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In this paper, we investigate an approach to supporting students’ learning in science through a combination of physical experimentation and virtual modeling. We present a study that utilizes a scientific inquiry framework, which we call “bifocal modeling,” to link student-designed experiments and computer models in real time. In this study, a group of high school students designed computer models of bacterial growth with reference to a simultaneous physical experiment they were conducting, and were able to validate the correctness of their model against the results of their experiment. Our findings suggest that as the students compared their virtual models with physical experiments, they encountered “discrepant events” that contradicted their existing conceptions and elicited a state of cognitive disequilibrium. This experience of conflict encouraged students to further examine their ideas and to seek more accurate explanations of the observed natural phenomena, improving the design of their computer models.  相似文献   
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The proliferation of predatory or bogus journals has been recognized as a threat to academic research, and this study was conducted to discover the experiences of authors published in these journals. Eighty authors who had published in journals identified as predatory were surveyed. We asked how the authors learnt about these journals, what they thought about the reputation of the journals, their experiences of peer review and the quality of feedback provided, and whether publication was driven by PhD or job requirements. Our results showed that a third of authors discovered the journals by web searches or responding to email invitations. Over half said the reputation and name of the journal were important in selecting a journal, although a third admitted that the journal they published in did not have a good reputation. The main reason for selecting the journals was the promise of fast publication (31.2% respondents). Only half of the respondents said that publication was driven by PhD or job requirements. Just over a third reported that peer review was good or excellent, and only 17.5% said that peer review was poor or non‐existent – over 70% thought they had received good feedback from the journals. Although the research was somewhat limited, it does indicate general satisfaction with the journals in which the authors published. Fast publication coupled with good feedback and encouragement to submit can make publishing in predatory journals so tempting that few authors can resist.  相似文献   
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Material recommender system is a significant part of e-learning systems for personalization and recommendation of appropriate materials to learners. However, in the existing recommendation algorithms, dynamic interests and multi-preference of learners and multidimensional-attribute of materials are not fully considered simultaneously. Moreover, these algorithms cannot effectively use the learner’s historical sequential patterns of material accessing in recommendation. For addressing these problems and improving the accuracy and quality of recommendation, a new material recommender system framework based on sequential pattern mining and multidimensional attribute-based collaborative filtering (CF) is proposed. In the sequential pattern based approach, modified Apriori and PrefixSpan algorithms are implemented to discover latent patterns in accessing of materials and use them for recommendation. Leaner Preference Tree (LPT) is introduced to take into account multidimensional-attribute of materials, and learners’ rating and model dynamic and multi-preference of learners in the multidimensional attribute-based CF approach. Finally, the recommendation results of two approaches are combined using cascade, weighted and mixed methods. The proposed method outperforms the previous algorithms on the classification accuracy measures and the learner’s real learning preference can be satisfied accurately according to the real-time up dated contextual information.  相似文献   
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Concentrations of various trace elements are altered during pregnancy with changes in the mother’s physiology and the requirements of growing fetus. The aim of the present longitudinal study was to learn the changes of micronutrients Iron (Fe), Calcium (Ca), zinc (Zn) Magnesium (Mg) and copper (Cu) of pregnant woman and their relations with newborns levels. Serum levels of iron, calcium, zinc, magnesium and copper of 162 pregnant women and their newborns were determined by an inductively couple plasma mass spectrometer (ICP/MS). The results showed that majority (41 %) of pregnant women were in age group 26–36 years 55 % had high school and diploma levels of education and the total income ranged between 3 and 5 Rials million per month There was significant difference in iron levels during first, second and third trimesters, 76.0 ± 17.8, 63.5 ± 15.2 and 70.1 ± 14.4 μg/dl respectively. Significant difference was shown in zinc levels 79.5 ± 15, 74.5 ± 16.1, and 65.3 ± 14.9 μg/dl during three trimesters. Copper levels during pregnancy were significantly different (130.9 ± 43.5, 172.0 ± 38.94, 193.2 ± 28.5 μg/dl. The serum levels of calcium and magnesium during pregnancy were constant (Ca: 8.96 ± 0.48, 8.86 ± 0.47, 8.91 ± 0.42 mg/dl and Mg: 2.10 ± 0.21, 2.08 ± 0.28, 2.09 ± 0.29 mg/dl). Results showed that 13 % of pregnant women had hypocalcaemia and hypomagnesaemia. Thirty eight percent and 42 % of pregnant women had iron and zinc deficiency respectively. In this study, unlike zinc, no pregnant women were found deficient in serum copper levels. Calcium, iron, zinc, copper and magnesium levels in the newborn’s cord blood were 8.93 ± 0.43, 106.0 ± 26.1, 85.35 ± 16.6, 57.04 ± 13.8 and 1.99 ± 0.27 mg/dl respectively. In the present study the levels of iron and zinc in cord blood were higher than the levels of iron and zinc in maternal serum. The mean level of copper in cord blood serum in the current study was lower than maternal values. The mean serum calcium and magnesium in the serum cord blood and in the serum of the pregnant women were similar.  相似文献   
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Measurement and control of pressure-driven flow (PDF) has a great potential to enhance the performance of chemical and biological experiments in Lab on a Chip technology. In this paper, we present an optofluidic flow sensor for real-time measurement and control of PDF. The optofluidic flow sensor consists of an on-chip micro Venturi and two optical Fabry-Pérot (FP) interferometers. Flow rate was measured from the fringe shift of FP interferometers resulted from movement fluid in the on-chip micro Venturi. The experimental results show that the optofluidic flow sensor has a minimum detectable flow change of 5 nl/min that is suitable for real time monitoring and control of fluids in many chemical and biological experiments. A Finite Element Method is used to solve the three dimensional (3D) Navier–Stokes and continuity equations to validate the experimental results.  相似文献   
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Education and Information Technologies - The COVID-19 crisis has had a profound effect on higher education, especially medical education due to its sensitive nature, dealing with people’s...  相似文献   
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蛋白质糖基化修饰研究进展   总被引:2,自引:0,他引:2  
李军  杜鑫  陈玉银 《科技通报》2009,25(6):773-778,783
蛋白质翻译后修饰是蛋白质组学的一个组成部分,而蛋白质糖基化是生命体中最重要的一种蛋白质翻译后修饰之一。糖基化在细胞免疫、信号传导、蛋白翻译调控、蛋白降解等诸多生物过程中起着重要作用。随着蛋白质组学技术的不断发展,糖基化研究也越来越受到广泛的关注。本文综述了糖基化的分类、在生命体中的作用、最新的研究技术及进展。  相似文献   
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This is an annotated bibliography of peer-reviewed scholarly journals that are currently published in Iran. The titles included are a selective and representative sampling. The entry for each periodical includes the following information: title, subject, date founded, frequency, editor, price, language, publisher, address, phone number, FAX number, Web address, ISSN, circulation, indexing/abstracting sources, impact factor, ministry, and an abstract/annotation.  相似文献   
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