By Hugh Bronstein BUENOS AIRES (Reuters) – Argentina ends 2013 with a heat wave that has sparked protests over electricity shortages, taking another chunk out of President Cristina Fernandez's popularity as she faces a rocky final two years in power. Budding signs of flexibility in dealing with the International Monetary Fund and the Paris Club of creditor nations might eventually make Argentina safer as Fernandez eases her trademark tough stance vis-à-vis the markets. With reserves falling, inflation rising and confidence slammed by heavy-handed currency controls, Fernandez was feeling the heat before families in some of Argentina's most populated areas took to the streets last week, banging pots and pans and shouting for their electricity to be reconnected. The electricity shortages are a consequence of under investment in the country's distribution network.