• Korean Journal of Animal Reproduction
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• v.5 no.1
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• pp.36-42
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• 1981

This experiment was carried out to determine the optimum interval between inseminations in artifical insemination of hens. Two hundred and forty hens of Hisex commercial stock at 25 weeks of age and 20 cocks of the Rhode Island Red at 40 weeks of age were used for the experiment, and a total of 6,784 eggs were obtained. The intervals between inseminations compared in this study were: 3 days (T1), 5 days (T2), and 7 days(T3). Mixed raw semen was inseminated and the semen does was 0.03ml per insemination per hen. The inseminations were conducted at 15:00 at each time. The total number of insemination performed was 9 for the T1, 6 for the T2 and 5 for the T3, and eggs were collected over a period of 31 days, 32 days and 35 dyas, respectively. The average egg production of the hens during the experiment was 85.9% and the average temperature during the experiment was around 30$^{\circ}C$. The average sperm count was 3.69 billion per ml. The results obtained in this experiment can be summarized as follows: The fertility over the entire experimental period bythe treatment was 91.7% for the T1, 84.4% for the T2, and 75.2% for the T3. The difference between T1 and T3 in fertility was significant at 5% level. The average fertility on the second, third and fourth day after the insemination in the T2 and T3 was maintained at a relatively high level, but it tended to decline rapidly from the fifth day after the insemination. The average fertility for one week after the last insemination was 88.8% for the T1, 88.8% for the T2 and 78.6% for the T3, and none of the differences among the treatments were statistically significant. On the basis of the results from this study, it is recommended to adjust the insemination intervals within the range from the 3 to 5 days in order to maintain a highest level of fertility in the hens at an early stage of egg production as in the case of the hens used in this experiment. An insemination interval of 3 days is recommended, especially at an initial stage of insemination. For the hens with a low fertility, shortening, of the insemination interval to 3 or 2 days is desirable.

• Journal of Industrial Convergence
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• v.20 no.5
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• pp.93-100
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• 2022

This study is a descriptive survey study that applies the planned behavior theory to identify the factors influencing the childbirth intention of unmarried men and women. Data were collected from April 05 to April 23, 2021 for 168 unmarried men and women. As a result of the study, in general characteristics, male, old, highly educated, occupational, and non-regular workers had statistically significantly higher childbirth intentions. As a result of examining the correlation between the variables constituting the theory of planned behavior(TPB), it was found that the more positive the attitude toward childbirth, the greater the subjective norm, and the greater the perceived behavior control, the higher the intention to give birth. Multiple regression analyses showed that the factors affecting fertility intention on men and women. The factors affecting fertility intention in men was attitude, with an explanatory power of 62.2% and the factors affecting fertility intention in women were attitudes and perceived behavioral control, and the explanatory power of these variables on fertility intention was 69.0%. In order to increase the intention to give birth, a comprehensive approach is needed, and the research is meaningful in that the results of this study provided basic data in the development of policies and education programs related to low birth rates in the future.

• Korea journal of population studies
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• v.29 no.2
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• pp.89-113
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• 2006

Over the past four decades reproductive behavior has changed rapidly in much of the developing countries. The average total fertility rate has fallen by half from six or more to near three today. Between 1960 and 2000 the largest fertility decline occurred in Asia and Latin America. The mortality rate has also decreased in most developing countries. The purpose of this study is to review the pattern and characteristic of demographic transition in developing countries. At first, this study focuses on the regional fertility and mortality transition. Africa, the total fertility rate is still high, can be match to the second stage of demographic transition. Similar case is found in Southern West Asia areas. However, the fertility rate has therd stage of demographic transition. The same pattern is found in Latin America. The mortality rate has also decreased in most of developing countries. It is interesting to find that there is a clear difference among developing countries. In terms of crude death rate, Latin American countries show the lowest rate. while African countries remain still high rate. About mortality, African countries show a high level in terms of both crude death rate and infant mortality rate. African countries also show the lowest level of life expectancy in the world. One of the reasons for low level of life expectancy in Africa is the widespread of AIDS in this areas. This study suggests that we should include 'AIDS' in the study of mortality in African countries.

• KDI Journal of Economic Policy
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• v.39 no.2
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• pp.25-51
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• 2017

This paper employs an Overlapping Generations Model to quantify the impacts of Korea's demographic transition toward an older population on the total output growth rate. The model incorporates the projected population through 2060 according by Statistics Korea. The effects of the low fertility and increased life expectancy rates are studied. The model is considered suitable for analyzing the effects of demographic changes on the Korean economy. Under the assumption that the TFP growth rate will not slow considerably in the future, remaining at 1.3% per annum, the gross output growth rate of the Korean economy is projected to slow to 1.1% per annum in the 2050s, from 4.0% in the 2000s. The shrinking workforce due to the decline in fertility plays a significant role in the deceleration of the Korean economy. The increased life expectancy rate is expected to mitigate the negative effect, but the magnitude of its effect is found to be limited.

• Journal of Family Resource Management and Policy Review
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• v.20 no.3
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• pp.151-171
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• 2016

The purpose of this study was to identify the relationship between family-friendly policies in working places and the childbearing intentions of married-employed women. The analysis included 415 married working women from the 2012 wave of the Korean Longitudinal Survey of Women and Family. The factors influencing the childbearing intentions of the women were age, education, number of children under age 18, childbirth leave, childcare facilities, and flextime. The women whose work-places provided childbirth leave had stronger childbearing intentions. The women under age 35 had stronger childbearing intentions when their work-places had flextime policies. In conclusion, my recommendation is that the government should pay more attention to the micro-personal factors, such as the Family-friendly Workplace Practices proposed in this study, when executing policies to reverse the current trend of low fertility.

• Journal of the Korea Safety Management & Science
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• v.26 no.3
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• pp.107-113
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• 2024

This study aims to classify types of work-life balance among employees using Latent Profile Analysis (LPA) and investigate variations in depressive symptoms and satisfaction with working conditions across these types. Data were derived from the 6th Korean Working Conditions Survey (KWCS), conducted between 2020 and 2021, which included a sample of 49,479 employed individuals. The LPA revealed three distinct profiles of work-life balance: Low Balance (18.5%), Moderate Balance (72.9%), and High Balance (8.6%). Significant differences in depressive symptoms and satisfaction with working conditions were observed among these profiles. Specifically, the Low Balance group exhibited the highest levels of depressive symptoms and the lowest satisfaction with working conditions, while the High Balance group displayed the lowest depressive symptoms and the highest satisfaction. These findings underscore the critical role of work-life balance in influencing both depressive symptoms and job satisfaction among workers.

• Journal of Family Resource Management and Policy Review
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• v.12 no.3
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• pp.81-101
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• 2008

The purpose of this study is to examine support policies regarding work and family reconciliation, to suggest plans to improve workplace policies, and to suggest directions for further studies. This study looks at OECD's work-life reconciliation policies as well as family friendly workplace policies in Korea to find a way to enhance business' receptiveness and implementation of the policies. By examining women's labor conditions, this study finds that family friendly workplace policies are necessarily imminent in our society of low fertility and ageing. Along with the evaluation of benefit level and the effectiveness of current policies, this study uses data from interviews with working mothers who have had the experience of family friendly benefits. The results of the analyses suggest that the government should focus on improving the workplace environment in companies that do not show bias against the use of family friendly policies. In order to farm more successful policies, future studies are needed to analyze the changes of fertility, working conditions, support programs, and benefits.

• Clinical and Experimental Reproductive Medicine
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• v.50 no.4
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• pp.213-222
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• 2023

Cryopreservation is an option for the preservation of pre- or post-pubertal female or male fertility. This technique not only is beneficial for human clinical applications, but also plays a crucial role in the breeding of livestock and endangered species. Unfortunately, frozen germ cells, including oocytes, sperm, embryos, and spermatogonial stem cells, are subject to cryoinjury. As a result, various cryoprotective agents and freezing techniques have been developed to mitigate this damage. Despite extensive research aimed at reducing apoptotic cell death during freezing, a low survival rate and impaired cell function are still observed after freeze-thawing. In recent decades, several cell death pathways other than apoptosis have been identified. However, the relationship between these pathways and cryoinjury is not yet fully understood, although necroptosis and autophagy appear to be linked to cryoinjury. Therefore, gaining a deeper understanding of the molecular mechanisms of cryoinjury could aid in the development of new strategies to enhance the effectiveness of the freezing of reproductive tissues. In this review, we focus on the pathways through which cryoinjury leads to cell death and propose novel approaches to enhance freezing efficacy based on signaling molecules.

• Journal of Forest and Environmental Science
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• v.31 no.4
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• pp.280-287
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• 2015

Soil samples were collected from three depths (0-10 cm, 10-40 cm and 40-80 cm) of two forest sites including one plantation dominated by teak with some other minor species and another degraded natural forest in Cox's Bazar, Bangladesh to compare their soil properties. Some vegetation parameters were also studied. For this study $10{\times}10\;m$ and $2{\times}2\;m$ quadrats were used for the tree and undergrowth parameters, respectively. Soil samples were also collected from these quadrats. Between the two forest types, the highest levels of organic carbon, total nitrogen, available phosphorus, exchangeable bases and cation exchange capacity (CEC) were found in soils of the plantation. The soils were acidic in nature and exchangeable Al concentrations were low. Teak dominated forest plantation had higher soil fertility index (SFI) than the degraded natural forest site. Steps for reforestation and appropriate protection are needed to improve the situation.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.15-23
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• 1979

In the first paper of the series the five soil fertility factors were evaluated by means of principal component analysis and varimax method. They are interpreted as representing, 1) skeletal available phosporus status, 2) organnic matter status, 3) salt status 4) base status, and 5) free oxide status. In order to resynthesize such fragmented information for the overall soil fertility evaluation, the method of multiple regression analysis was adopted, using the five factor scores and yield data for Korean paddy soils as independent and dependent variables respectively. As test of linear models with different combinations of independent variables the results of t-test of regression coefficient were revealed that the organic matter status (FII) has no relevance to the yield of paddy and that the free oxides and salt supply has by it self only an insignificant contribution to the yield. The multiple correlation coefficient (R) revealed its multiple regression analysis was as low as 0.43. Introduction of quadratic terms to the linear model bettered the result. Thus multiple correlation coefficient (R) was increased as 0.59. Therefore, a coefficient of determination 0.35 was obtained by a quadratic model with interaction terms among the five fertility constituents. Generally we think that the fertility factor has more contribution to raise the rice yield in paddy and that the failure of yield prediction by fertility factor scores was caused by one of follows; 1) the roughness of the yield inspection, and 2) missextraction of fertility constituents. The second step in this study, assuming that the residuals by multiple regression analysis were due to factors other than soil fertility, we can now proceed to predicting the yield from the field characters with the classified fertility groups by means of Hayashi's theory of quantification No. 1. Such variables as fertility groups (FTYG), water availability (WATER), soil drainage (DRNG), climatic zone (CLIZ), surface soil's stickiness (STCKT), surface soil's dry consistence (DCNST), and surface soil's texture (FTEXT) are taken up as the explanatory variables. The quantification appears reasonable; the well to extremely well in soil drainage, very sticky of surface soil, inefficiency in water availability, coarse texture, and very hard to extremely hard dry consistence in soil are detrimental to the rice yield. The R was as high as 0.90 for the set of variables. But the given explanatory variables in this study were not quite effective in explaining rice yield. The method developed seems to be promising only if properly collected data are available. Conditions that should be satisfied in the yield inspection obtained from common cultivator for the purpose of deriving a prediction equation were put forward.