How pre-service teachers navigate trade-offs of food systems across time scales: a lens for exploring understandings of sustainability

In response to the increasing recognition of the need for sustainable food systems, research on students’ and educators’ knowledge of food systems and sustainability more broadly has grown but has generally focused on what people ‘fail’ to understand. Moving away from this deficit approach, the present study used semi-structured interviews to explore how 12 pre-service teachers (PSTs) in the US consider sustainability in terms of the trade-offs – or concurrent costs and benefits – associated with using different agricultural resources over short, medium, and long terms. Drawing upon the constructs of framing, metacognition, and complex causality, the study found that the majority of PSTs referred to indirect experiences of seeing or hearing about agricultural resources to demonstrate stable knowledge of short-term trade-offs and construct tentative knowledge about medium-term trade-offs. Few described long-term trade-offs. Most participants also acknowledged some gaps in their knowledge in discussing trade-offs across the different time scales. Findings suggest the importance of leveraging and building upon educators’ (and ultimately students’) prior experiences to build their understanding of complex trade-offs that underlie food systems. The study also illustrates the value of using the concept of trade-offs across time scales to explore people’s conceptions and understandings of sustainability.     

大学决不只是与时俱进

是否与时俱进,得从时间、时势、时价等几方面综合判定。大学应是远远走在时势前面的机构,这有赖于大学保有其独立品格,不可能一切皆与时俱进。在理论与应用中,后者才比较需要与时俱进。理论的力量、思想的力量让大学把视野投向遥远的未来,大学是走在时间前面的,超越时限,超越时势。     

教育学是科学吗？——教育一个基本性质的发现及其对政策取向的意义

本文提出并分析了教育学危机的根源,揭示了教育的一个基本性质,即教育不是一种本源现象,而是一种派生现象;不是一种本体现象,而是一种从属现象。本文简要论证并分析了知识的一个显著特征,由此从各个角度探讨了教育对知识的派生和从属性质。由这一基本性质的揭示,作者对政策取向或政策侧重点做出阐述：教育学只有在揭示教育的真实性质和关系...     

从平行研究角度看《十日谈》和《拍案惊奇》中爱情主题之比较

本文借助比较文学美国学派平行研究的有关理论、方法,对《十日谈》和《拍案惊奇》两部作品中爱情主题的异同点进行比较分析,以探讨它们之间的内在联系和美学价值。     

关于筛选16～18岁中学生体质综合评价中心理指标问题的初步研究

心理评价是体质综合评价中不可缺少的重要部分。文章通过对重庆市近600名16～18岁健康男女中学生的测试,以及文献资料的综合研究,对筛选体质综合评价中心理指标的相关问题——心身关系作了较为深入的研究。研究发现,心身在机能上存在相互影响,相互作用,但其机能水平之间却没有数量上的线性关系。通过较为系统的分析讨论,还初步提出将16PF 中的13项指标列为体质综合评价中的心理指标。     

Game interruptions in elite soccer

Abstract

The objectives of the study were to analyse game interruptions of league soccer in detail and the tactical use of game interruptions. Sixteen matches of a German first league soccer team were observed. An observational system was designed to assess interruption types, score, duration of interruption, location of interruption, time of interruption and number of occurrences. Results showed that there is an average of 108 interruptions per match. Throw-ins (40) and free kicks (33) were most frequent. Goal kicks (17), corner kicks (10), substitutions (4), and kick offs (3) occurred less often. Drop balls, penalties, and injuries occurred least often. For 38% of the total match time observed, matches were halted. The mean duration of running and interrupted match parts were 32.1 s and 18.7 s, respectively. The analysis showed significant differences concerning the influence of the location of interruption, score, and time of interruption on the duration of different interruption types (P < 0.05). The results of the study showed the tactical use of game interruptions during league soccer matches, e.g. goal kicks of the leading team take longer towards the end of the match. Examining game interruptions has turned out to be a valuable source of information adding to our knowledge of soccer. We have shown evidence that the durations of many interruptions serve tactical purposes, a well-known hypothesis in practice.     

对测定过磷酸钙中有效磷的钒钼黄比色法的一点改进

对钒钼黄比色法进行了改进。在浸提过磷酸钙中有效磷时,将65℃水浴1小时改进为85℃水浴30分钟,其余步骤仍按原方法进行。结果发现,改进前后测定结果之间无显著差异,改进法还具有省时、精密度高的优点。     

多巴胺与运动能力的关系

多巴胺主要生理功能是调节躯体运动、神经活动等。脑中的多巴胺合成和分解与运动能力有密切的关系,其含量的增加可以提高运动能力,尤其是耐力运动能力,多巴胺还可以通过调节其他激素以及影响心血管来影响运动能力;多巴胺也与运动性中枢疲劳有联系;多巴胺合成和分泌异常与帕金森综合征并伴有迟发型运动障碍有关。本文对多巴胺与运动能力之间的关系做一综述。     

用EPROM设计定时控制电路

简介了ＥＰＲＯＭ及其管脚功能，阐述了用ＥＰＲＯＭ设计定时控制电路的方法和技巧，并以多路定时控制电路和循环定时控制电路的实际应用例子进行说明，最后讨论了用软件代替硬件设计组合逻辑电路方法的优越性．     

线性离散系统的H∞开环迭代学习控制器设计

针对线性离散系统,研究了开环动态迭代学习控制律的设计问题.首先给出了闭环系统的收敛充分条件,然后把迭代控制转化为H∞设计问题,最后利用线性矩阵不等式（LMI）方法求解迭代学习控制器.通过仿真实例表明了设计方法的有效性.