• 한국물환경학회지
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• 제28권4호
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• pp.561-573
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• 2012

The object of this study was to analyze long-term water quality gradients during 1992-2008 at six sites of Geumho River and near-by two sites of Nakdong River and their influences on fish trophic guilds and tolerance guilds along with ecological health. Water quality including biological oxygen demand (BOD), chemical oxygen demand (COD), conductivity, total phosphorus (TP), total nitrogen (TN), and total suspended solids (TSS) varied largely depending on the sampling locations and seasons. Values of ambient BOD, COD, TP, and TN were greater in the downstream than in the upstream reach, and seasonal and interannual variabilities were also higher in the downstreams. This phenomenon was evident due to a dilution by the Asian monsoon rainfall during the monsoon. These outcomes indicate that point sources near the downstream are important for the chemical conditions, but also seasonal stream runoff was considered as an important factor regulating the chemical conditions. Conductivity decreased rapidly during the summer due to ionic dilution, and nutrients (N, P), BOD, COD had an inverse function of seasonal precipitation. Based on the water quality, we selected two sites (control site = $C_s$ vs. impacted site = $I_s$) for impact analysis of water chemistry on fish community and trophic/tolerant guilds. Fish guild analysis showed that species diversity was higher in the headwater stream ($C_s$) than the impacted downstream ($I_s$), and that the proportion of tolerant and omnivore species were greater in the impacted site of downstream. Comparisons of water quality between Geumho River and Nakdong River indicated that Geumho River was considered as a point source which degradated water quality to the Nakdong River. Overall, chemical water quality and fish guild analysis suggest that even if current chemical quality got better after 1996 due to continuous constructions of wastewater disposal plants near the downstreams, fish compositions of tolerant and omnivores were still dominated the community. Thus, biological restoration based on ecological health is required for the ecosystem conservation.

• 한국환경과학회지
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• 제23권8호
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• pp.1513-1522
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• 2014

Fish passage asssessments were conducted in the fishway at Juksan Weir, which was constructed as a four-major rivers project in the downstream area of Youngsan-River Watershed. For the research, fish-movements/migrations were analyzed for seven times from April ~ October, 2013 using an approach of fish trap-setting. Fish fauna and compositions were analyzed in the fishway, and seasonal- and diel-movement patterns were analyzed in relation to current velocity in the fishway. Also, abundances of exotic fishes such as bluegill sunfish (Lepomis macrochirus), large-mouth bass (Micropterus salmoides), and white curcian carp (Carassius cuvieri) were monitored in the fishway. Current velocity(n = 18) in the fishway showed large variations ($0.82{\pm}0.63m/s$) depending on the location of the fish trap-setting and this physical factor influenced the fish movements. Fish movements, based on the CPUE of individuals, in the fishway was greater in slower velocity (mean: 0.36 m/s, range: 0.10~1.54 m/s) than faster velocity (mean: 1.51 m/s, range: 0.90~1.90 m/s). Seasonal analysis of fish movements showed that most frequent uses (8 speices and 591 individuals, 66.2% of the total) of the fishway occurred in spring period(i.e., June). Diel movement analysis, in the mean time, showed highest in the time period of 00:00 ~ 3:00 am (7 species and 281 individuals, 20.9% of the total). The efficient managements in the fishway at Juksan Weir are required in relation to the hydrological regime.

• 한국발생생물학회지:발생과생식
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• 제14권2호
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• pp.131-141
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• 2010

이 연구는 양식산 넙치의 성장단계별 및 계절에 따른 생리학적 반응과 혈액학적 요소들을 파악하고자 하였으며, 분석된 항목으로는 hematocrit, red blood cell, hemoglobin, 글루코스, 콜레스테롤, 총단백질, AST, ALT, $Na^+,\;K^+,\;Cl^-,\;Ca^{2+},\;Mg^{2+}$, osmolality, 코티졸 및 $T_3$였다. 성장단계별 혈액학적 성상에 있어 $T_3$는 어류의 크기가 클수록 증가하는 경향을 나타내었다. 반면, 콜레스테롤은 어체의 크기가 클수록 감소하는 경향을 보였다. 계절별 혈액학적 성상에 있어 Ht와 RBC는 가을에 가장 높은 수준을 나타냈다. 코티졸은 모든 그룹에서 $2.2{\pm}0.4{\sim}4.3{\pm}1.9ng/m{\ell}$의 농도를 보였다. 나머지 혈액학적 요소는 성장단계별, 계절별로 특이한 차이를 나타내지 않았다. 본 연구에서 분석 비교한 각종 혈액학적 요소의 측정값은 양식산 넙치의 생리활성 평가에 활용될 수 있을 것으로 기대된다.

• 콘크리트학회논문집
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• 제22권6호
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• pp.769-776
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• 2010

해수에 침적되어 있는 구조물은 일정한 외부 염화물 조건을 가지게 되지만 비래염분의 환경하에 있는 콘크리트 구조물은 지역, 해안으로부터 거리, 구조물의 방향, 풍향 등 주변환경에 따라서 다양한 조건의 외부 염화물 조건을 갖게 된다. 따라서, 해수와 직접 접하지 않더라도 지역적인 특성에 따라 비래염분에 의한 염해를 받을 수 있으며, 그러한 사례들이 보고되고 있다. 그러나, 이러한 비래염분 환경조건을 규명하기는 쉽지 않아 이제까지는 많은 연구가 행하여 지지 못하였다. 따라서, 이 연구에서는 우리나라의 해안가 27개 지역 72개 지점을 선정하여 3년간 대기중의 비래염분에 대한 측정을 실시하여 분석하였다. 그 결과, 비래염분은 지역적 특성이 강하게 나타났으며, 계절적인 영향 또한 크게 나타났다. 또한, 해안으로부터 거리에 따라서 $y=ax^{-b}$의 함수의 경향으로 감소하는 것으로 밝혀졌다. 이러한 비래염분 분포에 대한 분석결과는 향후 해안 인근 구조물의 내구성 설계나 유지관리에 큰 도움이 될 것으로 판단된다.

• 생물환경조절학회지
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• 제24권1호
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• pp.1-7
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• 2015

파프리카는 수분에 민감한 작물이므로 작물의 생산성 향상을 위하여 적정 관수조절은 매우 중요하다. 광환경 조건은 시설재배에서 여러 환경 변수 중 조절이 용이하지 못하며, 지역 별, 계절 별 분포가 다르기 때문에 광환경 데이터를 이용한 증산과 관수의 추정이 필요하다. 본 연구에서는 파프리카의 정확한 증산 예측을 위하여 변형된 증산 추정식을 활용하였다. 또한 기상청의 광도자료를 활용하여 지역 별 증산량과 관수량을 비교하였다. 우리나라의 경우 여름철 하루 중 광도의 편차가 심하고 장마기간이 있으므로 봄, 가을에 비하여 증산량이 오히려 낮았다. 그리고 광주기가 길어지는 봄에 증산량이 가장 많았으므로, 이 시기의 데이터를 이용하여 관수시설 용량을 지역별로 제시할 수 있었다. 이러한 결과는 시설재배에서 관수설비 기준제시를 위한 자료 및 투입에너지 최적화에도 유용하게 활용될 것으로 판단된다.

• 한국환경보건학회지
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• 제42권1호
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• pp.19-26
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• 2016

Objectives: This study aimed to assess temporal changes in the level of culturable airborne fungi (CAF) in three microbiology laboratories and determine the environmental factors associated with CAF level. Methods: CAF levels were determined once per month from March 2011 to February 2012 in three microbiology laboratories. An Andersen one-stage sampler was used for five minutes, three times per day to collect the CAF. Arithmetic means of CAF concentrations and standard deviation (SD) were calculated. A Mann-Whitney test was applied to compare the differences between environmental factors such as divided room by structure of laboratory, use of humidifier, and use of air-conditioner. Correlation analysis was also applied to identify the association between CAF concentrations and environmental factors. Results: CAF levels demonstrated an increasing tendency in summer, and the three laboratories showed consistent seasonal patterns. Temperature and relative humidity (RH) were associated with CAF levels. When the humidifier was off, CAF concentrations were significantly higher in study rooms than in study rooms in which the humidifier was on. Conclusion: CAF levels in indoor microbiology laboratories varied greatly depending upon the temperature and RH and whether a humidifier was used.

• Environmental Engineering Research
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• 제24권1호
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• pp.45-53
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• 2019

Water and soil properties in paddy fields subjected to organic and conventional farming were characterized over the rice cycle in South Korea. To achieve the goals of this study, we sampled and analyzed soil and water from 24 organic paddy plots and 11 conventional paddy plots in March, May, August, and October 2016. The results were analyzed using statistical analyses, including analysis of variance (ANOVA), cluster analysis, and principal component analysis. The ANOVA results showed that water content (WC), electrical conductivity (EC), organic matter (OM), and available phosphorus ($P_2O_5$) in soil varied significantly (p < 0.01) depending on the farming method. Higher OM, EC, and $P_2O_5$ of soil were observed in the conventional paddies than in the organic paddies. All soil properties, except pH and ammonium, depended on seasonal variation. Cluster analysis revealed that soil properties in May were distinctly separated from those in other seasons mainly due to basal fertilization. The principal component analysis distinguished the soil properties in different seasons, but such a distinction was not observed between the soil properties in organic and conventional paddies. Low contents of WC, OM, and total N were observed in March. High concentrations of nitrate and total P were observed in May, but these were low in August and October. The soils from October were also characterized by high concentrations of EC and $P_2O_5$. These results indicate that the sampling time for soil and water can significantly influence the evaluation of soil properties with different farming methods.

• Psychiatry investigation
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• 제15권12호
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• pp.1188-1202
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• 2018

Objective This study protocol aims to determine, using a rigorous approach in patients with bipolar disorder (BD) and non-seasonal major depressive episode (MDE), the characteristics of bright light therapy (BLT) administration (duration, escalation, morning and mid-day exposures) depending on the tolerance (hypomanic symptoms). Methods Patients with BD I or II and treated by a mood stabilizer are eligible. After 1 week of placebo, patients are randomized between either morning or mid-day exposure for 10 weeks of active BLT with glasses using a dose escalation at 7.5, 10, 15, 30 and 45 minutes/day. A further follow-up visit is planned 6 months after inclusion. Patients will be included by cohorts of 3, with at least 3 days of delay between them, and 1 week between cohorts. If none meet a dose limiting toxicity (DLT; i.e hypomanic symptoms), the initiation dose of the next cohort will be increased. If one patient meet a DLT, an additionnal cohort will start at the same dose. If 2 or 3 patients meet a DLT, from the same cohort or from two cohorts at the same dose initiation, the maximum tolerated dose is defined. This dose escalation will also take into account DLTs observed during the intra-subject escalation on previous cohorts, with a "Target Ceiling Dose" defined if 2 DLTs occured at a dose. Discussion Using an innovative and more ergonomic device in the form of glasses, this study aims to better codify the use of BLT in BD to ensure a good initiation and tolerance.

• 한국수산과학회지
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• 제54권3호
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• pp.329-339
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• 2021

The monthly variation in species composition of fishes in the Gujora and Mangchi coastal waters in Geoje, Korea, was investigated between June 2018 and May 2019 through monthly fish collections using a gill net. A total of 46 species, numbering 410 individuals weighing a total of 96,645.0 g, were collected during the study period. The dominant species in terms of numbers were Chelidonichthys spinosus, Stephanolepis cirrhifer, Ditrema temmincki, Sillago japonica, Sebastes inermis, and Paraplagusia japonica. The number and biomass of fishes peaked in July. The peak in species diversity indices occurred in September. The cluster analysis revealed that there were four groups of fishes depending on the season. In addition, subtropical fishes were recorded in the study area, indicating the gradual subtropicalization of the coast of Geoje. Furthermore, the need to understand the changes in marine ecosystems owing to subtropicalization through continuous monitoring is emphasized.

• 대한안전경영과학회지
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• 제20권2호
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• pp.9-20
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• 2018

This study is empirically intended to look into the effects of HVAC management on condensation cause and prevention in indoor swimming pools. The findings are summarized as follows. First, the experience of condensation in indoor swimming pools showed that 132 out of 142 people in total experienced the condensation in indoor swimming pools, which they had a high experience rate of 92.3%. For the location of condensation, the wall joints were 46.8% and the windows were 34.5%, which a total of 72.3% occurred in the wall joints and windows. Second, the effect of construction design, HVAC management and building construction on the cause of condensation in indoor swimming pools showed that building construction had an effect on the cause and location of condensation depending on the seasonal time, partially adopting hypothesis 1. Third, the effect of condensation-causing factors on condensation-preventing factors in indoor swimming pools showed that condensation had a close relationship with air and temperature conditions depending on the time and location of condensation, adopting hypothesis 2. As for the above-stated findings, the HVAC management in indoor swimming pools is an important concern factor that continues to cause condensation despite the development of advanced construction materials. Especially, building construction is a main factor that has a direct effect on condensation in the HVAC management of facilities. This implies that the window management is important in maintaining the wall joints - which can suppress the selective use and defect occurrence of construction materials - or confined spaces for a long time.