• Title/Summary/Keyword: dominant period

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Functional Characteristics and Diversity of a Novel Lignocelluloses Degrading Composite Microbial System with High Xylanase Activity

  • Guo, Peng;Zhu, Wanbin;Wang, Hui;Lu, Yucai;Wang, Xiaofen;Zheng, Dan;Cui, Zongjun
    • Journal of Microbiology and Biotechnology
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    • v.20 no.2
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    • pp.254-264
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    • 2010
  • To obtain an efficient natural lignocellulolytic complex enzyme, we screened an efficient lignocellulose-degrading composite microbial system (XDC-2) from composted agricultural and animal wastes amended soil following a long-term directed acclimation. Not only could the XDC-2 degrade natural lignocelluloses, but it could also secrete extracellular xylanase efficiently in liquid culture under static conditions at room temperature. The XDC-2 degraded rice straw by 60.3% after fermentation for 15 days. Hemicelluloses were decomposed effectively, whereas the extracellular xylanase activity was dominant with an activity of 8.357 U/ml on day 6 of the fermentation period. The extracellular crude enzyme noticeably hydrolyzed natural lignocelluloses. The optimum temperature and pH for the xylanase activity were $40^{\circ}C$ and 6.0. However, the xylanase was activated in a wide pH range of 3.0-10.0, and retained more than 80% of its activity at $25-35^{\circ}C$ and pH 5.0-8.0 after three days of incubation in liquid culture under static conditions. PCR-DGGE analysis of successive subcultures indicated that the XDC-2 was structurally stable over long-term restricted and directed cultivation. Analysis of the 168 rRNA gene clone library showed that the XDC-2 was mainly composed of mesophilic bacteria related to the genera Clostridium, Bacteroides, Alcaligenes, Pseudomonas, etc. Our results offer a new approach to exploring efficient lignocellulolytic enzymes by constructing a high-performance composite microbial system with synergistic complex enzymes.

Spatial Abundance and Diversity of Bacterioplankton in a Typical Stream-Forming Ecosystem, Huangqian Reservoir, China

  • Wei, Guangshan;Li, Jing;Wang, Ningxin;Gao, Zheng
    • Journal of Microbiology and Biotechnology
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    • v.24 no.10
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    • pp.1308-1318
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    • 2014
  • The specific freshwater environment of reservoirs formed by streams has not been well studied. In this paper, the bacterioplankton community in such a reservoir, the Huangqian Reservoir in eastern China, was described using culture-independent molecular methods. We found that the most dominant bacterioplankton were affiliated with Cyanobacteria, followed by Betaproteobacteria, Bacteroidetes, Gammaproteobacteria, and Actinobacteria. Both bacterial abundance and diversity increased along the direction of water flow, and the 16S rRNA gene copy number in the water outlet was nearly an order of magnitude higher than that in the water inlet. Pearson correlation analyses indicated that nitrate had a significantly negative correlation with the bacterial abundance (p < 0.05) and that ammonium was positively correlated with bacterial abundance (p < 0.05). Interestingly, owing to a remarkably negative correlation (p < 0.01), the ratio of nitrate and ammonium might serve as a good pre dictor of the relative abundance of bacterioplankton. According to redundancy analysis, nitrate and dissolved oxygen were the major factors influencing the bacterial communities. In addition, we attempted to determine the reasons why such a reservoir could maintain good ecological balance for a period of decades, and we found that the environmental factors and bacterial communities both played critical roles. This research will benefit our understanding of bacterial communities and their surrounding environments in freshwater ecosystems.

Examining on the Relationship Between Interdisciplinarity and Research Impact with Analyzing the Journals of Library and Information Science Field (학제성과 연구 영향력의 상관관계에 관한 연구: 문헌정보학 분야 학술지를 대상으로)

  • Park, SoYoon;Chung, EunKyung
    • Journal of the Korean Society for information Management
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    • v.30 no.4
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    • pp.7-29
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    • 2013
  • As interdisciplinary research has been dominant in various fields, the purpose of this study is to analyze the relationship between interdisciplinarity and research impact in the field of Library and Information Science. For a data set, ten journals ranked as the top of 2011 JCR's in terms of JIF (Journal Impact Factor) were selected. The citation data of 1,873 articles from the ten journals were collected from the WoS during the period from 2006 to 2010. In order to achieve the purpose of this study, as network analysis was conducted to investigate the interdisciplinarity of LIS field, interdisciplinarity indicators, and research impact factors were statistically analyzed. The findings of this study confirmed the interdisciplinary knowledge structure of the LIS field as previous studies identified. More importantly, this study demonstrated that a positive correlation existed between interdisciplinarity represented as betweenness centrality and research impact.

Study on the current status of naturalized plants in South Korea (한국내 귀화식물의 현황과 고찰)

  • Lee, You-Mi;Park, Soo-Hyun;Jung, Su-Young;Oh, Seung-Hwan;Yang, Jong-Cheol
    • Korean Journal of Plant Taxonomy
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    • v.41 no.1
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    • pp.87-101
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    • 2011
  • Naturalized plants were identified and recorded in South Korea based on field surveys and related literatures. These plants consisted of 321 taxa in total, belonging to 40 families, 175 genera, 302 species, 15 varieties and 4 forms. Among the plants the family Compositae was dominant containing 68 taxa (21.2% of the total population) and Poaceae with 62 taxa (19.3%) successively. Most of the plants were herbs and only 7 taxa trees. 221 taxa (68.8%) appeared to have invaded the country during the third period (1964-2010). 41.8% (134 taxa) of the total population were originated from Europe. These invasive plants were assessed with the degree of naturalisation which was categorized as I-V types.

Sexuality Expressed in the 19C Fashion in Foucauldian Post-Structural Perspective - Focusing on Femininity and Masculinity Represented in the Mainstream Fashion and Anti-Fashion in the Middle and Latter of the Nineteenth Century - (Foucault의 후기구조주의적 시각에서 본 19세기 패션에 표현된 성 - 19세기 중.후반 남녀 주류 패션과 반패션에 나타난 여성성과 남성성을 중심으로 -)

  • Choi, Kyung-Hee
    • The Research Journal of the Costume Culture
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    • v.15 no.2 s.67
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    • pp.232-251
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    • 2007
  • The purpose of this study was to understand sexuality expressed in fashion in a discursive view and reinterpret sexuality represented in fashion in the 19th century in Foucauldian post-structural perspective. As for methodology, at first the conception of sexuality was examined from structural feminism to post-structural pluralism by a literature review and discussed in relation with the matters of body and fashion on the basis of Foucault's discourse. Then, sexuality represented in the 19C fashion as a case study was re-estimated in terms of power relationship between dominant and oppositional discourses and mainstream fashion and anti-fashion as well. The conception of sexuality in Foucauldian post-structuralism maintains the view of plural sexuality, which floats by discourse and power produced in a specific historical context. In the Foucauldian perspective sexuality expressed in the mainstream fashion and anti-fashion in the nineteenth century shows the following aspects. The mainstream fashion in the middle and latter of the 19C made the clear sexual difference in dress of plain and functional male suit and extravagant and decorative female dress on the center of bourgeois masculinity in the context of modernity and capitalism. Although anti-fashion was also co-existed with the mainstream fashion, it was criticized by the Victorian people. It codifies sexual ideology of the binary opposition of male domination and female subordination. Therefore, the traditional sexual ideology in the 19C is a capitalist value, which gives a priority to bourgeois man's profits, and the Victorian discourses of sexuality constructs the clear sexual difference in dress in the period.

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A Study on the Characteristics of Ambient Suspended Particulate Matter at Coastal Area, Kangwha (해안지역 대기부유미립자상 물질의 특성에 관한 연구)

  • 강공언;우상윤;강병욱;김희강
    • Journal of Environmental Health Sciences
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    • v.20 no.4
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    • pp.1-9
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    • 1994
  • In order to investigate the regional level of air pollutants at Kangwha island situated on the western coast in Korea, the suspended particulate matter samples were collected by using the low volume air sampler on ten interval from March 1992 to February 1993 and the mass concentration of suspended particulate matter (SPM) and the chemical composition of water-soluble major ionic components in SPM samples were measured. During the sampling period, the average concentration of SPM under diameter 10 $\mu$m was found to be 48 $\mu$g/m$^3$ (+ 12). The seasonal concentration of SPM was showed in order of spring>fall>winter>summer. It was considered that higher concentration on spring than other season was affected by the long-range transport of Yellow sand particulate from China continent and lower concentration on summer by the washout and rainout effect of large rainfall. The content of water-soluble component in SPM samples was founded to be about 31% (14.69 $\mu$g/m$^3$) and 65% was unknown or unanalyzed. The content of cationic component showed in order of NH$_4^+$ (44.6%)>Na$^+$ (21.2%)>K$^+$ (14.7%)>Ca$^{2+}$ (13.6%)>Mg$^{2+}$ (5.9 %) and the content of anionic component SO$_4^{2-}$ (62.5%)>NO$_3^-$ (22.3%)>Cl$^-$ (15.2%), respectively. This fact indicates that ammonium and sulfate ion of water-soluble component in SPM sample were dominant in this region. From the chemical composition of water-soluble component, the most of Na$^+$, Mg$^{2+}$ and Cl$^-$ were originated from seawater source but K$^+$, Ca$^{2+}$ and SO$_4^{2-}$ were originated from other non-marine source. The contribution of seasalt to the composition of precipitation was 23%.

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Structure and Characteristics of Bacterial Community on Biofilm of Food Wastewater Treatment System in Winter (식품폐수 처리 공정용 생물막의 겨울철 세균군집 구조와 특성)

  • Lee, Dong-Geun;Yoo, Ki-Hwan;Park, Seong-Joo
    • Journal of Environmental Health Sciences
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    • v.37 no.2
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    • pp.124-132
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    • 2011
  • Biofilm and aeration tank of pilot and full RABC (rotating activated Bacillus contactor) plant were analyzed to characterize and determine bacterial community structure in food wastewater treatment system at winter. Concentration of heterotrophic bacteria and Bacillus group was $10^7$ and $10^5$ CFU/ml, respectively, at biofilm of pilot-plant while others represented $10^6$ and $10^4$ CFU/ml, respectively. Five and eight phyla were detected at biofilm of pilot- and full-plant, respectively, by 16S rDNA sequencing. Biofilm of pilot-plant was dominated by ${\beta}$-Proteobacteria (38.8%), ${\gamma}$-Proteobacteria (22.4%), and Bacteroidetes (12.2%), and the most dominant genus was Zoogloeae genus (22.4%). Candidate division TM7 (12.5%) was only detected at biofilm of full-plant and it was dominated by Bacteroidetes (33.3%), ${\gamma}$-Proteobacteria (29.2%), and ${\beta}$-Proteobacteria (20.8%). Clostridium genus specific primer set enabled to detect the sequences of Clostridium genus. These suggested that anaerobic and aerobic bacteria were coexisted even from the initial period of biofilm formation and ${\beta}$-Proteobacteria, ${\gamma}$-Proteobacteria and Bacteroidetes were major phyla in biofilm of food wastewater treatment system at winter.

The 40~50Day Intraseasonal Oscillation of the Geostationary Meteorological Satellite High Cloud Amount (GMS 상층운량의 40~50일 계절만 진동)

  • 하경자;서애숙
    • Journal of Environmental Science International
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    • v.5 no.5
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    • pp.619-633
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    • 1996
  • Intraseasonal variability of the tropical convection over the Indian/western Pacific is studied using the Geostationary Meteorological Satellite high cloud amount. This study is directed to find the tropical-extratropical interaction in the frequency range of intraseasonal and interannual variabilities of the summer monsoon occured over the domain of 90E-171W and 495-50N. Especially, in order to investigate the intraseasonal interaction of last Asia summer monsoon associated with the tropical convections in the high cloud amounts, the spatial and time structure of the intraseasonal oscillation for the movement-and the evolution of the large-scale connections are studied. To describe the spatial and the time evolution, the extended empirical orthogonal function analysis is applied. The first mode may be considered to a normal structure, indicating that the strong convection band over 90E-120E is extended to sastward but this mode was detected as the intraseasonal variability during summer monsoon. It is found that the dominant intraseasonal mode of the tropical convection consists of the spatial changes over a broad period range centered around 40~50days.

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Fluctuations of Pelagic Fish Populations in Relation to the Climate Shifts in the Far-East Regions

  • Gong, Yeong;Jeong, Hee-Dong;Suh, Young-Sang;Park, Jong-Hwa;Seong, Ki-Tack;Kim, Sang-Woo;Choi, Kwang-Ho;Han, In-Seong
    • Journal of Ecology and Environment
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    • v.30 no.1
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    • pp.23-38
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    • 2007
  • Based on a time series of ocean climate indices and catch records for seven pelagic fish species in the Tsushima Warm Current (TWC) and Kuroshio-Oyashio Current (KOC) regions from 1910 to 2004, we detected regional synchrony in the long-term fluctuations of the fish populations and identified alternation patterns of dominant species related to climate shifts. The annual catches of Pacific herring, Japanese sardines, Japanese anchovies, jack mackerel, chub mackerel, Pacific saury and common squid in the TWC region fluctuated in phase with those in the KOC region, which suggests that they were controlled by the same basin-wide climate forcing. After the collapse of the herring fishery, the alternation sequence was: sardines (1930s), Pacific saury, jack mackerel, common squid and anchovies ($1950s{\sim}1960s$), herring ($late\;1960s{\sim}early\;1970s$), chub mackerel (1970s) and then sardines (1980s). As sardine biomass decreased in the late stages of the cool regime, catch of the other four species increased immediately during the warm period of the 1990s. Regional differences in the amplitude of long-term catch fluctuations for the seven pelagic fishes could be explained by regional differences in availability, fishing techniques and activity.

Seasonal Variations of Water Quality and Phytoplankton of 4 Lagoons in the East Coast of Korea (동해안 4개 석호의 수질과 식물플랑크톤 계절별 변화에 관한 연구)

  • Moon, Byeong Ryeol;Jeon, Hyeon-Jin;Jeon, Sook Lye;Lee, Jae Sun;Shin, Ji Eun;Ahn, Ji Hye;Yang, Yong Woon;Hyun, Moon Sik;Kim, Mia
    • Journal of Environmental Science International
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    • v.24 no.9
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    • pp.1101-1121
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    • 2015
  • The seasonal variation of phytoplankton communities and its standing crops in accordance with environmental factors were investigated at Yeongrang-ho, Cheongcho-ho, Mae-ho and Hyang-ho which are located in the East coast of Korea during April to October 2011. High concentrations of T-N and T-P were observed in four lagoons due to the inflowing nutrients from farmlands and residential areas near lagoons. Nutrient salts mainly composed of nitrogen and phosphate caused the eutrophication of the lakes, leading to the robust growth of phytoplankton. During the period of investigation, 64 to 107 taxa of phytoplankton were observed in four lagoons. Diatoms were the most dominant species with high density. Non-point pollution source was estimated as the main cause of water pollution of lagoons. Trophic states of lagoons evaluated using the value of TSI and TSIKO indicated that all the investigated lagoons were in the eutrophication state.