• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.2
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• pp.145-152
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• 2002

To compare the Carbon metabolic response to high temperature stress in Zoysiagrass [Zoysia matrella (L.) Merr.] and Creeping bentgrass (Agrostis palustris Huds) with respect to heat tolerance, C metabolites were determined from April to September. Sampling was carried out on an established golf course (Muan Country Club, Chonnam, Korea). Shoot mass(g Dry weight per hole cup) of creeping bentgrass started to decrease from June and recovered from August whereas that of zoysiagrass was less varied. Chlorophyll content in creeping bentgrass was significantly higher than zoysiagrass until July, and then decreased by 43% from July to August. Zoysiagrass contained higher soluble sugar than creeping bentgrass throughout experimental period. Soluble sugar in zoysiagrass increased about 58% from April to May, and less varied until August. Soluble sugar in creeping bentgrass slightly increased until July and sharply decreased at August. Starch concentration in zoysiagrass continuously decreased to September after a significant increase from April to May. A remarkable fluctuation in both starch and fluctuation concentration was observed between June and August showing high accumulation for June to July and high degradation for July to August. These results suggest that through creeping bentgrass suffers much severely from high temperature stress than zoysiagrass especially June to August. An active accumulation and degradation in nonstructural carbohydrate in creeping bentgrass during this period might be associated with heat stress.

• Journal of Animal Science and Technology
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• v.53 no.2
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• pp.155-160
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• 2011

Present experiment was carried out to determine maintenance energy requirements for growing Hanwoo steers. Six Hanwoo steers (BW = $180.6{\pm}3.1$ kg) were used in two 3 ${\times}$ 3 latin square design with three different energy intake levels; TDN 1.70 kg (Low), 2.05 kg (Medium), 2.80 kg (High), respectively, based on the Korean Feeding Standards. Each period lasted 18 days including a 14-day adaptation and a 4-day measuring period. The steers were in the head hood chamber system (one cattle per chamber) during each measuring time to measure heat and methane production for 1 day. Dry matter intake was 2,058, 3,256 and 3,881 g/day for Low, Medium and High TDN, respectively. Increase in energy intake did not affect digestibilities of dry matter, crude protein, crude fiber, crude fat, NDF, ADF and nitrogen-free extract. Gross energy intake averaged 180.21, 292.74 and 337.15 kcal/$BW^{0.75}$ for Low, Medium and High TDN, respectively. Energy loss was 28.7% in feces and 2.1% in urine of gross energy intake. Further, energy loss from methane produced during rumen fermentation was 6~8.3%, while body heat loss averaged 34~60%. Intercept of regression equation between ME intake and retained energy indicated that the energy requirement was 109.84 kcal ME/$BW^{0.75}$.

• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.100-104
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• 1997

A new baekji(Angelica dahurica Bentham et Hooker) variety, Baekji l, was developed through a pure line selection at the Gyeongbug Provincial RDA during the period of 1990 to 1995. The variety was characterized to have high plant height. Long root length and large root diameter as compared with a check varicty of Bonghwa baekji but emergence date, flowering date and leaf number of Baekji l was similar to that of the check variety, and it was also more tolerant to nematode and heat stress. Peeled root color of Backji l was yellowbrown but number of the lateral root of the variety was greater. The dried-root yield of Baekji l in yield trial, regional adaptation trial and farmer's field trial was always $21\sim31%$ higher than that of the check variety.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.1
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• pp.115-127
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• 2018

This study aims to propose management strategies of ventilation paths for improving urban thermal environments. For this purpose, Gimhae-si in Gyeongsangnamdo was selected as a study area. We analyzed hot spots and cool spots in Gimhae by using Landsat 8 satellite image data and spatial statistical analysis, and finally derived the vulnerable areas to thermal environment. In addition, the characteristics of ventilation paths including wind direction and wind speed were analyzed by using data of the wind resource map provided by Korea Meteorological Administration. As a result, it was found that a lot of hot spots were similar to those with weak wind such as Jinyoung-eup, Jillye-myeon, Juchon-myeon and the downtown area. Based on the analysis, management strategies of ventilation paths in Gimhye were presented as follows. Jinyoung-eup and Jillye-myeon with hot spot areas and week wind areas have a strong possibility that hot spot areas will be extended and strengthened, because industrial areas are being built. Hence, climate-friendly urban and architectural plans considering ventilation paths is required in these areas. In Juchon-myeon, where industrial complexes and agricultural complexes are located, climate-friendly plans are also required because high-rise apartment complexes and an urban development zone are planned, which may induce worse thermal environment in the future. It is expected that a planning of securing and enlarging ventilation paths will be established for climate-friendly urban management. and further the results will be utilized in urban renewal and environmental planning as well as urban basic plans. In addition, we expect that the results can be applied as basic data for climate change adaptation plan and the evaluation system for climate-friendly urban development of Gimhye.

• Journal of Animal Science and Technology
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• v.54 no.1
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• pp.15-22
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• 2012

This study was conducted to investigate the effects of grain sources on the ruminal methane production in Hanwoo steers. Six Hanwoo steers (BW = 614.4 ${\pm}$ 8.3 kg) were fed, on a DM basis (TDN 6.91 kg), 10% rice straw and 90% barley or corn based concentrate, respectively, according to Korean Feeding Standards (Hanwoo). Each period lasted 18 days including a 14-day adaptation and a 4-day measuring period. The steers were in the ventilated hood-type respiration chamber system (one cattle per chamber) during each measuring period to measure heat and methane production for 1 day. Nutrient intake and digestibility were not affected by steer fed grain sources. Methane concentration was not affected by steer fed either barley or corn-based concentrate, respectively (0.022% vs. 0.025%). Methane production was greater by steers fed corn than those fed barley (119.3 g/day vs. 139.4 g/day). This result indicated that methane emission factor by maintenance energy requirement for the late fattening Hanwoo fed corn was higher than the steers fed barley (43.6 kg/head/year) vs. corn (50.9 kg/head/year). Methane conversion rate (Ym) was 0.04 Ym and 0.05 Ym for barley and corn, respectively.

• Journal of Animal Science and Technology
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• v.53 no.2
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• pp.161-169
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• 2011

Methane production during anaerobic fermentation in the rumen represents an energy loss to the host animal and induces emissions of greenhouse gases in the environment. Our study focused on comparison in methane production from growing Korean native steers fed different grain sources. Six Hanwoo steers (BW = $180.6{\pm}3.1$ kg) were fed, on a DM basis (TDN 2.80 kg), 40% timothy and 60% barley concentrate (Barley) or corn concentrate (Corn), respectively, based on the Korean Feeding Standards. Each period lasted 18 days including a 14-day adaptation and a 4-day measuring times. The steers were in the head hood chamber system (one cattle per chamber) during each measuring time to measure heat and methane production per day. Different grain sources did not affect digestibilities of dry matter, crude protein, crude fiber, crude fat, NDF, ADF and nitrogen-free extract. The mean methane concentrations per day were 202.0 and 177.1 ppm for Barley and Corn, respectively. Methane emission averaged 86.8 and 77.7 g/day for Barley and Corn, respectively. Methane emission factor by maintenance energy requirement for the growing steers fed barley based concentrate was higher than the steers fed corn based concentrate (Barley vs. Corn, 31.7 kg $CH_4\;head^{-1}\;yr^{-1}$ vs. 28.4 kg $CH_4\;head^{-1}\;yr^{-1}$). Thus, methane conversion rate was 0.065 (6.5%) and 0.055 (5.5%) for Barley and Corn, respectively.

• Journal of Embryo Transfer
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• v.20 no.2
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• pp.185-190
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• 2005

This study was performed to investigate the effects of multiple superovulation and parity on embryo production in Hanwoo cows. Donors were superovulate 4 times $1\~2$ months interval and inserted CIDR plus (with the capsule of estradiol benzoate 10mg) on Day 10 from standing heat for 9 days and injected 2.5ml FSH (Antorin R-10) 2 times in a day on 6th day to 10th day from insertion of CIDR and the doses of FSH were decreasing 0.5ml on every 2 times. On 3th day of FSH injection, 25ml $PGF_2{\alpha}$ were injected i.m. and on 4th day, CIDR was removed. After 2 days from removing CIDR, AI was performed 2 times 12 hour apart with 2 straws of Korean Proved frozen Semen and simultaneously 200ug/ml GnRH was injected and embryos were recovered on 7th day from Al. The response rates of superovulated donors were $85.7\%,\;90.5\%,\;62.5\%,\;100\%$ from 1 to 4 times of superovulation, respectively. There were significant differences among No. of superovulation times (P<0.05). The results of transferable embryos were 3.7, 3.4, 3.4, 5.7 from 1 to 4 times of superovualtion, respectively. There were no differences among No. of superovulation times. The results of transferable embryos were 2.5, 3.0, 5.3, 3.0, 3.4 form heifer, first born to 4 the born, respectively. There were significant differences among the parities of donors (P<0.05). These results suggested that even 4 times of superovulations of Hanwoo donors could be able to recover transferable embryos, it might be used the donors maximally and improved the adaptation of embryo transfer to farms safely.

• Journal of Korean Society of Forest Science
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• v.109 no.3
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• pp.259-270
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• 2020

Extreme weather events, such as heat and drought, have occurred frequently over the past two decades. This has led to continuous reports of cases of forest damage due to physiological stress, not pest damage. In 2014, pine trees were collectively damaged in the forest genetic resources reserve of Sogwang-ri, Uljin, South Korea. An investigation was launched to determine the causes of the dieback, so that a forest management plan could be prepared to deal with the current dieback, and to prevent future damage. This study aimedto 1) understand the topographic and structural characteristics of the area which experienced pine tree dieback, 2) identify the main causes of the dieback, and 3) predict future risk areas through the use of machine-learning techniques. A model for identifying risk areas was developed using 14 explanatory variables, including location, elevation, slope, and age class. When three machine-learning techniques-Decision Tree, Random Forest (RF), and Support Vector Machine (SVM) were applied to the model, RF and SVM showed higher predictability scores, with accuracies over 93%. Our analysis of the variable set showed that the topographical areas most vulnerable to pine dieback were those with high altitudes, high daily solar radiation, and limited water availability. We also found that, when it came to forest stand characteristics, pine trees with high vertical stand densities (5-15 m high) and higher age classes experienced a higher risk of dieback. The RF and SVM models predicted that 9.5% or 115 ha of the Geumgang Pine Forest are at high risk for pine dieback. Our study suggests the need for further investigation into the vulnerable areas of the Geumgang Pine Forest, and also for climate change adaptive forest management steps to protect those areas which remain undamaged.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2014.10a
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• pp.1-24
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• 2014

This study uses geo-spatial crop modeling to quantify the biophysical impact of weather extremes. More specifically, the study analyzes the weather extreme which affected maize production in the USA in 2012; it also estimates the effect of a similar weather extreme in 2050, using future climate scenarios. The secondary impact of the weather extreme on food security in the developing world is also assessed using trend analysis. Many studies have reported on the significant reduction in maize production in the USA due to the extreme weather event (combined heat wave and drought) that occurred in 2012. However, most of these studies focused on yield and did not assess the potential effect of weather extremes on food prices and security. The overall goal of this study was to use geo-spatial crop modeling and trend analysis to quantify the impact of weather extremes on both yield and, followed food security in the developing world. We used historical weather data for severe extreme events that have occurred in the USA. The data were obtained from the National Climatic Data Center (NCDC) of the National Oceanic and Atmospheric Administration (NOAA). In addition we used five climate scenarios: the baseline climate which is typical of the late 20th century (2000s) and four future climate scenarios which involve a combination of two emission scenarios (A1B and B1) and two global circulation models (CSIRO-Mk3.0 and MIROC 3.2). DSSAT 4.5 was combined with GRASS GIS for geo-spatial crop modeling. Simulated maize grain yield across all affected regions in the USA indicates that average grain yield across the USA Corn Belt would decrease by 29% when the weather extremes occur using the baseline climate. If the weather extreme were to occur under the A1B emission scenario in the 2050s, average grain yields would decrease by 38% and 57%, under the CSIRO-Mk3.0 and MIROC 3.2 global climate models, respectively. The weather extremes that occurred in the USA in 2012 resulted in a sharp increase in the world maize price. In addition, it likely played a role in the reduction in world maize consumption and trade in 2012/13, compared to 2011/12. The most vulnerable countries to the weather extremes are poor countries with high maize import dependency ratios including those countries in the Caribbean, northern Africa and western Asia. Other vulnerable countries include low-income countries with low import dependency ratios but which cannot afford highly-priced maize. The study also highlighted the pathways through which a weather extreme would affect food security, were it to occur in 2050 under climate change. Some of the policies which could help vulnerable countries counter the negative effects of weather extremes consist of social protection and safety net programs. Medium- to long-term adaptation strategies include increasing world food reserves to a level where they can be used to cover the production losses brought by weather extremes.