• 제목/요약/키워드: Mixed methods research

검색결과 1,022건 처리시간 0.027초

화력발전소의 혼합연료 사용에 따른 중금속 배출량 변화 연구 (A Study on the Changes in Heavy Metal Emissions when Using Mixed Fuel in a Thermal Power Plant)

  • 송영호;김옥;박상현;이진헌
    • 한국환경보건학회지
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    • 제44권1호
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    • pp.63-75
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    • 2018
  • Objectives: The aim of this research is to explore the total heavy metals from a coal-fired power plant burning bituminous coal with wood pellets due to the implementation of the Renewable Portfolio Standard policy (RPS, 10% of electricity from renewable energy resources by 2023). Methods: The research was carried out by collecting archival data and using the USEPA's AP-42 & EMEP/EEA compilation of emission factors for use in calculating emissions. The Monte Carlo method was also applied for carrying out the calculations of measurement uncertainty. Results: In this paper, the results are listed as follows. Sb was measured at 110 kg (2015) and calculated as 165 kg (2019) and 201 kg (2023). Cr was measured at 1,597 kg (2015) and calculated as 1,687 kg (2019) and 1,728 kg (2023). Cu was measured at 2,888 kg (2015) and calculated as 3,133 kg (2019) and 3,264 kg (2023). Pb was measured at 2,580 kg (2015) and calculated as 2,831 kg (2019) and 2,969 kg (2023). Mn was measured at 3,011 kg (2015) and calculated as 15,034 kg (2019) and 23,014 kg (2023). Hg was measured at 510 kg (2015) and calculated as 513 kg (2019) and 537 kg (2023). Ni was measured at 1,720 kg (2015) and calculated as 1,895 kg (2019) and 1,991 kg (2023). Zn was measured at 7,054 kg (2015) and calculated as 9,938 kg (2019) and 11,778 kg (2023). Se was measured at 7,988 kg (2015) and calculated as 7,663 kg (2019) and 7,351 kg (2023). Conclusion: This shows that most heavy metals would increase steadily from 2015 to 2023. However, Se would decrease by 7.9%. This analysis was conducted with EMEP/EEA's emission factors due to the limited emission factors in South Korea. Co-firewood pellets in coal-fired power plants cause the emission of heavy metals. For this reason, emission factors at air pollution control facilities would be presented and the replacement of wood pellets would be needed.

Improvement of PCR Amplification Bias for Community Structure Analysis of Soil Bacteria by Denaturing Gradient Gel Electrophoresis

  • Ahn, Jae-Hyung;Kim, Min-Cheol;Shin, Hye-Chul;Choi, Min-Kyeong;Yoon, Sang-Seek;Kim, Tae-Sung;Song, Hong-Gyu;Lee, Geon-Hyoung;Ka, Jong-Ok
    • Journal of Microbiology and Biotechnology
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    • 제16권10호
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    • pp.1561-1569
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    • 2006
  • Denaturing gradient gel electrophoresis (DGGE) is one of the most frequently used methods for analysis of soil microbial community structure. Unbiased PCR amplification of target DNA templates is crucial for efficient detection of multiple microbial populations mixed in soil. In this study, DGGE profiles were compared using different pairs of primers targeting different hypervariable regions of thirteen representative soil bacteria and clones. The primer set (1070f-1392r) for the E. coli numbering 1,071-1,391 region could not resolve all the 16S rDNA fragments of the representative bacteria and clones, and moreover, yielded spurious bands in DGGE profiles. For the E. coli numbering 353-514 region, various forward primers were designed to investigate the efficiency of PCR amplification. A degenerate forward primer (F357IW) often yielded multiple bands for a certain single 16S rDNA fragment in DGGE analysis, whereas nondegenerate primers (338f, F338T2, F338I2) differentially amplified each of the fragments in the mixture according to the position and the number of primer-template mismatches. A forward primer (F352T) designed to have one internal mismatch commonly with all the thirteen 16S rDNA fragments efficiently produced and separated all the target DNA bands with similar intensities in the DGGE profiles. This primer set F352T-519r consistently yielded the best DGGE banding profiles when tested with various soil samples. Touchdown PCR intensified the uneven amplification, and lowering the annealing temperature had no significant effect on the DGGE profiles. These results showed that PCR amplification bias could be much improved by properly designing primers for use in fingerprinting soil bacterial communities with the DGGE technique.

Essential oils as growth-promoting additives on performance, nutrient digestibility, cecal microbes, and serum metabolites of broiler chickens: a meta-analysis

  • Irawan, Agung;Hidayat, Cecep;Jayanegara, Anuraga;Ratriyanto, Adi
    • Animal Bioscience
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    • 제34권9호
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    • pp.1499-1513
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    • 2021
  • Objective: The purpose of this meta-analysis was to evaluate the effect of dietary essential oils (EOs) on productive performance, nutrient digestibility, and serum metabolite profiles of broiler chickens and to compare their effectiveness as growth-promoting additives against antibiotics. Methods: Peer-reviewed articles were retrieved from Web of Science, Science Direct, PubMed, and Google scholar and selected based on pre-determined criteria. A total of 41 articles containing 55 experiments with 163 treatment units were eligible for analyses. Data were subjected to a meta-analysis based on mixed model methodology considering the doses of EOs as fixed effects and the different studies as random effects. Results: Results showed a linear increase (p<0.001) on body weight gain (BWG) where Antibiotics (FCR) and average daily feed intake decreased (p<0.001) linearly with an increasing dose of EOs. Positive effects were observed on the increased (p<0.01) digestibility of dry matter, crude protein, ether extract, and cecal Lactobacillus while Escherichia coli (E. coli) population in the cecum decreased (p<0.001) linearly. There was a quadratic effect on the weight of gizzard (p<0.01), spleen (p<0.05), bursa of fabricius (p<0.001), and liver (p<0.10) while carcass, abdominal fat, and pancreas increased (p<0.01) linearly. The dose of EOs linearly increased high density lipoprotein, glucose, protein, and globulin concentrations (p<0.01). In comparison to control and antibiotics, all type of EOs significantly reduced (p<0.001) FCR and tended to increase (p<0.1) BWG and final body weight. Cinnamaldehyde-compound was the only EOs type showing a tendency to increase (p<0.1) carcass weight, albumin, and protein of serum metabolites while this EOs together with EOs-Blend 1 decreased (p<0.01) E. coli population. Low density lipoprotein concentration decreased (p<0.05) with antibiotics and carvacrol-based compound when compared to the control group. Conclusion: This evidence confirms that EOs are suitable to be used as growth promoters and their economical benefit appears to be promising.

3차원 포인트 클라우드 모델링 기법을 활용한 바이오폴리머 기반 제방 보강공법의 성능 평가 (Application of 3D point cloud modeling for performance analysis of reinforced levee with biopolymer)

  • 고동우;강준구;강우철
    • 한국수자원학회논문집
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    • 제54권3호
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    • pp.181-190
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    • 2021
  • 본 연구에서는 하천에서의 월류 발생에 따른 제방의 붕괴를 방지하거나 피해를 최소화하기 위한 신소재 보강공법을 제체 표면에 적용하여 그 효과를 검증하기 위한 실규모 횡월류 붕괴 실험을 수행하였다. 본 실험을 위해 제방 모형은 높이 2.5 m, 길이 12 m, 사면경사 1:2로 구성하였다. 또한 제방의 경우 습식 공법을 이용하여 바이오폴리머 분말, 물, 화강풍화토, 황토를 적정 비율로 혼합한 신소재를 제체 표면에 약 5 cm 두께로 분사한 뒤 식생활착 모니터링을 거쳐 최종 실험모형을 완성하였다. 안동하천연구센터 A3 수로 상류에서 4 ㎥/s 의 유량을 유입시켜 횡월류 흐름을 유도하였으며, 음향 도플러 유속계를 이용하여 상·하류의 유량 및 횡월류량의 변동을 측정하였다. 또한, 제방보강공법의 성능을 평가하기 위해 이미지 픽셀 기법 및 3차원 포인트 클라우드 모델링 기법을 활용한 시간에 따른 제방의 표면손실률을 산정함으로써 영상분석 기반의 새로운 평가 도구를 제시하였다. 본 연구결과를 적절하게 활용하게 되면 제방보강공법의 성능을 평가하는데 기초 자료로 활용될 수 있을 것으로 사료된다.

한국형 총식이조사에 근거한 우리 국민의 식품 기인 요오드 섭취량 추정 (Estimation of Dietary Iodine Intake of Koreans through a Total Diet Study (TDS))

  • 이지연;여윤재;서민정;이계호;김초일
    • 대한지역사회영양학회지
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    • 제26권1호
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    • pp.48-55
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    • 2021
  • Objectives: This study was conducted to estimate the dietary iodine intake of Koreans by a Total Diet Study (TDS) which provides 'closer-to-real' estimates of exposure to hazardous materials and nutrients through an analysis of table-ready (cooked) samples of foods. Methods: Dietary intake data from 2013-2017 Korea National Health and Nutrition Examination Survey (KNHANES) was used to select representative foods (RFs) for iodine analysis. A total of 115 RFs were selected and 158 'RF × cooking method-combination' pairs were derived by pairing each RF to corresponding cooking method(s) used more frequently. RFs were collected from 9 mega-markets in 9 metropolitan cities nationwide and mixed into composites prior to cooking preparation to a 'table ready' state for iodine analysis by inductively coupled plasma mass spectrometry. Iodine intake of Koreans was estimated based on the food intake data of the 2016-2018 KNHANES. Results: High iodine content was detected in seaweeds such as sea mustard and kelp. The mean iodine intake/capita/day was 418.4 ㎍ and the median value was 129.0 ㎍. Seaweeds contributed to 77.4% of the total iodine intake and the contribution by food item was as follows: sea mustard (44.0%), kelp (20.4%), laver (13.1%), milk (3.9%), egg (3.5%). Compared to the Dietary Reference Intakes for Koreans 2020, the proportion of people with iodine intake exceeding the tolerable upper intake level or below the estimated average requirement was high in the physiologically vulnerable groups (infants, children, pregnant women, and lactating women). Conclusions: The results, drawn from a TDS, are regarded closer to real estimates for iodine intake of Koreans compared with values in existing literature, which were based on a very limited variety of foods. On the other hand, it seems necessary to seek out solutions for the problematic iodine intake among physiologically vulnerable groups through in-depth analyses on food intake data collected with significant scale & quality.

염소의 피하농양 발생에 따른 혈액 내 염증지표 분석 (Analysis of inflammatory markers in blood related with the occurrence of subcutaneous abscesses in goats)

  • 구지영;박준환;김선호;조용일;김찬란;차승언;신기욱;박진호
    • 한국동물위생학회지
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    • 제45권1호
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    • pp.47-54
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    • 2022
  • Subcutaneous abscesses, which occur mainly in goats and sheep, are lymph node abscesses caused by Corynebacterium pseudotuberculosis infection, and are divided into internal, external, and mixed types depending on the type of occurrence. While diagnostic methods for subcutaneous abscesses have been continuously studied, research reports for effective treatment and management of subcutaneous abscesses are inadequate. Therefore, this study was conducted to determine the changes in biometric information related to the inflammatory markers of goats induced by subcutaneous abscesses by infection with C. pseudotuberculosis. For this, hematological tests, analysis of inflammatory indicators, and analysis of serum proteins through electrophoresis separation of goats with healthy goats and goats inoculated with C. pseudotuberculosis to induce subcutaneous abscesses were compared and analyzed by date, and the differences and characteristics were identified periodically. As a result, in goats induced with subcutaneous abscesses, anemia findings related to a rapid decrease in red blood cell (RBC), hematocrit (HCT), and hemoglobin (Hb) were observed, and a significant increase in inflammatory cells expressed in total white blood cell (WBC), neutrophil, and monocytes was observed. And the levels of acute phase protein (APP) such as fibrinogen, haptoglobin, and serum amyloid A (SAA) were observed to increase rapidly immediately after infection. In addition, in the results of electrophoretic analysis of serum proteins, it was observed that the levels of α-globulin and β-globulin were significantly increased in goats with subcutaneous abscesses. That is, when looking at these changes, it was found that the systemic inflammatory response of goats was rapidly induced immediately after infection with the C. pseudotuberculosis pathogen. Through this study, it was possible to identify changes in the biomarkers of goats with subcutaneous abscesses, which had not been reported. Furthermore, these analyzed data are thoughts to be of great help in identifying, treating, and managing the goats of subcutaneous abscesses.

고속철도역 신설과 도시 재구조화 연계 계획의 특성 - JR큐슈 주요 역을 중심으로 (A Study on the Characteristics of Urban Re-Organization regarding as an Establishment of New High-Speed Railway Stations focused on JR Kyushu's Main Stations)

  • 신예경;정혜진
    • 예술인문사회 융합 멀티미디어 논문지
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    • 제6권7호
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    • pp.427-437
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    • 2016
  • 본 연구는 일본의 큐슈지역에서 고속철도가 추가로 부설되면서, 기존의 구 철도역사에 이를 수용하기 위한 기능을 도입하기 위해 새로운 고속철도역사를 추가로 건립하고, 건립과 동시에 철도역사를 중심으로 한 인접역세권 개발을 추진하고 있는 사례들에 주목한 연구이다. 일본 큐슈 지역의 고속철도역사를 중심으로 한 구도시의 재구조화 방식 및 기법 및 특성을 분석하여 그 계획적 의미 및 특성을 도출하고, 국내 역세권 개발에 적용 가능한 도시계획기법을 연구하는데 그 목적이 있다. 연구대상은 일본 큐슈 지역에 신칸센이 연장되면서 최근 5년 이내 신축되었거나, 개발 중인 하카타역, 구마모토역, 가고시마 중앙역의 3개 역사를 사례로 하였다. 연구의 결과 큐슈 북부, 중부, 남부에 위치한 각 해당 철도역은 큐슈 전 지역 내에서 각 역의 지리적 위치에 의한 지역적 관계, 즉 지리적 입지와 철도네트워크 내에서의 각 역 기능의 적극적 연계, 도심과 역과의 관계 재설정, 관광지 개발과 밀접한 연계체계 확립, 낙후될 수밖에 없었던 선로 반대측으로의 개발을 확장시키는 고속철도역사 병설방식, 고밀 복합용도 개발을 통한 상주인구 확보 등과 같은 전략을 통해 역을 중심으로 지역계획과 통합하여 도심재생을 추진하였음을 확인하였다.

기계학습법을 이용한 동해 울릉분지의 봄과 여름 순군집생산 추정 (Estimation of the Spring and Summer Net Community Production in the Ulleung Basin using Machine Learning Methods)

  • 함도식;이인희;추민기
    • 한국해양학회지:바다
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    • 제29권1호
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    • pp.1-13
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    • 2024
  • 동해 남서부해역은 대마난류나 연안 용승에 의한 영양염 공급 등으로 동해 북부나 동부에 비해 일차생산력이 높은 것으로 알려져 있지만, 이 해역의 생물 펌프에 관한 연구는 제한적이다. 본 연구에서는 O2/Ar 측정으로 산출한 고해상도 순군집생산 현장 관측 결과와 기계학습 모형을 결합하여 시공간 해상도가 8일 간격, 4 km인 봄과 여름 순군집생산 시계열 자료를 추정하였다. 기계 모형의 예측과 실측의 평균 제곱근 오차는 6 mmol O2 m-2 d-1로 관측값 평균의 15%에 해당했다. 울릉분지 중앙부의 순군집생산은 3월에 49 mmol O2 m-2 d-1로 가장 높았고, 6월과 7월에 18 mmol O2 m-2 d-1로 가장 낮았다. 이 같은 계절 변화는 3He 기체교환율로 추정한 질산염 공급률이나 234Th 비평형법으로 추정한 입자유기탄소 방출률과 유사하였다. 봄과 여름의 순군집생산 추정으로 한정된 이 연구방법을 가을과 겨울로 확대하기 위해서는 아표층수의 표층 혼입에 따른 O2/Ar 순군집생산의 오차를 보정하는 연구가 필요하다.

Mortality Burden Due to Short-term Exposure to Fine Particulate Matter in Korea

  • Jongmin Oh;Youn-Hee Lim;Changwoo Han;Dong-Wook Lee;Jisun Myung;Yun-Chul Hong;Soontae Kim;Hyun-Joo Bae
    • Journal of Preventive Medicine and Public Health
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    • 제57권2호
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    • pp.185-196
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    • 2024
  • Objectives: Excess mortality associated with long-term exposure to fine particulate matter (PM2.5) has been documented. However, research on the disease burden following short-term exposure is scarce. We investigated the cause-specific mortality burden of short-term exposure to PM2.5 by considering the potential non-linear concentration-response relationship in Korea. Methods: Daily cause-specific mortality rates and PM2.5 exposure levels from 2010 to 2019 were collected for 8 Korean cities and 9 provinces. A generalized additive mixed model was employed to estimate the non-linear relationship between PM2.5 exposure and cause-specific mortality levels. We assumed no detrimental health effects of PM2.5 concentrations below 15 ㎍/m3. Overall deaths attributable to short-term PM2.5 exposure were estimated by summing the daily numbers of excess deaths associated with ambient PM2.5 exposure. Results: Of the 2 749 704 recorded deaths, 2 453 686 (89.2%) were non-accidental, 591 267 (21.5%) were cardiovascular, and 141 066 (5.1%) were respiratory in nature. A non-linear relationship was observed between all-cause mortality and exposure to PM2.5 at lag0, whereas linear associations were evident for cause-specific mortalities. Overall, 10 814 all-cause, 7855 non-accidental, 1642 cardiovascular, and 708 respiratory deaths were attributed to short-term exposure to PM2.5. The estimated number of all-cause excess deaths due to short-term PM2.5 exposure in 2019 was 1039 (95% confidence interval, 604 to 1472). Conclusions: Our findings indicate an association between short-term PM2.5 exposure and various mortality rates (all-cause, non-accidental, cardiovascular, and respiratory) in Korea over the period from 2010 to 2019. Consequently, action plans should be developed to reduce deaths attributable to short-term exposure to PM2.5.

토양 방선균 Streptomyces scopuliridis KR-001 균주 배양액의 살초활성을 증가시키는 Adjuvant 탐색 (The Influence of Adjuvants on Herbicide Activity of Streptomyces scopuliridis KR-001)

  • 김재덕;신훈탁;김영숙;고영관;조남규;황기환;구석진;최정섭;박기웅
    • Weed & Turfgrass Science
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    • 제4권4호
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    • pp.288-294
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    • 2015
  • 본 연구는 토양방선균 Streptomyces scopuliridis KR-001 대사물질의 살초활성을 증가시키는 adjuvant를 선발하기 위해 수행되었다. 작물보호제에서 보편적으로 사용하는 21종의 adjuvant를 8종(화본과잡초 6종, 광엽잡초 2종)의 피검식물에 처리하여 살초활성이 상대적으로 증가된 LE7[Polyoxyethylene lauryl ether]과 EP4C [Sodium bis (2-ethylhexyl) sulfosuccinate]를 선발하였다. 선발된 2종의 adjuvant를 KR-001 대사물질과 함께 8종(화본과잡초 4종, 광엽잡초 4종)의 피검식물을 대상으로 살포한 결과 $2,000L\;ha^{-1}(65{\mu}g\;a.i.\;ml^{-1})$ 처리가 $1,000L\;ha^{-1}(130{\mu}g\;a.i.\;ml^{-1})$ 처리보다 살초활성이 더 높게 나타났다. 또한 6종(화본과 잡초 3종, 광엽잡초 3종)의 피검식물에 대하여 포장 실증평가를 수행한 결과 $1,300{\mu}g\;ml^{-1}$의 KR-001 대사물질에 $2{\mu}g\;ml^{-1}$ 농도로 EP4C를 첨가하여 $2,000L\;ha^{-1}$ 처리량으로 살포시 대조약제인 glufosinate-ammonium ($540g\;a.i.\;ha^{-1}$)과 대등한 약효를 보였다. 향후 선발된 2종의 adjuvant를 대상으로 복합 및 다중처리와 잡초의 생육 정도에 따른 처리시기 조절 등으로 보다 효과적인 약효증진 기술을 개발하고자 한다.