Connecting photosynthesis and cellular respiration: Preservice teachers' conceptions

The biological processes of photosynthesis and plant cellular respiration include multiple biochemical steps, occur simultaneously within plant cells, and share common molecular components. Yet, learners often compartmentalize functions and specialization of cell organelles relevant to these two processes, without considering the interconnections as well as the significance of the plant as an independent biological system functioning as a nested component within local and global ecosystems. Understanding connections among biological systems at macro and micro levels is important to biological literacy. This study examined preservice elementary teachers' conceptions of photosynthesis and plant cellular respiration, with attention to interconnections and systems. Participants were limited in their understanding of the processes impacting multiple ecological levels, and they held inadequate representations of interconnections between the processes. Participants' views were laden with sociological and egocentric components. They often compared plant functions with analogous human functions. Most participants viewed plants as dependent on humans while having societal use. Justifications for views included nominal knowledge of the processes; experiential authoritarian reasoning; and anthropomorphism. We discuss instructional implications in light of the findings. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 791–812, 2009     

具分布时滞SICNNs周期解的存在性

利用重合度理论和微分不等式技巧,研究了具分布时滞和变系数SICNN,周期解的存在性,获得了一些新的充分准则．本文结果补充已有文献的结论．     

Improvement of cellular health indicators and muscle quality in older women with different resistance training volumes

ABSTRACT

The main purpose of this study was to compare the effects of resistance training (RT) performed with different training volumes on phase angle (PhA), body water components, and muscle quality (MQ) in untrained older adult women. A second purpose was to assess the relationship between PhA and MQ. Sixty-two older adult women (68.6 ± 5.0 years, 65.2 ± 13.3 kg, 156.1 ± 6.2 cm) were randomly assigned into one of the three groups: two training groups performed either 1 set (G1S) or 3 sets (G3S), or a control group (CG). Body water components and PhA were estimated by bioelectrical impedance (BIA). MQ was determined by dividing skeletal muscle mass estimated by dual-energy absorptiometry (DXA) by total muscle strength from three exercises. After the intervention period, both training groups demonstrated improvements (P < 0.05) when compared with CON for intracellular water, total body water, PhA, and MQ. These results suggest that RT can improve PhA, body water components, and MQ after 12 weeks of RT in untrained older women, regardless of training volume. Furthermore, changes in MQ were positively correlated with changes in PhA (r = 0.60, P < 0.01).     

Abstracts

This study investigated the changes in urinary neopterin, a biochemical marker of cellular immune activity, in elite male rowers undertaking a progressive increase in training prior to Olympic competition. Twenty‐seven male rowers of the 1992 Great Britain team provided daily urine samples for a 4‐week period of training that included 17 days of altitude training and 10 days of heat acclimatization. The mean (± s.d.) ratio of neopterin/ creatinine in urine increased from pre‐training values of 135 ± 32 to a peak of 219± 121 μmol neopterin per mol creatinine on day 19 of training (P < 0.05). Changes in the ratio of neopterin/creatinine with training were found to be transient and highly variable between subjects, ranging from no change to peak values five‐fold greater than baseline. On the basis of the in vivo measurement of cell‐mediated immunity employed in this study, we conclude that elite athletes engaged in high‐intensity training prior to competition show either no change or a moderate increase in cellular immune activation.     

单向行人流的元胞自动机模拟研究

引入向前、向左两个偏向强度D1、D2来确定单向通道中行人向各方向运动的几率,应用元胞自动机模型对在不同偏向强度下行人的疏散过程进行模拟.结果表明,疏散时间随着向前偏向强度的D1增大而减少;D2对疏散时间的影响随着通道宽度和D1的不同而不同.     

教室内行人疏散的元胞自动机模拟研究

针对具有两个出口并由桌椅构成多条通道的教室建立了行人疏散的元胞自动机模型,进行计算机模拟的结果表明:行人根据到出口的距离和行人拥挤程度两个因素来选择出口和目标网格能缩短疏散时间;出口的宽度对疏散过程有一定的影响,但随着出口宽度的增大,对疏散的影响越来越小。     

构建我国证人作证特免权制度

我国现行立法规定了证人的作证义务,但在司法实践中证人不作证、不出庭的现象严重。观古今中外立法例,从历史发展和基本人性角度出发,赋予特定公民以证人作证特免权,有利于改变证人拒绝作证的现状,维护特定的社会关系。因此,构建我国的证人作证特免权制度,应制定好适用的原则与范围,并完善相应配套机制,以有效解决实践问题,实现利益均衡。     

B基于组织免疫视角的企业适应性研究/B

本文借鉴了生物学、医学领域的研究成果,从组织免疫这一新的视角解释组织的适应性问题。在界定组织免疫概念和描述运行机制的基础上,提出组织免疫行为包括组织认知、组织防御、组织记忆三个维度的假设。通过设计相应的量表,并通过问卷调查的方式收集数据,对数据进行因子分析,验证了假设;最后对研究结果的理论和实际意义进行了总结,并指出未来的研究方向。     

文学中的后现代伦理:晚期德里达、莫里森及其他

本文从后现代伦理的角度分析了托妮.莫里森的小说《宠儿》中塞丝杀婴行为所产生的伦理的悖论性,同时揭示了社群中所蕴涵和运作的矛盾结构,即晚期德里达所论述的免疫性与自身免疫性逻辑:每个社群在自我保护的同时,又在针对自身。这种结构存在于不同层面,美国的南北战争、黑人社群、塞丝同自己孩子的关系,甚至当前的反恐斗争都遵循这种逻辑。最后,本文指出,文学对于我们理解和把控当前世界局势的种种机制有着独特的优势和不可替代的作用。     

基于CA的城市扩展动态模拟与预测

城市扩展动态过程的模拟与预测可以为区域发展、城市规划和管理等提供决策依据 .传统的各种城市模型不能完整地表示城市动态过程的时空信息和时空关系 ,通常将空间抽象为均质平原或简单功能区 ,将时间作为一个变量纳入方程 ,缺乏对城市动态系统的直接模拟 .细胞自动机 (CellularAutomata)是一种“自下而上”的动态模拟建模框架 ,具有模拟复杂系统时空演化过程的能力 .本文将标准CA模型的四元组进行了扩展以满足GIS环境下的城市扩展动态模拟的要求 ,建立了土地持续利用动态模拟模型 .运用此模型对包头市城市扩展进行了比较成功的模拟和对未来 1 5年城市发展趋势进行了预测 .