• Animal Bioscience
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• 제36권11호
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• pp.1727-1737
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• 2023

Objective: The poultry industry is a primary source of animal protein worldwide. The gut microbiota of poultry birds, such as chickens and ducks, is critical in maintaining their health, growth, and productivity. This study aimed to identify longitudinal changes in the gut microbiota of laying hens from birth to the pre-laying stage. Methods: From a total of 80 Hy-Line Brown laying hens, birds were selected based on weight at equal intervals to collect feces (n = 20 per growth) and ileal contents (n = 10 per growth) for each growth stage (days 10, 21, 58, and 101). The V4 regions of the 16S rRNA gene were amplified after extracting DNA from feces and ileal contents. Amplicon sequencing was performed using Illumina, followed by analysis. Results: Microbial diversity increased with growth stages, regardless of sampling sites. Microbial community analysis indicated that Firmicutes, Proteobacteria, and Bacteroidetes were the dominant phyla in the feces and ileal. The abundance of Lactobacillus was highest on day 10, and that of Escherichia-shigella was higher on day 21 than those at the other stages at the genus level (for the feces and ileal contents; p<0.05). Furthermore, Turicibacter was the most abundant genus after changing feed (for the feces and ileal contents; p<0.05). The fecal Ruminococcus torques and ileal Lysinibacillus were negatively correlated with the body weights of chickens (p<0.05). Conclusion: The gut microbiota of laying hens changes during the four growth stages, and interactions between microbiota and feed may be present. Our findings provide valuable data for understanding the gut microbiota of laying hens at various growth stages and future applied studies.

• 한국환경복원기술학회지
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• 제13권2호
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• pp.52-62
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• 2010

This study was carried out in the Tropical Plant Resources Research Center of Korea National Arboretum to determine the optimum edaphic environment for the growth of tropical and subtropical plants. The physicochemical properties of artificial substrates and the growth characteristics of tropical and subtropical plants were investigated. Subtropical plants exhibited a high growth rate when cultivated in a substrate of Dry Zone that had physical properties similar to those of arid native soil. Mediterranean plants showed a low growth rate when grown in a substrate of Subtropical Zone that required changes in acidity. The substrate of Tropical Zone had high organic matter and mineral contents and therefore had good physical properties:this substrate has a good environment for the stimulation of the growth of tropical plants. Our results indicate that the chemical properties such as pH and mineral contents of most artificial substrates need to be more urgently improved than their physical properties in order to ensure better growth of tropical and subtropical plants. Initial management strategies for the construction of new tropical greenhouses were formulated, and data from monitoring studies will be continuously gathered and incorporated in the manual to keep it updated.

• 한국인구학
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• 제17권1호
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• pp.1-16
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• 1994

Since 1962, the population growth control has been one of the most important aims in the 5-Year So-cioeconomic Development Plans of Korea. The annual population growth rate has dropped to tess than 1 percent in 1990 from about 3 percents in 1960s, and projected to reach to $\ulcorner$0$\urcorner$ percent in 2021. From 2021, Korean population will decrease and the age structure will be distorted because birth rate will drop suddenly and continuously. Thus, we can consider $\ulcorner$0$\urcorner$ growth population for minimizing the prob- lems on the decreasing population. To discuss the problems caused from the changes of population size and age- sex composition, we projected three kinds of population including two kinds of $\ulcorner$0$\urcorner$ growth population under different as- sumptions. The first is the population which extended the projection of National Statistical Office up to 2090. Because the TFR is assumed and fixed as low as 1.63 after 1990, the population growth rate will be under $\ulcorner$0$\urcorner$ in 2021 and drop by about 1 percent every year from around 2050. This population trend results to old age population : 38.1 of old- age dependency ratio and 46.5 years of median age. The second is the population which the size in 2021 projected by the NOS continues after 2021. To change over from the decreasing population after 2021 to the $\ulcorner$0$\urcorner$ growth one, the TFR should be in-creased up to over 3.0 in 2040-2050, which fertility level would be too high to be accepted. The third is the population which approaches to the $\ulcorner$0$\urcorner$ growth population under the assumptions that the TFR increases from 1.63 to 2.1 in the period of 2010-2030 and then the same level continues. Although the maximum population size reaches 51, 503 thousand persons, the population will approach to the stationary population with about 42.4 million persons around 2090. In this projected population there is no more serious problems on population composition, on the rapid decrease of population, and on the increase TFR level. When the $\ulcorner$0$\urcorner$ growth population continues the problems of over population caused by the populationincrease wou]d be minimized, and the problems of unusual age composition resulted from the popula-tion decrease would not be found any more. Furthermore, when the changes of population size and composition is continuing slowly, the factors of population would effect moderately to socioeconomic development and help social changes. Therefore, with the attention of the present population changes, we should adapt new and detailde population policy which is able to get the $\ulcorner$0$\urcorner$ growth population.

• 대한치과교정학회지
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• 제14권2호
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• pp.217-231
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• 1984

Many investigators have studied the growth changes of craniofacial complex to obtain important informations and standard values with which attempts at prediction of growth and treatment results have been under exploration. The author analyzed 360 cephalometric roentgenograms of 40 boys and 50 girls taken from the ages of 6 to 9 to assess the growth changes of craniofacial complex and to establish Korean norms by Ricketts' analysis method. 17 Landmarks, 10 planes and 8 angles were plotted and measured by linearly and angularly. The results were as follows: 1. The author made the tables of means, standard deviations from the measured values. 2. The item which showed significant difference between males and females in longitudinal study was facial axis length. 3. Items which show significant changes during 3 years were cranial base length, facial axis length, lower incisor to APO, Upper molar to PTV in males, and cranial base length, facial axis length, upper molar to PTV in females. 4. The correlations between cranial base length and facial axis length to body height and weight were higher in males than in females throughout the items.

• 대한원격탐사학회지
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• 제11권2호
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• pp.59-73
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• 1995

The study is focused on the analysis of geomorphological environment changes of alluvial bar in lower Kum river using satellite-based multitemporal/multisensor data. Landsat datas for environment changes analysis consists of Landset MSS(2 scenes) and Landset TM(7 scenes) acquired from 1979 to 1994. This study is to develop the analysis techniques for the environment change detection of using ratio, classification, false color composite etc, of Landsat data especially useful to the geomorphological study of tidal flats and river channels. The results of this study can be summarized as follows : 1. The lower Kum River alluvial bar have had rapid geomorphological changes after the construction of the temporary dam to block the river flowing in 1983. The most alluvial bar located in the river has both bankway growth, especially the allurival bar in the Lower Kum River had grown between 1983 to 1990. 2. After construction of the estuarine barrage, no remarkable geomorphological changes have been found in Kum River area but the growth and formation of new underwater bar has continued. The enormous materials was needed for the growth and formations of new underwater barrier oslands and bar would be supplied from the sea bottom and river sediment to diminish of stream velocity after construction of the estuarine barrage.

• Journal of Ginseng Research
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• 제13권1호
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• pp.60-65
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• 1989

부패된 홍미삼엑기스로부터 분리동정한 내삼투압성 효모인 C. parapsilosis가 홍미삼엑기스의 성분에 미치는 영향을 알아보기 위하여 C. parapsilosis를 배양하면서 pH의 변화, ginsenoside의 함량, 지방산, phenol 화합물 등의 변화를 조사하였다. 엑기스를 소량 첨가하였을 때는 배지의 pH에 다소 영향을 주었으나 엑기스를 다량(10~20%) 첨가하였을 때는 pH에 큰 영향을 미치지 못하였다. C. parapsilosis는 홍삼엑기스의 사포닌의 함량에 영향을 주지 않았고 사포닌을 탄소원으로 이용하지 못하였으며 사포닌 중량 첨가에 따른 생육 촉진경향 혹은 저해현상도 없었다. C. parapsilosis의 홍미삼엑기스의 유리당 이용 패턴은 glucose, fructose 등 단당류를 먼저 흡수 이용하고 다음에 sucrose, maltose 등을 2차적으로 이용하였다. 홍미삼엑기스의 대부분의 지방산은 C. parapsilosis 생육에 의하여 현저히 감소하였으며 이중결합이 없는 stearic acid, palmitic acid는 변화가 거의 없었다. 또한 페놀화합물 중 maltol은 현저히 감소하였고 그 외에 vanillic acid, m-coumaic acid의 함량은 거의 변화가 없었다. 비휘발성 유기산의 함량은 거의 변화가 없었으며 아미노산은 배양 전에 비하여 현저히 감소하였고 특히 arginine은 완전 소진되었다.

• 융합정보논문지
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• 제8권6호
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• pp.15-20
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• 2018

본 연구는 뉴로피드백 훈련을 적용하여 생활습관을 조절하는 자기조절력과 키 성장간의 상관성을 규명함으로 써 키 성장의 효과적인 중재 방안에 대한 해법을 제시하고자 실시하였다. 이를 위해 키 성장 프로그램을 실시하고 있는 초등학교 2학년~4학년 학생 40명(실험군 20명, 대조군 20명) 대상으로 뉴로피드백 훈련 전 후의 변화를 확인하였다. 실험기간은 3개월간(주 2회), 훈련시간은 1회 30분이였다. 뉴로피드백 훈련을 적용한 실험군과 대조군의 자기조절력 차이를 분석한 후, 키 성장 차이를 비교 분석하였다. 첫째, 뉴로피드백 훈련을 적용한 실험군이 대조군에 비해 자기조절력에 유의미한 변화가 있었다. 둘째, 뉴로피드백 훈련을 적용한 실험군이 대조군에 비해 더 크게 키 성장의 변화가 있었다. 이상의 결과를 종합하면 뉴로피드백 훈련이 성장기 학생들에게 있어 키 성장의 후천적 요인들 중 생활습관을 조절하는 자기조절력에 긍정적인 영향을 미치며, 그로 인해 키 성장에도 긍정적인 영향을 미친다는 것이 확인되었다.

• East Asian Economic Review
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• 제25권1호
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• pp.73-97
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• 2021

China has experienced many structural changes in the process of economic development over the past three decades. Using a time-varying parameter VAR model with stochastic volatility and mixture innovations, this study investigates whether such structural changes in, especially tools and operational aims of monetary policy, affect the monetary transmission mechanism. We find that impulse responses of output growth and inflation to monetary shocks have substantially increased and then reversed to decrease around 2005-2006. This time variation is mainly caused by changes in the monetary transmission mechanism, i.e., the manner in which main macroeconomic variables respond to policy shocks, rather than by changes in volatilities of exogenous shocks. The result implies that aggressive monetary policy to facilitate economic growth in the developing economies may be legitimized, unless it causes inflation seriously.

• Asian-Australasian Journal of Animal Sciences
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• 제17권5호
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• pp.655-658
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• 2004

Heat stress is known to affect physiological systems in goats. This study investigated changes in nutrient digestibility, behavior and growth hormone secretion among goats in a hot environment (H; 35${\pm}$ 1.2$^{\circ}C$, [RH] 80${\pm}$7.2%, 13 d), and in a thermoneutral environment (T; 20${\pm}$0.6$^{\circ}C$, [RH] 80${\pm}$3.4%, 20 d), and accompanied by the same restricted diet as provided in the hot environment. The following results were obtained: rectal temperature and water intake were higher in the H treatment than in the T treatment or TR treatment, while hay consumption was lower. CP, NDF and ADF digestibility was highest in H treatment. Time spent eating in the H treatment was also the highest, followed in order by T treatment and TR treatment. Ruminating time was lower in H treatment than in T treatment or TR treatment, and reposing time was highest in the TR treatment. Growth hormone concentrations in T increased 4.5 h after feeding. In H, growth hormone concentrations increased 0.5 h after feeding. However, growth hormone concentrations were not changed following TR feeding. In conclusion, heat exposure in goats decreased feed intake, but increased digestibility. However, when goats in a thermoneutral environment received the same restricted feeding as they received in the hot environment, digestibility increased. Between the H treatment and TR treatment, the changes in digestibility were accomplished by coordinate changes in hormone secretion in order to maintain body homeostasis. To maintain energy balance under a hot temperature or a restricted feeding condition, goats may control their metabolism by changing growth hormone release.

• STI Policy Review
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• 제2권2호
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• pp.11-24
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• 2011

S&T policy has been traditionally regarded as a sector policy; however, it is now evolving into an infrastructure innovation policy that forms the foundation of diverse types of policies. Simultaneously, environmental and energy policies formerly considered as sector policies are now being expanded and integrated into a higher level policy for sustainable development. With these changes underway, the importance of policy integration has increased. Efforts are being made to minimize contradictions between environmental, social, and innovation policies that emphasize proactive linkage among policies or place the highest priority on environmental policy following the theory of Environmental Policy Integration (EPI). Confronted with these policy changes, the Lee Myung-bak government announced "Low-Carbon Green Growth" in 2008 as national agenda for development that focus attention on environmental and energy issues. Economic policy and environmental policy have been traditionally seen in a conflicting relationship with different paths of policy development. However, the administration of President Lee is now emphasizing the synergy effects between the environment and economic growth with the concept of green growth. The green growth policy of the Korean government has great significance as it has built a momentum for incorporating social goals such as environmental values or sustainable development into economic growth-oriented policies; however, there remain many challenges due to the legacy of the development period that has dominated Korean society. The Korean government says it reflects "EPI" or "environmentalism" in policy goals; however, in reality it prioritizes development over the environment.