Repeated Exposure to Forward Support-Surface Perturbation During Overground Walking Alters Upper-Body Kinematics and Step Parameters

Locomotion requires both proactive and reactive control strategies to maintain balance. The current study aimed to: (i) ascertain upper body postural responses following first exposure to a forward (slip) support-surface perturbation; (ii) investigate effects of repeated perturbation exposure; (iii) establish relationships between arms and other response components (trunk; center of mass control). Young adults (N = 11) completed 14 walking trials on a robotic platform; six elicited a slip response. Kinematic analyses were focused on extrapolated center of mass position (xCoM), bilateral upper- and forearm elevation velocity, trunk angular velocity, and step parameters. Results demonstrated that postural responses evoked in the first slip exposure were the largest in magnitude (e.g., reduced backward stability, altered reactive stepping, etc.) and preceded by anticipatory anterior adjustments of xCoM. In relation to the perturbed leg, the large contra- and ipsilateral arm responses observed (in first exposure) were characteristically asymmetric and scaled to the degree of peak trunk extension. With repeated exposure, xCoM anticipatory adjustments were altered and in turn, reduced posterior xCoM motion occurred following a slip (changes plateaued at second exposure). The few components of the slip response that persisted across multiple exposures did so at a lesser magnitude (e.g., step length and arms).     

项安世卦变说新探

卦变说是理解项安世易说的关键,其卦变说接续了李挺之的相关识见,分反对卦与不反对八卦。反对卦皆自消息卦来,不反对卦皆自坎离来。以坎离作为主变之卦,既是对汉代易学重视坎离传统的接续,又融合了丹道思想,更是对当时理学家体用思想的认同与接纳,这使得项氏卦变说既具有深厚的传统积淀又有鲜明的时代认同。项氏卦变说的理论动机是从易象本身开显易道之变易,以弥补程颐仅从义理一面揭示易道变易之不足。     

The conscious experience of color constancy and neural responses to subliminal deviations – A behavioral and EEG/ERP oddball study

IntroductionColor constancy, a property of conscious color experience, maintains object color appearance across illuminant changes. We investigated the neural correlates of subliminal vs. conscious stimulus deviations of color constancy manipulations.MethodsBehavioral and Oddball EEG/ERP experiments were conducted (n = 20). Psychophysical illuminant variation discrimination thresholds were first estimated, to establish individual perceptual awareness ranges, allowing for simulation of natural daylight spectral and spatial variations on colored surfaces, at different ambiguity levels.ResultsBehavioral results validated illuminant choice. ERPs showed a significant modulation of posterior P1 component specifically for the subliminal global uniform deviation condition, respecting color constancy. Neural correlates of conscious percepts were identified at posterior N2-P3 latencies, parietal (P3b) and frontal regions.ConclusionsWe identified an early subliminal correlate of low-level illuminant change, which reflects automatic unconscious detection of global color constancy deviations. Its suppression under conscious perception is probably due to top-down suppression according to prediction error models.     

Support and compliance with 20 mph speed limits in Great Britain

There are a number of challenges relating to both the support of and compliance with speed limits. The introduction of 20 mph limits in Great Britain is no exception: the recent rise in the deployment of these limits in urban settings has created a need to understand these issues in more depth. This paper reports a study undertaken by the authors that used a population wide survey of GB drivers to explore how support and compliance were interlinked. Whilst as expected many supporters said they would comply with the limits, and many opponents might not comply, more surprisingly it was also found that some supporters claimed not to comply, while some opponents of 20 mph limits were compliers. Explanations included the strong likelihood of strong moral adherence to not breaking laws amongst opponent–compliers, and self-enhancement bias amongst supporter–non-compliers. This paper explores the incidence of these effects and their implications in detail.