-----BEGIN PRIVACY-ENHANCED MESSAGE----- Proc-Type: 2001,MIC-CLEAR Originator-Name: webmaster@www.sec.gov Originator-Key-Asymmetric: MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB MIC-Info: RSA-MD5,RSA, QAmEF1GYEmnKwfLg9vEtZuXkq8x03YUOX9G3ci28Gs+4l+0hPSq2lH9RjUEXiumI y4R17CwGtWi7BaZoe6fIsA== 0000902664-08-002182.txt : 20080610 0000902664-08-002182.hdr.sgml : 20080610 20080610133623 ACCESSION NUMBER: 0000902664-08-002182 CONFORMED SUBMISSION TYPE: SC 13G PUBLIC DOCUMENT COUNT: 1 FILED AS OF DATE: 20080610 DATE AS OF CHANGE: 20080610 SUBJECT COMPANY: COMPANY DATA: COMPANY CONFORMED NAME: Yongye Biotechnology International, Inc. CENTRAL INDEX KEY: 0001398551 STANDARD INDUSTRIAL CLASSIFICATION: AGRICULTURE CHEMICALS [2870] IRS NUMBER: 208051010 STATE OF INCORPORATION: NV FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: SC 13G SEC ACT: 1934 Act SEC FILE NUMBER: 005-84050 FILM NUMBER: 08890392 BUSINESS ADDRESS: STREET 1: 3195 UPPER LEVEL RD. #182 CITY: ROBSON STATE: A1 ZIP: VOG 1XO BUSINESS PHONE: 604-720-4393 MAIL ADDRESS: STREET 1: 3195 UPPER LEVEL RD. #182 CITY: ROBSON STATE: A1 ZIP: VOG 1XO FORMER COMPANY: FORMER CONFORMED NAME: Golden Tan, Inc DATE OF NAME CHANGE: 20070504 FILED BY: COMPANY DATA: COMPANY CONFORMED NAME: ARDSLEY ADVISORY PARTNERS CENTRAL INDEX KEY: 0000900529 IRS NUMBER: 0 STATE OF INCORPORATION: CT FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: SC 13G BUSINESS ADDRESS: STREET 1: 262 HARBOR DRIVE, 4TH FLOOR CITY: STAMFORD STATE: CT ZIP: 06902 BUSINESS PHONE: 203-564-4230 MAIL ADDRESS: STREET 1: 262 HARBOR DRIVE, 4TH FLOOR CITY: STAMFORD STATE: CT ZIP: 06902 SC 13G 1 p08-1068sc13g.txt YONGYE BIOTECHNOLOGY INTERNATIONAL, INC. SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ---------------- SCHEDULE 13G ---------------- INFORMATION STATEMENT PURSUANT TO RULES 13d-1 AND 13d-2 UNDER THE SECURITIES EXCHANGE ACT OF 1934 Yongye Biotechnology International, Inc. (NAME OF ISSUER) Common Stock, par value $0.001 per share (TITLE OF CLASS OF SECURITIES) 986063105 (CUSIP NUMBER) April 9, 2008 (Date of Event which requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [ ] Rule 13d-1(b) [x] Rule 13d-1(c) [ ] Rule 13d-1(d) (Page 1 of 15 PAGES) - ------------------ * The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). CUSIP No. 986063105 13G PAGE 2 of 15 PAGES - -------------------------------------------------------------------------------- (1) NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Ardsley Partners Fund II, L.P. - -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP ** (a) [x] (b) [ ] - -------------------------------------------------------------------------------- (3) SEC USE ONLY - -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 1,387,500 OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 1,387,500 - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,387,500 - -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ** [ ] - -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 6.49% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** PN - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 986063105 13G PAGE 3 of 15 PAGES - -------------------------------------------------------------------------------- (1) NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Ardsley Partners Institutional Fund, L.P. - -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP ** (a) [x] (b) [ ] - -------------------------------------------------------------------------------- (3) SEC USE ONLY - -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION Delaware - -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 925,000 OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 925,000 - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 925,000 - -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ** [ ] - -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 4.42% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** PN - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 986063105 13G PAGE 4 of 15 PAGES - -------------------------------------------------------------------------------- (1) NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Ardsley Offshore Fund Ltd. - -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP ** (a) [x] (b) [ ] - -------------------------------------------------------------------------------- (3) SEC USE ONLY - -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION British Virgin Islands - -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 900,000 OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 900,000 - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 900,000 - -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ** [ ] - -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 4.31% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** CO - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 986063105 13G PAGE 5 of 15 PAGES - -------------------------------------------------------------------------------- (1) NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Ardsley Advisory Partners - -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP ** (a) [x] (b) [ ] - -------------------------------------------------------------------------------- (3) SEC USE ONLY - -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION Connecticut - -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 3,248,125 OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 3,248,125 - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,248,125 - -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ** [ ] - -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 13.97% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** PN; IA - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 986063105 13G PAGE 6 of 15 PAGES - -------------------------------------------------------------------------------- (1) NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Ardsley Partners I - -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP ** (a) [x] (b) [ ] - -------------------------------------------------------------------------------- (3) SEC USE ONLY - -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION Connecticut - -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 3,212,500 OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 3,212,500 - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,212,500 - -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ** [ ] - -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 13.84% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** PN - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 986063105 13G PAGE 7 of 15 PAGES - -------------------------------------------------------------------------------- (1) NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON Philip J. Hempleman - -------------------------------------------------------------------------------- (2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP ** (a) [x] (b) [ ] - -------------------------------------------------------------------------------- (3) SEC USE ONLY - -------------------------------------------------------------------------------- (4) CITIZENSHIP OR PLACE OF ORGANIZATION United States - -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 3,248,125 OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 3,248,125 - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 3,248,125 - -------------------------------------------------------------------------------- (10) CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES ** [ ] - -------------------------------------------------------------------------------- (11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 13.97% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** IN - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT! CUSIP No. 986063105 13G PAGE 8 of 15 PAGES ITEM 1(a). NAME OF ISSUER: The name of the issuer is Yongye Biotechnology International, Inc. (the "Company"). ITEM 1(b). ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES: 6th Floor, Xue Yuan International Tower, Zhi Chun Road, Hai Dian District, Beijing, PRC ITEM 2(a). NAME OF PERSON FILING: This statement is filed by: (i) Ardsley Partners Fund II, L.P., a Delaware limited partnership ("AP II"), with respect to the shares of Common Stock, par value $0.001 per share ("Common Stock") directly owned by it; (ii) Ardsley Partners Institutional Fund, L.P., a Delaware limited partnership ("Ardsley Institutional"), with respect to the shares of Common Stock directly owned by it; (iii) Ardsley Offshore Fund Ltd., a British Virgin Islands corporation ("Ardsley Offshore"), with respect to the shares of Common Stock directly owned by it; (iv) Ardsley Advisory Partners, a New York general partnership ("Ardsley") which serves as Investment Manager of Ardsley Offshore and the Investment Adviser of AP II, Ardsley Institutional and one or more managed accounts, with respect to the shares of Common Stock directly owned by Ardsley Offshore, AP II, Ardsley Institutional, and such managed accounts; (v) Ardsley Partners I, a New York general partnership ("Ardsley Partners") which serves as General Partner of AP II and Ardsley Institutional; and (vi) Philip J. Hempleman ("Mr. Hempleman"), the Managing Partner of Ardsley and Ardsley Partners, with respect to the shares of Common Stock owned by AP II, Ardsley Institutional, Ardsley Offshore and the managed accounts. The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party. ITEM 2(b). ADDRESS OF PRINCIPAL OFFICE OR, IF NONE, RESIDENCE: The address of the business office of each of the Reporting Persons, with the exception of Ardsley Offshore, is 262 Harbor Drive, Stamford, Connecticut 06902. The address of the registered office of Ardsley Offshore is Romasco Place, Wickhams Cay 1, Roadtown Tortola, British Virgin Islands. CUSIP No. 986063105 13G PAGE 9 of 15 PAGES ITEM 2(c). CITIZENSHIP: AP II and Ardsley Institutional are Delaware limited partnerships. Ardsley Offshore is a British Virgin Islands corporation. Ardsley and Ardsley Partners are New York general partnerships. Mr. Hempleman is a United States Citizen. ITEM 2(d). TITLE OF CLASS OF SECURITIES: Common Stock, par value $0.001 per share ITEM 2(e). CUSIP NUMBER: 986063105 ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULES 13d-1(b), OR 13d-2(b), CHECK WHETHER THE PERSON FILING IS A: (a) [ ] Broker or dealer registered under Section 15 of the Act (b) [ ] Bank as defined in Section 3(a)(6) of the Act (c) [ ] Insurance Company as defined in Section 3(a)(19) of the Act (d) [ ] Investment Company registered under Section 8 of the Investment Company Act (e) [ ] Investment Adviser registered under Section 203 of the Investment Advisers Act of 1940 (f) [ ] Employee Benefit Plan, Pension Fund which is subject to the provisions of the Employee Retirement Income Security Act of 1974 or Endowment Fund; see Rule 13d- 1(b)(1)(ii)(F) (g) [ ] Parent Holding Company, in accordance with Rule 13d- 1(b)(ii)(G); see item 7 (h) [ ] Group, in accordance with Rule 13d-1(b)(1)(ii)(H) If this statement is filed pursuant to Rule 13d-1(c), check the box. [X] CUSIP No. 986063105 13G PAGE 10 of 15 PAGES ITEM 4. OWNERSHIP. A. Ardsley Partners Fund II, L.P. (a) Amount beneficially owned: 1,387,500 (b) Percent of class: 6.49%. (The percentages used herein and in the rest of Item 4 are calculated based upon the 20,000,374 shares of Common Stock issued and outstanding as of April 13, 2008, as per the Company's Current Report on Form 8-K, as filed with the Securities and Exchange Commission on April 22, 2008, and certain warrants deemed held by each of the beneficial owners in this Item 4.) (c) (i) Sole Power to vote or direct the vote: -0- (ii) Shared power to vote or direct the vote: 1,387,500 (iii) Sole power to dispose or direct the disposition: -0- (iv) Shared power to dispose or direct the disposition: 1,387,500 B. Ardsley Partners Institutional Fund, L.P. (a) Amount beneficially owned: 925,000 (b) Percent of class: 4.42% (c) (i) Sole Power to vote or direct the vote: -0- (ii) Shared power to vote or direct the vote: 925,000 (iii) Sole power to dispose or direct the disposition: -0- (iv) Shared power to dispose or direct the disposition: 925,000 C. Ardsley Offshore Fund Ltd. (a) Amount beneficially owned: 900,000 (b) Percent of class: 4.31% (c) (i) Sole Power to vote or direct the vote: -0- (ii) Shared power to vote or direct the vote: 900,000 (iii) Sole power to dispose or direct the disposition: -0- (iv) Shared power to dispose or direct the disposition: 900,000 D. Ardsley Advisory Partners (a) Amount beneficially owned: 3,248,125 (b) Percent of class: 13.97% (c) (i) Sole Power to vote or direct the vote: -0- (ii) Shared power to vote or direct the vote: 3,248,125 (iii) Sole power to dispose or direct the disposition: -0- (iv) Shared power to dispose or direct the disposition: 3,248,125 E. Ardsley Partners I (a) Amount beneficially owned: 3,212,500 (b) Percent of class: 13.84% (c) (i) Sole Power to vote or direct the vote: -0- (ii) Shared power to vote or direct the vote: 3,212,500 (iii) Sole power to dispose or direct the disposition: -0- (iv) Shared power to dispose or direct the disposition: 3,212,500 F. Philip J. Hempleman (a) Amount beneficially owned: 3,248,125 (b) Percent of class: 13.97% (c) (i) Sole Power to vote or direct the vote: -0- (ii) Shared power to vote or direct the vote: 3,248,125 (iii) Sole power to dispose or direct the disposition: -0- (iv) Shared power to dispose or direct the disposition: 3,248,125 CUSIP No. 986063105 13G PAGE 11 of 15 PAGES ITEM 5. OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS. Not applicable. ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON. Ardsley, the Investment Manager of Ardsley Offshore and the Investment Adviser of one or more managed accounts, has the power to vote and direct the disposition of the proceeds from the sale of the shares of Common Stock owned by Ardsley Offshore, and the managed accounts, and accordingly may be deemed the direct "beneficial owner" of such shares of Common Stock. Ardsley, the Investment Adviser of AP II and Ardsley Institutional, shares the power to vote and direct the disposition of the proceeds from the sale of the shares of Common Stock owned by AP II and Ardsley Institutional and, accordingly, may be deemed the direct "beneficial owner" of such shares of Common Stock. Ardsley Partners, the General Partner of AP II and Ardsley Institutional, shares the power to vote and direct the disposition of the shares of Common Stock owned by AP II and Ardsley Institutional, and, accordingly, may be deemed the direct "beneficial owner" of such shares of Common Stock. Mr. Hempleman is the Managing Partner of Ardsley and Ardsley Partners and in that capacity directs their operations and therefore may be deemed to be the indirect "beneficial owner" of the shares of Common Stock owned by Ardsley Offshore, AP II, Ardsley Institutional and the managed accounts. Mr. Hempleman disclaims beneficial ownership of all of the shares of Common Stock reported in this 13G. ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY. Not applicable. ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP. Not applicable. ITEM 9. NOTICE OF DISSOLUTION OF GROUP. Not applicable. ITEM 10. CERTIFICATION. Each of the Reporting Persons hereby makes the following certification: By signing below I certify, to the best of my knowledge and belief, the securities referred to above were acquired in the ordinary course of business, were not acquired for the purpose of and do not have the effect of changing or influencing the control of the issuer of such securities and were not acquired in connection with or as a participant in any transaction having such purposes or effect. CUSIP No. 986063105 13G PAGE 12 of 15 PAGES SIGNATURE After reasonable inquiry and to the best of their knowledge and belief, the undersigned certify that the information set forth in this statement is true, complete and correct. DATED: as of June 10, 2008 ARDSLEY PARTNERS FUND II, L.P. BY: ARDSLEY PARTNERS I, GENERAL PARTNER BY: /s/ Steve Napoli ------------------- Steve Napoli General Partner ARDSLEY PARTNERS INSTITUTIONAL FUND, L.P. BY: ARDSLEY PARTNERS I, GENERAL PARTNER BY: /s/ Steve Napoli ------------------- Steve Napoli General Partner ARDSLEY OFFSHORE FUND LTD. BY: /s/ Neil Glass ------------------- Neil Glass Director CUSIP No. 986063105 13G PAGE 13 of 15 PAGES ARDSLEY ADVISORY PARTNERS By: ARDSLEY PARTNERS I GENERAL PARTNER BY: /s/ Steve Napoli ------------------- Steve Napoli General Partner ARDSLEY PARTNERS I BY: /s/ Steve NapoliI ------------------- Steve Napoli General Partner PHILIP J. HEMPLEMAN, INDIVIDUALLY BY: /s/ STEVE NAPOLI* ------------------- Steve Napoli As attorney in fact for Philip J. Hempleman * Evidence of Power of Attorney was filed with the Schedule 13G filed on February 15, 2006 (Acc-no: 0000902664-06-000895) and is incorporated by reference into this filing. CUSIP No. 986063105 13G PAGE 14 of 15 PAGES EXHIBIT 1 JOINT FILING AGREEMENT PURSUANT TO RULE 13d-1(k)(1) The undersigned acknowledge and agree that the foregoing statement on Schedule 13G is filed on behalf of each of the undersigned and that all subsequent amendments to this statement shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing statements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him, her or it contained herein, but shall not be responsible for the completeness and accuracy of the information concerning the other entities or persons, except to the extent that he, she or it knows or has reason to believe that such information is inaccurate. Dated as of June 10, 2008 ARDSLEY PARTNERS FUND II, L.P. BY: ARDSLEY PARTNERS I, GENERAL PARTNER BY:/s/ Steve Napoli ------------------- Steve Napoli General Partner ARDSLEY PARTNERS INSTITUTIONAL FUND, L.P. BY: ARDSLEY PARTNERS I, GENERAL PARTNER BY:/s/ Steve Napoli ------------------- Steve Napoli General Partner ARDSLEY OFFSHORE FUND LTD. BY:/s/ Neil Glass ------------------- Neil Glass Director CUSIP No. 986063105 13G PAGE 15 of 15 PAGES ARDSLEY ADVISORY PARTNERS By: ARDSLEY PARTNERS I GENERAL PARTNER BY:/s/ Steve Napoli ------------------- Steve Napoli General Partner ARDSLEY PARTNERS I BY:/s/ Steve Napoli ------------------- Steve Napoli General Partner PHILIP J. HEMPLEMAN, INDIVIDUALLY BY:/s/ Steve Napoli * ------------------- Steve Napoli Attorney-in-fact for Philip J. Hempleman * Evidence of Power of Attorney was filed with the Schedule 13G filed on February 15, 2006 (Acc-no: 0000902664-06-000895) and is incorporated by reference into this filing. -----END PRIVACY-ENHANCED MESSAGE-----