• Journal of the Korean earth science society
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• v.33 no.4
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• pp.360-375
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• 2012

The purpose of this study was to compare 10th grade students' understanding of concepts about the plates' motions depending on the different spatial ability. Based on previous studies and literature reviews, two instruments were selected and used in this study. The Spatial Perception Test developed in Korean Testing Center was applied to measure students' spatial ability. Another instrument for testing students' understandings of plates' motions consists of a total of 10 items. The instruments were distributed to 118 students who were 10th graders in metropolitan city. The results are as follows: First, a correlation coefficient between conceptual understanding of plates' motions and spatial ability was r=0.439 (p<.01). It indicates that conceptual plates' motions and spatial ability have a moderate relationship. The students were divided into two groups (high and low) by spatial ability. The independent t-test was performed and reveals that the statistically significant difference between high and low groups. On the other hand, the 6 students (3 higher spatial ability students and 3 lowers) were selected and interviewed individually to find the differences in their understanding of the concept of plates' motions. The findings from interviews indicate that most students recognized about concepts of trench and ocean ridge, a rise and drop of the mantle, and divergent and convergent boundaries. However, students had misconceptions about section of trench and ocean ridge. In addition, the students who had higher spatial ability knew the more proper concepts about the creation and extinction of plate, crustal movements, and bottom of the ocean extension, whereas the students who had the lower spatial ability had misconceptions.

• Journal of Wetlands Research
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• v.17 no.3
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• pp.293-302
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• 2015

This study investigated sediment oxygen consumption rates and geochemical characteristics of sediment in hypoxic area of the Gamak Bay based on the chamber experiments and geochemical analyses. The organic carbon contents of surface sediment in the Gamak Bay showed that the inner bay area has higher organic carbon content than those of the outer bay. They toward the outer bay, contents dropped off. The vertical profiles of calcium carbonate ($CaCO_3$) content at piston core sediment assumed that the hypoxia have been frequently occurred during past century in the northern inner bay. The benthic chamber experiments were conducted in February, May, August and November 2010, 2011 in the hypoxic area of the Gamak Bay. In the sediment incubation experiment with chamber at site C3 in the northern inner bay and site C17 in the southern outer bay, the sediment oxygen consumption rate ranged from $3.98mmol\;m^{-2}d^{-1}$ to $12.43mmol\;m^{-2}d^{-1}$ and $3.28mmol\;m^{-2}d^{-1}$ to $8.18mmol\;m^{-2}d^{-1}$, respectively. When the oxygen was completely depleted, the toxic hydrogen sulfide was released with $1.38mmol\;m^{-2}d^{-1}$ and $1.3mmol\;m^{-2}d^{-1}$, respectively.

• ALGAE
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• v.31 no.3
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• pp.277-287
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• 2016

Five fractions separated from Nannochloropsis oculata using solvent-solvent partition chromatography of 80% methanolic extract of N. oculata (NOM) followed by the open silica column chromatography of its hexane fraction (NOMH) for the anti-inflammatory on RAW 264.7 cells and anti-cancer activities on HL-60, A-549, HEP-3B, HCT-116, and SW-480 cancer cells. All the five fractions showed potential anti-inflammatory activities against lipopolysaccharide-stimulated RAW 264.7 macrophages cells with IC₅₀ values less than 6.25 μg mL⁻¹. Moreover, 90% n-hexane column elution of NOMH (NOMH90) down-regulated lipopolysaccharide-stimulated protein levels of inducible nitric oxide synthase and cyclooxygenase-2. Furthermore, NOMH90 showed marked cytotoxic effect on the HL-60 cells with IC₅₀ value of 23.58 ± 0.09 μg mL⁻¹. In addition, Hoechst 33342 cell permeable dye used to visualize the apoptosis nucleus and cell cycle analysis measured Sub-G1 DNA contents to confirm reduction of the cell viability in NOMH90 treated cells due to induction of apoptosis in HL60. These results are quite related to the phytosterol contents of the NOMH fractions and the results suggest N. oculata extracts might be useful as potential sources of natural anti-inflammatory and anti-cancer compounds. In conclusion, the sterol content in N. oculata might provide a promising role in future medicines in anti-inflammatory and anti-cancer.

• Management & Information Systems Review
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• v.38 no.3
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• pp.151-170
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• 2019

This study deals with the rent-seeking behavior that exist in cultural voucher from the viewpoint of culture and arts management. Art organizations open to consumers, producers and governments of the arts are dependent on the internal and external influence of an open system. Researcher has found rent-seeking in the course of introducing policies and legalization of the cultural voucher business which has been promoted in the direction of democratization of culture or cultural democracy. Cultural voucher business is a legal term. Although the government has increased the budget or tried to change the policies of the cultural voucher business, the implementation of the cultural voucher business has been opposed to the diversity of consumption and equity as the consumption of genre and the concentration of the capital region have increased. These results were structurally related to the process of legalization and rent-seeking behavior in bureaucracy. This study reaffirms that the efficient operation standard of the cultural voucher business is a balance between the choice of the beneficiary, the competition of the supplier, and access to the cultural voucher. And the theory of rent-seeking was applied as a criterion to analyze this balance. Thus, it is suggested that the criteria of evaluation and improvement to check the conservativeness of bureaucrats are needed to establish a legal system applied to the purpose of 'cultural democracy' and 'democratization of culture' ideology and to guarantee individual creativity and autonomy.

• Journal of the Korean earth science society
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• v.36 no.2
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• pp.139-157
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• 2015

We investigated the relative errors of satellite-observed Surface Skin Temperature (SST) data caused by sea ice in the northern hemispheric ocean ($30-90^{\circ}N$) during April 16-24, 2003-2014 by intercomparing MODerate Resolution Imaging Spectroradiometer (MODIS) Ice Surface Temperature (IST) data with two types of Atmospheric Infrared Sounder (AIRS) SST data including one with the AIRS/Advanced Microwave Sounding Unit-A (AMSU) and the other with 'AIRS only'. The MODIS temperatures, compared to the AIRS/AMSU, were systematically up to ~1.6 K high near the sea ice boundaries but up to ~2 K low in the sea ice regions. The main reason of the difference of skin temperatures is that the MODIS algorithm used infrared channels for the sea ice detection (i.e., surface classification), while microwave channels were additionally utilized in the AIRS/AMSU. The 'AIRS only' algorithm has been developed from NASA's Goddard Space Flight Center (NASA/GSFC) to prepare for the degradation of AMSU-A by revising part of the AIRS/AMSU algorithm. The SST of 'AIRS only' compared to AIRS/AMSU showed a bias of 0.13 K with RMSE of 0.55 K over the $30-90^{\circ}N$ region. The difference between AIRS/AMSU and 'AIRS only' was larger over the sea ice boundary than in other regions because the 'AIRS only' algorithm utilized the GCM temperature product (NOAA Global Forecast System) over seasonally-varying frozen oceans instead of the AMSU microwave data. Three kinds of the skin temperatures consistently showed significant warming trends ($0.23-0.28Kyr^{-1}$) in the latitude band of $70-80^{\circ}N$. The systematic disagreement among the skin temperatures could affect the discrepancies of their trends in the same direction of either warming or cooling.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.128-139
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• 2022

This study aimed to investigate the tectonic setting of the volcanic edifice at Mt. Baekdu by analyzing petrochemical characteristics of Holocene felsic volcanic rocks distributed in the Baekdusan stratovolcano edifice and summit of the Cheonji caldera rim, as well as Pleistocene mafic rocks of the Gaema lava plateau and Changbaishan shield volcano edifice. During the early eruption phases, mafic eruption materials, with composition ranging from alkali basalt to trachybasalt, or from subalkaline (tholeiitic) basalt to basaltic andesite formed the Gaema lava plateau and Changbaishan shield volcanic edifice, whereas the Baekdusan stratovolcano edifice and Holocene tephra deposits near the summit of the Cheonji caldera comprises trachytic and rhyolitic compositions. Analysis results revealed bimodal compositions with a lack of 54-62 SiO₂, between the felsic and mafic volcanic rocks. This suggested that magmatic processes occurred at the locations of extensional tectonic settings in the crust. Mafic volcanic rocks were plotted in the field of within-plate volcanic zones or between within-plate alkaline and tholeiite zones on the tectonic discrimination diagram, and it was in good agreement with the results of the TAS diagram. Felsic volcanic rocks were plotted in the field of within-plate granite tectonic settings on discrimination diagrams of granitic rocks. None of the results were plotted in the field of arc islands or continental margin arcs. The primitive mantle-normalized spider diagram did not show negative (-) anomalies of Nb and Ti, which are distinctive characteristics of subduction-related volcanic rocks, but exhibited similar patterns of ocean island basalt. Trace element compositions showed no evidence of, magmatic processes related to subduction zones, indicating that the magmatic processes forming the Baekdusan volcanic field occurred in an intraplate environment. The distribution of shallow earthquakes in this region supports the results. The volcanic rocks of the Baekdusan volcanic field are interpreted as the result of intraplate volcanism originating from the upwelling of mantle material during the Cenozoic era.

• Journal of Fisheries and Marine Sciences Education
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• v.4 no.1
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• pp.30-46
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• 1992

Korea's first exploratory tuna fishing was done with a used longliner in 1957. Then the commercial fishing has been made steady headway since the 1960's and grown up to one of major tuna fishing countries in 1970's. The tuna fishing aimed primarily at acquiring foreign currency, then tuna was exported directly from the overseas fishing base. Tuna, however, has been gradually favored by Koreans as high-proteined foods according to the growth of GNP since the 1970's. In 1980, the canned tuna began to be produced and sold at home. And so the demand of raw tuna for cannaries has steeply increased not only for home but also for abroad, and stimulated the development of tuna purse seine fishery. The author carried out a study on the development of tuna purse seine fishery in Korea and countries concerned-the United States and Japan-because it is recognized to be significant for the further development of this fishery. Just as purse seining was originated in the United States, so tuna purse seining was also pioneered by Californian fishermen in the west coastal waters of the United States (Eastern Pacific Ocean). They started to produce the canned tuna in the early 1900's, and the demand for raw tuna began to be increased rapidly. In those days, tuna was mostly caught by pole-and-line, but the catch amount was far away from the demand. To satisfy this demand, they began to try out fishing tuna by the use of purse seine which had been born in the eastern waters in the 1820's and applied to catch white fishes in the western waters of the United States in those days. Even though their trial was technically successful through severe trial and error, a new problem was raised on the management of tuna resource and the preservation of porpoise which was occassionally caught with tuna. Then the Inter-American Tropical Tuna Commission (IATTC) was established by countries neighboring to the United States in 1950 and they set up the Commission's Yellowfin Regulatory Area (CYRA) and regulated the annual quota for yellowfin. Then, American owners tried to send their seiners to the Western African waters to expand the fishing ground in 1967 and to the Centeral-Western Pacfic in 1974, and the fishing ground was widely expanded. The number of the United States' purse seiners amounted to about 150 in 1980, but the enthusiasm was gradually cooled thereafter and the number of seiner was decreased to 67 in 1986. The landing of tuna by purse seiners in the United States after 1980 maintains 200 thousands M/T or so with a little increase despite the decreasing of domestic seiners. This shows that the landing by foreign seiners are increasing, compared with the landing by domestic seiners are decreasing. In Japan, even though purse seining was introduced in 1880, they had fished tuna by longline and pole-and -line until the tuna purse seining was introduced from the United States again. In the 1960's, Japanese tuna seiners made the exploratory fishing in the South-western Pacific and West African waters with a limited success. In 1971, the government-funded research center "JARMRAC" conducted the exploratory fishing which extended to the Central American waters, the Asia-Pacific Region and the South-western Pacific. It had also much difficulties, till they improved the fishing gear adaptable to the new fishing condition in the South-western Pacific. Japanese government has begun to licence 32 single seiners and 7 group seiners since 1980 and their standard has lasted up to now. The catch in the Pacific Islands Region amounted to 160 thousands M/T in 1986. Korea's tuna purse seine fishery was originated in 1971 by Jedong Industrial Co., Ltd. with three used tuna purse seiners purchased from the United States, and they began to fish in the Eastern Pacific, but failed owing to the superannuation of vessel and the infancy of fishing technique. The second challenge was done by Dongwon Industrial Co., Ltd. in 1979, with one used seiner purchased from the United States, and started to fish in the Eastern Pacific. Even though the first trial was almost unsuccessful but they could obtain the noticeable success by removing the vessel to the South-western Pacific in 1980. This success stimulated the Korean entherprisers to take part in this fishery, and the number of Korean tuna purse seiners has been increased rapidly in accordance with the increased demand for raw tuna. The number of vessels actually at work amounted to 36 in 1990 and they operate in the South-western Pacific. The annual catch of tuna by purse seiners amounted to 170 thousands M/T in 1990 and ranked to one of the major tuna purse seining countries in the world.