Hygiene and biosecurity: the language and politics of risk in an era of emerging infectious diseases

Infectious diseases, such as methicillin-resistant Staphylococcus aureus and avian influenza, have recently been high on the agenda of policy makers and the public. Although hygiene and biosecurity are preferred options for disease management, policy makers have become increasingly aware of the critical role that communication assumes in protecting people during outbreaks and epidemics. This article makes the case for a language-based approach to understanding the public perception of disease. Health language research carried out by the authors, based on metaphor analysis and corpus linguistics, has shown that concepts of journeys, pathways, thresholds, boundaries and barriers have emerged as principal framing devices used by stakeholders to advocate a hygiene based risk and disease management. These framings provide a common ground for debate, but lead to quite different perceptions and practices. This in turn might be a barrier to global disease management in a modern world.

A Tutorial on the Universality and Expressiveness of Fold

In functional programming, fold is a standard operator that encapsulates a simple pattern of recursion for processing lists. This article is a tutorial on two key aspects of the fold operator for lists. First of all, we emphasize the use of the universal property of fold both as a proof principle that avoids the need for inductive proofs, and as a definition principle that guides the transformation of recursive functions into definitions using fold. Secondly, we show that even though the pattern of recursion encapsulated by fold is simple, in a language with tuples and functions as first-class values the fold operator has greater expressive power than might first be expected.