- print_r: documentation ( source)
- date_default_timezone_set: documentation ( source)
<?php
date_default_timezone_set('America/Los_Angeles');
$now = new Datetime("2013-04-09 23:45:15","UTC");
$lv = new Datetime("2013-04-09 23:44:21");
$interval = $now->diff($lv,true);
print_r($lv);
print_r($interval);