The importance of the mixed phase in hybrid stars built with the Nambu-Jona-Lasinio model

We investigate the structure of hybrid stars based on two different constructions: one is based on the Gibbs condition for phase coexistence and considers the existence of a mixed phase (MP), and the other is based on the Maxwell construction and no mixed phase is obtained. The hadron phase is described by the non-linear Walecka model (NLW) and the quark phase by the Nambu-Jona-Lasinio model (NJL). We conclude that the masses and radii obtained are model dependent but not significantly different for both constructions.Comment: 8 pages, 7 figures, 3 table

Evolution of the fine-structure constant in the non-linear regime

We study the evolution of the fine-structure constant, $\alpha$, induced by non-linear density perturbations in the context of the simplest class of quintessence models with a non-minimal coupling to the electromagnetic field, in which the two available free functions (potential and gauge kinetic function) are Taylor-expanded up to linear order. We show that the results obtained using the spherical infall model for an infinite wavelength inhomogeneity are inconsistent with the results of a local linearized gravity study and we argue in favour of the second approach. We also discuss recent claims that the value of $\alpha$ inside virialised regions could be significantly different from the background one on the basis of these findings.Comment: 5 pages, 3 figure

First-order transition in small-world networks

The small-world transition is a first-order transition at zero density $p$ of shortcuts, whereby the normalized shortest-path distance undergoes a discontinuity in the thermodynamic limit. On finite systems the apparent transition is shifted by $\Delta p \sim L^{-d}$. Equivalently a ``persistence size'' $L^* \sim p^{-1/d}$ can be defined in connection with finite-size effects. Assuming $L^* \sim p^{-\tau}$, simple rescaling arguments imply that $\tau=1/d$. We confirm this result by extensive numerical simulation in one to four dimensions, and argue that $\tau=1/d$ implies that this transition is first-order.Comment: 4 pages, 3 figures, To appear in Europhysics Letter

Estimativa do Albedo em áreas de pastagem e floresta no Mato Grosso do Sul.

O albedo é um parâmetro fundamental em vários estudos do clima e está diretamente ligado com o balanço de energia em escala local, regional e global. Esta pesquisa objetivou a estimativa do albedo em áreas de pastagem e floresta com aplicação do algoritmo SEBAL e imagens do sensor TM do satélite Landsat 5. Nas áreas de pastagem o albedo médio foi de 0,23 e 0,22, enquanto nas áreas de floresta foi de 0,18 e 0,17, para as cenas dos dias 05/03/2008 e 08/03/2009, respectivamente

Impact of Increasing Nitrogen Fertilizer Rates upon an Irrigated Tanzania Grass Pasture. 1. Dry Matter Yield

An experiment was carried out with irrigated Tanzania grass (Panicum maximum, Jacq.) pasture receiving five nitrogen (N) rates of (0, 30, 60, 90 and 120 kg N ha-¹ cut-¹) during the growing season. N application increased dry matter yield and Tanzania growth rate linearly (P \u3c 0.05). Responses to nitrogen applications were higher in the first two cuts of the growing season than in the last two cuts. The N fertilizer conversion into herbage dry matter was also higher in the beginning of the growing season

Typification and taxonomic status re-eveluation of 15 taxon names within the species complex Cymbella affinis/tumidula/turgidula (Cymbellaceae, Bacillariophyta)

Volume: 53Start Page: 1End Page: 2