Avoiding non-chaotic islands requires understanding the physical origin of these regions.

Despite this, there is some doubt as to the physical origin of quantum reflection from solid surfaces.

It may appear that the description of waves is closely related to their physical origin for each specific instance of a wave process.

Impotence has its physical origins and its psychological ones.

"Eloise's physical origin," he said, "came from a painting my mother did in 1930, which is still hanging on my wall."

Its physical origin is Pleistocene though it sits atop earlier deposits of sediments.

Mutagens may be of physical, chemical or biological origin.

Furthermore, there remains much to do in order to eliminate risks to health, both of a physical and chemical origin.

Many are difficult to account for, and our guides said there are some that have no physical origin at all.

In order to explain the physical origin of these phenomena, we shall use the Ising model as a pedagogical example.