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                                                                    EXHIBIT 23.1


                         CONSENT OF INDEPENDENT AUDITORS


             We consent to the use of our report included herein and to the
references to our firm included in the Annual Report on Form 11-K for the NCI
401(k) Profit Sharing Plan.

             We also consent to the incorporation by reference in the
Registration Statements on Form S-8 (No. 333-14957 and No. 33-52078) pertaining
to the NCI 401(k) Profit Sharing Plan of our report dated June 22, 2001 with
respect to the statements of net assets available for benefits of the NCI 401(k)
Profit Sharing Plan as of December 31, 2000 and 1999, and the related statement
of changes in net assets available for benefits for the year ended December 31,
2000, included in this Annual Report on Form 11-K.



                                        /s/ KOLKHORST & KOLKHORST
                                        Kolkhorst & Kolkhorst




Houston, Texas
June 25, 2001