The recent price movements of the world's most widely-watched soybean, corn and wheat futures contracts have called to mind once again the question of what is the role of the U.S. market in determining world grain and oilseed values and whether those values move up or down.CME July soybeans are roaring higher. Our last look at mid-session showed they were up more than $0.60 since Tuesday's close and trading above $15.30. New crop November soybeans were up more than $0.45 to near $12.45. That is pretty hefty price movement in less than two days of trade. In the same time frame, CME July corn has gained a mere $0.04, but it was trading above $5.00 less than 10 days ago. Currently, the new crop December corn price is virtually unchanged since...