This is an extended version of an essay with the same title that I wrote for the workshop Algebraic Process Calculi: The First Twenty Five Years and Beyond, held in Bertinoro, Italy in the first week of August 2005.

In the k-set agreement problem, each process proposes a value and has to decide a value in such a way that a decided value is a proposed value and at most k different values are decided. This problem can easily be solved in synchronous systems or in asynchronous systems prone to t process crashes when t < k. In contrast, it has been shown that k-set agreement cannot be solved in asynchronous sy...

Bacterial cell-to-cell communication (‘quorum sensing’) is mediated by structurally diverse, small diffusible signal molecules which regulate gene expression as a function of cell population density. Many different Gramnegative animal, plant and fish pathogens employ Nacylhomoserine lactones (AHLs) as quorum sensing signal molecules which control diverse physiological processes including biolum...

Deoxynivalenol (DON) is one of several mycotoxins produced by certain Fusarium species that frequently infect corn, wheat, oats, barley, rice, and other grains in the field or during storage. It is a toxic byproduct of Fusarium head blight in grains and feeds. Potential human exposure to DON may occur from ingestion of products made from contaminated grains. It has been detected in buckwheat, p...