Building analytical three-field cosmological models

A difficult task to deal with is the analytical treatment of models composed by three real scalar fields, once their equations of motion are in general coupled and hard to be integrated. In order to overcome this problem we introduce a methodology to construct three-field models based on the so-called "extension method". The fundamental idea of the procedure is to combine three one-field systems in a non-trivial way, to construct an effective three scalar field model. An interesting scenario where the method can be implemented is within inflationary models, where the Einstein-Hilbert Lagrangian is coupled with the scalar field Lagrangian. We exemplify how a new model constructed from our method can lead to non-trivial behaviors for cosmological parameters.Comment: 11 pages, and 3 figures, updated version published in EPJ

Cosmological scenarios from multiquintessence

In this work we derive and analyse cosmological scenarios coming from multi-component scalar field models. We consider a direct sum of a sine-Gordon with a Z2 model, and also a combination of those with a BNRT model. Moreover, we work with a modified version of the BNRT model, which breaks the Z2 x Z2 symmetry of the original BNRT potential, coupled with the sine-Gordon and with the standard Z2 models. We show that our approach can be straightforwardly elevated to $N$ fields. All the computations are made analytically and some parameters restriction is put forward in order to get in touch with complete and realistic cosmological scenarios

Avaliação de extratores de boro em solo cultivado com alfafa.

Apesar do limite de deficiência e toxidez do B ser na maioria das culturas estreita, na alfafa a faixa utilizada para determinar o nível crítico é ampla, variando de 20 a 80 mg de B kg-1, porém, esses valores foram estabelecidos em condições de clima temperado e com cultivares diferentes da utilizada no Brasil. O objetivo deste trabalho foi verificar a eficiência de extratores [B (Mehlich 1, Mehlich 3, água quente, KCl 1,0 mol L-1, Manitol 0,05 mol L-1 + CaCl2 0,01 mol L-1, Ca(H2PO4)2.H2O 0,01 mol L-1, HCl 0,05 mol L-1] na determinação da disponibilidade do B do solo. Os resultados mostraram que para obtenção das maiores produções de MSPA, os teores de B disponível solo nas seis épocas de amostragem, variam de 0,21 a 0,49 mg kg-1 => B-H2Oq; 0,59 a 1,19 mg kg-1 => B-KCl; 1,74 a 3,45 mg kg-1 => B-M1; 1,81 a 2,54 mg kg-1 => B-M3; 0,47 a 0,84 mg kg-1 => B-CaPO4; 0,33 a 0,71 mg kg-1 => B-CaCl2; 0,67 a 1,06 mg kg-1 => B-HCl; Os extratores B-M1 e B-M3 apresentam maior capacidade de recuperação do B disponível no solo do que B-H2Oq, B-CaPO4, B-CaCl2 e B-KCl e B-HCl;Fertbio

Resonant Orbital Dynamics in LEO Region: Space Debris in Focus

The increasing number of objects orbiting the earth justifies the great attention and interest in the observation, spacecraft protection, and collision avoidance. These studies involve different disturbances and resonances in the orbital motions of these objects distributed by the distinct altitudes. in this work, objects in resonant orbital motions are studied in low earth orbits. Using the two-line elements (TLE) of the NORAD, resonant angles and resonant periods associated with real motions are described, providing more accurate information to develop an analytical model that describes a certain resonance. the time behaviors of the semimajor axis, eccentricity, and inclination of some space debris are studied. Possible irregular motions are observed by the frequency analysis and by the presence of different resonant angles describing the orbital dynamics of these objects.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo UNIFESP, BR-12231280 Sao Jose Dos Campos, SP, BrazilAstron Observ, AMU, PL-60286 Poznan, PolandITA, BR-12228900 Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo UNIFESP, BR-12231280 Sao Jose Dos Campos, SP, BrazilFAPESP: 2012/24369-0FAPESP: 2012/21023-6CNPq: 303070/2011-0Web of Scienc

Morphology, biology and pesticide tolerance of Chelotogenes ornatus (Acai: Cheyletidae).

This paper reports on the morphology, biology and pesticide tolerance of Cheletogenes ornatus, the most common predator of Pinnaspis aspidistrae in the region of Juazeiro- Bahia- Brazil. Some differences between C. ornatus from Brazil and redescriptions in the literature are mentioned in this paper. At 28 +ou- 5oC the duration of the life cycle was 40.6 and 31 days for female gametes and male gametes respectively. Females had 2 nymphal stages while the only male obtained in the laboratory had a single nymphal stage. C. ornatus reproduced by thelytokous parthenogenesis, and male gametes were seldom produced. The peak was ca. 0.8 crawler of P. aspidistrae/gemale gamete/day. The least harmful chemicals to adult females of C. ornatus were methyl parathion, malathion, cyhexatin, zineb and sulfur. Those chemicals caused less than 10% mortality of female gametes at he recommended rates on citrus. COncurrently, the first 2 chemicals caused over 70% mortality of crawlers of P. aspidistrae in the laboratory at the recommended rates

Acompanhamento da umidade de um solo coberto pela vegetação de cerrado usando a técnica de TDR (Rflectometria no Domínio do Tempo).

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