/**
  * Método construtor
  */
 public function __construct()
 {
     $oSessao = Zend_Session::namespaceGet('sessao');
     if (isset($oSessao['acl'])) {
         $this->_auth = Zend_Auth::getInstance();
         self::$_acl = $oSessao['acl'];
     }
 }