This election season Minnesota Public Radio is analyzing some of the television spots the U-S Senate candidates and their surrogates are using to influence voters. More than a dozen have aired since May...but only a few of those have come from the candidates themselves. Today Minnesota Public Radio's Bill Wareham looks at ads produced by the Boschwitz and Wellstone campaigns: Astute television viewers who read the "paid for" announcements at the end of political ads will notice ads produced by a candidate's own campaign have a softer tone than those coming from the National Republican Senatorial Committee and the Minnesota DFL. Unlike the NRSC ads that call Paul Wellstone an 'ult