Transcranial Doppler (TCD), first described in 1982 [1], is a noninvasive ultrasound (US) study that involves the use of a low-frequency (â¤2 MHz) transducer probe to insonate the basal cerebral arteries through relatively thin bone windows.
Details. as.character and is.character are generic: you can write methods to handle specific classes of objects, see InternalMethods. Further, for as.character the default method calls as.vector, so dispatch is first on methods for as.character and then for methods for as.vector.
A static character, in this vocabulary, is one that does not undergo important change in the course of the story, remaining essentially the same at the end as he or she was at the beginning. A dynamic character, in contrast, is one that does undergo an important change in the course of the story.