INFORMATION TO USERS The most advanced technology has been used to photo- graph and reproduce this manuscript from the microfilm master.UMI films the text directly from the original or copy submitted.Thus,some thesis and dissertation copies are in typewriter face,while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted.Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough,substandard margins,and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages,these will be noted.Also,if unauthorized copyright material had to be removed,a note will indicate the deletion. Oversize materials (e.g.,maps,drawings,charts)are re- produced by sectioning the original,beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps.Each original is also photographed in one exposure and is included in reduced form at the back of the book.These are also available as one exposure on a standard 35mm slide or as a 17"x 23" black and white photographic print for an additional charge. Photographs included in the original manuscript have been reproduced xerographically in this copy.Higher quality 6"x 9"black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge.Contact UMI directly to order. UMI University Microfilms International A Bell Howell Information Company 300 North Zeeb Road,Ann Arbor,MI 48106-1346 USA 313/761-4700800/521-0600INFORMATION TO USERS The most advanced technology has been used to photo￾graph and reproduce this manuscript from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are re￾produced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. These are also available as one exposure on a standard 35mm slide or as a 17" x 23" black and white photographic print for an additional charge. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. University Microfilms International A Bell & Howell Information Company 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 313/761-4700 800/521-0600