• International Journal of Industrial Entomology and Biomaterials
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• 제19권2호
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• pp.215-219
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• 2009

The effect of mating duration and multiple use of male on fecundity and fertility was investigated in the hybrids of Silkworm, Bombyx mori L. One hour to five hours of mating duration did not affect egg laying (fecundity) significantly, while fertilization affected significantly. Below 50% fertility was noticed when mating duration was reduced to below two hours. Similarly multiple use of male caused significant reduction in fertility but not fecundity. Till fourth mating no significant reduction in fertility was observed, thereafter fertility reduced considerably.

• 한국인구학
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• 제11권1호
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• pp.97-116
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• 1988

This study examines the socioeconomic determinants of fertility behavior in Korea by developing a model which simultaneously takes into account both individual and community-level differences. It especially focuses on the micro-macro nexus of fertility behavior depending on social contexts. This study utilizes micro data obtained from the 1974 Korean National Fertility Survey(KNFS), and macro data obtained from Korean government statistics. The framework of the model is formalized as a set of structural equations modelling the fertility process. The model is formed on a cohort-specific processual basis and is restricted to five-year birth cohorts. Three cohorts of women are studied : those aged 30-34, 35-39, and 40-44. The model includes three fertility-process components : age at first birth, early fertility, and later fertility, which are defined by reference to the age of the mother. The results of this study indicate that socioeconomic development in Korea results in increased age at first birth and reduced numbers of children per couple. In addition to the developmental change, Korea's fertility decline is found to be facilitated by family planning programs. As expected, the effect of family planning on fertility is greater among better-educated women than among poorly educated women. The inconsistent but suggestive result, however, is that the effect of socioeconomic development on fertility is greater among less-privileged women than among more-previleged women.

• 가족자원경영과 정책
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• 제25권2호
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• pp.41-52
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• 2021

본 연구의 목적은 여성의 경제활동참가율과 가족정책변수, 양성평등가치변수가 출산율에 미치는 영향을 규명하는 것이다. 이를 위해 1990년부터 2019년까지 30년 간 OECD회원국의 출산율 자료와 UNDP 자료, World Value Survey 자료를 시계열로 결합한 패널데이터를 분석하였다. 종속변수인 출산율에 영향을 미치는 독립변수는 1단계에서 여성의 경제활동참가율과 통제변수를 투입하였고, 가족정책변수, 양성 평등가치변수 순으로 변수를 추가하면서 각 변수들의 변화를 비교하였다. 주요 분석 결과 첫째, 여성의 경제활동참가율은 각 모형에서 출산율에 양의 영향을 보였다. 즉, 여성의 경제활동참가로 인해 출산율이 감소되는 현상이 나타나지 않았다. 둘째, 가족정책변수인 부성 출산휴가기간이 출산율에 정적 영향을, 모성 출산휴가기간이 부적 영향을 미치는 상반된 효과를 보였다. 셋째, 양성평등가치변수인 성불평등지수가 높은 국가에서 출산율이 높았다. 또한 성평등 가치 수준이 높은 국가일수록 출산율이 낮았으며, 성평등 가치관을 3개 하위지표로 분리하여 분석했을 때 대학교육의 중요성에 양성 평등한 가치를 보일수록 출산율이 낮았다. 여성의 경제활동참가율이 출산율에 정적 영향을 미친 결과는 경제활동이 저출산의 원인이 아니며, 경제활동참여와 출산율이 동시에 상승할 수 있음을 보여준다. 또한 남녀의 출산휴가와 같은 정책적 지원, 그리고 남녀의 성평등 가치가 출산율을 조절할 수 있는 요인임이 확인되었다. 따라서 출산율은 가족의 시간, 소득 등 자원에 대한 배분과 관리, 자녀양육분담의 차원에서 이루어지는 의사결정이나 이를 지원하는 가족정책과 성평등 가치가 통용되는 사회적 기반 위에서 제고될 수 있을 것이다.

• 한국작물학회지
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• 제46권2호
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• pp.145-149
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• 2001

This study was performed to evaluate the growth and nodulation characters of hypernodulating soy-bean mutant, SS2-2, and to know the growth and yield performance of the mutant in infertile soil. Soil fertility was adjusted by mixing the different ratios of soil components including clay, river sand, and horticultural bed, which resulted in fertile and infertile soil. Dry weight, nitrogen concentration, and leaf nitrate reductase of each plant were measured around V6 stage (47 days after planting) and around R3 stage (82 days after planting). There were significant effects of soil fertility and soybean genotype on the total dry weights including root, nodule, stem, leaf, and pod dry weight at V6 and R3 stages. Total dry weight of hypernodulating mutant, SS2-2, was clearly less than that of its wild type, Sinpaldalkong 2. However, nodule development on the roots of SS2-2 was much greater than that of Sinpaldalkong 2, regardless of soil fertility. Though SS2-2 was smaller in plant size than Sinpaldalkong 2, genotypic difference in total nitrogen content was not significant at both V6 and R3 stages because SS2-2 fixed more nitrogen biologically than its wild type in the root nodule. The SS2-2 mutant showed lower plant yield in both infertile and fertile soil. The SS2-2 contained more crude seed protein than Sinpaldalkong 2, and was characterized with reduced top and root growth.

• 한국가금학회지
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• 제30권2호
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• pp.95-99
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• 2003

본 연구는 육용종계 암컷과수컷의 배웅비를 달리할 경우 종란의 수정율과 부화율에 미치는 영향을 구명하고자 실시 하였다. 육용종계 암컷과 수컷 비율이 각각 9:I(암컷:수컷＝11:99), 11:1(9:99), 및 13:1(8:104) 이 되도록 하여 3.2 ${\times}$ 6.4m 크기의 pen에 사육하였다. 각 처리당 3반복으로, 30주령된 Ross 종계 수컷 112수 암컷 1,208수를 시험에 공시하였다. 30주령시 종란의 수정율은 93 ∼ 94% 내외로 처리간 유의차가 발견되지 않았다.

• 한국인구학
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• 제30권3호
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• pp.137-156
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• 2007

합계출산율이 2005년 1.08이라는 최저치에서 2006년 1.13으로 증가하면서, 이 증가가 각종 정책의 결과이기 때문에 출산력 증가가 지속될 것이라는 주장과 일시적일 것이라는 주장 간 논란이 있다. 이 연구는 인구동태신고 자료를 활용하여 최근의 출산력 변화를 집중적으로 살펴봄으로써 정책 시사점을 찾고자 하였다. 이를 위하여 출산순위별 템포조정합계출산율, 모의 연령 및 출산순위별 출산율, 연령별 유배우 출산율, 연령별 유배우 이혼율 등을 분석하였다. 전년대비 2006년 합계출산율과 출생아수가 증가한 것은 여성의 초혼과 첫째아 출산의 연기가 주춤해지면서 주로 30대 초반의 첫째아 출산 증가에 기인한다. 2006년과 2007년에는 20대 후반 여성인구의 증가(제3차 베이비붐 효과) 및 초혼의 급증으로 2007년과 2008년에는 출생아수가 증가할 것이다. 다만, 20대의 미혼율은 증가하구 유배우 출산율은 감소 추세이어서 장기적 관점의 출생아수 및 출산율 증가는 미지수이다. 또한, 첫째아와 둘째아의 출산율은 급속도로 저하되는데 반해, 셋째아 이상은 변화가 없으며, 둘째아 출산이 출산연령조정의 영향을 많이 받는 것으로 나타났다. 이는 셋째아 이상을 출산하도록 장려하는 것보다는 첫째아, 둘째아를 낳을 수 있는 사회적 환경 조성이 더 필요하고 현실적임을 시사한다. 아울러, 사회적 양육대책 마련, 고령출산에 따른 모자보건문제, 다문화가정지원책 필요성 등을 언급하고 있다.

• 아시안잔디학회지
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• 제13권2호
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• pp.79-90
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• 1999

This study was conducted to provide basic understandings for proper management of zoysiagrass fairways. Mowing intervals of 2, 4 and 6-days, with and without aeration were compared at two fertility levels. Turfgrass quality, growth and pest infestation were evaluated. Turf density, number of tillers, leaf width and resiliency were significantly affected by mowing frequency. Turfgrass plots mowed every 2-day had greater density, tillering, and resiliency but had narrower leaf width compared to other mowing treatments. Clipping dry weight with every 2-day mowing increased in the early stage of mowing treatment regardless of fertilizer application rates but gradually decreased in the later stage of mowing treatment compared to every 4 or 6-day mowings. The dry weight of above-ground part was not affected by mowing frequency, but that of underground part was significantly higher for every 6-day mowing frequency(3.3kg/day/m2) compared to every 2 or 4-day mowings. The organic mater content in soil was not different among mowing treatments but it was significantly reduced by the core aerification treatment, indicating significant effect of core aerification on thatch decomposition. Occurrences of weeds such as annual bluegrass and crabgrass according to mowing frequency were greater in every 2-day mowing treatment, while plots mowed every 6 days had less weed occurrence. Occurrence of rusts significantly increased in high fertility plots and frequently mowed turfgrasses.

• Animal Bioscience
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• 제36권3호
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• pp.385-403
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• 2023

Male fertility is affected by multiple endogenous stressors, including reactive oxygen species (ROS), which greatly deteriorate the fertility. However, physiological levels of ROS are required by sperm for the proper accomplishment of different cellular functions including proliferation, maturation, capacitation, acrosomal reaction, and fertilization. Excessive ROS production creates an imbalance between ROS production and neutralization resulting in oxidative stress (OS). OS causes male infertility by impairing sperm functions including reduced motility, deoxyribonucleic acid damage, morphological defects, and enhanced apoptosis. Several in-vivo and in-vitro studies have reported improvement in quality-related parameters of sperm following the use of different natural and synthetic antioxidants. In this review, we focus on the causes of OS, ROS production sources, mechanisms responsible for sperm damage, and the role of antioxidants in preserving sperm fertility.

• Human Ecology Research
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• 제53권1호
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• pp.49-66
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• 2015

This study analyzes the effects of women's labour force participation and work-family reconciliation support on life-cycle fertility in Korea. The analysis is based on the longitudinal data from Korean Labour and Income Panel Study (KLIPS), which include the available information on life-cycle fertility and employment history. Employing a dynamic model of fertility, we estimated the life-cycle fertility of all the 15-49 years old women considered in this study by using a duration model. The major results of this study were as follows: First, women's labour force participation had a negative effect on the first birth, second birth, and all births (transition to births starting at different parities). Women's employment tended to lengthen the interval between births. Second, the availability of maternal leave had a positive effect on the first birth and all births for working women. Providing maternal leave to working women decreased the opportunity cost of childbearing and in turn, reduced the interbirth interval of women. However, the availability of parental leave had no significant effect on the births of working women. Third, the financial support for childcare had a positive effect on the first birth and all births. The economic support for childcare led to the reduction in the interbirth interval of women by increasing the probability of births. The use of a childcare center for the first child, which substitutes for the time that women needed to take care of their children, classified as time-intensive consumption goods, did not have any effect on the second birth. Fourth, the part-time employment of women had a positive effect on the second birth. A flexible working time schedule tended to decrease the interval between the first and the second births.

• 한국작물학회지
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• 제54권2호
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• pp.192-197
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• 2009

지구온난화 등에 따른 세계적 환경변화에 대응하고 정부의 친환경 농업육성 정책에 부응하는 정밀농업기술 중 GPS를 이용한 이앙과 동시 변량시비가 벼 생육 및 품질에 미치는 영향을 구명한 결과는 다음과 같다. 1. 시험전 후 토양 질소검정량에 대한 공간변이 정도를 나타내는 Nugget값은 관행 대비 변량시비 후 낮아졌고, 공간구조 강도를 나타내는 Q값은 두 처리 모두 없어 공간의 존성이 존재하지 않았다. 2. 분얼기부터 성숙기까지 초장, 경수, 수수 등의 생육량은 관행 대비 변량시비에서 증가되었고 생육 요인별 변이계수가 낮아 상대적으로 균일한 경향을 보였다. 3. 완전미 수량은 관행 450 kg 대비 변량시비에서 492 kg으로 유의성 있게 증가 되었고 변이계수는 현저히 낮아졌다. 4. 아밀로스, 단백질 함량, 백도 등 품질은 처리간 큰 차이가 없었으나 변이계수는 변량시비에서 낮아졌다. 5. 비료살포작업에 대한 투입노동력은 관행 11.8시간/ha 대비 변량시비에서 61%(7.2시간)가 절감 되었다.