Exhibit 3.55


                          CERTIFICATE OF INCORPORATION

                                       OF

                             CMI OF ARLINGTON, INC.

            The undersigned, a natural person, for the purpose of organizing a
corporation for conducting the business and promoting the purposes hereinafter
stated, under the provisions and subject to the requirements of the laws of the
State of Delaware (particularly Chapter 1, Title 8 of the Delaware Code and the
acts amendatory thereof and supplemental thereto, and known, identified, and
referred to as the "General Corporation Law of the State of Delaware"), hereby
certifies that:

            FIRST: The name of the corporation (hereinafter called the
"Corporation") is CMI OF ARLINGTON, INC.

            SECOND: The address, including street, number, city, and county, of
the registered office of the Corporation in the State of Delaware is 1013 Centre
Road, City of Wilmington 19805, County of New Castle, and the name of the
registered agent of the Corporation in the State of Delaware at such address is
Corporation Service Company.

            THIRD: The purpose of the Corporation shall be to promote any lawful
act or activity for which corporations may be organized under the General
Corporation Law of the State of Delaware.

            FOURTH: The total number of shares of stock which the Corporation
shall have authority to issue is 100. The par value of each of such shares is
$.05. All such shares are of one class and are shares of Common Stock.

            FIFTH: The name and the mailing address of the incorporator are as
follows:



                   NAME                    MAILING ADDRESS
                   ----                    ---------------
                                        
                   Lydia Lim               6464 Canoga Ave.
                                           Woodland Hills, CA  91367-2407


            SIXTH: The Corporation is to have perpetual existence.

            SEVENTH: Whenever a compromise or arrangement is proposed between
this Corporation and its creditors or any class of them and/or between this
Corporation and its stockholders or any class of them, any court of equitable
jurisdiction within the State of Delaware may, on the application in a summary
way of this Corporation or of any creditor or stockholder thereof or on the
application of any receiver or receivers appointed for this Corporation under
Section 291 of Title 8 of the Delaware Code or on the application of trustees in
dissolution or of any receiver or receivers appointed for this Corporation under
Section 279 of Title 8 of

the Delaware Code order a meeting of the creditors or class of creditors, and/or
of the stockholders or class of stockholders of this Corporation, as the case
may be, to be summoned in such manner as the said court directs. If a majority
in number representing three fourths in value of the creditors or class of
creditors, and/or of the stockholders or class of stockholders of this
Corporation, as the case may be, agree to any compromise or arrangement and to
any reorganization of this Corporation as consequence of such compromise or
arrangement, the said compromise or arrangement and the said reorganization
shall, if sanctioned by the court to which the said application has been made,
be binding on all the creditors or class of creditors, and/or on all the
stockholders or class of stockholders, of this Corporation, as the case may be,
and also on this Corporation.

            EIGHTH: For the management of the business and for the conduct of
the affairs of the Corporation, and in further definition, limitation, and
regulation of the powers of the Corporation and of its directors and of its
stockholders or any class thereof, as the case may be, it is further provided:

                  1. The management of the business and the conduct of the
            affairs of the Corporation shall be vested in its Board of
            Directors. The number of directors which shall constitute the whole
            Board of Directors shall be fixed by, or in the manner provided in,
            the Bylaws. No election of directors need be by written ballot.

                  2. After the original or other Bylaws of the Corporation have
            been adopted, amended, or repealed, as the case may be, in
            accordance with the provisions of Section 109 of the General
            Corporation Law of the State of Delaware, and, after the Corporation
            has received any payment for any of its stock, the power to adopt,
            amend, or repeal the Bylaws of the Corporation may be exercised by
            the Board of Directors of the Corporation; provided, however, that
            any provision for the classification of directors of the Corporation
            for staggered terms pursuant to the provisions of subsection (d) of
            Section 141 of the General Corporation Law of the State of Delaware
            shall be set forth in an initial Bylaw or in a Bylaw adopted by the
            stockholders entitled to vote of the Corporation unless provisions
            for such classification shall be set forth in the certificate of
            incorporation.

                  3. Whenever the Corporation shall be authorized to issue only
            one class of stock, each outstanding share shall entitle the holder
            thereof to notice of, and the right to vote at, any meeting of the
            stockholders. Whenever the Corporation shall be authorized to issue
            more than one class of stock, no outstanding share of any class of
            stock which is denied voting power under the provisions of the
            certificate of incorporation shall entitle the holder thereof to the
            right to vote at any meeting of stockholders except as the
            provisions of paragraph (2) of subsection (p) of Section 242 of the


                                       2

            General Corporation Law of the State of Delaware shall otherwise
            require; provided, that no share of any such class which is
            otherwise denied voting power shall entitle the holder thereof to
            vote upon the increase or decrease in the number of authorized
            shares of said class.

            NINTH: The personal liability of the directors of the Corporation is
hereby eliminated to the fullest extent permitted by the provisions of paragraph
(7) of subsection (b) of Section 102 of the General Corporation Law of the State
of Delaware, as the same may be amended and supplemented.

            TENTH: The Corporation shall, to the fullest extent permitted by the
provisions of Section 145 of the General Corporation Law of the State of
Delaware, as the same may be amended and supplemented, indemnify any and all
persons whom it shall have power to indemnify under said section from and
against any and all of the expenses, liabilities, or other matters referred to
in or covered by said section, and the indemnification provided for herein shall
not be deemed exclusive of any other rights to which those indemnified may be
entitled under any Bylaw, agreement, vote of stockholders or disinterested
directors or otherwise, both as to action in his official capacity and as to
action in another capacity while holding such office, and shall continue as to a
person who has ceased to be a director, officer, employee, or agent and shall
inure to the benefit of the heirs, executors, and administrators of such a
person.

            ELEVENTH: From time to time any of the provisions of this
certificate of incorporation may be amended, altered, or repealed, and other
provisions authorized by the laws of the State of Delaware at the time in force
may be added or inserted in the manner and at the time prescribed by said laws,
and all rights at any time conferred upon the stockholders of the Corporation by
this certificate of incorporation are granted subject to the provisions of this
Article ELEVENTH.

Signed on February 17, 1998



/s/ Lydia Lim
- ---------------------------
Lydia Lim
Incorporator




                                       3

                            CERTIFICATE OF AMENDMENT

                                       OF

                          CERTIFICATE OF INCORPORATION

                                       OF

                             CMI OF ARLINGTON, INC.

            CMI of Arlington, Inc., a corporation organized and existing under
and by virtue of the General Corporation Law of the State of Delaware, does
hereby certify:

            1. The name of the corporation is CMI of Arlington, Inc.
(hereinafter called the "Corporation");

            2. The Certificate of Incorporation of the Corporation is hereby
amended by deleting Article First thereof and substituting the following
therefor:

                  "The name of the Corporation (hereinafter called the
            "Corporation") is IMI of Arlington, Inc."

            3. The amendment of the certificate of incorporation herein
certified has been duly adopted in accordance with the provisions of Sections
228 and 242 of the General Corporation Law of the State of Delaware.

Executed on this 5th day of March, 1998.

                                          /s/ Nanci K. Carr
                                          ---------------------------
                                          Nanci K. Carr
                                          Assistant Secretary

             CERTIFICATE OF CHANGE OF LOCATION OF REGISTERED OFFICE
                             AND OF REGISTERED AGENT
                             IMI OF ARLINGTON, INC.



It is hereby certified that:

            1. The name of the corporation (hereinafter called the
"Corporation") is IMI of Arlington, Inc.

            2. The registered office of the Corporation within the State of
Delaware is hereby changed to 9 East Loockerman Street, City of Dover 19901,
County of Kent.

            3. The registered agent of the Corporation within the State of
Delaware is hereby changed to National Registered Agents, Inc., the business
office of which is identical with the registered office of the corporation as
hereby changed.

            4. The Corporation has authorized the changes hereinbefore set forth
by resolution of its Board of Directors.

Signed on May 23, 2000

                                          /s/ Wayne K. Baldwin
                                          -------------------------------------
                                          Wayne K. Baldwin, Secretary & General
                                          Counsel

             CERTIFICATE OF CHANGE OF LOCATION OF REGISTERED OFFICE
                             AND OF REGISTERED AGENT

                             IMI OF ARLINGTON, INC.



It is hereby certified that:

            1. The name of the corporation (hereinafter called the
"corporation") is:

                             IMI OF ARLINGTON, INC.

            2. The registered office of the corporation within the State of
Delaware is hereby changed to 2711 Centerville Road, Suite 400, City of
Wilmington 19808, County of New Castle.

            3. The registered agent of the corporation within the State of
Delaware is hereby changed to Corporation Service Company, the business office
of which is identical with the registered office of the corporation as hereby
changed.

            4. The corporation has authorized the changes hereinbefore set forth
by resolution of its Board of Directors.

Signed on May 16, 2003

                                          /s/ Robin Smith Hoke
                                          -------------------------------------
                                          Name: Robin Smith Hoke
                                          Title: Vice President




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