• 한국해양학회지
• /
• v.30 no.4
• /
• pp.320-331
• /
• 1995

The closely spaced cores were analyzed to find detailed reconstruction of paleoenvironments and sealable changes along the Delaware Bay coast. Three areas, Kitts Hummock Beach mars, the St. Jones River marsh, and Bowers marsh near the St. Jones River's mouth, were chosen because these areas are compose of their own geomorphic characteristics and sea-level history. since significance of the stratigraphic correlations was to determine sedimentary fancies and paleoenvironments, multidisciplinary methods such as lithological description, grain-size analysis, organic/inorganic content, water content, mineral composition, botanical analysis, micropaleontological analysis, and /SUP 14/C datings were performed. Five major divisions of marsh environments were recognized in the stratigraphic sections: freshwater marsh, initialfreshwater marsh, slightly brackish marsh, brackish marsh, and salt marsh. Most of the lower part in the stratigraphic sections show freshwater marsh. On the top of this, either brackish marsh or tidal flat/tidal stream was recorded. The pro-Holocene sediments consist of sand, mud, and sandy mud, The pre-Holocene configuration played an important role for developing the Holocene Paleoenvironmental changes. The irregular configuration of the pre-Holocene sediments consist of sand, mud, and sandy mud. The pre-Holocene configuration played an important role for developing the Holocene Paleoenvironmental changes. The irregular configuration of the pre-Holocene surface within short distances permitted the concurrent development of variable environments such as freshwater marsh, brackish marsh or salt marsh at similar elevations. The freshwater marsh in this case was formed in the areas of isolation, so saline-water cannot encroach upon these areas. This complex development of paleoenvironments leads to a difficulty in stratigraphic correlation and interpretation of local relative sea-level changes. The deposition of subsurface sediments was affected by sediment supply, compaction, fluvial activity, biological competition, local tectonics and isostacy, climate and local relative sea-level changes. It was interpreted that the positions in the changes from freshwater environments to brackish environments or ice versa are the turning points of transgressions and regressions. Therefore, multiple transgressions and regressions were identified in the stratigraphic sections of the study area.

• Applied Biological Chemistry
• /
• v.45 no.2
• /
• pp.84-91
• /
• 2002

If contaminated river water is sprayed over the floodplain, organic matter and nitrogen would be removed by microbial processes in the rhizosphere of vegetation during the filtration through soil. In this study we tested the organic matter and nitrogen removal from contaminated river water by the floodplain filtration. Model system of floodplain was constructed using a PVC pipe (15 cm i.d. ${\times}$ 150 cm L) which was packed with a loamy sand soil collected from a floodplain in Nakdong river. The model system was instrumented with soil solution samplers and gas samplers. A river water collected from Omogcheon in Kyongsan was sprayed from top of the model system at three different rates. The concentration of organic matter, DO, $NO_3^-$, $NO_2^-$, $NH_4^+$, $N_2$ and $N_2O$, and redox potential were measured as a function of soil depth for 24 days after the system reached a steady state. When river water was sprayed at the rates of 40.8 and 68.0 $l/m^2/day$, a significant reductive condition for denitrification was developed at below 5-cm depth of the soil. When the water reached at 90-cm depth of the soil, COD and concentration of inorganic nitrogen were lowered, on an average, from 18.7 to 5 mg/l and from 2.7 to 0.4 mg/l, respectively. $N_2$ comprised most of the N gas evolved from denitrification and $N_2O$ concentrations emitted at the surface of soil were less than 1 {\mu}l/l. The effective removal of organic matter and nitrogen by the filtration in the model system of floodplain demonstrates that the native floodplains, which include rhizosphere of vegetation at the top soil, could be more effective in the treatment of contaminated river waters and other industrial waste waters containing high concentration of organic matter and nitrogen.

• Journal of the Korean Geographical Society
• /
• v.31 no.2
• /
• pp.160-197
• /
• 1996

The purpose of this study is to review research trends and issues of economic geography in Korea for the last fifty years by sub-fields of agricultural geography, industrial geography, commercial and service geography, and transportation geography. Research in Korean economic geography has progressed significantly in terms of the scope and the number of papers published during the last a half a century. Agricultural geography was a leading field of economic geography in Korea before mid-1970s. Since the mid-1970s, however, agricultural geography has turned over the leading role in economic geography to industrial geography. Classification and structure of agricultural region has been the most popular research theme in Korea, even though diverse topics has been dealt in the research of agricultulal geography in Korea during the last fifty years. In recent years, emphasis is given to study on the dynamics of agricultural region and regional differentiation of part-time farming. It is suggested that the future issues of research in agricultural geography in Korea are agricultural restructuring and changes in agricultural space under the WTO system, changes in rural area and agricultural region with the progress of informatization, changes in agricultural structures and rural society by the increase of part-time farming, governments agricultulal policy and its impacts, competitive advantages of Korean agricultulal products, and environmental impacts of agricultural restructuring. Research in industrial geography has remarkably progressed since the 1980s. Locational changes, regional industrial structure and formation of industrial region were the major topics of interest in the research of industrial geography in Korea before 1980. Since the early 1980s, in addition to the topics which were interested in before 1980, changes of industrial organization and industrial location, changes of production systems and industrial space development of high technology industries and science parks, industrial restructuring and regional economy, foreign direct investments, industrial linkages and industrial districts, and industrial policy and regional development have been the major research themes of industrial geography in Korea. Considerable number of papers has been published both in Korean journals and in foreign journals during this period. Considering global changes in the organization of industrial space, future research should be more focused on firms strategy for regaining competitive advantages, local and global perspectives of industry, industry and environmental changes, in addition to the topics which have been dealt in recent years. Research in commercial and service geography and transportation geography was negligible in Korea before the late 1970s. These two sub-fields in economic geography have begun to develop since 1980s. Periodic markets, structure of commercial area, and distribution of products were the major topics of interest in the 1980s in the commercial and service geography in Korea. In the 1990s, however reserch in producer services has been active with growth of producer services in Korean economy. It is suggested that regional changes with progress of informatization and technology, changes of international trade and regional changes, development of efficient distribution system, role of producer services in regional development, and network of producer services are the major issues to be studied in the future in the field of commercial and service geography in Korea. Commuting, distribution of products, and transportation networks have been the major topics of research in transportation geography in Korea. Diverse quantitative techniques have been applied in the most of the researches in transportation geography. It is required that future studies in transportation geography should also focus on societal and behavioral issues, policy issues regional impacts of new transportation facilities, an analysis of transportation system at the global or international level. Since the 1980s economic geography in Korea has considerably progressed with publication of papers and books. The progress can be regarded as successful in quantitative aspect, but not in quantitative aspects. For the development of Korean economic geography in both quantitative and qualitative aspects, it is necessary to promote international collaborative researches and interdisciplinary cooperations. Attention should also be given to the research on changes in competitive advantages and economic restructuring, changes of economic space with the development of high technology and the progress of informatization. economic development and culture. and foreign regional studies.

• Journal of The Korean Association For Science Education
• /
• v.36 no.4
• /
• pp.591-606
• /
• 2016

The purpose of this study is to develop the argumentation program to build scientific concepts on natural selection for science-gifted elementary students and to know how to implement this program. For this study, nine key concepts about natural selection such as the overproduction of offspring, limited resources, population stability, competition, variation, heredity of variation, differential survival, change of the population and speciation were selected through the literature study. The programs were developed by learning cycle instructional model. Argument writings and discourses have been collected, analyzed and compared before and after the program. Two questionnaires to compare pre and post concept change consist of multiple choice questionnaire and open-ended response question were developed and applied to 19 science-gifted elementary students. Sufficiency of the explanation and conceptual quality of the explanation were used to assess the quality of their arguments before and after the program. Discourse and visual models collected from the highest and lowest group about score improvement were compared. The scores of the gifted statistically improved significantly in multiple choice questionnaire. Students' alternative conceptions about natural selection at the beginning of the program decreased and changed scientifically after the program. Visual models drawn by the students supported the results as well. This study asserts that elementary science-gifted students are able to explain evolutionary perspectives about organism change and use the key concepts of natural selection. The study means that evolutionary perspective is possible to be reflected in elementary science curriculum for the gifted.

• Journal of Aquaculture
• /
• v.11 no.4
• /
• pp.449-455
• /
• 1998

The small size food organism(under the size 150${\mu}m$) is needed as food for early stage of marine fish larvae of small mouse (e.g the group of grouper). This study was investigated to develop a method for copepod Apocyclops sp. culture in combination with the rotifer B. rachionus for stable culture of copepod species and harvest of various size food organisms. The culture conditions as temperature, salinity, culture volume, photo period, culture preiod and observation interval were 25${\circ}C$, 22ppt, 40ml, all dark except to observation time, 16 days and every two day during the experimental period, respectively. The Tetraselmis suecica was used as the food for the two testing orgtanisms. After every two day counting, theses two organisms were transferred to fresh culture tanks with Tetraselmis suecica of $7{\times}10^5$cells/ml. In the mixed culture of B. rotundiformis and A. sp., growth of rotifer was suppressed by mixed culture with A. sp. whereas the growth of copepod Apocyclops was promoted in the mixed culture with rotifer B. rotundiformis (the maximum density was 22 individuals/ml through the 16 culture days). Moreover, the number of copepod nauplius were promoted about 2 times in the mixed culture compared to the numbers in single species culture. With this combination culture, the havested two food organisms of variable sizes. This size variation of food organisms was useful tools for larval rearing of small mouse marine fish larvae and next step food organism size of post hatched larvae.

• Journal of Korea Port Economic Association
• /
• v.35 no.4
• /
• pp.1-16
• /
• 2019

The purpose of this study is to Analyze the problems that container shipping companies exist through the commercialization of container shipping for Non-Arctic countries and the opportunity factors for the transport of the Arctic shipping to improve cooperation cross-border relation Arctic policy and the use of transport. In order to design a hierarchy analysis method study model, four high and 17 low factors were extracted by designing a hierarchy analysis method study model based on results by prior study and in-depth interview. The first of the higher factors is the internal strength of assessing the value of the Arctic, the will and capabilities of the shipping companies in creating new markets with the vision and goals of the shipping companies. Second, the internal constraints associated with the shipping companies advance to the NSR mean the negative factors for the entry into the NSR and the internal weaknesses that cause the shipping companies capacity limitations. Third, the economic benefits from the use of NSR are external factor for shipping companies in cooperation with the future economic value of the Arctic and with respect to Arctic sea and Arctic advance and development from Arctic coastal countries. Finally, external pre-emptive tasks means to respond to use NSR by external restrictions on transport to prepare the possibility of severe weather conditions, the customs policy change of coastal countries.

• Korean Journal of Environment and Ecology
• /
• v.34 no.2
• /
• pp.157-169
• /
• 2020

The purpose of this study is to investigate the ecological characteristics and vegetation structures of Eurya japonica in Busan. As a result of the TWINSPAN and DCA analysis, 89 plots of 100㎡ each were divided into 3 communities: Quercus serrata-Pinus densiflora-E. japonica community, Pinus thunbergii-E. japonica community, and P. thunbergii-Camellia japonica community. Community I consisted of the Quercus serrata-Pinus densiflora-E. japonica which was mainly located in the high altitude inland. While Q. serrata and P. densiflora competed in the tree layer, the dominant species of the understory layer was E. japonica. Since Carpinus tschonoskii, one of the climax species, was distributed evenly from shrub to tree layers, it was likely that deciduous oak trees or Carpinus tschonoskii would become dominant species in community I. In community I, E. japonica was found in higher altitude than the other evergreen broad-leaved tree and was expected to maintain their tree vigor even if the vegetation structure is converted into the deciduous forest. Community II, the P. thunbergii-E. japonica community, was predicted to maintain its tree vigor unless there were unexpected disturbance factors. Community III, consisting of P. thunbergii-C. japonica and located in Dongbaek Island, was under artificial management. In community III, P. thunbergii was the only species in the tree layer, while C. japonica was predominant in the understory layer. E. japonica and various evergreen broad-leaved tree species were present in the understory layer and shrub layer, which were unmanaged areas. Therefore, it is expected that unless C. japonica is continuously managed, E. japonica is likely to become the dominant species. There were also various evergreen broad-leaved species, such as Machilus thunbergii and Pittosporum tobira, present in the shrub layer. If the temperature continues to rise, the habitat is expected to become evergreen broad-leaved forests in the future as P. thunbergii community declines. The result of Pearson's correlation coefficient analysis of E. japonica and species appearing in 89 plots showed that 9 species were had a statistically significant relationship (p<0.05). Four species, including P. tobira and Q. dentata, had a positive correlation. Five species had a negative correlation, and C. japonica, which had the same ecological position as E. japonica, showed the most negative correlation at -0.384.

• Journal of Life Science
• /
• v.25 no.7
• /
• pp.786-794
• /
• 2015

To identify nutritional and therapeutic properties of the new Korean red waxy sorghum cultivar ‘Hwanggeumchalsusu (HGC)’, we assayed the antioxidative effects and neuraminidase inhibitory activity. A methanol and 70% ethanol extract of HGC exhibited strong antioxidative effects (IC₅₀ values of 83.2±2.7 for DPPH) and 85.6±2.4 μg/ml for ABTS) and neuraminidase (ND) inhibitory activity (IC₅₀ values of 1.8±0.1 from extracted with methanol and 3.4±0.1 μg/ml from extracted with 70% ethanol) compared with that of the control, noncolored sorghum cultivar ‘Huinchalsusu (HC)’ (IC₅₀> 200 μg/ml). We isolated nine polyphenols, Gallic acid (1), Protocatecuic acid (2), p-Hydroxy benzoic acid (3), Vanillic acid (4), Caffeic acid (5), Ferulic acid (6), Luteolinidin (7), Apigeninidin (8), Luteolin (9), from the HGC - methanol extract, to determine whether they were the active components Luteolinidin of one kind of polyphenols from the HGC, exhibited significant antioxidative effects (IC₅₀ values of 10.9±0.5 μM for DPPH and 8.6 0.6 μM for ABTS) and neuraminidase (ND) inhibitory activity (IC₅₀ values of 26.3±0.6) showed noncompetitive inhibition model. The binding affinity of the ND inhibitors in molecular docking experiments correlated with their ND inhibitory activities. These results suggest that HGC may be utilized to serve as a potential effective antioxidant and inhibitor of ND.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.12
• /
• pp.1942-1947
• /
• 2014

Nutritional compositions of Korean traditional actinidia (Actinidia arguta) cultivars, such as Otumsense, Chiak, and Skinny green, were investigated as high value-added food substances. Among minerals, K content of three cultivars was the highest, and P, Ca, and Na contents were relatively higher than those of other minerals. Contents of essential amino acids were analyzed as follows: Otumsense (198.48 mg/100 g), Chiak (413.50 mg/100 g), and Skinny green (270.07 mg/100 g). Total amino acids of Chiak were the highest among the three cultivars, and major amino acids of the three cultivars were glutamic acid and aspartic acid. Analysis of fatty acids showed that major fatty acids were palmitic acid as a saturated fatted acid and ${\alpha}$-linoleic acid as an unsaturated fatty acid in the three cultivars. Glucose and fructose were major free sugar constituents in the three cultivars. Total free sugar content of Otumsense was relatively higher than others. Finally, niacin and vitamin $B_6$ of Skinny green (1.55 mg/100 g, 1.92 mg/100 g) were the highest among the cultivars. However, ${\beta}$-carotene as a vitamin A precursor ($3.82{\mu}g/100g$) and vitamin C as a natural antioxidant substance (47.18 mg/100 g) of Otumsense cultivar were the highest.

• Journal of Korean Society of Forest Science
• /
• v.85 no.1
• /
• pp.107-119
• /
• 1996

To understand vegetation changes along environmental gradients in the natural forests in the east side of the Cascade Range in Washington state, USA, line transects were used to sample six different forest environments in the Wenatchee National Forest in the north-facing and south-facing sites at 975, 1280 and 1700m elevation. Data were analyzed using ordination by detranded correspondence analysis. Pseudotsuga menziesii was found as one of the dominant species on all the six sites regardless of elevation or aspect, while Pinus ponderosa was dominant on south slopes only. Abies grandis and A. lasiocarpa were dominant species on north slopes at elevations of 1280 and 1700m, respectively. Moisture, as it related to aspect, was identified as one of the most important environmental gradients for explaining the variation of vegetation types. On north-facing slopes, compared to south-facing slopes, where moisture was not as limiting and canopies could grow denser, probably, elevation or competitive interaction was more important. Species diversity tended to decrease with increasing environmental severity, with south slopes having less diversity than north slopes due to extended water stress and harsher temperature extremes on south slopes. The age structure on north-facing and south-facing slopes was different. Light intensity, moisture and climate were different between these two slopes. Large scale disturbances(e.g., big fire or insects) were major causes in changing age structure. Younger trees showed a closer relationship between size and age than adult trees. DBH values of shade intolerant species in south-facing slope were bigger than those of north-facing slope, which suggested that aspect of stands be the most important factor for age and size.