Spectral density of dense random networks and the breakdown of the Wigner semicircle law

Although the spectra of random networks have been studied for a long time, the influence of network topology on the dense limit of network spectra remains poorly understood. By considering the configuration model of networks with four distinct degree distributions, we show that the spectral density of the adjacency matrices of dense random networks is determined by the strength of the degree fluctuations. In particular, the eigenvalue distribution of dense networks with an exponential degree distribution is governed by a simple equation, from which we uncover a logarithmic singularity in the spectral density. We also derive a relation between the fourth moment of the eigenvalue distribution and the variance of the degree distribution, which leads to a sufficient condition for the breakdown of the Wigner semicircle law for dense random networks. Based on the same relation, we propose a classification scheme of the distinct universal behaviors of the spectral density in the dense limit. Our theoretical findings should lead to important insights on the mean-field behavior of models defined on graphs

Analytic solution of the resolvent equations for heterogeneous random graphs : spectral and localization properties

The spectral and localization properties of heterogeneous random graphs are determined by the resolvent distributional equations, which have so far resisted an analytic treatment. We solve analytically the resolvent equations of random graphs with an arbitrary degree distribution in the high-connectivity limit, from which we perform a thorough analysis of the impact of degree fluctuations on the spectral density, the inverse participation ratio, and the distribution of the local density of states (LDOSs). For random graphs with a negative binomial degree distribution, we show that all eigenvectors are extended and that the spectral density exhibits a logarithmic or a power-law divergence when the variance of the degree distribution is large enough. We elucidate this singular behaviour by showing that the distribution of the LDOSs at the centre of the spectrum displays a power-law tail controlled by the variance of the degree distribution. In the regime of weak degree fluctuations the spectral density has a finite support, which promotes the stability of large complex systems on random graphs

A ALFABETIZAÇÃO ECOLÓGICA NAS POLÍTICAS PÚBLICAS EDUCACIONAIS E AMBIENTAIS: FUNDAMENTO TEÓRICO E CONSTITUCIONAL

A educação ambiental é importante protagonista da construção da consciência ecológica e do desenvolvimento de uma compreensão integrada do meio ambiente, firmada nos princípios da ecologia profunda. A afirmação da democracia ambiental, bem como de uma cultura preservacionista passa pela correta leitura e consideração dos princípios constitucionais ambientais e pela aplicação irrestrita da concepção da alfabetização ecológica. Desse modo, a alfabetização ecológica, como prática pedagógica multidisciplinar, baseada na participação, emerge como plataforma de auxílio à superação da fragmentaçãodo saber, do cartesianismo e da filosofia da consciência, que separa sujeito e objeto, facilitando a compreensão, por meio dos princípios da ecologia, de como viver de maneira sustentável, amparando as políticas públicas educacionais e oconstitucionalismo ambiental.

Birds of the Reserva Biológica do Mato Grande and surroundings, Rio Grande do Sul, Brazil

The Reserva Biológica do Mato Grande encompasses 5,161 hectares of wetlands, restinga forests and grasslands in southern Brazil. Aiming to assemble a list of bird species occurring in the reserve, we carried out 21 monthly expeditions from July 2007 to March 2009 and an additional visit on October 2014, totaling 341 hours of sampling. We additionally searched for records in online databases and museums. In total, 211 species of birds were found, compared to 223.83 (SD = 3.88) and 214.68 (SD = 4.71) species respectively predicted through Jackknife 2 and Chao 2 estimations. Plegadis chihi was the most abundant bird roosting in the reserve. The area is important for the conservation of Circus cinereus, Spartonoica maluroides, Limnoctites rectirostris and Sporophila palustris, which are considered threatened or near-threatened in state, national and/or global levels. We emphasize the urgent need of implementing the Reserva Biológica do Mato Grande in order to conserve the regional avifauna

Contribuições das pesquisas em ensino de ciências e matemática atinentes à produção escrita

Resumo: Neste artigo apresentamos resultados de uma pesquisa de caráter bibliográfico, com a intenção de conhecer as investigações atinentes à produção escrita (PE) presentes em trabalhos acadêmicos da área de Ensino de Ciências e Matemática. Com o intuito de identificar em que contexto de investigação a produção escrita foi empregada e como os autores desses trabalhos compreendem o termo produção escrita, utilizamos os procedimentos metodológicos da Análise de Conteúdo para selecionar e analisar 65 Dissertações e 17 Teses. Como resultados, evidenciamos que as pesquisas em Ensino de Ciências e Matemática utilizaram a produção escrita como instrumento de aprendizagem ou como instrumento formativo, uma vez que objetivaram investigar os conhecimentos mobilizados pelos sujeitos que realizaram a PE ou estiveram relacionadas à aprendizagem docente dos sujeitos que analisaram ou realizaram a PE. Constatamos, também, que a produção escrita apresentada nesses trabalhos acadêmicos consistiu em registros escritos, desenhos, representações geométricas, colagens e resoluções matemáticas.Palavras-chave: Produção escrita; Pesquisas acadêmicas; Ensino de Ciências e Matemática. Contributions of research in science and mathematics teaching related to writtten productionAbstract: In this article, we present results of a bibliographic research with the intention of knowing the investigations related to the written production in academic research in the area of Science and Mathematics Teaching. In order to identify in which research context was employed the written production and how the authors of these works understood written production, we used the methodological procedures of Content Analysis to select and analyze 65 Dissertations and 17 Theses. As a result, we found that research in Science and Mathematics Teaching used written production as a learning tool or as a training tool, since they investigated the knowledge mobilized by the subjects who carried out the written production, or were related to the teaching learning of the subjects who analyzed or carried out the written production. We also verified that the written production presented in these academic works consisted of written records, drawings, geometric representations, collages and mathematical resolutions.Keywords: Written production; Academic research; Science and Mathematics Teaching.

A study of the written production of the high school students on Science Questions of PISA

Pesquisas têm ressaltado a necessidade de uma educação em Ciências em que os indivíduos sejam capazes de desenvolver ideias e maneiras científicas de pensar, resolver problemas e tomar decisões na vida pessoal, cívica e profissional, enfatizando a importância do Letramento Científico. Em meio a esse contexto, neste artigo apresenta-se uma investigação da produção escrita de estudantes do Ensino Médio em três questões de Ciências do PISA que abordam conceitos químicos das temáticas Ozônio, Brilho Labial e Massa de Pão, respectivamente, a fim de evidenciar algumas tendências de respostas, possíveis dificuldades apresentadas e conhecimentos científicos mobilizados para a resolução das questões. Por meio dos procedimentos da Análise de Conteúdo, constatou-se que a maioria das produções escritas investigadas ressaltou possíveis dificuldades dos estudantes quanto à utilização de linguagem científica para explicar/justificar fenômenos químicos e/ou lidar corretamente com as informações das questões para produzir argumentos e conclusões fundamentados em evidências científicas. Nesse sentido, verificou-se que as dificuldades dos estudantes podem estar relacionadas à não compreensão de alguns aspectos do Letramento Científico como determinados conceitos científicos e alguns processos de investigação.Researches highlight the demand for a Science education in which individuals are able to develop scientific ideas and ways of thinking, solving problems, and making decisions in their personal, civic, and professional lives, emphasizing the importance of Scientific Literacy. In this context, this article presents an investigation of the written production of high school students on three PISA Science questions that address chemical concepts, concerning the themes of Ozone, Lip Gloss, and Bread Dough. The aim is to highlight possible answers trends, difficulties, and scientific knowledge mobilized to solve the proposed questions. By applying the Content Analysis procedures, it was found that most of the investigated written productions highlight possible difficulties of students regarding the use of scientific language to explain/justify chemical phenomena. Another difficulty dealing correctly with the questions information to produce arguments and conclusions based on scientific evidence. In this sense, the student difficulties may be related to the misunderstanding of some aspects of Scientific Literacy, such as certain scientific concepts and some investigation processes

Cancer in the social representations of caregivers: implications for care

Objective: Identify the social representations of caregivers of cancer for patients with no chance of cure and analyze their implications for care. Method: This is a qualitative research based on the Theory of Representations. Results: In thematic content analysis fell into two categories: The discovery of the other necessary care and generating two subunits: Limitations and Dependencies of the patient and participation in care; The relationship care, caregiver and patient that generated two subunits: The suffering of caregivers and support, the comfort and hope the caregiver. Conclusion: Is necessary that the nurse promotes strategies that facilitate the involvement of caregivers and the family in caring