We present and analyze a model for the cross-regulation of the Th1 and Th2 helper cell subsets during an immune response by the regulatory cytokines interferon-$\gamma$ (IFN-$\gamma$) and interleukin-10 (IL-10). IFN-$\gamma$, secreted by Th1 cells, can inhibit the proliferation of Th2 cells....

I consider the research university from a complex adaptive systems perspective, and offer some modest proposals for the university of the future-a student-based complex adaptive learning community in which both feedback and transdisciplinary problem-oriented Centers play central roles. <p> <p> To...</p></p>

In recent studies, new measures of complexity for nonlinear systems have been proposed based on probabilistic grounds, as the LMC measure (Phys. Lett. A 209 (1995) 321). All these measures share an intuitive consideration: complexity seems to emerge in nature close to instability points, as for...

This paper introduces a simple two-dimensional map exhibiting several generic properties reported in excitable systems. The elementary dynamic that is analogous to that of neural elements, is analyzed using phase-plane methods. Bifurcations from non-autonomous to autonomous, and from periodic to...

Since the classic work of Feyerabend and Kuhn, the role of social factors in the scientific enterprise has been a major concern in the philosophy and history of science. In particular, the presence of social factors such as the desire for prestige or pressures to conform to accepted ideas, have...

Inefficient delays in trades can sometimes be observed after the arrival of important public news. This paper explains these phenomena with a model in which agents defer trades in the fear that they may be taken advantaged of by better informed trading partners. Under certain conditions, delay...

In the framework of the median voter theorem, an ideologically driven candidate can fully alter policy when running against a vote-maximizing oponent. When turnout is allowed to depend on the relative positioning of the ideal points of the candidates relative to the voter, this result need not...

General equilibrium theory in economics defines the relative prices for goods and services, but does not fix the absolute values of prices. We present a theory of money in which the value of money is a time dependent "strategic variable," to be chosen by the individual agents. The idea is...