The Impact of Observation Systems on Medium-Range Weather Forecasting in a Global Forecast System

Seung-On Hwang,홍성유 한국기상학회 2012 Asia-Pacific Journal of Atmospheric Sciences Vol.48 No.2

To investigate the impact of various types of data on medium-range forecasts, observing system experiments are performed using an assimilation algorithm based on the National Centers for Environmental Prediction (NCEP)/Department of Energy (DOE)reanalysis system. Data-denial experiments for radiosonde, satellite,aircraft, and sea surface observations, and selected data experiments for radiosonde and surface data, are conducted for the boreal summer of 1997 and the boreal winter of 1997/1998. The data assimilation system used in this study is remarkably dependent on radiosonde data,which provides information about the three-dimensional structure of the atmosphere. As expected, the impact of radiosonde observations on medium-range forecasts is strongly positive over the Northern Hemisphere and tropics, whereas the satellite system is most beneficial over the Southern Hemisphere. These results are also found in experiments simulating historical changes in observation systems. Over the tropics, assimilation without radiosonde observations generates unbalanced analyses resulting in unrealistic forecasts that must be corrected by the forecast model. Forecasts based on analysis from the observation data before the era of radiosonde observation are found to be less meaningful. In addition, the impacts on forecasts are closely related to the geographical distribution of observation data. The memory of observation data embedded in the analysis tends to persist throughout forecasts. However, cases exist where the effect of forecast error growth is more dominant than that of analysis error, e.g.,over East Asia in summer, and where the deficiency in observations is supplemented or the imbalance in analysis is adjusted by the forecast model during the period of forecasts. Forecast error growth may be related to the synoptic correction performed by the data assimilation system. Over data-rich areas, analysis fields are corrected to a greater extent by the data assimilation system than are those over data-poor areas, which can cause the forecast model to produce more forecast errors in medium-range forecasts. It is found that even one month per season is sufficient for forecast skill verification in data impact experiments. Additionally, the use of upper-air observations is found to benefit areas that are downstream of observation data-rich areas.

Podophyllotoxin Induces ROS-Mediated Apoptosis and Cell Cycle Arrest in Human Colorectal Cancer Cells via p38 MAPK Signaling

( Seung-On Lee ),( Sang Hoon Joo ),( Ah-won Kwak ),( Mee-hyun Lee ),( Ji-hye Seo ),( Seung-sik Cho ),( Goo Yoon ),( Jung-il Chae ),( Jung-hyun Shim ) 한국응용약물학회 2021 Biomolecules & Therapeutics(구 응용약물학회지) Vol.29 No.6

Podophyllotoxin (PT), a lignan compound from the roots and rhizomes of Podophyllum peltatum, has diverse pharmacological activities including anticancer effect in several types of cancer. The molecular mechanism of the anticancer effects of PT on colorectal cancer cells has not been reported yet. In this study, we sought to evaluate the anticancer effect of PT on human colorectal cancer HCT116 cells and identify the detailed molecular mechanism. PT inhibited the growth of cells and colony formation in a concentration-dependent manner and induced apoptosis as determined by the annexin V/7-aminoactinomycin D double staining assay. PT-induced apoptosis was accompanied by cell cycle arrest in the G2/M phase and an increase in the generation of reactive oxygen species (ROS). The effects of PT on the induction of ROS and apoptosis were prevented by pretreatment with N-acetyl-L-cysteine (NAC), indicating that an increase in ROS generation mediates the apoptosis of HCT116 cells induced by PT. Furthermore, Western blot analysis showed that PT upregulated the level of phospho (p)-p38 mitogen-activated protein kinase (MAPK). The treatment of SB203580, a p38 inhibitor, strongly prevented the apoptosis induced by PT, suggesting that PT-induced apoptosis involved the p38 MAPK signaling pathway. In addition, PT induced the loss of mitochondrial membrane potential and multi-caspase activation. The results suggested that PT induced cell cycle arrest in the G2/M phase and apoptosis through the p38 MAPK signaling pathway by upregulating ROS in HCT116 cells.

Refractive status of Elementary School Children in Gyeongsan-si, Gyeongbuk

Ki-Seok Lee,Seung-On Park,Ji-Won Jung 대한시과학회 2017 대한시과학회지 Vol.19 No.4

목적: 경북 경산시 내외의 초등학생들의 나안시력 및 굴절상태를 비교, 분석하여 시력의 기초자료로 사 용하고자 한다. 방법: 경산교육지원청 주관 ‘밝고 투명한 아이(eye) 만들기’ 사업의 일환으로 2015년 9월-10월 동안 보 건교사가 있는 1개의 초등학교(도시)와 미 배치된 5개의 초등학교(농촌) 총 529명을 대상으로 자동굴절검사 기기를 이용한 굴절이상도 검사, 안경 미착용자의 나안시력과 안경착용자의 교정시력을 측정하여 지역별로 비교 분석하였다. 결과: 안경미착용자의 나안시력에서 도시 초등학생들의 시력은 평균 0.79±0.23이며, 농촌은 0.78±0.23 으로 통계적 유의성은 없었으며, 두 지역 간의 시력 분포도 큰 차이를 보이지 않았다. 학년별 비교에서는 도 시 초등학생과는 다르게 농촌 초등학생에서만 고학년이 저학년 보다 나안시력이 떨어졌지만(p<0.05), 지역 별 비교에서는 차이가 나타나지 않았다. 또한, 성별에서도 남녀 간의 의미 있는 나안시력 차이를 보이지 않 았다. 등가구면 굴절력의 비교에서는 도시 초등학생의 근시가 농촌보다 많은 근시를 갖고 있었다(p<0.05). 안경착용자의 도시와 농촌지역의 평균 교정시력은 각각 0.88±0.20와 0.82±0.21로 도시 초등학생들의 교정 상태가 좋았으며, 통계적으로 유의한 차이를 보였다(p<0.05). 0.7이하의 미교정 비율은 도시 초등학생들이 농촌 초등학생들보다 오히려 12% 높은 수치를 나타냈다. 결론: 도시와 농촌의 지역적 특성을 구분한 초등학생 시력과 굴절이상도에 대한 선행연구와는 달리, 스마 트폰 보급의 대중화로 인한 초등학생들의 근거리 작업시간 증가로 초등학생들의 시력변화 특히, 저학년의 근 시증가와 근시도의 가속화에 대한 예방과 사회적 관심을 중심으로 연구가 이루어져야 할 것으로 사료된다. Purpose : To employ the basic data on visual acuity through comparison and analysis of naked vision and refractive status in elementary school children (ESC) inside and outside Gyeongsan-si Gyeongbuk. Methods : As part of the project named ‘Making Bright and Clear Eyes’ sponsored by Gyeongsan Office of Education between September and October in 2015, we compared and analysed by regional groups data of total 529 school children on refractive errors using a auto-refractometer, and naked vision of those not wearing glasses and visual acuity of those wearing glasses in one elementary school with a school nurse teacher (urban elementary school, UES) and 5 elementary schools without a school nurse teacher (rural elementary schools, RES). Results : In naked vision of those not wearing glasses, the mean of vision was 0.79±0.23 in UES and 0.78±0.23 in the RES, which is not significant, and also the distributions of vision between two regions were shown little differences. In grade comparison while naked vision of a high grade group was lower than a low grade group (p<0.05) only in RES different from UES, there is no significant difference in comparison of two regions. Also, no significant difference in naked vision between gender was found. In comparison of spherical equivalent power, children in UES are myopic much more than those in RES (p<0.05). On visual acuity of those wearing glasses, the means of visual acuity in urban and rural regions were 0.88±0.20 and 0.82±0.21, respectively, showing that refractive correction of those in UES was better, which is a significant difference (p<0.05). In the rate of under-correction in vision of 0.7 or less, it appeared that children in RES were 12% higher than those in UES. Conclusion : Unlike preceding research on vision and refractive errors of ESC with division of a regional characteristics as two areas, under the environment in which the time for near work is by far exposed as the use of smart-phone is already popularized, it would be considered social concern on vision care and prevention, and observation of the change in visual acuity of the whole elementary school children, especially to conduct research on the increase of the number of myopes and acceleration of myopic progression in low grade school children.

9개월 영아에서 발생한 대상포진 1례

근승언,이수영,김선미,정대철,정승연,강진한,Keun, Seung On,Lee, Soo Young,Kim, Sun Mi,Jeong, Dae Chul,Chung, Seung Yun,Kang, Jin-Han 대한소아감염학회 2002 Pediatric Infection and Vaccine Vol.9 No.2

저자들은 임신 중에 수두를 앓거나 수두 환자와 접촉한 과거력이 없는 산모로부터 출산된 신생아가 생후 7일에 수두를 앓고 난 직후의 아이와 접촉한 후 생후 9개월에 우측 11번 흉곽 신경절을 따라 발생된 대상포진을 임상 및 검사로 확진하였고, acyclovir로 치유한 경험을 하였기에 문헌 고찰과 함께 보고하는 바이다. We experienced a case of herpes zoster in a 9-months aged infant as followings; The patient had no history of chickenpox or varicella vaccination. Also, her mother had no history of varicella infection and no contact history with varicella during pregnancy. The patient had only a history of exposure to chickenpox patient at 7th days after birth, but fortunately chickenpox was not developed. Sequentially, symptoms of cough with fever and tachypnea were developed on admission date(7 days had passed already after development of the initial skin lesion). On physical examination, multiple grouped painless erythematous papulovesicles with small crusts were observed on the right lower back, flank and abdomen along the T11 dermatome. Coarse breathing sound was osculated, and increased linear infiltrations on both parahilar areas were seen on chest radiography. Liver enzymes were slightly elevated. Tzanck test was negative. The initial titers of anti-VZV IgM and IgG on admission were negative, but the following titers of anti-VZV IgM and IgG were positive. The patient received treatment of acyclovir for 7 days, and healed completely without sequelae. We report this case with brief review of related literatures.

DEGREE OF NEARNESS

Seung On Lee,Eun Pyo Lee 충청수학회 2008 충청수학회지 Vol.21 No.2

This paper is a revised version of [5]. In [5], we define ’nearness between two points’ in a topological space in many ways and show that a continuous function preserves one-sided nearness. We also show that a T1-space is characterized by one-sided nearness exactly. In this paper, we introduce extremally disconnected spaces and show that the new topology generated by the set of equivalence classes as a base is extremally disconnected.

SOME STRUCTURES ON A COMPLETE LATTICE

Seung On Lee,Yong Ho Yon 충청수학회 2007 충청수학회지 Vol.20 No.3

In this paper, we de¯ne V-structure, W-structure to generalize some lattices, and study the conditions that a lattice which has V-structure or W-structure to be continuous or algebraic.

Tests of the YOnsei University Research model System - Global Spectral Model (YOURS-GSM) : Retrospective forecasts

Seung-On Hwang,Byung-Kwon Park,Young-Hwa Byun,Kyung-Hee Seol,Hoon Park,Song-You Hong 한국기상학회 2006 한국기상학회 학술대회 논문집 Vol.2006 No.-

DE MORGAN FRAMES

SEUNG ON LEE, JI HYUN OH 충북대학교 금융수학연구소 2006 금융수학연구소학술지 Vol.2 No.-

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ON THE C-NETS

Seung On Lee,Young Jin Pi,Ji Hyun Oh 충청수학회 2010 충청수학회지 Vol.23 No.1

In this paper, we define the concept of a c-net and study the convergence of c-nets. Also we show that a c-net in a topological space X has a convergent sub-c-net if and only if X is a Lindel¨of space, if every G set is open in X.

ALGEBRAIC MEET CONTINUOUS LATTICE

Seung On Lee,Yong Ho Yon 충청수학회 2007 충청수학회지 Vol.20 No.4

This paper is sequel to [3]. In this paper, we discuss some properties of an algebraic meet-continuous lattice and study a complete lattice which can be embedded into an algebraic meet-continuous lattice.