511 research outputs found
The Hamilton-Jacobi Approach to Teleparallelism
We intend to analyse the constraint structure of Teleparallelism employing
the Hamilton-Jacobi formalism for singular systems. This study is conducted
without using an ADM 3+1 decomposition and without fixing time gauge condition.
It can be verified that the field equations constitute an integrable system.Comment: 12 pages, no figur
Perfil tecnico-economico dos perimetros irrigados das bacias do Curu e Baixo Acarau
bitstream/CNPAT/7902/1/doc80.pd
34. Grip strength across Europe –North/ South and East/West divides
info:eu-repo/semantics/publishedVersio
Quantum Cosmology in Scalar-Tensor Theories With Non Minimal Coupling
Quantization in the minisuperspace of non minimal scalar-tensor theories
leads to a partial differential equation which is non separable. Through a
conformal transformation we can recast the Wheeler-DeWitt equation in an
integrable form, which corresponds to the minimal coupling case, whose general
solution is known. Performing the inverse conformal transformation in the
solution so found, we can construct the corresponding one in the original
frame. This procedure can also be employed with the bohmian trajectories. In
this way, we can study the classical limit of some solutions of this quantum
model. While the classical limit of these solutions occurs for small scale
factors in the Einstein's frame, it happens for small values of the scalar
field non minimally coupled to gravity in the Jordan's frame, which includes
large scale factors.Comment: latex, 18 page
Avaliação do valor nutritivo do bagaço de cana-de-açúcar amonizado com uréia.
Resumo: O trabalho foi desenvolvido objetivando-se avaliar o efeito da adição de uréia em doses crescentes, na presença ou ausência de urease, sobre o valor nutritivo do bagaço de cana-de-açúcar. O delineamento experimental foi inteiramente casualizado em arranjo fatorial (4 x 2) + 1 (controle), com quatro repetições. Os fatores avaliados foram nÃveis de uréia (2,0; 4,0; 6,0; e 8,0% da matéria seca), nÃveis de urease (presença, 20,0% da matéria fresca da uréia, e ausência) e um tratamento controle (0,0% de uréia e ausência de urease). Houve efeito da adição de uréia (63,3%) em relação ao controle (69,6%) e efeito da presença de urease (64,4%) em relação à sua ausência (62,1%), para o teor de matéria seca (MS). O menor teor de MS (62,5%) foi observado no nÃvel de 6,2% de uréia. O teor de proteÃna bruta (PB) cresceu linearmente com a adição de uréia (12,0%) em relação ao controle (1,2%), sem urease. O teor de fibra em detergente neutro (FDN) dos materiais amonizados (81,4%) foi menor que o controle (84,7%), com efeito linear negativo das doses crescentes de uréia. Houve teores mais elevados de FDN nos tratamentos com presença de urease (82,1%) em relação aos tratamentos sem a mesma (80,8%). A digestibilidade in vitro da matéria seca (DIVMS) média do tratamento controle (23,2%) foi inferior à DIVMS média dos tratamentos com uréia (28,5%), com efeito linear positivo dos nÃveis crescentes de uréia. Não houve efeito da urease sobre a DIVMS do bagaço. A amonização com uréia melhorou o valor nutritivo do bagaço de cana-de-açúcar, sem a necessidade de adição de urease. [Evaluation of the Nutritive Value of Sugarcane Bagasse Ammoniated with Urea]. Abstract: The objective of this work was to evaluate the effect of the addition of crescent levels of urea, with or without urease, on sugarcane bagasse nutritive value. The experimental design was a completely randomized design in a factorial arrangement (4 x 2) + 1 (control), with four replicates. The evaluated factors were urea levels (2.0, 4.0, 6.0 and 8.0% DM), urease levels (presence - 20% of urea fresh matter - and absence) and a control treatment (0.0% urea and without urease). There was an effect of urea addition (63.3%) on the control (69.6%) and effect of urease presence (64.4%) on its absence (62.1%) for the dry matter (DM) content. The smallest estimated DM content (62.5%) was observed at 6.2% urea level. The crude protein (CP) content linearly increased with the addition of crescentlevels of urea (12.0%) as compared to the control (1.2%), without urease effect. The neutral detergent fiber (NDF) content of ammoniated materials (81.4%) was smaller than the control (84.7%), with a negative linear effect of the crescent levels of urea. There was higher NDF content in the treatments with the presence of urease (82.1%) than on the treatments without urease (80.8%). The average in vitro dry matter disappearance (IVDMD) of the control treatment (23.2%) was lower than average urea addition treatments (28.5%), with positive linear effect by the crescent addition of the urea levels. There was no urease effect on IVDMD. The ammoniation with urea improved the sugar cane bagasse nutritive value, without necessity to add urease
Propagating Torsion in 3D-Gravity and Dynamical Mass Generation
In this paper, fermions are minimally coupled to 3D-gravity where a dynamical
torsion is introduced. A Kalb-Ramond field is non-minimally coupled to these
fermions in a gauge-invariant way. We show that a 1-loop mass generation
mechanism takes place for both the 2-form gauge field and the torsion. As for
the fermions, no mass is dynamically generated: at 1-loop, there is only a mass
shift proportional to the Yukawa coupling whenever the fermions have a
non-vanishing tree-level mass.Comment: 13 pages, latex file, no figures, some corrections adde
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