不确定条件下的最优储蓄策略

使用Solow型的单部门新古典增长模型,其中资本-劳动比率可以用扩散随机过程描述.以储蓄函数为常数的Cobb-Douglas函数为特例,主要研究了在不确定条件下如何制定最优储蓄策略的问题,并且推导出该问题与仅包括稳态分布的从属问题两者之间具有一致性,这是从随机情形归纳出的结论,从而为投资者提供了理论根据.     

地球关键带与地表通量综合观测研究为黄土高原生态保护和可持续发展提供有力的科技支撑

中国科学院黄土高原地球关键带与地表通量野外观测研究站（以下简称“黄土高原关键带站”）立足黄土高原，面向黄河中游，开展季风区地球关键带和地表通量的长期定位观测和数据积累，在科学上为世界地球关键带科学作出突出贡献，在服务国家需求上为黄河流域生态保护和高质量发展等国家战略提供有力的科技支撑。黄土高原关键带站提出了黄土关键带形成演化的“季风控制论”，重建了地质历史时期黄土高原植被、温度和降水的变化，查明了黄土关键带形成演化的气候背景；重建了过去500年温度、降水等气候要素序列，揭示了黄土高原干旱、高温等极端气候事件发生的诱因及特点；系统开展了黄土高原生态系统过程与服务研究，揭示了黄土高原关键带土地利用格局与生态过程的作用机理，阐明了不同生态系统服务的形成与相互作用机制，提出了面向可持续发展的黄土高原关键带类型划分的指标体系和方法框架；深入开展了黄土高原多尺度水土过程及其对重大生态工程的响应研究，阐明了黄土高原和黄河流域过去60年径流输沙和水沙关系的时空尺度特征与驱动机制，揭示了土壤水分与区域气候、土壤和植被的相互关系，定量评估了黄土高原生物和工程治理措施的环境效应；为黄土高原综合治理、生态保护和经济社会可持续发展提供决策咨询。     

中国北方沙区水量平衡自动模拟监测系统（沙坡头蒸渗仪群）

水量平衡始终是我国北方沙区植被建设所面临的核心科学问题,决定着植被-土壤系统的可持续性和稳定性。蒸发渗漏仪(以下简称"蒸渗仪")是研究水量平衡的最可靠手段,但其目前存在研究站点单一、系统不匹配、精度不一致等问题,从而制约了沙区生态水文学研究的理论创新。在中国科学院野外站网络重点科技基础设施建设项目的支持下,中国科学院沙坡头沙漠研究试验站于2019年建成了目前规模最大的中国北方沙区水量平衡自动模拟监测系统——沙坡头蒸渗仪群。该平台以36台大型称重式蒸渗仪为主体,集成了降水和地下水模拟、根系动态测量和土壤溶液提取等系统,配置了不同生物气候带沙区的土壤和典型固沙灌木,开发了数据管理信息系统。该平台可模拟降水和地下水,连续精确监测土壤水动态、蒸散发、植物生长等过程,实现不同生物气候带沙区水量平衡的自动监测-模拟-量化-集成研究,是科学认知、客观解析沙区植被-土壤系统生态水文互馈机制,探索植物固沙模式及沙区生态恢复与重建理论的重要研究平台。该平台显著提升了我国野外站的科学研究能力和解决国家重大科技需求的能力。     

复杂系统视角下的组织学习动态过程研究

组织是一个具有无尺度网络结构的复杂系统。组织学习作为组织获取核心竞争力和可持续发展能力的重要手段,是一个动态的过程:从组织学习发生的载体来看,主要有个人、团队和组织等三个层次;就组织学习发生的方式来看,包括单环学习、双环学习和三环学习等三种模式;而从组织学习过程本身来看,则分为直觉感知、解释说明、归纳整合和制度化等四个子过程。本文在系统回顾相关研究成果的基础上,从复杂系统的角度对组织学习过程进行了系统的模型整合和创新,对复杂系统环境下如何构建学习型组织的可能遇到的障碍进行了一系列的分析。     

Learning-based curriculum development

This article is written to inspire curriculum developers to centre their efforts on the learning processes of students. It presents a learning-based paradigm for higher education and demonstrates the close relationship between curriculum development and students’ learning processes. The article has three sections: Section “The role of higher education (HE) institutions” presents a discussion of the role of higher education in the knowledge society. Section “Contextual learning” presents the paradigm of contextual learning which we see as a useful foundation for curriculum development. Section “Curriculum development in practice—the BETA course” shows how a particular course in Business Economic Theory and Analysis has been developed using this paradigm. The article will be of interest to all academics interested in students’ learning processes but is especially relevant to those responsible for curriculum development.     

Integrating the big-fish-little-pond effect,the basking-in-reflected-glory effect,and the internal/external frame of reference model predicting students’ individual and collective academic self-concepts

The present research is the first to integrate three major theories of academic self-concept formation into one framework: the big-fish-little-pond effect (BFLPE), the basking-in-reflected-glory effect (BIRGE), and the internal/external frame of reference (I/E) model. For separating the BFLPE and the BIRGE, we introduced students’ collective self-concepts, defined as their perceptions of domain-specific abilities of their group (e.g., their class). We tested our newly developed model, predicting students’ math and verbal self-concepts, in the field (N = 2,001 students from 110 classes) and in the laboratory (N = 315 students in groups of three). In both studies, we found support for (1) the BFLPE (i.e., negative effects of group-average achievements on individual self-concepts within domains), (2) the BIRGE (i.e., positive effects of collective self-concepts on individual self-concepts within domains), and (3) the I/E model (i.e., positive/negative effects of individual achievements on individual self-concepts within/between domains). Moreover, for the first time, we have largely replicated the I/E model relations for predicting students’ collective self-concepts by their group-average achievements. Interestingly, the BIRGE exceeded the BFLPE in both studies. This finding demonstrates the high suitability of collective self-concepts for operationalizing the BIRGE. Overall, our findings substantially enhance our knowledge of the cognitive processes involved in students’ self-concept formation.     

Self-regulated learning by writing learning protocols: Do goal structures matter?

Having students write learning protocols is an established follow-up task to course work that elicits processes of self-regulated learning. To date, a wealth of research has focused on optimizing the learning protocol task itself by integrating instructional support measures such as prompts. By contrast, research that focuses on optimizing the context in which learning protocol writing is embedded is widely missing. In the present study, we approached this gap by focusing on the role of the contextual factor goal structure. Specifically, in an experiment with N = 166 high school students we tested whether embedding the learning protocol task in a mastery goal structure would be more beneficial than embedding it in a performance goal structure. The mastery goal structure fostered metacognitive processes, learning outcomes, and learning efficiency. We conclude that considering contextual factors such as the goal structure is crucial for understanding and optimizing the effects of learning protocols.     

Favouring reflexivity in technology-enhanced learning systems: towards smart uses of traces

During learning activities, reflexive processes allow learners to realise what they have done, understand why, decide on new actions and gain motivation. They help learners to regulate their actions by themselves, that is, to develop metacognitive regulation skills. Computer environments can support reflexive processes to support human learning, for example by analysing traces of learner activity and providing synthetic views by the way of indicators. Nevertheless, traces are underused in technology-enhanced learning (TEL) systems. In this article, we draw up the potential and limits of TEL systems based on traces for reflexive purposes. We then highlight the characteristics which TEL systems should have to use traces to foster reflexivity. We finally discuss how systems could enrich the self-confrontation process with traces.     

大学英语教师教学反思的过程及策略

教学反思,是近年来倍受国内外推崇的教学理论。因其具有将"学会教学"与"学会学习"结合起来的实践合理性而成为一股强劲的教学思潮,备受教育界的广泛关注。阐述教学反思对大学英语教师成长的重要意义,分析了在大学英语教学中教学反思的一般过程,以及提高大学英语教师教学反思能力的策略。