Exhibit 24.2

                               Power of Attorney


     The undersigned, Arun Sarin, hereby authorizes and appoints Ellen B. Alben
and Tammy D. Halstead, and each of them, with full power of substitution and
resubstitution and full power to act without the other, as his true and lawful
attorney-in-fact and agent to act in his name, place and stead and to execute in
the name and on behalf of him, individually and in each capacity stated below
and to file, any and all amendments to this Registration Statement, including
any and all post-effective amendments and amendments thereto and any
registration statement relating to the same offering as this Registration
Statement that is to be effective upon filing pursuant to Rule 462(b) under the
Securities Act of 1933, as amended, and to file the same, with all exhibits
thereto, and other documents in connection therewith, with the Securities and
Exchange Commission, granting unto said attorneys-in-fact and agents, and each
of them, full power and authority to do and perform each and every act and
thing, ratifying and confirming all that said attorneys-in-fact and agents or
any of them, or her or their substitute or substitutes, may lawfully do or cause
to be done by virtue thereof.

                                             /s/ Arun Sarin
                                             ---------------------------
                                             Arun Sarin