Techs Open Down, Applied Materials Weighs  NEW YORK (Reuters) - U.S. technology stocks opened lower on  Thursday after a sales warning from Applied Materials Inc.  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=AMAT.O target=/stocks/quickinfo/fullquote"&gt;AMAT.O&lt;/A&gt;, while weekly jobless claims data met Wall Street's  expectations, leaving the Dow and S P 500 market measures  little changed.