Depression may be challenging to assess in a patient with dementia. In patients with AD, the presence of depression may range from 6% to 30%, depending on the diagnostic criteria employed (Cummings et al., 1995). The prevalence and course of depression in dementia are controversial, due to several confounding factors.
Astronauts use space shuttles(trasport people and equipment), Space probes (robotic exploration, Spacecrafts (trasport crew, equipment, and other technologies).
NASA engineers have finished testing a new ion-propulsion system for earth-orbiting and interplanetary spacecraft. The system is more powerful and fuel-efficient than its predecessors, enabling it to travel farther than ever before. Ion propulsion works by electrically charging, or ionizing, a gas using power from solar panels and emitting the ionized gas to propel the spacecraft in the opposite direction.