A Compound model for the origin of Earth's water

One of the most important subjects of debate in the formation of the solar system is the origin of Earth's water. Comets have long been considered as the most likely source of the delivery of water to Earth. However, elemental and isotopic arguments suggest a very small contribution from these objects. Other sources have also been proposed, among which, local adsorption of water vapor onto dust grains in the primordial nebula and delivery through planetesimals and planetary embryos have become more prominent. However, no sole source of water provides a satisfactory explanation for Earth's water as a whole. In view of that, using numerical simulations, we have developed a compound model incorporating both the principal endogenous and exogenous theories, and investigating their implications for terrestrial planet formation and water-delivery. Comets are also considered in the final analysis, as it is likely that at least some of Earth's water has cometary origin. We analyze our results comparing two different water distribution models, and complement our study using D/H ratio, finding possible relative contributions from each source, focusing on planets formed in the habitable zone. We find that the compound model play an important role by showing more advantage in the amount and time of water-delivery in Earth-like planets.Comment: Accepted for publication in The Astrophysical Journa

H\"older mean applied to Anderson localization

The phase diagram of correlated, disordered electron systems is calculated within dynamical mean-field theory using the H\"older mean local density of states. A critical disorder strength is determined in the Anderson-Falicov-Kimball model and the arithmetically and the geometrically averages are found to be just particular means used respectively to detect or not the Anderson localization. Correlated metal, Mott insulator and Anderson insulator phases, as well as coexistence and crossover regimes are analyzed in this new perspective.Comment: 6 pages, 6 figures: Phys. Rev. B 76, 035111 (2007

Vassoura-de-bruxa do cupuaçuzeiro na Amazônia.

Banco Ativo de germoplasma (BAG). Desenvolvimento de cultivares resistente. Avaliação da vassoura-de-bruxa em cupuaçuzeiro em condições de campo com uso de escala diagramática. Metodologia para inoculação de M. perniciosa em cupuaçuzeiro. Seleção de variáveis na avaliação de genótipos de cupuaçuzeiro. Controle cultural. Controle químico. Controle biológico e alternativo

Severidade da antracnose do sorgo em misturas de cultivares.

xEdição dos Resumos do XLI Congresso Brasileiro de Fitopatologia, Belo Horizonte, MG, ago. 2008

Interação insetos-sementes: o mutualismo é possível.

Nesta publicação encontram-se reunidas informações sobre insetos e sementes de Parkia multijuga, Coffea canephora e Gossypium thurberi, para produzir um quadro comparativo da interação entre esses grupos de espécies. Argumentou-se que, no período reprodutivo das plantas, a cooperação entre estes organismos pode ir além da polinização. Foi proposto que os insetos podem ser elementos chave na estratégia reprodutiva das plantas, contribuindo decisivamente para o sucesso da germinação e estabelecimento de novas plântulas.bitstream/item/24657/1/doc98-insetos-sementes.pd

Position-dependent-mass; Cylindrical coordinates, separability, exact solvability, and PT-symmetry

The kinetic energy operator with position-dependent-mass in cylindrical coordinates is obtained. The separability of the corresponding Schr\"odinger equation is discussed within radial cylindrical mass settings. Azimuthal symmetry is assumed and spectral signatures of various z-dependent interaction potentials (Hermitian and non-Hermitian PT-symmetric) are reported.Comment: 16 page