Water quality assessment of Portuguese streams: Regional or national predictive models?

http://www.sciencedirect.com/science/article/B6W87-4TY8WB4-2/2/5bab94f8490387f7a8da832e49003d6

Critical fluctuations and random-anisotropy glass transition in nematic elastomers

We carry out a detailed deuterium NMR study of local nematic ordering in polydomain nematic elastomers. This system has a close analogy to the random-anisotropy spin glass. We find that, in spite of the quadrupolar nematic symmetry in 3-dimensions requiring a first-order transition, the order parameter in the quenched ``nematic glass'' emerges via a continuous phase transition. In addition, by a careful analysis of the NMR line shape, we deduce that the local director fluctuations grow in a critical manner around the transition point. This could be the experimental evidence for the Aizenman-Wehr theorem about the quenched impurities changing the order of discontinuous transition

Molecular mobility, composition and structure analysis in glycerol plasticised chitosan films

This study was developed with the purpose to investigate the effect of polysaccharide/plasticiser concentration on the microstructure and molecular dynamics of polymeric film systems, using transmission electron microscope imaging (TEM) and nuclear magnetic resonance (NMR) techniques. Experiments were carried out in chitosan/glycerol films prepared with solutions of different composition. The films obtained after drying and equilibration were characterised in terms of composition, thickness and water activity. Results show that glycerol quantities used in film forming solutions were responsible for films composition; while polymer/total plasticiser ratio in the solution determined the thickness (and thus structure) of the films. These results were confirmed by TEM. \NMR\ allowed understanding the films molecular rearrangement. Two different behaviours for the two components analysed, water and glycerol were observed: the first is predominantly moving free in the matrix, while glycerol is mainly bounded to the chitosan chain.Authors Joana F. Fundo and Mafalda A.C. Quintas acknowledge Fundacao para a Ciencia e a Tecnologia (grants SFRH/BD/62176/2009 and SFRH/BPD/41715/2007, respectively), and Portuguese NMR Network

Distribution pattern of anurans from three mountain complexes in southeastern Brazil and their conservation implications

Biogeographic tools support spatial distribution pattern hypotheses and help to determine priority areas for conservation. Our aim was to verify biogeographic patterns for anurans in three mountain complexes in southeastern Brazil, as well as to discuss the status of species conservation recorded and the biogeographical units evaluated. We selected 16 areas distributed in the Serra da Mantiqueira complex, south of Serra do Espinhaço and Serra da Canastra. We used the occurrence (geographic coordinates) of each species in the localities to determine areas of endemism applying the Endemicity Analysis method. We also tested whether similarity between areas was explained by geographic distance (Multiple Regression on distance Matrices-MRM). The Serra do Itatiaia, Serra da Canastra, Plateau of Poços de Caldas and Serra do Cipó were the areas that presented the highest number of species restricted to them. Through the Endemicity Analysis, we identified four areas of endemism with higher scores. The MRM revealed that the geographic distance explained 41% of species dissimilarity between areas. Most of the endemic species from these areas have inaccurate conservation statuses (data deficient or unevaluated). These results highlight the need for greater research efforts towards understanding species restricted by distribution, as well as the priority in conserving these endemic areas

A percepção dos moradores de Parintins - Am, sobre arborização urbana.

Com objetivo de avaliar o que pensam os moradores de Parintins a respeito da arborização urbana, vantagens e desvantagens, as espécies e suas preferências e formas de apoio, colaboração e manutenção a arborização da cidade. Espera-se que este estudo possa contribuir para a elaboração de um plano de arborização da cidade de Parintins

Orbital glass and spin glass states of 3He-A in aerogel

Glass states of superfluid A-like phase of 3He in aerogel induced by random orientations of aerogel strands are investigated theoretically and experimentally. In anisotropic aerogel with stretching deformation two glass phases are observed. Both phases represent the anisotropic glass of the orbital ferromagnetic vector l -- the orbital glass (OG). The phases differ by the spin structure: the spin nematic vector d can be either in the ordered spin nematic (SN) state or in the disordered spin-glass (SG) state. The first phase (OG-SN) is formed under conventional cooling from normal 3He. The second phase (OG-SG) is metastable, being obtained by cooling through the superfluid transition temperature, when large enough resonant continuous radio-frequency excitation are applied. NMR signature of different phases allows us to measure the parameter of the global anisotropy of the orbital glass induced by deformation.Comment: 7 pages, 6 figures, Submitted to Pis'ma v ZhETF (JETP Letters

Levantamento das práticas agroecológicas da comunidade periurbana do Puraquequara Manaus/AM.

A Agroecologia é um enfoque científico que oferece os princípios e as metodologias para apoiar a transição do atual modelo de desenvolvimento rural e de agricultura convencionais para estilos de desenvolvimento rural e de agricultura sustentáveis, buscando, num horizonte temporal, a construção de novos saberes socioambientais que alimentem um processo de transição agroecológica