Teste de fungicidas em viveiros para controle do "mal das folhas" da seringueira.

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Thermostatistics of overdamped motion of interacting particles

We show through a nonlinear Fokker-Planck formalism, and confirm by molecular dynamics simulations, that the overdamped motion of interacting particles at T=0, where T is the temperature of a thermal bath connected to the system, can be directly associated with Tsallis thermostatistics. For sufficiently high values of T, the distribution of particles becomes Gaussian, so that the classical Boltzmann-Gibbs behavior is recovered. For intermediate temperatures of the thermal bath, the system displays a mixed behavior that follows a novel type of thermostatistics, where the entropy is given by a linear combination of Tsallis and Boltzmann-Gibbs entropies.Comment: 4 pages, 2 figure

Análise de viabilidade econômica de um sistema de produção modal de eucalipto para lenha na região de Itapeva, SP.

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The mosaic of habitats in the high-altitude Brazilian rupestrian fields is a hotspot for arbuscular mycorrhizal fungi.

The high diversity in rupestrian field vegetation has been attributed to the mosaic of environments formed by several soil classes, rugged relief and microclimatic variation. Although advances in the knowledge of some biological areas in rupestrian fields have been made, little is known about the relevance of soil microorganisms and their relationships with the vegetation. Symbiosis with arbuscular mycorrhizal fungi (AMF) is one of the most studied interactions between microorganisms and plants, because they are ubiquitous and contribute to the sustainability of ecosystems. This study aimed to investigate the occurrence and diversity of AMF species and to evaluate their relationship with soil physicochemical attributes and plant diversity in different habitats of the rupestrian fields from the Cadeia do Espinhaço, Serra do Cipó, Brazil. These rupestrian fields were delimited into five distinct habitats: rock outcrop, quartz gravel fields, sandy bogs, peat bogs and the Cerrado. Forty-nine AMF species were identified as belonging to nine families and twelve genera. Among them, Acaulospora colossica and Pacispora dominikii were found for the first time in Brazil. The results of this study suggest that the diversity of AMF is related to the heterogeneity of habitats and that the soil texture (coarse sand, gravel and silt) is better related to the structure of these fungi communities than to the soil chemical attributes. Plant species richness was related to AMF richness only in the quartz gravel field, rocky outcrop, and sandy bog habitats. Considering these habitats constitute one of the most menaced ecosystems on the planet, our survey provides information to improve knowledge about rupestrian field biodiversity, thus supporting policy actions for its conservation and preservation

Desenvolvimento de metodologia de criação e multiplicação de Aphis gossypii: avanços e sucessos.

Estudos sobre as mais diversas formas de controle de pragas e utilização de inimigos naturais, exigem artrópodes em quantidade e qualidade

Substituição do farelo de soja por uréia na suplementação de vacas leiteiras no sertão pernambucano.

A pesquisa objetivou avaliar o efeito da substituição do farelo de soja pelo nitrogênio não protéico (NNP), na forma de uréia e sulfato de amônia, na suplementação de vacas leiteiras alimentadas com capim bufffel diferido e palma forrageira. O trabalho foi realizado na Estação Experimental do IPA em Serra Talhada ?PE. Em uma área de 7,5 ha de pasto de buffel foram alimentadas 8 vacas, quatro da raça guzerá e quatro da girolando, suplementadas com 38 kg de palma forrageira (P) mais farelo de soja (FS) sendo substituído por uréia + sulfato de amônia (U+SA). Utilizou-se um delineamento em quadrado latino, e os tratamentos foram constituídos P + FS (1,69 kg FS); P + 2/3FS + 1/3U (1,13 kg FS + 97 g U+SA); P + 1/3FS + 2/3U (0,56 kg FS + 195 g U+SA) e P+U (292 g U). As vacas da raça girolando mostraram-se mais produtivas que as da raça guzerá com uma produção de 7,08 e 7,31 contra 4,67 e 5,34 kg/dia, respectivamente, para leite e leite corrigido para 4% de gordura. Não houve diferença entre os tratamentos, nem interação raça x tratamentos, concluindo-se que o NNP substituir o farelo de soja nas condições em que se realizou o experiment

The role of dynamical polarization of the ligand to metal charge transfer excitations in {\em ab initio} determination of effective exchange parameters

The role of the bridging ligand on the effective Heisenberg coupling parameters is analyzed in detail. This analysis strongly suggests that the ligand-to-metal charge transfer excitations are responsible for a large part of the final value of the magnetic coupling constant. This permits to suggest a new variant of the Difference Dedicated Configuration Interaction (DDCI) method, presently one of the most accurate and reliable for the evaluation of magnetic effective interactions. This new method treats the bridging ligand orbitals mediating the interaction at the same level than the magnetic orbitals and preserves the high quality of the DDCI results while being much less computationally demanding. The numerical accuracy of the new approach is illustrated on various systems with one or two magnetic electrons per magnetic center. The fact that accurate results can be obtained using a rather reduced configuration interaction space opens the possibility to study more complex systems with many magnetic centers and/or many electrons per center.Comment: 7 pages, 4 figure