) as well as according to different socio-demographic variables (e.g., age and gender). More cross-cultural research on musical preference and personality would need to be carried out from a global perspective, framed in the context of social psychology and studies of mass communication.

We propose, based on results of first-principles calculations, that nanoporous graphene and h-BN might be efficiently produced from B–C–N layers as precursors. In our calculations, we find that the removal of the h-BN islands that naturally occur in BN-doped graphene, forming nanoporous graphene, requires less energy than if pristine graphene is used as a precursor. The same reduction ΔEf in pore formation energy is found for nanoporous h-BN obtained from graphene-doped BN as a precursor. ΔEf is found to increase linearly as a function of the number of B–C and N–C bonds at the island boundary, with the slope being nearly the same for either porous graphene or porous h-BN. This is explained by an analytical bond-energy model. In the case of porous graphene, we find that the pore formation energy would be further reduced by passivation by pyridinic and quaternary remnant nitrogen atoms at the pore edges, a mechanism that is found to be more effective than the passivation by hydrogen atoms. Both mechanisms for pore formation energy reduction should lead to a possibly efficient method for nanoporous graphene production.

Tendo, portanto, como referência, as propostas de reforma explicita- das pelos Programas de Governo de Aécio Neves (2003-2006); (2007-2010) e de Antônio Anastasia (2011-2014), examina-se neste arti- go a dimensão normativo-legal que as viabilizou, sublinhando a prefe- rência do Executivo pela utilização de leis delegadas e que culmina com a renúncia do Legislativo em legislar sobre a reforma estatal, de modo geral, e sobre a educacional, de maneira específica.

Abstract Isoxazoles have well established biological activities but, have been underexplored as synthetic intermediates for applications in materials science. The aims of this work are to synthesis a novel isoxazole and analyze its structural and photophysical properties for application in electronic organic materials. The novel bis (phenylisoxazolyl) benzene compound was synthesized in four steps and characterized by NMR, high resolution mass spectrometry, differential thermal analysis, infrared spectroscopy, cyclic voltammetry, ultraviolet–visible spectroscopy, fluorescence spectroscopy, \DFT\ and \TDDFT\ calculations. The molecule presented optical absorption in the ultraviolet region (from 290 nm to 330 nm), with maximum absorption length centered at 306 nm. The molar extinction coefficients (ε), fluorescence emission spectra and quantum efficiencies in chloroform and dimethylformamide solution were determined. Cyclic voltammetry analysis was carried out for estimating the \HOMO\ energy level and these properties make it desirable material for photovoltaic device applications. Finally, the excited-state properties of present compound were calculated by time-dependent density functional theory (TDDFT).

O presente artigo busca analisar o percurso histórico da Rádio UFOP Educativa 106.3 FM, explorando os principais pontos que marcaram a trajetória dessa emissora pública que transmite desde 1998. No primeiro momento é discutido o segmento de rádio público e educativo no país para, a partir disso, apresentar a história da Rádio UFOP Educativa 106.3 FM. A metodologia adotada foi a revisão de literatura. A entrevista semiestruturada foi utilizada para coletar relatos sobre parte da sua memória, a fim de compreender as transformações que o veículo passou ao longo da sua existência.

In the present work, we use atomic force microscopy nanomanipulation of 2D-material standing folds to investigate their mechanical deformation. Using graphene, h-BN and talc nanoscale wrinkles as testbeds, universal force–strain pathways are clearly uncovered and well-accounted for by an analytical model. Such universality further enables the investigation of each fold bending stiffness κas a function of its characteristic height h 0. We observe a more than tenfold increase of κ as h 0increases in the 10–100 nm range, with power-law behaviors of κ versus h 0 with exponents larger than unity for the three materials. This implies anomalous scaling of the mechanical responses of nano-objects made from these materials.

 

We report a first-principles study of edge-reconstructed, few-layered graphene nanoribbons. We find that the nanoribbon stability increases linearly with increasing width and decreases linearly with increasing number of layers (from three to six layers). Specifically, we find that a three-layer 1.3 nm wide ribbon is energetically more stable than the C60 fullerene, and that a 1.8 nm wide ribbon is more stable than a (10,0) carbon nanotube. The morphologies of the reconstructed edges are characterized by the presence of five-, six-, and sevenfold rings, with sp3 and sp2 bonds at the reconstructed edges. The electronic structure of the few-layered nanoribbons with reconstructed edges can be metallic or semiconducting, with band gaps oscillating between 0 and 0.28 eV as a function of ribbon width.

In this paper, we prove that if the initial data is small enough, we obtain an explicit L∞(QT)‐estimate for a two‐dimensional mathematical model of cancer invasion, proving an explicit bound with respect to time T for the estimate of solutions.

Resumo Este trabalho objetiva descrever e apresentar algumas das variáveis determinantes para a formação dos preços praticados no mercado imobiliário de compra, venda e aluguéis residenciais da cidade de João Monlevade-MG. Trata-se de uma pesquisa baseada em dados reais do ano de 2016 obtidos por meio de pesquisas em websites e visitas de campo em locais públicos e privados. Os dados da oferta e da demanda foram coletados e organizados em planilhas eletrônicas, a partir de critérios: (i) estruturais, por tipo de imóvel (apartamento ou casa) e quantidade de cômodos; (ii) geográficos, através da divisão por bairros e suas vias de acesso; e (iii) geradores de informação, pelas diferentes fontes de coleta; resultando em uma análise estatística descritiva do mercado. Para justificar os resultados obtidos na análise estatística foram levantados dados referentes à infraestrutura de saneamento básico e ao acesso a serviços de utilidade pública (saúde, educação, transporte, comércio e segurança), que poderiam influenciar na decisão de escolha dos consumidores. Fatores como a violência e a localização dos bairros em relação ao centro comercial foram elementos de maior impacto na formação dos preços.

The aim of this paper is to investigate the existence of optimal controls for systems described by stochastic partial differential equations (SPDEs) with locally monotone coefficients controlled by different external forces which are feedback controls. We apply our result to various types of SPDEs such as the stochastic 2-D Navier-Stokes equation, the stochastic nonlocal equation, stochastic linear equations and stochastic semilinear equations.

 

Educational timetabling problems require the assignment of times and resources to events, while sets of required and desirable constraints must be considered. The XHSTT format was adopted in this work because it models the main features of educational timetabling and it is the most used format in recent studies in the field. This work presents new cuts and reformulations for the existing integer programming model for XHSTT. The proposed cuts improved hugely the linear relaxation of the formulation, leading to an average gap reduction of 32%. Applied to XHSTT-2014 instance set, the alternative formulation provided four new best known lower bounds and, used in a matheuristic framework, improved eleven best known solutions. The computational experiments also show that the resulting integer programming models from the proposed formulation are more effectively solved for most of the instances.