Biomedical subjects
Publications and source records attributed to E McSorley.
An efficient regioselective method for the direct arylation of 2-furaldehyde to provide a range of pi-diverse 5-aryl-2-formylfuran derivatives is described. The method employs functionalized aryl halides and a catalytic amount of palladium(II) chloride under relatively mild conditions.
The accuracy of saccade localisation during visual search was examined for a search target defined by the single features of orientation or depth or by a conjunction of the two features. Subjects were required to move their eyes to the target which appeared in one of eight possible locations, arranged circularly around fixation, with non-targets filling the remaining seven positions. Search for a target defined by a single feature resulted in approximately 70% correct first saccades in both cases, while search for the conjunction target resulted in only 40% correct first saccades. Furthermore, averaged latency for conjunction search was longer than for simple search. Nevertheless, some subjects showed a remarkably good ability to locate a conjunction target with a single saccade of short latency. An analysis of first saccades in terms of their speed and accuracy indicates that the target selection is not preceded by a covert scanning of the display but rather is a result of parallel processing of the visual information provided. We also relate our study to the study of conjunction search reported by Nakayama and Siverman [Nakayama, K., & Silverman, G.H. (1986). Serial and parallel processing of visual feature conjunctions. Nature, 320, 264-265.].
Three pairs of experiments were conducted to investigate the importance of spatial-frequency-processing delays imposed by the visual system on the efficacy of their subsequent integration. In the first pair of experiments filtered versions of a natural image were found to be easily discriminable from the full-bandwidth image. These images were then placed into triplets and presented sequentially. Subjects were required to detect the presence of a full-bandwidth target image within the sequence. As with previous results a low-to-high progression of spatial-frequency information did increase the number of errors of full-bandwidth-image detection within the triplets where it was not present. However, this was not found across all conditions and was suggested to be due to the increased discriminability of the constituent images which form the image triplets. The second experiment was a repetition of the first with more confusable component images. Again the weak order effect on target detection was found. It was suggested that this may be due to the nature of the stimulus used. The third pair of experiments repeated the design of the first pair of experiments but with Gabor patches which provide localised spatial-frequency information. It was found that a low-to-high progression of spatial frequencies resulted in more false detections of the target. The results are interpreted as supporting an integration mechanism which operates with greater efficacy when the presentation of spatial-frequency information mirrors that naturally imposed by the neural delays involved in the processing of spatial frequencies.