By John S. McClenahen In terms of inflation-adjusted GDP growth, the first half of 2004 will outperform the second half, believe the economists at UBS Investment Research, New York. They foresee a seasonally adjusted annual rate of 4.5% during the first half and 3.3% rate during the second half of this year. They expect GDP in the current quarter, which ends March 31, to come in at a 5% rate, the second quarter to be 4%, the third quarter 3.3% and the final quarter of 2004 to repeat the third-quarter rate of 3.3%. How about interest rates? UBS' economists expect inflation to have crept up enough that the Federal Reserve's Open Market Committee will raise the federal funds rate target, now 1%, before year-end.