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Opinion dynamics systems on barabási-albert networks : biswas-chatterjee-sen model.
No full textA discrete version of opinion dynamics systems, based on the Biswas–Chatterjee–Sen
(BChS) model, has been studied on Barabási–Albert networks (BANs). In this model, depending
on a pre-defined noise parameter, the mutual affinities can assign either positive or negative values.
By employing extensive computer simulations with Monte Carlo algorithms, allied with finite-size
scaling hypothesis, second-order phase transitions have been observed. The corresponding critical
noise and the usual ratios of the critical exponents have been computed, in the thermodynamic limit,
as a function of the average connectivity. The effective dimension of the system, defined through a
hyper-scaling relation, is close to one, and it turns out to be connectivity-independent. The results
also indicate that the discrete BChS model has a similar behavior on directed Barabási–Albert networks
(DBANs), as well as on Erdös–Rènyi random graphs (ERRGs) and directed ERRGs random graphs
(DERRGs). However, unlike the model on ERRGs and DERRGs, which has the same critical behavior
for the average connectivity going to infinity, the model on BANs is in a different universality class to
its DBANs counterpart in the whole range of the studied connectivities
The orphan G protein-coupled receptor, GPR139, is expressed in the hypothalamus and is involved in the regulation of body mass, blood glucose, and insulin.
No full textGPR139 is an orphan G-protein-coupled receptor that is expressed in restricted areas of the nervous system,
including the hypothalamus. In this study, we hypothesized that GPR139 could be involved in the regulation of
energy balance and metabolism. In the first part of the study, we confirmed that GPR139 is expressed in the
hypothalamus and particularly in proopiomelanocortin and agouti-related peptide neurons of the mediobasal
hypothalamus. Using a lentivirus with a short-hairpin RNA, we inhibited the expression of GPR139 bilaterally in
the mediobasal hypothalamus of mice. The intervention promoted a 40% reduction in the hypothalamic
expression of GPR139, which was accompanied by an increase in body mass, a reduction in fasting blood glucose
levels, and an increase in insulin levels. In the hypothalamus, inhibition of GPR139 was accompanied by a
reduction in the expression of orexin. As previous studies using a pharmacological antagonist of orexin showed a
beneficial impact on type 2 diabetes and glucose metabolism, we propose that the inhibition of hypothalamic
GPR139 could be acting indirectly through the orexin system to control systemic glucose and insulin. In
conclusion, this study advances the characterization of GPR139 in the hypothalamus, demonstrating its
involvement in the regulation of body mass, blood insulin, and glycemia
Production of a non-stoichiometric Nb-Ti HSLA steel by thermomechanical processing on a Steckel mill.
No full textObtaining high levels of mechanical properties in steels is directly linked to the use of
special mechanical forming processes and the addition of alloying elements during their manufacture. This work presents a study of a hot-rolled steel strip produced to achieve a yield strength
above 600 MPa, using a niobium microalloyed HSLA steel with non-stoichiometric titanium (titanium/nitrogen ratio above 3.42), and rolled on a Steckel mill. A major challenge imposed by
rolling on a Steckel mill is that the process is reversible, resulting in long interpass times, which
facilitates recrystallization and grain growth kinetics. Rolling parameters whose aim was to obtain
the maximum degree of microstructural refinement were determined by considering microstructural
evolution simulations performed in MicroSim-SM® software and studying the alloy through physical
simulations to obtain critical temperatures and determine the CCT diagram. Four ranges of coiling
temperatures (525–550 ◦C/550–600 ◦C/600–650 ◦ C/650–700 ◦C) were applied to evaluate their impact on microstructure, precipitation hardening, and mechanical properties, with the results showing
a very refined microstructure, with the highest yield strength observed at coiling temperatures of
600–650 ◦C. This scenario is explained by the maximum precipitation of titanium carbide observed
at this temperature, leading to a greater contribution of precipitation hardening provided by the
presence of a large volume of small-sized precipitates. This paper shows that the combination of
optimized industrial parameters based on metallurgical mechanisms and advanced modeling techniques opens up new possibilities for a robust production of high-strength steels using a Steckel
mill. The microstructural base for a stable production of high-strength hot-rolled products relies on
a consistent grain size refinement provided mainly by the effect of Nb together with appropriate
rolling parameters, and the fine precipitation of TiC during cooling provides the additional increase
to reach the requested yield strength values
Preparation and sensory evaluation of gels based on silicone copolymers/ acrylic copolymers incorporating different vegetable oils.
No full textFixed vegetable oil is one of the most used plant derivatives for cosmetic application, especially in skin products,
due to its fatty acid composition, which are similar to the skin’s natural components. Therefore, it is important to
study the cosmetic application of new vegetable oils, and how their fatty acid constitution influences the
product’s sensory profile. In this study, topical gel formulations were prepared by cold processing method using
copolymers derived from silicone and acrylic acid incorporating Gueroba (GGE) and Macaúba (GM) vegetable
oils and comparing them to Sweet Almond Oil (GA), considered to have a gold standard. The formulations were
evaluated for physical stability, texture profile, rheology and sensory analysis through the Sorting Test. All gel
formulations allowed the incorporation of vegetable oils and remained stable, without variation in their
organoleptic characteristics; the GM formulation presented the best spreadability performance, with Eimax
3739.8 mm2
. As for texture, the GGE formulation recorded lower Firmness values (4.73 g). Rheological evalu-
ation determined that all formulations showed pseudoplastic behavior, with the presence of thixotropy and
better recovery for GM formulation, which is characteristic of semi-solid formulations for topical use. Sensory
analysis in volunteers indicated that the samples have a similar spreadability profile. The results obtained
indicate that the fatty acids influence the sensory profile of the formulations, being a differential factor in the
sensory performance of cutaneous preparations destined to skin care
Constraining the anomalous coupling of gravitational waves with the double pulsar.
No full textWe revisit the decay of the orbital period in binary systems that occurs due to the emission of
gravitational waves in the context of modifie- gravity models where the coupling Ggw between matter and
on shell gravitons is allowed to differ from the Newton constant GN. Using the most precisely-timed double
neutron star binary system, those of the double pulsar, we constrain the ratio Ggw=GN to the level of 10−4,
improving by two orders of magnitude the present bound on this quantity
Assessing ploidy levels and karyotype structure of the fire ant Solenopsis saevissima Smith, 1855 (Hymenoptera, Formicidae, Myrmicinae).
No full textThe family Formicidae is composed of ants that organize themselves into castes in which every individual has a joint organizational function. Solenopsis Westwood, 1840 is an ant genus with opportunistic and aggressive characteristics, known for being invasive species and stings that cause burning in humans. This genus is particularly difficult to classify and identify since its morphology provides few indications for species differentiation. For this, a tool that has been useful for evolutionary and taxonomic studies is cytogenetics. Here, we cytogenetically studied Solenopsis saevissima Smith, 1855 from Ouro Preto, Minas Gerais, Brazil. We evaluated the occurrence of polyploid cells in individuals and colonies by conventional cytogenetics. A total of 450 metaphases were analyzed and counted. Chromosome counts of individuals and colonies showed varied numbers of ploidies, from n = 16 to 8n = 128. The karyomorphometrical approach allowed determination of the following karyotypes: n = 10 m + 4 sm + 2 st, 2n = 20 m + 8 sm + 4 st, and 4n = 40 m + 16 sm + 8 st. Polyploidy can be found naturally in individuals and colonies and may represent an adaptative trait related to widespread distribution and invasion ability of new habitats
Competition and cooperation relations within the local productive arrangement of Ubá - MG.
No full textO ambiente de negócios contemporâneo se caracteriza pela competitividade e constantes mudanças econômicas, tecnológicas e políticas. Diante de tal fato, surge à necessidade das organizações se unirem na busca por redução de seus custos, aumento de qualidade e ganho de mais força em um mercado globalizado e competitivo. Desta forma, observa-se que as relações interorganizacionais sofreram alterações no tocante ao desenvolvimento de cooperações entre empresas, além da clássica prática isolada de competição. Neste cenário, o presente trabalho apresenta como objetivo o estudo das relações interorganizacionais processadas no arranjo produtivo local de Ubá – MG, focando a questão dual da competição e cooperação. O estudo apresenta caráter qualitativo. Para coleta de dados trabalha-se como entrevista semiestruturada realizada junto a gestores, sendo a interpretação destes dados pautada na técnica de análise de conteúdo. A relevância desta pesquisa encontra-se em termos práticos e teóricos. Em termos práticos, o trabalho pode contribuir para o aprofundamento do conhecimento dos gestores local sobre as relações interorganizacionais processadas no APL que, por vezes, pode estar encoberto. Em termos teóricos, o trabalho gera aportes para o desenvolvimento do arcabouço de conhecimento acerca das relações interorganizacionais permeadas pela competição e cooperação, podendo servir de subsídio para realização de outros estudos deste cunho. A partir do desenvolvimento do estudo, verificou-se que existem relações de cooperação processadas no âmbito do APL, todavia, são focadas na esfera técnico-produtiva. O aumento do escopo destas relações para cooperação em nível tecnológico-estratégica ainda não é uma realidade, enfrentado barreiras de estrutura de coordenação e culturais para sua vigência. Conclui-se, assim, que o APL moveleiro de Ubá deve investir no fortalecimento de sua estrutura de coordenação, pois a partir da mesma será possível trabalhar iniciativas para redução das demais barreiras visando o avanço das relações de cooperação no ambiente em questão.The contemporary business environment is characterized by competitiveness and constant economic, technological, and political changes. In view of this fact, there is a need for organizations to unite in the search for cost reduction, quality increase, and gain more strength in a globalized and competitive market. In this way, it is observed that inter-organizational relations have undergone changes with regard to the development of cooperation among companies, in addition to the classic isolated practice of competition. In this scenario, the present work presents as objective the study of interorganizational relations processed in the local productive arrangement of Ubá - MG, focusing on the dual issue of competition and cooperation. The study presents a qualitative character. For data collection, it is used semi-structured interviews with managers, and the interpretation of these data is based on the technique of content analysis. The relevance of this research is in practical and theoretical terms. In practical terms, the work may contribute to deepen the local managers' knowledge about the inter-organizational relationships processed in the APL, which, at times, may be hidden. In theoretical terms, the work generates contributions for the development of the framework of knowledge about inter-organizational relations permeated by competition and cooperation, and may serve as a subsidy for other studies of this nature. From the development of the study, it was verified that there are relations of cooperation processed in the scope of APL, however, they are focused on the technical-productive sphere. The increase in the scope of these relationships for cooperation at a technological-strategic level is not yet a reality, facing barriers of coordination structure and culture for its validity. We conclude, therefore, that the APL furniture producer from Ubá should invest in the strengthening of its coordination structure, because from this structure it will be possible to work on initiatives to reduce the other barriers aiming at the advancement of cooperative relations in the environment in question
Flowering temporality in dry and wet grasslands from the Chapada do Couto plateau in the Southern Espinhaço Mountain range-MG, Brazil.
No full textA Serra do Espinhaço Meridional apresenta enorme biodiversidade, com vegetação caracterizada pelo predomínio de formações campestres (campos rupestres e campos limpos) intercaladas por formações florestais (capões de mata). O objetivo do trabalho foi avaliar a temporalidade da floração em áreas de campos limpos secos e úmidos (onde ocorrem os ecossistemas de turfeiras), buscando evidenciar a variação temporal de aspectos reprodutivos da vegetação (cor das flores) e o efeito da antropização. Parte das áreas estudadas encontra-se protegida pela unidade de conservação de proteção integral do Parque Estadual do Rio Preto, enquanto as outras áreas são adjacentes, mas fora da unidade de conservação e sujeitas à antropização pelo pastejo e fogo. As áreas foram percorridas mensalmente para coleta de material botânico e registro das espécies em floração, sendo enquadradas em seis categorias de cores (branco, amarelo, laranja, vermelho, rosa/roxo e azul). A área protegida apresentou maior riqueza de espécies (96) que a área não protegida (83), não sendo atingida estabilidade na curva do coletor. A maioria das espécies apresentou eventos anuais de floração, sendo que mais da metade delas foi observada em apenas um mês, com maior concentração na época chuvosa, indicando uma “estação de florescimento” anual. O branco foi a cor predominante nas flores (principalmente Asteraceae e Eriocaulaceae), seguida do rosa/ roxo (Melastomataceae) e amarelo (Asteraceae e Xyridaceae). Enquanto as cores associadas a visitantes mais generalistas (branco e amarelo) apresentaram floração mais marcada pela sazonalidade, as flores associadas a sistemas mais especializados (vermelho e laranja) apresentaram floração aparentemente mais contínua ao longo do tempo.The Southern Espinhaço mountain range harbors enormous biodiversity, with a vegetation typically dominated by grassland formations (campos rupestres and campos limpos) speckled with forest formations (capões de mata). This study aimed to evaluate the flowering temporality in areas of dry and wet (where peatlands occur) campos limpos, in order to highlight the temporal variation in plant reproductive characteristics (flower collor) and the effect of anthropization. Some of the studied sites were protected by the Rio Preto State Park, a nature conservation site of full protection, whereas the other sites were adjacent, but outside the conservation unit and subject to anthropization by grazing and fires. The sites were monthly evaluated for collecting botanical material and registering flowering species, being placed in six color categories (white, yellow, orange, red, pink/purple and blue). The protected area presented higher species richness (96) than the unprotected sites (83), although sampling stability was not reached in the collector curves. Most species presented annual flowering events, with more than half of the species being observed in a single month, concentrated in the rainy season, indicating an annual “flowering season”. White was the dominant collor (especially in Asteraceae and Eriocaulaceae), followed by pink/purple (Melastomataceae) and yellow (Asteraceae and Xyridaceae). While the collors associated with generalist pollinators (white and yellow) presented a markedly seasonal flowering, the flowers associated to more specialized systems (red and orange) apparently presented a more continuous flowering over time
Mathematics curriculum materials : state of knowledge of Brazilian research.
No full textObjetivo do artigo situa-se em identificar a pesquisa brasileira que tem os materiais
curriculares como tema de investigação e refletir sobre os seus resultados. Para tanto, por meio
da abordagem qualitativa e de caráter bibliográfico, realizamos um estudo do conhecimento. O
corpus textual aqui tomado como objeto de estudo é composto por 25 pesquisas distribuídas
entre teses e dissertações compreendidas no espaço temporal de 2013 a 2019. Os resultados
indicam que a comunidade acadêmica brasileira de Educação Matemática tem buscado a
compreensão mais acurada de aspectos da relação estabelecida entre professores e materiais
curriculares, diminuindo sua intensidade sobre as características físicas dos materiais
curriculares. O estudo acerca dessa relação tem se mostrado relevante e passível de outras
investigações de modo que os conhecimentos deste campo continuem avançando.The purpose of the article is to identify Brazilian research that has curriculum
materials as a research topic and to reflect on its results. Therefore, through a qualitative
approach and of a bibliographic character, we carried out a study of the knowledge. The textual
collection here was taken as a study object is compounded by 25 researches spread between
thesis and dissertations in the temporal space in between 2013 to 2019. The results point that
the academic Brazilian community of Mathematical Education has searched for a more accurate
comprehension of the relationship aspects between teachers and curriculum materials,
decreasing its intensity over other physical characteristics of curriculum materials. The study
about this relationship has been showing relevant and subject to another investigations so that
the knowledge of this field continue to progress
Bioleaching of two diferent chalcopyrite ores in chloride media.
No full textChalcopyrite is the most abundant copper mineral and its bioleaching has been the subject of several studies due to its refractory nature when submitted to hydrometallurgical processes. Moreover, the growing worldwide demand for copper requires the processing of low-grade ores or mining tailings for which hydrometallurgical processes are a cost-efective alternative. New approaches have shown that the use of chloride ions in chalcopyrite leaching can positively contribute to its dissolution. In this regard, the present work assessed the bioleaching of two chalcopyrite ores—containing 0.34% Cu (copper ore 1) and 1.79% Cu (copper ore 2) by the extreme thermophilic archaea Sulfolobus acidocaldarius. In addition, the efect of diferent NaCl concentrations (0.25 − 1.0mol/L) on copper extraction were investigated. In the experiments with the copper ore 1, the copper extractions were higher in the abiotic experiments (from 83 to 90%) than in the biotic experiments (62–80%) for all NaCl concentrations investigated. On the other hand, the experiments with the copper ore 2 showed similar results (around 83% Cu extractions) in all abiotic tests carried out in the presence of chloride and also in the biotic experiments with 0.25 and 0.50mol/LNaCl concentrations. However, a 97% copper extraction was observed in the biotic experiment carried out with 1.0mol/LNaCl. Regardless of the type of ore, the lowest copper dissolutions (less than 55%) were obtained in the experiments in the absence of both microorganism and chloride. The XRD analyses of the solid residues of the bioleaching experiments did not reveal the presence of Fe(III)-precipitates such as jarosite