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.
The study of a character requires an analysis of its relations with all of the other characters in the work. The individual status of a character is defined through the network of oppositions (proairetic, pragmatic, linguistic, proxemic) that it forms with the other characters.