We study multiplicative and affine sequences of real numbers defined byN(j+1)=ζ(j)N(j)+η(j),where {ζ(j)} and {η(j)} are sequences of positive real numbers (in the multiplicative case η(j)=0 for all j). We investigate the conditions under which the leading digits k of {N(j)} have the...

The growth patterns of established normal and cancer cell lines, cultured in monolayer and collagen gel, have been characterized using the cluster size distribution of cellular aggregates. HN-5 (cancer) cells exhibit, either in gel or in monolayer, power-law distributions at any time in culture,...

In the present paper we consider the functional equation describing the collisionless particle velocity distribution function f(V) in the framework of probabilistic approach. The key element of the collisionless particles description is using the waiting time distribution ψ(t). The solution of...

This paper deals with scaling laws that describe transport and correlation effects in anisotropic mediums. Diffusion approximation of correlation effects is considered in a system of perpendicular random steady flows by using the Corrsin conjecture. The correlation properties of several...

We present analytical investigations of a multiplicative stochastic process that models a simple investor dynamics in a random environment. The dynamics of the investor’s budget, x(t), depends on the stochasticity of the return on investment, r(t), for which different model assumptions are...

In this work, we studied the role played by the inactive sites present on the substrate of a growing surface. In our model, one particle sticks at the surface if the site where it falls is an active site. However, we allow the deposited particle to diffuse along the surface in accordance with...

In the present paper we extend the analysis of another model recently proposed to simulate the growth of carcinoma “in situ”, which includes cell proliferation, motility and death, as well as chemotactic interactions among cells. The tumour patterns generated by two distinct growth rules are...

We present a broad, phenomenological picture of the distribution of the length of open space linear segments, l, derived from maps of 36 cities in 14 different countries. By scaling the Zipf plot of l, we obtain two master curves for a sample of cities, which are not a function of city size. We...

In this paper we perform a statistical analysis of the high-frequency returns of the Ibex35 Madrid stock exchange index. We find that its probability distribution seems to be stable over different time scales, a stylized fact observed in many different financial time series. However, an in-depth...

One of the most aggressive phenomena in biology is the growth of cancer cells. In this paper we propose a simple model to simulate the growth of carcinoma “in situ”, which includes cell proliferation, motility and death, as well as the reciprocal influence among cells. Every simulated growth...