Learn More
The role of African savannahs in the evolution of early hominins has been debated for nearly a century. Resolution of this issue has been hindered by difficulty in quantifying the fraction of woody cover in the fossil record. Here we show that the fraction of woody cover in tropical ecosystems can be quantified using stable carbon isotopes in soils.(More)
OBJECTIVE Transcranial magnetic stimulation (TMS) uses a medical device that applies magnetic pulses noninvasively to the cortex of the brain to depolarize neurons. We tested its safety and efficacy in young persons with a diagnosis of attention-deficit/hyperactivity disorder (ADHD). METHODS Transcranial magnetic stimulation was applied to the right(More)
Two major problems for a theory of coordinated movement are considered: The context-conditioned variability in the terminal variables of the motor apparatus, and the management of the large number of degrees of freedom that the motor apparatus attains. One approach to these problems argues that, in general, the free-variables of the motor apparatus are not(More)
  • 1