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Compared to parametric models, nonparametric and semiparametric approaches to modeling nonlinearity between latent variables have the advantage of recovering global relationships of unknown functional form. Bauer (2005) proposed an indirect application of finite mixtures of structural equation models where latent components are estimated in the service of more flexibly recovering characteristics of the latent aggregate regression function. This article develops and evaluates delta method and parametric bootstrap approaches for obtaining approximate confidence intervals for Bauer's semiparametric approach to modeling latent nonlinear functions. Coverage rates of these approximate point-wise confidence intervals or nonsimultaneous confidence bands are evaluated by Monte Carlo and recommendations for their use are suggested. 相似文献
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Peng-Kiat Pek 《Journal of Science Education and Technology》1996,5(3):225-233
The objective of this paper is to discuss how active student learning is possible with the aid of a CAI package for a subject such as Strength of Materials. Multimedia is the latest innovation that can be utilized to improve learning. In this study, multimedia components such as hypertext, sound, graphics, video, and animation are implemented in a CAI package. These capabilities can capture students' attention, and can also illustrate the application of knowledge to real world problems more effectively than traditional teaching methods. The other features of this package include guided examples, theory, and application tests. Guided examples show the students problem solving techniques, and provide feedback according to their responses. The theory and application tests enable the teacher to gauge the students' understanding of the subject matter. Students who do well in the theory test are eligible to attempt the application test, which poses real-world engineering problems. The lesson that can be concluded from this study is that students' problem solving skills can be improved with the aid of CAI which emphasizes anchored instructions. However, to achieve maximum benefit, students also need to possess independent learning skills. 相似文献
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Richard J. Hazler Dina L. Miller Jolynn V. Carney Suzy Green 《Educational research; a review for teachers and all concerned with progress in education》2013,55(2):133-146
Bullying and harassment by school peers has received increasing attention as their relation to personal problems and more extreme forms of violence has become better recognized. Emphases of empirical studies have focused on characteristics and behaviours of both school bullies and their victims. There is a need to place these traits and actions into the context of the situation in which they occur, in order to expand the research and allow for the development of more sophisticated and comprehensive educational, prevention and intervention programmes. A total 251 professionals (teachers and counsellors) participated in this empirical study on the ability of professionals to differentiate between bullying and other forms of conflict. Participants were asked to judge the severity of 21 scenarios depicting different combinations of situational characteristics and also whether they constituted bullying situations or not. Results indicated that physical threat or abuse was seen as more severe than verbal or social/emotional abuse, and professionals more often rated physical conflicts as bullying even when they did not fit the definition. The repeated nature of an abusive relationship and an unfair match between participants were bullying situation characteristics found to be related to the responses of more and less effective situation evaluators. Implications for pre- and in-service training of educators were considered based on study results and previous research. 相似文献
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During the early phases of research, semiparametric models (SPMs) have the advantage of recovering latent nonlinearity over parametric counterparts. Structural equation mixture models (Bauer, 2005) can be applied as SPMs to flexibly recover and describe the form of the unknown latent relationship with minimal distributional assumptions. This short report extends the work on this SPM (Bauer, 2005; Pek, Losardo & Bauer, 2011) by developing approximate simultaneous confidence bands or confidence envelopes (CEs) to evaluate potential nonlinearity of the unknown latent function. A line-finding algorithm to be used in conjunction with these CEs is also developed as an implementation of an informal test to diagnose nonlinearity. Coverage of the CEs and performance of the algorithm in terms of rates of detecting latent nonlinearity are evaluated by Monte Carlo. Recommendations for the use of these CEs and the algorithm for detecting nonlinearity are suggested. 相似文献
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Pek Leng NG Nor Fadilah RAJAB Sue Mian THEN Yasmin Anum MOHD YUSOF Wan Zurinah WAN NGAH Kar Yong PIN Mee Lee LOOI 《Journal of Zhejiang University. Science. B》2014,(8)
研究目的:探讨蒌叶(PB)提取物对5-氟尿嘧啶(5-FU)抑制结肠癌细胞HT29和HCT116生长的影响。研究方法:HT29和HCT116细胞分别给予PB、5-FU以及两种药物联合治疗24小时,应用等效线图法分析PB和5-FU的药效学相互作用,Annexin V/PI染色法检测HT29和HCT116细胞的凋亡情况,高效液相色谱法排除PB和5-FU间任何可能的相互化学作用。重要结论:联合PB,低剂量5-FU可以在短时间内起到细胞毒作用,而单独应用PB或5-FU治疗较联合治疗可以诱导更多细胞发生凋亡。进一步采用等效线图法分析显示PB和5-FU的联合作用在抑制结肠癌细胞HT29和HCT116的生长中分别体现出协同和拮抗作用。因此可以认为在HT29细胞中,PB使得较低剂量5-FU发挥最大抑制结肠癌细胞生长效果,然而在HCT116细胞中,PB没有显著降低5-FU的药物浓度,说明PB和5-FU的相互作用不仅仅体现在诱导细胞凋亡方面。 相似文献
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This paper presents the application of decision-theoretic technique to computer-based tutoring system for elementary mechanics. The technique uses sound probabilistic reasoning and a student model to identify learner's misconception(s). Bayesian belief networks are the building blocks of the student model. The probability values in Bayes' nets are provided by teacher and are based on her judgement, but may be substituted with actual statistics. Evidence on student's mastery of concepts is obtained through her responses to appropriately selected items. Subsequently, Rasch one-parameter model is used to calibrate the item and person parameters (also known as difficulty and ability indices, respectively). The system is able to provide teacher with information for fine-tuning her pedagogical instructions and guide her in coaching students. It is also able to provide students with immediate feedback to improve their proficiencies and ultimately their grades. 相似文献
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Craig A. Wrisberg Timothy P. Winter Jolynn S. Kuhlman 《Research quarterly for exercise and sport》2013,84(4):369-374
Abstract In the present study experimental subjects practiced variations in movement distance and/or movement time during training trials on a closed timing task. Control subjects trained with single distance-time combinations. During transfer trials all subjects attempted (without knowledge of results) a distance-time combination that was different (except in the case of one control condition) from any performed during training. The results revealed that the timing accuracy of the two experimental conditions that practiced a variety of times was significantly poorer than that of most of the other conditions during the training phase. However, transfer analyses revealed several significant differences between the performance of variable-trained and constant-trained conditions, in all cases favoring the former. It was concluded that the transfer benefits of variable practice are (a) not due to the particular movement component selected for variation during training, and (b) to some extent always determined by the similarity of training and transfer conditions experienced by constant-practice subjects. 相似文献
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Pek Leng NG ;Nor Fadilah RAJAB ;Sue Mian THEN ;Yasmin Anum MOHD YUSOF ;Wan Zurinah WAN NGAH ;Kar Yong PIN ;Mee Lee LOOI 《Journal of Zhejiang University. Science. B》2014,15(8):692-700
研究目的：探讨萎叶（PB）提取物对5-氟尿嘧啶（5-FU）抑制结肠癌细胞HT29和HCT116生长的影响。研究方法：HT29和HCT116细胞分别给予PB、5-FU以及两种药物联合治疗24小时,应用等效线图法分析PB和5-FU的药效学相互作用,AnnexinV／PI染色法检测HT29和HCT116细胞的凋丁L=情况,高效液相色谱法排除PB和5-FU间任何可能的相互化学作用。重要结论：联合PB,低剂量5-FU可以在短时间内起到细胞毒作用,而单独应用PB或5-FU治疗较联合治疗可以诱导更多细胞发生凋亡。进一步采用等效线图法分析显示PB和5-Fu的联合作用在抑制结肠癌细胞HT29和HCT116的生长中分别体现出协同和拮抗作用。因此可以认为在HT29细胞中,PB使得较低剂量5-FU发挥最大抑制结肠癌细胞生长效果,然而在HCT116细胞中,PB没有显著降低5-FU的药物浓度,说明PB和5-FU的相互作用不仅仅体现在诱导细胞凋亡方面。 相似文献
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