A pressing issue in biology and social sciences is to explain how cooperation emerges in a population of self-interested individuals. Theoretical models suggest that one such explanation may involve the possibility of changing one's neighborhood by removing and creating connections to others, but this hypothesis has problems when random motion is considered and lacks experimental support. To ad...

DGLAP evolution equations may be presented in a form completely analogous to the Boltzmann equation. This provides a natural proof of the positivity of the spin-dependent parton distributions, provided the initial distributions at Q0 are also positive. In addition, the evolution to Q2 < Q0 may violate positivity, providing therefore a ’time arrow’. The positivity condition is just |∆Pij(z)| ≤ P...

Using data from the Assets and Debts Survey of 1984 and the Survey of Financial Security of 1999, we document the evolution of wealth inequality in Canada between 1984 and 1999. Our main findings are as follows: 1) wealth inequality has increased between 1984 and 1999, 2) the growth in wealth inequality has been associated with substantial declines in real average and median wealth for young co...

American social scientists rarely ever use evolutionary concepts to explain behavior, despite the potential of such concepts to elucidate major social problems. I argue that this observation can be understood as the product of three influences: an ideologically narrowed political liberalism; a fear of ''Social Darwinism'' as a scientific idea, rather than a scientific apostasy; and a widely bel...

The process of urbanization takes up a lot of wetlands, profoundly changing the natural connection of surrounding river–lake systems, all the while causing serious damage to the environment of connected catchments. Urban systems and river–lake systems are not isolated and static, there is a relation between them which is constantly changing. Based on the idea of system research, the urban syste...

Most of the real social networks extracted from various data sources evolve and change their profile over time. For that reason, there is a great need to model evolution of networks in order to enable complex analyses of theirs dynamics. The model presented in the paper focuses on definition of differences between following network snapshots by means of Graph Differential Tuple.

Cooperation is a widespread natural phenomenon yet current evolutionary thinking is dominated by the paradigm of selfish competition. Recent advances in many fronts of Biology and Non-linear Physics are helping to bring cooperation to its proper place. In this contribution, the most important controversies and open research avenues in the field of social evolution are reviewed. It is argued tha...

Modeling the evolution of networks is central to our understanding of modern large communication systems, such as the World-Wide-Web, as well as economic and social networks. The research on social and economic networks is truly interdisciplinary and the number of modeling strategies and concepts is enormous. In this survey we present some modeling approaches, covering classical random graph mo...

in this paper the sociological approach of janet wolff and john thompson is used to identify and interpret the relationship between the evolution of persian carpet and its social context. the social context includes socio-economic, ideologican and political conditions surronding this evolution. to study persian carpet from the pazric rug from its initiation to the present time, based on numorou...