public function execute($request)
 {
     $this->setLayout(false);
     sfConfig::set('sf_web_debug', false);
     sfConfig::set('sf_debug', false);
     if ($this->getRequest()->isXmlHttpRequest()) {
         $this->getResponse()->setHttpHeader('Content-Type', 'application/json; charset=utf-8');
     }
     $nationalityId = $request->getParameter('id');
     $service = new NationalityService();
     $nationality = $service->getNationalityById($nationalityId);
     return $this->renderText(json_encode($nationality->toArray()));
 }