• Animal Systematics, Evolution and Diversity
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• v.28 no.1
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• pp.36-41
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• 2012

The larvae of Chaoborus are widely distributed in lakes, ponds, and reservoirs. These omnivorous Chaoborus larvae are crucial predators and play a role in structuring zooplankton communities, especially for small-sized prey. Larvae of Chaoborus are commonly known to produce predator-induced polyphenism in Daphnia sp. Nevertheless, their taxonomy and molecular phylogeny are very poorly understood. As a fundamental study for understanding the role of Chaoborus in predator-prey interactions in a freshwater ecosystem, the molecular identification and phylogenetic relationship of Chaoborus were analyzed in this study. A molecular comparison based on partial mitochondrial cytochrome oxidase I (COI) between species in Chaoborus was carried out for the identification of Chaoborus larvae collected from 2 localities in Korea. According to the results, the Chaoborus species examined here was identified as C. flavicans, which is a lake-dwelling species. Furthermore, partial mitochondrial genome including COI, COII, ATP6, ATP8, COIII, and ND3 were also newly sequenced from the species and concatenated 5 gene sequences excluding ATP8 with another 9 dipteran species were compared to examine phylogenetic relationships of C. flavicans. The results suggested that Chaoborus was more related to the Ceratopogonidae than to the Culicidae. Further analysis based on complete mitochondrial DNA sequences and nuclear gene sequences will provide a more robust validation of the phylogenetic relationships of Chaoborus within dipteran lineages.

• The Korean Journal of Ecology
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• v.19 no.2
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• pp.125-139
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• 1996

The relationships between environmental factors and the establishment and growth of oak seelings were studied in the greenhouse. The early seedling performances of three oak species (Quercus mongolica, Quercus serrata, Quercus variabilis) were compared. Mean seed weight was the biggest in Q. variabilis, and the smallest in Q. serrata, and the germination rate was higher in Q. variabilis than in Q. mongolica and Q. serrata. The germination rate was significantly affected by seed weight class in Q. serrata, but not in Q. mongolica. Emergence of oak seedlings was similar in all three oak species, and especially the first leaf emergence increased about twenty days after germination. An experiment was designed using three environmental factors (light, soil moisture, fertilizer) to compare the response of the three oak species. Light and soil moisture significantly affected the seedling height growth of Q. variabilis, but the effect was marginal in Q. mongolica and Q. serrata. However, growth of seedling biomass was significant in all three oak species. In contrast, fertilizer did not affect seedling growth of any of the oak species. Q. variabilis is expected to grow well in large gaps because it is very sensitive and responds well to high light and high moisture conditions. Q. mongolica and Q. serrata are relatively tolerant to shade but may need gaps for the seelings to grow into saplings.

• Journal of Korean Society of Forest Science
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• v.4 no.1
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• pp.33-38
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• 1965

It has already been noted that some tree species, denoted as tolerant species, endure to behavior shadiness in growth than those species, denoted as intolerant species, since this fact of tolerance must be involved in silvicultural practice, the present author, with pinus rigida, pinus Thunbergii, and Buxus koreana, investigated the relation of degree of shadiness to soil moisture condition. Because tolerant and intolerant trees must be considered from the standpoint of their ability to use any of the factors that are likely to be at low concentration in the dense or open forest. The observed results may be summarized as follows : 1. The ability of tolerance of the species to shadiness is differently concluded by the base with which the analysis was made, i.c. Height, growth, diameter growth, T-R ratio or dry matter increase and so on. Regarding this point root collar increment or dry matter increase were considered more reasonable bases for discussing the tolerability. 2. When total length growth, including both stem and root, is taken as standard for the comparison of the ability of tolerance for each species, higher soil moisture condition and thicker shadeniss lessened the ability of pinus rigida, seedlings. Pinus Thunbergii, showed. However more moisture resistant than pinus rigida. Buxus koreana, seemed to have stronger ability of tolerance than any others. 3. When total dry matter content taken as standard, the results obtained are given in Fig, 3. In pinus rigida, the soil moisture supplemented the lack of light.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.258-261
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• 2007

Although there have been lack of studies using X-band SAR data particularly for forestry application as compared to C-, and L-band SAR data, it has a potential to distinguish tree species because most signals are backscattered on the top of canopy. This study aimed to compare signal characteristics of multi-band SAR data including X-band for classifying tree species. The data used for the study are SIR-C/X-SAR data (X-, C-, L-band) obtained on Oct. 3, 1994 over the forest area near Seoul, S. Korea. Thirty ground sample plots were collected per each tree species. Initial comparison of backscattering coefficients among three SAR bands shows that X-band data showed better separation of tree species than C- and L-band SAR data irrespective of polarization. The weak penetrating in canopy layer might be possible source of information for X-band data to be useful for the classification of forest species and cover type mapping.

• Journal of the Korean Wood Science and Technology
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• v.37 no.5
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• pp.451-458
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• 2009

Anatomical comparison of 8 North American species of Abies was executed to provide taxonomic information. The species of eastern (balsam and Fraser fir) and western (Pacific silver, white, grand, subalpine, California red, and noble fir) were found to be separated on the basis of crystals and color of contents in ray parenchyma cells and ray height. In eastern species, crystals in ray parenchyma cells were absent and ray parenchyma cell contents were colorless to very light. These two eastern species were further characterized by the absence of uniseriate rays exceeding 25 cells in height. In western species, only subalpine fir had colorless to very light contents but the remaining five species have dark contents in ray parenchyma cells. Crystals were absent to extremely sparse in Pacific silver fir, somewhat frequent in noble fir, frequent in grand and California red fir, and very frequent in white fir. Uniseriate rays exceeding 25 cells in height were regularly found in grand and California red fir but absent in white and noble fir.

• Animal Systematics, Evolution and Diversity
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• v.32 no.2
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• pp.105-111
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• 2016

The genetic structure of marine animals that inhabit the seashore is affected by numerous factors. Of these, gene flow and natural selection during recruitment have strong influences on the genetic structure of seashore-dwelling species that have larval periods. Relative contributions of these two factors to the genetic structure of marine species would be determined mainly by the duration of larval stage. The relationship between larval period and genetic structure of population has been rarely studied in Korea. In this study, genetic variations of cytochrome oxidase subunit I (COI) were analyzed in two dominant species on rocky shore habitats in the Korean peninsula: periwinkle Littorina brevicula and acorn barnacle Fistulobalanus albicostatus. Both species are not strongly structured and may have experienced recent population expansion. Unlike periwinkle, however, barnacle populations have considerable genetic variation, and show a bimodal pattern of mismatch distribution. These results suggest that barnacle populations are more affected by local adaptation rather than gene flow via larval migration. The bimodal patterns of barnacle populations observed in mismatch distribution plots imply that they may have experienced secondary contact. Further studies on seashore-dwelling species are expected to be useful in understanding the evolution of the coastal ecosystem around Korean waters.

• Journal of Life Science
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• v.14 no.4
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• pp.614-619
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• 2004

This study was undertaken to investigate the different responses of cultured plant cells to paraquat treatment and nucleus-DNA damage in relation to enzyme activity of superoxide dismutase (SOD). Furthermore, this study was also carried out to understand the antioxidative mechanism of plant cells to environmental stress. We selected two different species of plant cultured cells, Ipomoea batatas as high-SOD species and Lonicera japonica as low-SOD species. The total activity and specific activity of SOD in a chlorophyllous cell of I. batatas were 3,736 unit/gㆍfresh weight and 547 unit/mgㆍprotein, respectively, and those in L. japonica were 23 unit/gㆍfresh weight and 13 unit/mgㆍprotein, respectively SOD activity in chlorophyllous I. batatas cells reached its maximum level at 10 to 15 days after subculture, whereas that in L. japonica remained at a very low SOD level during the whole period of subculture. In comparison to L. japonica, I. batatas, a high-SOD species, showed high tolerance to paraquat 10 and 50 mg/l treatment in terms of cell viability and electrolyte leakage. Based on the result of comet assay, the nucleus-DNA damage of two species by paraquat 50 mg/l treatment was not significantly different. However, I. batatas cells repaired their damaged DNA more effectively than the cells of the low-SOD species, L. japonica.

• Korean Journal of Environment and Ecology
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• v.29 no.1
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• pp.69-80
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• 2015

Studies on Trapa of Korean, Japanese, and Chinese origins have been generally limited to currently living Trapa, thereby demonstrating the lack of phylogenetic approaches. In the present study, we conducted a numerical taxonomic study on 34 Korean origin Trapa species newly discovered in peat deposits. By using the numerical taxonomy as well as geological data, we created an appearance map based on the periods and taxonomic groups of the Korean Trapa. Further, by using this appearance map, we reviewed the limitations that exist in the taxa and simultaneously discussed the adaptational environment of Trapa in each period. Although other studies have discussed new variants of Trapa worldwide, including T. litwinowii V. vassil. var. chihuensis S.F.Guan & Q.Lang of China (Guan and Lang, 1987), the present study is significant because it provides data on the origin of Korean Trapa species. The availability of such data is essential in determining the adaptational environment of the presently living Trapa. To our knowledge, this is the first report of approximately 10 newly discovered and other presently living species of Trapa. Further, the appearance map in the present study allows the use of the 10 newly discovered species and variants of 34 Trapa species indigenous to South Korea for over 1000 years, for a comparison with the currently living Trapa species. Thus, the present study results could serve as important basic data to understand the adaptational environment of the genus Trapa. from the past to the present in Korea.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.12
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• pp.1009-1016
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• 2007

Numerical study on preferential diffusion effects in flame structure in $CH_4-H_2$ diffusion flames is conducted with detailed chemistry. Comparison of flame structures with mixture-averaged species diffusion and suppression of the diffusivities of $H_2$ and H was made. Discernible differences in flame structures are displayed with three species diffusion models. The behaviors of maximum flame temperatures with those species diffusion models are not explained by scalar dissipation rate but by the nature of chemical kinetics. It is seen that the modifcation of flame structure is mainly due to the preferential diffusion of H2 and thereby the nature of chemical kinetics. It is also found that the behaviors of major species with the three species diffusion models are addressed to the nature of chemical kinetics, and this is evident by examining importantly contributing reaction steps to the production and destruction of those chemical species.

• Korean Journal of Organic Agriculture
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• v.3 no.1
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• pp.23-42
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• 1994

This paper studied earthworm populations in fields under practical cultivation in the Eastern Harzforeland (Germany). The examined sites differed insignificantly in their climatic and soil conditions. The examination was a comparison between a field and a narrow edge or meadow. A combination of Oktett method and handsortin was used. The five different habitates seven earthworm species were discoverd. The most frequently foundd were A. rosea, A. caliginosa, and A. chlorotica. There were clear differences in species between the habitates of each site. Generally the edge or the meadow contained one (Zoeberitz) or two (Zscherben) more species than the field. The composition of species differed between 1990 and 1992. In the dry Autumn of 1991 there were less species found at both sites. The occurance of earthworm species depends on the weather. Moisture influencing similiarity of abundance and bio-mass were recorded in three out of four habitates. Starting on a high level in Autumn 1990 the abundance as well as biomass decreased until Autumn 1991 and increased the following year. The number from 1990 were never reached again during the examination. One year of normal precipita-tion was not enough to return the population to the beginning level. Great differences in the number of earthworms between the compared habitats suggest that the edges and meadows are a potential immigration source into a field which is poor on earthworms. Structrues of distribution near the edge refer to a migration from a high populated edge into an almost empty field.