We analyze the variability in the x-ray lightcurves of the black hole candidate Cygnus X-1 by linear and nonlinear time series analysis methods. While a linear model describes the overall second order properties of the observed data well, surrogate data analysis reveals a significant deviation from linearity. We discuss the relation between shot noise models usually applied to analyze these dat...

Inferring species interactions from co-occurrence data is one of the most controversial tasks in community ecology. One difficulty is that a single pairwise interaction can ripple through an ecological network and produce surprising indirect consequences. For example, the negative correlation between two competing species can be reversed in the presence of a third species that outcompetes both ...

recent developments in nanostructured products draw considerable attention to ultrafine grained materials. these materials are normally manufactured by different severe plastic deformation (spd) methods. in the present study, analytical models and finite element method (fem) are used to calculate strain imposed to a specimen that was deformed by equal channel angular pressing (ecap). in additio...

It has been recently suggested that models of deformed special relativity, based on a deformed Poincak group, could account for the missing mass problem, due to the nonadditivity of energy for large systems predicted by these models. We show that this is not correct and that, in fact, these models predict just the opposite effect. Recently, different explanations have been proposed to account f...

We study the structure of the phase space of generic models of deformed special relativity which gives rise to a definition of velocity consistent with the deformed Lorentz symmetry. In this way we can also determine the laws of transformation of spacetime coordinates.

We study the structure of the phase space of generic models of deformed special relativity which gives rise to a definition of velocity consistent with the deformed Lorentz symmetry. In this way we can also determine the laws of transformation of spacetime coordinates.