Fig. 3: Schematic representation of the institution growth model.
From: The emergence of heterogeneous scaling in research institutions
a At time t a new researcher is hired, modeled as extracting a ball with uniform probability with replacement from an urn, U (black arrow). The ball color represents an institution. Hiring a researcher will always add ρ new balls of the same color to the urn in the next timestep (reinforcement). Hiring the first researcher at an institution (picking a ball color that has never been picked before), triggers ν + 1 new colors to enter the urn, increasing the likelihood of more institutions to hire their first researcher (triggering). b Researchers within each institution (dash-dotted boxes) have both internal collaborators (darker solid lines) and external collaborators (gray lines). Once a researcher is hired, they choose one random internal and one random external collaborator (solid arrows). New collaborations (dashed arrows) are formed independently with probability pA, if hired by institution A, and pB if hired by institution B. These new connections form triangles.
