This paper analyses productivity growth and the nature of techni- cal change in a sample of Portuguese hydroelectric generating plants over the period 2001 to 2004. In a ¯rst step, we employ the Luen- berger productivity indicator to estimate and decompose productivity change. The results paint...

This study analyses the persistence in the international monthly arrivals to the Azores Islands using a model based on fractional integration and seasonal autoregressions. The estimated fractional differencing parameter gives an indication of the long run evolution of the series. We use both...