Vortex re-capturing and kinematics in human underwater undulatory swimming

To maximize swimming speed athletes copy fish undulatory swimming during the underwater period after start and turn. The anatomical limitations may lead to deviations and may enforce compensating strategies. This has been investigated by analyzing the kinematics of two national female swimmers while swimming in a still water pool. Additionally, the flow around and behind the swimmers was measured with the aid of time-resolved particle image velocimetry (TR-2D-PIV). As compared to fish, the swimmers used undulatory waves characterized by much higher Strouhal numbers but very similar amplitude distributions along the body and Froude efficiencies. Vortices generated in the region of strongly flexing joints are suitable to be used pedally to enhance propulsion (vortex re-capturing). Complementing studies using numerical and technical modeling will help us to probe the efficiency of observed mechanisms and further improvements of the human strategy.     

The influence of monetary reward and punishment on psychological, physiological, behavioral and performance aspects of a golf putting task

The primary purpose of the present study was to examine kinematic characteristics and force control during a golf-putting task under a pressure condition. The secondary purpose was to provide an exploratory investigation of the relationship between changes in behavior (kinematics and force control) and performance on the one hand, and psychological (attention and affect) and physiological (arousal level) changes on the other hand. Twenty male novices performed 150 acquisition trials, followed by 10 test trials during a pressure condition induced by performance-contingent distracters: a cash reward or punishment. A three-dimensional motion analysis revealed that, during the pressure test, angular displacements of rotational movements at the horizontal plane and movement time of the arms and club during the backswing and downswing phases all decreased, while acceleration of the elbows during the downswing phase increased. Mean performance indices in all participants’ were unchanged in spite of the kinematic changes under the pressure condition. Multiple regression analyses indicated that the decrement in performance, as well as increased variability of movement time and speed, were more likely to increase when participants shifted their attention to movements. Furthermore, changes in heart rate and negative affect were related to both the increase in movement acceleration and a decrease in grip force. These findings suggest that performance and behavioral changes during golf-putting under pressure can be associated with attentional changes, along with the influences of physiological-emotional responses.     

Processing time predictions of current models of perception in the classic additive factors paradigm

This article explores the consequences for factorial additivity in a Sternberg [(1969). The discovery of processing stages: Extensions of donders method In: W.G. Koster (Ed.), Attention and performance II, Acta Psychologica, 30, 276-315] additive-factors paradigm of the assumptions adopted by models of perception that relate the representation of a stimulus to decision time. Three example models, signal detection theory with the latency-distance hypothesis, stochastic general recognition theory, and a random walk model of exemplar classification, are interrogated to determine what type of interaction they predict factors will yield in a hypothetical factorial (choice) reaction time experiment in which the ‘empirical’ factors’ effects are manifest as parameter changes. All frameworks make the critical assumption that decision time depends on the perceptual representation of the stimulus as well as the architecture. As a consequence, nonadditivity of factors thought to affect different “stages” in the classical approach emerges within the current modeling approach. The nature of this influence is revealed through analytic investigations and simulation. Earlier empirical findings of failures of selective influence that have defied adequate explanation are reinterpreted in light of the present findings.     

The Incompleteness of ‘Punishment as Fair Play’: A Response to Dagger

Richard Dagger (in this issue) provides perhaps the most persuasive version of a ‘fair play’ theory of criminal punishment, grounded in an attractive liberal republican political theory. But, I argue, his version of the theory still faces serious objections: that its explanation of why some central mala in se are properly criminalised is still distorting, despite his appeal to the burdens of ‘general compliance’; and that it cannot adequately explain (as it should explain) the differential seriousness and wrongfulness of different kinds of crime.

材料的呈现方式对大学生分类活动影响的研究

以60名视力、智力均正常的大学生为被试,采用维度特征互不相同的三套图片材料和三种材料呈现方式,以被试分类的结果和解释的理由为依据,用一维特征分类、整体相似性分类、两阶段策略分类和其他分类等作为因变量指标,采用不完全被试内设计进行实验。用SPSS 8．0 for windows对实验结果进行处理。结果：在A方式下,被试倾向于按材料的一维特征分类;在B方式下,被试倾向于按材料的整体相似性分类;在C方式下,被试倾向于按两阶段策略分类。     

Stress state mediation between environmental variables and performance: The case of noise and vigilance

Effects of environmental variables on performance may be mediated by individual stress states. In this study the effects of jet-aircraft engine noise and signal salience on vigilance performance and self-reported stress state were examined. One hundred and ninety-two (96 female and 96 male) participants were randomly assigned to four experimental conditions consisting of 48 participants each resulting from the factorial combination of signal salience (high and low salience signals) and noise (95 dBA intermittent aircraft noise or quiet). Performance metrics and self-reported stress state (Task Engagement, Distress, and Worry) were collected. Performance in the noise conditions was significantly better than in the quiet conditions. Performance in the high salience conditions was significantly better than the low salience conditions. Noise elevated Task Engagement and low signal salience elevated Distress. Moreover, structural equation model analyses were used to examine stress state mediation between the experimental variables and performance. These analyses indicated Engagement mediates between noise and vigilance performance.     

Effects of luminance change in preview search: Offsets and onsets can be concurrently prioritized but not in isolation

Two experiments are performed to investigate how luminance change contributes to prioritized selection of new over old elements. Experiment 1 demonstrates that observers prioritize items that undergo a luminance change irrespective of the direction of that change. Experiment 2 shows that foreknowledge concerning the direction of luminance change signaling the target does not allow observers to prioritize the selection of luminance onsets over offsets and vice versa. The results suggest that prioritized selection of new over old elements is mediated by a general mechanism that is sensitive to luminance change, irrespective of its direction.     

治疼必需知痛

疼痛是人体可感知所有伤害性刺激中最难以忍受的恶性刺激,医学范畴下的疼痛是指组织损伤的前提下产生的＂躯体的不愉快的疼感觉＂加上＂与之相匹配的痛苦情感体验＂两方面内容。长期以来我们的医疗行为＂过多关注组织损伤对疼的调控、忽视了痛苦体验的人文关怀＂制约了我们服务层次。新的生物医学模式下诊疗工作强调细化疼痛分类、躯体与心理并重,以专科诊疗思路指导临床,提高医务人员对病痛的理解、引导供需匹配式的人性医疗服务是时代发展务实之举。     

不育症临床治疗中的人文关怀

目前临床对抑郁症的诊断仍普遍存在概念不清的现象,甚至抑郁症的诊断有逐渐被泛化的倾向,本文从抑郁症研究历史的角度,通过对抑郁症的概念及分类历史进行回顾,以期能廓清抑郁症相关的一些概念,从而为进一步统一标准、细化抑郁症的研究提供一些启示。