%A Vinko Zlatic %A Ginestra Bianconi %A Albert D?az-Guilera %A Diego Garlaschelli %A Francesco Rao %A Guido Caldarelli %V 67 %J The European Physical Journal B %R 10.1140/epjb/e2009-00007-9 %T On the rich-club effect in dense and weighted networks %K PACS: 89.75.Hc Networks and genealogical trees; 89.75.Fb Structures and organization in complex systems %X For many complex networks present in nature only a single instance, usually of large size, is available. Any measurement made on this single instance cannot be repeated on different realizations. In order to detect significant patterns in a real-world network it is therefore crucial to compare the measured results with a null model counterpart. Here we focus on dense and weighted networks, proposing a suitable null model and studying the behaviour of the degree correlations as measured by the rich-club coefficient. Our method solves an existing problem with the randomization of dense unweighted graphs, and at the same time represents a generalization of the rich-club coefficient to weighted networks which is complementary to other recently proposed ones. %D 2009 %L eprints1091 %P 271-275 %N 3