Spatial concentration distribution analysis of cells in electrode-multilayered microchannel by dielectric property measurement

The spatial concentration distribution of cells in a microchannel is measured by combining the dielectric properties of cells with the specific structure of the electrode-multilayered microchannel. The dielectric properties of cells obtained with the impedance spectroscopy method includes the cell permittivity and dielectric relaxation, which corresponds to the cell concentration and structure. The electrode-multilayered microchannel is constructed by 5 cross-sections, and each cross-section contains 5 electrode-layers embedded with 16 micro electrodes. In the experiment, the dielectric properties of cell suspensions with different volume concentrations are measured with different electrode-combinations corresponding to different electric field distributions. The dielectric relaxations of different cell concentrations are compared and discussed with the Maxwell-Wagner dispersion theory, and the relaxation frequencies are analysed by a cell polarization model established based on the Hanai cell model. Moreover, a significant linear relationship with AC frequency dependency between relative permittivity and cell concentration was found, which provides a promising way to on-line estimate cell concentration in microchannel. Finally, cell distribution in 1 cross-section of the microchannel (X and Y directions) was measured with different electrode-combinations using the dielectric properties of cell suspensions, and cell concentration distribution along the microchannel (Z direction) was visualized at flowing state. The present cell spatial sensing study provides a new approach for 3 dimensional non-invasive online cell sensing for biological industry.     

Delayed intermodal contingency affects young children's recognition of their current self

This study investigated whether 2-, 3-, and 4-year-olds use their video feedback as a reflection of their current state, even when their feedback was presented with a short temporal delay. In Experiment 1, the effects of 1- and 2-s delayed feedback were examined on an analog of the mark test. In the case of live and 1-s delayed feedback, 3-year-olds passed the test; however, they failed in the case of 2-s delayed feedback. Experiment 2 examined the effect of prior experience of delayed contingency and explorative behavior. The results showed a significant effect of prior experience. These results suggest that detection of visual-proprioceptive contingency contributes to recognition of visual feedback as one's current self.     

A ski robot system for qualitative modelling of the carved turn

A robot that simulates a number of human leg joint motions during carved turns has been developed. Each leg had six degrees of freedom like those of human athletes. An on-board computer controlled the sequence of joint angles in an open-loop mode during skiing on an artificial grass slope. The relations among joint motions, reacting forces and turn trajectory were investigated by programming various motions of the robot. At first, the effect of basic joint motions, such as abduction–adduction and flexion–extension of the hip, knee and ankle joints were investigated. Then the sequence of a top athlete’s joint motions, measured in a separate study, was applied to investigate its effect on the ski turn. The human-inspired programme produced a more even force balance between the skis and also a higher-quality turn. The requirements for a successful physical model of a human skier are discussed.     

青少年乒乓运动员的焦虑和运动成绩关系

多维焦虑理论认为认知和躯体焦虑对运动成绩会产生不同的影响.根据这个理论,运动员在赛前具有较高的认知焦虑水平或躯体焦虑水平出现极端值(过高或过低)或自信心较低时,他们将取得较差的运动成绩.先前的研究还认为焦虑与运动成绩间的关系还取决于所要完成动作的特点.不同的运动技能有各自最佳的焦虑水平.总的来说,焦虑水平较高有利于完成体力消耗较大的运动项目.而焦虑水平较低时,则有利于完成精确类项目.就乒乓球项目而言,它既需要体力又需要精确性,因此,本研究调查分析了乒乓球运动员赛前焦虑水平与运动成绩间的关系.研究对象3 6名青少年乒乓球运动员,男、女运动员各1 8名,平均年龄为12.28±0.74岁.研究方法采用运动竞赛状态焦虑量表(CSAI-2C).让运动员在参加地区赛第一场比赛的赛前30分填写问卷.研究结果认知状态焦虑水平不能用来预测运动员的成绩.获胜运动员和失利运动员赛前的躯体状态焦虑和自信心没有差异.这表明本研究没有支持多维焦虑理论的假设,或许是乒乓球运动的特点和运动员的个体差异比运动员的焦虑水平对运动成绩的影响更大.因此,如果运动员的个人特点与他们的技术风格相适应,不同焦虑水平的运动员都可能取得好成绩.     

Openness to international markets and the diffusion of standards compliance in Latin America. A multi level analysis

This study contributes to the debate on the role of openness to international markets for the diffusion of compliance with international standards in developing countries. Relying upon aggregated data for 1995-2005, as well as upon firm-level and secondary data from the Chilean salmon farming industry, the determinants of ISO 9000 and ISO 14001 diffusion at country, industry, and firm level, in Latin American are analysed. Our evidence suggests that openness to international markets acts at different levels. At both the country and industry level, it creates awareness and access to new knowledge therefore providing economic incentives or penalisations for evaluating certification. This effect competes and complements the deliberated efforts and policies in explaining diffusion of certification. At firm level, however, openness to international markets alone does not provide sufficient opportunities to acquire the knowledge required to comply with these standards. In this case, standards’ compliance depends on firm's capability to use relational and search assets, as well as on national and industrial efforts and policies to spread standards’ usage.     

Teachers’ content knowledge about oral language: measure development and evidence of initial validity

Reading and Writing - Efforts to improve classroom language practices and children’s language learning, as a means of supporting reading comprehension, may depend on teachers’ knowledge...     

高水平乒乓球运动员正手回击不同状态来球时动作的调整

本研究旨在调查当高水平乒乓球运动员被要求对付不同状态来球时,如何调整他们的动作.研究对象与方法前巴西国家队高水平乒乓球男女运动员7名,均为右手持拍.运动员(平均年龄27.85±5.36岁、训练年限平均为19.14±5.24年,运动员身体状况良好,每周训练3次.运动员分别在4种状况下,对发球机发出的乒乓球进行正手击球(1)两次反弹(一次过网前一次过网后)的上旋球;(2)两次反弹的侧旋球;(3)一次反弹(过网后)的上旋球;(4)一次反弹的侧旋球.研究结果(1)乒乓球运动员采用包括动作的绝对和相对的修正以促进正手对击球的适应;(2)动作修正的本质受不同状况的约束;(3)细微动作(触球和随拍)比宏观动作(准备姿态和向前挥拍)更容易受外界状况的影响.分析与讨论(1)回击一次和两次反弹的侧旋球,运动员几乎不用调整,但侧旋球会造成成功率不高.在引拍、迎球挥拍阶段动作模式没有改变,但球拍触球、随势挥拍阶段稍有不同,此动作有利于还原部分;(2)击球动作前的选位和对手的动作趋势也会影响动作模式,但变化却是使整个动作结构的改变.