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This study investigated relationships between social media motivation, relative preferences for social media type, and network heterogeneity, using a U.S. national survey. By classifying social media into the symmetrical and the asymmetrical, we showed that relationship motivation was more likely to be associated with a preference for the symmetrical type, whereas information motivation with a preference for the asymmetrical. Network heterogeneity was positively predicted by relationship motivation but not by information motivation. Finally, a relative preference for the symmetrical type was found to mediate the association between relationship motivation and network heterogeneity. 相似文献
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This paper examines the factors affecting the performance of global query expansion based on term co-occurrence data and suggests a way to maximize the retrieval effectiveness. Major parameters to be optimized through experiments are term similarity measure and the weighting scheme of additional terms. The evaluation of four similarity measures tested in query expansion reveal that mutual information and Yule's Y, which emphasize low frequency terms, achieve better performance than cosine and Jaccard coefficients that have the reverse tendency. In the evaluation of three weighting schemes, similarity weight performs well only with short queries, whereas fixed weights of approximately 0.5 and similarity rank weights were effective with queries of any length. Furthermore, the optimal similarity rank weight achieving the best overall performance seems to be the least affected by test collections and the number of additional terms. For the efficiency of retrieval, the number of additional terms needs not exceed 70 in our test collections, but the optimal number may vary according to the characteristics of the similarity measure employed. 相似文献
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The present experiment examined the learning effects of participants self-controlling their receipt of knowledge of results (KR) on all or half of their acquisition trials (50%). For participants who were provided 50% self-control, the first half of their acquisition period consisted of receiving KR on all trials, or according to a faded-KR schedule. Participants practiced a sequential timing task. The results showed that independent of practice condition, participants who self-controlled their KR during the acquisition period demonstrated superior performance compared to the respective yoked conditions in the retention and transfer portion of the experiment. These results extend previous research by suggesting that decreasing the proportion of self-control trials does not compromise learning in a self-controlled context. 相似文献
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Scott C. Ellis Thomas J. Goldsby Ana M. Bailey Jae‐Young Oh 《Decision Sciences Journal of Innovative Education》2014,12(4):287-319
Lean six sigma is a management methodology that firms can employ to achieve substantial improvement in supply chain performance. However, few pedagogical exercises facilitate students’ use of a comprehensive set of lean six sigma principles within a supply chain context. We describe the Airplane Supply Chain Simulation that helps students understand how lean six sigma concepts may be leveraged to improve supply chain performance. The basis of this simulation is a four‐tier supply chain, consisting of suppliers (two tiers), a manufacturer, and a customer, that produces three models of paper airplanes to meet randomly distributed customer demand. In the first of three successive runs, a highly structured simulation is executed in which supply chain roles are well defined, material flows are convoluted, and a “push” production strategy is followed. The first simulation as the “current state” and, for the second and third simulation runs, challenge competing student teams to leverage lean six sigma concepts to develop a “future state” that enables the fulfillment of all customer orders at the lowest cost. Results based on statistical analyses of survey response data from 194 MBA students show that the Airplane Supply Chain Simulation is an effective participative, team‐based learning tool. 相似文献
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Lee K Kim C Young Yang J Lee H Ahn B Xu L Yoon Kang J Oh KW 《Biomicrofluidics》2012,6(1):14114-141147
We propose a simple method for forming massive and uniform three-dimensional (3-D) cell spheroids in a multi-level structured microfluidic device by gravitational force. The concept of orienting the device vertically has allowed spheroid formation, long-term perfusion, and retrieval of the cultured spheroids by user-friendly standard pipetting. We have successfully formed, perfused, and retrieved uniform, size-controllable, well-conditioned spheroids of human embryonic kidney 293 cells (HEK 293) in the gravity-oriented microfluidic device. We expect the proposed method will be a useful tool to study in-vitro 3-D cell models for the proliferation, differentiation, and metabolism of embryoid bodies or tumours. 相似文献
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This study attempts to provide a new perspective on current shifts in knowledge production through analysing the relationship between research and education. The study, based on interviews and questionnaires, focuses on the interaction within applied research centres with a close industry cooperation. The results suggest that the interaction between research and education benefits from a collaborative environment, since researchers hold positive attitudes towards integrating research, education and collaboration, and students are given the opportunity to work within applied research projects. The findings are discussed in terms of researchers’ ability to handle their scholarly tasks of research, teaching, and collaboration, and the importance for acknowledging research collaborations from both research and teaching perspectives. 相似文献
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Sudhir Kurl Sae Young Jae Timo H.Makikallio Ari Voutilainen Magnus J.Hagnas Jussi Kauhanen Jari A.Laukkanen 《运动与健康科学(英文)》2022,11(2):266-271
Background:Little is known about exercise cardiac power(ECP),defined as the ratio of directly measured maximal oxygen uptake with peak systolic blood pressure during exercise,on heart failure(HF)risk.We examined the association of ECP and the risk of HF.Methods:This was a population-based cohort study of 2351 men from eastern Finland.The average time to follow-up was 25 years.Participants participated at baseline in an exercise stress test.A total of 313 cases of HF occurred.Results:Men with low ECP(<9.84 mL/mmHg,the lowest quartile)had a 2.37-fold(95%confidence interval(95%CI):1.68-3.35,p<0.0001)hazards ratio of HF as compared with men with high ECP(>13.92 mL/mmHg,the highest quartile),after adjusting for age.Low ECP was associated with a 1.96-fold risk(95%CI:1.38-2.78,p<0.001)of HF after additional adjustment for conventional risk factors.After further adjustment for left ventricular hypertrophy,the results hardly changed(hazards ratio=1.87,95%CI:1.31-2.66,p<0.001).One SD increase in ECP(3.16 mL/mmHg)was associated with a decreased risk of HF by 28%(95%CI:17%-37%).Conclusion:ECP provides a noninvasive and easily available measure from cardiopulmonary exercise tests in predicting HF.However,ECP did not provide additional value over maximal oxygen uptake. 相似文献
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Often, the evidence we observe is consistent with more than one explanation. How do learners discriminate among candidate causes? The current studies examine whether counterfactuals help 5-year olds (N = 120) select between competing hypotheses and compares the effectiveness of these prompts to a related scaffold. In Experiment 1, counterfactuals support evidence evaluation, leading children to privilege and extend the cause that accounted for more data. In Experiment 2, the hypothesis that accounted for the most evidence was pitted against children’s prior beliefs. Children who considered alternative outcomes privileged the hypothesis that accounted for more observations, whereas those who explained relied on prior beliefs. Findings demonstrate that counterfactuals recruit attention to disambiguating evidence and outperform explanation when data contrast with existing beliefs. 相似文献
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Teaching practicum experiences, including those in international contexts, are based on partnerships between institutions and host schools, and the partnership between the pre-service teacher, the cooperating teacher and the university supervisor. This article explores the relationship between pre-service teachers and cooperating teachers in an international practicum in the Solomon Islands. It considers the way the cooperating teachers were positioned within the partnership, and raises questions about the way the university engages with host schools and teachers in international contexts, particularly in developing countries. Drawing on postcolonial theory, we investigate the complexity and contradictions in relationships between the pre-service teachers and cooperating teachers. We conclude by offering suggestions for valuing the role of cooperating teachers in these contexts. 相似文献