Dhaka, March 22 -- Namibia's Netumbo Nandi-Ndaitwah is set to take over as head of state on Friday, joining a still relatively small circle of women in Africa to have held the top job.- Liberia: Pioneer Sirleaf -Dubbed "Africa's Iron Lady", Liberia's Ellen Johnson Sirleaf made history when she became the continent's first elected woman president in 2005.The economist, a former international civil servant and finance minister, won a second term in 2011 and the Nobel Peace Prize the same year.She stood down in 2018 at the end of her second mandate.She managed to maintain peace in the troubled west African country, but her economic record was less strong and extreme poverty persists.Before Sirleaf, Liberia was led by a woman for less than a ye...