• Journal of the korean veterinary medical association
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• v.20 no.4
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• pp.219-221
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• 1984

• Journal of the korean veterinary medical association
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• v.47 no.5
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• pp.456-461
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• 2011

최근 홀스타인 경산우는 체격이 대형화함과 동시에 유전적 개량에 의해 비유량이 증가하고 있으나, 비유량이 증가하는 한편, 번식성적의 저하가 전 세계적인 문제로 되고 있다. 미국의 경우, 젖소의 첫 인공수정 수태율은 1951년의 약 65%에서 1996년 약 40%까지 저하하였다는 보고도 있다(Butler 등). 또한 영국에서도 과거 25년간에 수태율이 약 50%에서 35%까지 저하하여 40%를 밑돌고 있으며(Cook 등), 일본의 경우도 마찬가지로 북해도 젖소의 첫 수정 수태율은 40%를 밑돌고 있다는 것으로 미루어 우리나라의 경우도 이와 유사한 성적이나 좋지 않을 것으로 사료된다. 더구나 수태율의 저하와 아울러 분만간격(평균공태일수)는 매년 연장되고, 현재 고능력 젖소에서 번식 성적의 향상은 해결과제로, 세계각국에서는 번식성적저하의 요인 및 대책에 대한 많은 연구가 이뤄지고 있다. 따라서 고능력 젖소에서 유량, 부(負, -)에너지 균형 및 BCS 등이 번식성적에 미치는 영향 등에 대해 국내 외의 수집 논문, 자료 등을 정리하여 대동물임상수의사들에게 도움을 주고자 소개하고 저 한다.

• KDI Journal of Economic Policy
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• v.34 no.2
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• pp.139-171
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• 2012

This paper examines the effect of private tutoring expenditures on academic performance of middle school students in South Korea, using data from "Analysis of the Level of School Education and Its Actual condition: Middle School". In the face of endogeneity of private tutoring expenditures, the paper employs an instrumental variable (IV) method and a nonparametric bounding method. Using both methods we show that the true effect of private tutoring on middle school students remains at most modest in Korea. The IV results suggest that a 10 percent increase in tutoring expenditure for Korean, English and math raises a student's test score of the subject at the largest by 1.24, 1.28, and 0.75 percent, respectively. The bounding results also fail to show evidence that an increase in tutoring expenditure leads to economically and statistically significant improvements in test score.

• KOREAN POULTRY JOURNAL
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• v.39 no.9 s.455
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• pp.90-92
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• 2007

• 종축개량
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• v.12 no.10 s.80
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• pp.43-47
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• 2007

• Monthly Korean Chicken
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• v.52 no.46 s.112
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• pp.66-69
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• 2004

• Journal of the Korean School Mathematics Society
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• v.4 no.1
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• pp.59-68
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• 2001

• Journal of the Korean Data and Information Science Society
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• v.28 no.6
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• pp.1361-1370
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• 2017

In this study, we aimed to identify the relationship between sexual attitude, ego-resiliency, and sexual autonomy in nursing students. The subjects were 226 nursing students who recruited from one college. Data were analyzed using SPSS 20.0 program. The sexual attitude was positively correlated with ego-resiliency (r=.169, p=.011). Also, ego-resiliency and sexual autonomy was positively correlated (r=.148, p=.026). Factors significantly influencing sexual autonomy in nursing students were ego-resiliency (${\beta}=.138$, p=.048), sexual characteristic of participant (${\beta}=-.149$, p=.038), and dating experience (${\beta}=.170$, p=.014). This study showed that the nursing intervention for boosting ego-resiliency and sexual autonomy through healthy and sound dating experience should be required in nursing students.

• Journal of Digital Convergence
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• v.14 no.9
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• pp.461-470
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• 2016

The purpose of this study is to identify relationships among psycho-social maturity, self-efficacy for contraceptive, and sexual assertiveness to see which factors influence sexual assertiveness in male university students. Data were collected from 200 male university students in A city from July 1 to 30, 2015. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients, and stepwise multiple regression. Significant correlations were found among Psycho-Social Maturity, Self-efficacy for Contraceptive, and Sexual Assertiveness. Meaningful variables that influenced Sexual Assertiveness were Self-efficacy for Contraceptive and Psycho-Social Maturity, and the total explanation power was 33%. In conclusion, development of sex education program to increase Sexual Assertiveness of male university students based on the influencing factors is needed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.99-113
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• 1974

This experiment was carried out to find reasonable semi. hot seedbed system for early transplanting of "Tongil"rice cultivar. The quality of the young rice-plants, yield, and the occurrence of the reddish dry leaves were not significant differences between the seedbed with polyethylene tunnel and that of Rat covering. The per cent of healthy seedling of the soil preparation with the dry soil plowing was increased than that of the water soil plowing. The stability of the seedling cultivation of the thin layer straw mulching seedbed beneath the polyethylene film was higher than that of the common flat seedbed system.ed system.