Many unicellular organisms live in multicellular communities that rely on cooperation between cells. However, cooperative traits are vulnerable to exploitation by non-cooperators (cheaters). We expand our understanding of the molecular mechanisms that allow multicellular systems to remain robust in the face of cheating by dissecting the dynamic regulation of cooperative rhamnolipids required fo...

Traditionally, downside risk aversion is the study of the placement of a pure risk (a secondary risk) on either the upside or the downside of a primary two-state risk. When the decision maker prefers to have the secondary risk placed on the upside rather than the downside of the primary lottery, he is said to display downside risk aversion. The literature on the intensity of downside risk avers...

Higher-order risk attitudes include risk aversion, prudence, and temperance. This paper analyzes the eff ects of such preferences on medical test and treatment decisions, represented either by test and treatment thresholds or – if the test characteristics are endogenous – by the optimal cutoff value for testing. For a risk-averse decision maker, treatment is a risk reducing strategy since it pr...

The rst section recalls the de nitions of risk apportionment. Section 2 introduces notation and section 3 de nes ambiguity apportionment. Section 4 gives results for secondorder expected utility and multiplier preferences and in section 5, a way to adapt the de nitions to ambiguity models with non-expected utility under risk is proposed. Finally, section 6 presents simple models of precautionar...