Bind log entries ending with plus or minus

Tue Oct 17 04:56:04 UTC 2006

What do the '+' and '-' signify at the end of my log entries? I've 
recently updated my bind version and I see these magical new symbols...

16-Oct-2006 17:02:43.929 queries: info: client A.B.C.D#55615: query: 
my.com IN A +
16-Oct-2006 17:02:47.165 queries: info: client A.B.C.D#65046: query: 
my.com IN AXFR -
16-Oct-2006 17:02:47.165 xfer-out: info: client A.B.C.D#65046: transfer 
of 'my.com/IN': AXFR started
16-Oct-2006 17:02:47.179 xfer-out: info: client A.B.C.D#65046: transfer 
of 'my.com/IN': AXFR ended