By MarketsFarm WINNIPEG, Dec. 17 (MarketsFarm) The Canadian dollar was slightly weaker on Tuesday, dipping just below 76 U.S. cents. At 8:30 CST, the Canadian dollar was at US$0.7592 or C$1.3171, which compares with Monday’s North American close of US$0.7609 or C$1.3142. Stocks were mixed as the shine has worn off of the trade agreement