• Childhood Kidney Diseases
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• v.11 no.1
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• pp.74-82
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• 2007

Purpose : To analyze the clinical characteristics, spontaneous resolution rate and predictive factors of resolution in children with primary vesicoureteral reflux(VUR). Methods : Between October 1991 and July 2003, 149 children diagnosed with primary VUR at Chonbuk National University Hospital were reviewed retrospectively. All of the patients were maintained on low-dose antibiotic prophylaxis and underwent radionuclide cystograms at 1 year intervals over 3 years after the initial diagnosis of VUR by voiding cystourethrogram was made. Results : The median time to resolution of VUR was 24 months and the total 3 year-cumulative resolution rate of VUR was 61.7%. The following variables were associated with resolution of VUR according to univariate analysis-; age<1 year, male gender, mild grade of reflux, unilateral reflux, congenital hydronephrosis as clinical presentation at time of diagnosis of VUR, absence of focal defects in the renal scan at diagnosis, absence of recurrent UTI, renal scars and small kidney during follow-up. After adjustment by Cox regression model, five variables remained as independent predictors of VUR resolution; age<1 yew, relative risk 1.77(P<0.05), VUR grade I+II 2.98(P<0.05), absence of renal scars 2.23(P<0.05), and absence of small kidney 5.20(P<0.01) during follow-up. Conclusion : In this study, spontaneous resolution rate of VUR, even high grade reflux, is high in infants during medical management, and it was related to age, reflux grade at diagnosis, absence of renal scars and small kidney during follow-up. Therefore early surgical intervention should be avoided and reserved for the selected groups.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.8
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• pp.870-876
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• 2005

The multiple regression models which have two factors(population and commercial area) have been used to forecast the water demand in the future. But, the coefficient of population had a negative value because proper regional classification wasn't performed, and it is not reasonable because the population must be a positive factor. So, the regional classification was performed by principal component and cluster analysis to solve the problem. 6 regional characters were transformed into 4 principal components, and the areas were divided into two groups according to cluster analysis which had 4 principal components. The new regression models were made by each group, and the problem was solved. And, the future water demands were estimated by three scenarios(Active, moderate, and passive one). The increase of water demand ore $89.034\;m^3/day$ in active plat $49,077\;m^3/day$ in moderate plan, and $19,996\;m^3/day$ in passive plan. The water supply ability as scenarios is enough in water treatment plant, however, 2 reservoirs among 4 reservoirs don't have enough retention time in all scenarios.

• Journal of Environmental Impact Assessment
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• v.26 no.6
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• pp.553-562
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• 2017

In these days, agricultural reservoirs are considered as a useful resource for recreational purposes, tour and cultural amenity for vicinity communities as well as irrigation water supply. However, many of the agricultural reservoirs are showing a eutrophic or hyper-eutrophic state and high level of organic contamination. In particular, about 44.7% of the aged agricultural reservoirs that constructed before 1945 exceed the water quality criteria for irrigational water use. In addition to external loading, internal nutrient loading from bottom sediment may play an important role in the nutrient budget of the aged reservoirs. The objectives of this study were to characterize variations of thermal structure of a shallow M reservoir (mean depth 1.7 m) and examine the potential of internal nutrient loading by continuous monitoring of vertical water temperature and dissolved oxygen (DO) concentration profiles in 2015 and 2016. The effect of internal loading on the total loading of the reservoir was evaluated by mass balance analysis. Results showed that a weak thermal stratification and a strong DO stratification were developed in the shallow M Reservoir. And, dynamic temporal variation in DO was observed at the bottom of the reservoir. Persistent hypoxic conditions (DO concentrations less than 2 mg/L) were established for 87 days and 98 days in 2015 and 2016, respectively, during the no-rainy summer periods. The DO concentrations intermittently increased during several events of atmospheric temperature drop and rainfall. According to the mass balance analysis, the amount of internal $PO_4-P$ loading from sediment to the overlying water were 37.9% and 39.7% of total loading during no-rainy season in 2015 and 2016, respectively on August when algae growth is enhanced with increasing water temperature. Consequently, supply of DO to the lower layer of the reservoir could be effective countermeasure to reduce nutrient release under the condition of persistent DO depletion in the bottom of the reservoir.

• Korean Journal of Culture and Social Issue
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• v.24 no.2
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• pp.273-300
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• 2018

In order to analyze the experience of women from the provinces settling in Seoul, the current study conducts in-depth interviews on seven women who are working in Seoul after coming up to Seoul to attend and graduate from university. The results of the interview were analyzed using grounded theory methodology, under which the open coding extracted one hundred ten concepts, twenty-one sub-categories, and eleven categories encompassing them all. Causal condition is 'difficulty of settling in Seoul' and contextual conditions are 'intensification of psychological anxiety', 'reduction in quality of life', and 'continuation of economic instability'. The central phenomenon is 'dilemma of continuing life in Seoul' and intervening condition is 'diagnosis of ten years after coming up to Seoul'. Action/interaction strategies are 'changes in personal life', 'securing economic abilities through a stable job', and 'finding ways to participate in the society', while the result was 'choosing whether to continue living in Seoul'. The paradigm of experience of women from the provinces settling in Seoul proceed from coming up to Seoul for university to becoming independent, adapting to life in the city, experiencing growth and failures, facing challenge and searching for solutions, and conducting self-evaluation and making new choices. The participants reported that they were aware of differences and experienced anxieties as a stranger in Seoul even after living in the city for ten years; the problems they face have become more complex and diverse since when they were in university, and while they launched a career and making money, the gap between them and their peers from Seoul has not closed. The women also express desperation that they may need to leave Seoul to find alternatives to problems caused by accumulated stress and social problems that cannot be solved by an individual. In conclusion, the current study confirmed that efforts by individuals can only have limited effects in helping women from the provinces to settle in Seoul, indicating that detailed policy plans are required to solve social issues in the overall Korean society.

• Atmosphere
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• v.24 no.3
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• pp.303-315
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• 2014

Terrestrial ecosystem plays the important role as carbon sink in the global carbon cycle. Understanding of interactions of terrestrial carbon cycle with climate is important for better prediction of future climate change. In this paper, terrestrial carbon cycle is investigated by Hadley Centre Global Environmental Model, version 2, Carbon Cycle (HadGEM2-CC) that considers vegetation dynamics and an interactive carbon cycle with climate. The simulation for future projection is based on the three (8.5/4.5/2.6) representative concentration pathways (RCPs) from 2006 to 2100 and compared with historical land carbon uptake from 1979 to 2005. Projected changes in ecological features such as production, respiration, net ecosystem exchange and climate condition show similar pattern in three RCPs, while the response amplitude in each RCPs are different. For all RCP scenarios, temperature and precipitation increase with rising of the atmospheric $CO_2$. Such climate conditions are favorable for vegetation growth and extension, causing future increase of terrestrial carbon uptakes in all RCPs. At the end of 21st century, the global average of gross and net primary productions and respiration increase in all RCPs and terrestrial ecosystem remains as carbon sink. This enhancement of land $CO_2$ uptake is attributed by the vegetated area expansion, increasing LAI, and early onset of growing season. After mid-21st century, temperature rising leads to excessive increase of soil respiration than net primary production and thus the terrestrial carbon uptake begins to fall since that time. Regionally the NEE average value of East-Asia ($90^{\circ}E-140^{\circ}E$, $20^{\circ}N{\sim}60^{\circ}N$) area is bigger than that of the same latitude band. In the end-$21^{st}$ the NEE mean values in East-Asia area are $-2.09PgC\;yr^{-1}$, $-1.12PgC\;yr^{-1}$, $-0.47PgC\;yr^{-1}$ and zonal mean NEEs of the same latitude region are $-1.12PgC\;yr^{-1}$, $-0.55PgC\;yr^{-1}$, $-0.17PgC\;yr^{-1}$ for RCP 8.5, 4.5, 2.6.

• Korean Journal of Environmental Agriculture
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• v.22 no.4
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• pp.278-283
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• 2003

This study was carried out to examine the nitrogen removal rate of a subsurface-flow treatment wetland system which was constructed on floodplain of the Kwangju River from May to June 2001. Its dimensions were 29m in length, 9m in width and 0.65m in depth. A bottom layer of 45cm in depth was filled with crushed granite with about $15{\sim}30\;mm$ in diameter and a middle layer of 10cm in depth had pea pebbles with about 10 mm in diameter. An upper layer of 5 cm in depth contained course sand. Reeds (Phragmites australis) were transplanted on the surface of the system. They were dug out of natural wetlands and stems were cut at about 40 cm height from their bottom ends. Water of the Kwangju River flowed into it via a pipe by gravity flow and its effluent was funneled back into the river. The height of reed stems was 44.2 cm in July 2001 and 75.3cm in September 2001. The number of stems was increased from $80\;stems/m^2$ in July 2001 to $136\;stems/m^2$ in September 2001. Volume and water quality of inflow and outflow were analyzed from July 2001 through December 2001. Inflow and outflow averaged 40.0 and $39.2\;m^3/day$, respectively. Hydraulic detention time was about 1.5 days. Average nitrogen uptake by reeds was $69.31\;N\;mg/m^2/day$. Removal rate of $NO_3-N$, $NH_3-N$, T-N averaged 195.58, 53.65, and $628.44\;mg/m^2/day$, respectively. Changes of $NO_3-N$ and $NH_3-N$ abatement rates were closely related to those of wetland temperatures. The lower removal rate of nitrogen species compared with that of subsurface-flow wetlands operating in North America could be attributed to the initial stage of the system and inclusion of two cold months into the six-month monitoring period. Increase of standing density of reeds within a few years will develop both root zones suitable for the nitrification of ammonia and surface layer substrates beneficial to the denitrification of nitrates into nitrogen gases, which may lead to increment in the nitrogen retention rate.