• The Korean Journal of Ecology
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• v.24 no.4
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• pp.239-243
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• 2001

One of the most important justifications of conservation of ecosystem and biodiversity is that diversity begets stability. Impact of biodiversity on community and ecosystem function has long been debated in science. Here we report the stability analysis of soil oribatid mite communities from environmentally stressed habitat(Namsan) and relatively well preserved habitat (Kwangreung) with the perspective of consistency as a primary criteria of stability. Stability of oribatid mite communities were evaluated with turnover rate, constancy analysis, b diversity index, and absolute abundance, abundance ranking, and the presence or absence of species over time. Out of 6 criteria, three consented that oribatid community from Kwangreung was more stable than that from Namsan. Those are turnover rate in litter layer, constancy analysis, and absolute abundance. Feasibility of stability analysis using oribatid mites was further discussed, rendering further study.

• Journal of Environmental Impact Assessment
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• v.32 no.2
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• pp.61-71
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• 2023

As differences in the impact of each species on a spatial scale occur, analysis at the landscape scale is necessary to evaluate the impact of a development project. In previous studies, the Incidence Function Model (IFM) based on meta population theory was used to analyze the impact of species on the environment that changes according to urban development. However, since the model was required at least 10 occupied areas, it is difficult to use it for species that are difficult to monitor such as endangered species. Therefore, we proposed the Incidence Function Model (IFM) using species distribution model to fill the species data. In addition, we reviewed whether the developed model can be used in environmental impact assessment. As a result of the analysis, the minimum occupancy of Prionailurus bengalensis on urban development decreased to 56.5% and the possibility of survival to 28.7%. We confirmed that It rapidly decreased from the reference points of 230 and 70habitats through analysis of the meta-population capacity according to the decrease in the number of habitats. These results can be assessing the environment impact of each species on habitat loss. And it can support decision-making on the minimum number and area of habitat for species protection. This study is expected to be used as basic data for environment impact assessment on before and after development projects and mitigation measures plans, thereby increasing the effectiveness of reduction plans.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.7
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• pp.995-1002
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• 2008

Kura clover (Trifolium ambiguum M. Bieb.) is a rhizomatous perennial legume that has potential as a forage crop in the North-Central USA because of its excellent persistence under environmental extremes. Little information is available about defoliation effects on productivity of mixtures of kura clover with grasses typically grown in this region. Two field trials were conducted to evaluate the effects of defoliation management on yield and species composition of binary mixtures of 'Rhizo' kura clover with 'Comet' orchardgrass (Dactylis glomerata L.), 'Badger' smooth bromegrass (Bromus inermis Leyss.), 'Park' Kentucky bluegrass (Poa pratensis L.), and solo-seeded kura clover near Arlington, WI. Three harvest schedules (three, four, or five times annually) and two cutting heights (4 or 10 cm) were imposed. Infrequent defoliation and lower cutting height produced significantly greater total forage yield, 6.6, 5.8, and 5.2 Mg/ha in 3-, 4-, and 5-harvest systems, respectively; and 6.5 and 5.2 Mg/ha for the 4- and 10-cm cutting height, respectively. Averaged over 3 yr and two environments, mixtures had higher forage productions than solo kura clover (6.3, 5.7, and 6.0 Mg/ha for the Kentucky bluegrass, orchardgrass, and smooth bromegrass mixtures, respectively; compared to 5.2 Mg/ha for solo kura clover). The proportion of kura clover in mixtures increased from yr 1 to yr 2 and was constant from yr 2 to yr 3 (34, 58, and 57%, respectively). We conclude that kura clover has excellent potential as a long-term component of grass-legume mixtures regardless of the cutting height, harvest frequency or grass species, even though the proportion of kura clover in harvested forage was significantly greater with less frequent harvest and shorter cutting height of all mixtures.

• Membrane and Water Treatment
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• v.9 no.6
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• pp.405-419
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• 2018

Persulfates (i.e., peroxymonosulfate and peroxydisulfate) are capable of oxidizing a wide range of organic compounds via direct reactions, as well as by indirect reactions by the radical intermediates. In aqueous solution, persulfates undergo self-decomposition, which is accelerated by thermal, photochemical and metal-catalyzed methods, which usually involve the generation of various radical species. The chemistry of persulfates has been studied since the early twentieth century. However, its environmental application has recently gained attention, as persulfates show promise in in situ chemical oxidation (ISCO) for soil and groundwater remediation. Persulfates are known to have both reactivity and persistence in the subsurface, which can provide advantages over other oxidants inclined toward either of the two properties. Besides the ISCO applications, recent studies have shown that the persulfate oxidation also has the potential for wastewater treatment and disinfection. This article reviews the chemistry regarding the hydrolysis, photolysis and catalysis of persulfates and the reactions of persulfates with organic compounds in aqueous solution. This article is intended to provide insight into interpreting the behaviors of the contaminant oxidation by persulfates, as well as developing new persulfate-based oxidation technologies.

• BMB Reports
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• v.44 no.1
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• pp.1-10
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• 2011

Inter-cellular communication via diffusible small molecules is a defining character not only of multicellular forms of life but also of single-celled organisms. A large number of bacterial genes are regulated by the change of chemical milieu mediated by the local population density of its own species or others. The cell density-dependent "autoinducer" molecules regulate the expression of those genes involved in genetic competence, biofilm formation and persistence, virulence, sporulation, bioluminescence, antibiotic production, and many others. Recent innovations in recombinant DNA technology and micro-/nano-fluidics systems render the genetic circuitry responsible for cell-to-cell communication feasible to and malleable via synthetic biological approaches. Here we review the current understanding of the molecular biology of bacterial intercellular communication and the novel experimental protocols and platforms used to investigate this phenomenon. A particular emphasis is given to the genetic regulatory circuits that provide the standard building blocks which constitute the syntax of the biochemical communication network. Thus, this review gives focus to the engineering principles necessary for rewiring bacterial chemo-communication for various applications, ranging from population-level gene expression control to the study of host-pathogen interactions.

• Korean Journal of Veterinary Research
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• v.45 no.3
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• pp.359-367
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• 2005

This study was carried out to understand the contamination patterns of Listeria in pork processing plants. A total of 402 samples were collected from carcass, pork during processing, surfaces of equipment and environment, and 238 isolates of Listeria species were identified. L. innocua was found in 64.7% of the isolates, L. monocytogenes in 33.2%, and L. welshimeri in 2.1%. Random amplified polymorphic DNA (RAPD) analysis performed to investigate the origin and routes of Listeria contamination, showed 21 composite types of L. monocytogenes and 26 composite types of L. innocua. It was confirmed that Listeria contamination begins with contaminated incoming carcass and ever-present contaminants in the processing environments. The persistence and dissemination of the same strain of L. monocytogenes and L. innocua throughout the processing line revealed that the sanitation standard operating procedure should be implemented to minimize the risk of colonization in the workplace. Molecular subtyping of L. innocua allowed us to tracing the possibility of cross-contamination during processing.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.103-110
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• 2022

Ultrafine Particle number and size distributions were simultaneously measured at rural area around the power plant in Dangjin, South Korea. New Particle formation and growth events were frequently observed during January, 2021 and classified based on their strength and persistence as well as the variation in geometric mean diameter(GMD) on January 12, 21 and 17. In this study, we investigated mechanisms of new particle growth based on measurements using a high resolution time of flight aerosol mass spectrometer(HR-ToF-AMS) and a scanning mobility particle sizer(SMPS). On Event days(Jan 12 and 21), the total average growth rate was found to be 8.46 nm/h~24.76 nm/hr. These growth rate are comparable to those reported for other urban and rural sites in South Korea using different method. Comparing to the Non-Event day(Jan 17), New Particle Growth mostly occurred when solar radiation is peaked and relative humidity is low in daytime, moreover enhanced under the condition of higher precusors, NO₂ (39.9 vs 6.2ppb), VOCs(129.5 vs 84.6ppb), NH₃(11 vs 4.7ppb). The HR-ToF-AMS PM_1.0 composition shows Organic and Ammoniated nitrate were dominant species effected by emission source in domestic. On the other hand, The Fraction of Ammoniated sulfate was calculated to be approximately 16% and 31% when air quality is inflow from China. Longer term studies are needed to help resolve the relative contributions of each precusor species on new particle growth characteristics.

• Asian Journal of Turfgrass Science
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• v.20 no.1
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• pp.25-31
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• 2006

'Meyer' zoysiagrass(Zoysia japonica Steud.) is a popular turfgrass species used for transition zone golf course fairways and tees in mfd U.S.A golf courses because it is generally winter hardy while providing an excellent playing surface with minimal chemical and irrigation inputs. However, its functionality declines easily in many of the shaded areas of these courses. Reduced irradiance causes excessive shoot elongation, reduced tillering, and weak plants that are poorly suited to tolerate or recover from traffic and devoting. Trinexapac-ethyl (TE) effectively reduces gibberellic acid (GA) biosynthesis and subsequent shoot cell elongation. This study was initiated to evaluate TE effect on shoot elongation and stand persistence under two levels of shade in 'Meyer' zoysiagrass. A mature stand of 'Meyer' was treated with all combinations of three levels of shade(0%, 79%, and 92%) and three levels of monthly TE [0, 48 $g{\cdot}ha^{-1}$ a.i(0.5x) and 96 $g{\cdot}ha^{-1}$ a.i(1x)]. In full sun, the TE at 48 $g{\cdot}ha^{-1}$ a.i reduced clipping yield by 18% over a four-week period and, whereas the TE at 96 $g{\cdot}ha^{-1}$ a.i by 30% to 38%. Monthly application of TE at the 96 $g{\cdot}ha^{-1}$ a.i increased 'Meyer' tiller density in full sun and under 79% shade. Both rates of TE consistently reduced shoot growth under shade relative to the shaded control. Only the monthly applications of the TE at 96 $g{\cdot}ha^{-1}$ a.i consistently delayed loss of quality under 79% shade. Our results indicate TE can be an effective management practice to increase 'Meyer' zoysiagrass persistence in shaded environments.

• Korean Journal of Environment and Ecology
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• v.35 no.6
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• pp.644-658
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• 2021

Understanding the functional traits of dominant species in urban ecosystems provides insight into species' trait adaptation and ecosystem function in response to fragmented and isolated urban vegetation and reduced biological interactions. This study compared means and variances of environmental factors (geographic, meteorological, and soil attributes) and 4 leaf traits (leaf area, specific leaf area, leaf dry mass content, and leaf shape index) and 7 reproductive traits (fruit width, fruit length, fruit shape, fruit dry weight, fruit dry matter content, seed weight, and seed ratio) measured of 40 Sorbus alnifolia individuals in four mountainous areas south of Seoul downtown, South Korea. We then performed the multivariate analysis of trait combinations. While the measured environmental factors indicated the individuality of the survey sites, the urban vegetation was drier and had a longer growth period. The leaves of S. alnifolia in the urban areas were smaller and heavier, and the fruits produced longer and lighter seeds, showing the traits affected by long urbanization. The study confirmed changes in the growth and reproduction mechanism of the S. alnifolia population under the urban environment, indicating reduced biological interaction due to vegetation fragmentation and isolation. This study provides limited but distinct ecological information about the function and persistence of key species in cities with a reduced scale of biological interactions and many negative environmental factors such as air pollution.

• Korean Journal of Environment and Ecology
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• v.33 no.4
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• pp.422-439
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• 2019

The rear edge population is considered to have low genetic diversity and high risk of extinction according to a highly isolated distribution. However, the rear edge population is observed to have persisted for an extended period despite the low genetic diversity. As such, it is necessary to understand the ecological process involved in the persistence of the population. Viola mirabilis L. in Korea is considered the rear edge population from the perspective of the worldwide distribution. We surveyed the distribution range of V. mirabilis, which shows the isolated distribution in the central area of Korea, to find out the factors of its persistence. Next, we investigated and accessed the vegetational pattern of habitats, soil environment, phenology, self-compatibility, population structure, and extinction risk factors observed in the distribution area. V. mirabilis was distributed in the understory of the deciduous forest, planted forest of the deciduous conifer and deciduous broad-leaved trees, shrubland, and grassland in the limestone area. We also observed the re-establishment of seedlings in the population, and most of them showed a stable population structure. For chasmogamous flowers, the visit by pollinators has a significantly positive relationship with the production of fruits. However, we found that the production of the cleistogamous flowers was more numerous in all studied populations and that only the cleistogamous flowers were produced despite a more substantial plant size in some populations. The plant size was more related to the production of the cleistogamous flowers than that of the chasmogamous flowers. Accordingly, the cleistogamous flowers significantly contributed to seedling recruitment in the population. We found that the production of the chasmogamous flowers and the cleistogamous flowers did not have a correlation with the factors of the soil analysis except for phosphoric acid. V. mirabilis showed the self-incompatibility characteristics most likely due to the production capability of the cleistogamous flowers. Potential extinction risk factors observed in the distribution area was included the development of limestone mine, the expansion of agricultural fields, and the construction of houses. Although V. mirabilis showed an isolated distribution in the limestone area in the Korean peninsula, it showed a diverse distribution in a wide habitat environment ranging from the grassland to the understory of the trees with relatively low canopy closure rate. Moreover, we concluded that the persistence of the population was possible if we can maintain the current state of multiple populations and stable population structure.