3,841 research outputs found

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

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    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

    The Incidence of Lead Shot in Waterfowl of the Pacific Flyway, With Special Reference to the Great Salt Lake Basin

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    This study was conducted to determine basic data on the incidence of lead shot in ducks us ing the Great Salt Le.lee Basin. The study has been divided into two parts; (1) incidence of ducks carrying lead shot in their tissues and (2) incidenoe of ducks carrying ingested lead shot

    Local Properties of the Potential Energy Landscape of a Model Glass: Understanding the Low Temperature Anomalies

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    Though the existence of two-level systems (TLS) is widely accepted to explain low temperature anomalies in the sound absorption, heat capacity, thermal conductivity and other quantities, an exact description of their microscopic nature is still lacking. We performed computer simulations for a binary Lennard-Jones system, using a newly developed algorithm to locate double-well potentials (DWP) and thus two-level systems on a systematic basis. We show that the intrinsic limitations of computer simulations like finite time and finite size problems do not hamper this analysis. We discuss how the DWP are embedded in the total potential energy landscape. It turns out that most DWP are connected to the dynamics of the smaller particles and that these DWP are rather localized. However, DWP related to the larger particles are more collective

    Loss of control in pattern-directed nucleation: a theoretical study

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    The properties of template-directed nucleation are studied close to the transition where full nucleation control is lost and additional nucleation occurs beyond the pre-patterned regions. First, kinetic Monte Carlo simulations are performed to obtain information on a microscopic level. Here the experimentally relevant cases of 1D stripe patterns and 2D square lattice symmetry are considered. The nucleation properties in the transition region depend in a complex way on the parameters of the system, i.e. the flux, the surface diffusion constant, the geometric properties of the pattern and the desorption rate. Second, the properties of the stationary concentration field in the fully controlled case are studied to derive the remaining nucleation probability and thus to characterize the loss of nucleation control. Using the analytically accessible solution of a model system with purely radial symmetry, some of the observed properties can be rationalized. A detailed comparison to the Monte Carlo data is included

    Non Markovian persistence in the diluted Ising model at criticality

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    We investigate global persistence properties for the non-equilibrium critical dynamics of the randomly diluted Ising model. The disorder averaged persistence probability Pcˉ(t)\bar{{P}_c}(t) of the global magnetization is found to decay algebraically with an exponent θc\theta_c that we compute analytically in a dimensional expansion in d=4−ϵd=4-\epsilon. Corrections to Markov process are found to occur already at one loop order and θc\theta_c is thus a novel exponent characterizing this disordered critical point. Our result is thoroughly compared with Monte Carlo simulations in d=3d=3, which also include a measurement of the initial slip exponent. Taking carefully into account corrections to scaling, θc\theta_c is found to be a universal exponent, independent of the dilution factor pp along the critical line at Tc(p)T_c(p), and in good agreement with our one loop calculation.Comment: 7 pages, 4 figure

    Origin of non-exponential relaxation in a crystalline ionic conductor: a multi-dimensional 109Ag NMR study

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    The origin of the non-exponential relaxation of silver ions in the crystalline ion conductor Ag7P3S11 is analyzed by comparing appropriate two-time and three-time 109Ag NMR correlation functions. The non-exponentiality is due to a rate distribution, i.e., dynamic heterogeneities, rather than to an intrinsic non-exponentiality. Thus, the data give no evidence for the relevance of correlated back-and-forth jumps on the timescale of the silver relaxation.Comment: 4 pages, 3 figure
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