• Toxicological Research
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• v.32 no.4
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• pp.327-335
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• 2016

This study aimed to evaluate the potential toxicity and safety of ethyl hydrogen adipate (EHA) by determining its effect on the reproductive function and development of Sprague-Dawley (SD) rats at dose levels of 0 (control), 200, 400, and 800 mg/kg/day. One male and five females of the 800 mg/kg/day died. Body weight loss was observed in the males of the 800 mg/kg/day and in females of the 400 and 800 mg/kg/day. In addition, mating indices decreased and pre-implantation loss rates increased in parental animals of the 400 and 800 mg/kg/day. The gestation index decreased in the male and female rats of the 800 mg/kg/day. Moreover, the body weight of the pups from the 800 mg/kg/day group decreased on post-parturition day 4. These results indicated that the no-observed-adverse-effect level of EHA for parental males and females was 400 mg/kg/day and 200 mg/kg/day, respectively, and that for pups was 400 mg/kg/day.

• Development and Reproduction
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• v.21 no.1
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• pp.79-91
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• 2017

The aim of this study was to compare the efficacy of cryopreservation methods for ex situ conservation of spermatozoa from far eastern catfish, Silurus asotus. The spermatozoa activity index (SAI) and hatching rates were higher in spermatozoa stored in Alserver's solution than those of spermatozoa stored in glucose solution. The SAI and hatching rates in all experimental groups gradually decreased with increasing duration of storage. Additionally, the SAI and hatching rates gradually decreased with increasing thawing temperatures at all storage durations (P<0.05). Based on the SAI and hatching rates, our results suggest that the optimal cryopreservation conditions of catfish spermatozoa involve storage in Alserver's solution with 15% ethylene glycol, and thawing at $25^{\circ}C$. Cryopreservation of spermatozoa is a useful and reliable technique for conserving gene resources and for artificial propagation of far eastern catfish.

• Development and Reproduction
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• v.21 no.2
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• pp.223-228
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• 2017

This study investigated the effect of different photoperiods (14L: 10D, 12L:12D and 10L:14D) on the gonadal development and GtH mRNA expression in the pituitary of damselfish. The results showed that gonadosomatic index (GSI) was significantly lower in shot photoperiod (10L:14D), in comparison with other photoperiodic group during the spawning season. After 60 days treatment, histological analysis of gonad tissue showed that the gonad of 10L:14D and 12L: 12D treatment groups were resting phase with spermatogonia and perinucleolus stage oocytes but the gonad of 14L:10D treatment group was still ripe phase with spermatozoa and mature stage oocyte. The $FSH{\beta}$ and $LH{\beta}$ mRNA expression in pituitary drastically decreased shot photoperiod treatment from July (spawning period). These results suggest that photoperiod is considered to be the most effective environmental factor in controlling the reproductive cycle of damselfish.

• Journal of Environmental Impact Assessment
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• v.13 no.6
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• pp.307-314
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• 2004

Among large developmental projects, those of the government and public institutions with the total budget of more than 50billion wons can be executed only when the feasibility of the project has been testified through the procedure of preliminary feasibility study. Multi-purpose dams are public structures that can supply water, produce electricity, and control flood, they belong to large national projects that require legal evaluation procedures such as preliminary feasibility study and environmental impact assessment(EIA). The index that should be considered to be important in dam plan is the migration of residents in submerged district. The importance in the preliminary feasibility study is 4.93 points(98.6 in the scale of 100 at maximum). Among the 12 assessment elements of the policy and economy in the preliminary feasibility study, the element of environment assessment is turned out to be 4.68 points in the assessment importance (93.5 in the scale of 100 at maximum), which is the second in the total ranking and the first in the field of policy, indicating that the element is very important in dam construction planning.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.6
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• pp.554-558
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• 2000

Reproductive biology of the female red tongue sole, Cynoglossus joyneri was investigated by means of histological methods. Gonadosomatic index (GSI) was the highest in June. Developmental pattern of oocytes was group-synchronous. Egg stalk and yolk nucleus were observed in the early growing oocytes. Reproductive cycle could be classified into the growing ($February{\~}May$), maturation ($May{\~}June$), ripe and spent ($June{\~}August$), and recovery and resting ($August{\~}February$). The absolute fecundity per individual ($TL 28.1{\~}30.8 cm$) was 2,197 and relative fecundity per g body weight was 18.0.

• Agribusiness and Information Management
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• v.11 no.1
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• pp.1-9
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• 2019

This research intends to propose the methodology for analyzing the current trends of agriculture, which directly connects to the survival of the nation, and through this methodology, identify the agricultural trend of Korea. Based on the relationship between three types of data - policy reports, academic articles, and news articles - the research deducts the major issues stored by each data through LDA, the representative topic modeling method. By comparing and analyzing the LDA results deducted from each data source, this study intends to identify the implications regarding the current agricultural trends of Korea. This methodology can be utilized in analyzing industrial trends other than agricultural ones. To go on further, it can also be used as a basic resource for contemplation on potential areas in the future through insight on the current situation. database of the profitability of a total of 180 crop types by analyzing Rural Development Administration's survey of agricultural products income of 115 crop types, small land profitability index survey of 53 crop types, and Statistics Korea's survey of production costs of 12 crop types. Furthermore, this research presents the result and developmental process of a web-based crop introduction decision support system that provides overseas cases of new crop introduction support programs, as well as databases of outstanding business success cases of each crop type researched by agricultural institutions.

• Journal of health informatics and statistics
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• v.42 no.1
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• pp.53-62
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• 2017

Objectives: The purpose of this study was to provide the basic materials to form sense of value for health and to emphasize the importance of physical education by comparative analysis of physique, physical fitness, body composition and blood. Methods: The subjects were 188 female college students and they were classified 3 groups by BMI: lower weight group (LWG), normal weight group (NWG), and over weight group (OWG). Results: In the physique, there was significantly high in order LWGNWG, OWG in unbalance of the upper and lower parts of the body, and LWG, OWGNWG, OWG in HDL-C. Conclusions: In the result of this study, it is recognized that regular exercise as well as eating right, life style are needed and offered to take part in the exercise programs for healthy campus life of female college students.

• Development and Reproduction
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• v.25 no.3
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• pp.157-171
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• 2021

To determine whether the reproductive processes of sea bass, Lateolabrax japonicus, proceed normally after transportation from an outdoor net-cage into indoor tanks, we examined changes in the gonadosomatic index (GSI), histological gonadal tissue, and plasma levels of sex hormones (testosterone and estradiol-17ß) during their annual reproductive cycle. We also measured maturation and spawning across two sea water salinity levels (full and low salinity). Fecundity was estimated by the relationship between egg number and body size in female sea bass. Monthly changes in the GSI, histological gonadal tissues, and oocyte size showed both male and female sea bass reach final maturation in January and February, respectively, indicating that the spermiation of males occurs earlier than the spawning of females. The histological results indicated that the sea bass is a multiple spawner, similar to many marine teleosts, exhibiting group-synchronous oocyte development. Female maturation and spawning were enhanced in lower salinity seawater (29.6-31.0 psu) compared to that of normal salinity (34.5-35.1 psu). These results confirm that sea bass reproduction can occur successfully in captivity and imply that fertilized eggs can be collected from February to March. Additionally, our results show that lower salinity enhances oocyte maturation and spawning of female sea bass.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.6
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• pp.253-265
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• 2022

This paper examines South Korea's past developmental experience and its current strategy and policy initiatives to overcome global and domestic challenges and sustain economic growth in the twenty-first century, the digital and global era, to explain how the country became a high-income economy. The findings of this research highlight the following three factors: First, the most significant factor in rapid industrialization was the adoption of an outward-looking strategy, with the help of a highly skilled workforce and the development of high-tech manufacturing and services sectors, which was supported by the government plans. Second, the high R&D intensity helped South Korea become a global leader in information and communication technologies, which has emerged from a top-down innovation system that promotes close collaboration between government, industry, and the academic community. Third, according to the recently released Global Entrepreneurship Index, South Korea tops the region in entrepreneurship environment. Among the list of criteria, South Korea dominates in the ease of starting a business and enforcing contracts. They all play a significant role in encouraging investment, production, communication, and, eventually, economic growth. Finally, this paper suggests forward-looking developments promoting transformation and diversification into high-tech manufacturing and digital and green technologies.

• Journal of Korean Public Health Nursing
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• v.36 no.2
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• pp.265-281
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• 2022

Purpose: Adolescence is a developmental period characterized by the rapid growth of the musculoskeletal system, which is important for maintaining correct posture. Incorrect posture, lack of exercise, and reduced physical activity can cause spine deformities and affect lifelong health. This study was designed to evaluate the application and effect of a program for improving adolescents' musculoskeletal health. Methods: A quasi-experimental pilot study was conducted with 13 male and 20 female middle and high school students, with an average age of 15.39 years. Their general characteristics and physical measurements were obtained. The program consisted of group exercises (60 minutes, once per week), gait pattern monitoring, and online communication. A paired t-test and Wilcoxon signed-rank test were used to examine the program's effect. Results: Overall posture habits improved, and the total musculoskeletal index decreased; however, these results were not statistically significant. Conclusions: The devised program was effective in improving musculoskeletal imbalance. Therefore, effective programs and health devices should be developed to help adolescents maintain correct posture and encourage and support continuous participation in such programs.