• Journal of The Geomorphological Association of Korea
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• v.24 no.1
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• pp.63-76
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• 2017

This research was classified mountain areas with high ecological, environmental and resource value among the macro scaled terrain that can be checked at the space scale of less than 1:1,000,000 and analyzed the topographical characteristics. It has been confirmed that the mountains of the Korean peninsula belong to the groups IV, V, VI(classification by Kapos et al.(2000)) as a result of applying the quantitative standards for designation of mountain areas to the global mountain system. The area of mountains calculated using high resolution DEM is equivalent to 48% of the area of the Korean peninsula, and the result is quite different from the general idea of which 70% is the mountain area of the Korean peninsula. The mountain areas show the distribution of geomorphons, that is different from the plains and the hills and also, it shows the differences between the mountains of the groups IV~ VI classified according to the altitude. As a result of analyzing the relations among type pattern, slope, and relief, specific geomorphons are concentrated at $10^{\circ}$ and $20^{\circ}$ and it shows the possibility to classify the mountainous areas into two groups based on the result that the distribution of landform patterns are bimodal in the relation to the amount of relief.

• Ocean and Polar Research
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• v.34 no.2
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• pp.165-173
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• 2012

A 26 day experiment was conducted to determine the effects of feeding and starvation on the survival, morphology, and histology in chum salmon (Oncorhynchus keta) fry. We included three experimental groups: starved, fed, and initial. The survival and growth rates were lower in the starved group than in the fed group (P < 0.05). In the starved group, survival began to decline after 16 days, and all fish had died after 26 days. We determined the effects of starvation on the morphometric parameters using the truss and classical dimensions. The dimensions in the head region were larger in the starved group than in the initial and fed groups. In contrast, the truss dimensions of the fed group were larger than those of the initial and starved groups. Starvation reduced the heights of the hepatocyte nuclei and of the intestinal epithelium (P < 0.05). The starved group also showed atrophy of the digestive structures and shrinkage of the foregut and midgut. Starvation led to the degeneration and atrophy of the exocrine pancreas, in which the lumen was markedly diminished and the folds of mucosa were less apparent. The hepatocyte morphology in the starved group was abnormal compared with that of the initial and fed groups, with highly compact, irregularly shrunken nuclei. Melanomacrophages were randomly distributed in the kidneys of the starved group, and their abundance increased rapidly during the experiment. In contrast, neither the initial nor fed group had any melanomacrophages. These results suggest that the nutritional parameters used in this study are useful indices of nutritional status in chum salmon.

• The Plant Pathology Journal
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• v.38 no.4
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• pp.323-333
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• 2022

Filenchus cylindricus (Thorne & Malek, 1968) Niblack & Bernard, 1985 was reported from the sandy rhizospheric soils of Poa pratensis and for the first time in Korea. Females and males are molecularly characterized and morphological and morphometric data supplied. Identification was made using an integrative approach considering morphological characteristics and inferences drawn from the analyses of the D2-D3 expansion segment of 28S rRNA and ITS1-5.8S-ITS2 of rRNA partial sequences. Females and males from Korea conform to the type descriptions and also to subsequent species descriptions from Iowa and Colorado USA, Sudan and Pakistan. Despite the close morphological and morphometric similarities with F. thornei (Andrássy, 1954) Andrássy, 1963, the two species can be adequately differentiated based on molecular data inference.

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.55-67
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• 2021

A 210-day experiment was conducted to examine the effects of starvation on survival, external morphometric traits, and sectioned morphometric traits in Far Eastern catfish(Silurus asotus). The survival rate decreased to 92.2±0.47% in the fed group and to 74.4±2.59% in the starved group. Eight dimensions of Ls, DALPO/Ls, DADOP/Ls, ED/Ls, CH/Ls, BDAA/Ls, BDMA/Ls, and BWAA/Ls showed significant differences (p<0.05), and 16 other dimensions of DALAD/Ls, DPDPL/Ls, HPLAA/Ls, HALAV/Ls, HALOP/Ls, DAUPO/Ls, DADAV/Ls, DADAA/Ls, Max BL/Ls, Man BL/Ls, LD/Ls, HWOP/Ls, DAUF/HL, DAUS/HL, IW/HL, and DAUE/HL were not significantly different among the initial, fed, and starved groups (p>0.05). The fed group showed higher total height (THX), wider width (WX), and larger area (AX) than those of the starved group in each body section. This research provides information on the morphometric traits and body sections of starved Far Eastern catfish. These results can be used as a basic guide to indicate nutritional status and assist in aquaculture methods for Far Eastern catfish. Moreover, the methods used in this study were considered helpful because the survey analysis method can be used to investigate information on the nutritional status of other fish species.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.236-240
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• 2009

Tylenchulus semipenetrans, citrus nematode is an important phytopathogenic nematode and responsible for serious damage on citrus. However, little information is available about genetic variability of T. semipenetrans among different populations with variation of conventional diagnostic characteristics. In this study, we compared the morphometric and genetic characteristics among different populations. The mature female of T. semipenetrans collected in this study had thicker cuticle than those in the previous studies. In comparative sequence analysis of T. semipenetrans populations obtained from Jeju in Korea, we observed genetic variations within clones generated from single individuals. To determine whether variability among copies of nuclear ribosomal DNA sequences exists in the genome of T. semipenetrans, PCR-RFLP technique from individuals of Korean isolates with MseI and MspI restriction enzymes was used to prove experimentally that all populations have intra-specific variations. Restriction enzyme digestion created several fragments on 3.0% agarose gel corresponding to several haplotypes in all populations, though some populations displayed fragment deletion. The total length of fragments was larger than before digestion, indicating sequence heterogeneity within the genome of T. semipenetrans.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.173-180
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• 1992

A feature typical of natural rivers is the bend. The purpose of this study is to examine hydraulic and morphometric characteristics in channel bend reach by the deterministic approach. Cross section shape factor, "As" is suggested for a new cahracteristic factor of channel bend reach analysis. The variation of this new factor along the river reach showed the location of the concentration of the force due to the current all over the reach, that is curved or not. Some general meander factors are used for correlation with new factor suggested, and the applicability of "As" is verified. The range R/W values are concentrated 2~4, the meanning of this value can be regarded to the warning for bank erosion or breaking. And this paper dealt with prediction of cross section bed shape variation.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.399-408
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• 2022

There has been much debate on the morphometric divergence between the recently identified Apis cerana koreana and Apis cerana honey bees. The aim of this study was to obtain phenotypic information that can be used to compare A. c. koreana data with other A. cerana subspecies data from open resources and determine breeding results on the basis of morphometric traits. To differentiate A. c. koreana, we investigated 22 classic morphological characteristics; royal jelly secretion; and the weight of workers, queens, and drones of A. c. koreana bred in Korea. To define the selection results, we used the geometric morphometric method. The artificially selected A. c. koreana secreted significantly more royal jelly (1.18 times) than the naturally selected A. c. koreana, which positively influenced the health of the colonies. These honey bees were identified more clearly with the geometric morphometric method than with the classic morphometric method, which is traditionally used to determine the subspecies. Large trends were noted for A. c. koreana on the basis of our results and literature from the 1980s regarding A. cerana sizes in Korea (tarsal index, length of forewing, and cubital index were measured). The cluster analysis revealed the proximity of A. c. koreana, A. cerana in China, and A. c. indica on the basis of eight classic characters, which, perhaps, relay the origin of the honey bees. The results of this study defined the morphometric responses of A. c. koreana honey bees to geographic isolation, climate change, and selection, which are important to identify, protect, and preserve honey bee stock in Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.2
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• pp.198-207
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• 2016

Tanaka’s snailfish, Liparis tanakae (Gilbert and Burke, 1912), is distributed throughout the coasts of Korea. To clarify the population structure of L. tanakae, we analyzed the morphological and genetic variation among individuals sampled from three localities surrounding the Korean peninsula: Boryeong in the Yellow Sea, Jinhae in the Korea Strait and Pohang in the East Sea. Principal component analysis based on 20 morphometric characteristics revealed two slightly distinct groups (Boryeong vs. Jinhae and Pohang). However, canonical discriminant analysis clearly revealed three groups, separated according to locality. Pairwise differentiation index (F_ST) comparisons based on 762-base pairs mitochondrial cytochrome b gene sequences showed that Boryeong significantly differed from Jinhae and Pohang, but Jinhae and Pohang did not significantly differ from each other. Our findings suggest that Korean L. tanakae comprise at least two groups. Further studies using more sensitive DNA markers, such as microsatellite DNA, are required.

• Water Engineering Research
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• v.6 no.2
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• pp.91-99
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• 2005

One of the most important factors for estimating a flood runoff from streams is the lag time. It is well known that the lag time is affected by the morphometric properties of basin which can be expressed by catchment shape descriptors. In this paper, the notion of the geometric characteristics of an equivalent ellipse proposed by Moussa(2003) was applied for calculating the lag time of geomorphologic instantaneous unit hydrograph(GIUH) at a basin outlet. The lag time was obtained from the observed data of rainfall and runoff by using the method of moments and the procedure based on geomorphology was used for GIUH. The relationships between the basin morphometric properties and the hydrological response were discussed based on application to 3 catchments in Korea. Additionally, the shapes of equivalent ellipse were examined how they are transformed from upstream area to downstream one. As a result, the relationship between the lag time and descriptors was shown to be close, and the shape of ellipse was presented to approach a circle along the river downwards. These results may be expanded to the estimation of hydrological response of ungauged catchment.

• Journal of Species Research
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• v.11 no.2
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• pp.98-101
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• 2022

The genus Tripylina Brzeski, 1963 is a group of terrestrial nematodes that inhabit soil and semi-wet biomes, most of which have been reported from Europe, Asia, America, Africa, and New Zealand. Tripylina stramenti (Yeates, 1971) Tsalolikhin, 1983, belonging to the family Trischistomatidae Andrassy, 2007, is newly discovered from Korea. The specimens were collected from the edge of the valley of Ulleung-gun, Gyeongsangbuk-do, South Korea. Tripylina stramenti described herein shows typical morphological characters of the genus Tripylina, including six and four setae in a single whorl, present dorsal tooth and subventral teeth, prodelphic reproductive system of female, absence post-uterine sac, narrow sickle-shaped spicule of male and generally S-shaped tail. The specimens differ in their body width (from the New Zealand populations), outer labial setae length, cuticles thickness(from the West African populations), and nerve ring position (from Indian populations). This species is distinguished from other Tripylina species by its relatively large body, two anterior and subventral teeth, and single cervical seta. In this study, morphological characteristics and morphometric information of the Korean T. stramenti isolate are described, illustrated, and compared with the same species from other geographic origins.