172 research outputs found

    A taxonomic revision of the Neotropical termite genera Labiotermes Holmgren and Paracornitermes Emerson (Isoptera: Termitidae: Nasutitermitinae)

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    The taxonomy of the South American termite genus Labiotermes Holmgren (sensu novo) is revised,including identification keys to soldiers and workers, and distribution maps for all 10 species.Paracornitermes Emerson is treated as a new synonym of Labiotermes. Two new species aredescribed: L. guasu, from the Amazon rain forest and L. oreadicus, from the Cerrado of centralBrazil. Paracornitermes caapora Bandeira & Cancello and P. hirsutus Araujo are placed under thesynonymy of L. orthocephalus. The imagos of L. emersoni and L. orthocephalus are described forthe first time. The workers of all species are described and illustrated, including the enteric valve armature and the mixed segment. The soldiers of the species previously included inParacornitermes are redescribed.Fil: Constantino, Reginaldo. Universidade de Brasília; BrasilFil: Acioli, Agmo N. S.. PPG Entomologia; BrasilFil: Smith, Karen. Universidade de Brasília; BrasilFil: Cuezzo, Adriana Carolina. Fundación Miguel Lillo. Dirección de Zoología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Carvalho, Sergio H. C. Universidade de Brasília; BrasilFil: Vasconcellos, Alexandre. Universidade Federal do Rio Grande do Norte; Brasi

    Sequência completa do DNA-A de uma nova espécie de Begomovirus infectando tomateiro no Estado de Tocantins, Brasil.

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    O presente trabalho visou caracterizar uma nova espécie de Begomovirus detectada infectando tomateiro (Solanum lycopersicum L.) no Estado de Tocantins.Resumo 1381. Suplemento. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves

    Registro no Estado do Amazonas de um novo begomovírus do tomateiro relacionado com espécies virais da América Central e Caribe.

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    Esse trabalho visou caracterizar um isolado de Begomovirus encontrado infectando tomateiro no Estado do Amazonas. Plantas com sintomas de clorose interneral e amarelecimento apical foram coletadas na região produtora de tomate para consumo in natura em Silves-AM.Resumo 1382. Suplemento. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves

    Correlation energy of a two-dimensional electron gas from static and dynamic exchange-correlation kernels

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    We calculate the correlation energy of a two-dimensional homogeneous electron gas using several available approximations for the exchange-correlation kernel fxc(q,ω)f_{\rm xc}(q,\omega) entering the linear dielectric response of the system. As in the previous work of Lein {\it et al.} [Phys. Rev. B {\bf 67}, 13431 (2000)] on the three-dimensional electron gas, we give attention to the relative roles of the wave number and frequency dependence of the kernel and analyze the correlation energy in terms of contributions from the (q,iω)(q, i\omega) plane. We find that consistency of the kernel with the electron-pair distribution function is important and in this case the nonlocality of the kernel in time is of minor importance, as far as the correlation energy is concerned. We also show that, and explain why, the popular Adiabatic Local Density Approximation performs much better in the two-dimensional case than in the three-dimensional one.Comment: 9 Pages, 4 Figure

    Correlation energies of inhomogeneous many-electron systems

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    We generalize the uniform-gas correlation energy formalism of Singwi, Tosi, Land and Sjolander to the case of an arbitrary inhomogeneous many-particle system. For jellium slabs of finite thickness with a self-consistent LDA groundstate Kohn-Sham potential as input, our numerical results for the correlation energy agree well with diffusion Monte Carlo results. For a helium atom we also obtain a good correlation energy.Comment: 4 pages,1 figur
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