34 research outputs found
Growth patterns and scaling laws governing AIDS epidemic in Brazilian cities
Brazil holds approximately 1/3 of population living infected with AIDS
(acquired immunodeficiency syndrome) in Central and South Americas, and it was
also the first developing country to implement a large-scale control and
intervention program against AIDS epidemic. In this scenario, we investigate
the temporal evolution and current status of the AIDS epidemic in Brazil.
Specifically, we analyze records of annual absolute frequency of cases for more
than 5000 cities for the first 33 years of the infection in Brazil. We found
that (i) the annual absolute frequencies exhibit a logistic-type growth with an
exponential regime in the first few years of the AIDS spreading; (ii) the
actual reproduction number decaying as a power law; (iii) the distribution of
the annual absolute frequencies among cities decays with a power law behavior;
(iv) the annual absolute frequencies and the number of inhabitants have an
allometric relationship; (v) the temporal evolution of the annual absolute
frequencies have different profile depending on the average annual absolute
frequencies in the cities. These findings yield a general quantitative
description of the AIDS infection dynamics in Brazil since the beginning. They
also provide clues about the effectiveness of treatment and control programs
against the infection, that has had a different impact depending on the number
of inhabitants of cities. In this framework, our results give insights into the
overall dynamics of AIDS epidemic, which may contribute to select empirically
accurate models.Comment: 12 pages, 6 figure
Scaling laws and universality in the choice of election candidates
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.Comment: Accepted for publication in EP
An Improved Description of the Dielectric Breakdown in Oxides Based on a Generalized Weibull distribution
In this work, we address modal parameter fluctuations in statistical
distributions describing charge-to-breakdown and/or
time-to-breakdown 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 (-Weibull), which
properly describes data when oxide thickness fluctuations are
present, in order to improve reliability assessment of ultra-thin oxides by
time-to-breakdown extrapolation and area scaling. The incorporation
of fluctuations allows a physical interpretation of the -Weibull
distribution in connection with the Tsallis statistics. In support to our
results, we analyze data of SiO-based MOS devices obtained
experimentally and theoretically through a percolation model, demonstrating an
advantageous description of the dielectric breakdown by the -Weibull
distribution.Comment: 5 pages, 3 figure
Statistical Laws Governing Fluctuations in Word Use from Word Birth to Word Death
We analyze the dynamic properties of 10^7 words recorded in English, Spanish
and Hebrew over the period 1800--2008 in order to gain insight into the
coevolution of language and culture. We report language independent patterns
useful as benchmarks for theoretical models of language evolution. A
significantly decreasing (increasing) trend in the birth (death) rate of words
indicates a recent shift in the selection laws governing word use. For new
words, we observe a peak in the growth-rate fluctuations around 40 years after
introduction, consistent with the typical entry time into standard dictionaries
and the human generational timescale. Pronounced changes in the dynamics of
language during periods of war shows that word correlations, occurring across
time and between words, are largely influenced by coevolutionary social,
technological, and political factors. We quantify cultural memory by analyzing
the long-term correlations in the use of individual words using detrended
fluctuation analysis.Comment: Version 1: 31 pages, 17 figures, 3 tables. Version 2 is streamlined,
eliminates substantial material and incorporates referee comments: 19 pages,
14 figures, 3 table
Evolution of scaling emergence in large-scale spatial epidemic spreading
Background: Zipf's law and Heaps' law are two representatives of the scaling
concepts, which play a significant role in the study of complexity science. The
coexistence of the Zipf's law and the Heaps' law motivates different
understandings on the dependence between these two scalings, which is still
hardly been clarified.
Methodology/Principal Findings: In this article, we observe an evolution
process of the scalings: the Zipf's law and the Heaps' law are naturally shaped
to coexist at the initial time, while the crossover comes with the emergence of
their inconsistency at the larger time before reaching a stable state, where
the Heaps' law still exists with the disappearance of strict Zipf's law. Such
findings are illustrated with a scenario of large-scale spatial epidemic
spreading, and the empirical results of pandemic disease support a universal
analysis of the relation between the two laws regardless of the biological
details of disease. Employing the United States(U.S.) domestic air
transportation and demographic data to construct a metapopulation model for
simulating the pandemic spread at the U.S. country level, we uncover that the
broad heterogeneity of the infrastructure plays a key role in the evolution of
scaling emergence.
Conclusions/Significance: The analyses of large-scale spatial epidemic
spreading help understand the temporal evolution of scalings, indicating the
coexistence of the Zipf's law and the Heaps' law depends on the collective
dynamics of epidemic processes, and the heterogeneity of epidemic spread
indicates the significance of performing targeted containment strategies at the
early time of a pandemic disease.Comment: 24pages, 7figures, accepted by PLoS ON
Statistical properties of the circulation of magazines and newspapers
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 ; 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
A non-Gaussian model in polymeric network
We investigate a finite chain approximation, the non-Gaussian Tsallis distribution, to the polymeric network, which gives an improvement to the Gaussian model. This distribution presents some necessary characteristics, like a cutoff to the maximum chain length and a continuous limit to the Gaussian one for a large number of monomers. It also presents a simple quadratic structure that allows to generalize the Gaussian properties such as exact-moments calculation and Wick theorem. We obtain the free-energy density in its full tensorial structure