This study was carried out to investigate the seasonal effect on the recovery rate of embryos in donors and on the conception rate in recipients following embryo transfer. The results obtained from this experiment were summarized as follows: 1. The ovulation point in winter and summer was 28.6 and 28.6, respectively. There was no difference in ovulation point between two seasons. More embryos recovered in the winter (27,0) than the summer (20.9). 2. The number of CL, unruptured follicle, hemorrhagic follicle, young born and pregnancy rate in the winter were 6.0,4.8,1.5,1.8 and 75%, and those in the summer were 2.9,5.7, 3.8, 2.2 and 46.7%, respectively. The rate of synchronization of recipients in the winter showed better results than that in the summer.

This study was carried out to investigate the effects of different cutting times at 0, 10 and 20 days after lodging on the percentage of dead plants and bare ground, live and dead matter build-up, and botanical composition of orchardgrass dominated pastur

場에 林間栽培함에 있어서 閉度의 多少가 牧草의 生育 및 收量에 미치는 影響을 究明코자 리기데타 人工造林地의 閉度를 0(露光區), 25, 50, 75%로 調節하여 Orchard grass를 栽培하였던 바 그 結果는 다음과 같다. 1 林地內의 Orchard grass의 葉面積은 各 刈取時期 모두 閉度 25, 0, 50, 75%區의 順位이며 特히 閉度 25%區는 0%區에 비하여 有意的인 增加傾向 이었다. 2. Orchard grass의 草長은 閉度가 높을수록

본(本) 연구(硏究)는 고온기(高溫期) 초지(草地)의 예취관리(刈取管理)에 관(關)한 연구(硏究)로서 여름철 고온기간중(高溫期間中) 예취시기(刈取時期)와 예취(刈取)높이가 tall fescu 우점초지(優占草地)의 목초고사(牧草枯死), 잡초발생(雜草發生), 재생(再生)과 저장탄수화물함량(貯藏炭水化物含量) 및 수량(收量)에 미치는 영향을 구명(究明)하여 고온기(高溫期)의 적절한 예취방법(刈取方法) 모색하기 위해 실시(實施)되었다. 본(本) 시험(試驗)은 3

In this study, we analyzed the relationships between weather factors and photosystem II activity (Fv/Fm), as a measure of photochemical efficiency, in three cool-season turfgrasses commonly planted on golf courses in Jeju, South Korea: perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), and creeping bentgrass (Agrostis palustris Huds.). In all three turfgrasses, Fv/Fm was higher during late summer than during early summer. However, in late summer, Fv/Fm was significantly lower in perennial ryegrass than in the other two species. In early summer, Fv/Fm in perennial ryegrass and Kentucky bluegrass was positively correlated with mean low temperature and extreme minimum temperature, whereas, in late summer, this parameter in Kentucky bluegrass and creeping bentgrass was positively correlated with relative humidity, and in creeping bentgrass was negatively correlated with mean high temperature, mean low temperature, and extreme maximum temperature. These results indicate that raising low temperatures is favorable for perennial ryegrass and Kentucky bluegrass in early summer, whereas, in late summer, the lowering of high temperatures proves to be beneficial for creeping bentgrass, and raising relative humidity is conducive to the growth of Kentucky bluegrass and creeping bentgrass. These findings will contribute to improving the selection and management of turfgrasses on golf courses and sports fields.

To compare the vitality among cool-season turfgrasses under summer weather conditions and to obtain information to improve the management of turfgrasses in golf courses and sports fields., the chlorophyll fluorescence of three cool-season turfgrasses commonly planted on golf courses in the Jeju area was measured. The turfgrasses were perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), and creeping bentgrass (Agrostis palustris Huds.). In perennial ryegrass and Kentucky bluegrass, the chlorophyll index was low in early summer and high in late summer. In creeping bentgrass, it remained low throughout the study. Fo tended to be low in the early summer and high in late summer in the three turfgrasses. However, the difference in Fo between late summer and early summer was markedly higher in perennial ryegrass than in Kentucky bluegrass or creeping bentgrass. Fm tended to be low in early summer and high in late summer, without obvious differences among the three turfgrasses. Fv/Fm, a measure of photochemical efficiency, was also low in early summer and high in late summer in the three turfgrasses. However, Fv/Fm in late summer was mostly higher in Kentucky bluegrass and creeping bentgrass than in perennial ryegrass, indicating that the former are more resistant to the high temperature and humidity of late summer. Furthermore, Kentucky bluegrass had a high chlorophyll index in late summer and would be most resistant to the harsh conditions of late summer.

In meteorological data, various studies are being conducted to improve the prediction performance of rainfall with irregular patterns, unlike temperature and solar radiation with certain patterns. Especially in the case of the short-term forecast model for Dong-Nae Forecasts provided by the Korea Meteorological Administration (KMA), forecast data are provided at 6-hour intervals, and there is a limit to analyzing the impact of disasters. In this study, Hydrological Quantitative Precipitation Forecast (HQPF) information was generated by applying the machine learning method to Local ENsemble prediction system (LENS), Radar-AWS Rainrates (RAR), AWS and ASOS observation data and Dong-Nae Forecast provided by the KMA. Through the preprocessing process, the temporal and spatial resolutions of all the data were converted to the same resolution, and the predictor of machine learning was derived through the factor analysis of the predictor. Considering the processing speed and expandability, the XGBoost method of machine learning was applied, and the Probability Matching (PM) method was applied to improve the prediction accuracy of heavy rainfall. As a result of evaluating the HQPF performance produced for 14 heavy rainfall events that occurred in 2020, it was found that the predicted performance of HQPF was improved quantitatively and qualitatively.

Water and sediment qualities were investigated in the Oncheon Stream and at the Wondong bridge of the Suyoung River, during the summer rainy season, 2019. Dissolved oxygen (DO) showed the lowest levels at 4.7 and 5.0 m/L, and biogeochemical oxygen demand (BOD) showed the highest at 5.3 mg/L downstream where the tributary flows into the main river. Chemical oxygen demand (COD) increased from 2.0 to 5.9 mg/L on average as it flowed downstream, The COD/BOD ratio decreased gradually as it flowed downstream, reaching 1.0. However, COD/BOD ratio at the Wondong bridge was 5.8-22.2, indicating that easily biodegradable and non-biodegradable organic matter flows into the Oncheon Stream and Suyoung River, respectively. Total nitrogen (T-N) / total phosphorus (T-P) ratio tended to decrease from 72 to 21 as it flowed downstream, measuring 71 to 86 at the Wondong bridge. The water quality index (WQI) generally improved better than grade IV after heavy rainfalls. However, DO and T-P were the parameters that deteriorated the WQI. Ignition loss (IL), COD, T-N, and T-P of sediments had distribution of 1.44 ± 1.01%, 0.35 ± 0.16%, 43 ± 63 mg/kg, and 10.9 ± 21.9 mg/kg, respectively. These were several times lower than the annual averages of IL, T-N, and T-P in 2017 before the dredging project was conducted in the first half of 2018.

The detailed characteristics of fog over South Korea were analyzed using the three-years quality controlled (QC) 237 visibility meter data operated by Korea Meteorological Administration. The fog (dense fog: DFog) frequency varies greatly with season and geographic location. The fog frequency at inland is highest in autumn, but at the West Coast in spring and summer. Fog occurs frequently from spring to autumn in the mountainous regions. Unlike the fog, the DFog is mostly prevalent in summer at land, mountain, and coastal regions. The large coefficients of variation of fog and DFog at the three regions and four seasons indicate that the locality of fog over South Korea is very high. The formation and dissipation (FaD) of fog show strong diurnal variations irrespective of geographic location and season, strongest at inland and weakest at sea. Fog usually occurs from night to sunrise and dissipates from early morning to late morning. The maximum FaD time of fog show seasonal variation with the seasonal change in solar elevation angle. The frequency of fog is inversely proportional to the duration time, mostly less than 3 hours regardless of season and geographic location. Also, the duration of DFog is mostly within 1-3 hours.

비탈면 붕괴의 한 요소로 동절기 및 해빙기 과정에서 동결-융해에 따른 풍화, 수축-팽창 등의 영향으로 비탈면 안정성에 영향을 미치는 것으로 알려져 있으며, 실제 국내외에서 해빙기 시기에 비탈면 붕괴사고가 빈번히 발생하고 있다. 본 연구에서는 해빙기 비탈면의 안전 확보를 위하여 해빙기 비탈면 유지관리 방안을 제시하였다. 외관조사 및 자료조사를 통한 상세 점검을 바탕으로 고도화된 위험성 평가 여부를 결정하고, 위험성 평가에서도 위험성이 높다고 판단되는 경우, 전기비저항 등을 통해 위험단면을 선정하여 실시간 모니터링을 경제적으로 실시할 수 있도록 유지관리 프로세스를 계획하였다.

This study investigated the relationship between heat-related illnesses obtained from healthcare big data and daily maximum temperature observed in seven metropolitan cities in summer during 2013~2015. We found a statistically significant positive correlation (r = 0.4~0.6) between daily maximum temperature and number of the heat-related patients from Pearson's correlation analyses. A time lag effect was not observed. Relative Risk (RR) analysis using the Generalized Additive Model (GAM) showed that the RR of heat-related illness increased with increasing threshold temperature (maximum RR = 1.21). A comparison of the RRs of the seven cities, showed that the values were significantly different by geographical location of the city and had different variations for different threshold temperatures. The RRs for elderly people were clearly higher than those for the all-age group. Especially, a maximum value of 1.83 was calculated at the threshold temperature of 35℃ in Seoul. In addition, relatively higher RRs were found for inland cities (Seoul, Gwangju, Daegu, and Daejeon), which had a high frequency of heat waves. These results demonstrate the significant risk of heat-related illness associated with increasing daily maximum temperature and the difference in adaptation ability to heat wave for each city, which could help improve the heat wave advisory and warning system.

Recently, the slope failure, which is frequently happened in Ice-melting season, attracts attention in South Korea. The increasing trend in frequency of freezing-thawing process has regarded as major reason of slope failure. However, the time and check level are not reflected at the safety assessments and inspection guidelines. Therefore, the characteristics of slope in ice-melting season should be considered to improve the slope stability in ice-melting season. The purpose of this study is to evaluate the influence of the potential risk factors on the slope stability for development of the slope checklist reflecting the timing and check level based on the slope inspection checklist which is provided by the recent research.

In this study, daily precipitation data and daily average temperature data of meteorological observatories in Daegu, Busan, Daejeon, Seoul, Mokpo, and Gwangju cities inland and offshore were analyzed by using moving average method. Were compared. Overall, summarizing changes in precipitation and temperature over the 24 seasons, precipitation and temperature in all six stations increased compared to the past 1960s. In the case of precipitation, precipitation increased at the end of July and early August, whereas precipitation in April, September and early October decreased. In the case of temperature, especially in February, the temperature increased, and in Mokpo, the temperature from August to December showed a general decline. Changes in precipitation and temperature due to seasons in the 24 seasons affect agriculture and our everyday life, and further research is needed to determine how these changes will affect agricultural water supply, crop growth and daily life. The results of this study can be useful.

In this study, the runoff characteristics of the non-rainfall period were examined using daily rainfall data from 1977 to 2017 and the data of runoff into the dam. Results showed that, the mean runoff decreases with longer non-rainfall periods in the Andong dam basin. The correlation coefficient between non-rainfall days and average runoff reaches 0.85. The results of the analysis of the runoff characteristics during the non-rainfall period, based on the preceding rainfall of Andong dam are as follows. The runoff characteristics of the entire non-rainfall period, shows that, for a rainfall of 1.0 mm or less, the runoff height was larger than the rainfall size and the base runoff larger. The correlation between the antecedent rainfall and runoff height was reached as high as 0.9864 in the 30 ~ 50 mm interval of the antecedent rainfall period, and this is the interval where the linearity of rainfall and runoff was at its maximum in the Andong dam basin. The correlation between the antecedent rainfall and the runoff height reached 0.92 for rainfalls of 100.0 mm. However, for rainfalls of 100.0 mm greater, the correlation between the antecedent rainfall and runoff height during the rainfall period was 0.64, which is relatively small. In this study, we investigated the runoff characteristics of the rainfall period in the Andong dam watershed. As a result, it was confirmed that the mean runoff decreased with rainfall duration. The linearity was found to be weak for rainfall events greater than 100.0 mm. The results of this study can be used as data for water balance analysis and for formulating a water supply plan to establish water resource management of Andong dam.

Background : Rehmannia glutinosa L. that is a perennial plant belonging to the family Scrophulariaceae is one of the most popular local income crops. Recently, the cultivation area of Chungnam (2017) accounts for 50.5% (106 ha) of the whole country. In July and August, which is the off-season at the highest price of R, glutinosa L. This experiment was carried out to develop early harvest cultivation technology for the improve farm income. Methods and Results : In order to investigate the growth characteristic and yield of R, glutinosa L. by using the rhizome of 'Tokang' were transplanted four times at intervals of 10 days from mid-March to mid-April 2017 and 2018. Growth characteristics of the above and under ground part were investigated by 3 repetitions for 10 ea harvested in mid-July. Regression analysis was performed on the relationship between the planting time and fresh root weight. The highest emergence rate was 88.7% in the mid-March, and the highest above ground part growth was observed in the plant height, leaf number, leaf length, leaf width, and fresh leaves weight. The number of days to flowering tended to be shortened to 60, 53, 52, and 49 days from the mid-March to the mid-April. The growth of underground part was also highest in mid-March and the total root weight per 10 a was also 1,127.4 ㎏ in mid-March. The faster the planting time, the higher the yield. The results of the linear regression on the roots weight according to the planting time showed that there was a negative correlation relation between the planting time, the marketable roots weight, rhizome weight and total roots weight. Conclusion : The total roots weight improved by 80% in the mid-March than mid-April. Therefore, mid-March is considered optimal planting time for off-season production of R. glutinosa L.

We developed new two-rowed covered barley ‘Gwangmaeg’ superior to ‘Hopum’ that has been widely cultivated in Korea for using beer-materials. ‘Gwanngmaeg’ was related from the line named as ‘Iksan149’ in 2010 after yield trials test in conducted for three years from 2008. And then it was registered to ‘Plant protection right, No. 5847’ in 2016 after field experiment by KSVS(Korea Seed & Variety Service). ‘Gwangmaeg’ has distinct characteristics in winter type (IV) and mid-tall culm length which makes reduce damage by off-season heading and lodging comparing to those of ‘Hopum’. ‘Gwangmaeg’ have characteristics of cold tolerance and disease resistance to BaYMV(Barley yellow mosaic virus) and Net blotch(Pyrenophora teres). Yield of ‘Gwangmaeg’ was about 611kg/10a and 524kg/10a in upland and paddy field condition, respectively, which higher 2-4% than ‘Hopum’, however, it has no significant difference. In quality examination for beer usage, ‘Gwangmaeg’ has lager grain and higher assortment ratio than those of ‘Hopum’. In malt quality, ‘Gwangmaeg’ showed higher and better quality in malt extract rate and diastatic power than those of ‘Hopum’. ‘Gwangmaeg’ would be suitable for the area above –4℃ of daily minimum temperature in January in Korean peninsula.

Concrete made with ground granulated blast-furnace slag(GGBS) has many advantage, including improved durability, workability and economic benefits. GGBS concrete is that its strength development is considerably slower under standard 20°C curing conditions than that of portland cement concrete, although the ultimate strength is higher for same water-binder ratio. GGBS is not therefore used in application where high early age strength is required. In this study, to overcome the limitation of the initial strength decrease due to the use of slag, the slag substitution rate was changed to 30% under the low temperature curing temperature condition and the slag used concrete composition with the same or higher strength performance as OPC(Ordinary Portland Cement).

The purpose of this study is to investigate the differences fatty acids and hormonal parameters in the spawning and non-spawning season between the diploid and induced triploid Far Eastern catfish, Silurus asotus. The measured triploids were produced by cold shock for 50 min at 4℃ in May 2014, the spawning season of diploid was in May, and the nonspawning season was designated in January. Estradiol and testosterone and gonadosomatic index of diploid were higher than those of induced triploid in spawning season (P<0.05), and those of diploid in spawning season were higher than nonspawning season. On the other hand, thyroid stimulating hormone and thyroxine of induced triploid were higher than those of diploid in spawning season (P<0.05). Erythrocyte count of diploid was higher than that of induced triploid in spawning season and non-spawning seasons. Mean corpuscular volume and mean corpuscular hemoglobin of induced triploid were higher than those of diploid in both seasons (P<0.05). Percentages of total saturated fatty acids and n-3 polyunsaturated fatty acids of induced triploid were higher than those of diploid in spawning season, but those of diploid were higher in non-spawning season (P<0.05). Percentages of total mono unsaturated fatty acids and total n-6 polyunsaturated fatty acids of diploid were higher than those of induced triploids in spawning season, while those of induced triploid in non-spawning season were higher (P<0.05). Therefore, induced triploids in the spawning season tend to concentrate on growth and lipid-synthesization, whereas, diploids concentrate on reproduction and gonadal maturation rather than on growth. In non-spawning season, growth and lipid- synthesization were not significantly different between diploid and induced triploid.