Scalar Field Dark Matter: behavior around black holes

We present the numerical evolution of a massive test scalar fields around a Schwarzschild space-time. We proceed by using hyperboloidal slices that approach future null infinity, which is the boundary of scalar fields, and also demand the slices to penetrate the event horizon of the black hole. This approach allows the scalar field to be accreted by the black hole and to escape toward future null infinity. We track the evolution of the energy density of the scalar field, which determines the rate at which the scalar field is being diluted. We find polynomial decay of the energy density of the scalar field, and use it to estimate the rate of dilution of the field in time. Our findings imply that the energy density of the scalar field decreases even five orders of magnitude in time scales smaller than a year. This implies that if a supermassive black hole is the Schwarzschild solution, then scalar field dark matter would be diluted extremely fastComment: 15 pages, 21 eps figures. Appendix added, accepted for publication in JCA

Anisotropic quark stars with an interacting quark equation of state

A deep exploration of the parameter space that relates the interacting equation of state with the bag constant B, and the interaction parameter a, is fundamental for the construction of diverse models of quark stars. In particular, the anisotropy of quark stars with a well-motivated quantum chromodynamics (QCD) equation of state is presented here. The contribution of the fourth order corrections parameter (a4) of the QCD perturbation on the radial and tangential pressure generate significant effects on the mass-radius relation and the stability of the quark star. An adequate set of solutions for several values of the bag factor and the interaction parameter are used in order to calculate the relation between the mass, radius, density, compactness, and consequently the maximum masses and the stability. Therefore, while the more interactive quark solution leads to higher masses, the weak interaction among quarks gives solutions similar to the widely known MIT bag model

PRODUCCIÓN DE TOMATE EN INVERNADERO CON COMPOSTA Y VERMICOMPOSTA COMO SUSTRATO

The organic production of food is an alternative for consumers that prefer food free of pesticides, synthetic fertilisers, and with a high nutritional value. The purpose of this study was to evaluate substrates prepared with mixtures of compost and vermicompost with sand, at various levels, under greenhouse conditions. The tomato hybrid SUN-7705 (Lycopersicon esculentum Mill) was analized in four substrates that included compost and vermicompost mixed at three different proportions (100, 75 y 50 %). The treatments were distributed in a completely randomised design with a factorial arrangement of 4x3 and five replicates. The greatest average yield (39.811 t ha) was obtained with the compost generated by decomposing bovine manure, corn stover (Zea mays L.), elephant grass (Pennisetum purpureum Schumacher) and black earth (CEMZT) at 75% + sand, and with the vermicompost generated by manure, bahiagrass (Paspalum notatum Flügge) and black earth (VEPT) at 100 and 50% + sand. This yield was greater than that recorded for organic tomato production in the field, without affecting the quality of the fruit