• 제목/요약/키워드: environmental studies

검색결과 9,833건 처리시간 0.038초

Population Dynamics of Phage-Host System of Microlunatus phosphovorus Indigenous in Activated Sludge

  • Lee, Sang-Hyon;Otawa, Kenichi;Onuki, Motoharu;Satoh, Hiroyasu;Mino, Takashi
    • Journal of Microbiology and Biotechnology
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    • 제17권10호
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    • pp.1704-1707
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    • 2007
  • Monitoring of the phage-host system of Microlunatus phosphovorus indigenous in activated sludge was attempted. A laboratory-scale activated sludge process was operated for 5 weeks with synthetic wastewater. The phage-host system population in the process was monitored by plaque assay and FISH methods at every 3 days. During the process operation, the phage-host system populations were more or less steady, except for 1 week in the middle of the operation. In that period, initially M. phosphovorus decreased significantly and its lytic bacteriophages increased, and then M. phosphovorus increased back to its original level while its lytic bacteriophages decreased. This observation suggests that lytic bacteriophages should be considered as one of the biological factors affecting the bacterial population dynamics in activated sludge processes.

Plant growth promoting rhizobacteria that decrease chromium toxicity in Brassica juncea

  • M. Rajkumar;Lee, Kui-Jae;Lee, Wang-Hyu;R. Nagendran
    • 한국자원식물학회:학술대회논문집
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    • 한국자원식물학회 2003년도 제10차 국제학술회의 및 추계정기 학술발표회
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    • pp.14-14
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    • 2003
  • The aim of the present study isto assess the importance of siderophore producing rhizosphere bacteria on the growth of Brassica junceaunder chromium stress. Pseudomonassp. (A4) produced an iron chelating substance siderophores in iron deficient medium. Under chromium stress condition Pseudomonassp. (A4) markedly increased the root and shoot length and also biomass of Brassica juncea as compared to Pseudomonas sp. (A3). This plant growth promotion has been related to the microbial production of siderophore.

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Growth of Phaseolus mungounder chromium stress - influence of chromate reducing bacteria

  • M. Rajkumar;Lee, Kui-Jae;Seo, Jae-Hwan;Lee, Wang-Hui
    • 한국자원식물학회:학술대회논문집
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    • 한국자원식물학회 2003년도 제10차 국제학술회의 및 추계정기 학술발표회
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    • pp.57-57
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    • 2003
  • The plant growth promoting rhizobacteria (PGPR), Pseudomonas sp. (A3) and Bacillus sp. (AT33) were isolated from the rhizosphere of Amaranthus blitum collected from soil contaminated with chromium. Bothbacterial strains quantitatively reduced hexavalent chromium to trivalent chromium. Pseudomonas sp. broughter greater conversion of Cr6+ in the medium (100%) as compared to Bacillus sp.(62%). Phaseolus mungo seeds inoculated with Pseudomonas sp. or Bacillus sp. were grown under different concentration of chromium. The monitoredparameters included elongation of shoot and root, fresh weight, dry weight and concentration of chromium in the shoot and root systems. As compared to non inoculated seedlings those inoculated with A3 and AT33 exhibited better growth.

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Effect of UV -B radiation on seedlings of two Solidago virgaurea populations from the Mt. Hakusan area of Japan

  • Nakajima, Nobuyoshi;Takahashi, Shinya;Tamaoki, Masanori;Kubo, Akihiro;Aono, Mitsuko;Saji, Hikaru
    • Journal of Photoscience
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    • 제9권2호
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    • pp.400-402
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    • 2002
  • We collected seeds of Solidago virgaurea plants growing at different altitudes on the Mt Hakusan area in Japan and cultivated them in a naturally-lit green house. Three-week-old seedlings were irradiated with supplemental UV-B for 12 h each day for 1 and 2 weeks. After a week of itradiation the seedlings of the population collected from the higher altitude at Oh-nanjiho (ON) had accumulated more anthocyanins than those from the lower altitude at Bettoh-deai (BD). Levels of anthocyanins in the ON seedlings were highly correlated with the dose of UV-B radiation and the correlation was also observed after 2 weeks. The growth of the third leaves was retarded by UV-B radiation in both populations. The extent of growth retardation in the third leaves was correlated with the dose of UV -B radiation in both populations. However, no significant difference in the extent of leaf area growth was observed between the ON and BD populations. The increase in plant fresh weight was extensively inhibited in the ON seedlings after 1 week of UV-B radiation. The inhibition was recovered to those in the BD population by 2 weeks irradiation. These results indicate that these populations respond differentially to supplementary UV -B radiation during the first week. Because flavonoids such as anthocyanins play an important role in protection against UV-B radiation in many plants, populations growing at higher altitude may be better able to adapt to increased global levels of UV-B radiation.

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환경성과와 재무성과 간의 관련성과 조절요인에 관한 메타분석 (CEP-CFP Relationship and Its Moderators : A Meta-analysis)

  • 육근효
    • 환경정책연구
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    • 제13권1호
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    • pp.25-47
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    • 2014
  • 여기에서는 CEP-CFP 간의 관련성 관련 연구들을 종합하고 체계적으로 분석해 보고 서로 다른 맥락에서 이루어진 연구들을 비교하여 조절변수를 찾아내기 위해 메타분석을 시도하였다. 연구결과를 보면 첫째, 다섯 가지 CEP척도는 모두 CFP척도와 양의 관련성을 보였으나 환경투자 척도는 유의하지 않았다. CFP척도는 모두 CEP와 정의 상관을 보여 주었다. 둘째, CEP-CFP 간의 관련성을 설명하는 조절변인을 확인하기 위한 메타분석의 결과는 측정방식과 분석(추정)모형은 CEP-CFP 간의 관계를 조절하였다. 반면에 출판년도, 시차변수의 포함 여부, 표본 크기, 학술지 종류는 조절변수로서의 역할을 수행하지 않았다.

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Ecological land cover classification of the Korean peninsula Ecological land cover classification of the Korean peninsula

  • Kim, Won-Joo;Lee, Seung-Gu;Kim, Sang-Wook;Park, Chong-Hwa
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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    • pp.679-681
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    • 2003
  • The objectives of this research are as follows. First, to investigate methods for a national-scale land cover map based on multi-temporal classification of MODIS data and multi-spectral classification of Landsat TM data. Second, to investigate methods to p roduce ecological zone maps of Korea based on vegetation, climate, and topographic characteristics. The results of this research can be summarized as follows. First, NDVI and EVI of MODIS can be used to ecological mapping of the country by using monthly phenological characteris tics. Second, it was found that EVI is better than NDVI in terms of atmospheric correction and vegetation mapping of dense forests of the country. Third, several ecological zones of the country can be identified from the VI maps, but exact labeling requires much field works, and sufficient field data and macro-environmental data of the country. Finally, relationship between land cover types and natural environmental factors such as temperature, precipitation, elevation, and slope could be identified.

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