53,713 research outputs found
On FRW Model in Conformal Teleparallel Gravity
In this paper we use the conformal teleparallel gravity to study an isotropic
and homogeneous Universe which is settled by the FRW metric. We solve the field
equations and we obtain the behavior of some cosmological parameters such as
scale factor, deceleration parameter and the energy density of the perfect
fluid which is the matter field of our model. The field equations, that we
called modified Friedmann equations, allow us to define a dark fluid, with dark
energy density and dark pressure, responsible for the acceleration in the
Universe.Comment: Accepted in EPJ
Copper and Barium Abundances in the Ursa Major Moving Group
We present Cu and Ba abundances for 7 G-K dwarf stars, members of the
solar-metallicity, 0.3 Gyr old Ursa Major Moving Group. All analyzed member
stars show [Ba/Fe] excesses of +0.3-plus, associated with [Cu/Fe] deficiencies
of up to -0.23 dex. The present results suggest that there is an
anti-correlation between the abundances of Cu and the heavy elements produced
by the main component of the neutron capture s-process. Other possible
anomalies are Na and C deficiencies with respect to normal solar-metallicity
stars. The new data do not confirm the recent claim that the group member
HR6094 is a Ba dwarf star.Comment: 8 pages, 6 figures, accepted to MNRA
Real and complex integral closure, Lipschitz equisingularity and applications on square matrices
Recently the authors investigated the Lipschitz triviality of simple germs of
matrices. In this work, we improve some previous results and we present an
extension of an integral closure result for the real setting. These tools are
applied to investigate classes of square matrices singularities classified by
Bruce and Tari
Avaliação da produtividade das ordens primária, secundária e terciária de genótipos de mamoneira de porte baixo em Irecê-BA.
- …