native variable for one level above $document_root ?

[George]

At the nginx vhost level, is there a native nginx value similar to
$document_root for one directory level above $document_root ?

for example if $document_root = /home/username/public or
/home/username2/public

is there a variable I can reference at nginx vhost level that references
/home/username or /home/username2 ?

thanks

George

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,257127,257127#msg-257127