• 제목/요약/키워드: Significant Events

검색결과 1,453건 처리시간 0.026초

Physical Characteristics of Two Types of EUV Coronal Jets Observed by SDO/AIA

  • 김일훈;문용재;이진이;이경선;성숙경;김갑성
    • 천문학회보
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    • 제38권1호
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    • pp.63.2-63.2
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    • 2013
  • We have investigated the EUV coronal jets observed by Solar Dynamic Observatory (SDO) / Atmospheric Imaging Assembly (AIA). From the Heliophysics Events Knowledgebase (HEK), we consider all recorded 40 EUV jets in $171{\AA}$ from May 2010 to July 2011 and use 19 jets whose location can be clearly identified, excluding limb events because of the ambiguity of their positions. According to the positions of their roots, these coronal jets are classified into two types: bright point jet (BPJ, 9 jets) and active region boundary jet (ABJ, 10 jets). BPJs are located at the top of bright points and ABJs at the boundaries of active regions. There are significant differences in speed and size between two types. Here the speed and size of a jet are assumed to be its maximum values in the case that the jet has several ejections. The average speed and size of 9 BPJs are about 110 km/s and 69,000km, respectively. The average speed and size of 10 ABJs are about 660 km/s and 194,000 km, respectively. The speed distribution of ABJs has two peaks at about 270 km/s and 1700 km/s. It is very interesting to note that three ABJs have very high speeds larger than 1600 km/s and they are all composed of a group of recurrent jets with low and high speed at the same location. In addition, we are investigating these events in other wavelengths and compare their characteristics.

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우울증을 매개로 한 청소년의 자살구상에 관한 가족 및 학교환경의 경로분석 모델 (Path Model for the Family and School Environment Affecting Adolescent Suicidal Ideation Mediated by Depression)

  • 전영주
    • 대한가정학회지
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    • 제39권1호
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    • pp.151-167
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    • 2001
  • This study tests the path model which examines how the variables of past and present family dynamics, school adjustment, filed life events affect the adolescents'depression which in tum influencing their suicidal ideation. In the path model, the exogenous varialbes were negative parenting experience in childhood, maladjustment history of the family (e.g., alcohol, divorce), present parent-adolesecent communication, school adjustment, filed life events were used, whereas the adolescent depression was used as the mediated variable. The endogenous variable was the adolescent suicidal ideation. The respondents of the survey were 635 adolescent who were 1st and 2nd grade of high school located in Seoul and Busan. Using SPSS for Windows, the path analysis was done for male and female adolescents separately, since female adolescents were found to report significantly higher degree of depression and suicidal ideation then were male adolescents. The results of the path analysis were as followings. First, for both the male and female adolescents, depression was the strongest predictor of their suicidal ideation. Also, school adjustment strongly affected the adolescents'depression as well as their suicidal ideation. Meanwhile, filed life events indirectly influenced the suicidal ideation only through the depression. Second, for the male adolescents, negative parenting experience in childhood affected both the depression and suicidal ideation, while the parent-adolescent communication directly affected the suicidal ideation. Third, for the female adolescents, maladjustment family history and negative parenting experience did not affect their depression, but the suicidal ideation. Meanwhile, parent-adolescent communication was a significant predictor of female adolescents'suicidal ideation as well as their depression. In conclusion, discussion on different path of male and female adolescents'suicidal ideation was provided.

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Potentiation of T Cell Stimulatory Activity by Chemical Fixation of a Weak Peptide-MHC Complex

  • Hwang, Inkyu;Kim, Kwangmi;Choi, Sojin;Lomunova, Maria
    • Molecules and Cells
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    • 제40권1호
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    • pp.24-36
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    • 2017
  • The stability of peptide-MHC complex (pMHC) is an important factor to shape the fate of peptide-specific T cell immune response, but how it influences on T cell activation process is poorly understood. To better understand that, we investigated various T cell activation events driven by $L^d$ MHCI loaded with graded concentrations of P2Ca and QL9 peptides, respectively, with 2C TCR Tg T cells; the binding strength of P2Ca for $L^d$ is measurably weaker than that of QL9, but either peptides in the context of $L^d$ interact with 2C TCR with a similar strength. When their concentrations required for early T cell activation events, which occur within several minutes to an hour, were concerned, $EC_{50}s$ of QL9 were about 100 folds lower than those of P2Ca, which was expected from their association constants for $L^d$. When $EC_{50}s$ for late activation events, which takes over several hours to occur, were concerned, the differences grew even larger (> 300 folds), suggesting that, due to weak binding, $L^d/P2Ca$ dissociate from each other more easily to lose its antigenicity in a short time. Accordingly, fixation of $L^d/P2Ca$ with paraformaldehyde resulted in a significant improvement in its immunogenicity. These results imply that binding strength of a peptide for a MHC is a critical factor to determine the duration of pMHC-mediated T cell activation and thus the attainment of productive T cell activation. It is also suggested that paraformaldehyde fixation should be an effective tool to ameliorate the immunogenicity of pMHC with a poor stability.

FLOODING PSA BY CONSIDERING THE OPERATING EXPERIENCE DATA OF KOREAN PWRs

  • Choi, Sun-Yeong;Yang, Joon-Eon
    • Nuclear Engineering and Technology
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    • 제39권3호
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    • pp.215-220
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    • 2007
  • The existing flooding Probabilistic Safety Analysis(PSA) was updated to reflect the Korean plant specific operating experience data into the flooding frequency to improve the PSA quality. Both the Nuclear Power Experience(NPE) database and the Korea Nuclear Pipe Failure Database(NuPIPE) databases were used in this study, and from these databases, only the Pressurized Water Reactor(PWR) data were used for the flooding frequencies of the flooding areas in the primary auxiliary building. With these databases and a Bayesian method, the flooding frequencies for the flooding areas were estimated. Subsequently, the Core Damage Frequency(CDF) for the flooding PSA of the Ulchin(UCN) unit 3 and 4 plants based on the Korean Standard Nuclear Power Plant(KSNP) internal full-power PSA model was recalculated. The evaluation results showed that sixteen flooding events are potentially significant according to the screening criterion, while there were two flooding events exceeding the screening criterion of the existing UCN 3 and 4 flooding PSA. The result was compared with two kinds of cases: (1) the flooding frequency and CDF from the method of the existing flooding PSA with the PWR and Boiled Water Reactor(BWR) data of the NPE database and the Maximum Likelihood Estimate(MLE) method and (2) the flooding frequency and CDF with the NPE database(PWR and BWR data), NuPIPE database, and a Bayesian method. From the comparison, a difference in CDF results was revealed more clearly between the CDF from this study and case (2) than between case (1) and case (2). That is, the number of flooding events exceeding the screen criterion further increased when only the PWR data were used for the primary auxiliary building than when the Korean specific data were used.

사용자 컨텍스트와 페트리넷을 이용한 모바일 상의 라이프 스토리 생성 (Life Story Generation in Mobile Environments Using User Contexts and Petri Net)

  • 이영설;조성배
    • 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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    • 제14권2호
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    • pp.236-240
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    • 2008
  • 사람들은 자신의 삶을 기록하고자 하는 욕구를 충족시키기 위하여 일기를 쓰거나 사진을 찍어 기록을 남긴다. 사람이 경험한 일을 자동적으로 이야기 형태로 만들어 기록으로 남길 수 있다면 그것을 통해서 자신의 경험을 다른 사람과 공유할 수 있고, 쉽게 자신의 과거 경험을 돌이켜 볼 수 있을 것이다. 본 논문에서는 모바일 기기를 통해서 얻을 수 있는 사용자 컨텍스트를 바탕으로 사람이 경험한 일들을 이야기 형식으로 구성하는 방법을 제안한다. 여기서는 사용자가 수행한 행위나 경험한 사건을 인과적이거나 시간적 순서로 연결해주기 위하여 Petri Net을 이용하였다. Petri Net은 동시적이고 병렬적으로 발생하는 사건이나 시스템을 모델링하는 방법으로 현실 세계의 일부를 모델링하는데 뿐만 아니라, 비선형적인 스토리 라인을 표현하는데도 적합한 방법이다. 제안한 방법의 가능성을 보이기 위하여 모바일 기기 사용자를 대상으로 수집한 사용자 컨텍스트를 바탕으로 스토리를 생성하는 사례를 보이고 유용성을 평가한다.

편두통 예방을 위한 erenumab의 유효성 및 안전성에 관한 체계적 고찰 (Systematic Review on the Efficacy and Safety of Erenumab for the Prevention of Migraine)

  • 손병우;채현우;지은희;유봉규
    • 한국임상약학회지
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    • 제29권2호
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    • pp.71-78
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    • 2019
  • Objective: This study aimed to provide efficacy and safety information on the use of erenumab for prevention of episodic and chronic migraines. Methods: The keywords "Erenumab and migraine" were used to search the PubMed database to then compile efficacy and safety data for erenumab. Data from relevant Phase 2 and Phase 3 clinical trials were analyzed, using RevMan for statistical analysis. Results: Three clinical trials (one Phase 2 and two Phase 3 studies) were retrieved. All three trials used the same primary endpoint (change from baseline in monthly migraine days (CBMD)) to evaluate efficacy and safety of erenumab use for prevention of episodic and chronic migraines. Subcutaneous doses of erenumab (70 or 140 mg) were administered monthly in each trial, for 3 months (Studies 2, and 3) or 6 months (Study 1). The mean differences in CBMD in the 70 mg and 140 mg erenumab arms were -1.36 and -1.98, respectively, compared to that in the placebo arm. Some adverse events, such as nasopharyngitis and upper respiratory tract infection, were reported, but no differences in safety between erenumab and placebo were found to be significant. Conclusions: Erenumab showed superior efficacy in prevention of migraines compared to placebo. However, additional information regarding the long-term safety of erenumab should be collected. Therefore, post-marketing surveillance for adverse events is needed.

Dynamic quantitative risk assessment of accidents induced by leakage on offshore platforms using DEMATEL-BN

  • Meng, Xiangkun;Chen, Guoming;Zhu, Gaogeng;Zhu, Yuan
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제11권1호
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    • pp.22-32
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    • 2019
  • On offshore platforms, oil and gas leaks are apt to be the initial events of major accidents that may result in significant loss of life and property damage. To prevent accidents induced by leakage, it is vital to perform a case-specific and accurate risk assessment. This paper presents an integrated method of Ddynamic Qquantitative Rrisk Aassessment (DQRA)-using the Decision Making Trial and Evaluation Laboratory (DEMATEL)-Bayesian Network (BN)-for evaluation of the system vulnerabilities and prediction of the occurrence probabilities of accidents induced by leakage. In the method, three-level indicators are established to identify factors, events, and subsystems that may lead to leakage, fire, and explosion. The critical indicators that directly influence the evolution of risk are identified using DEMATEL. Then, a sequential model is developed to describe the escalation of initial events using an Event Tree (ET), which is converted into a BN to calculate the posterior probabilities of indicators. Using the newly introduced accident precursor data, the failure probabilities of safety barriers and basic factors, and the occurrence probabilities of different consequences can be updated using the BN. The proposed method overcomes the limitations of traditional methods that cannot effectively utilize the operational data of platforms. This work shows trends of accident risks over time and provides useful information for risk control of floating marine platforms.

Installation and operation of automatic nonpoint pollutant source measurement system for cost-effective monitoring

  • Jeon, Jechan;Choi, Hyeseon;Shin, Dongseok;Kim, Lee-hyung
    • Membrane and Water Treatment
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    • 제10권1호
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    • pp.99-104
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    • 2019
  • In Korea, nonpoint pollutants have a significant effect on rivers' water quality, and they are discharged in very different ways depending on rainfall events. Therefore, preparing an optimal countermeasure against nonpoint pollutants requires much monitoring. The present study was conducted to help prepare a method for installing an automatic nonpoint pollutant measurement system for the cost-effective monitoring of the effect of nonpoint pollutants on rivers. In the present study, monitoring was performed at six sites of a river passing through an urban area with a basin area of $454.3km^2$. The results showed that monitoring could be performed for a relatively long time interval in the upstream and downstream regions, which are mainly comprised of forests, regardless of the rainfall amount. On the contrary, in the urban region, the monitoring had to be performed at a relatively short time interval each time when the rainfall intensity changed. This was because the flow rate was significantly dependent on the rainfall's intensity. The appropriate sites for installing an automatic measurement system were found to be a site before entering the urban region, a site after passing through the urban region, and the end of a river where the effects of nonpoint pollutant sources can be well-decided. The analysis also showed that the monitoring time should be longer for the rainfall events of a higher rainfall class and for the sites closer to the river end. This is because the rainfall runoff has a longer effect on the river. However, the effect of nonpoint pollutant sources was not significantly different between the upstream and the downstream in the cases of rainfall events over 100 mm.

노년기 자기 통제감에 영향을 주는 요인 (Determinants of Sense of Control in Later Life)

  • 장유리;이정남;윤현숙;김수영
    • 한국노년학
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    • 제28권4호
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    • pp.1055-1068
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    • 2008
  • 자기 통제감은 노년기의 다양한 스트레스 상황에서 신체적 정신적 건강을 보호하고 증진시키는 역할을 한다고 밝혀져 왔다. 본 연구에서는 노년기 자기 통제감에 영향을 주는 요인을 분석하였다. 주요 영향 요인을 (1) 사회 인구학적 특성, (2) 신체 건강 상태, (3) 최근 일어난 부정적 생활사건, (4) 사회 관계적 자원으로 분류하였다. 국내 다섯 개 도시에 거주하는 60세 이상 노인 291명(평균 연령 = 69.9)을 연구 대상으로 하였고, 자기 통제감은 Pearlin과 Schooler(1978)의 Mastery Scale의 7항목으로 측정되었다. 위계적 회귀분석 결과, 경제 수준, 만성 질환, 일상생활 수행 장애, 시력, 부정적 생활사건 경험, 그리고 자녀와의 관계 만족도가 자기 통제감에 유의한 영향을 주는 요인으로 밝혀졌다. 이러한 결과를 통해, 노년기 자기 통제감 증진을 위한 개입이나 사회적 프로그램 개발의 중요성을 제시하였다.

중의학 데이터베이스 (CAJ)를 이용한 급성백혈병의 한약치료에 대한 임상 연구 동향 (Review of Clinical Studies for Herbal Medicine Treatment on Acute Leukemia - Focusing on Studies from the China Academic Journal (CAJ) -)

  • 김정은;장진우;박범찬;김기봉;천진홍
    • 대한한방소아과학회지
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    • 제35권1호
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    • pp.48-62
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    • 2021
  • Objectives The purpose of this study is to obtain knowledge from clinical studies conducted in China to examine the effectiveness of herb medicine in childhood acute leukemia. Methods We searched the randomized controlled trials (RCTs) with herbal medicine treatment on childhood acute leukemia from the 'CAJ', Chinese Academic Journal from China National Knowledge Infrastructure (CNKI). And then, demographic data, duration of illness, intervention, treatment period, outcome, adverse events, and composition of herbal medicine were analyzed for this study. Result 10 RCT studies were selected and analyzed. The control group were given western medicine therapy, the treatment group was given herbal medicine on the basis of the control group. The most commonly used herbal medicine were 淸熱解毒藥, 補氣藥, 補陰藥, 活血祛瘀藥 in 'boosting vital force and driving out evil spirit (扶正祛邪)' way to 'relieve heat (熱毒)' and 'assist the vital force (正氣)'. In the treatment group, complete remission was significantly higher than control group and the decrease in TCM syndrome scores also showed significant effects. Adverse events were significantly lower in the treatment group. Conclusions Herbal medicine treatment on childhood acute leukemia can be suggested as a new treatment for children who have less response to the conventional therapy, and can supplement the limitations of the western medicine by increasing complete remission and reducing adverse events.