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ABSTRACT: Nowadays there is an increasing interest of physicists in finding
regularities related to social phenomena. This interest is clearly motivated by
applications that a statistical mechanical description of the human behavior
may have in our society. By using this framework, we address this work to cover
an open question related to elections: the choice of elections candidates
(candidature process). Our analysis reveals that, apart from the social
motivations, this system displays features of traditional out-of-equilibrium
physical phenomena such as scale-free statistics and universality. Basically,
we found a non-linear (power law) mean correspondence between the number of
candidates and the size of the electorate (number of voters), and also that
this choice has a multiplicative underlying process (lognormal behavior). The
universality of our findings is supported by data from 16 elections from 5
countries. In addition, we show that aspects of network scale-free can be
connected to this universal behavior.
09/2011;
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ABSTRACT: We report remarkable similarities in the output signal of two distinct out-of- equilibrium physical systems - earthquakes and the intermittent acoustic noise emitted by crum- pled plastic sheets - Biaxially Oriented Polypropylene (BOPP) films. We show that both signals share several statistical properties including the distribution of energy, distribution of energy in- crements for distinct time scales, distribution of return intervals and correlations in the magnitude and sign of energy increments. This analogy is consistent with the concept of universality in com- plex systems and could provide some insight on the mechanisms behind the complex behavior of earthquakes.
11/2010;
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ABSTRACT: 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 EPJB
01/2010;
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ABSTRACT: We analyze the dynamics of a widely used measure of geomagnetic activity —the Dst index— and compare our findings with those found in healthy human heartbeat dynamics. We show that the Dst index belongs to a special class of complex signals, exhibiting long-range temporal correlations, multifractality and scale-invariant distribution. Specifically, we find that i) Dst series and magnitude series of Dst increments are long-range correlated while the sign series of Dst increments is anti-correlated; ii) the scaling exponents that govern these temporal correlations increase with geomagnetic activity; iii) Dst series exhibit multifractal behavior; iv) the multifractal spectra that characterize Dst series are practically independent of the geomagnetic activity; and v) the distribution of Dst increments exhibits scale invariance at a wide range of time scales. These results are in surprising agreement with those found in the study of heartbeat intervals. Our findings are consistent with the concept of universality in complex systems and may contribute to a better understanding of the mechanisms that govern geomagnetic activity.
EPL (Europhysics Letters) 10/2007; 80(5):50006. · 2.17 Impact Factor
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ABSTRACT: We analyze data sets containing the circulation of magazines and newspapers. We show that the cumulative distribution follows, in the range of large circulation, a power law behavior whose exponent is μ 1.5; and deviations from the asymptotic power law behavior can be well described by a q-exponential distribution (Zipf-Mandelbrot law) from Tsallis statistics. We also show that, in the range of large circulation, the distribution of logarithmic growth rates is consistent with an exponential; and the standard deviation of the growth rates is practically independent of the circulation (size). Moreover, we employ a model, inspired in one of the simplest model for firm growth, in order to reproduce some of our findings.
EPL (Europhysics Letters) 01/2007; 72(5):865. · 2.17 Impact Factor
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ABSTRACT: In a comparative study, the q-exponential and Weibull distributions are employed to investigate frequency distributions of basketball baskets, cyclone victims, brand-name drugs by retail sales, and highway length. In order to analyze the intermediate cases, a distribution, the q-Weibull one, which interpolates the q-exponential and Weibull ones, is introduced. It is verified that the basketball baskets distribution is well described by a q-exponential, whereas the cyclone victims and brand-name drugs by retail sales ones are better adjusted by a Weibull distribution. On the other hand, for highway length the q-exponential and Weibull distributions do not give satisfactory adjustment, being necessary to employ the q-Weibull distribution. Furthermore, the introduction of this interpolating distribution gives an illumination from the point of view of the stretched exponential against inverse power law (q-exponential with q > 1) controversy. Comment: 6 pages, Latex. To appear in Physica A
01/2003;
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ABSTRACT: We analyze a database comprising the impact factor (citations per recent items published) of scientific journals for a 13-year period (1992–2004). We find that i) the distribution of impact factors follows asymptotic power law behavior, ii) the distribution of annual logarithmic growth rates has an exponential form, and iii) the width of this distribution decays with the impact factor as a power law with exponent $\beta\simeq 0.22$. The results ii) and iii) are surprising similar to those observed in the growth dynamics of organizations with complex internal structure suggesting the existence of common mechanisms underlying the dynamics of these systems. We propose a general model for such systems, an extension of the simplest model for firm growth, and compare their predictions with our empirical results.
http://dx.doi.org/10.1209/epl/i2006-10162-1.
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ABSTRACT: In this work, we address modal parameter fluctuations in statistical distributions describing charge-to-breakdown (QBD) and/or time-to-breakdown (tBD) during the dielectric breakdown regime of ultra-thin oxides, which are of high interest for the advancement of electronic technology. We reobtain a generalized Weibull distribution (q-Weibull), which properly describes (tBD) data when oxide thickness fluctuations are present, in order to improve reliability assessment of ultra-thin oxides by time-to-breakdown (tBD) extrapolation and area scaling. The incorporation of fluctuations allows a physical interpretation of the q-Weibull distribution in connection with the Tsallis statistics. In support to our results, we analyze tBD data of SiO2-based MOS devices obtained experimentally and theoretically through a percolation model, demonstrating an advantageous description of the dielectric breakdown by the q-Weibull distribution.
Physica A: Statistical Mechanics and its Applications.
