public void delete_U(String nombre){
		
		DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();  
	    Query query = new Query("Persona");
		query.addFilter("nombre", FilterOperator.EQUAL, nombre);
		PreparedQuery pq = datastore.prepare(query);
		Entity Persona = pq.asSingleEntity();
	    datastore.delete(Persona.getKey());
	}