Nonlinear social evolution and the emergence of collective action.

Organisms from microbes to humans engage in a variety of social behaviors, which affect fitness in complex, often nonlinear ways. The question of how these behaviors evolve has consequences ranging from antibiotic resistance to human origins. However, evolution with nonlinear social interactions is challenging to model mathematically, especially in combination with spatial, group, and/or kin assortment.

The Effects of Aging and Endurance Exercise on Cardiovascular Performance in Healthy Elderly: A Review of the Literature.

CV performance declines over time in healthy elderly subjects due to aging, as well as declining physical activity. Recent studies with older, often sedentary individuals, demonstrate that aerobic endurance exercise may improve several measures of CV function. Although further research is needed to characterize the CV effects of exercise, particularly in elderly women and the oldest old population, aerobic endurance exercise should be advocated in the healthy elderly.