3,085 research outputs found

    Dynamical demixing of a binary mixture under sedimentation

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    We investigate the sedimentation dynamics of a binary mixture, the species of which differ by their Stokes coefficients but are identical otherwise. We analyze the sedimentation dynamics and the morphology of the final deposits using Brownian dynamics simulations for mixtures with a range of sedimentation velocities of both species. We found a threshold in the sedimentation velocities difference above which the species in the final deposit are segregated. The degree of segregation increases with the difference in the Stokes coefficients or the sedimentation velocities above the threshold. We propose a simple mean-field model that captures the main features of the simulated deposits

    Enhanced propagation of motile bacteria on surfaces due to forward scattering

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    How motile bacteria move near a surface is a problem of fundamental biophysical interest and is key to the emergence of several phenomena of biological, ecological and medical relevance, including biofilm formation. Solid boundaries can strongly influence a cell's propulsion mechanism, thus leading many flagellated bacteria to describe long circular trajectories stably entrapped by the surface. Experimental studies on near-surface bacterial motility have, however, neglected the fact that real environments have typical microstructures varying on the scale of the cells' motion. Here, we show that micro-obstacles influence the propagation of peritrichously flagellated bacteria on a flat surface in a non-monotonic way. Instead of hindering it, an optimal, relatively low obstacle density can significantly enhance cells' propagation on surfaces due to individual forward-scattering events. This finding provides insight on the emerging dynamics of chiral active matter in complex environments and inspires possible routes to control microbial ecology in natural habitats

    Estudo da dinâmica da floresta manejada no projeto de manejo florestal comunitário do PC Pedro Peixoto na Amazônia Ocidental.

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    Neste trabalho são apresentados resultados do estudo da dinâmica da floresta em um sistema de manejo florestal voltado para a pequena propriedade. O sistema prescreve ciclo de corte de 10 anos e taxa de corte de 10 m3.ha-1 e tração animal para o arraste. O crescimento da floresta de 1 m3.ha-1.ano-1 foi compatível com o ciclo e taxa de corte adotados. Os danos causados pela exploração representaram 5 % da área basal total, e a taxa de mortalidade quatro anos após a exploração foi 3,2 %

    Avaliação experimental de ligações aparafusadas em pinho bravo e câmbala

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    No presente trabalho avaliaram-se experimentalmente ligações aparafusadas, aferindo a aplicabilidade do Eurocódigo 5 em relação às duas espécies de madeira seleccionadas, Câmbala (Milícia excelsa) e Pinho bravo (Pinus pinaster). Como ligador, utilizaram-se parafusos autoperfurantes HBS da Rotho Blaas. Para além do ensaio de ligações aparafusadas em corte simples, a campanha experimental teve como objectivo avaliar os vários mecanismos de resistência considerados pela metodologia de cálculo sugerida pelo Eurocódigo 5 para este género de ligações, nomeadamente: a) resistência ao arrancamento do parafuso do elemento que recebe a ponta; b) resistência ao atravessamento da cabeça do parafuso; c) esmagamento localizado da madeira; e d) flexão do parafuso. Os resultados experimentais demonstram a fiabilidade da metodologia de cálculo proposta pelo Eurocódigo 5 e atestam o bom comportamento garantido por ligações aparafusadas com parafusos HBS utilizando Pinho bravo e Câmbala.In the present study, screwed connections have been experimentally evaluated, checking the applicability of Eurocode 5 for the two species of wood selected, Iroko (Milícia excelsa) and Maritime pine (Pinus pinaster). As connector, self-drilling screws of HBS Roth Blaas have been used. Single shear screwed connections have been testes moreover, the experimental campaign aimed to evaluate various mechanisms of resistance considered by the calculation method suggested by Eurocode 5 for this kind of connections, including: a) axial withdrawal capacity of the screw, b) pull through parameter for screws, c) local embedment of wood, and d) yield moment of the screw. The experimental results demonstrate the reliability of the calculation methodology proposed by the Eurocode 5 and certify the good behavior guaranteed by screwed connections with HBS screws in the case of Maritime pine and Iroko

    GRAPP & IVAPP 2012: Proceedings of the International Conference on Computer Graphics Theory and Applications and International Conference on Information Visualization Theory and Applications

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    This book contains the proceedings of the International Conference on Computer Graphics Theory and Applications (GRAPP 2012) and of the International Conference on Information Visualization Theory and Applications (IVAPP 2011) which were organized and sponsored by the Institute for Systems and Technologies of Information, Control and Communication (INSTICC). We hope that the proceedings here published, demonstrate new and innovative solutions, and highlight technical problems in each field that are challenging and worthwhile. Thus, GRAPP and IVAPP were organized to promote a discussion forum between researchers, developers, manufactures and end-users, about the conferences research topics and to establish guidelines in the developing of more advanced solutions. We received a high number of paper submissions for this edition of GRAPP, 116 in total, with contributions from all five continents which attest to the success and global dimension of GRAPP. To evaluate each submission, we used a double-blind evaluation method and each paper was reviewed by at least two experts from the International Program Committee. In the end, 20 papers were selected for publication as full papers, 35 papers were accepted for short presentation and 23 were accepted for poster presentation. The result was an oral-paper acceptance ratio of 47% and a high-quality program that is attractive to experts from Computer Graphics area. A high number of paper submissions for this edition of IVAPP was also received, 66 in total, with contributions from all five continents which attest to the success and global dimension of IVAPP. 12 papers were selected for publication as full papers, 7 papers were accepted for short presentation and 15 were accepted for poster presentation. The result was an oral-paper acceptance ratio of 29% and a high-quality program that is attractive to experts from Information Visualization area. We hope that these Conference Proceedings, submitted for indexation by Thomson Reuters Conference Proceedings Citation Index, INSPEC, DBLP and EI, may help the Computer Graphics community to find interesting research work. Furthermore, a short list of presented papers will be selected to be expanded into a forthcoming book of VISIGRAPP Selected Papers to be published by Springer during 2012. Moreover, the conference also featured a number of keynote lectures delivered by internationally well known experts thus contributing to increase the overall quality of the conference and to provide a deeper understanding of the conference interest fields. In order to promote the development of professional networks the organizing committee has prepared a Conference Dinner in the evening of February 25th. We hope that you enjoy this exciting conference and have an unforgettable stay in the beautiful city of Rome, Italy. Finally, we would like to express our thanks, first of all, to the authors of the technical papers, whose work and dedication make possible to put together a program that we believe very exciting and of high technical quality. Next, we would like to thank all the members of the program committee and auxiliary reviewers, who helped us with their expertise and time. We would also like to thank the invited speakers for their invaluable contribution and for sharing their vision in their talks. Special thanks should be addressed to the INSTICC Steering Committee whose invaluable work made possible this event. We wish you all an exciting conference and an unforgettable stay in Rome, Italy. We hope to meet you again for the next edition of GRAPP and IVAPP, details of which will be shortly available at http://www.grapp.visigrapp.org and http://www.ivapp.visigrapp.org

    Knowledge and attitude towards the gradual reduction of salt in bread – an online survey

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    Aim: Assess knowledge and attitude towards the gradual reduction of salt in bread and the potential impact on eating habits of children (6-18 years) and their families, as part as a Health Impact Assessment pilot study.N/

    Crescimento e competição do pinho-bravo em remanescente de floresta natural em Colombo, PR .

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    Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos
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