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In this study, we present the long-term influence of an after school science practicum associated with an elementary science methods course. The practicum or field experience could be considered a community-based service learning programme as it is situated both within and for the community. Study participants included eight third- and fifth-grade teachers who had participated in elementary science methods courses; four of these teachers participated in the after school teaching practicum while four participants experienced a more traditional observation-based elementary science practicum. All of these teachers were in their second or third year teaching which was 3–4 years after taking the methods course. Investigation methods included questionnaires, field observations and semi-structured, individual interviews. Teachers more regularly utilised reform-based teaching strategies and cited the after school teaching practicum as preparing them to use these strategies in their own classrooms. All teachers exhibited a growth mindset to some degree, but the after school practicum participants did demonstrate a wider use of reformed-based teaching strategies and a higher growth mindset. Elementary teachers perceive risk associated with these key aspects of instruction: (1) managing instruction and classroom management, (2) teaching science through guided inquiry, and (3) overcoming adoptions in other ‘mandated’ curriculum like math and reading. 相似文献
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Girl Scouts aims to foster leadership by encouraging girls to discover themselves, make connections, and take action to make the world better. This paper chronicles the five-year journey of eight professional mothers of color who sought to provide their daughters with a space to ‘think and live differently’ as Girl Scouts and young women of color in (post)colonial Hawai‘i. Through questionnaires and a semi-structured focus group interview, mothers reflect on their original intentions to create a ‘safe space’ for their daughters to engage with the politics of gender, race, and class and to rethink, review, and rework their identities. Mothers’ reflections reveal success in creating safe spaces for the critical analysis of gender, but comparatively less success in critical analyses of race and class – a phenomenon that the mothers suggest may have been complicated by (1) the enduring myth of Hawai‘i as a multicultural paradise, (2) Girl Scouts’ assimilationist history, and (3) the mothers’ own relatively privileged positions. 相似文献
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This paper will offer some insights into possible ways to optimise the blended learning environment based on experience with this modality of teaching at Arab Open University/Jordan branch and also by reflecting upon the results of several meta-analytical studies, which have shown blended learning environments to be more effective than their face to face and online only counterparts. Three key elements will be presented as important ways for improving the blended learning environment: forging genuine collaborative partnerships between institutions in terms of the team-writing of Open and Distance Learning (ODL) material, adopting a more theoretically based instructional approach, such as the cognitive apprenticeship (CA) model, which emphasises making thinking visible and developing a comprehensive understanding of blended education in order to help students achieve their educational goals. 相似文献
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在双积分制背景下,通过构建产业链自制式决策和外购式决策模型,研究了新能源汽车产业链中乘用车生产企业和电池生产企业的最优决策问题。结果表明:消费者支付意愿的提高、电池生产企业的研发能力的提升、市场上新能源汽车积分交易价格的上涨,都有利于两种决策产业链中新能源汽车续航能力的提高;自制式决策更有效,但外购式决策产业链可以通过提升消费者支付意愿、提高电池企业的研发能力来达到自制式决策产业链利润的效果。在外购式决策产业链中引入了政府补贴机制,实现产业链良性发展。在此基础上,给出了新能源汽车产业发展的建议。 相似文献
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Liang Liu Shengyuan Xu Xue-Jun Xie Bing Xiao 《Journal of The Franklin Institute》2019,356(16):9627-9645
This paper investigates the problem of observer-based decentralized control for a class of large-scale stochastic high-order feedforward systems with multi time delays. By using the homogeneous domination idea and constructing the implementable observer, the decentralized output-feedback controller design scheme is firstly proposed. Then, with the aid of stochastic time delay system stability theory, the globally asymptotically stable in probability of the closed-loop system is verified by selecting an appropriate Lyapunov–Krasoviskii functional. Finally, an example is provided to demonstrate the efficiency of the proposed design method. 相似文献
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目的:探讨不同负荷运动训练对大鼠骨骼肌线粒体三羧酸循环的影响及其机制。方法:将雄性Wistar大鼠50只随机均分为5组:安静对照组(C)、低负荷运动训练组(LT)、中等负荷运动训练组(MT)、高负荷运动训练组(HT)和极高负荷运动训练组(ST),每组10只。各运动组分别进行6周的跑台运动训练。训练方案结束后,取腓肠肌样本,提取线粒体,测定线粒体柠檬酸合成酶(CS)、异柠檬酸脱氢酶(ICD)和α-酮戊二酸脱氢酶(α-KGDHC)活性;线粒体Ga2+含量、胞浆NADH、NAD+、ATP和ADP含量,以及ICD mRNA转录水平。结果:(1)不同负荷运动训练组线粒体CS、ICD和α-KGDHC的活性均显著高于安静对照组(P < 0.01),且CS和ICD活性由高到低顺序均为:MT组 > HT组 > ST组 > LT组 > C组,α-KGDHC活性由高到低顺序为:HT组 > MT组 > ST组 > LT组 > C组。(2)不同负荷运动训练组线粒体Ca2+ 含量均显著高于安静对照组(P < 0.01),其含量由高到低顺序为:MT组 > HT组 > ST组 > LT组 > C组;胞浆NADH/NAD+和ATP/ADP的比值均显著低于安静对照组(P < 0.01),其比值由低到高顺序为:MT组 < ST组 < HT组 < LT组 < C组。(3)不同负荷运动训练组ICD mRNA转录水平均高于安静对照组(P < 0.01),其水平由高到低顺序为: MT组 > HT组 > ST组 > LT组 > C组。结论:低负荷、中等负荷、高负荷及极高负荷运动训练均可提高大鼠骨骼肌线粒体三羧酸循环功能,且中等负荷运动训练效果最佳。其机制与胞浆NADH/NAD+和ATP/ADP比值、线粒体摄钙能力及限速酶基因的表达有关。 相似文献
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Jianzhong Zhou Yuncheng Zhang Yang Zheng Yanhe Xu 《Journal of The Franklin Institute》2018,355(10):4131-4146
The hydraulic turbine governing system plays an indispensable role in maintaining the stability of electrical power system. In this paper, synergetic control theory is introduced to enhance the regulating ability of the hydraulic turbine governing system. For the purpose of describing the characteristics of objective system and deducing the synergetic control rule, a nonlinear mathematic model of a hydraulic turbine governing system with long tail race and two surge tanks is established. Furthermore, the nonlinear characteristic of the hydraulic turbine is described by six variable partial derivatives. For further investigation, the hydraulic turbine governing system is conducted to running under load condition when its coaxial generator connects to an infinite bus. Simulation experiments have been made under both load disturbance and three-phase short circuit fault conditions to compare the dynamic performances of proposed synergetic governing controller and classic PID controller. The results indicate that the proposed synergetic governing controller is an effective alternative in normal condition and a superior one in emergency. Moreover, the robustness of synergetic governing controller has also been discussed at the end of this paper. 相似文献
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Xu-Guang Li Jun-Xiu Chen Silviu-Iulian Niculescu Arben Çela 《Journal of The Franklin Institute》2018,355(17):8683-8697
Most of the reported Lotka–Volterra examples have at most one stability interval for the delay parameters. Furthermore, the existing methods fall short in treating more general case studies. Inspired by some recent results for analyzing the stability of time-delay systems, this paper focuses on a deeper characterization of the stability of Lotka–Volterra systems w.r.t. the delay parameters. More precisely, we will introduce the recently-proposed frequency-sweeping approach to study the complete stability problem for a broad class of linearized Lotka–Volterra systems. As a result, the whole stability delay-set can be analytically determined. Moreover, as a significant byproduct of the proposed approach, some Lotka–Volterra examples are found to have multiple stability delay-intervals. To the best of the authors’ knowledge, such a characterization represents a novelty for having some insights in the population dynamics: in some situations, a longer maturation period of species is helpful for the stability of a population system. 相似文献