A Simple Non-Markovian Computational Model of the Statistics of Soccer Leagues: Emergence and Scaling effects

We propose a novel algorithm that outputs the final standings of a soccer league, based on a simple dynamics that mimics a soccer tournament. In our model, a team is created with a defined potential(ability) which is updated during the tournament according to the results of previous games. The updated potential modifies a teams' future winning/losing probabilities. We show that this evolutionary game is able to reproduce the statistical properties of final standings of actual editions of the Brazilian tournament (Brasileir\~{a}o). However, other leagues such as the Italian and the Spanish tournaments have notoriously non-Gaussian traces and cannot be straightforwardly reproduced by this evolutionary non-Markovian model. A complete understanding of these phenomena deserves much more attention, but we suggest a simple explanation based on data collected in Brazil: Here several teams were crowned champion in previous editions corroborating that the champion typically emerges from random fluctuations that partly preserves the gaussian traces during the tournament. On the other hand, in the Italian and Spanish leagues only a few teams in recent history have won their league tournaments. These leagues are based on more robust and hierarchical structures established even before the beginning of the tournament. For the sake of completeness, we also elaborate a totally Gaussian model (which equalizes the winning, drawing, and losing probabilities) and we show that the scores of the "Brasileir\~{a}o" cannot be reproduced. Such aspects stress that evolutionary aspects are not superfluous in our modeling. Finally, we analyse the distortions of our model in situations where a large number of teams is considered, showing the existence of a transition from a single to a double peaked histogram of the final classification scores. An interesting scaling is presented for different sized tournaments.Comment: 18 pages, 9 figure

Characterizing and modeling preferential flow using magnetic resonance imaging and multifractal theory.

bitstream/item/89956/1/Proci-07.00331.PD

Ac transport studies in polymers by a resistor network and transfer matrix approaches: application to polyaniline

A statistical model of resistor network is proposed to describe a polymer structure and to simulate the real and imaginary components of its ac resistivity. It takes into account the polydispersiveness of the material as well as intrachain and interchain charge transport processes. By the application of a transfer matrix technique, it reproduces ac resistivity measurements carried out with polyaniline films in different doping degrees and at different temperatures. Our results indicate that interchain processes govern the resistivity behavior in the low frequency region while, for higher frequencies, intrachain mechanisms are dominant.Comment: LaTeX file, 15 pages, 5 ps figures, to appear in Phys. Rev.

Levantamento de himenópteros parasitoides na agricultura Kaxinawá de Nova Olinda, Feijó, AC.

O conhecimento acerca do ciclo de vida, bem como seus nichos e inimigos naturais de insetos-praga, podem trazer soluções para um controle racional e adequado. O levantamento de insetos, especialmente os himenópteros parasitoides, é importante para o conhecimento da entomofauna de determinada região, bem como na busca de inimigos naturais que possam ser utilizados em programas de controle biológico. Em uma agricultura de base agroecológica (sem utilização de agrotóxicos), como é a praticada pelos Kaxinawá, o controle biológico exerce papel fundamental na regulação de insetos-praga. O estudo foi conduzido na aldeia Porto Alegre, terra indígena Kaxinawá, Feijó, AC

Exact Solution of an Evolutionary Model without Ageing

We introduce an age-structured asexual population model containing all the relevant features of evolutionary ageing theories. Beneficial as well as deleterious mutations, heredity and arbitrary fecundity are present and managed by natural selection. An exact solution without ageing is found. We show that fertility is associated with generalized forms of the Fibonacci sequence, while mutations and natural selection are merged into an integral equation which is solved by Fourier series. Average survival probabilities and Malthusian growth exponents are calculated indicating that the system may exhibit mutational meltdown. The relevance of the model in the context of fissile reproduction groups as many protozoa and coelenterates is discussed.Comment: LaTeX file, 15 pages, 2 ps figures, to appear in Phys. Rev.

Dynamics of tournaments: the soccer case

A random walk-like model is considered to discuss statistical aspects of tournaments. The model is applied to soccer leagues with emphasis on the scores. This competitive system was computationally simulated and the results are compared with empirical data from the English, the German and the Spanish leagues and showed a good agreement with them. The present approach enabled us to characterize a diffusion where the scores are not normally distributed, having a short and asymmetric tail extending towards more positive values. We argue that this non-Gaussian behavior is related with the difference between the teams and with the asymmetry of the scores system. In addition, we compared two tournament systems: the all-play-all and the elimination tournaments.Comment: To appear in EPJ

Ichneumonidae (Hymenoptera) capturados em armadilhas Malaise, em Rio Branco, AC.

A ordem Hymenoptera abriga espécies com hábitos parasitas ou predadores de outros insetos e, ainda, espécies polinizadoras de plantas. Constituem um grupo muito diversificado no que tange aos hábitos alimentares e comportamentais. As vespas parasitoides participam em mais de 50% das cadeias alimentares dos ambientes terrestres. A família Ichneumonidae é uma das maiores entre os Insecta, com aproximadamente 60.000 espécies descritas, sendo cerca de 17.000 na região Neotropical. Embora sua importância seja evidente, estudos da biodiversidade de parasitoides na região amazônica são escassos. Neste sentido, o objetivo deste levantamento foi aumentar o conhecimento sobre a fauna de Ichneumonidae no estado do Acre. Foram instaladas duas armadilhas Malaise (uma na bordadura e outra no interior) em um remanescente florestal, localizado no município de Rio Branco, AC. Semanalmente os frascos coletores, contendo álcool a 90%, eram recolhidos e trocados por novos. O material foi triado em laboratório e os parasitoides identificados em nível de subfamília, sob microscópio estereoscópio. A armadilha localizada na bordadura capturou 133 parasitoides de 13 subfamílias, enquanto a localizada no interior da mata capturou 210, de 15 subfamílias. As principais subfamílias foram Cryptinae e Cremastinae, correspondendo a aproximadamente 75% de todos os parasitoides capturados neste levantamento