A hotly disputed study of Proposition 77's likely effects concluded Monday that California's redistricting initiative would produce an additional 11 competitive seats in the Legislature and 10 in Congress. The Rose Institute study, likely to become a centerpiece of debate over Proposition 77, was immediately touted by supporters of the initiative as a boost to their campaign and by opponents as one-sided propaganda. The 36-page study, using computer modeling, predicted that passage of Proposition 77 in the Nov. 8 election would boost the number of competitive seats in California politics to: * Ten in the U.S. House of Representatives, compared...