Nasdaq Ends Up, Dow Slips  NEW YORK (Reuters) - The tech-driven Nasdaq Composite Index  got a 1 percent boost on Thursday on gains in the semiconductor  sector, but the blue-chip Dow ended down slightly after  Caterpillar Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=CAT.N target=/stocks/quickinfo/fullquote"&gt;CAT.N&lt;/A&gt; warned about higher steel prices and  other costs.