Fabio Vittorio De Blasio

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  • F V De Blasio
  • 1999
I study a lattice stochastic model of a mutating population sensitive to the influence of a fluctuating environment. The dynamics of the population stressed by linear and periodic disturbances is investigated. In agreement with previous studies of nonspatial models, I find a critical rate of change in the environmental variable beyond which the population(More)
There are strong propositions in the literature that abiotic factors override biotic drivers of diversity on time scales of the fossil record. In order to study the interaction of biotic and abiotic forces on long term changes, we devise a spatio-temporal discrete-time Markov process model of macroevolution featuring population formation, speciation,(More)
We present experimental results for the rolling of spheres on a granular bed. We use two sets of glass and steel spheres with varying diameters and a high-speed camera to follow the motion of the spheres. Despite the complex phenomena occurring during the rolling, the results show a friction coefficient nearly independent of the velocity (0.45-0.5 for glass(More)
We present a simple model of adaptive radiation in evolution based on species competition. Competition is found to promote species divergence and branching, and to dampen the net species production. In the model simulations, high taxonomic diversification and branching take place during the beginning of the radiation. The results show striking similarities(More)
Ammonoids are a group of extinct mollusks belonging to the same class of the living genus Nautilus (cephalopoda). In both Nautili and ammonoids, the (usually planospiral) shell is divided into chambers separated by septa that, during their lifetime, are filled with gas at atmospheric pressure. The intersection of septa with the external shell generates a(More)
The morphology of subaqueous landslide deposits is seldom analyzed quantitatively or at least semi-quantitatively with regard to the dynamics of the flow. However, the peculiar morphology of the deposits can reveal information on the mechanics of propagation of the mass movement and on the mechanism of emplacement. Horseshoe-shaped deposits and oriented(More)
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