• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2977-2983
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• 2023

During normal operation, some parts of the fission product in the defective fuel rods can release into the primary loops in PWR and the escape rate coefficients are widely used to assess quantitatively the release behaviors of fission products in the industry. The escape rate coefficients have been standardized and have been validated by some drilling experiments before the 1970s. In the paper, the model to determine the escape rate coefficients of fission products has been established and the typical escape rate coefficients of noble gas and iodine have been deduced based on the measured radiochemical data in one operating PWR. The result shows that the apparent escape rate coefficients vary with the release-to-birth and decay constants for different fission products of the same element. In addition, it is found that the escape rate coefficients from the defective rod with large defects are much higher than the standard escape rate coefficients, i.e., averagely 4.4 times and 1.8 times for noble gas and iodine respectively. The enhanced release of fission products from the severe secondary hydriding of several defective fuel rods in one cycle may lead to the potential risk of the temporary shutdown of the operating reactors.

• Journal of Preventive Medicine and Public Health
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• 제23권1호
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• pp.87-97
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• 1990

1985년 4월 1일부터 1987년 3월 31일 사이에 경상북도 군위군에 거주하는 49세이하의 가임여성들과 1987년 3월 1일부터 1988년 2월 28일 사이에 경상남도 합천군에 거주하는 49세이하의 가임여성들 그리고 1985년 4월 1일부터 1987년 3월 31일 사이에 대구시 남구 모자보건센터에 분만을 위해 찾아온 모든 임산부들을 대상으로 이들에게서 태어난 출생아들을 두 군지역에서는 생후 1년간 그리고 모자보건센터에서 출생한 경우는 생후 27일간 추적하여 영아사망률과 신생아 사망률을 각각 조사하였다. 조사기간중에 군위군과 합천군에서 출생한 1,359명의 영아들 가운데 생후 1년 동안에 17명이 사망하여 농촌지역의 영아사망률은 출생아 1,000명당 12.5이었다. 총 영아사망중 신생아사망이 82.4% 그리고 신생아 후기 사망이 17.6%를 차지하였다. 대구시 남구 모자보건센터에 내원한 산모들에게 태어난 6,001명의 출생아들 가운데 4,834명(80.6%)만이 생후 27일까지 추적되었는데 이들 중 36명이 사망하여 신생아 사망률은 출생아 1,000명당 7,4명이었다. 추적된 산모와 추적 안된 산모의 특성 및 신생아 체중을 비교한 결과 현저한 차이를 나타내지 않았다. 신생아 후기 사망률의 비를 6 : 4로 가정했을 때 모자보건센터에서 출생한 영아의 영아사망률은 출생아 1,000명당 12.3명으로 추정되었다. 군위군과 합천군의 영아사망률과 대구시 남구 모자보건센터에서 관찰된 신생아사망률, 영아사망의 사망시기별 분포와 영아사망원인 그리고 저체중아출생률을 고려할 때 1985년부터 1988년 사이의 한국의 영아사망률은 출생아 1,000명당 12에서 15명일 것으로 추정되었다.

• Clinical and Experimental Pediatrics
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• 제63권8호
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• pp.284-290
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• 2020

Korea currently has the world's lowest birth rate but a rapidly inreasing number of preterm infants. The Korean Neonatal Network (KNN), launched by the Korean Society of Neonatology under the support of Korea Centers for Disease Control, has collected population-based data for very low birth weight infants (VLBWIs) born in Korea since 2013. In terms of the short-term outcomes of VLBWIs born from 2013 to 2016 registered in the KNN, the survival rate of all VLBWIs was 86%. Respiratory distress syndrome and bronchopulmonary dysplasia were observed in 78% and 30% of all VLBWIs, respectively. Necrotizing enterocolitis occurred in 7%, while 8% of the VLBWIs needed therapy for retinopathy of prematurity in the neonatal intensive care unit (NICU). Sepsis occurred in 21% during their NICU stay. Intraventricular hemorrhage (grade ≥III) was diagnosed in 10%. In terms of the long-term outcomes for VLBWIs born from 2013 to 2014 registered in the KNN, the post-discharge mortality rate was approximately 1.2%-1.5%, mainly owing to their underlying illness. Nearly half of the VLBWIs were readmitted to the hospital at least once in their first 1-2 years of life, mostly as a result of respiratory diseases. The overall prevalence of cerebral palsy was 6.2%-6.6% in Korea. Bilateral blindness was reported in 0.2%-0.3% of VLBWIs, while bilateral hearing loss was found in 0.8%-1.9%. Since its establishment, the KNN has published annual reports and papers that facilitate the improvement of VLBWI outcome and the formulation of essential healthcare policies in Korea.

• Clinical and Experimental Reproductive Medicine
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• 제47권2호
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• pp.135-139
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• 2020

Objective: In the present study, we aimed to retrospectively evaluate the cumulative live birth rate (LBR) after up to three consecutive embryo transfer (ET) cycles, either fresh or frozen, in women with expected poor ovarian response (ePOR). Methods: We selected 115 women who entered the first in vitro fertilization (IVF) cycle between August 2013 and July 2016. The women were divided into an ePOR group (37 women) and a non-ePOR group (78 women). All women in the ePOR group were ≥ 40 years old or had serum anti-Müllerian hormone levels of less than 1.1 ng/mL at the time of the first IVF cycle. Live birth outcomes were monitored until December 2017. The cumulative LBR (with both conservative and optimistic estimates) was calculated according to the serial number of ET cycles. Results: After up to three ET cycles, the overall cumulative LBR was significantly lower in the ePOR group than in the non-ePOR group (conservative estimate, 10.8% vs. 44.9%, respectively; optimistic estimate, 14.7% vs. 56.1%, respectively; log-rank test, p= 0.003). Conclusion: Women with ePOR exhibited a lower cumulative LBR than women in the non-ePOR group, and this information should be provided to ePOR women during counseling before starting IVF.

• Clinical and Experimental Reproductive Medicine
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• 제48권3호
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• pp.255-261
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• 2021

Objective: This study aimed to investigate sperm motility and its changes after preparation as predictors of pregnancy in intrauterine insemination (IUI) cycles. Methods: In total, 297 IUI cycles from January 2012 to December 2017 at a single tertiary hospital were retrospectively analyzed. Patient and cycle characteristics, and sperm motility characteristics before and after processing were compared according to clinical pregnancy or live birth as outcomes. Results: The overall clinical pregnancy rate per cycle was 14.5% (43/297) and the live birth rate was 10.4% (30/289). Patient and cycle characteristics were similar between pregnant and non-pregnant groups. Sperm motility after preparation and the total motile sperm count before and after processing were comparable in terms of pregnancy outcomes. Pre-preparation sperm motility was significantly higher in groups with clinical pregnancy and live birth than in cycles not resulting in pregnancy (71.4%±10.9% vs. 67.2%±11.7%, p=0.020 and 71.6% ±12.6% vs. 67.3%±11.7%, p=0.030, respectively). The change in sperm motility after processing was significantly fewer in the non-pregnant cycles, both when the comparison was conducted by subtraction (post-pre) and division (post/pre). These relationships remained significant after adjusting for the female partner's age, anti-Müllerian hormone level, and number of pre-ovulatory follicles. According to a receiver operating characteristic curve analysis, an initial sperm motility of ≥72.5% was the optimal threshold value for predicting live birth after IUI. Conclusion: Initial sperm motility, rather than the motility of processed sperm or the degree of change after preparation, predicted live birth after IUI procedures.

• 한국가금학회지
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• 제31권3호
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• pp.157-164
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• 2004

육용계의 성장률 개량을 위한 조기 선발시, 부화시 체중과 부화시 정강이 길이 중 어느 형질을 기초로 하여 선발하는 것이 성장률 개량을 위해서 더 효율적인 방법인가를 조사하기 위하여 국내의 일반 농가에서 주로 사육되고 있는 육용계 품종 중 Cobb 종과 Ross 종 두 품종을 이용하여 5주간 시험하였으며, 시험구 배치는 부화 당일에 각 품종별로 병아리 200수중에서 부화시 체중이 무거운 그룹(HBW)과 가벼운 그룹(LBW), 혹은 부화시 정강이 길이가 긴 그룹(LSL)과 짧은 그룹(SSL)으로 나누고 각 그룹당 25수씩(수평아리, 13수: 암평아리, 12수)선발하여 배치하였던 바 그 결과는 다음과 같다. 두 품종 모두 부화시 체중이 유의하게(P < 0.05)더 무거웠던 개체들은 일반적으로 정강이 길이도 유의하게(P < 0.05)더 길었다. 시험 종료시 체중을 기초로 하여 그룹간에 비교를 하였을 때, Cobb 종은 BBW와 LSL간, 혹은 LBW와 SSL 그룹 상호간에는 유의한 차이가 없었고, HBW는 LBW 보다, 그리고 LSL은 SSL보다 유의하게 5주령시 체중이 더 무거웠던 반면에, Ross 종에서는 4그룹 상호간에 통계적인 유의성을 나타낼 만큼 체중의 차이를 보이지는 않았다. 한편 0 ～ 5주령간 정강이 길이의 변화에 대한 비교에 있어서는 두 품종 모두 4그룹 상호간에 크게 차이를 나타내지 못하였다. 부화시 체중(BW)과 0～5주령간 성장률(GR), BW와 0～5주령간 정강이 길이(SL), 혹은 GR ${\times}$ SL 상호간 상관분석의 결과, 일반적으로 GR ${\times}$ SL 상호간에만 두품종 모두 유의한(P < 0.05 ～ 0.001)상관관계를 나타내었다. 결론적으로 성장률 개량을 위하여 조기 선발을 하는 경우, 부화시 체중을 기초로 하여 선발을 하든지, 아니면 부화시 정강이 길이에 의해 선발을 하든지 간에 부화 이후의 성장률에는 크게 차이가 없어 체중을 측정하는 것보다 정강이 길이를 측정하는데 시간이 더 많이 걸리고, 또한 정강이 길이를 측정하는 것이 체중을 측정하는 것보다 상대적으로 정확도가 떨어지기 때문에 부화시 체중을 기초로 하여 성장률 개량을 도모하는 편이 더 용이하리라 사료된다.

• Reproductive and Developmental Biology
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• 제32권1호
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• pp.51-58
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• 2008

본 연구는 체세포 복제 한우 송아지의 생산에서 생시체중과 생존성과의 관계에 대하여 살펴보고자 실시하였다. 293두의 한우 대리모에 580개의 복제란을 이식하였다. 복제란의 임신율은 이식 후 50일까지 72.3%로 높았으나, 이후 급격하게 감소하였다. 평균 임신 기간은 복제 송아지에서 287일($279{\sim}295$일)이었으며, 인공수정 송아지도 287일($255{\sim}293$일)로 각각 나타났다. 복제 송아지의 생시체중(30.3kg)은 인공수정 송아지(23.7kg)에 비하여 유의하게 높은 것으로 나타났다(p<0.05). 자연분만(n=17, 29.9kg)과 제왕절개(n=14, 32.3kg)로 태어난 복제 송아지의 생시체중은 차이가 없었다. 하지만, 생후 175일 이전에 사망한 복제 송아지(n=18, 32.8kg)의 생시체중이 175일 이상 생존한 복제 송아지(n=11, 28.3kg)보다 유의적으로 높게 나타났다(p<0.05). 흥미로운 점은 생시체중이 15kg 이하(n=5) 또는 35kg 이상(n=9)인 복제 송아지들은 모두 생후 175일 이전에 폐사하였다. 생후 175일 이전에 폐사한 복제 송아지들(n=20)의 사망 원인은 미성숙 개체 2두(10.0%), 폐와 간 이상 2두(10.0%), 폐의 원인 4두(20.0%), 기형 4두(20.0%), 출생 후 급사(sudden death syndrome) 4두(20.0%) 및 기타 원인불명이 4두(20.0%) 등으로 분류되었다. 이상의 결과를 종합하여보면, 복제 송아지의 정상 생시체중이 6개월 이상을 생존하는데 가장 중요한 요소들 중의 한 가지임을 확인하였다.

• 한국보육지원학회지
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• 제16권4호
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• pp.1-29
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• 2020

Objective: The present study aimed to explore the experiences of mothers who have abandoned their additional birth plans since their first child was born. Methods: During in-depth interviews, mothers were asked to recall their own experiences of motherhood. The interview data were analyzed using the grounded theory. Results: The central phenomenon was 'The burden of raising a child is too heavy for mothers to carry alone.' The causal conditions were 'First experience: Unpredictable life', 'Physical and psychological difficulty', and 'Spouse's absence.' The contextual conditions were 'Expectations and reality of parenting' and 'Workplace conditions.' The mothers used interaction strategies of 'Defusing conflict only on a surface level: Giving up', 'Reliance on grandmothers', and 'Downgrading career aspirations.' These strategies were mediated by intervening conditions, 'Stereotypes and experiences of non-family nanny', 'Child's development', and 'Family conflict.' The results were 'Endless guilt', 'Ambivalence between independence versus interdependence' and 'Unfairness: Why only me?' Finally, the process of psychological conflict was identified to account for the steps leading mothers to give up on their birth plans. Conclusion/Implications: During the first experience of motherhood, mothers' conflict gets escalated despite their struggles. These experiences might discourage their additional birth plans. These results provide implications for policies to increase fertility rates.

• 한국동물위생학회지
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• 제46권2호
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• pp.147-156
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• 2023

Between February 2020 and September 2021, a total of 452 dairy calves with diarrhea were investigated across 17 dairy farms in Gyeonggi province, Korea, using a rapid diagnostic kit. The study aimed to examine the infection rates of major pathogens causing diarrhea in dairy calves, categorizing them by season, age, and birth month. Additionally, logistic regression analysis was conducted to investigate the factors affecting the infection rate. The infection rates of the major pathogens causing infectious diarrhea in dairy calves, including bovine rotavirus, bovine coronavirus, Cryptosporidium, and E. coli, are influenced by season, age, and birth month. Bovine coronavirus and Cryptosporidium showed variations in infection rates according to season, age, and birth month, while bovine coronavirus was influenced by age and birth month, and E. coli showed variations in infection rates based on age. Furthermore, in the analysis of risk factors influencing the infection rates of these pathogens, age and birth month were identified as risk factors for bovine rotavirus, bovine coronavirus, and Cryptosporidium.

• 한국인구학
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• 제14권1호
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• pp.55-69
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• 1991

The objective of the study is to figure out the status of reproductive health and general characteristics related to maternal health for Korean-Americans living in Los Angeles. We collected data from the married women who wanted no more additional child birth and were attending the Family Planning Clinic of Koryo Health Foundation in Los Angeles during 1988. There were 494 women met the eligibility requirement for this study. The results are summarized below. 1. In the age distribution of the women who desired no more additional child birth, women 30-34 age group constituted the largest proportion at 36.6 percent ; the mean age of women was 35.1915.55. The mean number of child birth was 1.77, and the proportion of the women by number of child birth were 35.2 percent for one children, 50.1 percent for two children 10.5 percent for three children, and 2.6 percent for four children. All of the women experienced pregnancy at least once, and mean number of pregnancy was 3.42. The mean number of total experience of induced abortion was 1.56. and 76.7 percent of these women had experience with induced abortions. To prevent further pregnancies, 90.1 percent of the women were utilizing the contraceptive methods, and the highest proportion by the contraceptive methods was condoms(53.7%), 9.3 percent in spermicides, 8.7 percent in IUDs, 8.7 percent in rhythm method, and 6.9 percent in oral pills. 2. The mean age of women at each stage of reproductive life cycle were 14.74 years at time of menarche, 24.55 years at time of marriage, 26.60 years at time of the first child birth, and 28.75 years at time of the last child birth. In age distribution of the women by birth cohort (Group I : birth cohort 1940-1954, Group H : birth cohort 1955-1970), the mean menar-cheal age of the women was 14.96 years in group I , and 14.53 years in group H . Mean age at time of marriage was 25.01 years in group I and 24.08 years in group H . Mean child birth age of the women by birth cohort was 27.19 years In group I and 26.01 years in Group II for the first child birth and 30.07 years in group I and 27.45 years in group II for the last child birth. The total length of reproductive life cycle from menarche to menopause (presumed to be at 49 of age years) was 34.26 years. The len-gth of phase I (from menarche to marriage) was 9.81 years, while phase H (marriage to first birth) was 2.05 years, and phase Ill (first birth to last birth) was 2. 15 years, and the last phase of reproductive life cycle, phase IV (last birth to menopause) was 20.25 years. The proportion of each phase 10 total length of reproductive life cycle was 28.6 percent, 6.0 percent 6.3 percent, and 59.t percent respectively. In the tendency of each phase in reproductive life cycle by birth cohort (group I , U ), the length of phase I, II , III of birth cohort group II was diminished in comparison with those of birth cohort group I , but the length of phase IV was extended by 2.38 years. 3. Among the women, the mean number of total pregnancy by birth cohort group was 2.01 in group I and 1.10 in Group II, and mean number of child birth was 1.97 in group I and 1.58 in group II. In terms of pregnancy was-tage rate by birth cohort group, among the total pregnancy of birth cohort group I , 51.8 percent of the cases resulted in induced abortions or spontaneous abortions whils 48.2 percent resulted in live births, and 42.2 percent or total pregnancy in group II resulted in pregnancy wastage and 57.8 percent of the cases resulted in live births.