arXiv subjects

Y. Bar-Yam

Publications and source records attributed to Y. Bar-Yam.

5 recordsLinked to original sources

arXiv2018

Comparison of the roughness scaling of the surface topography of Earth and Venus

We report the scaling behavior of the Earth and Venus over a wider range of length scales than reported by previous researchers. All landscapes (not only mountains) together follow a consistent scaling behavior, demonstrating a crossover between highly correlated (smooth) behavior at short length scales (with a scaling exponent $α$=1) and self-affine behavior at long length scales ($α$=0.4). The self-affine behavior at long scales is achieved on Earth above 10 km and on Venus above 50 km.

cond-mat.stat-mech↗

arXiv2013

Mean Field Approximation to a Spatial Host-Pathogen Model

We study the mean field approximation to a simple spatial host-pathogen model that has been shown to display interesting evolutionary properties. We show that previous derivations of the mean field equations for this model are actually only low-density approximations to the true mean field limit. We derive the correct equations and the corresponding equations including pair-correlations. The process of invasion by a mutant type of pathogen is also discussed. [This article was published as Physical Review E 67, 047102 (2003). Errata for the published version are corrected here and explicitly listed at the end of this document.]

q-bio.PE↗

arXiv2004

Spectral Analysis and the Dynamic Response of Complex Networks

The eigenvalues and eigenvectors of the connectivity matrix of complex networks contain information about its topology and its collective behavior. In particular, the spectral density $ρ(λ)$ of this matrix reveals important network characteristics: random networks follow Wigner's semicircular law whereas scale-free networks exhibit a triangular distribution. In this paper we show that the spectral density of hierarchical networks follow a very different pattern, which can be used as a fingerprint of modularity. Of particular importance is the value $ρ(0)$, related to the homeostatic response of the network: it is maximum for random and scale free networks but very small for hierarchical modular networks. It is also large for an actual biological protein-protein interaction network, demonstrating that the current leading model for such networks is not adequate.

nlin.AO↗

arXiv2000

Formalizing the gene centered view of evolution

A historical dispute in the conceptual underpinnings of evolution is the validity of the gene centered view of evolution. \cite{dawkins,lewontin} We transcend this debate by formalizing the gene centered view as a dynamic version of the mean field approximation. This establishes the conditions under which it is applicable and when it is not. In particular, it breaks down for trait divergence which corresponds to symmetry breaking in evolving populations.

physics.bio-ph↗

arXiv1999

The Mesostructure of Polymer Collapse and Fractal Smoothing

We investigate the internal structure of a polymer during collapse from an expanded coil to a compact globule. Collapse is more probable in local regions of high curvature, so a smoothing of the fractal polymer structure occurs that proceeds systematically from the shortest to the longest length scales. A proposed universal scaling relationship is tested by comparison with Monte Carlo simulations. We speculate that the universal form applies to various fractal systems with local processes that promote smoothness over time. The results complement earlier work showing that on the macroscale polymer collapse proceeds by driven diffusion of the polymer ends.

cond-mat.soft↗