• Journal of Ecology and Environment
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• v.35 no.2
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• pp.99-109
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• 2012

Litterfall dynamics in forests are assessed by estimating biomass production and decomposition. However, there have been few studies on how litter dynamics impact the health and management of ecosystems. Here, a new approach to measure and assess ecosystem function is presented based on conventional methods using littertraps, litterbags, and the mass on the forest floor. To assess the status of litter dynamics, the decay rate (k) was estimated from a litterbag experiment, and removal rates ($k_i$) were determined from mass balance on the forest floor at 21 sites on three mountains in South Korea. The $k_3$ (organic mass ratio of $O_i$ and $O_e+O_a$ + A horizons in November) values in an equilibrium state in South Korea were within the range of $k{\pm}0.174$ when considering the annual variation of litterfall production. This study also suggests that sampling sites for these types of studies should be in the middle, not at the ends, of steady slopes on the forest floor.

• International Journal of Human Ecology
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• v.6 no.1
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• pp.75-86
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• 2005

This study examines unique manifestations of intergenerational conflict related to the acculturation process of immigrant families. No scale that measured the acculturation aspect of intergenerational conflict exsited. Thus, a new scale was developed to investigate this unique aspect among Korean American adolescents. The study design was cross-sectional, and employed a convenience sampling method. The participants were Korean American adolescents of junior and senior high school age, 14 to18 years old. The study was conducted at eleven Korean churches and one hakwon (private out-of-school studies .institute) in Fairfax County, Virginia. Korean American adolescents expressed that the issues related to education, such as academic pressures and high expectations, caused intergenerational conflict most frequently. Unlike findings from previous studies, the participants indicated that language differences between parents and children rarely caused intergenerational conflict. Contrary to previous findings, none of the characteristics variables, such as age, gender, length of residency and language preference, were significantly correlated with this unique conflict. This study provides a rare opportunity to enhance our understanding on how Korean American adolescents interact with their immigrant parents.

• Korean Journal of Child Studies
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• v.15 no.2
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• pp.37-54
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• 1994

The home environments, daily activities, caregiving behaviors of mothers and teachers, infant's verbal behaviors, attachment to mothers and teachers of day care infants were compared to those of home-reared infants. 30 two-year-old home-reared infants and their mothers were observed at home by the time sampling method and 31 two-year-old day care infants and their mothers and teachers were observed at home or at the center. The HOME scale, the behavioral checking lists for caregiving behaviors and for the infants' verbal behaviors, and the Attachment Q-set were used for the home and center observations. It was found that the characteristics of early environments of day care infants were different from those of home-reared infants, but that infants' attachment to the mothers were not different. However, day care infants' attachment security scores to their mothers were higher than to their teachers.

• Journal of Environmental Health Sciences
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• v.35 no.4
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• pp.239-248
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• 2009

The Institute of Medicine of the National Academies of Science in the United States concluded in its 2004 report that excessive indoor dampness is a public health hazard and that its prevention should be a public health goal. Water damage in buildings, such as leaks from roofs, walls, or windows, may increase indoor moisture levels. Excessive dampness may promote microbial proliferation in indoor environments, increase occupants' exposure to microbial agents, and eventually produce adverse health effects in building occupants. Epidemiological studies to demonstrate the causal association between exposure to indoor microbial agents and health effects require reliable exposure assessment tools. In this review, I discuss various sampling and analytical methods to assess human exposure to biological agents in indoor environments, their strengths and weaknesses, and recent trends in research and practice in the USA.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1203-1208
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• 2001

Linzhi Native Pig is a unique local breed recently discovered in the hinterland of Tibet. Its geological distribution, natural environment and ecological conditions have been explored. Using random sampling in typical colony of classification and standard animal-scientific and biogenetic techniques, we examined its contour features, size and weight, reproductive performances, carcass characters, meat quality, fresh-keeping features and the frequency distribution in the 19 structural gene loci encoding enzymes and proteins; according to folklores and Tibetan, Chinese and English history books, the materials and literature of Tibetan Studies, we have analyzed its origin and affirmed the fact that its products have been consumed as Tibetan medicine resources. Our findings make certain that Linzhi Native Pig holds great potential value in economy and culture.

• The Korean Journal of Applied Statistics
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• v.25 no.4
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• pp.681-695
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• 2012

In this paper, a family of estimators for the finite population variance investigated by Srivastava and Jhajj (1980) is studied under two different situations of random non-response considered by Tracy and Osahan (1994). Asymptotic expressions for the biases and mean squared errors of members of the proposed family are obtained; in addition, an asymptotic optimum estimator(AOE) is also identified. Estimators suggested by Singh and Joarder (1998) are shown to be members of the proposed family. A correction to the Singh and Joarder (1998) results is also presented.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.815-822
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• 2016

The cationic biopolymer chitosan has several applications in medicine. Chitosan is the deacetylated derivative of chitin, the second most abundant naturally occurring polymer. Recent studies have investigated the relationship between chitosan and antibacterial activity. However, the molecular interactions and mechanisms have not been detailed. This study used molecular dynamics simulations to study interactions between chitosan and anionic bacterial membranes (POPE-POPG) and electrically neutral non-bacterial membranes (POPC). We calculated the free energy using umbrella sampling to compare the interactions between membranes and chitosan in different protonation states. Fully protonated chitosan interacted most strongly with the bacterial membranes, but weakly with non-bacterial membranes. These results suggest that electrostatic interactions are the main mechanism of the antibacterial activity of chitosan, and they provide insights into the design of novel antibacterial and antimicrobial agents.

• Korean Journal of Child Studies
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• v.17 no.2
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• pp.121-139
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• 1996

The purpose of the present study was to explore a model program to improve preschool children's self-concept, perspective-taking and prosocial behavior through "Understanding Activities of Self and Others." Sixty 5- to 6-year-old children were selected by random sampling from a Kindergarten located in Seoul. Thirty children were in the experimental group and 30 were in the control group. The 8-week intervention program used the instrument, "Understanding Activities of Self and Others," constructed by the present researchers. One-way ANOVA and MANOVA were used for data analysis. At the end of the 8-week period, significant differences were found between the experimental and control groups in self-concept, perspective-taking ability, and prosocial behavior. This indicates the effectiveness of the present study in improving children's affective, cognitive, and behavioral traits.

• Korean Journal of Child Studies
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• v.25 no.6
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• pp.225-240
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• 2004

Subjects were 15 teachers and 143 children at 15 child-care centers in Seoul that varied by quality of care. The Child Care Program Observation Scale(Rhee et at., 2003) was employed to observe the quality of the centers. Information on teachers' participation in play was collected by 20 units of observation for each teacher using a rating scale developed by the author. Children's behaviors were observed with time sampling method in 12 categories of play behaviors based on Social and Cognitive Play Scales(Rubin et al., 1978). Children's play behaviors varied by quality of child-care centers and teachers' participation in play. When child-care quality was high, teachers' participated actively in children's play and children showed developmentally appropriate play behaviors.

• Korea journal of population studies
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• v.5 no.1
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• pp.99-116
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• 1982

The historical study reveals that our ancestors had maintained a system which could produce data on population and households. The main purposes of maintaing the system at that time were taxation and conscription. At the present time, however, there are three major data sources which produce the statistics on pop-ulation and households in Korea : Civil Registration System, Resident Registration System and Popula-tion Census. These three systems are found to have some problems. there are some inherent problems in the regis-tration systems, such as problems in its coverage, accuracies in contents and timeliness in reporting the vital events and publishing the results. The population census has also non- sampling erors, such as errors in coverage, respone and non-response. Apart from the above mentioned problems, there are also conflicting problems arised from having three data sources, We can find some overlapping problems and difficulties in comparative studies. In the future, these problems should be considered for the improvement of the quality of statistics on population and household.