Acuity Earnings Rise on Improved Demand  CHICAGO (Reuters) - Acuity Brands Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=AYI.N target=/stocks/quickinfo/fullquote"&gt;AYI.N&lt;/A&gt;, a maker of  lighting products and specialty chemicals, on Tuesday said  quarterly profit rose 87 percent due to improved sales, lower  operating expenses and a lower tax rate.