464 research outputs found
The Dark Side of Service Leaders
The rapid growth of service economies calls for effective service leaders. According to Po Chung (Co-founder of DHL International and Chairman Emeritus of DHL Express (Hong Kong) Limited), effective service leaders should possess competence, character and care (3Cs). In addition, a lack of these qualities constitutes the dark side of service leadership. In this chapter, the dark side of service leadership is examined at three levels. First, “viruses” in leadership are examined through the lens of the Service Leadership Theory. Second, attributes of the dark side of leadership with particular reference to problems in competence, character and care based on the existing scientific literature are outlined. Finally, the dark side of service leadership with reference to Confucian virtues is addressed
The mechanism of word crowding
AbstractWord reading speed in peripheral vision is slower when words are in close proximity of other words (Chung, 2004). This word crowding effect could arise as a consequence of interaction of low-level letter features between words, or the interaction between high-level holistic representations of words. We evaluated these two hypotheses by examining how word crowding changes for five configurations of flanking words: the control condition – flanking words were oriented upright; scrambled – letters in each flanking word were scrambled in order; horizontal-flip – each flanking word was the left–right mirror-image of the original; letter-flip – each letter of the flanking word was the left–right mirror-image of the original; and vertical-flip – each flanking word was the up–down mirror-image of the original. The low-level letter feature interaction hypothesis predicts similar word crowding effect for all the different flanker configurations, while the high-level holistic representation hypothesis predicts less word crowding effect for all the alternative flanker conditions, compared with the control condition. We found that oral reading speed for words flanked above and below by other words, measured at 10° eccentricity in the nasal field, showed the same dependence on the vertical separation between the target and its flanking words, for the various flanker configurations. The result was also similar when we rotated the flanking words by 90° to disrupt the periodic vertical pattern, which presumably is the main structure in words. The remarkably similar word crowding effect irrespective of the flanker configurations suggests that word crowding arises as a consequence of interactions of low-level letter features
Attenuation of perceived motion smear during vergence and pursuit tracking
AbstractWhen the eyes move, the images of stationary objects sweep across the retina. Despite this motion of the retinal image and the substantial integration of visual signals across time, physically stationary objects typically do not appear to be smeared during eye movements. Previous studies indicated that the extent of perceived motion smear is smaller when a stationary target is presented during pursuit or saccadic eye movements than when comparable motion of the retinal image occurs during steady fixation. In this study, we compared the extent of perceived motion smear for a stationary target during smooth pursuit and vergence eye movements with that for a physically moving target during fixation. For a target duration of 100 ms or longer, perceived motion smear is substantially less when the motion of the retinal image results from vergence or pursuit eye movements than when it results from the motion of a target during fixation. The reduced extent of perceived motion smear during eye movements compared to fixation cannot be accounted for by different spatio-temporal interactions between visual targets or by unequal attention to the moving test spot under these two types of conditions. We attribute the highly similar attenuation of perceived smear during vergence and pursuit to a comparable action of the extra-retinal signals for disjunctive and conjugate eye movements
Learning to identify contrast-defined letters in peripheral vision
AbstractPerformance for identifying luminance-defined letters in peripheral vision improves with training. The purpose of the present study was to examine whether performance for identifying contrast-defined letters also improves with training in peripheral vision, and whether any improvement transfers to luminance-defined letters. Eight observers were trained to identify contrast-defined letters presented singly at 10° eccentricity in the inferior visual field. Before and after training, we measured observers’ thresholds for identifying luminance-defined and contrast-defined letters, embedded within a field of white luminance noise (maximum luminance contrast=0, 0.25, and 0.5), at the same eccentric location. Each training session consisted of 10 blocks (100 trials per block) of identifying contrast-defined letters at a background noise contrast of 0.5. Letters (x-height=4.2°) were the 26 lowercase letters of the Times-Roman alphabet. Luminance-defined letters were generated by introducing a luminance difference between the stimulus letter and its mid-gray background. The background noise covered both the letter and its background. Contrast-defined letters were generated by introducing a differential noise contrast between the group of pixels that made up the stimulus letter and the group of pixels that made up the background. Following training, observers showed a significant reduction in threshold for identifying contrast-defined letters (p<0.0001). Averaged across observers and background noise contrasts, the reduction was 25.8%, with the greatest reduction (32%) occurring at the trained background noise contrast. There was virtually no transfer of improvement to luminance-defined letters, or to an untrained letter size (2× original), or an untrained retinal location (10° superior field). In contrast, learning transferred completely to the untrained contralateral eye. Our results show that training improves performance for identifying contrast-defined letters in peripheral vision. This perceptual learning effect seems to be stimulus-specific, as it shows no transfer to the identification of luminance-defined letters. The complete interocular transfer, and the retinotopic (retinal location) and size specificity of the learning effect are consistent with the properties of neurons in early visual area V2
Color and motion: which is the tortoise and which is the hare?
AbstractRecent psychophysical studies have been interpreted to indicate that the perception of motion temporally either lags or is synchronous with the perception of color. These results appear to be at odds with neurophysiological data, which show that the average response-onset latency is shorter in the cortical areas responsible for motion (e.g., MT and MST) than for color processing (e.g., V4). The purpose of this study was to compare the perceptual asynchrony between motion and color on two psychophysical tasks. In the color correspondence task, observers indicated the predominant color of an 18°×18° field of colored dots when they moved in a specific direction. On each trial, the dots periodically changed color from red to green and moved cyclically at 15, 30 or 60 deg/s in two directions separated by 180°, 135°, 90° or 45°. In the temporal order judgment task, observers indicated whether a change in color occurred before or after a change in motion, within a single cycle of the moving-dot stimulus. In the color correspondence task, we found that the perceptual asynchrony between color and motion depends on the difference in directions within the motion cycle, but does not depend on the dot velocity. In the temporal order judgment task, the perceptual asynchrony is substantially shorter than for the color correspondence task, and does not depend on the change in motion direction or the dot velocity. These findings suggest that it is inappropriate to interpret previous psychophysical results as evidence that motion perception generally lags color perception. We discuss our data in the context of a “two-stage sustained-transient” functional model for the processing of various perceptual attributes
Erratum to “Development of a training protocol to improve reading performance in peripheral vision” [Vision Res. 50 (1) (2010) 36–45]
Level structure of 153Dy and the competition between collective and few-particle excitation modes in Dy Nuclei
The 153Dy level structure has been studied through the 124Sn(34S, 5n) reaction. The low-spin collective character of 153Dy gives way to single particle yrast configurations at I > 41 2; an I= 47 2 isomer at 5591 ke V shows the single particle character (and overall oblate shape) to be well established at that spin. Nuclear shape charges in Dy nuclei are discussed
Aligned νi13 2 bands coupled to different shapes in 186Hg
The structure of 186Hg has been studied through the 156Gd(34S, 4n) reaction. Three bands with even spin and parity are observed; two of them are established up to high spin and are found to cross with little interaction at I= 16+. Cranked shell model calculations suggest that these two bands can be associated with a decoupled νi13 2 pair based on a prolate and on an oblate or triaxial shape, respectively
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