Sirius Names Karmazin CEO, Shares Jump  LOS ANGELES (Reuters) - Sirius Satellite Radio Inc.  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=SIRI.O target=/stocks/quickinfo/fullquote"&gt;SIRI.O&lt;/A&gt; on Thursday named former Viacom Inc. President Mel  Karmazin as its chief executive, in the latest migration of a  mainstream radio heavyweight to the fledgling satellite  industry.