Sérgio Furtado dos Reis

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Mutualistic networks involving plants and their pollinators or frugivores have been shown recently to exhibit a particular asymmetrical organization of interactions among species called nestedness: a core of reciprocal generalists accompanied by specialist species that interact almost exclusively with generalists. This structure contrasts with(More)
Barabasi-Albert networks are constructed by adding nodes via preferential attachment to an initial core of nodes. We study the topology of small scale-free networks as a function of the size and average connectivity of their initial random core. We show that these two parameters may strongly affect the tail of the degree distribution, by consistently(More)
The computationally challenging problem of reconstructing the phylogeny of a set of contemporary data, such as DNA sequences or morphological attributes, was treated by an extended version of the neighbor-joining (NJ) algorithm. The original NJ algorithm provides a single-tree topology, after a cascade of greedy pairing decisions that tries to(More)
Poecilia vivipara is a small fish found throughout the coastal lowlands of South America. We report the isolation and characterization of 25 microsatellite loci in this tropical fish. In 24 individuals from two populations, 18 loci were polymorphic. The loci had 2–12 alleles, expected heterozygosities of 0.194–0.836, observed heterozygosities of(More)
In this paper, we present a new shape analysis approach using the well-known wavelet transform and exploring shape representation by landmarks. First, we describe the approach adopted to represent the landmarks data as parametric signals. Then, we show the relation of the derivatives of Gaussian wavelet transform applied to the signal-to-differential(More)
This paper presents the main steps to reconstruct phylogenetic trees using an evolutionary algorithm with a wide range of alternative computational procedures for fitness evaluation and for tuning the search engine. Due to the fine equilibrium between exploration and exploitation of the search space, high-quality reconstructions are obtained among an(More)
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