• Applied Microscopy
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• v.40 no.3
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• pp.169-176
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• 2010

Black molly (Poecilia sphenops) and sailfin molly (Poecilia latipinna) are a teleost belonging to Poeciliidae. The spermatogenesis between two species were investigated by light and electron microscope. The whitish testes of both black molly and sailfin molly were located between intestine and air bladder. The size of testis was major axis 7 mm, minor axis 2 mm. The testis contained numerous testicular cysts. In both black molly and sailfin, primary spermatocytes were comparatively large ellipsoidal, and mitochondria showed a marked development. The secondary spermatocyte was smaller than that of primary spermatocyte, highly condensed according to their development. The nucleus with electron-dense was round shape and flagella started to be formed. In spermiogenesis, chromatin was more condensed. The mitochondria were rearranged along the tail. The number of mitochondria was 2 to 4 in cross section and 8 to 10 in longitudinal section. The head of mature sperm was long cone shape and had not acrosome. The microtubules of flagella were arranged 9+2 structure. Also, the tail of sperm have lateral fins. In conclusion, spermatogenesis and sperm morphologies of these two species were same. These morphological similarity seems to be an indication of the Poeciliidae.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.951-963
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• 2009

The community structure and ecological characteristics of fish community in Lake Paldang were investigated from May to September 2008. During the survey period, 53 species belonging to 13 families were collected. Dominant species was Squalidus japonicus coreanus representing 81.8% of total number and 25.7% of total biomass of collected fish and subdominant species was Lepomis macrochirus representing 3.3% of total number and 18.9% of total biomass of collected fish. There were 20 Korean endemic species (38% of collected species number) including Cottus koreanus and 4 exotic species (7.5%) including Micropterus salmoides. The similarity analysis of fish communities among water areas of Lake Paldang using UPGMA showed that fish community of North-Han River was similar to that of South-Han River area and was different from that of Gyeongan River area. Long-term variation of fish community from 1972 to present study in Lake Paldang showed decrease of the species numbers after dam construction until 1994, and gradual increase from 1996 to present study indicating the disturbance of lentic system by dam construction in the 1980s. The increase of species number in the late 2000s may results in part from the increase of survey sites of successive studies. L. macrochirus which was designated as a domestic ecosystem-disturbing alien species with wide food niche have shown more than 20% of relative abundance since 1996 indicating the adverse effect on not only fish community but also aquatic ecosystem food web of Lake Paldang.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.1
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• pp.45-62
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• 2010

Zero plane displacement (d) is the elevated height of the apparent momentum sink exerted by the vegetation on the air. For a vegetative canopy, d depends on the roughness structure of a plant canopy such as leaf area index, canopy height and canopy density, and thus is critical for the analysis of canopy turbulence and the calculation of surface scalar fluxes. In this research note, we estimated d at the Gwangneung coniferous forest by employing two independent methods of Rotach (1994) and Martano (2000), which require only a single-level eddy-covariance measurement. In general, these two methods provided comparable estimates of $d/h_c$ (where $h_c$ is the canopy height, i.e., ~23m), which ranged from 0.51 to 0.97 depending on wind directions. These estimates of $d/h_c$ were within the ranges (i.e., 0.64~0.94) reported from other forests in the literature but were sensitive to the forms of the nondimensional functions for atmospheric stability. Our finding indicates that one should be careful in interepreation of zero plane displacement estimated from a single-level eddy covariance measurement that is conductaed within the roughness sublayer.

• Horticultural Science & Technology
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• v.29 no.2
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• pp.116-122
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• 2011

In this study, we report the generation and analysis of 1,392 expressed sequence tags (ESTs) from Korean Stewartia (Stewartia koreana Nakai). A cDNA library was generated from the young leaf tissue and a total of 1,392 cDNA were partially sequenced. EST and unigene sequence quality were determined by computational filtering, manual review, and BLAST analyses. Finally, 1,301 ESTs were acquired after the removal of the vector sequence and filtering over a minimum length 100 nucleotides. A total of 893 unigene, consisting of 150 contigs and 743 singletons, was identified after assembling. Also, we identified 95 new microsatellite-containing sequences from the unigenes and classified the structure according to their repeat unit. According to homology search with BLASTX against the NCBI database, 65% of ESTs were homologous with known function and 11.6% of ESTs were matched with putative or unknown function. The remaining 23.2% of ESTs showed no significant similarity to any protein sequences found in the public database. Annotation based searches against multiple databases including wine grape and populus sequences helped to identify putative functions of ESTs and unigenes. Gene ontology (GO) classification showed that the most abundant GO terms were transport, nucleotide binding, plastid, in terms biological process, molecular function and cellular component, respectively. The sequence data will be used to characterize potential roles of new genes in Stewartia and provided for the useful tools as a genetic resource.

• Journal of Periodontal and Implant Science
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• v.36 no.3
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• pp.613-625
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• 2006

Periodontal ligament(PDL) cells and human gingival fibroblasts(HGFs) play important roles in development, regeneration, normal function, and pathologic alteration. PDL cells and HGFs have the similarity related with general characteristics of fibroblast such as spindle shaped morphology, the presence of vimentin intermediate filament and the synthesis of interstitial collagens and fibronectin. There were many studies about the differences between PDL cells and HGFs, but they were not about whole gene level. In this study, we tried to explain the differences of gene expression profiles between PDL cells and HGFs, and the differences among three individuals by screening gene expression patterns of PDL cells and HGFs, using cDNA microarray. Although there were some variants among three experiments, a set of genes were consistentely and differentially expressed in one cell type. Among 3,063 genes, 49 genes were more highly expressed in PDL cells and 12 genes were more highly expressed in HGFs. The genes related with cell structure and motility were expressed more highly in PDL cells. These are cofilin 1, proteoglycan 1 secretory granule, collagen type I(${\alpha}$ 1), adducin gamma subunit, collagen type III(${\alpha}$ 1), fibronectin, lumican(keratan sulfate proteoglycan), and ${\alpha}$ -smooth muscle actin. Tissue inhibitor of metalloproteinase known as the enzyme controlling extracellular matrix with matrix metalloproteinase is more highly expressed in PDL cells, osteoprotegerin known as osteoclastogenesis inhibitory factor is more highly expressed in HGFs. We performed northern blot to verify cDNA microarray results on selected genes such as tissue inhibitor of metalloproteinase, fibronectin, osteoprogeterin. The result of northern blot analysis showed that each cell expressed the genes in similar pattern with cDNA microarray result. This result indicates that cDNA microarray is a reliable method in screening of gene expression profiles.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.1
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• pp.77-94
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• 2012

The purpose of this study is to analyze the process of vertical fragmentation of regional industries in Korea using Revealed Comparative Advantage index (RCA) and Average Propagation Length (APL). First of all, the competitiveness in regional export and substitution of regional imports were strong in the Electricity, Gas, and Water supply sector in Gyeongnam, and consumer-oriented Manufacturing sector in Incheon, Gyeongnam, and Gwangju. The high values of the APL were also found in the regions with common similarity with respect to the industrial structure and the sectors with indirect effects. In addition, the industrial sectors with high quality of infrastructure, and endowed services tended to be located in the beginning of the production chain. FInally, since manufacturing and service sectors in Seoul has higher APL, they could lead the growth of other related industries as key sectors, in the production fragmentation.

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.147-153
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• 2018

There are few available studies for insect diversity in relation to coastal dune despite the unique landscape features and high conservation value. Therefore, this study compared ground beetle assemblages inhabiting between windbreak forests and sand dunes in the Taeanhaean National Park. It investigated five windbreak forests and three coastal dunes using pitfall traps from middle of June to middle of October in 2014. A total of 2,335 ground beetles belonging to 30 species of 15 genera were collected. Synuchus arcuarticollis (158 individuals) and Dolichus halensis halensis (153 individuals) were dominant of 25 specifies collected from sand dunes while Synuchus arcuarticollis (1,630 individuals), Synuchus nitidus (130 individuals), and Synuchus cycloderus (42 individuals) were dominant of 14 species collected from windbreak forests. The similarity of ground beetles compositions in sand dunes and windbreak forests was significantly low at 27.4%. The results of this study showed that sand dune geographical features found in the Taeanhaean National Park had different insect assemblages from windbreak forests. It will be the useful information for conservation of insects in the future.

• Journal of Life Science
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• v.23 no.3
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• pp.406-414
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• 2013

The influence of a gradual increase in salinity on the diversity of aquatic bacterial in rivers was demonstrated. The denaturing gradient gel electrophoresis (DGGE) was used to analyze the bacterial community shift downstream in the Hyeongsan River until it joins the open ocean. Four water samples were taken from the river showing the salinity gradients of 0.02%, 1.48%, 2.63%, and 3.62%. The samples were collected from four arbitrary stations in 2.91 km intervals on average, and a DGGE analysis was performed. Based on the results of this analysis, phylogenetic similarity identification, tree analysis, and a comparison of each station were performed. The results strongly suggested that the response of the bacterial community response was concomitant to gradual changes in salinity, which implies that salt concentration is a major factor in shifting the microbiota in aquatic habitats. The results also imply a huge diversity in a relatively small area upstream from the river mouth, compared to that in open oceans or coastal regions. Therefore, areas downstream towards a river mouth or delta are could be good starting points in the search for new bacterial species and strains ("biotypes").

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.6
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• pp.60-68
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• 2015

Recent proliferation of advanced technologies such as wireless communication, mobile, sensor technology and so on has caused significant changes in a traffic environment. Human beings, in particular drivers, as well as roads and vehicles were advanced on information, intelligence and automation thanks to those advanced technologies; Intelligent Transport Systems (ITS) and autonomous vehicles are the results of changes in a traffic environment. This study proposed considerations when designing a simulation model for future transportation environments, which are difficult to predict the change by means of advanced technologies. First of all, approximability, flexibility and scalability were defined as a macroscopic concept for a simulation model design. For actual similarity, calibration is one of the most important steps in simulation, and Physical layer and MAC layer should be considered for the implementation of the communication characteristics. Interface, such as API, for inserting the additional models of future traffic environments should be considered. A flexible design based on compatibility is more important rather than a massive structure with inherent many functions. Distributed computing with optimized H/W and S/W together is required for experimental scale. The results of this study are expected to be used to the design of future traffic simulation.

• Korean Journal of Environment and Ecology
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• v.19 no.1
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• pp.19-30
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• 2005

The objective of this study was to monitor the edge vegetation development process after timber harvesting at deciduous hardwood forest in Seoul National University Forests of Baekwoonsan(Mt), Korea. From 1994 to 1999, Woody plants were monitored on two experimental plots established in 1994. The edge vegetation development pattern during the last six years(1994-1999) after timber harvesting is summarized as follows; Weigela subsessilis, Lindera erythrocarpa, Stephanandra incisa, Zanthoxylum schinifolium appeared to be a competitive species at the harvested forest edge. Staphylea bumalda, Lindera erythrocarpa, Viburnum erosum appeared to be a competitive species at harvested forest border between the harvested forest edge and the harvested interior. Weigela subsessilis, finders erythrocarpa, Lindera obtusiloba appeared to be a competitive species at the forest interior. The mean relative important value of major species were changed along the distance from the forest edge to the forest interior and seemed to be affected by aspect, and existing woody plants. But similarity indices seemed to be affected by distance. Species composition of forest edge(0-10m) was dissimilar to that of the other forest edge(40-50m). Species diversity indices, number of species and individuals were decreased according to the distance from the forest edge to the forest interior with passing time.