Braneworld cosmology in f(R,T)f(R,T) gravity

Braneworld scenarios consider our observable universe as a brane embedded in a 5D space, named bulk. In this work, I derive the field equations of a braneworld model in a generalized theory of gravitation, namely $f(R,T)$ gravity, with $R$ and $T$, representing the Ricci scalar and the trace of the energy-momentum tensor, respectively. The cosmological parameters obtained from this approach are in agreement with recent constraints from Supernovae Ia data combined with baryon acoustic oscillations and cosmic microwave background observations, favouring such an alternative description of the universe dynamics.Comment: 6 pages, 1 figur

Wormholes in R2R^2-gravity within the f(R,T)f(R,T) formalism

We propose, as a novelty in the literature, the modelling of wormholes within the particular case of the $f(R,T)$ gravity, namely $f(R,T)=R+\alpha R^{2}+\lambda T$, with $R$ and $T$ being the Ricci scalar and trace of the energy-momentum tensor, respectively, while $\alpha$ and $\lambda$ are constants. Although such a functional form application can be found in the literature, those concern to compact astrophysical objects, such that no wormhole analysis has been done so far. The quadratic geometric and linear material corrections of this theory make the matter content of the wormhole to remarkably be able to obey the energy conditions.Comment: Published versio

Pastagens implantadas no Pantanal nas décadas de 1960 a 1990.

Dados primários sobre a pecuária pantaneira foram obtidos mediante aplicação de um questionário, que levantou informações sobre os sistemas de produção em uso na região, e em particular, sobre a implantação de pastagens cultivadas. Os questionários foram enviados via correio, seguindo convenções metodológicas. Desde o início dos anos 1970 os fazendeiros do Pantanal têm desmatado e plantado a fim de aumentar a capacidade de suporte anual da terra para o gado. Entretanto, o desmatamento para a introdução de pastagens além de aumentar a produtividade do rebanho pode, ao mesmo tempo, causar impactos negativos no ecossistema