Chicago-area businesses were a lot less gloomy in April, according to the Chicago Business Barometer released Thursday. The Chicago index rose to 40.1% from 31.4 in March. It was the largest one-month increase in the index since 1983. The index shows business activity in the Chicago area declined in April for the seventh straight month but at a much slower pace. Readings under 50 indicate most firms said business was getting worse. Production, new orders and employment all improved.