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        검색결과 90

        28.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of the present study was to determine the best model to describe and quantify the changes in live body weight, height at withers, height at rump, body length and chest girth of Holstein cows raised under Korean feeding conditions for 50 months. The five standard growth models namely polynomial linear regression models, regression of growth variables on the first and second-order of ages in days (model 1) and regression of growth variables on age covariates from first to the third-order (model 2) as well as non-linear models were fitted and evaluated for representing growth pattern of Holstein cows raised in Korean feeding circumstances. Nonlinear models fitted were three exponential growth curve models; Brody, Gompertz, and von Bertalanffy functional models. For this purpose, a total of 22 Holstein cows raised in Korea used in the period from April 2016 to May 2020. Each model fitted to monthly growth curve records of dairy cows by using PROC NLIN procedure in SAS program. On the basis of the results, nonlinear models showed the lower root mean square of error (RMSE) for live body weight, height at withers, height at rump, body length and chest girth (12.22, 1.95, 1.55, 4.04, 2.06) with higher correlation coefficiency (R2) values for live body weight, height at withers, height at rump, body length and chest girth (0.99, 0.99, 0.99, 1.00, 1.00). Overall, the evaluation of the different growth models indicated that the Gompertz model used in the study seemed to be the most appropriate one for standard growth of Holstein cows raised under Korean feeding system.
        4,000원
        29.
        2020.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ETc 손실을 보상하는데 필요한 물의 양을 작물 용수 요구량(Crop water requirement, CWR)로 정의되며, ETc 평가는 작물 필요 요구량을 정확하게 정량화하는 데 필요하며, 물 균형 계산에서 중요한 역할을 한다. 토마토와 파프 리카의 실제 관수 요구량(Actual crop water, ACW)이 적절한 CWR인지 평가하였다. 토마토와 파프리카 재배에 적정한 AWC 예측 및 추정을 위하여 온실 내부 환경데이터를 Penman-Monteith을 이용하여 기준 작물 증발산(ET)을 계산한 후, 기준 증발산은 작물 상수(Kc;토마토-1.15, 파프리카-1.05)계수로 조정하였다. 토마토와 파프리카의 CWR과 ACW를 계산하여 비교 평가한 결과 ACW가 CWR을 대체할 수 있지만 파프리카의 ACW는 필요 이상으로 높게 나타났다. 또한, 토마토의 ACW는 1일 100 ~ 1,200 ml이고, 파프리카의 ACW는 1일 100 ~ 500 ml가 적절한 것으로 나타났다. 그러나, 스마트 온실에서 ETc의 정밀도를 높이려면, ETc가 CWR로 변환되고 ACW와 비교하기 위해서 클래스 A팬 설정이 필요하다. 향후 실시간으로 CWR을 측정하기 위한 시뮬레이션 프로그램 연구가 필요하다.
        4,000원
        31.
        2020.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 우라늄 폐촉매 처리 공정에서 발생하는 우라늄 함유 폐기물 대상으로 유리-세라믹 매질 구조의 대형 디스크 소결체 형태로 제작 시, 최종 제작된 소결체의 비등방향 수축 특성 및 변형율 변화를 연구하였다. 본 연구에서는 최대 직경 40 cm를 갖는 다양한 크기 원형 디스크 형태와 원형 디스크의 1/4 크기의 부채꼴 형 소결체를 제작하여 이들의 비등방성 수축 특성을 평가하였다. 60 MPa 압력하에서 만들어지는 성형체는 소결 시 성형체의 크기 및 형태에 관계없이 높은 등방성 수축하였다. 제조된 전체 소결체에 대한 비등방성율은 평균 1.6%이었고 이때 평균 부피 감용율은 37.4% 이었다. 이러한 결과 로부터 국내에서 발생한 우라늄 폐촉매를 처리하기 위한 공정에서 발생하는 우라늄 함유 폐기물은 대형 디스크 형태의 유리-세라믹 매질 형태로 고형화함으로써 높은 안정성과 부피감용 효과를 가지며 200 L 드럼에 포장될 수 있음이 확인되었다.
        4,200원
        34.
        2019.04 구독 인증기관·개인회원 무료
        The Nitidulidae includes 10 subfamilies and over 350 genera and 4500 species and is the largest family in Cucujoidea. We place the enigmatic subfamily Calonecrinae into the internal relationship of Nitidulidae, a comprehensive molecular phylogenetic analysis was performed using five gene regions (COI, 28s, CAD, H3, Wingless) for 80 taxa. We included 73 ingroup taxa representing nine of the ten currently recognized subfamilies of Nitidulidae and 7 outgroups. The phylogenetic results are consistent with prior molecular studies, that include a polyphyletic Nitidulinae with the inclusion of Meligethinae and Cillaeinae and that the Calonecrinae is sister taxon to Epuraeinae. Ancestral state reconstruction of feeding behavior indicates that stem group nitiduilds were most probably sap-feeding with transitions to other feeding types independently derived multiple times.
        35.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the characteristics of obesity induced by a high-fat diet (HD) over 13 weeks in Rhbdf2 gene knockout (KO) mice. Forty 7-week-old Rhbdf2 wild and KO mice were used and the mice were divided into 4 groups: Wild-ND (n=10, Rhbdf2 wild mice, normal diet (ND)), Wild-HD (n=10, Rhbdf2 wild mice, HD), KO-ND (n=10, Rhbdf2 KO mice, ND) and KO-HD (n=10, Rhbdf2 KO mice, HD). The relative epididymal fat weight in KO-HD was significantly increased compared with that in KO-ND (P<0.01). The relative liver and spleen weights in KO-HD were decreased compared with those in Wild-HD (p < 0.05) and KO-ND (p < 0.01). The mRNA expression of SOD1 in KO-ND was significantly reduced compared with that in Wild-ND (p < 0.05). In Wild-ND and HD, the mRNA expressions of TNF-α and IL-6 in epididymal fat were significantly increased compared with those in KO-ND and HD (p < 0.01). A significant increase of TNF- α and IL-6 mRNA expression was observed in KO-HD compared with KO-ND (p < 0.01). These results indicated that Rhbdf2 genes may regulate high fat diet-induced obesity damage by anti-inflammatory and anti-oxidative roles in fat tissue of mice.
        4,000원
        39.
        2018.10 구독 인증기관·개인회원 무료
        The hypopharyngeal gland (HPG) of the honeybee worker produces royal jelly (RJ) and has a developmental cycle closely related to the division of labor. In this study, we investigated to compare the HPG acini diameter of differently aged worker bees with high royal jelly producing colony (HRC) or less producing colony (LRC). Additionally, we also evaluated whether the fresh weight of the head is a reliable indicator of the developmental status of HPG. The HRC showed a significantly higher RJ production about two-times as compared with those of the LRC. We measured the HG-diameters on days 1, 3, 6, 9, 12, 15. The microscopic analysis revealed that the acini size of the HRC was significantly larger than the LRC. In addition, the acini diameter of HRC was 15% longer than the LRC on the first day after emerging. It was shown that the fastest development during 3 days which is preparing for nurse the brood. The HPG acini diameters increased in both colonies in a similar fashion until day 12 and then decreased. We also compared the fresh head weight of the experimental colonies, differences were similar to the development of HPG. Therefore, high royal jelly production may have a positive correlation between HPG acini size and the fresh head weight.
        40.
        2018.10 구독 인증기관·개인회원 무료
        Geminiviruses are plant-infecting viruses with monopartite or bipartite single-stranded circular DNA genomes. They are known to be mediated by insects such as whiteflies, treehoppers, leafhoppers or aphids and can cause devastating plant diseases in a wide range of economically significant crops worldwide. In Korea, occurrence of geminiviruses were reported officially after the 2000s. Although Honeysuckle yellow vein virus (HYVV) and Sweet potato leaf curl virus (SPLCV) were identified from honeysuckle and sweet potato in 2004 and 2006 respectively, these viruses did not spread and cause much concern for geminiviruses. In 2008, Tomato yellow leaf curl virus (TYLCV) that has caused severe tomato production loss in many subtropical and tropical countries was first reported in tomato plants cultivated in Tongyeong. TYLCV rapidly spread through the country and has been continuously reported from tomato cultivating areas in Korea. In addition to TYLCV, Tobacco leaf curl virus and Sweet potato golden vein associated virus have occurred. In recent years, new geminiviruses including Papaya leaf curl Guangdong virus (PaLCGdV) and Euphorbia leaf curl virus (EuLCV) have been introduced. Newly emerging geminiviruses from tropical and subtropical countries are due to increased demand for various fruits and vegetables, and climate change. In addition, there are reports that some geminiviruses including TYLCV can be transmitted by infected seeds. Therefore it is important to study on epidemiology of virus introduction and spread among the countries and within country.
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