By CaixaBank research team, in Barcelona | The upswing exceeded expectations with a first quarter GDP that grew by 1.0% quarter-on-quarter and 2.6% year-on-year. This momentarily places Japan at the head of advanced economies in terms of growth. However, the forecast for the whole of 2012 hardly reaches 2.5%, as the composition of the national accounts raises doubts regarding the sustainability of the upswing. Unusually, the growth of the first…