Dollar heads for worst week since July; yen underpinned by BOJ

By Rocky Swift and Lucy Raitano TOKYO/LONDON (Reuters) -The dollar headed for its worst week since late July on Friday as the U.S. government shutdown increased uncertainty, while the yen pulled back from this week's highs as traders mulled the Bank of Japan's next move ahead of a ruling party leadership election this weekend. The dollar index, which measures the greenback against a basket of