• Journal of Preventive Medicine and Public Health
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• v.54 no.1
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• pp.37-45
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• 2021

Objectives: Bisphenol A (BPA) is used in the electrical, mechanical, medical, and food industries. Previous studies have suggested that BPA is an endocrine disruptor. Regulation of BPA has led to increased use of bisphenol F (BPF) and bisphenol S (BPS). However, few studies have investigated the associations of BPF and BPS with thyroid dysfunction in children. Our study investigated the associations of prenatal BPA and early childhood BPA, BPF, and BPS exposure with thyroid function in 6-year-old children. Methods: Prenatal BPA concentrations were measured during the second trimester of pregnancy in an established prospective birth cohort. We measured urinary BPA, BPF, and BPS concentrations and thyroid hormone levels (thyroid-stimulating hormone, total T3, and free T4) in 6-year-old children (n=574). We examined the associations between urinary bisphenol concentrations and percentage change of thyroid hormone concentrations using multivariate linear regression. We also compared thyroid hormone levels by dividing the cohort according to BPA, BPF, and BPS concentrations. Results: The associations between prenatal BPA and total T3 levels were statistically significant in all models, except for girls when using a crude model. The associations between urinary BPA and BPS concentrations and levels of all thyroid hormones were not statistically significant. However, we observed that lower free T4 levels (-1.94%; 95% confidence interval, -3.82 to -0.03) were associated with higher urinary BPF concentrations in girls only. Conclusions: Our findings identified significant associations between prenatal BPA exposure and total T3 levels in all children and between BPF exposure and free T4 levels in girls only.

• Korean Journal of Child Studies
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• v.19 no.2
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• pp.147-157
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• 1998

The purpose of this study was to investigate children's ideas about self-regulation in such situational variables as the presence of explicit rules and the domains of social rules. The subjects were 6-, 9-, and 12-year-old children (344). To assess children's ideas about self-regulation, a procedure was devised in which children were presented with stories portraying a protagonist in a conflict between an implicit or an explicit rule and a personal desire. The children were asked to make a choice for the protagonist and to give reasons for their choice. Major findings as follows: (1) There was significant difference in children's self-regulation depending on the presence of explicit rules. (2) There was significant difference in children's self-regulation depending on the domains of social rules. In situations that involved no explicit rules for behaviors, there were significant differences depending on the domains. In situations that involved explicit rules for behaviors, for 6- and 9-year-old children, there was no significant difference depending on the domains. (3) Children's use of justifications for their choice of action varied as a function of the characteristics of the social rules.

• Phonetics and Speech Sciences
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• v.7 no.1
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• pp.57-65
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• 2015

This study aimed to identify the development pattern of final stop consonant perception using the gating task. Sixty-four subjects participated in the study: 16 children aged 4 years, 16 children aged 5 years, 17 children aged 6 years, and 15 adults. One-syllable words with consonant-vowel-consonant(CVC) structure, mokㄱ-motㄱ and papㄱ-patㄱ were used as stimuli in order to remove the redundancy of acoustic cues in stimulus words, 40ms-length (-40ms) and 60ms-length (-60ms) from the entire duration of the final consonant were deleted. Three conditions (the whole word segment, -40ms, -60ms) were used for this speech perception experiment. 48 tokens (4 stimuli ${\times}3$ conditions ${\times}4$ trials) in total were provided for participants. The results indicated that 5 and 6 year olds showed final consonant perception similar to adults in stimuli, papㄱ-patㄱ and only the 6-year-old children showed perception similar to adults in stimuli, 'mokㄱ-motㄱ. The results suggested that younger typically developing children require more acoustic information to accurately perceive final consonants than older children and adults. Final consonant perception ability may become adult-like around 6 years old. The study provides fundamental data on the development pattern of speech perception in normal developing children, which can be used to compare to those of children with communication disorders.

• MALSORI
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• no.52
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• pp.85-99
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• 2004

The aim of this study is to show developmental characteristics of vocabulary of Korean children. In this study, words were classified according to the origin of words: pure Korean, sino-Korean and foreign words. The results of the present study are as follows: In common nouns, the rate of sino-Korean was 33.6% in 3 year-old children but 50.7% in 8 year-old children. Adverb and prenouns showed the similar rate. The rate of words with foreign origin was 10 ～ 11 % in all age groups.

• Korean Journal of Childcare and Education
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• v.16 no.5
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• pp.1-26
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• 2020

Objective: This study investigated 5-year-old children's developmental levels for creative and social personalities according to gender, and whether participation in STEAM-based unplugged robotic activities can improve their creative and social personalities. Methods: Participants were 5-year-old children (N=125) from 11 child care centers. The experimental group included 29 boys and 24 girls enrolled in classrooms that implemented an unplugged activities curriculum over five weeks. The control group consisted of 38 boys and 34 girls. Data were analyzed using a t-test and analysis of covariance, and Hedges' g was used to measure effect size. Results: First, the participating children's mean scores on creative and social personalities were 3.20 and 3.53 on a 5-point Likert scale, respectively. Girls scored higher than boys in sensitivity-various interests and imagination-playfulness domains of creative personality and all three domains of social personality. Second, children in the experimental group showed improvement in all domains of social personality and the effect size was large. They also improved in three domains (openness-humor, imagination-playfulness, independency-immersion) of creative personality, although the effect size was small. Conclusion/Implications: The results imply that implementing a robotics curriculum with unplugged play activities in early childhood classrooms contributes to 5-year-old children's development of creative and social personalities.

• Korean Journal of Childcare and Education
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• v.9 no.6
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• pp.339-368
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• 2013

This study aims to discover how three-year-old children to search for existence and its meaning, while they participate a programme, 'discourse among children through books' as a way of resolving curiosities. Data were collected between April 2, September 10, 2010 and the collected data included teacher's class records, pictures, discussion notes and interview materials. The results showed that 'discourse among children through books' follows steps in a process. The steps include: Deciding a topic that children should search for, choosing an appropriate book to resolve children's curiosities, spending some time for discoursing among children by using pictures in the book, and sharing what they had understood. Through this process, a pre-school teacher met with children who were full of abilities, ideas and motivation to explore with a little assistance. The pre-school teacher was able to overcome preconceived ideas that informational books could be difficult for children, and experienced various lessons, while the children led their own learning. It represents that the activity, 'discourse among children through books' can be a children centered inquiry learning teaching strategy, because the informational books ensure that the children gain knowledge and are actively in cogitation.

• International Journal of Human Ecology
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• v.12 no.1
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• pp.15-24
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• 2011

This study investigated childhood eating behavior, the influence of eating behavior on the positive and negative emotionality of children, and the pattern or eating behavior influence on emotionality depending on the age and gender of children. A total of 202 children (ages 5 to 7) were selected from 3 nurseries and 1 kindergarten ill Seoul and the survey data responses from teachers were analyzed. The results were as follows. First, children with higher levels of eating behavior showed a higher positive emotionality score compared to those with lower levels of eating behavior. The effect of gender was not significant and positive emotionality tended to increase in the 5 and 6 year old groups as the level of eating behavior increased; in addition, it was generally similar in the 7 year old group. Second, the children with lower level, of eating behavior showed a higher negative emotionality score compared to those with higher levels of eating behavior. The main effects by age and gender were insignificant; however, the interaction of age and eating behavior affected the negative emotionality of children. The eating behavior of children affects emotionality and children with better eating behaviors showed more positive emotional responses and less negative emotional responses in the same circumstances.

• Journal of the Korean Home Economics Association
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• v.40 no.5
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• pp.39-51
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• 2002

The purpose of this study is to investigate prior thinking and posterior thinking formation of children and adolescents in sinking objects. The subjects consisted of twenty eight, 9- and 11-year old children and fourteen, 13-year old adolescents selected from one elementary school and two middle schools. The transcripts were analyzed to classify children and adolescents'prior thinking and posterior thinking frequency, reasoning response(evidence based response, idea based response) and reasoning method(valid method, invalid method). The data were analyzed by frequency, percentile, mean and standard deviation,1 test, ANOVA. Major findings were as followings: 1. Children and adolescents have already had prior thinking in sinking objects. 2. Children and adolescents applies their prior thinking to posterior thinking formation process. 3. There were significant differences in children and adolescent'posterior thinking formation process, especially choices in objects and reasoning methods depending on age. 4. There were significant differences in children and adolescents'reasoning response depending on presented evidences types.5. Through the experimentation, children and adolescents'prior thinking was different from their posterior thinking. There were significant differences in differences between the prior thinking and posterior thinking depending on age.

• Korean Journal of Child Studies
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• v.30 no.4
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• pp.69-85
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• 2009

The purpose of this study was to identify developmental trajectories of externalizing problems in preschoolers and to investigate dimensions of temperament and parental behaviors associated with trajectory groups. Subjects were 180 3- to 5-year-old preschoolers (96 males, 84 females) in the metropolitan area of Seoul. They were assessed three times at 5 month intervals over a one year period. Teachers reported on children's behavior problems, and parents reported on children's temperaments. Latent Growth Curve Modeling Analysis with cohort sequential design revealed externalizing behaviors gradually decreased between 3 and 6. At the 6-year-old level externalizing behaviors were associated with high novelty seeking temperament. The results were discussed in terms of the importance of longitudinal research in developmental psychopathology.

• Speech Sciences
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• v.12 no.4
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• pp.183-195
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• 2005

In the present study, we investigated development of verb inflections or endings in 3- to 5-year old Korean-speaking children using 28 action verbs for both comprehension and production tasks. For each verb, a l0-second long motion picture and a sheet of paper with three random-ordered color pictures representing 'before, in the middle of, at the end of' the action were generated. A past tense inflection' -et ta,' two present progressive verb endings '-enta' & '-ko itta.' a future tense ending '-elyeko hanta' were tested. In the comprehension task, children were asked to point to a picture correctly representing the tense of a presented verb. In the production task, children were asked to produce a verb with correctly marking the tense of a presented picture. The order of the two tasks were counterbalanced across the children, and the motion pictures were only presented in the first task. Across the ages, the performance accuracies on both comprehension and production tasks were the highest for the past tense marking followed by two present progressive and future tense markings. For each verb endings, the changes of accuracies across ages were analyzed in both tasks. The types of errors for production tasks were also reported.