Otimização de protocolo para o enraizamento in vitro de jalapa (Mandevilla illustris) (Vell.) R. E. Woodson.

Suplemento. Edição dos Trabalhos do 49 Congresso Brasileiro de Olericultura, Águas de Lindóia, ago. 2009

Diversidade genética em populações naturais de infalível.

Suplemento. Edição dos Trabalhos do 49 Congresso Brasileiro de Olericultura, Águas de Lindóia, ago. 2009

Ocorrência de fungos micorrízicos em catuaba (Anemopaegma arvense (Vell.) Stell. ex de Souza - Bignoniaceae), uma planta medicinal do Cerrado em risco de extinção.

Este trabalho foi realizado com o objetivo de verificar a ocorrência de fungos micorrízicos, identificar suas espécies, e avaliar a colonização em raízes de plantas de diferentes populações e variedades de Anemopaegma arvense, uma planta medicinal do Cerrado em risco de extinção. As avaliações da colonização micorrízica e identificação de espécies de fungos micorrízicos arbusculares (FMAs) foram realizadas no Laboratório de Microbiologia do Solo da Universidade Federal de Lavras (UFLA). Foram utilizadas raízes de 10 plantas coletadas em diferentes locais juntamente com as amostras de solo próximo ao sistema radicular de populações naturais das variedades: glabra, puberula e petiolata. Os esporos foram extraídos do solo por meio da metodologia de peneiramento úmido e, para a avaliação e observação da colonização radicular, as raízes coradas foram observadas em microscópio estereoscópico (ampliação 10 a 40x). Em todas as amostras analisadas foi possível identificar espécies de FMAs, exceto para a variedade puberula, coletada no município de Mogi Guaçu-SP. O número de esporos variou de maneira significativa entre as amostras e os locais amostrados, não havendo distribuição regular. Acaulospora scrubiculata, A. spinosa, A. longula, Escustelospora heterogama, Paraglomus occultum, Gigaspora margarita, Gigaspora sp., dentre outros, encontram-se entre as espécies identificadas. Quanto à avaliação da colonização micorrízica nas raízes, observou-se que todas as variedades foram colonizadas no sitema radicular, verificada por meio da presença de hifas. No entanto, a colonização não foi constatada em todas as amostras avaliadas e também não foi observada a formação de arbúsculos e/ou vesículas.Suplemento 1

Micorrizas arbusculares em populações naturais de catuaba (Anemopaegma arvense (Vell.) Stell. ex de Souza).

O objetivo deste trabalho foi verificar a ocorrência, identificar espécies de fungosmicorrízicos (MAs) e avaliar a colonização em raízes de plantas de diferentes populações evariedades deAnemopaegma arvense(Vell.) Stell. ex de Souza

Enraizamento in vitro de catuaba (Anemopaegma arvense ) (Vell.) Stell. ex de Souza.

Este trabalho teve como objetivo avaliar os efeitos de diferentes concentrações e tipos de poliaminas e diferentes concentrações de dithiothreitol (DTT) no enraizamento in vitro de A. Arvense

Electron cotunneling through doubly occupied quantum dots: effect of spin configuration

A microscopic theory is presented for electron cotunneling through doubly occupied quantum dots in the Coulomb blockade regime. Beyond the semiclassic framework of phenomenological models, a fully quantum mechanical solution for cotunneling of electrons through a one-dimensional quantum dot is obtained using a quantum transmitting boundary method without any fitting parameters. It is revealed that the cotunneling conductance exhibits strong dependence on the spin configuration of the electrons confined inside the dot. Especially for the triplet configuration, the conductance shows an obvious deviation from the well-known quadratic dependence on the applied bias voltage. Furthermore, it is found that the cotunneling conductance reveals more sensitive dependence on the barrier width than the height

Mesoscopic effects in tunneling between parallel quantum wires

We consider a phase-coherent system of two parallel quantum wires that are coupled via a tunneling barrier of finite length. The usual perturbative treatment of tunneling fails in this case, even in the diffusive limit, once the length L of the coupling region exceeds a characteristic length scale L_t set by tunneling. Exact solution of the scattering problem posed by the extended tunneling barrier allows us to compute tunneling conductances as a function of applied voltage and magnetic field. We take into account charging effects in the quantum wires due to applied voltages and find that these are important for 1D-to-1D tunneling transport.Comment: 8 pages, 7 figures, improved Figs., added Refs. and appendix, to appear in Phys. Rev.

Oxidation resistance of graphene-coated Cu and Cu/Ni alloy

The ability to protect refined metals from reactive environments is vital to many industrial and academic applications. Current solutions, however, typically introduce several negative effects, including increased thickness and changes in the metal physical properties. In this paper, we demonstrate for the first time the ability of graphene films grown by chemical vapor deposition to protect the surface of the metallic growth substrates of Cu and Cu/Ni alloy from air oxidation. SEM, Raman spectroscopy, and XPS studies show that the metal surface is well protected from oxidation even after heating at 200 \degree C in air for up to 4 hours. Our work further shows that graphene provides effective resistance against hydrogen peroxide. This protection method offers significant advantages and can be used on any metal that catalyzes graphene growth

Phonons and related properties of extended systems from density-functional perturbation theory

This article reviews the current status of lattice-dynamical calculations in crystals, using density-functional perturbation theory, with emphasis on the plane-wave pseudo-potential method. Several specialized topics are treated, including the implementation for metals, the calculation of the response to macroscopic electric fields and their relevance to long wave-length vibrations in polar materials, the response to strain deformations, and higher-order responses. The success of this methodology is demonstrated with a number of applications existing in the literature.Comment: 52 pages, 14 figures, submitted to Review of Modern Physic

MICE: the Muon Ionization Cooling Experiment. Step I: First Measurement of Emittance with Particle Physics Detectors

The Muon Ionization Cooling Experiment (MICE) is a strategic R&D project intended to demonstrate the only practical solution to providing high brilliance beams necessary for a neutrino factory or muon collider. MICE is under development at the Rutherford Appleton Laboratory (RAL) in the United Kingdom. It comprises a dedicated beamline to generate a range of input muon emittances and momenta, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. The emittance of the incoming beam will be measured in the upstream magnetic spectrometer with a scintillating fiber tracker. A cooling cell will then follow, alternating energy loss in Liquid Hydrogen (LH2) absorbers to RF cavity acceleration. A second spectrometer, identical to the first, and a second muon identification system will measure the outgoing emittance. In the 2010 run at RAL the muon beamline and most detectors were fully commissioned and a first measurement of the emittance of the muon beam with particle physics (time-of-flight) detectors was performed. The analysis of these data was recently completed and is discussed in this paper. Future steps for MICE, where beam emittance and emittance reduction (cooling) are to be measured with greater accuracy, are also presented