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.
Dealing with focus is important enough that I will take the next four months to go through each method, discussing how that sort of focused character generation works. Until then, you can play the game of figuring out what method of character creation you use for your characters, and what order you complete the steps.