We extend an earlier model of protein evolution on a rugged landscape (Macken, C.A. & Perelson, A.S., {\it Proc. Natl. Acad. Sci. USA} {\bf 86,} 6191 (1989)) to the case in which the landscape exhibits a variable degree of correlation (i.e., smoothness). Correlation is introduced by assuming...

We develop a probability based model that suggests a novel explanation for the enormous diversity of the lymphocyte repertoire in the immune system. Taking into account the fraction of the repertoire that is expected to be rendered tolerant because of potential self reactivity, we calculate...

We use mathematical models to describe the interaction of the immune system with the human immunodeficiency virus (HIV). Our model includes T-lymphocytes and macrophages, cells which can be infected with the virus. Using our model we compare the efficacy of AZT treatments given at different...

In an electoral framework of unidimensional two-candidate spatial competition with probabilistic voting, special interest groups present candidates with schedules that give the level of campaign contribution they will make for each feasible candidate policy location. Candidates, motivated by the...