Dengue is caused by 4 genetically related but antigenically different viruses, and although it is uncertain where DENV evolved, maintenance of all 4 serotypes in enzootic cycles in Africa suggests that a progenitor virus most likely originated in Africa (1 ).
First conceived as a therapeutic response that was limited in time and ended with a withdrawal from methadone [ 5], OSTM progressively evolved towards maintenance treatments that are considered necessary over the long-term (methadone maintenance treatments, MMT) [ 6].
As predicted from the U-shaped dose response curve characteristics of essential metals, mechanisms designed to prevent deficiency or overdose toxicity have likely evolved for maintenance of homeostasis (Slikker et al. 2004).
Furthermore, this work is based on the strong belief that evolving largely efficient maintenance workforce schemes significantly enhance performance of work-systems.
Eventually, though, as the Woods mustered the talents of their friends, Clingstone and its maintenance evolved into a communal lifestyle, and ultimately a kind of religion.
As infrastructure systems evolve, their design, maintenance, and optimal performance require mature tools from system reliability theory, as well as principles to handle emerging system features, such as controllability.
To overcome these issues, eukaryotic cells evolved the telomere maintenance system, the almost universal mechanism used to protect chromosome ends [4].
Death from intrinsic causes is optimized to the level of extrinsic mortality through evolved limitations on maintenance efforts (Kirkwood 1977; Kirkwood and Rose 1991).
Species with low investment in early reproduction are thus expected to be able to evolve more efficient maintenance and repair mechanisms, allowing for a longer potential life span (intrinsic longevity).
Likewise, the model can explain the universal age-dependent pattern of cancer incidence as rate-limited primarily by microenvironmental effects that suppress or promote somatic evolution in an age-dependent manner, as dictated by differential investment in tissue maintenance evolved for particular species.
