Cultivares de abacaxi.

O abacaxizeiro é uma fruteira amplamente cultivada no Brasil e representa excelente fonte de renda para diversas regiões do País. Estima-se que cerca de 70% da produção mundial de abacaxi provém da cultivar Smooth Cayenne. O predomínio do plantio desta cultivar, nos principais países produtores do mundo, vem proporcionando o desaparecimento de cultivares de interesse local ou regional. No Brasil e em outros países da América Latina, ocorrem diversas cultivares de abacaxi que estão sendo substituídas por Smooth Cayenne. Essas cultivares são importantes para o futuro da cultura e deveriam ser preservadas, caracterizadas e avaliadas. As cultivares de abacaxi mais conhecidas no mundo são classificadas em cinco grupos distintos (Cayenne, Spanish, Queen, Pernambuco ou Pérola e Mordilonus-Perolera), de acordo com um conjunto de caracteres comuns.bitstream/item/81508/1/cultivares-de-abacaxi-Rnato-Cabral-Circular-tecnica-33-1999.pdfMemória

Vacuum Polarization by a Magnetic Flux Tube at Finite Temperature in the Cosmic String Spacetime

In this paper we analyse the effect produced by the temperature in the vacuum polarization associated with charged massless scalar field in the presence of magnetic flux tube in the cosmic string spacetime. Three different configurations of magnetic fields are taken into account: $(i)$ a homogeneous field inside the tube, $(ii)$ a field proportional to $1/r$ and $(iii)$ a cylindrical shell with $\delta$-function. In these three cases, the axis of the infinitely long tube of radius $R$ coincides with the cosmic string. Because the complexity of this analysis in the region inside the tube, we consider the thermal effect in the region outside. In order to develop this analysis, we construct the thermal Green function associated with this system for the three above mentioned situations considering points in the region outside the tube. We explicitly calculate in the high-temperature limit, the thermal average of the field square and the energy-momentum tensor.Comment: 16 pages, 1 figur

Variedades de abacaxi.

Todas as variedades de abacaxi cujo interesse é o fruto, seja para consumo in natura ou para processamento, pertencem à espécie Ananas comosus var. comosus. Alguns clones de Ananas comosus var. erectifolius, Ananas comosus var. ananassoides e Ananas comosus var. bracteatus são cultivados para produção de fibra ou para fins ornamentais. Recentemente, houve grande incremento nestas formas de utilização. A variedade de abacaxi predominantemente cultivada no mundo é a Smooth Cayenne, responsável por cerca de 70% da produção mundial de abacaxi. Contudo, outras variedades como Singapore Spanish, Queen, Red Spanish, Pérola e Perolera são muito cultivadas e difundidas em nível mundial (Leal, 1990). No Brasil, onde a área de plantio em 2002 foi de 62.597 ha, com produção de 1.430.018 mil frutos e rendimento de 22.845 frutos/ha (IBGE, 2003), a variedade mais plantada é a Pérola, responsável por cerca de 80% da produção brasileira de abacaxi havaiano, cujos plantios se concentram no Sudeste do país, principalmente em São Paulo e na região do Triângulo Mineiro.bitstream/item/81569/1/Circular-Tecnica-63-Variedade-Abacaxi-Renato-Cabral-2003.pdfMemória

Monitoramento de plantios de abacaxi para manter as características da cultivar.

Todas as cultivares de abacaxi cujo interesse é o fruto, pertencem à espécie Ananas comosus var. comosus. Alguns clones de Ananas comosus var. erectifolius, Ananas comosus var. ananassoides e Ananas comosus var. bractetus são cultivados para produção de fibra ou para fins omamentais. Recentemente, houve grande incremento nestas formas de utilização.As principais características desejadas em uma cultivar de abacaxi são: crescimento rápido; folhas curtas, largas e com bordas sem espinhos; boa produção de mudas; fruto bem conformado, casca amarela; polpa amarela ou alaranjada, fime mas não fibrosa, teor de açúcar elevado, acidez moderada; coroa média a pequena. Associadas a estas características, procura-se ainda cultivares que produzam frutos de boa qualidade, que proporcionem altos rendimentos e que sejam resistentes e/ou tolerantes às principais pragas e doenças que ocorrem nos locais de plantio.bitstream/CNPMF/24012/1/abacaxi_38.pd

Quantitative constraints on modified gravity paradigms

We use low-redshift background cosmology data to place quantitative constraints on three separate modified gravity models, each of which aims to explain the low-redshift acceleration through a different physical mechanism. The Lifshitz cosmology is effectively a parametric extension of the canonical $\Lambda$CDM model, where a time-dependent cosmological constant originates from vacuum energy. The Infinite Statistics model is also a parametric extension of $\Lambda$CDM, where the dark energy is dynamic and originates from the curvature of a dual space-time. We show that the data restricts the additional parameters in these models to be consistent with their $\Lambda$CDM values, and in particular that it implies that the theoretically predicted value for a dimensionless coupling parameter in the Lifshitz model is ruled out at more than six standard deviations. In the Regge-Teitelboim model, gravity is described by embedding the usual space-time manifold in a fixed higher-dimensional background, and there is no parametric $\Lambda$CDM limit. We study several separate realizations of the model, respectively introduced by Davidson, by Fabi \textit{et al.}, and by Stern \& Xu, and show that the first two are ruled out by the low-redshift data we use, while the latter is consistent with this data but requires a non-standard value of the matter density. Overall, our analysis highlights the tight constraints imposed by current data on the allowed low-redshift deviations from the standard $\Lambda$CDM background evolution.Comment: 11 pages, 8 figures, Phys. Rev. D (in press

Vacuum Polarization for a Massless Spin-1/2 Field in the Global Monopole Spacetime at Nonzero Temperature

In this paper we present the effects produced by the temperature in the renormalized vacuum expectation value of the zero-zero component of the energy-momentum tensor associated with massless left-handed spinor field in the pointlike global monopole spacetime. In order to develop this calculation we had to obtain the Euclidean thermal Green function in this background. Because the expression obtained for the thermal energy density cannot be expressed in a closed form, its explicit dependence on the temperature is not completely evident. So, in order to obtain concrete information about its thermal behavior, we develop a numerical analysis of our result in the high-temperature limit for specific values of the parameter $\alpha$ which codify the presence of the monopole.Comment: 22 pages, LaTex format, 5 figure

Bipolar HII regions - Morphology and star formation in their vicinity - I - G319.88++00.79 and G010.32−-00.15

Our goal is to identify bipolar HII regions and to understand their morphology, their evolution, and the role they play in the formation of new generations of stars. We use the Spitzer and Herschel Hi-GAL surveys to identify bipolar HII regions. We search for their exciting star(s) and estimate their distances using near-IR data. Dense clumps are detected using Herschel-SPIRE data. MALT90 observations allow us to ascertain their association with the central HII region. We identify Class 0/I YSOs using their Spitzer and Herschel-PACS emissions. These methods will be applied to the entire sample of candidate bipolar HII regions. This paper focuses on two bipolar HII regions, one interesting in terms of its morphology, G319.88$+$00.79, and one in terms of its star formation, G010.32$-$00.15. Their exciting clusters are identified and their photometric distances estimated to be 2.6 kpc and 1.75 kpc, respectively. We suggest that these regions formed in dense and flat structures that contain filaments. They have a central ionized region and ionized lobes perpendicular to the parental cloud. The remains of the parental cloud appear as dense (more than 10^4 per cm^3) and cold (14-17 K) condensations. The dust in the PDR is warm (19-25 K). Dense massive clumps are present around the central ionized region. G010.32-00.14 is especially remarkable because five clumps of several hundred solar masses surround the central HII region; their peak column density is a few 10^23 per cm^2, and the mean density in their central regions reaches several 10^5 per cm^3. Four of them contain at least one massive YSO; these clumps also contain extended green objects and Class II methanol masers. This morphology suggests that the formation of a second generation of massive stars has been triggered by the central bipolar HII region. It occurs in the compressed material of the parental cloud.Comment: 32 pages, 28 figures, to be published in A&