Dow Slips, Nasdaq, S P 500 Flat  NEW YORK (Reuters) - The blue-chip Dow average declined  slightly, while the Nasdaq and the S P 500 were little changed  on Tuesday as investors waited for an expected quarter-point  hike in U.S. interest rates and results from technology  bellwether Cisco Systems Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=CSCO.O target=/stocks/quickinfo/fullquote"&gt;CSCO.O&lt;/A&gt;.