private function loadTimezone() {
		
		if (!is_null($this->id) and (is_null($this->tzName) or is_null($this->tzOffset))) {
			
			$this->db->setQuery('SELECT timezone_name, timezone_offset FROM `sessions` WHERE id_user = ?');
			$obj = $this->db->loadObject($this->id);
			$this->tzOffset	= $obj->timezone_offset;
			$this->tzName	= $obj->timezone_name;
			
		}
		
	}