• Title/Summary/Keyword: long-term change

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Regionality and Variability of Net Primary Productivity and Rice Yield in Korea (우리 나라의 순1차생산력 및 벼 수량의 지역성과 변이성)

  • JUNG YEONG-SANG;BANG JUNG-HO;HAYASHI YOSEI
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.1 no.1
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    • pp.1-11
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    • 1999
  • Rice yield and primary productivity (NPP) are dependent upon the variability of climate and soil. The variability and regionality of the rice yield and net primary productivity were evaluated with the meteorological data collected from Korea Meteorology Administration and the actual rice yield data from the Ministration of Agriculture and Forestry, Korea. The estimated NPP using the three models, dependent upon temperature(NPP-T), precipitation(NPP-P) and net radiation(NPP-R), ranged from 10.87 to 17.52 Mg ha$^{-1}$ with average of 14.69 Mg ha$^{-1}$ in the South Korea and was ranged 6.47 to 15.58 Mg ha$^{-1}$ with average of 12.59 Mg ha$^{-1}$ in the North Korea. The primary limiting factor of NPP in Korea was net radiation, and the secondary limiting factor was temperature. Spectral analysis on the long term change in air temperature in July and August showed periodicity. The short periodicity was 3 to 7 years and the long periodicity was 15 to 43 years. The coefficient of variances, CV, of the rice yield from 1989 to 1998 ranged 3.23 percents to 12.37 percents which were lower than past decades. The CV's in Kangwon and Kyeongbuk were high while that in Chonbuk was the lowest. The prediction model based on th e yield index and yield response to temperature obtain ed from the field crop situation showed reasonable results and thus the spatial distributions of rice yield and predicted yield could be expressed in the maps. The predicted yields was well fitted with the actual yield except Kyungbuk. For better prediction, modification should be made considering radiation factor in further development.

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Estimation of sediment deposition rate in collapsed reservoirs(wetlands) using empirical formulas and multiple regression models (경험공식 및 다중회귀모형을 이용한 붕괴 저수지(습지) 비퇴사량 추정)

  • Kim, Donghyun;Lee, Haneul;Bae, Younghye;Joo, Hongjun;Kim, Deokhwan;Kim, Hung Soo
    • Journal of Wetlands Research
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    • v.23 no.4
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    • pp.287-295
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    • 2021
  • As facilities such as dam reservoir wetlands and agricultural irrigation reservoir wetlands are built, sedimentation occurs over time through erosion, sedimentation transport, and sediment deposition. Sedimentation issues are very important for the maintenance of reservoir wetlands because long-term sedimentation of sediments affects flood and drought control functions. However, research on resignation has been estimated mainly by empirical formulas due to the lack of available data. The purpose of this study was to calculate and compare the sediment deposition rate by developing a multiple regression model along with actual data and empirical formulas. In addition, it was attempted to identify potential causes of collapse by applying it to 64 reservoir wetlands that suffered flood damage due to the long rainy season in 2020 due to reservoir wetland sedimentation and aging. For the target reservoir, 10 locations including the GaGog reservoir located in Miryang city, Gyeongsangnam province in South Korea, where there is actual survey information, were selected. A multiple regression model was developed in consideration of physical and climatic characteristics, and a total of four empirical formulas and sediment deposition rate were calculated. Using this, the error of the sediment deposition rate was compared. As a result of calculating the sediment deposition rate using the multiple regression model, the error was the lowest from 0.21(m3km2/yr) to 2.13(m3km2/yr). Therefore, based on the sediment deposition rate estimated by the multi-regression model, the change in the available capacity of reservoir wetlands was analyzed, and the effective storage capacity was found to have decreased from 0.21(%) to 16.56(%). In addition, the sediment deposition rate of the reservoir where the overflow damage occurred was relatively higher than that of the reservoir where the piping damage occurred. In other words, accumulating sediment deposition rate at the bottom of the reservoir would result in a lack of acceptable effective water capacity and reduced reservoir flood and drought control capabilities, resulting in reservoir collapse damage.

Distribution Characteristics, Population Structure and Dynamics of the Endangered Plant, Viola websteri Hemsl. (멸종위기야생식물인 왕제비꽃(Viola websteri Hemsl.)의 분포특성과 개체군 구조 및 동태)

  • Chae, Hyun-Hee;Kim, Young-Chul;Kwak, Myoung-Hai;Nam, Gi-Heum
    • Korean Journal of Environment and Ecology
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    • v.35 no.1
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    • pp.48-67
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    • 2021
  • Plant species exhibit current characteristics as a result of interactions with environmental conditions. The plants of Viola sp. have selected chasmogamous flowers with vigorous vegetative propagation or development of cleistogamous flowers as an adaptation strategy. Viola websteri is distributed on the Korean peninsula and the eastern part of Jilin Province, China. The center and edge of the distribution are expected to exhibit different population-dynamics. It is necessary to investigate the cause of its current limited distribution even though V. websteri has a mixed-mating strategy. Firstly, We examined the vegetation environment of habitats and evaluated its characteristics. Growth characteristics were examined through plant phenology. We then evaluated the population structure, characteristics of chasmogamous flowers, and productivity of cleistogamous flowers. Moreover, we compared population sizes between 2014 and 2018. Most habitats were located in deciduous broadleaf mixed forests adjacent to valleys. V. websteri produced chasmogamous flowers with self-incompatibility in April-May and cleistogamous flowers in June-September. The cleistogamous flower production is a strategy ensuring seed production under uncertain environmental fluctuations; these were approximately twice as numerous as chasmogamous flowers. The population structure was distinguished into stable and very unstable regions. There were sites where the population experienced a sharp decline in the 2018 compared to that of 2014. This large decline was found in the edge populations. The habitats had different microsites depending on the natural disturbances of drought and the matrix constituting the habitat, thus supporting various plants. Ensuring the production of seeds through cleistogamous flowers, it was determined that rapid seedling re-establishment and population replenishment were possible when the natural disturbance factor was removed. Environmental factors did not equally affect all populations or individuals. Therefore, it was expected that it would be able to persisted in a long time, despite the rapid decrease in the number of individuals in the population regionally. Local extinction and re-establishment are likely to repeat according to environmental change. We propose the additional population investigation based on this works are required. We also suggest a need to assess the long-term population dynamics and the genetic characteristics of chasmogamous flowers and cleistogamous flowers to establish and implement effective conservation strategies.

Analysis of the Relationship between the Flow Characteristics of the Tsushima Warm Current and Pacific Decadal Oscillation (대마난류의 유동 특성과 PDO의 관계 분석)

  • Seo, Ho-San;Chung, Yong-Hyun;Kim, Dong-Sun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.6
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    • pp.882-889
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    • 2022
  • In this study, to understand the factors influencing the flow change the Tsushima Warm Current (TWC), the correlation between the volume transport the TWC, El Niño Southern Oscillation (ENSO), and Pacific Decadal Oscillation (PDO) was analyzed. A calculation of the monthly volume transport of TWC for 25 years (1993-2018) revealed that the seasonal fluctuation cycle was the largest in summer and smallest in winter. Power spectrum analysis to determine the periodicity of the TWC volume transport, Oceanic Niño Undex (ONI), and PDO indicated that the TWC volume transport peaked at a one year cycle, but ONI and PDO showed no clear cycle. Further, to understand the correlation between the TWC transport volume and ONI and PDO, the coherence estimation method was used for analysis. The coherence of ONI and PDO had a high mutual contribution in long-period fluctuations of three years or more but had low mutual contribution in short-period fluctuations within one year. However, the coherence value between the two factors of the TWC volume transport and PDO was 0.7 in the 0.8-1.2 year cycle, which had a high mutual contribution. Meanwhile, the TWC volume transport and PDO have an inverse correlation between period I (1993-2002) and period III (2010-2018). When the TWC maximum transport volume (2.2 Sv or more) was high, the PDO index showed a negative value below -1.0, and the PDO index showed a positive value when the TWC maximum transport volume was (below 2.2 Sv). Therefore, using long-term PDO index data, changes in the TWC transport volume and water temperature in the East Sea coastal area could be predicted.

A Servicism Model of the New Legal System (서비스주의 법제도 구조와 운용 연구)

  • Hyunsoo Kim
    • Journal of Service Research and Studies
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    • v.11 no.4
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    • pp.1-20
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    • 2021
  • This study was conducted to derive a model of the legal system that is the basis for realizing the service economy, political administration, and social education system. Based on the experience of mankind's legal system operation in the historical era for the past 5,000 years, a legal system model that will make the future human society sustainable has been established. The problems of the current legal system were analyzed at the fundamental level. The root cause of injustice and unfairness was analyzed and a new legal system was designed. Through the legal systems of various national societies that have been attempted in the history of mankind, the structure of the legal system that is desirable for the modern society was designed. Human society, which has experienced how much good legal system has been and is being abused by human irrationality and nonsense, needs to make an effort to change the legal system paradigm itself by learning lessons from failure. This study derives the basis for a legal system that can realize justice and a fair society in the long term. It proposed a model for improving the legal system that allows human society to be happy for a long time. To this end, the fundamental role of the legal system was analyzed at the ideological level and the problems of the current legal system were presented. In addition, the problem of fundamental assumptions about human nature was analyzed and improved assumptions were presented. The structural system of the current legal system was analyzed and a new structure was proposed. In addition, a plan for the operation of a new legal system based on a new structure was suggested. The new legal system was named servicism system. This is because it is a model centered on thorough checks and balances between all opponents, not a simple linear one-dimensional legal system, but a multidimensional legal system, and because it is a viewpoint that clearly recognizes both human reason and desire. The new system is a model that reflects the confrontation between the rule of law and the non-law rule and the confrontation between the power people and the general public. A follow-up study is needed on a concrete plan for transitioning from the current legal system to a new legal system.

Incidence of Chronic Pathologic Nephrotoxicity of Cyclosporine A in Pediatric Nephrotic Syndrome (소아 신증후군에서 Cyclosporine A에 의한 만성 조직학적 신독성의 발현빈도에 대한 연구)

  • Kim Ji-Hong;Jeong Hyun-Ju;Choi In-Jun;Kim Pyung-Kil
    • Childhood Kidney Diseases
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    • v.3 no.2
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    • pp.130-144
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    • 1999
  • Purpose : Long-term use of Cyclosporine(CsA) reduce renal blood flow by afferent arteriolar vasoconstriction and lead to chronic pathologic changes of CsA nephrotoxicity - 1) interstitial nephritis(IN); tubular atrophy (TA) and/or interstitial fibrosis(IF),2) arteriolopathy(AP). The Object of this study is to estimate the incidence of chronic pathologic CsA nephrotoxicity by duration of treatment and type of renal disease, relationship between histologic and clinical nephrotoxicity, and optimal duration of CsA therapy. Methods : 102 children with steroid resistant or dependent nephrotic syndrome confirmed by renal biopsy and treated with CsA from 1986 to 1997 were enrolled in this study(58 MCNS, 10 FSGS, 10 MGN, 15 $Henoch-Sch\"{o}nlein$ purpura nephritis with nephrotic syndrome (HSPN) and 9 IgA nephropathy with nephrotic syndrome(IgAN)). CsA was administered for 1yr, 1.5yr, 2yr in 24, 12, 22 MCNS patients and 2, 2, 6 FSGS patients respectively, 1yr, 2yr in MGN and 1yr in HSPN and IgAN. Sequential biopsies were done in all 102 patients after CsA treatment for evaluation of pathologic nephrotoxicity. Results : Complete remission rate was 92.2% (100% in MCNS and MGN, 80% in FSGS, 86.6% in HSPN and 55.5% in IgAN). Incidence of relapse during 6months after CsA treatment was significantly decreased compaed with relapsing spisodes during 6months before CsA treatment in MCNS(P<0.0001) and FSGS(P<0.0001). According to pathologic changes, 71 patients(69.6%) showed no pathological change, 24 patients(23.5%) showed IN and 7 patients(6.8%) showed AP. IN was 16.6%, 33.3%, 27.2% in 1, 1.5, 2 year of CsA treatment group in MCNS. AP was 0%, 16.6%, 9% in 1, 1.5, 2 year of CsA treatment group in MCNS. 14 out of 58 MCNS(24.1%) showed IN and 4 out of 58 MCNS(6.8%) showed AP. Incidence of pathologic change was significantly lower in CsA therapy of <1yr than >1yr(P=0.03). There were no significant difference of incidence of pathologic change in original renal disease, age and sex. Conclusion : Duration of CsA treatment was significant risk factor for nephrotoxicity and optimal duration seemed to be 1 year. Pathologic change due to nephrotoxicity did not correlate with deterioration of renal function and only detectable by renal biopsy.

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The Serial Change of Cerebral Hemodynamics by Vascular Territory after Extracranial-Intracranial Bypass Surgery in Patients with Atherosclerosis of Cerebral Arteries (죽상 동맥 경화성 뇌혈관 폐색 환자에서의 두개외강-내강 우회로술 후의 혈관 영역별 연속 혈류역학 변화)

  • Hong, Il-Ki;Kim, Jae-Seung;Ahn, Jae-Sung;Kwon, Sun-Uck;Im, Ki-Chun;Lee, Jai-Hyuen;Moon, Dae-Hyuk
    • Nuclear Medicine and Molecular Imaging
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    • v.42 no.1
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    • pp.8-16
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    • 2008
  • Purpose: To assess the effect of extracranial-intracranial (EC-IC) bypass surgery on hemodynamic improvement, we evaluated serial regional cerebral hemodynamic change of the middle cerebral artery (MCA) in symptomatic patients with atherosclerotic occlusion of the internal carotid artery (ICA) or MCA using $^{99m}Tc$-ECD acetazolamide stress brain perfusion SPECT (Acetazolamide SPECT). Materials and Methods: The patients who had suffered a recent stroke with atherosclerotic ICA or MCA occlusion underwent EC-IC bypass surgery and Acetazolamide SPECT at 1 week before and three to six months after surgery. For image analysis, attenuation corrected images were spatially normalized to SPECT templates with SPM2. Anatomical automated labeling was applied to calculate mean counts of each Volume-Of-Interest (VOI). Seven VOIs of bilateral frontal, parietal, temporal regions of the MCA territory and the ipsilateral cerebellum were defined. Using mean counts of 7 VOIs, cerebral perfusion index and perfusion reserve index were calculated. Results: Seventeen patients (M:F =12:5, mean age $53{\pm}2yr$) were finally included in the analysis. The cerebral blood flow of the parietal region increased at 1 week (p = 0.003) and decreased to the preoperative level at 3-6 months (p = 0.003). The cerebrovascular reserve of the frontal and parietal regions increased significantly at 1 week after surgery (p<0.01) and improved further at 3-6 months. Conclusion: Cerebrovascular reserve of the MCA territory was significantly improved at early postoperative period after EC-IC bypass and kept improved state during long-term follow-up, although cerebral blood flow did not significantly improved. Therefore, cerebrovascular reserve may be a good indicator of postoperative hemodynamic improvement resulted from bypass effect.

The Change in Beginning Science Teachers' Reflective Practice in their Teaching Performance through Collaborative Mentoring (협력적 멘토링을 통한 초임 중등과학교사의 교수실행에서 나타나는 반성적 실천의 변화)

  • Go, Munsuk;Nam, Jeonghee
    • Journal of The Korean Association For Science Education
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    • v.33 no.1
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    • pp.94-113
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    • 2013
  • The purpose of this study was to examine the change in the classes of beginning science teachers through the collaborative mentoring program that induce reflective thinking practice. Participants in this study were three mentor-teachers, two teachers in doctor's or master's course, one university professor, and three mentee-teachers who have less than four years of teaching experience. We collected data such as video recordings of the mentee-teachers' classroom teaching and transcription, lesson plans, recording of one-on-one mentoring and transcription, mentor and mentee's journals, and RTOP classroom teaching observation reports. RTOP was used for the analysis of classroom teaching and mentee-teachers' recognition and changes in their classes were found out through journals and one-on-one mentoring interview materials. According to mentee-teachers' recognition and changes in their classes during the mentoring program, they themselves recognized their teacher-centered teaching style, misconception, and lack of content knowledge. Furthermore, there were changes in the mentee-teachers' classroom teaching through their reflective practice and improvement. As a result of this study, the interactions with mentor-teachers through collaborative mentoring program stimulated mentee-teacher's reflections on their teaching. Therefore, these reflections led to their reflective practice that showed progressive changes in their teaching behavioral activities. The extent of these changes varied according to the mentee-teachers' individual disposition toward reflection and the issue of whether mentee-teachers' reflective practice was in accordance with priorities in motivational ZDP or not. Also based on the results of this study, the teachers' reflection was not all accompanied by reflective practice even if the beginning science teachers made some partial changes in reflective practice through reflection. It means that it is hard to lead reflective practice for mentee-teachers through mentoring in a short period of time. Therefore, we consider that a systematic and long-term mentoring program is necessary for beginning science teachers.

Effects of Nutrition Education on Overweight and Obese Children in Chonbuk Area -Focus on Food Habit, Eating Behaviors, Dietary Attitude, Nutrition Knowledge and Nutrients Intake- (전북지역 과체중 및 비만아동의 영양교육 효과 -식습관, 식행동, 식생활 태도, 영양지식과 영양소 섭취 상태를 중심으로-)

  • Yu, Ok-Kyeong;Rhee, Yang-Keun;Sohn, Hee-Sook;Cha, Youn-Soo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.39 no.9
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    • pp.1286-1294
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    • 2010
  • The purpose of this study was to investigate the effects of nutrition education focus on food habit, eating behaviors, dietary attitude, nutrition knowledge, and nutrients intake. The nutrition education was provided to 103 overweight and obese children in Chonbuk area. Nutrition education lessons were conducted 40 min/lesson, 12 times in year (6 times/semester). We assessed the change in knowledge using a questionnaire on food habit, eating behaviors, dietary attitude, nutrition knowledge and nutrients intake using 24 hr recall method. After the nutrition education, dietary habits were significantly improved. Especially, the answer of 'Don't eat when feel full' were significantly improved (boys (p<0.01), girls (p<0.05)). And the answer of 'Eat sugar meal frequently (chocolate, candy)' which is a dietary attitude question was significantly improved (girls (p<0.05)). There were positively changes in the dietary attitude and nutrition knowledge, but there were no significant differences after program. The results suggest that this nutrition education must be continue for positive food habit change in the long term.

A Study on Change in Cement Mortar Characteristics under Carbonation Based on Tests for Hydration and Porosity (수화물 및 공극률 관측 실험을 통한 시멘트모르타르의 탄산화 특성 변화에 대한 연구)

  • Kwon, Seung-Jun;Song, Ha-Won;Park, Sang-Soon
    • Journal of the Korea Concrete Institute
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    • v.19 no.5
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    • pp.613-621
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    • 2007
  • Due to the increasing significance of durability, much researches on carbonation, one of the major deterioration phenomena are carried out. However, conventional researches based on fully hardened concrete are focused on prediction of carbonation depth and they sometimes cause errors. In contrast with steel members, behaviors in early-aged concrete such as porosity and hydrates (calcium hydroxide) are very important and may be changed under carbonation process. Because transportation of deteriorating factors is mainly dependent on porosity and saturation, it is desirable to consider these changes in behaviors in early-aged concrete under carbonation for reasonable analysis of durability in long term exposure or combined deterioration. As for porosity, unless the decrease in $CO_2$ diffusion due to change in porosity is considered, the results from the prediction is overestimated. The carbonation depth and characteristics of pore water are mainly determined by amount of calcium hydroxide, and bound chloride content in carbonated concrete is also affected. So Analysis based on test for hydration and porosity is recently carried out for evaluation of carbonation characteristics. In this study, changes in porosity and hydrate $(Ca(OH)_2)$ under carbonation process are performed through the tests. Mercury Intrusion Porosimetry (MIP) for changed porosity, Thermogravimetric Analysis (TGA) for amount of $(Ca(OH)_2)$ are carried out respectively and analysis technique for porosity and hydrates under carbonation is developed utilizing modeling for behavior in early-aged concrete such as multi component hydration heat model (MCHHM) and micro pore structure formation model (MPSFM). The results from developed technique is in reasonable agreement with experimental data, respectively and they are evaluated to be used for analysis of chloride behavior in carbonated concrete.