This paper tests the occurrence of rational bubbles in the exchange rate of Brazil, Russia, India, China and South Africa (the ‘BRICS' countries group) against the US dollar. We consider bubbles of the periodically recurring variety, and assume that the fundamental value follows a modified PPP...

We test the assumption that the relation between sexual activity and wage is nonlinear, considering that the impact of sex on productivity and therefore on wage occurs during a certain interval of times which one cannot perceive if discrimination is not done. In other words, we must use...