Publications

O principal objetivo deste artigo é discutir a influência dos meios de comunicação de massa e outros agentes da educação informal sobre as preferências musicais dos estudantes do ensino médio no Brasil. Como dados empíricos, foi realizada uma pesquisa com 940 alunos (mulheres e homens) de Vitória (Espírito Santo-Brasil), que confirmaram os meios de comunicação de massa como os principais agentes determinantes em sua predileção musical, entre os quais a Internet e a Rádio, seguiram pela influência de amigos e televisão. Portanto, é enfatizada a importância de criar políticas públicas que favoreçam o acesso e a disseminação de música através de diferentes meios de comunicação, especialmente enfatizando sua inserção na educação formal e não formal, fato que provavelmente suavizará a potencial soberania dos agentes de mídia.

Esse estudo teve como objetivo implementar um plano de ações para a inclusão da Música no ensino médio em São Luís/MA. Para tanto, buscamos elaborar uma proposta curricular adequada à legislação e aos documentos norteadores da educação, tanto em âmbito nacional como local. Além disso, o trabalho propôs também a elaboração de materiais didáticos para o ensino de Música direcionado ao ensino médio, a partir da consulta a materiais didáticos já existentes e em conformidade com o previsto nas Diretrizes Curriculares da SEDUC-MA. Dessa forma, a pesquisa empregou como método a pesquisa-ação, contando com a participação de 10 escolas públicas, contemplando aproximadamente 1000 alunos. Para coleta de dados, utilizou-se da aplicação de questionários para diagnóstico das turmas e avaliação da proposta desenvolvida, reuniões pedagógicas e relatórios dos professores. Assim, esse trabalho conseguiu obter as seguintes conclusões: 1) a proposta desenvolvida obteve a aprovação dos participantes; 2) os estudantes de ensino médio são favoráveis à inserção da Música enquanto disciplina do currículo escolar; 3) fatores como infraestrutura, água e segurança influem diretamente no desenvolvimento da educação. Dessa forma, espera-se que esse estudo possa contribuir para o surgimento de propostas similares em outras localidades do país.

Despite the advanced stage of diamond thin-film technology, with applications ranging from superconductivity to biosensing, the realization of a stable and atomically thick two-dimensional diamond material, named here as diamondene, is still forthcoming. Adding to the outstanding properties of its bulk and thin-film counterparts, diamondene is predicted to be a ferromagnetic semiconductor with spin polarized bands. Here, we provide spectroscopic evidence for the formation of diamondene by performing Raman spectroscopy of double-layer graphene under high pressure. The results are explained in terms of a breakdown in the Kohn anomaly associated with the finite size of the remaining graphene sites surrounded by the diamondene matrix. Ab initio calculations and molecular dynamics simulations are employed to clarify the mechanism of diamondene formation, which requires two or more layers of graphene subjected to high pressures in the presence of specific chemical groups such as hydroxyl groups or hydrogens.

The electrical transport properties of a four-layered hydrogen-terminated cubic boron nitride sub-nanometer film in contact with gold electrodes are investigated via density functional calculations. The sample exhibits asymmetric metallic surfaces, a fundamental feature that triggers the system to behave like a typical p–n junction diode for voltage bias in the interval −0.2 ≤ V ≤ 0.2, where a rectification ratio up to 62 is verified. Further, in the wider region −0.3 ≤ V ≤ 0.3, negative differential resistance with a peak-to-valley ratio of 10 is observed. The qualitative behavior of the I–V characteristics is described in terms of the hydrogenated cBN film equilibrium electronic structure. Such a film shows metallic surfaces due to surface electronic states at a fraction of eV above and below the Fermi level of the N–H terminated and B–H terminated surfaces, respectively, with a wide bulk-band gap characteristic of BN materials. Such a mechanism is supported by transmission coefficient calculations, with the Landauer–Büttiker formula governing the I–V characteristics.

Fungus-growing ants are a remarkable taxon of New World ants that engage in a mutualistic symbiosis with basidiomycete fungi. Their fungus-gardens are valuable resources and are exploited in countless ways by parasites and other beneficiaries outside of the ant-fungi mutualism. Here, for the first time, we report on the agro-predatory behavior of the ant Megalomyrmex incisus on Mycetophylax conformis and Mycetophylax morschi fungus-growers from sand dunes near Ilhéus, Brazil. Me. incisus workers raided colonies of My. conformis and My. morschi and aggressively antennated, pulled, bit, and stung the fungus-growers, which played dead or retreated on the fungus. Me. incisus quickly usurped the fungus-garden and expelled all Mycetophylax workers. The usurpation closely resembled that described for raids of Me. wettereri on Cyphomyrmex longiscapus, in that the fungus-growers remained passive and avoided confrontation. This passive behavior suggests that Me. incisus uses chemical weapons that facilitate the exploitation of the host colony resources.

Individual acts of cooperation give rise to dynamic social networks. Traditionally, models for cooperation in structured populations are based on a separation of individual strategies and of population structure. Individuals adopt a strategy – typically cooperation or defection, which determines their behaviour toward their neighbours as defined by an interaction network. Here, we report a behavioural experiment that amalgamates strategies and structure to empirically investigate the dynamics of social networks. The action of paying a cost c to provide a benefit b is represented as a directed link point from the donor to the recipient. Participants can add and/or remove links to up to two recipients in each round. First, we show that dense networks emerge, where individuals are characterized by fairness: they receive to the same extent they provide. More specifically, we investigate how participants use information about the generosity and payoff of others to update their links. It turns out that aversion to payoff inequity was the most consistent update rule: adding links to individuals that are worse off and removing links to individuals that are better off. We then investigate the effect of direct reciprocation, showing that the possibility of direct reciprocation does not increase cooperation as compared to the treatment where participants are totally unaware of who is providing benefits to them.

Studies of dynamical stability (chaotic versus regular motion) in galactic dynamics often rely on static analytical models of the total gravitational potential. Potentials based upon self-consistent N-body simulations offer more realistic models, fully incorporating the time-dependent nature of the systems. Here we aim at analysing the fractions of chaotic motion within different morphological components of the galaxy. We wish to investigate how the presence of chaotic orbits evolves with time, and how their spatial distribution is associated with morphological features of the galaxy. We employ a time-dependent analytical potential model that was derived from an N-body simulation of a strongly barred galaxy. With this analytical potential, we may follow the dynamical evolution of ensembles of orbits. Using the Generalized Alignment Index (GALI) chaos detection method, we study the fraction of chaotic orbits, sampling the dynamics of both the stellar disc and of the dark matter halo. Within the stellar disc, the global trend is for chaotic motion to decrease in time, specially in the region of the bar. We scrutinized the different changes of regime during the evolution (orbits that are permanently chaotic, permanently regular, those that begin regular and end chaotic, and those that begin chaotic and end regular), tracing the types of orbits back to their common origins. Within the dark matter halo, chaotic motion also decreases globally in time. The inner halo (r $łt$ 5 kpc) is where most chaotic orbits are found and it is the only region where chaotic orbits outnumber regular orbits, in the early evolution.

Este texto apresenta resultados preliminares de pesquisa que tem sido realizada no âmbito de pós-doutorado, no Centro de Estudos da Metrópole – USP/Cebrap. Busca-se examinar, aqui, as principais tendências de expansão da educação infantil pelos municípios, tendo como referência o novo Plano Nacional de Educação. Inicialmente, faz- se uma breve retrospectiva dos marcos regulatórios da educação infantil. Discute-se, em seguida, o federalismo, a reforma do aparelho do Estado (1995) e sua interface com a educação das crianças pequenas. A instituição do PNE, as metas das capitais brasileiras para a primeira etapa da educação básica e os novos locais de governança são o foco de atenção seguinte do texto. Por fim, conclui-se que a publicação da Lei no 13.019/2014 concorre para reafirmar a tendência de oferta da educação infantil pelo setor público não estatal, tendo em vista as metas do PNE.

In this work hybrids of titanium manopartides and polyaniline are obtained by pulsed electrodeposition at different pH (1.5, 3.9 and 5.9) and characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry, ultraviolet-visible, and Raman spectroscopies. We found that films deposited at pH 5.9 with nanoparticles incorporation are composed of emeraldine meanwhile films without nanoparticles are composed of pernigraniline. As a result, films deposited with nanoparticles incorporation present conductivity 6 times higher than that of films deposited. without nanoparticles. Films deposited at pH 3.9 with or without nanoparticles incorporation are both made of pernigraniline. Even though films with nanoparticles incorporation still present higher conductivity. To explain such a result, we performed first-principles calculations on polyaniline/TiO2 interface. The calculations predict a metallic polyaniline/TiO2 interface in spite of polyaniline and TiO2 being semiconductors. At pH 1.5, the presence of nanoparticles has negligible effect on films characteristics. We believe that at low pH (pH 1.5) H atoms tend to bind TiO2 surface resulting in positively charged nanoparticles, which are further screened by SO4-2 anions. Such a screening layer prevents the physical contact between nanoparticles and polyaniline monomers diminishing the effects of nanopartide presence.

In this work hybrids of titanium manopartides and polyaniline are obtained by pulsed electrodeposition at different pH (1.5, 3.9 and 5.9) and characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry, ultraviolet-visible, and Raman spectroscopies. We found that films deposited at pH 5.9 with nanoparticles incorporation are composed of emeraldine meanwhile films without nanoparticles are composed of pernigraniline. As a result, films deposited with nanoparticles incorporation present conductivity 6 times higher than that of films deposited. without nanoparticles. Films deposited at pH 3.9 with or without nanoparticles incorporation are both made of pernigraniline. Even though films with nanoparticles incorporation still present higher conductivity. To explain such a result, we performed first-principles calculations on polyaniline/TiO2 interface. The calculations predict a metallic polyaniline/TiO2 interface in spite of polyaniline and TiO2 being semiconductors. At pH 1.5, the presence of nanoparticles has negligible effect on films characteristics. We believe that at low pH (pH 1.5) H atoms tend to bind TiO2 surface resulting in positively charged nanoparticles, which are further screened by SO4-2 anions. Such a screening layer prevents the physical contact between nanoparticles and polyaniline monomers diminishing the effects of nanopartide presence.

Evolutionary games on networks traditionally involve the same game at each interaction. Here we depart from this assumption by considering mixed games, where the game played at each interaction is drawn uniformly at random from a set of two different games. While in well-mixed populations the random mixture of the two games is always equivalent to the average single game, in structured populations this is not always the case. We show that the outcome is, in fact, strongly dependent on the distance of separation of the two games in the parameter space. Effectively, this distance introduces payoff heterogeneity, and the average game is returned only if the heterogeneity is small. For higher levels of heterogeneity the distance to the average game grows, which often involves the promotion of cooperation. The presented results support preceding research that highlights the favorable role of heterogeneity regardless of its origin, and they also emphasize the importance of the population structure in amplifying facilitators of cooperation.

This work presents a local search approach to the High School Timetabling Problem. The addressed timetabling model is the one stated in the Third International Timetabling Competition (ITC 2011), which considered many instances from educational institutions around the world and attracted seventeen competitors. Our team, named GOAL (Group of Optimization and Algorithms), developed a solver built upon the Kingston High School Timetabling Engine. Several neighborhood structures were developed and used in a hybrid metaheuristic based on Simulated Annealing and Iterated Local Search. The developed algorithm was the winner of the competition and produced the best known solutions for almost all instances.

The purpose of this paper is to examine the logic of network governance that has been adopted in education policy in Minas Gerais state, Brazil, in the context of basic education, as a result of the increased use of management mechanisms used in state reforms. For this purpose, we take as reference the results of documentary research institution that examined the process of contractual agenda in state education and its deepening as a result of the approach to the “State Network”, covering the period 2003 to 2014. The evidence indicate that the alterations, especially with the insertion of the position of Civil Society Pubic Interest - OSCIPs, have contributed to a change in the form of state action with respect to basic education, reordering its role, which becomes a regulator of the regulation, thus characterizing a “meta-governance”. It concludes highlighting the tensions that the network approach brings to the achievement of public values like equality and citizenship.

The Araçuaí orogen of southeastern Brazil together with the West Congo belt of central West Africa form the Araçuaí–West Congo orogen generated during closure of a terminal segment of the Neoproterozoic Adamastor Ocean. Corresponding to an embayment in the São Francisco–Congo Craton, this portion of the Adamastor was only partially floored by oceanic crust. The convergence of its margins led to the development of the Rio Doce magmatic arc between 630 Ma and 580 Ma. The Rio Doce magmatic arc terminates in the northern portion of the Araçuaí orogen. Granitic plutons exposed in the northern extremity of the arc provide a rare opportunity to study magmatism at arc terminations, and to understand the interplay between calc-alkaline magma production and crustal recycling. The plutons forming the terminus of the arc consist of granodiorites, tonalites and monzogranites similar to a magnesian, slightly peraluminous, calcic- (68%) to calc-alkaline (24%), with minor alkali-calcic (8%) facies, medium- to high-K magmatic series. Although marked by negative Nb–Ta, Sr and Ti anomalies, typically associated with subduction-related magmas, the combined Sr, Nd and Hf isotopic data characterize a crustal signature related to anatexis of metamorphosed igneous and sedimentary rocks, rather than fractional crystallization of mantle-derived magmas. Zircon U–Pb ages characterizes two groups of granitoids. The older group, crystallized between 630 and 590 Ma, experienced a migmatization event at ca. 585 Ma. The younger granitoids, emplaced between 570 and 590 Ma, do not show any evidence for migmatization. Most of the investigated samples show good correlation with the experimental compositional field of amphibolite dehydration-melting, with some samples plotting into the field of greywacke dehydration-melting. The studied rocks are not typical I-type or S-type granites, being particularly similar to transitional I/S-type granitoids described in the Ordovician Famatinian arc (NW Argentina). We suggest a hybrid model involving dehydration-melting of meta-igneous (amphibolites) and metasedimentary (greywackes) rocks for magma production in the northern termination of the Rio Doce arc. The real contribution of each end-member is, however, a challenging work still to be done.

Abstract The High School Timetabling Problem requires the assignment of times and resources to events, while sets of required and desirable constraints must be considered. The most common approach for this problem is to employ metaheuristic methods. This work presents a matheuristic approach that combines a Variable Neighbourhood Search algorithm with mathematical programming-based neighbourhoods for high school timetabling. Computational experiments on well-known benchmark instances demonstrate the success of the proposed hybrid approach, which outperforms the standalone Variable Neighbourhood Search algorithm by far. Additionally, the proposed algorithm was able to improve 15 out of 17 current best known solutions in a very famous benchmark set.

The kinetics of the thermal decomposition of a synthetic ettringite sample was studied between 298 and 820 K in an inert atmosphere for the present work. The ettringite and its thermal decomposition products were characterized using X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. Four endothermic events were observed with thermogravimetry curves, the maxima of which occurred at 366, 397, 537, and 641 K. All events were associated with the loss of water molecules with different degrees of interaction within the ettringite structure. Chemical equations for each decomposition step were proposed based on the percentages of mass loss observed. In addition, for the first time, the activation energies of each ettringite decomposition events were determined by the isoconversional methods of Ozawa–Flynn–Wall, Friedman, and Kissinger–Akahira–Sunose. The modeling revealed that the activation energy varied from ~50 kJ mol−1, characteristic of mass transfer control steps, to ~150 kJ mol−1, which is typical of chemical control, as the temperature increased and the ettringite structure lost water. A total of 32 mol of water was released equivalent to 43.1 % of the initial sample mass.

The application of the Late Acceptance Hill-Climbing (LAHC) to solve the High School Timetabling Problem is the subject of this manuscript. The original algorithm and two variants proposed here are tested jointly with other state-of-art methods to solve the instances proposed in the Third International Timetabling Competition. Following the same rules of the competition, the LAHC-based algorithms noticeably outperformed the winning methods. These results, and reports from the literature, suggest that the LAHC is a reliable method that can compete with the most employed local search algorithms.

{We present a weak-lensing and dynamical study of the complex cluster Abell 1758 (A175

The XHSTT was proposed as a standard format to express a wide range of School Timetabling problems. Although the format is powerful to represent different timetabling features, its application to University Course Timetabling (UCT) problems was not formally studied. The goal of this work is to present encodings from Curriculum-Based Course Timetabling (CB-CTT) and Post-Enrolment Course Timetabling (PE-CTT) to XHSTT and to evaluate how a state-of-art XHSTT solver performs on these problems. Computational experiments performed suggested that this approach is suitable for dealing with UCT: XHSTT solver would be ranked as fourth in CB-CTT track of the Second International Timetabling Competition (ITC2007) and it achieved feasible solutions for most PE-CTT instances within one hour. Although the results do not outperform the best known approaches for these problems, XHSTT solvers were designed to handle a wide range of features and constraints beyond the ones present in these models, making it able to fit the specific requirements of several universities.

Single layer behavior in multilayer epitaxial graphene has been a matter of intense investigation. This is due to the layer decoupling that occurs during growth of graphene on some types of substrates, such as carbon-terminated silicon carbide. We show here that near-edge X-ray absorption spectroscopy can be used to observe the signature of this decoupling. To this end, samples of multilayer graphene from silicon carbide sublimation were grown with different degrees of decoupling. Raman spectroscopy was used to infer the degree of structural decoupling. X-ray grazing-incidence diffraction and scanning tunneling microscopy showed that growth initiates with the presence of bilayer graphene commensurate structures, while layer decoupling is associated to the formation of incommensurate structures observed for longer sublimation time. Near-edge X-ray absorption spectroscopy was used to probe the electronic states above the Fermi energy. Besides the σ* and π* empty states, image potential states are observed and show a clear change of intensity as a function of incident angle. These image potential states evolve from a graphite- to graphene-like behavior as a function of growth time and can be used to infer the degree of structural coupling among layers.

{We present a theoretical study of the vibrational spectrum, in the G band region, of laterally hydrogenated single wall carbon nanotubes through molecular dynamics simulations. We find that bilateral hydrogenation which can be induced by hydrogenation under lateral strain causes permanent oval deformations on the nanotubes and induces the splitting of vibrational states in the G-band region. We propose that such splitting can be used as a Raman fingerprint for detecting nanotubes that have been permanently modified due to bilateral hydrogenation. In particular, our results may help to clarify the recent findings of Araujo and collaborators {[}Nano Lett. 12, 4110 (2012)1 which have found permanent modifications in the Raman G peaks of locally compressed carbon nanotubes. We have also developed an analytical model for the proposed phenomenon that reproduces the splitting observed in the simulations. (C) 2015 Elsevier Ltd. All rights reserved.}

In this work we have used atomically-resolved scanning tunneling microscopy and spectroscopy to study the interplay between the atomic and electronic structure of graphene formed on copper via chemical vapor deposition. Scanning tunneling microscopy directly revealed the epitaxial match between a single layer of graphene and the underlying copper substrate in different crystallographic orientations. Using scanning tunneling spectroscopy we have directly measured the electronic density of states of graphene layers near the Fermi level, observing the appearance of a series of peaks in specific cases. These features were analyzed in terms of substrate-induced perturbations in the structural and electronic properties of graphene by means of atomistic models supported by density functional theory calculations.

We propose an effective model for solute separation from fluids through reverse osmosis based on core-softened potentials. Such potentials have been used to investigate anomalous fluids in several situations under a great variety of approaches. Due to their simplicity, computational simulations become faster and mathematical treatments are possible. Our model aims to mimic water desalination through nano-membranes through reverse osmosis, for which we have found reasonable qualitative results when confronted against all-atoms simulations found in the literature. The purpose of this work is not to replace any fully atomistic simulation at this stage, but instead to pave the first steps towards coarse-grained models for water desalination processes. This may help to approach problems in larger scales, in size and time, and perhaps make analytical theories more viable. (C) 2016 Elsevier B.V. All rights reserved.

We propose an effective model for solute separation from fluids through reverse osmosis based on core-softened potentials. Such potentials have been used to investigate anomalous fluids in several situations under a great variety of approaches. Due to their simplicity, computational simulations become faster and mathematical treatments are possible. Our model aims to mimic water desalination through nano-membranes through reverse osmosis, for which we have found reasonable qualitative results when confronted against all-atoms simulations found in the literature. The purpose of this work is not to replace any fully atomistic simulation at this stage, but instead to pave the first steps towards coarse-grained models for water desalination processes. This may help to approach problems in larger scales, in size and time, and perhaps make analytical theories more viable. (C) 2016 Elsevier B.V. All rights reserved.

Context. The stellar metallicity gradients of disc galaxies provide information on disc assembly, star formation processes, and chemical evolution. They also might store information on dynamical processes that could affect the distribution of chemical elements in the gas phase and the stellar components. Understanding their joint effects within a hierarchical clustering scenario is of paramount importance. Aims: We studied the stellar metallicity gradients of simulated discs in a cosmological simulation. We explored the dependence of the stellar metallicity gradients on stellar age and on the size and mass of the stellar discs. Methods: We used a catalogue of galaxies with disc components selected from a cosmological hydrodynamical simulation performed including a physically motivated supernova feedback and chemical evolution. Disc components were defined based on angular momentum and binding energy criteria. The metallicity profiles were estimated for stars with different ages. We confront our numerical findings with results from the Calar Alto Legacy Integral Field Area (CALIFA) Survey. Results: The simulated stellar discs are found to have metallicity profiles with slopes in global agreement with observations. Low stellar mass galaxies tend to have a larger variety of metallicity slopes. When normalized by the half-mass radius, the stellar metallicity gradients do not show any dependence and the dispersion increases significantly, regardless of the galaxy mass. Galaxies with stellar masses o f around 10$^10$M$_⊙$ show steeper negative metallicity gradients. The stellar metallicity gradients correlate with the half-mass radius. However, the correlation signal is not present when they are normalized by the half-mass radius. Stellar discs with positive age gradients are detected to have negative and positive metallicity gradients, depending on the relative importance of recent star formation activity in the central regions. Conclusions: Our results suggest that inside-out formation is the main process responsible for the metallicity and age profiles. The large dispersions in the metallicity gradients as a function of stellar mass could be ascribed to the effects of dynamical processes such as mergers, interactions and/or migration as well as those regulating the conversion of gas into stars. The fingerprints of the inside-out formation seem better preserved by the stellar metallicity gradients as a function of the half-mass radius.

We present a theoretical study of the vibrational spectrum, in the G band region, of laterally hydrogenated single wall carbon nanotubes through molecular dynamics simulations. We find that bilateral hydrogenation which can be induced by hydrogenation under lateral strain causes permanent oval deformations on the nanotubes and induces the splitting of vibrational states in the G-band region. We propose that such splitting can be used as a Raman fingerprint for detecting nanotubes that have been permanently modified due to bilateral hydrogenation. In particular, our results may help to clarify the recent findings of Araujo and collaborators [Nano Lett. 12, 4110 (2012)1 which have found permanent modifications in the Raman G peaks of locally compressed carbon nanotubes. We have also developed an analytical model for the proposed phenomenon that reproduces the splitting observed in the simulations. (C) 2015 Elsevier Ltd. All rights reserved.

We present a theoretical study of the vibrational spectrum, in the G band region, of laterally hydrogenated single wall carbon nanotubes through molecular dynamics simulations. We find that bilateral hydrogenation which can be induced by hydrogenation under lateral strain causes permanent oval deformations on the nanotubes and induces the splitting of vibrational states in the G-band region. We propose that such splitting can be used as a Raman fingerprint for detecting nanotubes that have been permanently modified due to bilateral hydrogenation. In particular, our results may help to clarify the recent findings of Araujo and collaborators [Nano Lett. 12, 4110 (2012)1 which have found permanent modifications in the Raman G peaks of locally compressed carbon nanotubes. We have also developed an analytical model for the proposed phenomenon that reproduces the splitting observed in the simulations. (C) 2015 Elsevier Ltd. All rights reserved.

A Monte-Carlo-based simulated annealing process combined with ab initio calculations is employed to investigate electronic and structural properties of boron nitride (BN)-doped graphene, in a wide doping range. We find that, for a given BN doping concentration, the doping-induced band gap can vary over an order of magnitude depending on the placement of the B and N atoms. We propose an analytical tight-binding model that reproduces the dependence of the band gap on both the concentration and the morphology obtained in the ab initio calculations and provides an upper bound for the band gap at a given BN concentration. We also predict that the dependence of the band gap with applied tensile stress should be strong, nonmonotonic, and anisotropic, within the range of strain values attainable experimentally.

Evolutionary game theory is a common framework to study the evolution of cooperation, where it is usually assumed that the same game is played in all interactions. Here, we investigate a model where the game that is played by two individuals is uniformly drawn from a sample of two different games. Using the master equation approach we show that the random mixture of two games is equivalent to play the average game when (i) the strategies are statistically independent of the game distribution and (ii) the transition rates are linear functions of the payoffs. We also use Monte-Carlo simulations in a two-dimensional lattice and mean-field techniques to investigate the scenario when the two above conditions do not hold. We find that even outside of such conditions, several quantities characterizing the mixed-games are still the same as the ones obtained in the average game when the two games are not very different.

Understanding layer interplay is the key to utilizing layered heterostructures formed by the stacking of different two-dimensional materials for device applications. Boron nitride has been demonstrated to be an ideal substrate on which to build graphene devices with improved mobilities. Here we present studies on the morphology and optical response of annealed few-layer hexagonal boron nitride flakes deposited on a silicon substrate that reveal the formation of linear wrinkles along well-defined crystallographic directions. The wrinkles formed a network of primarily threefold and occasionally fourfold origami-type junctions throughout the sample, and all threefold junctions and wrinkles formed along the armchair crystallographic direction. Furthermore, molecular dynamics simulations yielded, through spontaneous symmetry breaking, wrinkle junction morphologies that are consistent with both the experimental results and the proposed origami-folding model. Our findings indicate that this morphology may be a general feature of several two-dimensional materials under proper stress-strain conditions, resulting in direct consequences in device strain engineering.

A new experimental procedure was used to analyse the corrosion behaviour of hot-dip Zn coated steel based on the association of the scanning vibrating electrode technique (SVET) and uniaxial tensile strain applied up to 3.1% in 0.01 M NaCl solutions without release of the elastic strain during the test. The nucleation of localized corrosion sites on the coating occurs at very low strain values around the yield point and the maximum current densities increase continuously with the increase of the applied strain. The nucleation of localized corrosion on the Zn surface was favoured by the rupture of the passive film in contact with the solution by the action of slip steps and fine intergranular cracks, rather than by the exposure of the steel substrate. Straining of the Zn coating immersed in the solution was comparatively a much more aggressive condition than straining the sample in air before the corrosion tests. (C) 2015 Elsevier Ltd. All rights reserved.

The current standard cosmological scenario predicts that rich clusters of galaxies are still accreting mass. This dynamical activity is reflected on the intracluster plasma surface brightness, which often shows substructures. A remarkable feature observed in cool-core clusters is the presence of a spiral arm (eg., Laganá et al. 2010). The origin of this arm is probably the sloshing of the cool central gas by the off-axis collision of a passing group or cluster (Ascasibar \amp Markevitch 2006).The rich cluster Abell 2052 was extensively studied in X-ray by Blanton et al. (2011). They show the presence of a spiral structure extending more than 250 kpc, which is comprised of cool gas. Using hydrodynamical N-body simulations of cluster collision, we have recovered the dynamical history of Abell 2052 and reproduced the broad morphology of the spiral feature, as compared with newly computed hardness ratio map and X-ray imaging.We obtain two regimes that reproduce the desired features: (I) a close encounter and a recent event (0.8 Gyr since pericentric passage), and (II) a scenario with a larger impact parameter and older event (almost 2.6 Gyr since pericentric passage). Interestingly, in the second case, we were able to identify an observed optical counterpart - based on the light distribution obtained from the SDSS - at the same redshift of the perturbing galaxy group, with M$_500$ = (1.16\plusmn0.43)x10$^13$ M$_sun$ at about 2 Mpc from the centre of the major cluster.

OBJECTIVE: Considering the growing body of evidence that indicates the contribution of superoxide anions (O2) and other reactive oxygen species (ROS) to the development of hypertension, we assessed whether animal models of hypertension have a benefic effect with tempol, a superoxide dismutase mimetic, to help augment the design of future studies. METHODS: Studies published between July 1998 and December 2012 on blood pressure (BP) in different hypertensive models were obtained after an electronic and manual search of PubMed. In-depth analyses of the methodological quality of the studies and the mean arterial pressure (MAP) changes after treatment with tempol were performed, as well as the subgroup analyses on the route of tempol delivery. RESULTS: Out of the 144 identified studies, 28 were included after screening. The data showed that tempol reduced MAP by computing the standardized mean difference with the value of 4.622 (95% confidence interval 3.24-5.99). The quality of studies included in the meta-analysis was category II; however, omission of details in the trials might have biased the results. There was substantial heterogeneity in the results with an I of 94.45%, which persisted after stratifying for the route of tempol delivery. CONCLUSION: In conclusion, this analysis shows that antioxidant treatment with tempol can reduce BP, suggesting that ROS plays a role in the pathogenesis of increased BP in the hypertension models used in the current research practice.

In this paper we study the distributed optimal control problem for the two-dimensional mathematical model of cancer invasion. Existence of optimal state-control and stability is proved and an optimality system is derived.

We report experimental and theoretical investigations of a new nanomaterial: monolayer and few-layer talc. We show, through atomic force microscopy (AFM) measurements, that natural talc mineral can be mechanically exfoliated down to monolayer flakes. Our AFM-based mechanical characterization also shows that single- and few-layer talc flakes, of several square-microns, present properties similar to those of graphene, BN and MoS 2 , including the existence of folds and the recently reported negative dynamic compressibility. From first principles calculations, we also predict the mechanical properties of monolayer talc. We obtain theoretical values of monolayer talc breaking strength that are near graphene’s record values and its 2D elastic modulus. We also predict that the flexural rigidity of monolayer talc should be more than thirty times larger than that of graphene, but that it could still be bent to very small curvatures without fracturing.

Neste trabalho são estudados modelos matemáticos que descrevem a dinâmica vital e espacial do mosquito Aedes aegypti , principal transmissor da dengue, e sua relação com a população humana. Os modelos analisados têm a dinâmica espacial (difusão e transporte) não-linear, isto é, dependentes da densidade de mosquitos, e a dinâmica vital malthusiana, isto é, sem competição inter-específica. O estudo analítico dos modelos foi feito através da técnica de simetrias de Lie, que permite obter informações sobre o sistema de equações diferenciais em questão, como soluções especiais e trocas de coordenadas que simplifiquem o problema. Esta técnica permitiu encontrar soluções do tipo onda viajante dos modelos estudados, além de soluções adicionais provenientes de simetrias não triviais do modelo.

In this paper, we address the challenge of identifying grain boundaries on the molybdenum disulphide (MoS 2 ) surface at the nanometre scale using a simple self-assembled monolayer (SAM) decoration method. Combined with atomic force microscopy, octadecylphosphonic acid monolayers readily reveal grain boundaries in MoS 2 at ambient conditions, without the need of atomic resolution measurements under vacuum. Additional ab initio calculations allow us to obtain the preferred orientation of the SAM structure relative to the MoS 2 beneath, and therefore, together with the experiments, the MoS 2 crystalline orientations at the grain boundaries. The proposed method enables the visualization of grain boundaries with sub-micrometer resolution for nanodevice investigation and failure analysis.

{Understanding layer interplay is the key to utilizing layered heterostructures formed by the stacking of different two-dimensional materials for device applications. Boron nitride has been demonstrated to be an ideal substrate on which to build graphene devices with improved mobilities. Here we present studies on the morphology and optical response of annealed few-layer hexagonal boron nitride flakes deposited on a silicon substrate that reveal the formation of linear wrinkles along well-defined crystallographic directions. The wrinkles formed a network of primarily threefold and occasionally fourfold origami-type junctions throughout the sample, and all threefold junctions and wrinkles formed along the armchair crystallographic direction. Furthermore, molecular dynamics simulations yielded, through spontaneous symmetry breaking, wrinkle junction morphologies that are consistent with both the experimental results and the proposed origami-folding model. Our findings indicate that this morphology may be a general feature of several two-dimensional materials under proper stress-strain conditions, resulting in direct consequences in device strain engineering.}

In this study, four different adsorbent materials: commercial powdered activated carbon (PAC) from pine tree (PAC-I) and coconut shell (PAC-III) agricultural crop wastes, coal (PAC-II), and carbon nanotubes (CNT) were tested and compared for the removal of sulfamethoxazole (SMX) from spiked aqueous solutions. The kinetic, extrathermodynamic, and thermodynamic parameters for the adsorption of SMX on PACs and CNT were also determined. The results indicate that PAC-I was the best adsorbent for SMX adsorption. SMX adsorption was only favorable with PAC-I and CNT, leading to Gibbs free energies in the range of −39 to −44 kJ mol−1 and showing that the adsorption process was spontaneous in all temperature ranges (15–45 °C) tested. Langmuir model best described SMX adsorption on PAC-I and led to maximum adsorption capacity of ∼131 mg g−1 (at 25 °C), which was ∼4.6 times higher than that observed for CNT. The mechanism of SMX adsorption on PAC-I and CNT was suggested with basis on thermodynamic and extrathermodynamic parameters. The kinetic studies showed the pseudo-second-order model best described SMX adsorption, yielding k2 values of 0.0035 and 0.0016 g mg−1 min−1 for PAC-I and CNT, respectively.

O presente estudo realiza uma análise dos aspectos gerais da responsabilidade civil, a partir da superação da culpa como filtro de aplicação do instituto e a modulação do mesmo pela arquitetura jurídica de proteção do consumidor, vítima de acidentes de consumos decorrentes de defeitos dos produtos. Para tanto, procedeu-se à uma análise da estrutura de proteção estabelecida pelos ordenamentos jurídicos Português e Brasileiro, partindo-se do tratamento constitucional dado ao tema, passando-se pelas normas infra constitucionais que regulam a incidência da responsabilidade objetiva, notadamente no que se refere aos elementos: lesante (fornecedor), lesado (consumidor), dano e indemnização.

A new carboxylate-functionalized sugarcane bagasse (SMA) was prepared via a solvent-free procedure involving esterification of sugarcane bagasse with Meldrum's acid. The optimized conditions provided SMA with a percent weight gain of 86.0% and 4.69 ± 0.20 mmol/g of carboxylic acid groups. SMA was characterized by FTIR, TGA, elemental analysis and SEM. Kinetic experiments showed that the amount of crystal violet adsorbed increased with increasing temperature and equilibrium was reached at 12 h. Adsorption kinetics followed a pseudo-second-order model. The Arrhenius and Eyring models were used to obtain the activation energy and changes in free energy, enthalpy, and entropy of activation for the adsorption process. The calculated activation energy (14.14 kJ/mol) suggested physical adsorption of CV onto SMA. The equilibrium data were well fitted to the Langmuir and Sips isotherms. Maximum adsorption capacity was 692.1 mg/g at 45 °C. Thermodynamic parameters such as changes in free energy, enthalpy and entropy were also determined.

This study described the anaerobic degradation of the azo dye Remazol Golden Yellow RNL (RGY-RNL) using cellulose-immobilized riboflavin (MC 3) as the redox mediator. This new solid support containing immobilized riboflavin was synthesized from succinylated mercerized cellulose, and was characterized by elemental analysis, FTIR, and solid-state 13C NMR. MC 3 was resistant to pH 2–9, and anaerobic degradation of RGY-RNL using MC 3 in the presence of anaerobic sludge yielded a zero order degradation rate constant (k0,obs) equal to 0.189 mg/L h, which was 56% better than experiments carried out without a redox mediator. Color removal efficiency after 48 h of degradation averaged 89.4% in experiments with MC 3 and 72% without the addition of a redox mediator. These results showed that MC 3 can be used to immobilize redox mediators, allowing reduction of wastewater treatment costs.

Research collaboration occurs more frequently today than in the past. As a consequence, cooperation and competition are crucial determinants of academic success. In multiauthored publications, not all authors contribute evenly. Hence, some authors end up with less time or resources to work on parallel projects, decreasing their number of publications. Although detailed information on the contribution of each author in multiauthored publications is generally not available, the order of authors often discloses information on differential contributions. Here we analyze the full data set of Physical Review journals to show that, along with the increasingly number of multiauthored publications, first authors incur costs and last authors are bestowed benefits in terms of number of publications. In other words, authors publishing more often as first authors have fewer publications in the short-term than authors publishing more often as last authors. Using a simplified network representation where direct links represent the costly action of first authors towards last authors, we analyze the evolution of cooperation in multiauthored publications.

During past glacial periods, many species of forest-dwelling animals experienced range contractions. In contrast, species living outside such moist habitats appear to have reacted to Quaternary changes in different ways. The Atlantic Forest represents an excellent opportunity to test phylogeographic hypotheses, because it has a wide range of vegetation types, including unforested habitats covered predominantly by herbaceous and shrubby plants, which are strongly influenced by the harsh environment with strong wind and high insolation. Here, we investigated the distribution of genetic diversity in the endemic sand dune ant Mycetophylax simplex across its known range along the Brazilian coast, with the aim of contributing to the understanding of alternative phylogeographic patterns. We used partial sequences of the mitochondrial gene cytochrome oxidase I and nuclear gene wingless from 108 specimens and 51 specimens, respectively, to assess the phylogeography and demographic history of this species. To achieve this we performed different methods of phylogenetic and standard population genetic analyses. Results The observed genetic diversity distribution and historical demographic profile suggests that the history of M. simplex does not match the scenario suggested for other Atlantic Forest species. Instead, it underwent demographic changes and range expansions during glacial periods. Our results show that M. simplex presents a shallow phylogeographic structure with isolation by distance among the studied populations, living in an almost panmictic population. Our coalescence approach indicates that the species maintained a stable population size until roughly 75,000 years ago, when it underwent a gradual demographic expansion that were coincident with the low sea-level during the Quaternary. Such demographic events were likely triggered by the expansion of the shorelines during the lowering of the sea level. Conclusions Our data suggest that over evolutionary time M. simplex did not undergo dramatic range fragmentation, but rather it likely persisted in largely interconnected populations. Furthermore, we add an important framework about how both glacial and interglacial events could positively affect the distribution and diversification of species. The growing number of contrasting phylogeographic patterns within and among species and regions have shown that Quaternary events influenced the distribution of species in more ways than first supposed.

Este artigo tem como objetivo conhecer a atuação do Pibid nos cursos de licenciatura em música no Brasil com base nos quantitativos de bolsas de iniciação à docência(ID) e subprojetos aprovados, tomando como variáveis de estudo a região, a categoria da IES, a área de conhecimento dos cursos e a formação acadêmica do coordenador de área. Para isso, foram utilizados como fontes de dados o relatório de bolsas referente ao Edital Pibid nº 61/2013, os relatórios de pagamento dos anos2013 a 2015 e os currículos Lattes dos coordenadores presentes em tais relatórios.Os resultados apontaram 1) a predominância de bolsas ID para a região Nordeste e para IES federais; 2) música superou as outras linguagens artísticas e áreas de conhecimento que não estão contempladas como disciplina curricular obrigatória no quantitativo de subprojetos e bolsas ID; 3) a maior parte dos coordenadores dos subprojetos de música não possuem licenciatura na área. São necessários estudos específicos para verificar a influência desses resultados nos trabalhos desenvolvidos em cada realidade.

Cellulose nanocrystals (CNs) were extracted from different sources by acid hydrolysis using H2SO4 and HCl. The thermal decomposition of resulting CNs was studied by thermogravimetric analysis (TGA). The kinetic parameters were determined using the Flynn–Wall–Ozawa (FWO) and Kissinger methods. CNs were also characterized by X-ray diffraction (XRD), Atomic Force Microscopy (AFM), elemental analysis (EA), Zeta Potential (ZP) and degree of polymerization (DP). The results of the XRD analysis showed different profiles, making it possible to differentiate cellulose I from cellulose II. The results obtained by the FWO method showed that cellulose II CNs had an increased activation energy (Ea) with conversion (α), while in CNs of cellulose I the Ea remained constant or decreased slightly. This difference between Ea values for the thermal decomposition of CNs was mainly attributed to different crystalline arrangements of cellulose I and cellulose II, and to the type of acid employed.

A new carboxylated-functionalized sugarcane bagasse (STA) was prepared through the esterification of sugarcane bagasse with trimellitic anhydride. The optimized synthesis conditions yield STA with a percent weight gain of 73.9% and the number of carboxylic acid groups accounted for 3.78 mmol/g. STA was characterized by FTIR, elemental analysis, TGA, PZC, and SEM. Adsorption kinetics followed a pseudo-second-order model. The adsorption rate constant showed the following order: k2,Ni2+ > k2,Cu2+ > k2,Co2+. Four mono- and multi-component isotherm models were used to model the adsorption systems. Monocomponent experimental data were fitted to Langmuir and Sips models; whereas, multicomponent data were fitted to modified extended Langmuir and P-factor models. The maximum adsorption capacities (Qmax,mono) obtained from the Langmuir model were 1.140, 1.197, and 1.563 mmol/g for Co2+, Cu2+, and Ni2+, respectively. The competitive studies demonstrated that the multicomponent adsorption capacity (Qmax,multi) was smaller than Qmax,mono, as a result of the interaction between the metal ions. Desorption studies showed that all metal ions could be fully desorbed from STA.