Purine N-oxides. LVIII. N-Hydroxypurine analogs. N-Hydroxypyrrolo [2,3-d] pyrimidines

Abstract

Compd pHXmax(= X ir3) 2, R = H 3.0 279 (7.4), 244 (7.6), 216 (9.5) 6.37 ± 0.002 10 300 (7.0), 258 (7.2) ~12 2, R = Me 3.6 285 (7.7), 249 (9.2), 216 (12.5) 6.41 ± 0.02 9 304 (8.8), 262 (14.0) 12.42 ± 0.05 14

Determining the Instantaneous Direction of Motion from Optical Flow Generated by a Curvilinearly Moving Observer

“…Nakayama and Loomis (1974) and Fennema and Thompson (1979) studied how discontinuities in the "retinal" velocity field could be used for segmentation purposes. Clocksin (1980), Gibson et al (1955), and Lee (1974) studied how the optical flow generated by an observer translating in a stationary world provides information about (local) surface orientation. Koenderink and van Doorn (1976), LonguetHiggins and Prazdny (1980), and Prazdny (1980and Prazdny ( , 1981 studied the ( extraction of surface orientation, (relative) depth and motion from optical flow generated by an arbitrary curvilinear motion.…”