protected function _prepareDataForSave(Mage_Core_Model_Abstract $object)
    {
        $currentTime = Varien_Date::now();
        if ((!$object->getId() || $object->isObjectNew()) && !$object->getCreatedAt()) {
            $object->setCreatedAt($currentTime);
        }

        $object->setUpdatedAt($currentTime);
        $data = parent::_prepareDataForSave($object);
        return $data;
    }