Umaru Yar'Adua has been sworn in as Nigeria's new president.

The inauguration of Alhaji Yar'Adua marks the first time in Nigeria's history that one civilian leader has taken over from another but the election in April was described by local and foreign observers as "not credible".

What are your views on Mr Yar’Adua’s appointment? Will his leadership transform Nigeria? What challenges does the country face? Has outgoing President Olusegun Obasanjo left Nigeria a strengthened democracy?