2,651 research outputs found

    Diversidade de fungos micorrízicos arbusculares em áreas revegetadas após a mineração de bauxita.

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    A contribuição da diversidade dos FMAs para manutenção da diversidade e funcionalidade de ecossistemas naturais tem sido pouco estudada. Neste trabalho objetivou-se avaliar a diversidade de FMAs em áreas revegetadas em diferentes momentos. Com base na morfologia de esporos 13 espécies distintas foram encontradas, com predomínio de espécies dos gêneros Glomus e Acaulospora. Glomus macrocarpum foi a espécies mais freqüente e abundante e as parcelas das áreas revegetadas nos anos de 1985A1, 1998A1, 2002-1, 2002A1, 2004FP e 2006-1 apresentaram os maiores valores do índice de diversidade Shannon. Não foi observada relação entre o tempo de revegtação e a diversidade de FMAs

    Sobrevivência e crescimento de leguminosas arbóreas em no Estado do Amapá.

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    Neste trabalho objetivou-se avaliar a sobrevivência e o crescimento das leguminosas arbóreas Tachigali paniculata e Inga edulis em áreas de capoeira no Estado do Amapá. O plantio foi realizado em 2012 e as mudas foram avaliadas aos 61, 140, 203, 275, 385, 445 e 524 dias após transplante. Observou-se maior sobrevivência e incremento em altura das mudas de I. edulis no município de Tartarugalzinho. Não observou-se diferença na sobrevivência e incremento em altura para as mudas de T. paniculata entre os municípios de Porto Grande e Itaubal

    Calagem e adubação em feijão-caupi no Amapá: Tumucumaque - Ano 1.

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    O feijão-caupi é uma fonte alimentar de extrema importância em regiões tropicais e subtropicais do mundo. Neste estudo objetivou-se avaliar diferentes doses de calcário, P e K para a cultivar de feijão-caupi Tumucumaque. Dois experimentos foram conduzidos em condição de campo, sendo um avaliando 6 doses de calcário e um avaliando 4 doses de P e 4 doses de K. Não houve efeito significativo das diferentes doses de calcário e K sobre o número grãos; massa de grãos e produtividade do feijão-caupi. A cultivar de feijão-caupi Tumucumaque apresenta resposta à aplicação de doses de P em relação à produtividade de grãos

    Open and hidden charm in proton-nucleus and heavy-ion collisions

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    We review the collectivity and the suppression pattern of charmed mesons - produced in proton-nucleus and nucleus-nucleus collisions at SPS (158 AGeV) and RHIC energies (21 ATeV) - in comparison to dynamical and thermal models. In particular, we examine the charmonium `melting' and the `comover dissociation' scenarios - implemented in a microscopic transport approach - in comparison to the available data from the SPS and RHIC. The analysis shows that the dynamics of c, c-bar quarks at RHIC are dominated by partonic or `pre-hadronic' interactions in the strongly coupled plasma stage. Both the `charmonium melting' and the hadronic `comover absorption and recreation model' are found, however, to be compatible with the experimental observation at SPS energies; the experimental ratio of Psi'/J/Psi versus centrality clearly favors the `hadronic comover' scenario. We find that the collective flow of charm in the purely hadronic Hadron-String Dynamics (HSD) transport appears compatible with the data at SPS energies, but substantially underestimates the data at top RHIC energies. Thus, the large elliptic flow v2 of D-mesons and the low R_AA(p_T) of J/Psi seen experimentally have to be attributed to early interactions of non-hadronic degrees of freedom. Simultaneously, we observe that non-hadronic interactions are mandatory in order to describe the narrowing of the J/Psi rapidity distribution from pp to central Au+Au collisions at the top RHIC energy. We demonstrate additionally that the strong quenching of low-pT J/Psi's in central Au+Au collisions indicates that a large fraction of final J/Psi mesons is created by a coalescence mechanism close to the phase boundary. Throughout this review we, furthermore, provide predictions for charm observables from Au+Au collisions at FAIR energies of 25-35 AGeV.Comment: review for Int. J. Mod. Phys. E, 75 pages, 50 figure

    Valor nutritivo de componentes da planta e dos co-produtos do desfibramento do sisal.

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    Objetivou-se avaliar a composição bromatológica e a digestibilidade in vitro da matéria seca dos componentes da planta: cepa e rebentos, e dos co-produtos do desfibramento do sisal: mucilagem (in natura e feno) e pó de batedeira

    A Memetic Analysis of a Phrase by Beethoven: Calvinian Perspectives on Similarity and Lexicon-Abstraction

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    This article discusses some general issues arising from the study of similarity in music, both human-conducted and computer-aided, and then progresses to a consideration of similarity relationships between patterns in a phrase by Beethoven, from the first movement of the Piano Sonata in A flat major op. 110 (1821), and various potential memetic precursors. This analysis is followed by a consideration of how the kinds of similarity identified in the Beethoven phrase might be understood in psychological/conceptual and then neurobiological terms, the latter by means of William Calvin’s Hexagonal Cloning Theory. This theory offers a mechanism for the operation of David Cope’s concept of the lexicon, conceived here as a museme allele-class. I conclude by attempting to correlate and map the various spaces within which memetic replication occurs

    Arbuscular mycorrhizal fungi diversity in revegetated areas after bauxite mining.

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    Arbuscular mycorrhizal fungi (AMF) are obligatory biotrophs that have a symbiotic evolutionary relationship with about 80% of all terrestrial plant species. The fungus mainly supplies water and nutrients to the plant and receives photoassimilates. The AMF diversity affects both the competition among species and floristic composition of an area. Fluctuations in the population of this group of microorganisms can cause fluctuations in plant populations above ground. In this work, the AMF community profile in areas with different ages of revegetation was evaluated by morphological identification of spores and denaturing gradient gel electrophoresis (DGGE) techniques. We found 12 AMF species and dominance of the species Glomus macrocarpum determined by spore density. Since the richness level observed in each plot was low and there was predominance of one species of AMF, it can be concluded that these areas still present a high degree of disturbance. It was possible to detect complex band profiles by DGGE analyses for the two plant species studied, Visnia latifolia and Cecropia hololeuca. No relationship between AMF diversity and revegetation time was observed in these areas
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