Form 10-Q (Mark One) þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended December 31, 2018 ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 U. S. SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 _____________________________________________ (Address of principal executive offices) (623) 445-9500 (Registrant's telephone number, including area code) Indicate by check mark whether the registr ...