JOINT FILING AGREEMENT

     In accordance with Rule  13d-1(k)(1)  under the Securities Act of 1934, the
undersigned  hereby  agree to the joint  filing with each other of the  attached
statement on Schedule 13G and to all  amendments to such statement and that such
statement  and all  amendments  to such  statement  is made on behalf of each of
them.

     IN WITNESS WHEREOF,  the undersigned  hereby execute this Agreement on July
10, 2007.




                                       NATIONWIDE SA CAPITAL TRUST



                                    By:/s/Gerald J. Holland
                                       Name:    Gerald J. Holland
                                       Title:   Senior Vice President





                                       NATIONWIDE FUND ADVISORS



                                    By:/s/Gerald J. Holland
                                       Name:    Gerald J. Holland
                                       Title:   Senior Vice President