• Journal of Environmental Health Sciences
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• v.41 no.4
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• pp.268-276
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• 2015

Objectives: According to the 2007 Korea National Environmental Health Survey (KNEHS), some areas in the Gyeongsang Provinces showed very high blood mercury levels in adults. We conducted this project to investigate any related health effects in children due to mercury levels in these areas. Methods: In total, 1,097 students between grades 3 and 6 at 19 elementary schools were recruited from four areas with high mercury exposure as identified by the KNEHS. Total mercury levels in biological samples were compared with health check-ups performed on the schoolchildren. Biological monitoring, supported by questionnaires, a computerized neurobehavioral test, a posturography test and a personality test, were applied. Results: Triglycerides showed a significant relation with mercury in blood, urine and hair. Total mercury concentrations were divided into two groups: upper and lower concentration groups based on the median value. In the computerized neurobehavioral test, the upper blood mercury group showed a greater reaction time for color-word vigilance (p<0.05). In the posturography test, the intensity value of the tremor test showd high significant relations with mercury levels (p<0.01). In the personality test, self-consciousness, misdeeds and family relationships showed significant differences between the upper and lower urine mercury groups (p<0.01), and specific reactions, ego resilience and hyperactivity also showed some differences (p<0.1). Conclusion: Some items in the neurobehavioral test, posturography test and personality test showed significant relations with biological mercury levels. Therefore, monitoring and appropriate management of students showing high mercury levels are recommended in order to reduce their mercury exposure.

• Journal of the Korean School Mathematics Society
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• v.18 no.1
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• pp.83-102
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• 2015

This study would suggest to analyze the perceptions of good mathematics teaching in high school and offer the resolutions for the conflicts caused by differences in perception between teachers and students in math class through previous studies and comparative implications. To this end, Students are classified by their courses, grades, gender awarenesses and they were analyzed and compared by the survey results. Although the preference for the math class that fixs the misconception of students is highest, regardless of the kinds of students groups. Academic students, middle-ranked students, female students have high affinity for the class to evaluate the material covered in class and take into account their level of assessment and instruction, low-ranked student's preference is higher for the class that has focused on understanding communicating their thinking processes than students. From this, it is suggested that academic students, low-ranked students are needed to be taught in a way that increases their confidence, interests, values and also in atmosphere that make math class a positive experience.

• Korean Journal of Health Education and Promotion
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• v.19 no.3
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• pp.121-133
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• 2002

The purpose of this study was to set up the basic model to monitor the health status of the middle and high school students in the adolescent period, as well as to provide the fundamental data which might serve as the new standards for their better health maintenance and promotion. The collected data comprised the characteristics of the subjects in the three different fields of life such as school, family and everyday, which could affect their physical fatigues, and they were analyzed to determine the factors of significant influence upon their physical fatigues and to reveal their relativity. A total of 5,954 students at 6 boys' and girls' middle and high schools in Taejon City completed self-administered questionnaires(to measure Health Practice Index and others) asking about each of three life domains during the period March through June, 2000. The key study results were as follows; 1. The middle school students showed more subjective symptoms of fatigue which may be a marker reflecting physical health status, than the high school students. The higher scores were associated, based on school life, with the groups who were boys, who were in lower school grades, who achieved better academic performances and had better relationship with friends. 2. As for family life, the higher scores were in the groups whose financial conditions were better, whose parents showed more interest to their children, whose sense of satisfaction with family life was higher, and whose health status was better. 3. As for life styles, the individuals showed the higher scores in the groups who had breakfasts daily, who didn't have inter-meal snacks, who took regular exercises, who didn't smoke and drink than, their counterparts. 4. The higher level of fatigue was associated with the groups whose health conditions were good, who are satisfied with school life, who were boys rather than girls, who are satisfied with family life, who didn't have inter-meal snacks, who were in good relationship with friends, who achieved greater academic performances, who took regular exercises, who didn't smoke, and whose parents showed more interest in their children.

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1031-1041
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• 2018

Objective: To compare image quality and radiation dose of high-pitch dual-source spiral cardiothoracic computed tomography (CT) between non-electrocardiography (ECG)-synchronized and prospectively ECG-triggered data acquisitions in young children with congenital heart disease. Materials and Methods: Eighty-six children (${\leq}3$ years) with congenital heart disease who underwent high-pitch dual-source spiral cardiothoracic CT were included in this retrospective study. They were divided into two groups (n = 43 for each; group 1 with non-ECG-synchronization and group 2 with prospective ECG triggering). Patient-related parameters, radiation dose, and image quality were compared between the two groups. Results: There were no significant differences in patient-related parameters including age, cross-sectional area, body density, and water-equivalent area between the two groups (p > 0.05). Regarding radiation dose parameters, only volume CT dose index values were significantly different between group 1 ($1.13{\pm}0.09mGy$) and group 2 ($1.07{\pm}0.12mGy$, p < 0.02). Among image quality parameters, significantly higher image noise ($3.8{\pm}0.7$ Hounsfield units [HU] vs. $3.3{\pm}0.6HU$, p < 0.001), significantly lower signal-to-noise ratio ($105.0{\pm}28.9$ vs. $134.1{\pm}44.4$, p = 0.001) and contrast-to-noise ratio ($84.5{\pm}27.2$ vs. $110.1{\pm}43.2$, p = 0.002), and significantly less diaphragm motion artifacts ($3.8{\pm}0.5$ vs. $3.7{\pm}0.4$, p < 0.04) were found in group 1 compared with group 2. Image quality grades of cardiac structures, coronary arteries, ascending aorta, pulmonary trunk, lung markings, and chest wall showed no significant difference between groups (p > 0.05). Conclusion: In high-pitch dual-source spiral pediatric cardiothoracic CT, additional ECG triggering does not substantially reduce motion artifacts in young children with congenital heart disease.

• Journal of the Korean Society of Food Culture
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• v.25 no.4
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• pp.400-409
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• 2010

This study investigated the food and dietary educational content in primary, middle and high school textbooks in order to provide fundamental data for the development of educational programs on Korean traditional food culture. The research objects consisted of 51 kinds of textbooks (15 kinds of primary school textbooks, 29 kinds of middle school home economics textbooks and 7 kinds of high school home economics textbooks), and the contents related to food and dietary education were counted and analyzed. The content analysis was performed using two categories: application method and subject matter. Application method included texts, cases, visual aids (pictures, photos, illustrations, chart, etc.) and activities, whereas subject matter consisted of seven types (well balanced nutrition and health, understanding of food and nutrition, cooking principles, cooking lessons, traditional foods and culture, others). The results of the application method in primary school textbooks show that visual aids were the most common in all six grades. For the subject matter, 'understanding of food and nutrition' was most abundant in primary school textbooks while 'well balanced nutrition and health' accounted for a large part of the contents in middle school textbooks. However, the contents regarding traditional foods and culture were insufficient in primary and middle school textbooks. These results suggest that educational contents on traditional foods and culture should be added to primary and middle school textbooks and covered in various subjects. Furthermore, high school 'home economics' contents need to emphasize comprehensive food and dietary education and adjust to 'science & technology for life'.

• Transactions of Materials Processing
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• v.33 no.2
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• pp.103-111
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• 2024

With the increasing global interest in carbon neutrality, the automotive industry is also transitioning to the production of eco-friendly cars, specifically electric vehicles. In order to achieve comparable driving distances to internal combustion engine vehicles, the application of high-capacity battery packs has led to an increase in vehicle weight. To achieve light-weighting and durability requirements of automotive components simultaneously, there is a demand for research on the application of Ultra-High Strength Steel (UHSS). However, when manufacturing chassis components using UHSS, there are challenges related to fracture defects due to lower elongation compared to regular steel sheets, as well as spring-back issues caused by high tensile strength. In this study, a simulated specimen that is not affected by the property changes of four materials was designed to improve formability of the rear cross member, which is the most challenging automotive chassis component. The influence and correlation of material-specific variables were analyzed through finite element analysis (FEA) for each material with tensile strength of 440, 590, 780, and 980 MPa grades, resulting in the development of a predictive equation. To validate the equation, the simulated specimens of 980 MPa grade were produced from the test molds. Then the reliability of the FEA and predictive equation was verified with measured specimen data using a 3D scanner. The results of this study can be proposed to improve the formability of UHSS chassis components in future researches.

• Research in Community and Public Health Nursing
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• v.8 no.2
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• pp.347-367
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• 1997

The purpose of this study was to investigate drug abuse and to find related factors among high school students. The subjects for this study were 973 students from 10 high schools in Taegu city. The data were collected from September 30, 1996 to October 30, 1996. The questionnaire developed by Kim Soyoaja (1991) surveyed adolescent drug use and questions on smoking and drinking were readjusted and added by the researcher based on review. The data was analyzed using frequency, percentage, $X^2-test$, t -test, Pearson Correlation Coefficient with the SPSS /PC+. The results of this study were summarized as follows: 1. The proportion of students who drank alcohol 1-2 times or more per year was 52.4% and smoked Cigarette 1 -2 times or more per year was 20.8%. The 7 different drugs(Analgetics 5.7%. sleeping pills and sedatives 4.2%, antihistamines 1.1%. stimulants 7.7%, hallucinogens 0.8%, inhalants 3.3%, and narcotics 0.6%) were also evaluated. 2. There was a significant relationship between drinking and type of school($X^2$=62.97, p<.0l), grades($X^2$=33.86, P<.001), school life($X^2$= 19.04, p<.001), and delinquent friends($X^2$= 64.72, P<.001). 3. There was a significant relationship between smoking and type of school($X^2$=153.65, p<.001), grades ($X^2$=67.53, p<.001), their respect for teachers ($X^2$=33.80, p<.001) school life($X^2$ =50.87, p<.001), and delinquent friends($X^2$ =85.28, p<.001). 4. There was a significant relationship between the 7 different kinds of drug abuse and type of school ($X^2$=14.65, p<.01), grades($X^2$=12.89, p<.01), their respect for teachers ($X^2$=8.46, p<.05), and delinquent friends($X^2$=22.42, p<.001). 5. There was a significant relationship between a parent's habitual drug abuse and the 7 different kinds of drug abuse($X^2$=7.78, p<.01), as well as a parent's attitude toward drugs and the 7 different kinds of drug abuse($X^2$=6.33, p<.05). 6. There was a significant difference between drinking(t=-12.53, p<.001), smoking(t=-15.98, p<.001), the 7 different kinds of drug abuse(t=-5.77, p<.001), and the respondant's delinquent experience. 7. There was a correlation between drinking and smoking(r=.4166, p<.001), drinking and the 7 different kinds of drug abuse(r=.2200, p<.001), smoking and the 7 different kinds of drug abuse(r=.1428, p<.05). There was a correlation between drinking and smoking(r=.5977, p<.001), drinking and the 7 different kinds of drug abuse(r=.2849, p<. 001), smoking and the 7 different kinds of drug abuse(r=.1711, p<.05) among male students. There was a correlation between drinking and smoking(r=.4219, p<.001), drinking and the 7 different kinds of drug abuse(r=.2611, p<.001), smoking and the 7 different kinds of drug abuse(r=.1764, p<.001) among female students. 8. There was a correlation between drinking and family stability(r=.0709, p<.05) drinkry and parent -child relationships (r=.1321, p<.01), drinking and mother's rearing attitude(r=.0704, P<.05), smoking and parent -child relationships(r=.0813, P<.05). There was a correlation between drinking and family stability(r=.14S7, p<.01), drinkng and parent-child relationships(r=.2147, p<.001), smoking and family stability(r=.1544, p<.01), smoking and parent. -child relationships (r=. 2018, P<.01) among male students. There was a correlation between drinking and family stability(r=.1l21, p<.05), drinking and mother's rearing attitude (r=.0988, P<.05), smoking and parent -child relationships (r=. 0940, P<.05) among female students. 9. There was a significant difference between the 7 different kinds of drug abuse and family stability (t=2.23, p<.05), parent-child relationships (t=4. 34, p<.001), satisfaction with family (t=4.02, p<.001), father's rearing attitude(t=3.04, p<.01), mother's rearing attitude(t=2.87, p<.01). The distribution channel of drugs including alcohol beverages and cigarettes should be evaluated and restructured to discourage student's temptation and to limit accessibility. The step by step preventive teaching on alcohol drinking and cigarette smoking is needed from middle school to help prevent further drug abuse.

• Journal of Korean Public Health Nursing
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• v.15 no.2
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• pp.285-300
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• 2001

In order to provide basic data for developing problematic drinking prevention program through the investigation of the knowledge and attitude on drinking of the elementary students, a survey was conducted covering 630 fourth, fifth, and sixth graders in 5 elementary schools, in Seoul. Data was collected by using structured questionnaire. The results of the survey analysis were as follows : 1. Among the students under inquiry, $55.4\%$ answered they had the experience of drinking and $1.9\%$ of them enjoy the drinking. 2. The degree of drinking-related knowledge of respondents were 8.41point with the highest score being 13. The score were significantly higher in the students with good school record and higher mothers' educational level than those of other group. 3. With respect to the attitude of students toward adults' drinking, $54.8\%$ responded that inebriated adults in the bus or subway cause inconvenience to others. Students who maintain good school grades, are satisfied with school lives, whose fathers have high educational background or who receive great attention from parents showed more negative and strict attitude toward adults' intoxicated appearance. Concerning the drinking at home, $51.6\%$ of respondents said they hope that adults do not drink at home. Students who have experience of drinking and whose parents drink revealed more generous attitude toward adults' drinking at home than those who do not. With regard to the drinking of friends or senior students, $55.0\%$ of students said they try to stop the drinking. Respondents with no experience of drinking were more generous toward the drinking of friends and colleagues than those who drank before. Students who are in low graded. maintain high school marks, face no problems in school life or receive great attention from parents demonstrated greater disapproval of drinking. Most respondents$(65.3\%)$ said they were not interested in the scene of drinking in mass media. Those having experience of drinking or parents who drink showed more tolerant attitude toward drinking in mass media than those who do not. Students who are in low grades, face many problems in school life or receive small attention from parents showed greater tendency to find the scene of drinking attractive. 4. The more knowledge they get, the more rigid view they had in drinking.

• Journal of The Korean Association For Science Education
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• v.31 no.5
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• pp.694-708
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• 2011

In this study, we developed tasks including cognitive scaffolding for students to explain scientific phenomena using valid evidences in science classroom and sought to investigate how tasks influence the development of small group scientific argumentation. Heterogeneous small groups in gender and achievement were organized in one classroom and the tasks were applied to the class. Students were asked to write down their own ideas, share individual ideas, and then choose the most plausible opinion in a group. One group was chosen for investigating the effect of tasks on the development of small group argumentation through the analysis of discourse transcripts of the group in 10 lessons, students' semi-structured interview, field note, and students' pre- and post argument tests. The discrepant argument examples were included in the tasks for students to refute an argument presenting evidences. Moreover, comparing opinion within the group and persuading others were included in the tasks to prompt small group argumentation. As a result, students' post-argument test grades were increased than pre-test grades, and they argued involving evidences and reasoning. The high level of arguments has appeared with high ratio of advanced utterances and lengthening of reasoning chain as lessons went on. Students had elaborate claims involving valid evidences and reasoning by reflective and critical thinking while discussing about the tasks. In addition, tasks which could have various warrants based on the data led to students' spontaneous participation. Therefore, this study has significance in understanding the context of developing small group argumentation, providing information about teaching and learning context prompting students to construct arguments in science inquiry lessons in middle school.

• Journal of Animal Science and Technology
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• v.51 no.1
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• pp.69-74
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• 2009

This study was carried out to investigate the carcass characteristics of crossbred pigs according to mating system, carcass grade and age at marketing. A total of 656 pigs of 128 gilts and 528 barrows were collected and analyzed at public slaughter house. Differences between LY and LYD crossbred on marbling score and water holding capacity were significantly (p<0.05) found. The influences of LY and LYD crossbred on carcass weight, backfat thickness, meat colour, carcass grade and age at marketing were not significantly showed. The carcass weight of D carcass grade was significantly (p<0.05) heavier than that of the other grade. The backfat thickness was significantly (p<0.05) appeared gradually in accordance with the increase of carcass grade. There was significantly difference among the carcass grades on water holding capacity (p<0.05). The differences among the carcass grades on the meat colour, marbling score and age at marketing were not found significantly. The carcass weight of high age group at marketing was significantly heavier than that of the low age group (p<0.05). The backfat thickness of the group of high age at marketing was significantly thicker than that of the group of low age (p<0.05). There were significant differences among age group at marketing in marbling score, carcass grade, and water holding capacity, respectively (p<0.05). The carcass weight was positively correlated with the backfat thickness but negatively correlated with the carcass grade. The correlation between the backfat and carcass grade was significantly negative. The meat colour was negatively correlated with water holding capacity.