IMPACT — There have been a lot of stories in recent days about the impact of the nuclear talks on oil prices. Don’t believe them. Yes, the price of a barrel of OPEC oil went up and down before, during and after the talks. But the shift was very small. The daily chart above marks the price last Wednesday, the day before the talks began, and the price on Monday, the day after the talks were adjourned. The difference between those two days was 47 cents and the difference between the high and low point of that four-day period was $1.07.