Divergência genética entre acessos de batata-doce utilizando descritores morfoagronômicos das raízes.

Objetivou-se caracterizar morfoagronômicamente 23 genótipos de batata-doce do banco ativo de germoplasma mantido na Embrapa Hortaliças; utilizar estas características para avaliar a variabilidade genética entre os materiais pela aplicação dos métodos de Análise por agrupamento hierárquico e análise por componentes principais e estimar parâmetros populacionais

Desempenho de cultivares de batata-doce a partir mudas de alta qualidade fitossanitária em Ceilândia-DF.

O presente trabalho teve por objetivo avaliar o desempenho agronomico de oito cultivares utilizando mudas que passaram pela limpeza clonal. O experimento foi conduzido em condições de campo, no delineamento em blocos ao acaso com três repetições, em Ceilândia, DF.Suplemento. Edição dos Anais do 53 Congresso Brasileiro de Olericultura

Exocomet signatures around the A-shell star Φ\Phi Leo?

We present an intensive monitoring of high-resolution spectra of the Ca {\sc ii} K line in the A7IV shell star $\Phi$ Leo at very short (minutes, hours), short (night to night), and medium (weeks, months) timescales. The spectra show remarkable variable absorptions on timescales of hours, days, and months. The characteristics of these sporadic events are very similar to most that are observed toward the debris disk host star $\beta$ Pic, which are commonly interpreted as signs of the evaporation of solid, comet-like bodies grazing or falling onto the star. Therefore, our results suggest the presence of solid bodies around $\Phi$ Leo. To our knowledge, with the exception of $\beta$ Pic, our monitoring has the best time resolution at the mentioned timescales for a star with events attributed to exocomets. Assuming the cometary scenario and considering the timescales of our monitoring, our results indicate that $\Phi$ Leo presents the richest environment with comet-like events known to date, second only to $\beta$ Pic.Comment: A&A letters, proof-correcte

Electronic Band Structure In A Periodic Magnetic Field

We analyze the energy band structure of a two-dimensional electron gas in a periodic magnetic field of a longitudinal antiferromagnet by considering a simple exactly solvable model. Two types of states appear: with a finite and infinitesimal longitudinal mobility. Both types of states are present at a generic Fermi surface. The system exhibits a transition to an insulating regime with respect to the longitudinal current, if the electron density is sufficiently low.Comment: 8 pages, 5 figures; to appear in Phys. Rev. B '9

Desempenho de cultivares de batata-doce no Distrito federal.

O presente trabalho teve como objetivo avaliar o desempenho agronômico de seis cultivares e três variedades de batata-doce nas condições edafoclimáticas no Recanto das Emas, DF

Desempenho de hibridos de abóboras e morangas avaliadas no Distrito Federal.

O presente trabalho teve como objetivo avaliar o desempenho agronômico de oito hibridos experimentais de abóboras e morangas em Brasília, DF.Suplemento. Edição dos Anais do 53 Congresso Brasileiro de Olericultura, jul. 2014

Hofstadter-type energy spectra in lateral superlattices defined by periodic magnetic and electrostatic fields

We calculate the energy spectrum of an electron moving in a two-dimensional lattice which is defined by an electric potential and an applied perpendicular magnetic field modulated by a periodic surface magnetization. The spatial direction of this magnetization introduces complex phases into the Fourier coefficients of the magnetic field. We investigate the effect of the relative phases between electric and magnetic modulation on band width and internal structure of the Landau levels.Comment: 5 LaTeX pages with one gif figure to appear in Phys. Rev.

Non equilibrium effects in fragmentation

We study, using molecular dynamics techniques, how boundary conditions affect the process of fragmentation of finite, highly excited, Lennard-Jones systems. We analyze the behavior of the caloric curves (CC), the associated thermal response functions (TRF) and cluster mass distributions for constrained and unconstrained hot drops. It is shown that the resulting CC's for the constrained case differ from the one in the unconstrained case, mainly in the presence of a ``vapor branch''. This branch is absent in the free expanding case even at high energies . This effect is traced to the role played by the collective expansion motion. On the other hand, we found that the recently proposed characteristic features of a first order phase transition taking place in a finite isolated system, i.e. abnormally large kinetic energy fluctuations and a negative branch in the TRF, are present for the constrained (dilute) as well the unconstrained case. The microscopic origin of this behavior is also analyzed.Comment: 21 pages, 11 figure