MRI of a knee. MRIs employ powerful magnets which produce a strong magnetic field that forces protons in the body to align with that field. When a radiofrequency current is then pulsed through the patient, the protons are stimulated, and spin out of equilibrium, straining against the pull of the magnetic field.
Noun. 1. aestivation - (zoology) cessation or slowing of activity during the summer; especially slowing of metabolism in some animals during a hot or dry period. estivation. zoological science, zoology-the branch of biology that studies animals.
Estivation is when animals slow their activity for the hot, dry summer months. During a period of estivation, many reptiles go underground where it's cooler. Estivation is very similar to hibernation, when some mammals spend the winter moving very little and sleeping a lot, in order to save energy. During estivation, animals become still and their breathing slows â but it occurs during the hottest months of the year. Reptiles, amphibians, and molluscs are most likely to go through estivation. The Latin root word is aestus, or heat..