There is a seasonal cycle of sexual activity for all species of birds. It is more or less pronounced according to the species, and it is primarily controlled by the external factor of light, the daily duration and intensity of which vary during -the year, the minimum amount of light being present on December 21, while the maximum is reached on June 21 in the northern hemisphere. Rowan54 was the...

This paper contributes the analysis of the persistence of innovation activities, as measured by total factor productivity (TFP) and explores its internal and external determinants stressing its path dependent characteristics. The external conditions, namely the quality of local knowledge pools and the strength of the Schumpeterian rivalry, together with the internal conditions, that is the actu...