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Fractional diffusion equation, boundary conditions and surface effects

We investigate a system governed by a fractional diffusion equation with an integro-differential boundary condition on the surface. This condition can be connected with several processes such as adsorption and/ or desorption or chemical reactions due …

Investigating the interplay between mechanisms of anomalous diffusion via fractional Brownian walks on a comb-like structure

The comb model is a simplified description for anomalous diffusion under geometric constraints. It represents particles spreading out in a two-dimensional space where the motions in the x-direction are allowed only when the y coordinate of the …

Reaction on a solid surface supplied by an anomalous mass transfer source

The reaction process occurring on a solid surface where active sites are present is investi- gated. The phenomenon is described by a linear kinetic equation capable of accounting for memory effects in the adsorption–desorption and a first order …

Empirical analysis on the connection between power-law distributions and allometries for urban indicators

We report on the existing connection between power-law distributions and allometries. As it was first reported in Gomez-Lievano et al. (2012) for the relationship between homicides and population, when these urban indicators present asymptotic …

Universal bursty behaviour in human violent conflicts

Understanding the mechanisms and processes underlying the dynamics of collective violence is of considerable current interest. Recent studies indicated the presence of robust patterns characterizing the size and timing of violent events in human …

Fractional Diffusion Equations and Equivalent Circuits Applied to Ionic Solutions

We investigate dilute solutions of different salts (KClO3, K2SO4, and CdCl2H2O) dissolved in Milli-Q deionized water in the context of the fractional diffusion equations and equivalent circuits. The experimental results show that in the low frequency …

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

We report on a statistical analysis of the lightning activity rates in all Brazilian cities. We find out that the average of lightning activity rates exhibit a dependence on the latitude of the cities, displaying one peak around the Tropic of …

First passage time for a diffusive process under a geometric constraint

We investigate the solutions, survival probability, and first passage time for a two dimensional diffusive process subjected to the geometric constraints of a backbone structure. We consider this process governed by a fractional Fokker-Planck …

Engagement in the electoral processes: Scaling laws and the role of the political positions

| PDF We report on a statistical analysis of the engagement in the electoral processes of all Brazilian cities by considering the number of party memberships and the number of candidates for mayor and councillor. By investigating the relationships …

Time dependent solutions for a fractional Schrödinger equation with delta potentials

We investigate, for an arbitrary initial condition, the time dependent solutions for a fractional Schrödinger equation in presence of delta potentials by using the Green function approach. The solutions obtained show an anomalous spreading …