These mathematical methods go beyond analyzing science; they apply to a number of other problems in areas ranging from biology and medicine to technology and finance. For example, one can use these new mathematical tools to address questions such as: How has air traffic changed around the world? How do social contacts change when illnesses develop and spread? How has the flow of capital changed in the global economy? How has the structure of scientific research changed over the past decade? In the study concerned, published in the journal PloS One, the researchers illustrated the power of their methods by addressing the last of these questions.
“We wanted to map changes in science over the past decade. To do so, we started with more than 35 million citations between the articles in over 7000 scientific journals. This network of citations represents the flow of information between researchers in the world and the results show that significant changes have occurred in the life sciences. Neuroscience has gone from being an interdisciplinary research area to being a scientific discipline in its own right, ranking alongside physics, chemistry, economics, law, molecular biology and medicine,” says Martin Rosvall, Assistant Professor at the Department of Physics, Umeå University.
The key to understanding complex and integrated structures such as the scholarly research literature is to think of them as networks. In a network, the components of the system are represented by nodes and the interactions between the components consist of links between the nodes. “People have done a great deal of work on how to find the important features of a network at one specific point in time. But we have not had ways of looking at how these networks change over time,” explains Rosvall.
“Detecting structural changes in large networks is a problem that consists of two parts,” explains Carl Bergstrom, professor at the Department of Biology, University of Washington. “First, we identify statistically significant changes in the structure of a network, and second we provide an intuitive way to visualize these changes.” These new tools will be useful in understanding a world permeated with change. As the pre-Socratic philosopher Heraclitus wrote over 2500 years ago: “Everything flows, nothing stands still.”