Learning and Verbal Communication     

David Sless 《The International Journal of Art & Design Education》1983,2(3):357-360

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Professionalizing the role of “truth-seekers”     

David Hogan  Clarence Karier 《Interchange》1978,9(2):45-71

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Synthetic and biological studies on a cyclopolypeptide of plant origin     

Dahiya R  Kumar A 《Journal of Zhejiang University. Science. B》2008,9(5):391-400

Objective: A natural cyclic peptide previously isolated from Citrus medica was synthesized by coupling oftetrapep-tide units Boc-Leu-Pro-Trp-Leu-Ome and Boc-Ile-Ala-Ala-Gly-Ome after proper deprotection at carboxyl and amino terminals followed by cyclization of linear octapeptide segment.Methods: Solution phase technique was adopted for the synthesis of cyclooctapeptide--sarcodactylamide.Required tetrapeptide units were prepared by coupling of Boc-protected dipeptides viz.Boc-Leu-Pro-OH and Boc-Ile-Ala-OH with respective dipeptide methyl esters Trp-Leu-Ome and Ala-Gly-Ome.Cyclization of linear octapeptide unit was done by p-nitrophenyl ester method.The structure of synthesized cyclopolypeptide was elucidated by FTIR,1H NMR,13C NMR,FABMS spectral data and elemental analysis.The newly synthesized peptide was evaluated for dif-ferent pharmacological activities including antimicrobial,anthelmintic and cytotoxic activities.Results: Synthesis of sarcodac-tylamide was accomplished with >78% yield utilizing dicyclohexylcarbodiimide (DCC) as coupling agent.Newly synthesized peptide possessed potent cytotoxic activity against Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines,in addition to moderate anthelmintic activity against earthworms Megascoplex konkanensis,Pontoscotex corethruses and Eudrilus sp.Moreover,cyclopolypeptide displayed good antimicrobial activity against pathogenic fungi Candida albicans and Gram-negative bacteria Pseudomonas aeruginosa,in comparison to standard drugs griseofulvin and ciprofloxacin.Conclusion: Solution phase technique employing DCC and triethylamine (TEA) as base proved to be effective for the synthesis of natural cyclooctapeptide.N-methyl morpholine (NMM) was found to be a better base for the cyclization of linear octapeptide unit in comparison to TEA and pyridine.  相似文献   

Designing Curriculum-Based Mathematics Professional Development for Kindergarten Teachers     

Drew Polly  Christie S. Martin  Jennifer R. McGee  Chuang Wang  Richard G. Lambert  David K. Pugalee 《Early Childhood Education Journal》2017,45(5):659-669

This study examines the influence of a year-long mathematics professional development program on Kindergarten teachers’ beliefs, content knowledge, instructional practices, and their students’ achievement. The professional development program is grounded in the theoretical construct of learner-centered professional development and focuses on supporting teachers’ integration of standards-based pedagogies aligned with the Common Core State Standards in Mathematics. Data analysis included examining 15 Kindergarten teachers’ mathematics content knowledge, their beliefs about mathematics, their enactment of student-centered pedagogies, and student achievement on curriculum-based assessments. Findings indicated that teachers adopted more student-centered pedagogies and embraced more student-centered beliefs about mathematics teaching during their time in the project. Further, Kindergarten teachers also demonstrated gains in their mathematical content knowledge, and those content knowledge gains were linked to gains in student achievement.  相似文献   

Adult Education in Suisse Romande     

David Matheson 《Compare》1995,25(2):115-135

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The Roles of Parental Support and Family Stress in Adolescent Sleep          下载免费PDF全文

Kim M. Tsai  Ronald E. Dahl  Michael R. Irwin  Julienne E. Bower  Heather McCreath  Teresa E. Seeman  David M. Almeida  Andrew J. Fuligni 《Child development》2018,89(5):1577-1588

The current study examines the association between parental support and adolescent sleep under varying levels of family stress. Participants included 316 adolescents (M_age = 16.40 years, 43% male) and their parents (M_age = 45.67 years, 91% mothers) from diverse ethnic backgrounds. Both adolescents and parents completed questionnaires and adolescents wore wrist actigraphs and completed self‐reports on their sleep for 7 consecutive days. Results indicated that under contexts of family stress, more parental support was linked to longer sleep duration, less sleep variability, and less time spent awake during the night. Findings suggest that under contexts of family stress, cohesive family relationships may provide a sense of stability and security that is necessary for healthful sleep.  相似文献   

Book review     

David Wheeler 《Educational Studies in Mathematics》1996,31(3):339-348

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Evaluating students' misconceptions by means of diagnostic multiple choice items     

David Treagust 《Research in Science Education》1986,16(1):199-207

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Comparing Models of Change to Estimate the Mediated Effect in the Pretest–Posttest Control Group Design     

Matthew J. Valente  David P. MacKinnon 《Structural equation modeling》2017,24(3):428-450

Models to assess mediation in the pretest–posttest control group design are understudied in the behavioral sciences even though it is the design of choice for evaluating experimental manipulations. The article provides analytical comparisons of the four most commonly used models to estimate the mediated effect in this design: analysis of covariance (ANCOVA), difference score, residualized change score, and cross-sectional model. Each of these models is fitted using a latent change score specification and a simulation study assessed bias, Type I error, power, and confidence interval coverage of the four models. All but the ANCOVA model make stringent assumptions about the stability and cross-lagged relations of the mediator and outcome that might not be plausible in real-world applications. When these assumptions do not hold, Type I error and statistical power results suggest that only the ANCOVA model has good performance. The four models are applied to an empirical example.  相似文献   

Avoiding Bias in Randomised Controlled Trials in Educational Research   总被引：1，自引：0，他引：1  

David J. Torgerson  & Carole J. Torgerson 《British Journal of Educational Studies》2003,51(1):36-45

Randomised controlled trials (RCTs) are often seen as the 'gold standard' of evaluative research. However, whilst randomisation will ensure comparable groups, trials are still vulnerable to a range of biases that can undermine their internal validity. In this paper we describe a number of common threats to the internal validity of RCTs and methods of countering them. We highlight a number of examples from randomised trials in education and health care where problems of execution and analysis of the RCT has undermined their internal validity. However, awareness of these potential biases can lead to careful planning to avoid or reduce their occurrence. If good quality randomised trials are to inform policy and practice in education then rigorous trials need to be designed that are the least susceptible to threats to their validity.  相似文献