Direct in situ observation of the electron-driven synthesis of Ag filaments on α-Ag2 WO4 crystals

In this letter, we report, for the first time, the real-time in situ nucleation and growth of Ag filaments on α-Ag2 WO4 crystals driven by an accelerated electron beam from an electronic microscope under high vacuum. We employed several techniques to characterise the material in depth. By using these techniques combined with first-principles modelling based on density functional theory, a mechanism for the Ag filament formation followed by a subsequent growth process from the nano-to micro-scale was proposed. In general, we have shown that an accelerated electron beam from an electronic microscope under high vacuum enables in situ visualisation of Ag filaments with subnanometer resolution and offers great potential for addressing many fundamental issues in materials science, chemistry, physics and other fields of science.

Possibilidades e limites da aprendizagem baseada em problemas no ensino médio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise das concepções de professores de biologia em formação inicial acerca da relação entre ciência e valores

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aspectos formativos da experiência com questões sociocientíficas no ensino de ciências sob uma perspectiva crítica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A abordagem de questões sociocientíficas na formação continuada de professores de ciências: contribuições e dificuldades

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Enfoque CTSA no ensino de astronomia: uma investigação de possibilidades por meio da astronáutica

Pós-graduação em Educação para a Ciência - FC

Non-centrosymmetric crystals of new N-benzylideneaniline derivatives as potential materials for non-linear optics

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Concepciones de futuros profesores de biología, brasileros y portugueses sobre valores eticos de la ciencia

One of the science education objective, based on relationships between science, technology, society and environment (STSE) is, to form citizens capable on evaluating and taking decisions about the scientific advances impact on society and environment. In a two-way perspective, understand relationships between STSE, provides a vision of science as a human construction and therefore fallible, changeable and not neutral. In this study, we present some results from a comparative study on the influence of ethical conceptions of the nature of science, in two groups of future biology teachers, one from Brazil and, another one from Portugal. For data collection we constructed an attitude scale of Likert-type, which was validated mathematically and semantically. Results shows strong influence of social values, as in transgenic products, where the students’ ideas varied according to the ethical discussions more present in each country.

Alfabetização científica em nível médio e a preparação dos cidadãos para o processo de tomada de decisões

The concept of scientific literacy nowadays is permeated by principles eventually inconsistent. Development of cognitive skills, preparation for continuing studies in higher education, preparation for working life and the strengthening of citizenship are some of the competing goals of science education. In respect of Science, Technology, Society and Environment (STSE) Education, the politics of science should be properly taken into account by science education. This paper examines the concept of scientific literacy in the context of STSE Education and points to why and how physics education in high school curriculum should address topics of energy consumption and production in order to provide the background necessary to assess public policies of science, technology and innovation, in particular the Decennial Plan for Expansion of Energy 2020, subjected to public consultation by the Brazilian Ministry of Mines and Energy in 2011.

Possibilidades e limitações da prática do professor na experiência com a temática energia e desenvolvimento humano no ensino de ciências

Reflections on the Movement STSE, in basic education, have pointed to the introduction of discussions involving the socio-scientific issues, as a way of organization and development of forming processes in science classes. In this sense, the research that we developed sought to bring to physics classes of basic education, the discussions surrounding the relationship between science, technology, society and environment issues related to production and access to electricity and human development. In order to interpret formative aspects of this approach was achieved through a short course. Thus, we discuss in this paper, the discourse of students and a professor of physics who participated in this short course. Therefore, we seek in discourse analysis, reflection on this practice, which has limitations such as lack of recognition of this type of training status by the students as well as possibilities represented by the establishment of training spaces that contribute to the discussion of socio-scientific issues.

Combinatorial-topological framework for the analysis of global dynamics

We discuss an algorithmic framework based on efficient graph algorithms and algebraic-topological computational tools. The framework is aimed at automatic computation of a database of global dynamics of a given m-parameter semidynamical system with discrete time on a bounded subset of the n-dimensional phase space. We introduce the mathematical background, which is based upon Conley's topological approach to dynamics, describe the algorithms for the analysis of the dynamics using rectangular grids both in phase space and parameter space, and show two sample applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4767672]

Seismic performance case study of bridge pile cap foundation

The purpose of this report is to build a model that represents, as best as possible, the seismic behavior of a pile cap bridge foundation by a nonlinear static (analysis) procedure. It will consist of a reproduction of a specimen already built in the laboratory. This model will carry out a pseudo static lateral and horizontal pushover test that will be applied onto the pile cap until the failure of the structure, the formation of a plastic hinge in the piles due to the horizontal deformation, occurs. The pushover test consists of increasing the horizontal load over the pile cap until the horizontal displacement wanted at the height of the pile cap is reached. The output of this model will be a Skeleton curve that will plot the lateral load (kN) over the displacement (m), so that the maximum movement the pile cap foundation can reach before its failure can be calculated. This failure will be achieved when the load at that specific shift is equal to 85% of the maximum. The pile cap foundation finite element model was based on pile cap built for a laboratory experiment already carried out by the Master student Deming Zhang at Tongji University. Two different pile caps were tested with a difference in height above the ground level. While one has 0:3m, the other rises 0:8m above the ground level. The computer model was calibrated using the experimental results. The pile cap foundation will be programmed in a finite element environment called OpenSees (Open System for Earthquake Engineering Simulation [28]). This environment is a free software developed by Berkeley University specialized, as it name says, in the study of earthquakes and its effects on structures. This specialization is the main reason why it is being used for building this model as it makes it possible to build any finite element model, and perform several analysis in order to get the results wanted. The development of OpenSees is sponsored by the Pacific Earthquake Engineering Research Center through the National Science Foundation engineering and education centers program. OpenSees uses Tcl language to program it, which is a language similar to C++.

Possibilidades de enfoque CTS para o ensino superior de química: proposta de uma abordagem para ácidos e bases

Scientific education has been passing by redefinitions, contestations and new contributions from the research on science teaching. One contribution is the idea of science and technology literacy, allowing the citizens not only knowing science but also understand aspects on the construction and motivation of scientific and technological research. In accordance with this idea, there is the Science-Technology-Society (STS) studies which, since the 1970s, has been contributing for science teaching and learning according to the comprehension of the relationships with society in the Western countries of the North. In Brazil, this approach began to gain projection from the 1990s when the first essays on the theme were published. Currently, there is a clear influence of this approach on the national curriculum guidelines, especially for the area of Natural Sciences, and also on the textbooks chosen by the High School National Program (Programa Nacional do Ensino Médio). However, there seems to be a gap in relation to the discussion on the specific curricular component seen in college on this approach. Thus, this study aims at adopting the approach STS, face to the preparation of complimentary educational material on acid and bases concepts studied in the course of General Chemistry of the Natural Sciences graduation program. To this end, it was performed a bibliographical research aiming at making the state-of-the-art in in these concepts in specific literature to science teaching. It is divided in two stages: systematic study (with sixteen journals chosen according to Qualis-Capes and an unsystematic study with direct search in databases and references in the papers of the systematic study. The studies had their content analyzed and the categories chosen a priori were the level of education, the acid-base theory adopted, and the strategy/theoretical frame of reference adopted. A second stage aimed at identifying attitudes and beliefs on STS (Science-Technology-Society) and CSE (Chemistry-Society-Environment) of students in the teacher and technologist training course in three diferent institutions: UTFPR, UFRN and IFRN. In this study, it was used two questionnaires, composed of a Likert scale, semantic differential scale and open questions. The quantitative data reliability was estimated through Cronbach’s alpha method, and tha data were treated according to classic statistics, using the mean as the centrality measures, and the mean deviation as dispersion. The qualitative data were treated according to the content analysis with categories taken from the reading of answers. In the third stage, it was analyzed the presence of STS and CSE content in chapters on acid and bases concepts of nine General Chemistry textbooks, frequently used in graduation programs in public institutions of the state of Rio Grande do Norte. The results showed that there are few proposals of acid and bases teaching, and they are generally aimed at High School or at instrumentation for teaching courses, and no course for General Chemistry. The student’s attitudes and beliefs show the presence of a positivist point of view based on the concept of Science and Technology neutrality and the salvation of its mediation. The books analysis showed just a few content on STS and CSE are found in the studied chapters, and they are generally presented disjointedly in relation to the rest of the main text. In the end, as suggestion to solve the absence of proposals STS in General Chemistry books, as well as the student’s positivist attitudes, it was developed some educational material to be used in the course of General Chemistry at College. The material is structured to introduce a historical view of the concepts preparation, present the use of materials, the industrial and technological processes, and social and environmental consequences of this activities

Preferred semantics as Socratic discussion

Funding For M.C., the major part of the work on this article was carried out while he was affiliated with the Interdisciplinary Centre for Security, Reliability and Trust at the University of Luxembourg. His research was supported by the National Research Fund, Luxembourg (LAAMI project), as well as by the Engineering and Physical Sciences Research Council (EPSRC, UK), grant ref. EP/J012084/1 (SAsSY project). For S.V., the major part of the work on this article was carried out while he was affiliated with the Computer Science and Communication Research Unit at the University of Luxembourg. He worked on this article during the tenure of an ERCIM Alain Bensoussan Fellowship Programme, which is supported by the Marie Curie Co-funding of Regional, National and International Programmes (COFUND) of the European Commission. During this time, he was also funded by the National Research Fund, Luxembourg. When finishing the work on this article, he was a CRNS researcher affiliated with CRIL

Preferred semantics as Socratic discussion

Funding For M.C., the major part of the work on this article was carried out while he was affiliated with the Interdisciplinary Centre for Security, Reliability and Trust at the University of Luxembourg. His research was supported by the National Research Fund, Luxembourg (LAAMI project), as well as by the Engineering and Physical Sciences Research Council (EPSRC, UK), grant ref. EP/J012084/1 (SAsSY project). For S.V., the major part of the work on this article was carried out while he was affiliated with the Computer Science and Communication Research Unit at the University of Luxembourg. He worked on this article during the tenure of an ERCIM Alain Bensoussan Fellowship Programme, which is supported by the Marie Curie Co-funding of Regional, National and International Programmes (COFUND) of the European Commission. During this time, he was also funded by the National Research Fund, Luxembourg. When finishing the work on this article, he was a CRNS researcher affiliated with CRIL