One possible explanation is that as the system has matured, the inefficiencies have become more important, dragging down the returns on new spending.

This gives temporary protection against some infections, until the child's own immune system has matured.

"As the system matures, you learn that some of that can become destructive after a while," he added.

Only the resident oligodendrocyte precursor cells seem to keep this ability after the nervous system matures.

As the nervous system matures, muscles can move in response to stimuli.

By this point, around 1987, the system had matured into a useful tool, and a number of developers started using it on major projects.

In mid-1989, however, it was unclear whether the political system in Bolivia had matured enough to allow for compromise.

It was not until 1974 that the system had matured technically.

As the system matures and development costs decrease, earnings begin to rise along with cash flow.

Polymicrogyria typically forms while the embryo's central nervous system is maturing.