Decision of the appellate court ordering the continuation of provisional enforcement of a judicial judgment relating to a contract containing an arbitration clause. Argument that the Brazilian Arbitration Act would not be applicable to contracts entered into before its entry into force. Stay of the effects of the decision of the court of origin, on account of the likelihood of dismissal of the case by reason of the arbitration clause and the economic harm arising from the continuation of provisional enforcement of the judgment (Itaipu case):