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Clustering and spreading of behavior and opinion in social networks. Lazaros Gallos Levich Institute, City College of New York Hernan A. Makse - Shlomo Havlin. Clustering and spreading of behavior in social networks. Lazaros Gallos Levich Institute, City College of New York
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Clustering and spreading of behavior and opinion in social networks LazarosGallos LevichInstitute, City College of New York Hernan A. Makse - ShlomoHavlin
Clustering and spreading of behavior in social networks LazarosGallos LevichInstitute, City College of New York Hernan A. Makse - ShlomoHavlin
BMI and obesity The Body Mass Index (BMI) is a standard measure of human body fat BMI>30 is generally accepted as the obesity threshold
What we know on obesity ‘spreading’ • Genetics • Peer pressure(Christakis and Fowler, NEJM, 2007) • Spatial clustering
Our approach • The physics of clustering is challenging • Study obesity as a percolation process • Use scaling analysis • More properties
Time evolution of obesity clusters County obesity %
Largest clusters County obesity %
Neighbors influence (after Christakis, Fowler)
Scaling theory of Growth • Standard theory of Gibrat assumes random growth • Scaling concepts introduced by the H.E. Stanley group(Stanley, Nature, 1996) for the growth of companies • Extended to more properties (e.g. cities) Growth rate: Spatial correlations:
Limits High correlations: No correlations: b =0, g =0 b =0.5 , g =2 (in 2d)
Spatial correlations (constant in time) g =0.5 Obesity • g =1.0 • Population
Time evolution of g Weak correlations Strong correlations
Phase diagram g /d 1/4 1/2 1 Weak correlations Strong correlations
Conclusions • Strong spatial correlationsin obesity spreading • Obesity clusters grow faster than the population growth • Scaling analysis quantifies the degree of spatial correlations • Exponents are related Three main universality classes based on spatial correlations