A Longitudinal Analysis of Children’s Mathematical Word Problem Solving by Using Tablet PC-Based Support for the Metacognitive Skill Known as Self-Explanation

The purpose of the study was to examine the efficacy of self-explanation for helping elementary school children solve mathematical word problems through tablet PC-based support over one year and a half. Ninety-two fifth grade students received training and testing lasting into the sixth grade. The students solved worked-out examples for twenty minutes once a week in five two-week training sessions. They completed a word problem test at the end of each session. The results showed that all of the students gradually solved more word problems correctly after training than before. We classified students in the training condition into three groups according to the patterns of their test scores from an initial pretest and a first mathematical word problem test. Students in the upper group, who had consistently higher scores, appropriately generated a correct drawing and self-explanation of their solution processes and used inferences well. Some of the students in the middle group, who were gradually increasing their scores, also generated a correct drawing and self-explanation and used inferences well. Most students in the lower group, who had consistently low scores, did not generate a correct drawing and self-explanation and did not use inferences at first, but correctly drew inferences after receiving feedback. Self-explanation as a metacognitive skill is discussed

Rapid and Efficient Microwave-Assisted Synthesis of N-Carbamoyl-L-Amino Acids

A rapid and efficient method for the synthesis of N-carbamoyl-L-amino acids is reported. The procedure, involving the reaction between urea and alpha-amino acids sodium salts, was performed under microwave conditions using an unmodified domestic microwave oven. A careful study of the operative conditions indicated proline (1d) as the less reactive substrate and phenylglycine (1e) as the more reactive one among all the alpha-amino acids tested. Substitution of urea with potassium cyanate produced a low conversion into the corresponding N-carbamoyl derivative, and a possible explanation of this result is reported