A Comparative Study on the Instructional Models about the Concept of Economic System

The present study aims two parallel goals: to compare the effectiveness of three strategies for teaching the concept of economic system and to make some meaningful suggestions on the teaching of concepts in social studies. To be concrete, two main questions to be answered are as follows: First, What are the characteristics of teaching the concept of economic system?" Second, Which is the most appropriate instructional model considering the given characteristics?" To answer these questions, three experimental groups-attribute model, prototype model, social context model-are compared, with the control group using the conventional approach. The sample consists of 170 second-grade junior high school boys. The treatment for all groups is carried out over 2 weeks. The instrument used in the study is the economic system concept formation test. One-way ANOVA (four treatment conditions including a control group) results in significant effects. The results indicate that (a) the attribute model, the prototype model, and the social context model produce a significant greater test score than that of the conventional approach, and that (b) the social context model produces a significant greater test score than those of the others. As the implications of teaching the economic concept, this study suggests that (a) in teaching economic concept, the social context-centered approach is a good thing, and that (b) the consideration of epistemological characteristics of a concept is able to contribute greatly to a good concept-learning. Through this study, especially, we find that the characteristics of the concepts in social studies topics playa decisive role in the determination of the instructional model. This study will contribute to the improvement of the learning and instruction in a Korean economics lesson and make a new attempt at the instructional research

Situs Inversus Viscerum Totalis, Accompanied by Tetralogy of Fallot, Localized Endocardial Fibrosis, and Nephrosclerosis with Hypertension

to have situs inversus totalis including dextrocardia. and tetralogy of Fallot. A surgical palliation was tried, but it was found to be of little avail. Post-mortem examination revealed the following: All thoraco-abdominal viscera and vessels were in the mirror-image position of the normal. The heart was in the right hemithorax in the mirror -irnage position of the normal, the cardiac axis directing right-lateralwards. The heart was globular in shape, enormously large, and weighed 500 gms. On section, the heart revealed tetralogy of Fallot in dextrocardiac position, including marked pulmonary stenosis of infundibular type with hypoplasia of pulmonary artery, marked hypertrophy of left-sided right ventricle (venous ventricle), large interventricular septal defect at the pars membranacea, and sinistroposition and over-riding of the aorta. There was a large 6X3cm. localized elongatedrhomboid area of endocardial thickening in the rightsided left ventricle(arterial ventricle), that revealed microscopically markedly increased noninflamed loose 171 fibrous connective tissue with some elastic fibers extending into the adjacent and underlying myocardium. Multiple small fenestration of the aortic valve leaflets and marked dil-atation of bilateral bronchial arteries in the mirror image position were observed. An aberrant parathyroid gland was observed over the trachea, 1.5 em. distal to the right lower pole of the thyroid gland. The right and left kidneys weighed 120 gms, and 100 gms, respectively, and showed bilateral diffuse but mild arteriolar nephrosclerosis. Clinically this patient had mild hypertension. The aorta and its main branches showed marked atherosclerosis. There were moderate generalized passive congestion of all viscera and clubbed fingers and toes. A small confluent nodular lesion of fibrocaseous tuberculosis that was partly calcified was observed in the right upper lobe of the lungs. This is believed to be the first autopsy case of congenital anomaly of the heart of this type reported in the Korean literature