Loitering universe models in light of the CMB

Spatially flat loitering universe models have recently been shown to arise in the context of brane world scenarios. Such models allow more time for structure formation to take place at high redshifts, easing, e.g., the tension between the observed and predicted evolution of the quasar population with redshift. While having the desirable effect of boosting the growth of structures, we show that in such models the position of the first peak in the power spectrum of the cosmic microwave background anisotropies severely constrains the amount of loitering at high redshifts.Comment: 4 pages, 3 figures. Included discussion of the linear growth factor. Matches version accepted for publication in PR

IFMIF suitability for evaluation of fusion functional materials

The International FusionMaterials Irradiation Facility (IFMIF) is a future neutron source based on the D-Li stripping reaction, planned to test candidate fusionmaterials at relevant fusion irradiation conditions. During the design of IFMIF special attention was paid to the structural materials for the blanket and first wall, because they will be exposed to the most severe irradiation conditions in a fusion reactor. Also the irradiation of candidate materials for solid breeder blankets is planned in the IFMIF reference design. This paper focuses on the assessment of the suitability of IFMIF irradiation conditions for testing functionalmaterials to be used in liquid blankets and diagnostics systems, since they are been also considered within IFMIF objectives. The study has been based on the analysis and comparison of the main expected irradiation parameters in IFMIF and DEMO reactor

Production of annato (Bixa orellana L.) in an agroforestry system.

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Development and production of coconut palm (Cocos nucifera L.) in an agroforestry system.

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Production of peach palm (Bactris gasipaes) for palm heart in different polyculture systems.

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Production of cupuaçu (Theobroma grandiflorum) in different polyculture systems.

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Lower critical field H_c1 and barriers for vortex entry in Bi_2Sr_2CaCu_2O_{8+delta} crystals

The penetration field H_p of Bi_2Sr_2CaCu_2O_{8+delta} crystals is determined from magnetization curves for different field sweep rates dH/dt and temperatures. The obtained results are consistent with theoretical reports in the literature about vortex creep over surface and geometrical barriers. The frequently observed low-temperature upturn of H_p is shown to be related to metastable configurations due to barriers for vortex entry. Data of the true lower critical field H_c1 are presented. The low-temperature dependence of H_c1 is consistent with a superconducting state with nodes in the gap function. [PACS numbers: 74.25.Bt, 74.60.Ec, 74.60.Ge, 74.72.Hs

SUSY approach to Pauli Hamiltonians with an axial symmetry

A two-dimensional Pauli Hamiltonian describing the interaction of a neutral spin-1/2 particle with a magnetic field having axial and second order symmetries, is considered. After separation of variables, the one-dimensional matrix Hamiltonian is analyzed from the point of view of supersymmetric quantum mechanics. Attention is paid to the discrete symmetries of the Hamiltonian and also to the Hamiltonian hierarchies generated by intertwining operators. The spectrum is studied by means of the associated matrix shape-invariance. The relation between the intertwining operators and the second order symmetries is established and the full set of ladder operators that complete the dynamical algebra is constructed.Comment: 18 pages, 3 figure

Experiência em capacitação de técnicos da ATER em sistemas agroflorestais.

Neste trabalho são discutidas as metodologias e os resultados de oficinas de capacitação em sistemas agroflorestais oferecidas pela Embrapa Amazônia Ocidental a técnicos da Assistência Técnica e Extensão Rural (ATER) atuantes na capital e no interior do Estado do Amazonas

Amadurecimento de frutos de Plátano 'Terra Maranhão' tratados com 1-metilciclopropeno gasoso.

Os plátanos, genericamente conhecidos como banana-da-Terra, são tipos de banana com alto teor de amido e são consumidos ao natural ou, principalmente, mediante outras formas de processamento. Este trabalho objetivou avaliar o amadurecimento de frutos de plátano ?Terra Maranhão? tratados com 1-MCP gasoso. Os tratamentos consistiram de aplicação de 1-MCP gasoso a 25 °C, por 12 horas, a 0 (controle), 15 e 30 ppb. Os frutos foram avaliados a cada 5 dias durante 20 dias para as seguintes características: estádio de maturação; perda de massa (%); acidez titulável ? AT (% ácido málico); sólidos solúveis ? SS (%); e relação SS/AT. Foi utilizado o delineamento inteiramente casualizado, com quatro repetições de um buquê de três frutos cada. Os resultados deste estudo indicam que o 1-MCP foi capaz de retardar o amadurecimento dos frutos em pelo menos cinco dias. No entanto, as alterações envolvendo a polpa foram mais afetadas. Conclui-se que o 1-MCP possui alto potencial de retardar o amadurecimento de frutos de plátano ?Terra Maranhão?, mas são necessários novos estudos para ajustar o uso da tecnologia a este plátano