Bronislaw Komorowski has taken the oath of office as Poland's new President, vowing to build national unity in a ceremony boycotted by the man he beat for the top job. Komorowski, a moderate conservative from the ruling Civic Platform, defeated Jaroslaw Kaczynski in the July 4 run-off. The election was triggered by the death of Mr Kaczynski's twin brother, president Lech Kaczynski, in a plane crash in April.