NAPERVILLE - Nicor Inc., parent of Nicor Gas, posted third-quarter net income of $13.6 million, or 30 cents per share, compared to $1.3 million, or 3 cents per share, for the same period a year ago. Operating revenue was $325.6 million, compared to $440.3 million a year ago. Earnings for the third quarter reflected an improved operating income in the company's gas distribution and other energy-related businesses; and higher corporate operating results, partially offset by lower operating income in the company's shipping business. The third quarter comparisons also reflect a lower effective income tax rate partially offset by lower pretax equity investment income, the company said.