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Eight-five patients with a total of 103 resin-bonded bridges placed by practitioners at the University of Minnesota School of Dentistry between 1982 and 1989 were recalled for a clinical evaluation of their restorations. Tissue condition, patient satisfaction, bridge failures by location and by sex of patient, and average length of service for both successful and failed bridges were recorded. After an average service of 3.25 years, 12.6% of the fixed partial dentures had debonded. Debondings occurred most frequently in the mandibular arch. Failures occurred more frequently in men than in women, and prostheses with more than two retainers had twice the probability for problems. [ABSTRACT FROM AUTHOR]

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. We derive a mathematical condition for natural selection with synergistic interactions among any number of individuals. This result applies to populations with arbitrary (but fixed) spatial or network structure, group subdivision, and/or mating patterns. In this condition, nonlinear fitness effects are ascribed to collectives, and weighted by a new measure of collective relatedness. For weak selection, this condition can be systematically evaluated by computing branch lengths of ancestral trees. We apply this condition to pairwise games between diploid relatives, and to dilemmas of collective help or harm among siblings and on spatial networks. Our work provides a rigorous basis for extending the notion of "actor", in the study of social evolution, from individuals to collectives., (© The Author(s) 2024. Published by Oxford University Press on behalf of National Academy of Sciences.)

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.