• 제목/요약/키워드: Long-term changes

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Methanogenesis and Methane Oxidation in Paddy Fields under Organic Fertilization

  • Kim, Chungwoo;Walitang, Denver I.;Sa, Tongmin
    • Korean Journal of Environmental Agriculture
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    • v.40 no.4
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    • pp.295-312
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    • 2021
  • BACKGROUND: Global warming is one of the most pressing environmental issues which concomitantly complicates global climate change. Methane emission is a balance between methanogenesis and methane consumption, both of which are driven by microbial actions in different ecosystems producing methane, one of the major greenhouse gases. Paddy fields are major sources of anthropogenic methane emissions and could be compounded by organic fertilization. METHODS AND RESULTS: Literature reviews were conducted to give an overview of the global warming conditions and to present the relationship of carbon and methane to greenhouse gas emissions, and the need to understand the underlying processes of methane emission. A more extensive review was done from studies on methane emission in paddy fields under organic fertilization with greater emphasis on long term amendments. Changes in paddy soils due to organic fertilization include alterations of the physicochemical properties and changes in biological components. There are diverse phylogenetic groups of methanogens and methane oxidizing bacteria involved in methane emission. Also, multiple factors influence methanogenesis and methane oxidation in rice paddy fields under organic fertilization and they should be greatly considered when developing mitigating steps in methane emission in paddy fields especially under long term organic fertilization. CONCLUSION(S): This review showed that organic fertilization, particularly for long term management practices, influenced both physicochemical and biological components of the paddy fields which could ultimately affect methanogenesis, methane oxidation, and methane emission. Understanding interrelated factors affecting methane emission helps create ways to mitigate their impact on global warming and climate change.

Research on Relationship between Urbanization and Energy Consumption (중국의 도시화와 에너지 소비 관계에 대한 연구)

  • Won, Doohwan;Jung, Sukwan
    • Journal of International Area Studies (JIAS)
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    • v.22 no.1
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    • pp.91-112
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    • 2018
  • This study examined the dynamic relationship between urbanization and energy consumption in China. As an alternative to the conventional method of having the same integration of time series and large samples, ARDL method and Toda-Yamamoto causality analysis were applied. As a result, urbanization income, income, and energy consumption have a long-term stable equilibrium. Urbanization and income have a positive effect on energy consumption in the long run, but short-term changes of urbanization and income have no significant effect on energy consumption changes. The adjusted coefficient was -0.2395, which was statistically significant. In the causality test, income and energy consumption are useful to predict each other, but urbanization is exogenous because there are no causality with other variables. Since the process of urbanization in China has been proceeding slowly and deliberately by the government, it can be seen that the long-term effects of urbanization are clear and exogenous.

Structural health monitoring-based dynamic behavior evaluation of a long-span high-speed railway bridge

  • Mei, D.P.
    • Smart Structures and Systems
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    • v.20 no.2
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    • pp.197-205
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    • 2017
  • The dynamic performance of railway bridges under high-speed trains draws the attention of bridge engineers. The vibration issue for long-span bridges under high-speed trains is still not well understood due to lack of validations through structural health monitoring (SHM) data. This paper investigates the correlation between bridge acceleration and train speed based on structural dynamics theory and SHM system from three foci. Firstly, the calculated formula of acceleration response under a series of moving load is deduced for the situation that train length is near the length of the bridge span, the correlation between train speed and acceleration amplitude is analyzed. Secondly, the correlation scatterplots of the speed-acceleration is presented and discussed based on the transverse and vertical acceleration response data of Dashengguan Yangtze River Bridge SHM system. Thirdly, the warning indexes of the bridge performance for correlation scatterplots of speed-acceleration are established. The main conclusions are: (1) The resonance between trains and the bridge is unlikely to happen for long-span bridge, but a multimodal correlation curve between train speed and acceleration amplitude exists after the resonance speed; (2) Based on SHM data, multimodal correlation scatterplots of speed-acceleration exist and they have similar trends with the calculated formula; (3) An envelope line of polylines can be used as early warning indicators of the changes of bridge performance due to the changes of slope of envelope line and peak speed of amplitude. This work also gives several suggestions which lay a foundation for the better design, maintenance and long-term monitoring of a long-span high-speed bridge.

Information Variables for the Predictability of Future Changes in Real Growth (실질 성장의 미래 변화 예측을 위한 정보변수)

  • Kim, Tae Ho;Jung, Jae Hwa;Kim, Min Jeong
    • The Korean Journal of Applied Statistics
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    • v.26 no.2
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    • pp.253-265
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    • 2013
  • It has been interested in developing useful information variables that are able to predict the future movement of final objects to attain the specific policy and strategic target. Term structure of interest rates is known as an important variable to predict future business and economic activity, yet there is little empirical work on the predictability of future changes in real output. This study attempts to develop the statistical model and examine whether domestic term structure of interest rates can predict variations of future cumulative changes in real growth on a long time horizon.

What Happens without Treating Chronic Lateral Ankle Instability (외측 발목 불안정성을 치료하지 않으면 어떻게 되는가)

  • Woo, Seung Hun;Chung, Hyung-Jin
    • Journal of Korean Foot and Ankle Society
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    • v.25 no.1
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    • pp.6-9
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    • 2021
  • The term chronic lateral ankle instability (CLAI) embraces a spectrum of conditions that involve functional and mechanical instability, both in athletes and lower-demand patients. The hallmarks of CLAI are recurrent sprains, persistent pain, and repeated episodes of the ankle giving way. CLAI is the main complication of acute ankle sprains, which can cause discomfort in daily and sports activity. Approximately 10% to 30% of patients with acute ligament ruptures will develop chronic instability over the course of a year from the index injury. An accurate diagnostic approach and successful treatment plan should be established based on a comprehensive understanding of the concept of functional and mechanical instability. Unfortunately, the optimal modality for the management of CLAI is unclear. Even after conservative treatment or surgical intervention, it could result in degenerative changes to the ankle joint in the long term. Thus far, the incidence of ligamentous posttraumatic ankle osteoarthritis was reported to be 13% to 78%. The mean latency time between injury and osteoarthritis was at least 10 to 34.3 years. CLAI is an important pathological condition that can cause discomfort or dysfunction in daily activity in the short term, resulting in joint destruction in the long term. Therefore, it is important to understand the various complications that can occur when CLAI is not treated properly.

Effect of Muscle Strength Training on Urinary Incontinence and Physical Function: A Randomized Controlled Trial in Long-term Care Facilities (시설거주 노인여성을 위한 근력강화 훈련이 요실금과 신체기능에 미치는 효과)

  • Kang, Hyekyung;HongSon, Gwi-Ryung
    • Journal of Korean Academy of Nursing
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    • v.45 no.1
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    • pp.35-45
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    • 2015
  • Purpose: This study was done to determine whether muscle strength training programs have an impact on improving symptoms of urinary incontinence (UI) and physical function among elderly women with UI who reside in long-term care facilities. Methods: A randomized controlled trial was conducted. Participants had to be over 65 years, score over 15 score on the mini-mental state examination, and be able to walk alone or with an assistant. Seventy residents were randomly allocated to either the training group (n=35) or control group (n=35). The program consisted of 50 minutes, twice a week for 8 weeks, and included Kegel's exercise, Thera-band training and indoor walking. Main outcomes were UI symptoms, peak vaginal pressure and physical functions measured with timed up and go test (TUG), one leg standing test (OLST), activities of daily living (ADL) and grip strength. Changes in outcome measurements were calculated from baseline to 4 weeks and to 8 weeks using repeated measures ANOVA. Results: There were significant differences in peak vaginal pressure (p<.001), TUG (p<.001), OLST (p=.012) and grip strength (p<.001) in the interaction between groups and time. Conclusion: Future studies are suggested to confirm the effect of muscle strength training in long-term care facilities where elderly women with UI reside.

The effect of a nutritional education program on the nutritional status of elderly patients in a long-term care hospital in Jeollanamdo province: health behavior, dietary behavior, nutrition risk level and nutrient intake

  • Kim, Bok-Hee;Kim, Mi-Ju;Lee, Yoon-Na
    • Nutrition Research and Practice
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    • v.6 no.1
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    • pp.35-44
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    • 2012
  • This study was conducted to assess improvements in nutritional status following the application of nutrition education to elderly patients in a long-term care hospital. The study was carried out from January to May 2009, during which a preliminary survey, a pretest, the application of nutrition education, and a post-test were applied in stages. The number of subjects at pretest was 81, and the number of participants included in the final analysis was 61 (18 men, 43 women), all of whom participated in both the nutrition education program and the post-test. The survey consisted of general demographic items, health behaviors, dietary behaviors, the Nutrition Screening Initiative checklist, and nutrient intake assessment (24 hour recall method). The nutrition education program lasted for four weeks. It included a basic education program, provided once a week, and mini-education program, which was offered daily during lunch times. The survey was conducted before and after the education program using the same assessment method, although some items were included only at pretest. When analyzing the changes in elderly patients after the nutritional education program, we found that, among subjective dietary behaviors, self-rated perceptions of health (P<0.001) and of depression (P<0.001) improved significantly and that dietary behavior scores also improved significantly (P<0.001), while nutritional risk levels decreased. In terms of nutrient intake, subjects' intake of energy, protein, fat, carbohydrate, calcium, phosphorus, iron, vitamin A, thiamin, riboflavin, niacin, and vitamin C all increased significantly (P<0.001). These results indicated that nutritional education is effective in improving the nutritional status of elderly patients. We hope that the results of this study can be used as preliminary data for establishing guidelines for nutrition management tailored to elderly patients in long-term care hospitals.

STABILITY OF SIMULTANEOUS MAXILLARY AND MANDIBULAR SURGERY;[Ⅰ]Wire osteosynthesis (상하악 동시 악교정술시 안정성에 관한 연구;[Ⅰ] 강선 고정에 의한 방법)

  • Kim, Yeo-Gab
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.12 no.2
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    • pp.9-20
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    • 1990
  • A series of 19 cases with maxillary hyperplasia and mandibular retrognathia were operated on by simultaneous superior repositioning of the maxilla after Le Fort I osteotomy and anterior repositioning of the mandible after bilateral sagittal split ramus osteotomies with or without osteotomy of the inferior border of the mandible. These were evaluated by retrospective cephalometric and computer analysis for the longitudinal skeletal and dental changes for an average of 17.1 months after surgery. For stabilization of the osteotomized segments, the authors used wire osteosynthesis by means of bilateral infraorbital and zygomatic buttress suspension wire at the maxilla, and direct interosseous wire at the split segments of the mandibular rami. Results show generally good stability after simultaneous maxillary and mandibular surgery with wire osteosynthesis, and a minimal to moderate tendency toward skeletal and dental relapse. This article is a preliminary study to defy the efficiency of the wire osteosynthesis (wo)compared with rigid internal fixation (RIF) for simultaneous maxillary and mandibular surgery. 1. The vertical relapse rate of the A point after superior repositioning of the maxilla is 2.2%. 2. The horizontal relapse rate of the B point after advancement of the mandible is 18.3%. 3. The condyle is distracted inferiorly and slightly posteriorly at the immediate postoperative period. 4. At the long term follow up examination, the condyle presents tendency of return to the preoperative position. 5. Condylar segment angle is decreased at the immediate postoperative period, and at the long term follow up evaluation, the angle is increased. 6. Gonial angle is increased at the immediate postoperative period, and then is decreased at the long term follow up evaluation. 7. The dentition is satisfactory with acceptable movement at the long term follow up evaluation. 8. At the mandibular free body analysis, genioplasty shows good stability. 9. Wire osteosynthesis provides excellent stabilization for the simultaneous maxillary and mandibular surgery.

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Construction Monitoring Methods of FCM Bridge Using Temperature Data (온도데이터를 활용한 현장타설 캔틸레버 교량의 시공 중 계측)

  • Kim, Hyun-Joong;Moon, Dae Joong;Nam, Soon Sung;Jeong, Ju Yong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.3
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    • pp.219-227
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    • 2016
  • In this study, we have proposed a method of monitoring of bridges under construction in view of the long-term behavior of the prestress concrete bridge of which the Free Cantilever Method is applied. As a method to confirm the ability of the long-term behavior of the concrete box girder, temperature sensors and strain gauges were installed, and the measured data was used to calculate creep coefficient. Moreover, we have measured the stress of the concrete box girder during construction which was applied with creep coefficient and compared with the changes in temperature to analyze the vertical displacement along the segment. In conclusion, monitoring of the FCM bridge during construction in consideration of the long-term behavior can be analyzed efficiently by suing temperature and displacement data without the use of laser displacement meter or laser delfectometer.