While it was known that the ability to form neural crest cells declines after "stage 10," the researchers were seeking the earliest conditions surrounding formation of these important stem cells.
They are of different wave-originatedtimes, wave-originated stages, and wave-crest belts, and different preferential propagation directions and effective action ranges for each stage.
它们具有不同的起波年份、起波期和波峰带，而各期波的优势传播方向和有效作用范围又有所不同。
3
The National Weather Service had predicted that the river would crest to about 19 feet above flood stage.