Disk and elliptical galaxies within renormalization group improved gravity

The paper is about possible effects of infrared quantum contributions to General Relativity on disk and elliptical galaxies. The Renormalization Group corrected General Relativity (RGGR model) is used to parametrize these quantum effects. The new RGGR results presented here concern the elliptical galaxy NGC 4374 and the dwarf disk galaxy DDO 47. Using the effective approach to Quantum Field Theory in curved background, one can argue that the proper RG energy scale, in the weak field limit, should be related to the Newtonian potential. In the context of galaxies, this led to a remarkably small variation of the gravitational coupling G, while also capable of generating galaxy rotation and dispersion curves of similar quality to the the best dark matter profiles (i.e., the profiles that have a core).Comment: 5 pages. This paper is based on a talk given by D.C. Rodrigues at the I CosmoSul meeting (Rio de Janeiro, RJ - Brazil. August, 01-05, 2011). To be published in AIP conference Proceeding

A utilização de Unidades Demonstrativas para a transferência de tecnologia.

A demonstração das tecnologias agrícolas é uma das formas de transferência adotadas pela Empresa Brasileira de Pesquisa Agropecuária ? Embrapa. Essa demonstração é feita para aproximar o agricultor dos benefícios gerados pela pesquisa. Nesse contexto, se insere o conceito de Unidade Demonstrativa (UD), mas o que vem a ser uma UD?bitstream/item/29508/1/adocao.pd

Modified gravity models and the central cusp of dark matter haloes in galaxies

The N-body dark matter (DM) simulations point that DM density profiles, e.g. the Navarro Frenk White (NFW) halo, should be cuspy in its centre, but observations disfavour this kind of DM profile. Here we consider whether the observed rotation curves close to the galactic centre can favour modified gravity models in comparison to the NFW halo, and how to quantify such difference. Two explicit modified gravity models are considered, Modified Newtonian Dynamics (MOND) and a more recent approach renormalization group effects in general relativity (RGGR). It is also the purpose of this work to significantly extend the sample on which RGGR has been tested in comparison to other approaches. By analysing 62 galaxies from five samples, we find that (i) there is a radius, given by half the disc scale length, below which RGGR and MOND can match the data about as well or better than NFW, albeit the formers have fewer free parameters; (ii) considering the complete rotation curve data, RGGR could achieve fits with better agreement than MOND, and almost as good as a NFW halo with two free parameters (NFW and RGGR have, respectively, two and one more free parameters than MOND)

On Galois-Division Multiple Access Systems: Figures of Merit and Performance Evaluation

A new approach to multiple access based on finite field transforms is investigated. These schemes, termed Galois-Division Multiple Access (GDMA), offer compact bandwidth requirements. A new digital transform, the Finite Field Hartley Transform (FFHT) requires to deal with fields of characteristic p, p \neq 2. A binary-to-p-ary (p \neq 2) mapping based on the opportunistic secondary channel is introduced. This allows the use of GDMA in conjunction with available digital systems. The performance of GDMA is also evaluated.Comment: 6 pages, 4 figures. In: XIX Simposio Brasileiro de Telecomunicacoes, 2001, Fortaleza, CE, Brazi

Ising Ferromagnet: Zero-Temperature Dynamic Evolution

The dynamic evolution at zero temperature of a uniform Ising ferromagnet on a square lattice is followed by Monte Carlo computer simulations. The system always eventually reaches a final, absorbing state, which sometimes coincides with a ground state (all spins parallel), and sometimes does not (parallel stripes of spins up and down). We initiate here the numerical study of ``Chaotic Time Dependence'' (CTD) by seeing how much information about the final state is predictable from the randomly generated quenched initial state. CTD was originally proposed to explain how nonequilibrium spin glasses could manifest equilibrium pure state structure, but in simpler systems such as homogeneous ferromagnets it is closely related to long-term predictability and our results suggest that CTD might indeed occur in the infinite volume limit.Comment: 14 pages, Latex with 8 EPS figure

Divergência genética em população pré-selecionada de bacuri (Platonia insignis).

Os frutos da Amazônia têm despertado grande interesse nos últimos anos, tanto em nível nacional quanto internacional em decorrência dos seus sabores exóticos, por apresentarem altos teores de vitaminas e antioxidantes e pelo aproveitamento de suas polpas no agronegócio e na indústria farmacêutica (FERNANDES et al., 2003; FRAZON, 2004). As demandas do mercado para a polpa do bacuri são semelhantes às do açaí e do cupuaçu, em que se verifica um evidente conflito entre a oferta natural e a crescente pressão da demanda dessas fruteiras devido sua sazonalidade (MENEZES et al., 2012). Os programas de melhoramento precisam se adequar e ser direcionados para atender as especificidades das diversas regiões e assim suprir as demandas de mercado e as restrições de produção (BATISTA, 2013). Em muitas situações, principalmente naquelas voltadas para fins de melhoramento genético, têm sido comum o estudo da diversidade genética com a finalidade de identificar genitores adequados ao cruzamento tendo em vista a obtenção de híbridos de maiores efeitos heteróticos que proporcionem maior segregação em recombinações e possibilitem o aparecimento de transgressivos (CRUZ et al., 2011). O bacuri apresenta flores perfeitas de tamanho grande, assim, a emasculação e os cruzamentos controlados se darão de maneira relativamente simples entre os genitores geneticamente divergentes, para a obtenção dos híbridos (progênies) do segundo ciclo de seleção recorrente. O objetivo deste trabalho foi determinar os grupos geneticamente divergentes entre genótipos de bacuri pré-selecionados para os atributos agrotecnológicos