• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.359-369
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• 2001

Polymerase chain reaction (PCR) amplification of DNA as 30 different arbitrary primers and random amplified polymorphic DNAs (RAPD) analysis were performed on genomic DNA extracted from the blood of the marine rockfish (Sebastes schlegeli) from the Yellow Sea and the Southern Sea. The unique properties of the genomic DNA were used to investigate the features of the population dynamics and origins of the species. Out of 30 primers, seven generated 207 highly reproducible RAPD polymorphic products, producing approximately 2.7 polymorphic bands per primer. About 67.4% of total amplified products (307) were either polymorphic (207) to rockfish. The degree of similarity varied from 0.22 to 0.63 as calculated by bandsharing analysis. Also, the average level of bandsharing was 0.39$\pm$0.02 within the rockfish strains. The electrophoretic analysis of RAPD-PCR products showed the relatively high levels if variation between different individuals in rockfish from the Yellow Sea. However, the RAPD outlines obtained with DNA of different rockfish strains from the Yellow Sea and the Southern Sea in Korea were very similar. Also, a small number of polymorphic bands were identified. Even if further analyses or more rockfish populations are required, this result implies RAPD analysis reflects genetic differences between the geographical strains of the rockfish.

• The Korean Journal of Mycology
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• v.43 no.4
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• pp.281-285
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• 2015

This study was conducted to examine changes in the fungal community on fallen leaves of pear by treatment with lime sulfur. Although the lime sulfur could reduce the primary inoculum of several pathogens on spring season, the effect of lime sulfur has not been well determined scientifically. Fallen leaves infected by pear diseases in pear orchards in Naju were collected and treated with lime sulfur or water as a control. To determine the fungal diversity from each treatment, rDNA internal transcribed spacer (ITS) regions were analyzed after extraction of fungal genomic DNA from lime sulfur-treated or water-treated fallen leaves, respectively. The most common fungal species were Ascomycota and Basidiomycota in both treated leaves. However, the population dynamics of several fungal species including Alternari sp., Cladosporium sp., and Phomopsis sp., which are known as pear pathogens for skin sooty dapple disease, were quite different from each treated leaves. These results indicated that lime sulfur treatment led to changes of fungal communities on pear fallen leaves and could be applicable as a dormant spray.

• Weed & Turfgrass Science
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• v.5 no.2
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• pp.71-81
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• 2016

This study was conducted to investigate the weed occurrence and distribution on the orchard fields (apple, pear, peach, grape) at 387 sites in Chungbuk province of Korea from May to September in 2015. From the result of this survey, 200 weed species in 47 families were identified and classified to 82 annuals, 40 biennials and 78 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province orchard fields were higher in order of Digitaria ciliaris (4.12%), Echinochloa crus-galli (3.60%), Stellaria aquatica (3.45%), Artemisia princeps (3.07%) and Chenopodium album (3.06%). The composition of major occurred weed families, Compositae, Poaceae, Leguminosae and Cyperaceae were 21, 9, 6 and 6%, respectively. Coefficient of similarity between a various orchards based on the degree of dominance were ranged from 68.7-91.8%. The most important weed species at apple, peach, grape was Digitaria ciliaris while these for pear was Poa annua. Fifty-one exotic weed species were also identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the orchard fields in Chungbuk province of Korea.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.295-307
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• 2015

Surveys of weed species in paddy fields were conducted to identify weed occurrence on July 2013. Total 237 sites of paddy fields in 9 City/Gun, Jeonnam Provinces in Korea were investigated. From the survey, 45 weed species in 18 families were identified and classified to 33 annuals and 15 perennials. Based on the occurrence ratio, the most weed species belonged to Poaceae (9 species) and 8 and 4 weed species belonged to Cyperaceae and Scrophulariaceae, respectively. These 21 weed species in the most four families accounted for 46% of total weed occurrence. The most dominant weed species in Korean paddy fields were Echinochloa spp. (18.5%), followed by Monochoria vaginalis (12.3%), Lemna perpusilla (8.2), Eleocharis kuroguwai (5.2%) and Scirpus juncoides (5.2%). The most dominant weed species in machine transplanting paddy fields were Echinochloa spp. (14%), followed by Monochoria vaginalis (12%) and in water seeded rice paddy fields were Echinochloa spp. (25%), followed by Monochoria vaginalis (11%). This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in paddy fields.

• Korean Journal of Social Welfare
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• v.1
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• pp.51-71
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• 1979

During last five years several workshops and seminars among social work educators, in and out country, has taken place. In those gatherings there has been, criticism on American model on which curriculum of social work in Korea has mainly based, and many proposals which most developing countries should consider and adopt for developing their own curriculums. The proposals could be summarized as follows; 1. Specification of developmental functions of social work should be made so that the curriculum could involve. It also must come from own societal needs and own national development task. 2. Social work should participate and make contribution to plan and solve the main social problems in own countries. 3. Clarification of educational objective in undergraduate level should be made and one of them must be related to the first professional degree. 4. There should be the courses which provide the content of macro level participation. How much of the proposals are reflected in the current curriculum of Korea? What are the problems Korean social work education has been faced in connection with reflecting the proposals? What kinds of task we should or could perform in order to adopt the proposals? These are the questions which deserved to be studied. The followings are the answers to the questions; 1. The new courses such as social welfare policy and planning, Social Development, Population Dynamics and Family Planning, Social problems, Special Issues in Social Welfare, etc, are placed in the curriculum. 2. Though the new courses are added the courses of case work, group work, and community organization are strongly remained it means that integrative method is not quite adopted and that conflicts are taking place between new and old fashion. 3. Fieldwork placement policy has been changes from concurrent to block and from social work method oriented to social problem oriented. 4. There are lack of integration among the all courses, of consistency between pre and post courses and connection among the related courses. 5. Establishment of image of social worker with B, A. degree should be urgently taken place. It can't be done by social work field alone but by cooperation with all the forces related to the social work practice. 6. B. A. graduate should have a common base of knowledge and competence. It could be come from the clear and specified objectives of undergraduate level education. And agreement among the member schools on the objectives can call on the fundamental similarities in each curriculums. Different programs from one school to another can be tolerated as long as there are fundamental similarities among the schools. Basic concepts and framework of social work should be kept clearly. It is a slow and long process to make social work recognized as a profession in the developing countries. Korea can't be and exception. Failure of having social work be indegenous can't be the reason to refuse an change the basic concepts of social work. One of he most important task which social work education in Korea must achieve in the near future is to establish the minimum requirement courses in the curriculum. Social work field, on the other hand, must find the positions for the social works in the various settings and institute. Clear role and image of social worker can be obtained by doing that.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.95-103
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• 2015

In this study, we surveyed the distribution pattern and dominance of weeds occurred in four summer crop fields, hot pepper, soybean, maize, and Chinese cabbage in Gyeongbuk province. The weeds were summarized as 32 family and 132 species in hot pepper field, 31 family and 116 species in soybean field, 37 family 134 species in maize field, finally 35 family and 170 species in Chinese cabbage field. Among these weeds occurred in the four summer crop fields, the compositae was commonly dominant family, it occupied 17.4% in hot pepper field, 18.1% in soybean field, 11.9% in maize field, and 16.5% in Chinese cabbage field. The major five families including compositatae, graminae, polygonaceae, convolvulaceae and cruciferae were occupied 43.2% in hot pepper field, 47.4% in soybean field, 42.5% in maize field, and 43.5% in Chinese cabbage field, respectively. Furthermore, the most dominant weed in the hot pepper, soybean, maize, and Chinese cabbage fields was Portulaca oleracea, Digitaria ciliaris, and Rorippa palustris, respectively. This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in food crop fields of Gyeongbuk province.

• Journal of Korean Society on Water Environment
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• v.34 no.4
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• pp.363-374
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• 2018

The Han River serves as an important water resource for the city of Seoul, Korea and in the neighboring metropolitan areas. From the Paldang dam to the Jamsil submerged weir, the 4 water intake stations that are located for the Seoul metropolitan population were under review in this study. Therefore the water quality management in this section is very important to monitor, analyze and review to rule out any safety concerns. In this study, a 3-D hydrodynamic model, EFDC (Environmental Fluid Dynamics Code), was applied to the downstream of the Paldang Dam in the Han River, which is about 23 km in length, to determine issues related to water resource management. The 3-D grid was composed of 2,168 horizontal grids and three vertical layers. In this case, the hydrodynamic model was calibrated and verified with an observed average daily water surface elevation, water temperature and flow rate data for 3 years (2013~2015). The developed EFDC model proved to reproduce the hydrodynamics of the Han River well. The composition ratios of the noted incoming flows at the monitored intake stations for 3 years and their flow patterns in the river were analyzed using the validated model. It was found that the flow of the Wangsuk Stream depended on the Paldnag dam discharge, and it was noted that the composition ratios of the stream at the intake stations changed accordingly. In a word, the Wangsuk Stream moved mainly along the right bank of the Han River under the condition of a normal dam flow. As can be seen, when the dam discharge rate was low, the incidence of lateral mixing was often seen. The scenario analyses were also conducted to predict the transport of conservative pollutants as in the case of a chemical spill accident. Generally speaking, when scenarios were applied, the arrival time and concentration of pollutants at each intake station was thus predicted.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3345-3350
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• 2014

We investigated to assess the relationships between the major nutrients and phytoplankton dynamics during the spring season in 2010 and 2011 at 23 stations in Jinhae Bay, Korea. The bay is divided into four different zones based on pollutant sources and geographical characteristics. Nutrient limitation (>80%) was significant in Zone II, which is located in central bay and is influenced by the water well mixed from outer bay. The limited nutrient was followed in Zone III and IV that was occupying between 17% and 83%. However, the low levels are being kept below 35% in Zone I, which is characterized by the semi-enclosed eutrophic area of Masan and Haegam bays. Based on the PCA (principle component analysis) analysis, the nitrogen (N) sources in 2010 were particularly dominant and it may be due to the water mixing and wastewater formed from bottom layers and sewage. In 2011, major nutrients including nitrogen, silicon and phosphorus were dominant in the bay and are supplied by the river discharge after rainfalls with low salinity conditions. In particular, the N nutrients being supplied in 2010 are correlated with pennate diatoms Pseudo-nitzchia spp. and is not related to the phytoplankton population densities in 2011. The present study suggests that N sources play an important role in the proliferation of diatom, and the rapid nutrient uptakes by them are potential nutrient limitation factors in the bay.

• Journal of Marine Life Science
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• v.5 no.2
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• pp.99-106
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• 2020

To investigate effect of variation in physiochemical conditions due to river discharge on phytoplankton, field surveys were conducted in the Seomjin and Yeongsan River estuaries from April to November 2016. The concentrations of DIN and DSi in Seomjin River estuary were gradually low as distance from upstream. On the other hands, the concentrations of DIN and DSi in Yeongsan River estuary were critically high at upstream, due to which is characterized as semi-enclosed eutrophic area. A total of 12 phytoplankton pigments were analyzed, and the distribution of each taxa was investigated using indicator for each phytoplankton taxa. Fucoxanthin, an indicator pigment of diatoms, showed an average of 0.61±1.00 ㎍ l^-1 and 0.76±1.22 ㎍ l^-1 in the Seomjin and Yeongsan River estuaries, respectively. Concentration of fucoxanthin was more than twice that of other pigments except chlorophyll a., indicating that diatoms were dominant taxa. Peridinin, an indicator pigment of dinoflagellate, showed some similar tendency to the microscopic observation, but mismatch results were also present, indicating a technical limitation of pigment analysis. Chlorophyll b, alloxanthin, and zeaxanthin, which are indicator pigments of green algae, cryptomonads, and cyanobacteria, were detected in both estuaries even though those taxa were not detected in microscopic observation. This indicates that the two estuaries were affected by freshwater species. Here, we can suggest that phytoplankton composition in estuary was directly influenced by the inflow from upstream. In particular, the phytoplankton population dynamics in Yeongsan River estuary was greatly associated with a large-scale artificial dyke, especially in summer rainy season. On the other hands, the seasonal and horizontal distribution of phytoplankton in Seomjin River estuary has changed along the salinity gradients and inflow-related changes.

• 한국사회정책
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• v.25 no.4
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• pp.233-263
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• 2018

This study sought to identify gender-specific mechanisms of increased suicide rates during economic crises in South Korea. In order to address research aims, we focused on two international economic crises: IMF financial crisis in 1997, and international recession in 2008. This study provides three main findings. First, different mechanisms increased suicide rates during the two economic crises. Particularly, the high level of unemployment raised suicide rates during the 1997 IMF while the high level of working poor in the 2008 recession. Second, suicidal risk patterns for men and women differed at each period. The 1997 crisis which mostly affected full-time permanent workers had had relatively greater impacts on men suicide, whereas the 2008 crisis which affected precarious workers had done on women suicide. Finally, our finding indicated that these gender-specific risk patterns had been derived from the gendered labour market and male-friendly social policy. Placing women at the periphery of the labor market and using them as a buffer in times of crisis, governments failed to protect them from their economic difficulties. Suicide is fundamental and important public health and social problems. These findings suggest that the national suicide prevention strategy should pay attention to the social determinants of suicide through gendered as well as population health perspectives.