• 제목/요약/키워드: Level Shift

검색결과 897건 처리시간 0.032초

동시출현단어 분석을 이용한 토양침식 연구동향 비교 분석 (A Comparison of Current Trends in Soil Erosion Research Using Keyword Co-occurrence Analysis)

  • 임영협;김석우;남수연;전근우;김민석
    • 한국환경생태학회지
    • /
    • 제34권5호
    • /
    • pp.413-424
    • /
    • 2020
  • 최근의 환경정책과 산업은 사후관리에서 사전예방 중심으로 그 패러다임이 변화하고 있다. 이에 따라 국토의 유한자원으로서의 표토의 기능과 가치에 대한 인식 제고를 바탕으로 보전예방적으로 관리하기 위한 정책이 추진되고 있다. 이러한 배경을 바탕으로 이 연구에서는 국제·국내 전문학술지의 검색 데이터베이스(Web of science)를 기반으로 최근 10년간의 연구논문에 대하여 VOSviewer를 이용한 동시출현단어 분석을 실시하여 국내·외 토양침식 연구동향을 비교·분석하고 향후 연구방향을 제안하고자 하였다. 그 결과, 우리나라의 국토면적 대비 토양침식 관련 논문 게재건수는 세계적으로 비교적 상위에 속하고, 특히 토양침식 제어와 관련된 연구가 외국에 비해 큰 비중을 차지하고 있는 것으로 나타났다. 이러한 결과로부터 우리나라에서는 기후·지형·토지이용 여건에 따른 토양침식의 심각성을 인식하고 비교적 활발한 연구가 진행되고 있는 것으로 판단되었다. 그러나 토양침식 제어에 관한 연구영역은 외국에 비해 키워드 수가 적게 나타나 연구항목을 보다 다양화·확장할 필요가 있으며, 특히 토양침식의 프로세스와 이와 관련한 토양의 물리·화학적 특성에 대한 연구는 토양침식에 따른 문제의 근본적인 해결을 위하여 활발히 추진할 필요가 있는 분야로 나타났다.

국내 전출력 원전 적용 화재 인간신뢰도분석 절차 개발 (Development of a Fire Human Reliability Analysis Procedure for Full Power Operation of the Korean Nuclear Power Plants)

  • 최선영;강대일
    • 한국안전학회지
    • /
    • 제35권1호
    • /
    • pp.87-96
    • /
    • 2020
  • The purpose of this paper is to develop a fire HRA (Human Reliability Analysis) procedure for full power operation of domestic NPPs (Nuclear Power Plants). For the development of fire HRA procedure, the recent research results of NUREG-1921 in an effort to meet the requirements of the ASME/ANS PRA Standard were reviewed. The K-HRA method, a standard method for HRA of a domestic level 1 PSA (Probabilistic Safety Assessment) and fire related procedures in domestic NPPs were reviewed. Based on the review, a procedure for the fire HRA required for a domestic fire PSA based on the K-HRA method was developed. To this end, HRA issues such as new operator actions required in the event of a fire and complexity of fire situations were considered. Based on the four kinds of HFE (Human Failure Event) developed for a fire HRA in this research, a qualitative analysis such as feasibility evaluation was suggested. And also a quantitative analysis process which consists of screening analysis and detailed analysis was proposed. For the qualitative analysis, a screening analysis by NUREG-1921 was used. In this research, the screening criteria for the screening analysis was modified to reduce vague description and to reflect recent experimental results. For a detailed analysis, the K-HRA method and scoping analysis by NUREG-1921 were adopted. To apply K-HRA to fire HRA for quantification, efforts to modify PSFs (Performance Shaping Factors) of K-HRA to reflect fire situation and effects were made. For example, an absence of STA (Shift Technical Advisor) to command a fire brigade at a fire area is considered and the absence time should be reflected for a HEP (Human Error Probability) quantification. Based on the fire HRA procedure developed in this paper, a case study for HEP quantification such as a screening analysis and detailed analysis with the modified K-HRA was performed. It is expected that the HRA procedure suggested in this paper will be utilized for fire PSA for domestic NPPs as it is the first attempt to establish an HRA process considering fire effects.

The role of dry land forests for climate change adaptation: the case of Liben Woreda, Southern Oromia, Ethiopia

  • Amanuel, Wondimagegn;Tesfaye, Musse;Worku, Adefires;Seyoum, Gezahegne;Mekonnen, Zenebe
    • Journal of Ecology and Environment
    • /
    • 제43권2호
    • /
    • pp.85-97
    • /
    • 2019
  • Background: Despite the increasing role of dry forests in climate change adaptation and mitigation, these versatile resources has got less attention in the national and regional planning, their potential to enhance the local and national economy has been overlooked, and their contribution to sustainable environmental management has not been recognized. Hence, the objective of this study was to assess the socioeconomic contribution of dry forests and forest products to climate change adaptation in the Liben Woreda, Southern Oromia region of Ethiopia. Methods: For this study, an integrated qualitative and quantitative approach was used. A total of 74 households from villages in the Bulbul, Boba, and Melka-Guba kebeles were randomly selected for the household survey. Results: Results showed that 75% of the respondents in the area indicated that climate change has become their major sources of vulnerability, where drought has been manifested in the form of crops failure and massive death of livestock particularly cattle species. The main income strategies of the study households include livestock, crop, forests such as gum and resins, firewood and charcoal and non-farm activities such as in the form of petty trade, wage and aid. The average total household income was ETB 11,209.7. Out of this, dry forest income constituted 15% of the total income. In addition to using dry forests as rangeland for livestock, the communities collect wood for construction, fodder, traditional medicine, and forest food both for subsistence and for sale. On the other hand, dry forest products could be considered as less vulnerable, rather resilient livelihood strategies to climate- and environment-related risks compared to livestock and crop production such as in the face of drought periods. More than 48.6% of the households argued that the income generated from dry forests increased substantially due to increment in the level of engagement of family members in forest based income activities. On the other hand, 35.8% of the households responded that livestock production, particularly camels and goats, have been making the livelihood strategies of the respondents more resilient indicating the shift made from grazers browsers to livestock. In general trends show that, the trends of livelihood dependency on dry forest were highly increasing indicating the importance of dry forest income in responsse to frequent droughts. Conclusions: Dry forest income has been becoming crucial livelihood staretgy in response to frequent droughts in the study area and hence, it is important to improve the management of dry forests for livelihood enhancement, while also securing their long-term ecological functions.

대기중 $CO_2$농도 증가에 따른 기후변화가 농업기후자원, 식생의 순 1차 생산력 및 벼 수량에 미치는 영향 (Impact of Climate Change Induced by the Increasing Atmospheric $CO_2$Concentration on Agroclimatic Resources, Net Primary Productivity and Rice Yield Potential in Korea)

  • 이변우;신진철;봉종헌
    • 한국작물학회지
    • /
    • 제36권2호
    • /
    • pp.112-126
    • /
    • 1991
  • The atmospheric carbon dioxide concentration is ever-increasing and expected to reach about 600 ppmv some time during next century. Such an increase of $CO_2$ may cause a warming of the earth's surface of 1.5 to 4.5$^{\circ}C$, resulting in great changes in natural and agricultural ecosystems. The climatic scenario under doubled $CO_2$ projected by general circulation model of Goddard Institute for Space Studies(GISS) was adopted to evaluate the potential impact of climate change on agroclimatic resources, net primary productivity and rice productivity in Korea. The annual mean temperature was expected to rise by 3.5 to 4.$0^{\circ}C$ and the annual precipitation to vary by -5 to 20% as compared to current normal climate (1951 to 1980), resulting in the increase of possible duration of crop growth(days above 15$^{\circ}C$ in daily mean temperature) by 30 to 50 days and of effective accumulated temperature(EAT=∑Ti, Ti$\geq$1$0^{\circ}C$) by 1200 to 150$0^{\circ}C$. day which roughly corresponds to the shift of its isopleth northward by 300 to 400 km and by 600 to 700 m in altitude. The hydrological condition evaluated by radiative dryness index (RDI =Rn/ $\ell$P) is presumed to change slightly. The net primary productivity under the 2$\times$$CO_2$ climate was estimated to decrease by 3 to 4% when calculated without considering the photosynthesis stimulation due to $CO_2$ enrichment. Empirical crop-weather model was constructed for national rice yield prediction. The rice yields predicted by this model under 2 $\times$ $CO_2$ climatic scenario at the technological level of 1987 were lower by 34-43% than those under current normal climate. The parameters of MACROS, a dynamic simulation model from IRRI, were modified to simulate the growth and development of Korean rice cultivars under current and doubled $CO_2$ climatic condition. When simulated starting seedling emergence of May 10, the rice yield of Hwaseongbyeo(medium maturity) under 2 $\times$ $CO_2$ climate in Suwon showed 37% reduction compared to that under current normal climate. The yield reduction was ascribable mainly to the shortening of vegetative and ripening period due to accelerated development by higher temperature. Any simulated yields when shifted emergence date from April 10 to July 10 with Hwaseongbyeo (medium maturity) and Palgeum (late maturity) under 2 $\times$ $CO_2$ climate did not exceed the yield of Hwaseongbyeo simulated at seedling emergence on May 10 under current climate. The imaginary variety, having the same characteristics as those of Hwaseongbyeo except growth duration of 100 days from seedling emergence to heading, showed 4% increase in yield when simulated at seedling emergence on May 25 producing the highest yield. The simulation revealed that grain yields of rice increase to a greater extent under 2$\times$ $CO_2$-doubled condition than under current atmospheric $CO_2$ concentration as the plant type becomes more erect.

  • PDF

GloSea5의 과거기후 모의자료에서 나타난 El Niño와 관련된 동아시아 강수 및 기온 예측성능 (Prediction Skill of East Asian Precipitation and Temperature Associated with El Niño in GloSea5 Hindcast Data)

  • 임소민;현유경;강현석;예상욱
    • 대기
    • /
    • 제28권1호
    • /
    • pp.37-51
    • /
    • 2018
  • In this study, we investigate the performance of Global Seasonal Forecasting System version 5 (GloSea5) in Korea Meteorological Administration on the relationship between El $Ni{\tilde{n}}o$ and East Asian climate for the period of 1991~2010. It is found that the GloSea5 has a great prediction skill of El $Ni{\tilde{n}}o$ whose anomaly correlation coefficients of $Ni{\tilde{n}}o$ indices are over 0.96 during winter. The eastern Pacific (EP) El $Ni{\tilde{n}}o$ and the central Pacific (CP) El $Ni{\tilde{n}}o$ are considered and we analyze for EP El $Ni{\tilde{n}}o$, which is well simulated in GloSea5. The analysis period is divided into the developing phase of El $Ni{\tilde{n}}o$ summer (JJA(0)), mature phase of El $Ni{\tilde{n}}o$ winter (D(0)JF(1)), and decaying phase of El $Ni{\tilde{n}}o$ summer (JJA(1)). The GloSea5 simulates the relationship between precipitation and temperature in East Asia and the prediction skill for the East Asian precipitation and temperature varies depending on the El $Ni{\tilde{n}}o$ phase. While the precipitation and temperature are simulated well over the equatorial western Pacific region, there are biases in mid-latitude region during the JJA(0) and JJA(1). Because the low level pressure, wind, and vertical stream function are simulated weakly toward mid-latitude region, though they are similar with observation in low-latitude region. During the D(0)JF(1), the precipitation and temperature patterns analogize with observation in most regions, but there is temperature bias in inland over East Asia. The reason is that the GloSea5 poorly predicts the weakening of Siberian high, even though the shift of Aleutian low is predicted. Overall, the predictability of precipitation and temperature related to El $Ni{\tilde{n}}o$ in the GloSea5 is considered to be better in D(0)JF(1) than JJA(0) and JJA(1) and better in ocean than in inland region.

비스테로이드성 항염증제와 효소 억제제에 의한 사람 중성구 Elastase의 활성도 억제 및 분자약리학적 기전 (Inhibition of Human Neutrophil Elastase by NSAIDs and Inhibitors, and Molecular Pharmacological Mechanism of the Inhibition)

  • 강구일;김우미;홍인식;이무상
    • 대한약리학회지
    • /
    • 제32권3호
    • /
    • pp.425-431
    • /
    • 1996
  • 염증 질환의 원인이 되는 사람 중성구 elastases는 혈액에 존재하는 ${\alpha}_1-PI$${\alpha}_2-macroglobulin$과 같은 단백질 분해효소 억제제에 의하여 조절되어진다. 그러나 특수한 병리적 상황에서 과다하게 분비되는 효소나 또는 단백질 분해효소 억제제의 비정상적 작용으로 말미암아 다양한 염증질환이 유발된다. 비스테로이드성 항염증제는 염증 질환을 치료하기 위하여 이미 임상에 적용 하고 있으며, prostaglandin 합성하는 효소인 cyclooxygenases의 활성도를 억제하는 것이 그 작용 기전으로 잘 알려져 왔다. 사람 중성구 elastase의 활성도는 naproxen, phenylbutazone, oxyphenbutazone 등에 의하여 억제되었으나, ibuprofen, ketoprofen, aspirin, salicylic acid, tolmetin 등에 의하여서는 억제되지 않았다. 또한 사람 중성구 elastase의 활성도는 EDTA, EGTA, tetracycline 등에 의하여서도 억제되었다. EDTA에 의하여 2가 이온 $Ca^{++}$$Zn^{++}$등을 elastase 분자로부터 일부 제거함으로 효소 활성도가 억제되었고 Raman spectra의 변화도 강하게 일어났으며, 금속이온 $Zn^{++}$를 새로 충진함으로 그 활성도는 원래대로 회복되고 Raman spectrum도 원래 상태와 유사한 상태로 회복되었다. 이런 현상은 chelator나 chelator-like agents가 효소분자안에 존재하는 $Zn^{++}$ 이온을 제거하거나 chelation함으로 활성 부위나 그 인접 부위의 4차원 구조의 변화를 일으켰음에 기인하며 특히 -C=O나 -COOH기의 관여에 의한 것으로 생각된다.

  • PDF

Regulation of Vacuolar $H^+-ATPase$ c Gene Expression by Oxidative Stress

  • Kwak, Whan-Jong;Kim, Seong-Mook;Kim, Min-Sung;Kang, Jung-Hoon;Kim, Dong-Jin;Kim, Ho-Shik;Kown, Oh-Joo;Kim, In-Kyung;Jeong, Seong-Whan
    • The Korean Journal of Physiology and Pharmacology
    • /
    • 제9권5호
    • /
    • pp.275-282
    • /
    • 2005
  • By using differential display, we identified one of the genes encoding the multi-subunit complex protein V-ATPase, c subunit gene (ATP6L), and showed alterations of the gene expression by oxidative stresses. Expression of the ATP6L gene in Neuro-2A cells was increased by the treatment with $H_2O_2$ and incubation in hypoxic chamber, implying that the expression of the ATP6L gene is regulated by oxidative stresses. To examine mechanisms involved in the regulation of the gene expression by oxidative stresses, the transcriptional activity of the rat ATP6L promoter was studied. Transcription initiation site was determined by primer extension analysis and DNA sequencing, and promoter of the rat ATP6L and its deletion clones were constructed in reporter assay vector. Significant changes of the promoter activities in Neuro-2A cells were observed in two regions within the proximal 1 kbp promoter, and one containing a suppressor was in -195 to -220, which contains GC box that is activated by binding of Sp1 protein. The suppression of promoter activity was lost in mutants of the GC box. We confirmed by electrophoretic mobility shift and supershift assays that Sp1 protein specifically binds to the GC box. The promoter activity was not changed by the $H_2O_2$ treatment and incubation in hypoxic chamber, however, $H_2O_2$ increased the stability of ATP6L mRNA. These data suggest that the expression of the ATP6L gene by oxidative stresses is regulated at posttranscriptional level, whereas the GC box is important in basal activities of the promoter.

일부 소방공무원의 직무스트레스와 소진(Burnout)과의 관련성 (Relationship Between Job Stress and Burnout of Fire Service Officers)

  • 배진성;윤석한
    • 한국산학기술학회논문지
    • /
    • 제21권5호
    • /
    • pp.433-442
    • /
    • 2020
  • 본 연구는 소방공무원들의 직무스트레스와 소진 정도와의 관련성을 규명하고자 실시하였다. 연구대상은 D광역시 5개구의 5개 소방서에서 근무하고 있는 소방공무원 582명으로 하였으며, 조사는 2019년 7월 1일부터 9월 30일까지의 기간 동안에 구조화된 무기명 자기기입식 설문지를 이용한 설문조사에 의하였다. 연구결과, 조사대상자의 소진 정도는 직무스트레스 총점이 낮은 군보다 높은 군일수록 유의하게 높았으며, 소진과 직무스트레스와의 상관관계에서도 유의한 양의 상관관계를 보여 직무스트레스가 높을수록 소진정도가 심해지는 것으로 나타났다. 소진에 대한 직무스트레스의 관련성을 알아보기 위하여 로지스틱회귀분석을 실시한 결과, 「고위험 소진 군」이 나타날 위험비는 직무스트레스가 낮은 군에 비해 매우 높은 군에서 유의하게 높았다. 소진에 영향을 미치는 요인을 알아보기 위해 다중회귀분석을 실시한 결과, 소진에 영향을 미치는 요인으로는 성, 연령, 근무경력, 교대근무여부, 업무의 신체적 부담정도, 업무에 대한 만족도, 직업전환의사 및 직무스트레스가 유의한 변수로 선정되었다. 이상과 같은 연구결과는 소방공무원들의 직무스트레스는 소진 정도와 밀접한 관련성이 있음을 시사하고 있어 직무스트레스 요인을 적절하게 통제할 수 있는 프로그램의 개발 및 운영이 필요하다고 본다.

Expression characterization and transcription regulation analysis of porcine Yip1 domain family member 3 gene

  • Ni, Dongjiao;Huang, Xiang;Wang, Zhibo;Deng, Lin;Zeng, Li;Zhang, Yiwei;Lu, Dongdong;Zou, Xinhua
    • Asian-Australasian Journal of Animal Sciences
    • /
    • 제33권3호
    • /
    • pp.398-407
    • /
    • 2020
  • Objective: The Yip1 domain family (YIPF) proteins were proposed to function in endoplasmic reticulum (ER) to Golgi transport and maintenance of the morphology of the Golgi, which were homologues of yeast Yip1p and Yif1p. YIPF3, the member 3 of YIPF family was a homolog of Yif1p. The aim of present study was to investigate the expression and regulation mechanism of porcine YIPF3. Methods: Quantitative realtime polymerase chain reaction (qPCR) was used to analyze porcine YIPF3 mRNA expression pattern in different tissues and pig kidney epithelial (PK15) cells stimulated by polyinosine-polycytidylic acid (poly [I:C]). Site-directed mutations combined with dual luciferase reporter assays and electrophoretic mobility shift assay (EMSA) were employed to reveal transcription regulation mechanism of porcine YIPF3. Results: Results showed that the mRNA of porcine YIPF3 (pYIPF3) was widely expressed with the highest levels in lymph and lung followed by spleen and liver, while weak in heart and skeletal muscle. Subcellular localization results indicated that it expressed in Golgi apparatus and plasma membranes. Upon stimulation with poly (I:C), the level of this gene was dramatically up-regulated in a time- and concentration-dependent manner. pYIPF3 core promoter region harbored three cis-acting elements which were bound by ETS proto-oncogene 2 (ETS2), zinc finger and BTB domain containing 4 (ZBTB4), and zinc finger and BTB domain containing 14 (ZBTB14), respectively. In which, ETS2 and ZBTB4 both promoted pYIPF3 transcription activity while ZBTB14 inhibited it, and these three transcription factors all played important regulation roles in tumorigenesis and apoptosis. Conclusion: The pYIPF3 mRNA expression was regulated by ETS2, ZBTB4, and ZBTB14, and its higher expression in immune organs might contribute to enhancing ER to Golgi transport of proteins, thus adapting to the immune response.

제조업 남성 근로자의 직무스트레스와 피로와의 관련성 (Relationship between Job Stress and Fatigue Symptoms among Manufacturing Male Workers)

  • 이후연;백종태;조영채
    • 한국산학기술학회논문지
    • /
    • 제17권7호
    • /
    • pp.543-554
    • /
    • 2016
  • 본 연구의 목적은 제조업 남성 근로자들의 직무스트레스 요인과 피로수준과의 관련성을 조사하기 위함이다. 연구대상자는 50인 미만의 소규모 제조업 사업장에서 근무하고 있는 남성 근로자를 553명으로 하였다. 자료 수집은 2015년 4월에 한국인 직무스트레스 측정도구와 한국판 다차원피로척도를 사용한 구조화된 설문지를 이용하여 실시하였으며, 수집된 자료는 SPSS ver 21.0 프로그램을 이용하여 분석하였다. 연구결과, 조사대상자의 피로증상은 직무스트레스가 정상인 군보다 고위험 스트레스군에서 유의하게 높았다. 또한 조사대상자의 피로증상은 직무스트레스와 유의한 양의 상관관계를 보였으며, 직무스트레스가 정상인 군에 비해 고위험 스트레스 군에서 고위험 피로군에 속할 위험비가 유의하게 증가하였다. 또한 피로수준에 영향을 미치는 요인으로는 연령, 결혼상태, 교육수준 및 주관적 건강상태. 수면시간, 커피음용 횟수, 외래진료경험 유무, 직장생활 만족도 및 직무스트레스가 유의한 변수로 선정되었으며 이들의 설명력은 27.7%이었다. 위와 같은 연구결과는 소규모 제조업 남성 근로자들의 피로수준은 인구사회학적 특성, 건강관련행위 특성 및 직업관련 특성뿐만 아니라 직무스트레스 요인과도 유의한 관련성이 있음을 시사하고 있다.