miss.chain <- function(x,time) {
#
# return a chain like x with NA's inserted whereever there is
# a break in time. This function is used primarily to prepare x for
# input into the functions count and gcount, which compute transition
# matricies.
#
n<-(x)
brk <- c(((time[2:n]-time[1:(n-1)]) > 1),F)
k <- sum(brk)
if (k == 0) {
  temp <- x
  } else {
  brks <- (1:n)[brk]
  temp <- x[1:brks[1]]
  if (k > 1) {
    for (i in 2:k) {
      temp <- c(temp,NA,x[(brks[i-1]+1):brks[i]])
      }
    }
  temp <- c(temp,NA,x[(brks[k]+1):n])
  }
temp
}