We explore sustainable paths out of a debt trap with a highly stylized two-sector differential equations model for the stocks of money in Government and Society. The model fits the data for the U.S. between 1981 and 2012 with a coefficient of correlation of 0.996. The solutions provide detailed...

A first order linear differential equation is used to describe the dynamics of an investment fund that promises more than it can deliver, also known as a Ponzi scheme. The model is based on a promised, unrealistic interest rate; on the actual, realized nominal interest rate; on the rate at which...

Multiregional Demography: Principles, Methods and Extensions. by Andrei Rogers. John Wiley & Sons. 1994. 236 pp. Incl. IBM PC Disk with SPACE Computer Program.

It is generally thought that for sake of consistency men and women must have the same average number of lifetime partners. However, this is not the case in general. When men have younger partners, women enter sexual relationships more quickly than men and have a higher number of lifetime...

Probabilities of transmission and numbers of secondary cases are given for an infection which is transmitted sexually by individuals engaged in multiple partnerships with specified durations and timings. The results applied to the human immunodeficiency virus (HIV) hinge on a function which...