I didn't apply to Duke, but I emailed UMD to find out what is going on. I have been told that the adcom started reviewing applications only couple of weeks ago, and have not reached any decision regarding shortlisting of candidates. Here is the verbatim:
"The finalists will be notified for an interview-type process a bit later in the Spring. The incoming class will be very small, as you are aware of. But the committee just began reviewing applications a couple of weeks ago, so we have not selected finalists yet."
Wait is really painful, but what else can we do except waiting, right?
Hang in there.