Quark matter revisited with non extensive MIT bag model

In this work we revisit the MIT bag model to describe quark matter within both the usual Fermi-Dirac and the Tsallis statistics. We verify the effects of the non-additivity of the latter by analysing two different pictures: the first order phase transition of the QCD phase diagram and stellar matter properties. While, the QCD phase diagram is visually affected by the Tsallis statistics, the resulting effects on quark star macroscopic properties are barely noticed.Comment: 10 pagens, 5 figure

Compactlike kinks and vortices in generalized models

This work deals with the presence of topological defects in k-field models, where the dynamics is generalized to include higher order power in the kinetic term. We investigate kinks in (1,1) dimensions and vortices in (2,1) dimensions, focusing on some specific features of the solutions. In particular, we show how the kinks and vortices change to compactlike solutions, controlled by the parameter used to introduce the generalized models.Comment: 7 pages, 7 figures. Version to be published in PR

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

More Discriminants with the Brezing-Weng Method

The Brezing-Weng method is a general framework to generate families of pairing-friendly elliptic curves. Here, we introduce an improvement which can be used to generate more curves with larger discriminants. Apart from the number of curves this yields, it provides an easy way to avoid endomorphism rings with small class number

Melhoramento genético e produção de rainhas de Apis mellifera.

bitstream/item/87876/1/MELHORAMENTO-GENETICO.pd

Downside risk in reservoir management

Downside risk, which refers to deviations below a threshold, is often important in water management decisions, especially in areas with large and skewed variations in precipitation patterns. In this paper, we present a model for a reservoir manager who is downside risk averse and who performs a dynamic allocation of irrigation water, taking into account the negative effects of droughts on farm profits and different environmental constraints. We analyse the water stock, flows and agricultural profits for alternative environmental restrictions and thresholds for irrigation levels and find that stricter environmental constraints increase total water supply and carryover stock, while higher penalty thresholds lead to their overall decrease. Furthermore, increasing penalty thresholds leads to a higher emphasis on avoiding shortages, at the expense of lower average profits.info:eu-repo/semantics/acceptedVersio

Relativistic Mean Field Approximation in a Density Dependent Parametrization Model at Finite Temperature

In this work we calculate the equation of state of nuclear matter for different proton fractions at zero and finite temperature within the Thomas Fermi approach considering three different parameter sets: the well-known NL3 and TM1 and a density dependent parametrization proposed by Typel and Wolter. The main differences are outlined and the consequences of imposing beta-stability in these models are discussed.Comment: 13 pages, 10 figure

Detrended Fluctuation Analysis of Systolic Blood Pressure Control Loop

We use detrended fluctuation analysis (DFA) to study the dynamics of blood pressure oscillations and its feedback control in rats by analyzing systolic pressure time series before and after a surgical procedure that interrupts its control loop. We found, for each situation, a crossover between two scaling regions characterized by exponents that reflect the nature of the feedback control and its range of operation. In addition, we found evidences of adaptation in the dynamics of blood pressure regulation a few days after surgical disruption of its main feedback circuit. Based on the paradigm of antagonistic, bipartite (vagal and sympathetic) action of the central nerve system, we propose a simple model for pressure homeostasis as the balance between two nonlinear opposing forces, successfully reproducing the crossover observed in the DFA of actual pressure signals