Predição da configuração de sombras de árvores em pastagens para bovinos

São propostas equações para a determinação da orientação, comprimento e área da sombra projetada por árvores destinadas ao plantio em pastagens para bovinos, considerando o local, a época do ano e a hora do dia. As equações abrangem árvores com os seguintes formatos de copa: esférica, lentiforme, cilíndrica, elipsóide, cônica e cônica invertida. Um exemplo é apresentado, discutindo-se a aplicação no sombreamento de pastagens.

3D semantic models for dental education

This paper explores the benefits of using immersive and interactive virtual reality environments to teach Dentistry. We present a tool for educators to manipulate and edit virtual models. One of the main contributions is that multimedia information can be semantically associated with parts of the model, through an ontology, enriching the experience; for example, videos can be linked to each tooth demonstrating how to extract them. The use of semantic information gives a greater flexibility to the models, since filters can be applied to create temporary models that show subsets of the original data in a human friendly way. We also explain how the software was written to run in arbitrary multi-projection environments. © 2011 Springer-Verlag.

Teacher-learning process based on an immersive and interactive environment

This paper explores the benefits of using immersive and interactive multiprojection environments (CAVE) to visualize molecules, and how it improves users’ understanding. We have proposed and implemented a tool for teachers to manipulate molecules and another to edit molecules and assist students at home. The contribution of the present research project are these tool that allows investigating structures, properties and dynamics of a molecular system which are extremely complex and comprises millions of atoms. The experience is enriched through multimedia information associated with parts of the model; for example, videos and text can be linked to specific molecule, demonstrating some detail. This solution is based on a teaching-learning process.

Vacuumless kink systems from vacuum systems: An example

Some years ago, Cho and Vilenkin, introduced a model which presents topological solutions, despite not having degenerate vacua as is usually expected. Here we present a new model with topological defects, connecting degenerate vacua but which in a certain limit recovers precisely the one proposed originally by Cho and Vilenkin. In other words, we found a kind of parent model for the so called vacuumless model. Then the idea is extended to a model recently introduced by Bazeia et al. Finally, we trace some comments the case of the Liouville model.

Bothrops moojeni myotoxin-II, a Lys49-phospholipase A(2) homologue: An example of function versatility of snake venom proteins

MjTX-II, a myotoxic phospholipase A(2) (PLA(2)) homologue from Bothrops moojeni venom, was functionally and structurally characterized. The MjTX-II characterization included: (i) functional characterization (antitumoral, antimicrobial and antiparasitic effects); (ii) effects of structural modifications by 4-bromophenacyl bromide (BPB), cyanogen bromide (CNBr), acetic anhydride and 2-nitrobenzenesulphonyl fluoride (NBSF); (iii) enzymatic characterization: inhibition by low molecular weight heparin and EDTA; and (iv) molecular characterization: cDNA sequence and molecular structure prediction. The results demonstrated that MjTX-II displayed antimicrobial activity by growth inhibition against Escherichia coli and Candida albicans, antitumoral activity against Erlich ascitic tumor (EAT), human breast adenocarcinoma (SK-BR-3) and human T leukemia cells (JURKAT) and antiparasitic effects against Schistosoma mansoni and Leishmania spp., which makes MjTX-II a promising molecular model for future therapeutic applications, as well as other multifunctional homologous Lys49-PLA(2)S or even derived peptides. This work provides useful insights into the structural determinants of the action of Lys49-PLA2 homologues and, together with additional strategies, supports the concept of the presence of others bioactive sites distinct from the catalytic site in snake venom myotoxic PLA(2)s. (c) 2005 Elsevier B.V. All rights reserved.

The 5S rDNA family evolves through concerted and birth-and-death evolution in fish genomes: an example from freshwater stingrays

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Reduction of a native fish fauna by alien species: an example from Brazilian freshwater tropical lakes

The consequences of introducing Cichla cf. monoculus Spix & Agassiz, Astronotus ocellatus (Agassiz) and Pygocentrus nattereri Kner into lakes in the River Doce basin, Brazil, on richness, diversity and efficiency of aquatic macrophytes as natural refugia to native fishes was investigated. Samples were taken from lakes with and without alien fishes in areas with and without aquatic macrophytes. The presence of alien fishes reduced richness and diversity of the native fish community. The refugia function, which could be attributed to the clustering of aquatic macrophytes, does not exist in these lakes probably because the alien fishes exploit such habitats for reproduction. Since introductions threaten the native fish diversity of the region, studies on regional dispersion and factors that minimise the spread of alien fishes are needed.

Anting behavior by the White-bearded Manakin (Manacus manacus, Pipridae): an example of functional interaction in a frugivorous lekking bird

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Instability zones for satellites of asteroids: The example of the (87) Sylvia system

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

When decisions on homologous structures cause ambiguous taxa relationships: the Neomorphinae (Aves, Cuculidae) example

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tectonic history and the biogeography of the freshwater fishes from the coastal drainages of eastern Brazil: an example of faunal evolution associated with a divergent continental margin

As drenagens costeiras do leste do Brasil correspondem a áreas de grande significado biogeográfico, apresentando um alto grau de endemismo em sua fauna de peixes. Padrões filogenéticos sugerem uma relação próxima entre os rios que correm para o Atlântico a os adjacentes das terras altas do escudo cristalino. Entretanto, pouco tem sido dito sobre a dinâmica dos processos geológicos relacionados aos eventos cladogenéticos entre estas áreas. Padrões de distribuição e filogenéticos sugerem uma íntima associação com a história geológica da margem continental passiva da América do Sul, desde o Cretáceo aos dias atuais. Soerguimentos macrodômicos, rifteamento, movimentos verticais entre blocos falhados e o recuo erosivo da margem leste sul-americana são considerados como as principais forças geológicas atuando sobre a distribuição da ictiofauna de água doce nestas áreas. A atividade tectônica associada à ruptura do Gondwana e separação da América do Sul e África criou seis megadomos que são responsáveis por configurar a maior parte do atual curso das principais bacias hidrográficas do escudo cristalino. Com exceção das bacias localizadas às margens de tais megadomos, estes rios desenvolveram longos e sinuosos circuitos sobre o antigo escudo cristalino brasileiro antes de desaguarem no então recentemente aberto Oceano Atlântico. Eventos cladogenéticos iniciais entre drenagens de terras altas do escudo cristalino e tributários do Atlântico podem estar associados com processos vicariantes desta fase inicial, e alguns táxons antigos, basais, grupos-irmão de táxons muito inclusivos e de ampla distribuição são encontrados nestas bacias hidrográficas. Mais tarde, a denudação erosiva generalizada resultou em um ajuste isostático da margem leste da plataforma. Tal ajuste, concomitantemente a reativações de antigas zonas de falha, resultou em movimentos verticais entre blocos falhados, dando origem, no sudeste do Brasil, a bacias tafrogênicas. Tais bacias, como a de Taubaté, São Paulo, Curitiba e Volta Redonda, entre outras, capturaram drenagens e fauna de terras altas adjacentes. Os peixes fósseis da Formação Tremembé (Eoceno-Oligoceno da Bacia de Taubaté) exemplificam este processo. Outros sistemas tafrogênicos de idade Terciária foram também identificados em outros segmentos da margem continental Atlântica, como na Província Borborema, no NE do Brasil, com marcada influência sobre o padrão de drenagem. Ao mesmo tempo, o recuo erosivo da margem leste da plataforma capturou sucessivamente rios de planalto, os quais se tornaram tributários atlânticos, evoluindo associados aos principais sistemas de falha. A natureza continuada destes processos explica os padrões filogenéticos e de distribuição miscigenados entre os tributários atlânticos e as terras altas do escudo cristalino adjacente, especialmente na margem sudeste do continente, representados por sucessivos, cada vez menos inclusivos, grupos irmãos, associados a eventos cladogenéticos desde o final do Cretáceo ao presente.

Approximate analytical states of a polynomial potential: an example of symmetry restoration

An approximate analytical expression for the first two eigenvalues of the Schrodinger equation for the potential V(x) = Ax(4) + Bx(2) is achieved by using the Symanzik scaling symmetry. A kind of symmetry restoration when one of the potential parameters changes conveniently is observed. (C) 2000 Published by Elsevier B.V. B.V. All rights reserved.

Self-assembly of organometallic Pd(II) complexes via CH3 center dot center dot center dot pi interactions: the first example of a cyclopalladated compound with herringbone stacking pattern

Two binuclear cyclometallated compounds [Pd(C-2,N-dmba)(mu-N-3)](2) (1) and [Pd-2(C-2,N-dmba)(2)(mu-N-3)(mu-Cl)] (2) (dmba = N,N-dimethylbenzylarnine) have been synthesized and characterized by elemental 3 analysis, IR and NMR spectroscopies and single crystal X-ray diffraction crystallography. The ability of CH3 groups to form C(sp(3))-H...pi hydrogen bonds with phenyl rings is responsible for the molecular self-assembly within the crystals of 1 and 2. Compound 1 crystallizes as one-dimensional supramolecular chains whereas the crystal packing of 2 consists of a herringbone of sandwiches composed by two inversely related [Pd-2(C-2,N-dmba)(2)(mu-N-3)(mu-Cl)] molecules. (c) 2007 Elsevier B.V. All rights reserved.

STOCHASTIC QUANTIZATION AND 1/N EXPANSION

We study the 1/N expansion of field theories in the stochastic quantization method of Parisi and Wu using the supersymmetric functional approach. This formulation provides a systematic procedure to implement the 1/N expansion which resembles the ones used in the equilibrium. The 1/N perturbation theory for the nonlinear sigma-model in two dimensions is worked out as an example.