• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.945-953
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• 2010

This study was conducted to evaluate the effect of swine liquid manure (SLM) on rice grown in Yeonggwang-gun in 2008. The treatments consisted of SLM and chemical fertilizer (CF) based on the recommended amount of nitrogen (11 kg N $10a^{-1}$). The Total N content of the SLM used was 2,881 mg $L^{-1}$. Plant height at the early stage of growth and tiller number were not significantly different between plots applied with swine liquid manure and those with chemical fertilizer in all areas. Plant height at the later stage of growth, lodging and yield were not significantly different between plots applied with swine liquid manure and those with chemical fertilizer in three areas (Baeksu, Gunnam, Beopseong). Plant height at the later stage of growth, as well as lodging were higher in SLM plots than in chemically fertilized plots in Yeonggwang and Yeomsan. However, grain yield was lower in SLM plots than in chemically fertilized plots in these areas. Soil organic matter content and exchangeable cations increased in the swine liquid manure applied plots. Moreover, heavy metal content did not increase in the plots treated with swine liquid manure. Further research to determine the suitable rate of swine liquid manure is needed to reduce lodging damage and to increase the yield and quality of rice.

• Korean Journal of Psychosomatic Medicine
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• v.23 no.2
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• pp.93-99
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• 2015

Objectives : The purpose of this preliminary study was to investigate job stress and stress coping strategy among workers in a regional statistics office. Methods : A total of 133 workers in regional statistics office participated in this study and they were divided into two groups, survey group(n=109) and support group(n=24) depending on relation to statistical survey task. They were asked to respond to Short Form of Korean Occupational Stress Scale(KOSS-SF) and Stress Coping Strategy(SCS) to investigate sociodemographic characteristics, job stress, and stress coping strategy. Results : The proportion of the 133 participants in the sample was 59(44.4%) of men, 74(55.6%) of women. There were no significant differences in KOSS-SF scores in relation to age, sex, education, and marital status, while the KOSS-SF scores were significantly different between the two groups. In regard to the subscales of KOSS-SF, the two groups had significant differences in insufficient job control, interpersonal conflict, job insecurity, and organization system. In addition, the total score of KOSS-SF had a negative correlation with problem-focused coping strategy and social support coping strategy of SCS. Conclusions : Our results suggest that workers of survey group had more job stress compared to those who works in support group in regional statistical office. In addition, in comparison with workers of support group, both men and women of survey group get stressed when they were confronted with interpersonal conflicts. Our results suggest that using problem-focused coping and social support coping strategy lowers job stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.3
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• pp.248-255
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• 2021

This study was conducted to obtain basal information for the development of perilla cultivars with improved quality. The F₇ population of recombinant inbred lines (RILs) from a cross between the parents of Daesil for seeds and Ipdeulkkae1 for vegetables was used as the material. We evaluated several agricultural characteristics and seed quality. Variations were observed in most of the measurements; for example, stem length (ranging from 66.0 to 150.0 cm), number of branches (from 5 to 23), flower cluster length (ranging from 5.1 to 10.5 cm), number of flower clusters (from 17 to 131), a-linolenic acid content (from 54.2 to 64.1%), and functional compound content (rosmarinic acid 869.5~3,508.1 ㎍/g; luteolin 47.4~864.3 ㎍/g; apigenin 57.1~296.7 ㎍/g) all showed variation. Significant correlations between stem length and the number of branches (0.561) and number of branches versus number of flower clusters (0.638) were detected in the RIL F₇ population. Most agricultural characteristics and seed qualities showed a normal distribution with large variation, and transgressive segregation was observed in many descendants with characteristics to those of their parents. Daesil/Ipdeulkkae1 RIL F₇ populations could be useful for future QTL analysis as well as for intermediate breeding lines for high-quality perilla cultivars.

• Journal of Life Science
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• v.31 no.9
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• pp.840-848
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• 2021

This study was conducted to estimate annual trends and the environmental effects in the racing records of Jeju horses. The Korean Racing Authority (KRA) collected 48,645 observations for 2,167 Jeju horses from 2002 to 2019. Racing records were preprocessed to eliminate errors that occur during the data collection. Racing times were adjusted for comparison between race distances. A stepwise Akaike information criterion (AIC) variable selection method was applied to select appropriate environment variables affecting racing records. The annual improvement of the race time was -0.242 seconds. The model with the lowest AIC value was established when variables were selected in the following order: year, budam classification, jockey ranking, trainer ranking, track condition, weather, age, and gender. The most suitable model was constructed when the jockey ranking and age variables were considered as random effects. Our findings have potential for application as basic data when building models for evaluating genetic abilities of Jeju horses.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.387-393
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• 2021

In this study, finite element analysis was performed to evaluate a method of increasing the fatigue life of the pipe connection structure commonly used in the topside structure of offshore platforms. MSC Patran/Nastran, a commercial analysis program, was used, and the critical structural model was selected from the global analysis. To realize the stress concentration phenomenon according to the load, modeling using 8-node solid elements was implemented. The main loads were considered to be two lateral loads and a tensile load on a diagonal pipe. To check the hotspot stress at the main location, a 0.01 mm dummy shell element was applied. After calculating the main stress at the 0.5-t and 1.5-t locations, the stress generated in the weld was estimated through extrapolation. In some sections, this stress was observed to be below the fatigue life that should be satisfied, and reinforcement was required. For reinforcement, a bracket was added to reduce the stress concentration factor where the fatigue life was insufficient without changing the thickness or diameter of the previously designed pipe. Regarding the tensile load, the stress in the bracket toe increased by 23 %, whereas the stress inside and outside of the pipe, which was a problem, decreased by approximately 8 %. Regarding the flexural load, the stress at the bracket toe increased by 3 %, whereas the stress inside and outside of the pipe, which was also a problem, decreased by approximately 48 %. Owing to the new bracket reinforcement, the stress in the bracket toe increased, but the S-N curve itself was better than that of the pipe joint, so it was not a significant problem. The improvement method of fatigue life is expected to be useful; it can efficiently increase the fatigue life while minimizing changes to the initial design.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.630-647
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• 2021

We determined the current problem of the restoration deposit-estimation system, stipulated by the Mountainous Districts Management Act, using the Delphi technique. Consequently, we proposed a standard model for forest land restoration to derive a reasonable deposit-estimation system. With the result of the Delphi survey, the inappropriateness of land-use type and slope gradient classifications was shown; the insufficiency of standard works was a significant problem in the current system. A way to solve these problems was devised, to reorganize the current land-use type into the subject of the site. The specific subjects included the following: (i) to permit or report forest land-use change and temporary use of forest land, (ii) to report temporary use of forest land, (iii) to permit stone collection or sale for mineral mining, and (iv) to allow sediment collection. The current slope gradient subdivision into (a) θ<10°, (b) 10°≦θ<15°, (c) 15°≦θ<20°, (d) 20°≦θ<25°, (e) 25°≦θ<30°, and (f) θ≧30° and the reorganization of 17 standard works into 22 standard works were deemed as solutions, along with seven additional works. We developed 24 standard models for the forest land restoration project based on the aforementioned results. The deposits estimated by these models ranged from 34,185,000 (Korean) won to 607,403,000 won. If additional works, premiums, discounts, and supervision fees are added to the models, the deposit increases to an estimated 668,143,000 won subject to permission for stone collection or sale and mineral mining. Experts agree on the distribution of the restoration deposits estimated by these models at a high level in the Delphi survey. Our findings are expected to contribute to securing the appropriateness of the restoration cost deposited for the smooth performance of the vicariously executed restoration project.

• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1819-1827
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• 2021

Land-use/cover change caused by rapid urbanization in South Korea is one of the concerns in flood risk management because groundwater recharge by precipitation hardly occurs due to an increase in impermeable surfaces in urban areas. This study investigated the hydrologic effects of land-use/cover on groundwater recharge in the Yeonje-gu district of Busan, South Korea. A statistical time series analysis was conducted with temporal variations of precipitation and groundwater level to estimate lag-time based on correlation coefficients calculated from auto-correlation function (ACF), cross-correlation function (CCF), and moving average (MA) at five sites. Landform and land-use/cover within 250 m radius of the monitoring wells(GW01, GW02, GW03, GW04, and GW05) at five sites were identified by land cover and digital map using Arc-GIS software. Long lag-times (CCF: 42-71 days and MA: 148-161 days) were calculated at the sites covered by mainly impermeable surfaces(GW01, GW03, and GW05) while short lag-times(CCF: 4 days and MA: 67 days) were calculated at GW04 consisting of mainly permeable surfaces. The results suggest that lag-time would be one of the good indicators to evaluate the effects of land-use/cover on estimating groundwater recharge. The results of this study also provide guidance on the application of statistical time series analysis to environmentally important issues on creating an urban green space for natural groundwater recharge from precipitation in the city and developing a management plan for hydrological disaster prevention.

• Journal of Life Science
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• v.31 no.12
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• pp.1079-1087
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• 2021

To analyze gut microbiota of livestock in Korea and compare taxonomic differences, we conducted 16S rRNA metagenomic analysis through next-generation sequencing. Fecal samples from broiler chickens, pigs, and cattle were collected from domestic feedlots randomly. α-diversity results showed that significant differences in estimated species richness estimates (Chao1 and ACE, Abundance-based coverage estimators) and species richness index (OUTs, Operational taxonomic units) were identified among the three groups. However, NPShannon, Shannon, and Simpson indices revealed that abundance and evenness of the species were statistically significant only for poultry (broiler chickens) and mammals (pigs and cattle). Firmicutes was the most predominant phylum in the three groups of fecal samples. Linear discriminant (LDA) effect size (LEfSe) analysis was conducted to reveal the ranking order of abundant taxa in each of the fecal samples. A size-effect over 2.0 on the logarithmic LDA score was used as a discriminative functional biomarker. As shown by the fecal analysis at the genus level, broiler chickens were characterized by the presence of Weissella and Lactobacillus, as well as pigs were characterized by the presence of provetella and cattele were characterized by the presence of Acinetobacter. A permutational multivariate analysis of variance (PERMANOVA) showed that differences of microbial clusters among three groups were significant at the confidence level. (p=0.001). This study provides basic data that could be useful in future research on microorganisms associated with performance growth, as well as in studies on the livestock gut microbiome to increase productivity in the domestic livestock industry.

• Korean Journal of Community Nutrition
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• v.26 no.3
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• pp.167-176
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• 2021

Objectives: This study was conducted to identify the awareness and practice of reducing sugar in school meals and the status of nutrition education regarding sugar reduction. Methods: An online survey was conducted on 101 nutrition teachers (dietitians) working at elementary, middle, and high schools in Daegu. Results: School nutrition teachers in Daegu recognized the need for efforts to reduce the sugar intake in the Korean diet, and it was found that elementary nutrition teachers were more aware of the implementation of the sugar reduction policy at the national level than middle and high school nutrition teachers (P = 0.002). Among the policies to reduce sugar intake at the national level, there was a high need for the promotion of self-control and limiting the sales of food with high sugar content in schools and their vicinity. The degree of practice for reducing sugar in school meals was found to be higher in the preparation, purchase, and cooking stage compared to the serving stage (P < 0.05). There was a high need for changing the preferences of the subjects for a sweet taste as a means of reducing the sugar in school meals. Thirty-six percent of nutrition teachers conducted sugar reduction education, and sending out school newsletters was the highest type of nutrition education at 80.6%. Conclusions: To effectively promote reduced sugar intake in school meals, it is necessary to change the preference of the subjects for sweetness and to conduct continuous education that can improve the awareness of people for reducing their sugar intake. For this, it is necessary to set aside time for nutrition education and to prepare an institutional framework for providing this education.

• 한국노년학
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• v.38 no.4
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• pp.1083-1105
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• 2018

The present study sought to capture day-to-day fluctuation of the daily happiness among Korean urban older adults and to examine whether the within person fluctuation of daily happiness is explained by the social and physical activities the older adults experience each day. We also examined whether the within person association between daily social, physical activities and the daily happiness varies by individual characteristics(i.e. gender, age, educational level and health). In addition, we explored the relationships between the level and fluctuation of daily happiness and the level of global happiness. The data was collected by multi-method approach, which includes general survey, daily diary method and collection of physical activity data through the activity monitors. In total, 175 urban older adults participated for seven days of daily diary survey. The data about the number of steps and the time spent on sedentary activities, light intensity physical activities and moderate to vigorous intensity physical activities were also collected during the same period from 16 sub-samples using activity monitors. Hierarchical linear modeling was applied for the analysis. The results were as below. First, the level of happiness of older adults fluctuated during a week, and the patterns of fluctuation varied by the gender and the health. Second, socializing with their children and friends elevated their levels of happiness. Also the impact of contacts with siblings on the level of daily happiness was greater for the unhealthy group compare to the healthy group. Third, older adults were happier on the days when they walked more, but the level of daily happiness decreased on the days when they spent longer time for low intensity physical activities. Lastly, the higher level of daily happiness were related to the higher level of global happiness, but the degree of fluctuation of daily happiness was not related to the level of global happiness. The implications of these results and suggestions for future research are discussed.