• Journal of Wetlands Research
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• v.20 no.1
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• pp.27-34
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• 2018

Reproductive phenology and physiological responses of Epilobium hirsutum L. to moisture content and nutrient content of soil were analysed in order to obtain basic data for effective conservation and restoration. Epilobium hirsutum L. is a perennial plant. But Epilobium hirsutum L. grew reproductively in all moisture and nutrient gradients. Flower bud, flowers and peduncle were respectively ripened in earlier under highest moisture condition and highest nutrient condition. And, number of flowers and peduncle were more quickly increased under highest moisture condition and highest nutrient condition. Chlorophyll content was high under highest moisture condition and higher middle moisture condition. However, we found no significant difference of chlorophyll content regard to nutrient gradients. There was no difference in minimum chlorophyll fluorescence among all moisture and nutrient gradients. The photochemical efficiency values of PS II were 0.75 in all moisture gradients, and it was 0.78 in highest nutrient gradient. The chlorophyll content of Epilobium hirsutum L. increased as the moisture content increased, and the Fv/Fm value increased as the organic matter increased. Our results showed that high moisture and nutrient content of soil advance their breeding season and promote reproductive growth. It might be important basic informations for the maintenance of population and the management of habitat of Epilobium hirsutum L. an endangered plant species.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.333-343
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• 2015

This research aims at identifying the goshawk's possible and replaceable breeding ground by using the MaxEnt prediction model which has so far been insufficiently used in Korea, and providing evidence to expand possible protection areas for the goshawk's breeding for the future. The field research identified 10 goshawk's nests, and 23 appearance points confirmed during the 3rd round of environmental research were used for analysis. 4 geomorphic, 3 environmental, 7 distance, and 9 weather factors were used as model variables. The final environmental variables were selected through non-parametric verification between appearance and non-appearance coordinates identified by random sampling. The final predictive model (MaxEnt) was structured using 10 factors related to breeding ground and 7 factors related to appearance area selected by statistics verification. According to the results of the study, the factor that affected breeding point structure model the most was temperature seasonality, followed by distance from mixforest, density-class on the forest map and relief energy. The factor that affected appearance point structure model the most was temperature seasonality, followed by distance from rivers and ponds, distance from agricultural land and gradient. The nature of the goshawk's breeding environment and habit to breed inside forests were reflected in this modeling that targets breeding points. The northern central area which is about $189.5 km^2$(2.55 %) is expected to be suitable breeding ground. Large cities such as Cheongju and Chungju are located in the southern part of Chungcheongbuk-do whereas the northern part of Chungcheongbuk-do has evenly distributed forests and farmlands, which helps goshawks have a scope of influence and food source to breed. Appearance point modeling predicted an area of $3,071 km^2$(41.38 %) showing a wider ranging habitat than that of the breeding point modeling due to some limitations such as limited moving observation and non-consideration of seasonal changes. When targeting the breeding points, a specific predictive area can be deduced but it is difficult to check the points of nests and it is impossible to reflect the goshawk's behavioral area. On the other hand, when targeting appearance points, a wider ranging area can be covered but it is less accurate compared to predictive breeding point since simple movements and constant use status are not reflected. However, with these results, the goshawk's habitat can be predicted with reasonable accuracy. In particular, it is necessary to apply precise predictive breeding area data based on habitat modeling results when enforcing an environmental evaluation or establishing a development plan.

• Korean Journal of Environment and Ecology
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• v.32 no.6
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• pp.582-590
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• 2018

Although there are many studies of the effect of climate change on the breeding phenology and community diversity of amphibians, the studies of variations in reproductive population size of individual species according to climate change are still lacking. We examined the effect of climate change on the reproductive population size of Rana huanrenensis and Hynobius leechii, which bred in mountain valleys, by surveying the reproductive population of the two species between 2005 and 2012 and analyzing the correlation between the variation of the outdoor population and the surrounding climate change factors, obtained from a meteorological observatory located at 5.6 km from the study site. The size of the reproductive population of the two species commonly fluctuated with aan pproximately 3.5-year cycle. That of H. leechii, in particular, decreased significantly over eight years. The air temperature tended to more closely relate with the reproductive population size of R. huanrenensis as was the case of the precipitation with that of H. leechii. The yearly mean highest temperature and spring mean temperature variation consistently decreased over the eight years, and the latter was related with the significantly decreased size of H. leechii reproductive population. These results showed that recent climate change directly could affect the reproductive population size of amphibians, particularly H. leechii, which breeds in mountain valleys.

• Journal of Animal Science and Technology
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• v.54 no.1
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• pp.9-14
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• 2012

The purpose of this study was to estimate heritabilities and genetic correlations for reproductive and productive traits and to apply their estimates to selection strategies in a swine population. Reproductive and productive traits considered in this study were number of born alive piglet (NBA), number of weaned piglet (NW), loin eye area (LEA), days to 90 kg (D90KG), back fat thickness (BF), and lean meat content (LEAN). Data were collected from 9,886 litters on 2,447 sows for reproductive traits and 10,181 gilts and boars for productive traits from Jan. 2000 to Dec. 2008 in a swine GGP farm. The statistical model to estimate genetic parameters for considering traits was a multiple traits animal model with including animal and maternal additive effects and litter effects on reproductive traits and animal additive effects on productive traits as random as well as some of fixed effects. For estimating (co) variance components of several random effects, restricted maximum likelihood methodology was used on this assumed model. The estimated heritabilities by animal additive effects and maternal effects were 0.07 and 0.02 for NBA and 0.03 and 0.02 for NW, respectively. Genetic correlation estimate for direct genetic effects between NBA and NW was 0.14. Heritability estimates for direct genetic effects were 0.19, 0.39, 0.36, and 0.43 for LEA, D90KG, BF and LEAN, respectively. The genetic correlation of LEA with LEAN was 0.35. Productive traits were antagonistically correlated with reproductive traits. From these results it is concluded that, if selection is done for strong positive effects of reproductive traits, then this would decline productive performance.

• Korean Journal of Organic Agriculture
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• v.16 no.3
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• pp.321-330
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• 2008

In order to investigate any differences of the characteristics of goat milk according to seasons and individual farms, we analysed and compared the components of fat, protein lactose, total solid, solid-not fat (SNF) and cells of goat milk collected from 8 individual farms between December 2006 and June 2007. Milk fat content has shown higher values in December to March than in other seasons, and SNF appeared especially higher in February. However, lactose content was not different according to seasons. Regional differences of milk components were not big at all either. Milk components from goats were in general similar to cow milk except a little lower fat content, but appeared higher than mare milk. Production of goat milk is in difficulty in aspects of balancing demand and supply due to its seasonal reproductive system. For the future of goat milk industry, it is necessary to develop various products of longer storage life.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.169-175
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• 2002

저장 중 벼의 품질에 영향을 주는 해충 및 미생물의 발생과 성장속도는 곡온과 함수율이 가장 중요한 요인이다. 곡온은 기온의 계절적 변화에 따라 변하게 되며 저장고내의 위치에 따라 다르게 분포된다. 이러한 불 균일한 온도분포는 자연 대류현상을 유발하고 수분이동을 발생시켜, 함수율 증가와 응축현상을 초래하여 벼의 품질을 손상시키게 된다(Keum and Kim, 1991). 해충의 번식은 온도와 매우 밀접한 관계가 있는데 15$^{\circ}C$이하일 때는 매우 느리거나 나타나지 않고, 4$0^{\circ}C$이상일 때는 대개 생존할 수 없다. 그러나, 3$0^{\circ}C$에서는 최대로 번식하게 된다(Chang et al., 1993). (중략)

• Korean Journal of Animal Reproduction
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• v.13 no.3
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• pp.127-133
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• 1989

This study was undertaken to understand development stage of ovary and changes of hormones concentration from February to May in the Israeli carp, Cyprinus carpio. The results obtained in these experiments are as follows ; 1. Serum LH levels began to increase sharphy in March, coinciding with the onset of rapid ovarian development. 2. LH levels were well correlated with changes in gonadosomatic index. 3. Dramatic increase in gonadosomatic index occurred during the months of March. 4. Ripe stage(Stage Ⅴ) rapidly increase in March. 5. Early perinucleolus oocyte radpily develop into late perinucleolus oocytes in March. 6. The vitellogenic phase begins as these late perinucleolus oocytes become transformed into early maturing oocytes through the accumulation of yolk. 7. The cytoplasm completely fills with yolk as oocytes reach the late maturing stage. 8. Changes in the microscopic appearances of the ovaries were well correlated with changes in both gonadosomatic index and macroscopic appearance. 9. It is concluded from these observations that LH plays a major role in sexual maturation of the Israeli carp.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.73-80
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• 2020

Polygonatum stenophyllum Maxim. is a native perennial herb to Korea belonging to family Liliaceae. Although it was removed from the endangered species list, since it inhabits the riverside, it has been threatened with damage to its populations due to frequent disturbances. In order to reveal the basic ecological characteristics of P. stenophyllum, This study was identified the life cycle of the aboveground part and was measured the number of flowers and fruits, which are reproductive organs of P. stenophyllum in riverside in Paju - si during the two years. As a result, aboveground part of P. stenophyllum appeared and grew rapidly until the end of May to about 1m. In early May, two buds per one peduncle were formed up to six pairs per floor. The flowers bloomed in turn from the base of the stem and to the top floor and the blooming occurred when the number of leaves was at least three. Fruits were formed in mid-June and matured by the end of September. The numbers of flowers and fruits were revealed that flowers bloomed in turn from the bottom of the stem to the top floor, the most intensively bloomed in the center part of the stem, and did not bloom from the floor closest to the ground and above the highest 5th node. This basic ecological characteristics of the P. stenophllyum grown in riverside identified in this study will be useful as basic data for their conservation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.63-65
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• 2018

조류는 조석현상에 따라 해수가 이동하기 때문에 일어나는 흐름으로 유향, 유속이 주기적으로 변하며, 일반적으로 반일의 주기를 가지고 있으나 장소에 따라 약 하루의 주기로 유동하는 곳도 있다. 조류에 의한 해수의 이동은 대량의 열량과 수량을 운반 할 뿐만 아니라 그 속에 함유된 각종 성분 및 기타 여러 가지 부유물을 운반함으로써 각종 성분의 분포, 어류의 회유, 번식 등에 관계가 있으며 어류생활에 직접, 간접적으로 많은 영향을 미치고 있다. 본 연구에서는 해수유동의 흐름이 활발한 서해 중부 연안의 관측자료를 이용하여 계절별 조류특성을 파악하였다.

• Landscaping Tree
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• s.110
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• pp.20-22
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• 2009

햇볕이 잘 드는 양지 잔디밭이나 풀밭에 씀바귀들이 한창 피어나는 계절이다. 꽃이 노란 씀바귀나 좀씀바귀, 약간 흰색인 선씀바귀, 종종 그 중간색을 띠는 개체도 보인다. 잔디밭에 나는 것들은 잡초로 뽑아버리기 아까울 정도로 꽃이 아름답다. 이 중 좀씀바귀는 키가 작으면서 포복지로 잘 번식하며 꽃은 물론 잎 모양도 정연하여 적당한 공간에 관상 및 지피용으로 훌륭한 식물이다.