One- or Two-Legged Standing

To highlight the capacity of one- and two-legged standing protocols when assessing postural behavior induced by a rigid ankle orthosis, 14 healthy individuals stood upright barefoot and wore either an elastic stocking on the preferred leg or a rigid orthosis with or without additional taping in one- or two-legged (TL) conditions. Traditional center-of-pressure (CP) measures were evaluated for the total two-feet resultant CP and under the feet (plantar CP). Focusing on the plantar CP displacements under the leg fitted with the various orthoses demonstrated particular postural behaviors for traditional parameters with main effects along the mediolateral axis. Only the TL protocol showed the limiting effects of the rigid shells on the inversion-eversion movements in healthy individuals.     

Aging of running shoes and its effect on mechanical and biomechanical variables: implications for runners

Abstract

This study investigates the effect of running shoes’ aging on mechanical and biomechanical parameters as a function of midsole materials (viscous, intermediate, elastic) and ground inclination. To this aim, heel area of the shoe (under calcaneal tuberosity) was first mechanically aged at realistic frequency and impact magnitudes based on a 660 km training plan. Stiffness (ST) and viscosity were then measured on both aged and matching new shoes, and repercussions on biomechanical variables (joint kinematics, muscular pre-activation, vertical ground reaction force and tibial acceleration) were assessed during a leg-extended stepping-down task designed to mimic the characteristics of running impacts. Shoes’ aging led to increased ST (means: from 127 to 154 N ? mm^?1) and decreased energy dissipation (viscosity) (means: from 2.19 to 1.88 J). The effects induced by mechanical changes on body kinematics were very small. However, they led with the elastic shoe to increased vastus lateralis pre-activation, tibial acceleration peak (means: from 4.5 g to 5.2 g) and rate. Among the three shoes tested, the shoe with intermediate midsole foam provided the best compromise between viscosity and elasticity. The optimum balance remains to be found for the design of shoes regarding at once cushioning, durability and injury prevention.     

‘Libre’ software: turning fads into institutions?

The article presents an economic analysis of Libre software and of its sustainability as a new economic model for software. We underline the role of Libre software development communities and analyze incentives for both kernel and obscure developers. We emphasize the role of the so-called ‘public’ licenses to provide an appropriate institutional framework. We show that several features of Libre software also allow it to improve faster than proprietary software, and therefore to achieve strong market performance when competing against existing standards, even when proprietary software producers react. We illustrate our point using a simple local and global interaction model to study the technological competition between Linux and Windows on the server operating system (OS) market. We finally argue that if sufficient initial momentum could be created through public intervention Libre software could turn from a fad into an efficient economic institution to correct inefficiencies due to network externalities.     

Neuromyths Among Teachers and Student Teachers

Many so‐called brain‐based educational approaches have been strongly criticized for their lack of empirical support and occasionally for their use of pseudoscientific concepts. As a result, several use the term neuromyths to refer to false beliefs or misinterpretations regarding neuroscientific facts. We surveyed both teachers and student teachers concerning their agreement toward hemispheric dominance, modality dominance, and the Brain Gym© method. Results suggest that teachers as well as student teachers believe in the reality of hemispheric and modality dominance but only a few were aware of the Brain Gym© method. Correlation analyses show moderate relationships across different beliefs and/or their perceived benefits in education. Teachers believed more than student teachers in hemispheric dominance and its pedagogical relevance. Together with other studies, the results suggest that teachers and student teachers could benefit from appropriate training in this new field of research.     

Differential effects of endurance and resistance training on central fatigue

The effect of long-term endurance and resistance training on central fatigue has been studied using transcranial magnetic stimulation by exercising the biceps brachii to exhaustion and recording motor-evoked potentials from the non-exercised homologous biceps. Three groups of eight healthy individuals took part: two groups of individuals who had more than 8 years of athletic training in either an endurance or resistance sport, and a group of controls. The size of a motor-evoked potential (area of averaged rectified response) was significantly depressed in all three groups in the non-exercised arm after exhaustive exercise of the opposite arm. Recovery of motor-evoked potentials occurred earlier in endurance athletes (20 min) than in control participants (30 min) and resistance athletes (>30 min). Dexterity and maximum voluntary contraction of the biceps for the non-exercised arm were not depressed in any group. In a separate session, the limit of endurance time for the biceps was reduced significantly following exhaustive exercise of the biceps of the other arm for resistance athletes and control participants, whereas there was no change in the endurance athletes. Our findings suggest that athletic training has an effect on the mechanism of central fatigue that may be specific to the nature of training.     

Educating in the Seventh Fire: Debwewin,Mino‐bimaadiziwin,and Ecological Justice

The Anishinaabe Seven Fires Creation Story can be read as a theory on which all human beings share a fundamental love of reflecting reality in what they think and do. In this article, Marc Kruse, Nicolas Tanchuk, and Robert Hamilton argue that this ethical theory is correct but that the colonial ideology taught in our schools can obscure our knowledge of this fact. Specifically, the authors claim that decolonizing education requires teaching students and teachers alike to see the presence of value whenever they encounter other beings animated by a responsiveness to reality. All living things strive to perceive and respond to reality — to live and continue to learn — even if epistemic faculties differ. All living things, then, the authors conclude, are rightly seen as our relatives and kin, as bearers of value to whom we owe moral respect, as Anishinaabe elders have long taught.     

利用PVM实现整体光照的并行计算

对利用网络资源解决复杂且耗时的计算问题做了尝试 .选择典型的粒子跟踪整体光照计算问题作为研究对象 ,提出一种改进的且充分发掘其内在相关特性的密度估计算法 .在以太网连接的多台微机上 ,以PVM (并行虚拟机 )机制实现了该算法的并行计算 .通过对各项运算性能指标的测试与分析 ,结果显示可获得良好的加速比 ,并且PVM在分布式网络并行计算上将有很好的应用前景