SEMCIÊNCIA

Enviado por Roberto Takata: Quantifying the Performance of Individual Players in a Team Activity Jordi Duch 1 , 2 , 3 ,  Joshua S. Waitzman 1 ,  Luís A. Nunes Amaral 1 , 2 , 4 * Background Teamwork is a fundamental aspect of many human activities, from business to art and from sports to science. Recent research suggest that team work is of crucial importance to cutting-edge scientific research, but little is known about how teamwork leads to greater creativity. Indeed, for many team activities, it is not even clear how to assign credit to individual team members. Remarkably, at least in the context of sports, there is usually a broad consensus on who are the top performers and on what qualifies as an outstanding performance. Methodology/Principal Findings In order to determine how individual features can be quantified, and as a test bed for other team-based human activities, we analyze the performance of players in the European Cup 2008 soccer tournament. We develop a network approach ...

Patterns of Prostitution Captured in Social Network Posted: 17 Mar 2010 09:10 PM PDT The patterns of links between buyers and sellers of sex in an online forum differs in important ways from other internet related networks, says a new study. This may have important implications for the spread of sexually transmitted diseases "Over the past decade, the Internet has become an increasingly important vehicle for sharing information about prostitution," say Luis Rocha at Umea University in Sweden and a couple of buddies. That makes it possible to study the network of links between buyers and sellers at a level of detail that has never been possible before. Today, Rocha and co reveal the results one such study of prostitute-related activity in Brazil. The community they look at is a public online forum with free registration, financed by advertisements, in which men grade and categorise their sexual encounters with female escorts. The community appears large with over 10,000 buyers...

Hirsch index as a network centrality measure Monica G. Campiteli , Adriano J. Holanda , Paulo R. C. Soles , Leonardo H. D. Soares , Osame Kinouchi (Submitted on 26 May 2010) We study the h Hirsch index as a local node centrality measure for complex networks in general. The h index is compared with the Degree centrality (a local measure), the Betweenness and Eigenvector centralities (two non-local measures) in the case of a biological network (Yeast interaction protein-protein network) and a linguistic network (Moby Thesaurus II) as test environments. In both networks, the Hirsch index has poor correlation with Betweenness centrality but correlates well with Eigenvector centrality, specially for the more important nodes that are relevant for ranking purposes, say in Search Machine Optimization. In the thesaurus network, the h index seems even to outperform the Eigenvector centrality measure as evaluated by simple linguistic criteria. Comments: 7 pages, 4 figures Subjects: Physics and So...

The Global Shipping Network Revealed Posted: 14 Jan 2010 09:10 PM PST Despite carrying 90 per cent of the planet's trade, nobody has mapped the network of links between the world's ports. Until now. The International Maritime Organization based in London estimates that 90 per cent of the world's trade is moved around the planet by sea. Given the fascination that complexity scientists have with rail, air and road networks, it seems strange that so little attention has been paid to the maritime network. That's a wrong that's put right today by Pablo Kaluza and pals at Carl von Ossietzky University in Oldenburg, Germany. These guys have used the itineraries of 16,363 cargo ships during 2007 to construct a network of links between the world's top 951 ports. The results, at least in part, are eyebrow raising. First, the unsurprising news. Kaluza and co show that these links form a small world network in which it is easy to move from one port to another in a small nu...

Está fundado o Laboratório de Física Estatística e Biologia Computacional (FEBiC), onde os coordenadores são os Profs. Ubiraci P. C. Neves e Osame Kinouchi Filho, do DFM-FFCLR-USP. Se você está pensando em pós-graduação ou pós-doutorado e tiver interesse em nossas linhas de pesquisa (ver aqui e aqui), por favor entre em contato! Edital de Abertura de Inscrição na Pós-Graduação em Física Aplicada à Medicina e Biologia Serviço de Pós-Graduação Período de Inscrição: 08/04/2010 a 02/07/2010

Copiando descaradamento do Fuinha, via uma twittada do Cardoso , mas fazendo um reparo: Fuinha, o PR não é apenas uma contagem de links, mas sim se baseia no conceito de ce ntralidade de autovetor, onde o seu PR é a soma ponderada do PR de seus citadores . Isso é calculado por um algoritmos iterativo que trabalha com matrizes enormes, e é por isso que a mediada é computacionalmente intensiva. Quem sabe, o meu índice h de redes complexas, se tiver boa correlção com o PR, possa vir a complementá-lo um dia, ou ser usado por quem não tem acesso ao banco de dados da Google... Ter um PageRank alto , é o sonho que todo blogueiro. Ser bem visto pelos buscadores, pode lhe trazer ótimos resultados financeiros, e também um grande reconhecimento de toda a blogosfera. Resumidamente , o que determina o PageRank do seu site/blog é quantidade de links de outros sites que levam até sua página. Cada link que você recebe, conta como um voto, quanto mais link, mais votos, e assim seu site ganha relevânci...

Googling Food Webs : Can an Eigenvector Measure Species' Importance for Coextinctions? Article Related Content Comments: 0 To add a note , highlight some text. Hide notes Make a general comment Jump to Abstract Author Summary Introduction Materials and Methods Results Discussion Supporting Information Acknowledgments Author Contributions References Stefano Allesina 1 * , Mercedes Pascual 2 , 3 , 4 1 National Center for Ecological Analysis and Synthesis, Santa Barbara, California, United States of America, 2 Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, United States of America, 3 Santa Fe Institute, Santa Fe, New Mexico, United States of America, 4 Howard Hughes Medical Institute Abstract Top A major challenge in ecology is forecasting the effects of species' extinctions, a pressing problem given current human impacts on the planet. Consequences of species losses such as secondary extinctions are difficult to forecast because s...

Ver reviews aqui . Handbook of Computational Economics: Agent-Based Computational Economics (Handbook of Computational Economics S.) Judd, K.L., Tesfatsion, L., Intriligator, M.D. and Arrow, Kenneth J. (eds.) Reviewed by Herbert Gintis Not by Genes Alone: How Culture Transformed Human Evolution Richerson, Peter J. and Boyd, Robert Reviewed by Giangiacomo Bravo Biology, Sociology, Geology by Computational Physicists (Monograph Series on Nonlinear Science and Complexity) Stauffer, Dietrich, Oliveira, Suzana Moss de, Oliveira, Paulo Murilo Castro de and Martins, Jorge Simoes de Sa Reviewed by Frank Schweitzer Complexity and Co-Evolution: Continuity and Change in Socio-Economic Systems Garnsey, Elizabeth, Hall Clare, McGlade, James Reviewed by Mauro Lombardi The Re-Emergence of Emergence: the Emergentist Hypothesis from Science to Religion Clayton, Philip and Davies, Paul (eds.) Reviewed by Johannes Lenhard Computer Simulations of Criminal Deterrence: from Public Policy to Local Interac...

Proponho um novo índice de centralidade social: o Obama Number (ON). Corresponde ao menor caminho na série de apertos de mão até Obama. Eu pensava que tinha ON igual a quatro: apertei a mão do Sidarta Ribeiro, que apertou a mão do Miguel Nicolelis, que apertou a mão do Lula que apertou a mão do Obama. (Minha filha Mariana me disse: "Então aperte a minha mão!") Mas daí lembrei que apertei a mão do Silvio Salinas, que apertou a mão do Lula, que apertou a mão do Obama, logo tenho ON = 3. Preciso verificar se a Natalie Portman apertou a mão do Obama (o que é provável , dada esta foto). Já pensou? Quatro graus de separação da Natalie Portman!

Enviado pelo Sandro Reia: Professor, achei um post bem legal: quando o senhor puder dá uma olhada: http://vivoeduca.ning.com/profiles/blogs/textos-sobre-redes-sociais