Long-range spatial correlations and fluctuation statistics of lightning activity rates in Brazil

Ribeiro, Haroldo V.; Antônio, Fernando; Alves, Luiz G. A.; Lenzi, E. K.; Mendes, R. S.

doi:10.1209/0295-5075/104/69001

Cited by 3 publications

(3 citation statements)

References 34 publications

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“…This equation initially intended to investigate the growth of interfaces [73, 74], but it may be useful to investigate a diffusive process which starts at the origin and grows radially, intermingled with a random noise η (random source). The Edwards-Wilkinson equation was used in the study of other collective phenomena such as elections [75], homicide crimes [76] and lightning activity [77]. Unfortunately, this description is not a sufficient approximation to describe the spreading of an epidemic such as dengue.…”

Section: Discussionmentioning

confidence: 99%

Spatial patterns of dengue cases in Brazil

et al. 2017

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Dengue infection plays a central role in our society, since it is the most prevalent vector-borne viral disease affecting humans. We statistically investigated patterns concerning the spatial spreading of dengue epidemics in Brazil, as well as their temporal evolution in all Brazilian municipalities for a period of 12 years. We showed that the distributions of cases in municipalities follow power laws persistent in time and that the infection scales linearly with the population of the municipalities. We also found that the average number of dengue cases does not have a clear dependence on the longitudinal position of municipalities. On the other hand, we found that the average distribution of cases varies with the latitudinal position of municipalities, displaying an almost constant growth from high latitudes until reaching the Tropic of Capricorn leveling to a plateau closer to the Equator. We also characterized the spatial correlation of the number of dengue cases between pairs of municipalities, where our results showed that the spatial correlation function decays with the increase of distance between municipalities, following a power-law with an exponential cut-off. This regime leads to a typical dengue traveling distance. Finally, we considered modeling this last behaviour within the framework of a Edwards-Wilkinson equation with a fractional derivative on space.

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Section: Discussionmentioning

confidence: 99%

Spatial patterns of dengue cases in Brazil

et al. 2017

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“…The previous result should be understood as a null model for our data and, thus, we would expect a very slow decay (a logarithm decay, since our system is essentially a p-3 two-dimensional one) for the spatial correlation in h i (t) assuming that the homicide dynamics is solely ruled by diffusive aspects and environmental randomness. In fact, an approximately logarithm decay for the spatial correlation was observed in some social systems (turnout rates in elections [29,30] and obesity [25]) and also for lightning activity rates [31]. Naturally, the model of the eq.…”

Section: Per Capita Homicides H(t)mentioning

confidence: 99%

Spatial correlations, clustering and percolation-like transitions in homicide crimes

Alves¹,

Lenzi²,

Mendes³

et al. 2015

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General studies of phase transitions: Percolation PACS 89.65.-s -Social and economic systemsAbstract -The spatial dynamics of criminal activities has been recently studied through statistical physics methods; however, models and results have been focused on local scales (city level) and much less is known about these patterns at larger scales such as at a country level. Here we report on a characterization of the spatial dynamics of the homicide crimes along the Brazilian territory using data from all cities (∼5000) in a period of more than thirty years. Our results show that the spatial correlation function in the per capita homicides decays exponentially with the distance between cities and that the characteristic correlation length displays an acute increasing trend in the latest years. We also investigate the formation of spatial clusters of cities via a percolation-like analysis, where clustering of cities and a phase transition-like behavior describing the size of the largest cluster as a function of a homicide threshold are observed. This transition-like behavior presents evolutive features characterized by an increasing in the homicide threshold (where the transitions occur) and by a decreasing in the transition magnitudes (length of the jumps in the cluster size). We believe that our work sheds new lights on the spatial patterns of criminal activities at large scales, which may contribute for better political decisions and resources allocation as well as opens new possibilities for modeling criminal activities by setting up fundamental empirical patterns at large scales.

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“…As a paradigm of complex systems, this research topic relies on multidisciplinary efforts and has also been addressed by physicists via methods of statistical physics. Earthquakes [1,2], geomagnetic activities [3], climate [4] and weather-related systems [5,6] are just a few examples of systems that researchers have tackled in these pages. In particular, as pointed out by Dove and Kammen [7], one of the foremost global environmental challenges is the climate change.…”

Section: Introductionmentioning

confidence: 99%

Characterization of river flow fluctuations via horizontal visibility graphs

Braga

Alves

Costa

et al. 2016

Physica A: Statistical Mechanics and its Applications

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We report on a large-scale characterization of river discharges by employing the network framework of the horizontal visibility graph. By mapping daily time series from 141 different stations of 53 Brazilian rivers into complex networks, we present an useful approach for investigating the dynamics of river flows. We verified that the degree distributions of these networks were well described by exponential functions, where the characteristic exponents are almost always larger than the value obtained for random time series. The faster-than-random decay of the degree distributions is an another evidence that the fluctuation dynamics underlying the river discharges has a longrange correlated nature. We further investigated the evolution of the river discharges by tracking the values of the characteristic exponents (of the degree distribution) and the global clustering coefficients of the networks over the years. We show that the river discharges in several stations have evolved to become more or less correlated (and displaying more or less complex internal network structures) over the years, a behavior that could be related to changes in the climate system and other man-made phenomena.

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Long-range spatial correlations and fluctuation statistics of lightning activity rates in Brazil

Cited by 3 publications

References 34 publications

Spatial patterns of dengue cases in Brazil

Spatial patterns of dengue cases in Brazil

Spatial correlations, clustering and percolation-like transitions in homicide crimes

Characterization of river flow fluctuations via horizontal visibility graphs

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