• Korean Journal of Environment and Ecology
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• 제21권4호
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• pp.336-346
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• 2007

This study was conducted to evaluate the vegetation structure of 34 plots for inspection(plot unit: $100m^2$)of evergreen broad-leaved forest in Dongbaekdongsan(Mt.), Jeju-do, Korea. In accordance with the results of TWINSPAN and mean importance percentage analysis, the target forest was aged $28{\sim}52$, and classified into seven community types in total: Ilex rotunda community, Castanopsis sieboldii community, Castanopsis sieboldii-Quercus glauca community, Quercus glauca-Castanopsis sieboldii community, Quercus glauca community, Quercus glauca-Camellia japonica community, and Quercus glauca-Styrax japonica community. According to the results of importance percentage analysis and DBH class distribution of major woody species, the vegetational aspects showed that the dominant species were Castanopsis sieboldii and Quercus glauca in the canopy layer and Camellia japonica in the subordinate layer. Ilex rotunda and Quercus glauca-Styrax japonica community were damaged vegetation in the canopy layer. According to the index of Shannon's diversity in the six communities including the dominant species - Quercus glauca and Castanopsis sieboldii, their species diversity degree was $0.8745{\sim}1.3018$ and that of Ilex rotunda community was the lowest 0.7619. Camellia japonica, Eurya japonica, Ilex rotunda, Trachelospermum asiaticum var. intermedium, Ardisia crenata appeared in all the seven communities. In addition, Litsea coreana and Cinnamomum japonicum as well as Neolitsea serica presumed as climax species in the warm temperate climate also appeared and the constancy ratio of Cinnamomum japonicum was more than 80%. As a result, the target forest in Dongbaekdongsan(Mt.) was mainly compose of Castanopsis sieboldii and Quercus glauca in the canopy layer as a mixed vegetational pattern, and Cameliia japonica was dominant in the subordinate layer. Continuous monitoring was required, since Camellia japonica was strong in the subordinate layer in contrast to the weakness of Litsea coreana and Neolitsea serica reported as the species of climax stage in the forest with Evergreen Broad-leaved Vegetation at a viewpoint of successional direction.

• Journal of Food Hygiene and Safety
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• 제28권3호
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• pp.217-221
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• 2013

This study developed predictive models for the kinetic behavior of Staphylococcus aureus on processed cheeses. Mozzarella slice cheese and cheddar slice cheese were inoculated with 0.1 ml of a S. aureus strain mixture (ATCC13565, ATCC14458, ATCC23235, ATCC27664, and NCCP10826). The inoculated samples were then stored at $4^{\circ}C$ (1440 h), $15^{\circ}C$ (288 h), $25^{\circ}C$ (72 h), and $30^{\circ}C$ (48 h), and the growth of all bacteria and of S. aureus were enumerated on tryptic soy agar and mannitol salt agar, respectively. The Baranyi model was fitted to the growth data of S. aureus to calculate growth rate (${\mu}_{max}$; ${\log}CFU{\cdot}g^{-1}{\cdot}h^{-1}$), lag phase duration (LPD; h), lower asymptote (log CFU/g), and upper asymptote (log CFU/g). The growth parameters were further analyzed using the square root model as a function of temperature. The model performance was validated with observed data, and the root mean square error (RMSE) was calculated. At $4^{\circ}C$, S. aureus cell growth was not observed on either processed cheese, but S. aureus growth on the mozzarella and cheddar cheeses was observed at $15^{\circ}C$, $25^{\circ}C$, and $30^{\circ}C$. The ${\mu}_{max}$ values increased, but LPD values decreased as storage temperature increased. In addition, the developed models showed acceptable performance (RMSE = 0.3500-0.5344). This result indicates that the developed kinetic model should be useful in describing the growth pattern of S. aureus in processed cheeses.

• Korean Journal of Environmental Agriculture
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• 제38권4호
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• pp.225-236
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• 2019

BACKGROUND: Hydroponics is one of the methods for evaluating plant production using the inorganic nutrient solutions, which is applied under the artificial light conditions of plant factory system. However, the application of the conventional inorganic nutrients for hydroponics caused several environmental problems: waste from culture mediums and high nitrate concentration in plants. Organic nutrients are generally irrigated as a supplementary fertilizer for plant growth promotion under field or greenhouse conditions. Hydroponic culture using organic nutrients derived from the agricultural by-products such as dumped stems, leaves or immature fruits is rarely considered in plant factory system. Effect of organic or conventional inorganic nutrient solutions on the growth and nutrient absorption pattern of green and red leaf lettuces was investigated in this experiment under fluorescent lamps (FL) and mixture Light-Emitting Diodes (LEDs). METHODS AND RESULTS: Single solution of tomatoes (TJ) and kales (K) deriving from agricultural by-products including leaves or stems and its mixed solution (mixture ration 1:1) with conventional inorganic Yamazaki (Y) were supplied for hydroponics under the plant factory system. The Yamazaki solution was considered as a control. 'Jeockchima' and 'Cheongchima' lettuce seedlings (Lactuca sativa L.) were used as plant materials. The seedlings which developed 2~3 true leaves were grown under the light qualities of FL and mixed LED lights of blue plus red plus white of 1:2:1 mixture in energy ratio for 35 days. Light intensity of the light sources was controlled at 180 μmol/㎡/s on the culture bed. The single and mixture nutrient solutions of organic and/or inorganic components which controlled at 1.5 dS/m EC and 5.8 pH were regularly irrigated by the deep flow technique (DFT) system on the culture gutters. Number of unfolded leaves of the seedlings grown under the single or mixed nutrient solutions were significantly increased compared to the conventional Y treatment. Leaf extension of 'Jeockchima' under the mixture LED radiation condition was not affected by Y and YK or YTJ mixture treatments. SPAD value in 'Jeockchima' leaves exposed by FL under the YK mixture medium was approximately 45 % higher than under conventional Y treatment. Otherwise, the maximum SPAD value in the leaves of 'Cheongchima' seedlings was shown in YK treatment under the mixture LED lights. NO₃-N contents in Y treatment treated with inorganic nutrient at the end of the experiment were up to 75% declined rather than increased over 60 % in the K and TJ organic treatment. CONCLUSION: Growth of the seedlings was affected by the mixture treatments of the organic and inorganic solutions, although similar or lower dry weight was recorded than in the inorganic treatment Y under the plant factory system. Treatment Y containing the highest NO₃-N content among the considered nutrients influenced growth increment of the seedlings comparing to the other nutrients. However effect of the higher NO₃-N content in the seedling growth was different according to the light qualities considered in the experiment as shown in leaf expansion, pigmentation or dry weight promotion under the single or mixed nutrients.