EXHIBIT 99.906CERT

Certification Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002

In connection with the attached report of the registrant on Form N-CSR to be
filed with the Securities and Exchange Commission (the "Report"), each of the
undersigned officers of the registrant does hereby certify, to the best of such
officer's knowledge, that:

1. The Report fully complies with the requirements of Section 13(a) or
   Section 15(d) of the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly represents, in all material
   respects, the financial condition and results of operations of the registrant
   as of, and for, the periods presented in the Report.

Date:  August 3, 2006


PATRICK P. COYNE
________________________________
By:      Patrick P. Coyne
Title:   President and Chief Executive Officer


MICHAEL P. BISHOF
________________________________
By:      Michael P. Bishof
Title:   Chief Financial Officer

A signed original of this written statement required by Section 906 of the
Sarbanes-Oxley Act, or other document authenticating, acknowledging, or
otherwise adopting the signatures that appear in typed form within the
electronic version of this written statement required by Section 906, has been
provided to the registrant and will be retained by the registrant and furnished
to the SEC or its staff upon request.