• Fisheries and Aquatic Sciences
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• 제17권3호
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• pp.345-353
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• 2014

Copper has been widely used to control algae and pathogens in fish culture ponds. However, its toxic effects on fish depend not only on its concentration in the water but also on the water quality. A laboratory experiment was conducted to assess copper toxicity in the black rockfish Sebastes schlegeli using a panel of antioxidant enzymes, including glutathione (GSH), glutathione S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR) and superoxide dismutase (SOD), at different levels of copper at three water temperatures (WT, 18, 23, $28^{\circ}C$) for 4 days. After exposure to two copper concentrations (100 and $200{\mu}g/L$), GSH levels and GST activities increased significantly, depending on WT (P < 0.05) in the liver, gill, and kidney of the black rockfish. GPx and SOD activities decreased significantly with both increasing WT and copper treatment in the organs of black rockfish (P < 0.05). These changes can be seen as initial responses to temperature stress and as a sustained response to copper exposure. This also indicates that GSH and related enzymes activities were sensitive indexes to stress by toxicants such as copper. The present findings suggest that simultaneous stress due to temperature change and copper exposure can accelerate changes in enzymes activities in the black rockfish. This provides another example of synergism between environmental temperature and pollutants, which may have important implications for the survival of fish in polluted environments during seasonal warming and/or global climate change.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.247-247
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• 2023

Coastal lagoons play a crucial role in water exchange, water quality, and biodiversity. It is essential to monitor and understand the dynamics of hydrogeochemistry in lagoon water and its groundwater to preserve and sustainably manage the groundwater-dependent ecosystems like coastal lagoons. This study investigated the spatial and temporal hydrogeochemical characteristics of coastal lagoon (Songjiho) and groundwater on the east coast of Korea. The concentrations of major ions, water isotopes, and nutrients (nitrogen and dissolved organic carbon) in lagoon water and groundwater were periodically monitored for one year. The study revealed that major ions and total dissolved solids (TDS) concentration were higher at deeper depths of aquifers and closer to the coastal area. The hydrogeochemical characteristics of coastal lagoon and groundwater chemistry were classified into two types, Ca-Mg-HCO₃ and Na-Cl, based on their spatial location from inland to coastal area. Moreover, the hydrogeochemical characteristics of coastal lagoons and groundwater varied significantly depending on the season. During the wet season, the increased precipitation and evaporation lead to changes in water chemistry. As a result, the total organic carbon (TOC) of coastal lagoons increases during this season, likely due to increased runoff by rainfall whereas the variation of chemical compositions in the lagoon and groundwater were not significant because there is reduced precipitation, resulting in stable water levels and during the dry season. The study emphasizes the impact of spatial distribution and seasonal changes in precipitation, evaporation, and river discharge on the hydrogeochemical characteristics of the coastal aquifer and lagoon system. Understanding these impacts is crucial for managing and protecting coastal lagoons and groundwater resources.

• 한국응용곤충학회지
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• 제38권1호
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• pp.41-46
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• 1999

본 연구는 국내 느타리버섯 재배지에 발생하는 주요 버섯파리류를 조사하고, 이의 지역별.시기별 발생양상을 조사하였다. 버섯파리류 조사는 1997년 여름버섯재배기인 7~8월과 가을 버섯재배기인 10~11월의 2회에 걸쳐 전국 16곳의 주요 느타리버섯 재배지에서 실시하였다. 그 결과, 국내 느타리버섯 재배지에 발생하여 버섯에 피해를 가하는 버섯파리류로서 주용 3종인 Sciaridae, Cecidomyiidae 및 Scatopsidae 파리류를 포함하여 6종이 조사되었으며, 지역 및 시기에 따라 다소 차이가 있었다. 그중 Lycoriella mali(Diptera:Sciaridae)는 전국적으로 연중 발생하여 가장 문제시 되는 해충으로 조사되었다. 또 Coboldia fuscipes(Diptera:Scatopsidae)는 유충이 버섯균사를 가해하였으며, 주로 7~8월에 대량 발생한 후 가을에는 그 발생량이 감소하였다. 또한 유생생식을 하는 Mycophila sp. (Diptera:Cecidomyiidae)에 의한 균상 및 느타리버섯의 오염이 전국적으로 관찰되었는데, 특히 10~11월에 대량발생과 함께 그 피해가 극심하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권6호
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• pp.625-631
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• 2014

본 연구에서는 최근 LNG를 사용하는 화력발전소가 증가함에 따라 등장한 LNG-FSRU (Floating Storage Regasification Unit)에서 LNG를 육상에 있는 소비자에게 기체 상태로 전달하기 위해 Topside에 설치된 재기화 시스템의 열원온도 및 기화성능의 변동에 따른 시스템의 특성분석에 관한 연구이다. 시스템 특성분석을 위하여 LNG가 재기화 할 때 필요한 열원으로써 해수를 사용하는 기화방식과 에틸렌글리콜을 사용하는 기화방식으로 나누어 $-157.9^{\circ}C$, 10,400kPa의 LNG를 시간당 200ton 기화시키는 시스템을 구성하였고, 이때 공급되는 해수온도에 따라 필요한 해수의 최소유량 값을 구하였다. 그리고 에틸렌글리콜을 사용하는 기화방식에서는 지역 및 계절 등의 요인으로 인해 해수온도가 낮아질 경우를 대비하여 $174.5^{\circ}C$, 775kPa의 보일러 스팀을 추가열원으로 설치된 시스템을 구성하고, 필요한 스팀의 생성량을 기화성능에 따라 비교분석함으로써 해수온도 변화에 따라 요구되는 보일러 스팀의 양과 기화성능의 변화에 따른 해수 및 에틸렌글리콜 그리고 스팀의 양을 구하였다.

• 한국환경보건학회지
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• 제50권1호
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• pp.16-24
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• 2024

Background: Indoor PM_2.5 concentrations in residential houses can be affected by various factors depending on the season. This is because not only do the climate characteristics depend on the season, but the activity patterns of occupants are also different. Objectives: The purpose of this study is to compare factors affecting indoor PM_2.5 concentrations in apartments and detached houses in Daegu according to seasonal changes. Methods: This study included 20 households in Daegu, South Korea. The study was conducted during the summer (from July 10 to August 10, 2023) and the autumn (from September 11 to October 9, 2023). A sensor-based instrument for PM_2.5 levels was installed in the living room of each residence, and measurements were taken continuously for 24 hours at intervals of one minute during the measurement period. Based on the air quality monitoring system data in Daegu, outdoor PM_2.5 concentrations were estimated using ordinary kriging (OK) in Python. In addition, the indoor activities of the occupants were investigated using a time-activity pattern diary. The affecting factors of indoor PM_2.5 concentration were analyzed using multiple regression analysis. Results: Indoor and outdoor PM_2.5 concentrations of the residences during summer were 15.27±11.09 ㎍/m³ and 11.52±7.56 ㎍/m³, respectively. Indoor and outdoor PM_2.5 concentrations during autumn were 13.82±9.61 ㎍/m³ and 9.57±5.50 ㎍/m³, respectively. The PM_2.5 concentrations were higher in summer compared to autumn both indoors and outdoors. The primary factor affecting indoor PM_2.5 concentration in summer was occupant activity. On the other hand, during the autumn season, the primary affecting factor was outdoor PM_2.5 concentration. Conclusions: Indoor PM_2.5 concentration in residential houses is affected by occupant activity such as the inflow of outdoor PM_2.5 concentration, cooking, and cleaning, as found in previous studies. However, it was revealed that there were differences depending on the season.

• 한국식품저장유통학회지
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• 제23권4호
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• pp.502-509
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• 2016

본 연구에서는 우리나라 토종 선인장인 천년초(Opuntia humifusa)의 줄기를 계절에 따라 채취하여 외관 및 성분을 비교하였다. 계절별 시료 간 외형을 장축, 단축, 폭, 중량의 항목으로 구분하여 측정, 비교하였으며, 색도를 측정하여 외관을 비교하였다. 외형은 겨울 천년초 줄기가 여름 천년초 줄기에 비해 작았고, 단축 대비 장축의 비가 겨울 1.39, 봄 1.67, 여름 1.71 순으로 나타났다. 중량 또한 여름 천년초 줄기가 평균 40.51 g으로 가장 무거웠다. 건조를 하지 않은 천년초 줄기 생시료의 수분함량은 여름 천년초 줄기가 86.86%로 가장 높았고, 유의수준에서 봄, 겨울 순으로 수분함량이 줄어드는 경향을 나타냈다. 색도의 경우 L값은 여름 천년초 줄기가 73.20으로 유의적 수준에서 가장 높았으며, a값과 b값은 봄 천년초 줄기가 가장 높았다. 일반성분의 함량은 여름 천년초 줄기가 조단백과 조지방이 유의적으로 가장 낮고 조회분의 경우 유의적으로 가장 높아 타 계절의 시료와 차이를 보였다. 식이섬유 함량 또한 여름 천년초 줄기가 67.18%로 가장 높았고, 봄, 겨울 순으로 유의적인 차이를 보였으며, 그 함량이 알로에와 같은 특용작물이나 과일, 채소류, 해조류보다 높은 수준으로 나타났다. 무기질 함량은 칼슘이 4,745.09 mg%로 가장 높았고, 모든 시료가 각 항목에서 유의적으로 계절에 따른 시료의 무기질 함량차이를 보였다. 구성아미노산의 함량은 전체 합이 여름 천년초 줄기가 3,386.36 mg%로 가장 적었고, 봄 천년초 줄기가 5,463.86 mg%로 가장 높았다. 모든 시료에서 glutamic acid, aspartic acid의 함량이 가장 높은 특징을 보였다. 유리 아미노산 또한 시료 간에 다량 함유된 유리 아미노산의 구성이 유사하였고, 구성아미노산과 유사하게 여름 천년초 줄기의 총 함량이 가장 적어 봄, 겨울의 시료와 차이가 있었다. 본 연구결과 연중 수확이 가능한 천년초의 줄기가 계절에 따라 외관특성 및 성분에 차이를 보이는 것을 확인할 수 있었다. 계절에 따른 천년초 선인장 줄기의 외관특성은 생 천년초 줄기를 이용한 최소가공 제품류의 생산 시 고려될 수 있을 것으로 판단되며, 성분특성의 경우 기능성 식품을 포함한 가공제품의 제조 시 계절별로 차이를 나타내는 기능성분(식이섬유, GABA 등) 함량을 고려할 필요성이 있을 것으로 사료되었다.

• 한국식품영양과학회지
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• 제39권1호
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• pp.99-104
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• 2010

본 연구는 칠면초를 식품 및 공중 보건 소재로 이용하기 위하여 수확계절에 따른 칠면초 추출물의 생리활성의 변화에 대해 연구하였다. 여름에 수확한 칠면초의 총 미네랄 함량은 89.8 g/kg로서 겨울철 칠면초(86.7 g/kg)보다 약간 많은 함량을 나타내었다. 칠면초의 Na 함량은 현저한 계절적 차이를 나타내지 않은 반면에, 여름철 칠면초의 K와 Ca 함량은 겨울철 칠면초에서 50%로 감소하거나 두 배로 증가하였다. 한편, 칠면초 추출물의 항산화 활성은 수확시기에 영향을 받는 것을 알 수 있었다. 여름 칠면초에서는, ethyl acetate 추출물이 가장 높은 DPPH 라디칼 소거능을 나타내었으나, 겨울 칠면초에서는 butanol 추출물이 가장 높은 라디칼 소거능을 나타내었다. 그러나 FRAP value에서는 여름철과 겨울철 칠면초 모두에서 butanol 추출물이 가장 높은 활성을 나타내었다. 추출물의 총 페놀 함량은 항산화 활성에 비례하였다. B16BL6 세포를 이용한 tyrosinase 저해능 실험과 멜라닌 생합성 실험에서 hexane 추출물이 채취 계절에 관계없이 높은 미백 효과를 나타내었다. 본 연구 결과로부터 칠면초를 기능성 소재로서 이용하고자 할 때 추출 시기에 따라 적당한 추출 방법을 선택하여야 할 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제21권10호
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• pp.1466-1472
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• 2008

Variations in conjugated linoleic acid (CLA) concentrations in Holstein dairy cows milk, depending on feeding systems in different seasons was investigated. Milk samples were collected from Holstein dairy cows, which either grazed for whole days (WG), only daylight hours (TG), or were offered a total mixed ration (TMR) and experienced no grazing (NG), from April to December of 2005. In April, November and December, the cows in TG and WG treatments received grass silage and some concentrate, while from May to October, the cows grazed on temperate pasture. The cows in NG treatment received the TMR throughout the season. The major fatty acid obtained in the pastures was linolenic acid. There was no significant difference in the pasture's linolenic acid concentrations from May to September, but there was a significant decrease in October. However, the linolenic acid concentrations obtained in the pasture were always much higher than those obtained from the TMR. Linoleic acid was also the major fatty acid in the TMR, but these concentrations were higher in the TMR than in the pasture. There was no significant difference in milk cis9trans11CLA (c9t11CLA) concentrations between the three feeding systems while the cows were fed on conserved pasture in April, November and December. Although c9t11CLA concentrations were lower in the TMR, it was found that the cows which grazed in fresh pasture experienced significantly higher concentrations of c9t11CLA in their milk than those which received only TMR. It was also found that cows in the WG treatment experienced higher c9t11CLA concentrations than those in the TG treatment. In the WG and TG treatments, c9t11CLA concentrations were highest in June, after which, they gradually decreased (p<0.01) until October. For the NG treatment, there was no significant change in the concentrations of c9t11CLA (p>0.05) with season. Overall, trans11C18:1 and c9t11CLA were greatly influenced by season, with higher variation in the WG treatment than in the TG treatment and no variation in the NG treatment.

• International Journal of Industrial Entomology and Biomaterials
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• 제18권2호
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• pp.97-103
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• 2009

Sericulturists in the vicinity of Bangalore city irrigate their mulberry gardens with Vrishabhavathy stream water, which is polluted with domestic and industrial wastes from the city. To investigate the effect of pollutants on silkworm crops, a detailed field survey was conducted to study the cocoon yield pattern of the crops raised on mulberry irrigated with wastewater as against irrigation by bore/open wells. The villages along the stream were grouped into five test batches at about a distance of $5{\sim}8$ km from each other. The seasonal yield data with relevant information were collected through questionnaires from 117 rearers using stream water and 35 rearers using bore/open wells, the latter serving as control group. The average yield for 100 layings was 46 to 57 kg in the control group whereas in test groups, it ranged between 34 to 51 kg in the first test group and 22 to 38 kg in the rest. The difference in yield was $9{\sim}19$ kg depending on the season between control and test batches. In summer, this difference was higher, with high co-efficient of variation in test groups ($33{\sim}52$%). Further, water, soil and leaf samples were collected from selected rearers and were analyzed for zinc, copper, iron, lead and nickel. Results indicated significantly higher contents of these metals in samples from gardens using wastewater when compared control samples. Significantly (p<0.05 & p<0.01)) higher levels of zinc ($24{\sim}122$ ppm) and iron ($208{\sim}683$ ppm) were noticed in mulberry leaves during summer followed by winter and rainy season. The significance of high content of heavy metals in mulberry leaves and cocoon yield pattern of this area in relation to the quality of irrigation water is discussed.

• 한국ITS학회 논문지
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• 제14권4호
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• pp.18-26
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• 2015

본 연구에서는 새마을 무궁화 열차의 주요 5개노선(경부선, 호남선, 전라선, 장항선, 중앙선)의 단기수송수요의 예측모형 선정방안을 제시하고 유용성을 확인하기 위한 검증결과를 제시하였다. 분석을 위해 계절별 특성이 반영된 SARIMA 모형을 이용하였으며, 주중/주말 통행 특성 및 대체근무제 등과 같은 공휴일 특성을 반영하고자 각 노선별 주중/주말 일평균 모형을 각각 구축하였다. 또한 모형의 신뢰도를 높이기 위해 EXPO 개최, 새로운 노선의 개통 등 노선별 개입요소를 고려하여 수송수요의 예측모형에 반영하였으며 모형 예측력의 검증을 통해 정도 높은 모형을 구축하였음을 확인하였다. 본 연구를 통해 개발된 모형은 열차 노선별 단기운행계획 수립을 위한 기초자료로 활용될 수 있을 것으로 기대된다.