• Journal of the Korean association of regional geographers
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• v.2 no.2
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• pp.219-231
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• 1996

The aim here is to analyse the system of description of GIS in all of the high school textbooks passed with the official approval, to find the degree to which teachers understand about GIS, and to consider the present condition of GIS instruction. Most of the authors of textbooks generally underestimate importance of GIS, and there is difference among their awareness. In the system of description of GIS, there are only a few kinds of textbooks in which explanation of GIS is made coherently from the purpose of instruction aim through the chapter summary and to overall test in both of the Korean Geography and the World Geography. This trend is due to the degree of distribution of the GIS specialists in writing a textbook while the other texts books shows just a brief introduction of GIS concept. Although there is the limit for teachers to study how to teach GIS due to its very technological aspect as well as few previous training and teacher's guide. Thus it is evident that about a half of teachers who responded taught high school students without a knowledge on GIS, and a few of them even never referred to that concept. These facts may negatively affect the status of a geography in the society of information. For the solution of these issues, it is considered how to repair the description system and its contents. Besides, the variation among textbooks is reduced at the further revision of the 7th curriculum. And the printed matters of GIS are sufficiently provided for the teachers to use as their teaching aids. It is desirable that the GIS instruction models should be further developed for college education, and the programs for the on-the-job teachers training should be arranged. Besides, the previous training for the on-the-job teachers should be achieved more practically with enough time before the revision of curriculum.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.343-348
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• 2008

To investigate the effects of incorporation of green manures (GM) into a sandy loam soil on growth, yield, and nutrient uptake of tomato (Lycoperiscon esculentum Mill.) and nutrient balances (input minus offtake of nutrients), five tomato production systems were compared under the condition of plastic film house: 1) a no input system (no additional amendment or inputs, 0-To-0-To); 2) a conventional system (application of N-P-K chemical fertilizers, Cf-To-Cf-To); 3) a leguminous GM-containing system (hairy vetch-tomato-soybean-tomato, Hv-To-Sb-To); 4) a graminaceous GM-containing system (rye-tomato-sudan grass-tomato, Ry-To-Sd-To); and 5) system mixed with leguminous and graminaceous GMs (rye-tomatosoybean- tomato, Ry-To-Sb-To). Here, hairy vetch and rye were cultivated as winter cover crops during late $Dec{\sim}late$ Feb and soybean and sudan grass were cultivated as summer cover crops during late $Jun{\sim}mid$ Aug. All of them cut before tomato planting and then incorporated into soil. Biomass of GMs was greater in summer season than that of winter season. Nitrogen amount fixed by a leguminous plants was about $126\;kg\;ha^{-1}$ per a cropping season, corresponding to 60% N level needed for tomato production, which was comparable to 50 and $96\;kg\;ha^{-1}$ fixed by rye and sudan grass. As a result, tomato yield of Hv-To-Sb-To system (legume GM treatment) was similar to Cf-To-Cf-To (conventional), but that in Ry-To-Sd-To system (graminaceous GM treatment) was not attained to a half level of conventional treatment. Nutrient budgets for N, P and K on the conventional farm were balanced or somewhat positive exception for minus-balanced K. Ry-To-Sd-To system showed a positive N, P and K budgets due to the depressed growth of tomato which is caused by high C/N ratio and low N-fixing capacity of the GMs. Inversely, those of Hv-To-Sb-To system were negative in all of N, P and K budgets because of increased growth and yield of tomato with high nitrogen-supplying capacity as well as low C/N ratio of leguminous GM. In conclusion, although conventional cultivation has an advantage in relation to N, P and K nutrient budgets rather than GM-incorporated systems, a leguminous GMs could be recommended as nitrogen reservoir and soil amendment because the yield of tomato between use of leguminous GM and conventional cultivation was not only significantly difference, but also GMs commonly reduce nutrient loss and improve microbial communities.

• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.43-49
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• 2017

BACKGROUND: Greenhouse crops are one of agricultural products consumed largely in Korea. Cucumber is a typical example as main vegetables of greenhouse crops. Thus, pesticide residue analysis is an important requirement to guarantee pesticide safety of cucumber. This work was aim to investigate the residues of penthiopyrad and pyriofenone in cucumber after harvest. METHODS AND RESULTS: Cucumber was subjected to treat with penthiopyrad and pyriofenone at a level of recommended dose 0, 1, 2, 3, 5, 7 and 10 days before harvest under greenhouse conditions. The samples were extracted with organic solvent by using a homogenizer and purified on solid phase cartridge column followed by LC-MS/MS analysis. The recovery levels of penthiopyrad and pyriofenoneranged from approximately 81 to 93% with the method limit of 0.005 mg/kg and coefficient of variation less than 10%. Penthiopyrad and pyriofenone were detected at a level less than maximum residue limit in cucumber at 10 days before. The half-lives of penthiopyrad and pyriofenone were determined to 2.4 ~ 2.6 days. CONCLUSION: Penthiopyrad and pyriofenone are suggested to use in cucumber 10 days before harvest to reach their levels less than maximum residue limit.

• Journal of Environmental Impact Assessment
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• v.26 no.6
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• pp.553-562
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• 2017

In these days, agricultural reservoirs are considered as a useful resource for recreational purposes, tour and cultural amenity for vicinity communities as well as irrigation water supply. However, many of the agricultural reservoirs are showing a eutrophic or hyper-eutrophic state and high level of organic contamination. In particular, about 44.7% of the aged agricultural reservoirs that constructed before 1945 exceed the water quality criteria for irrigational water use. In addition to external loading, internal nutrient loading from bottom sediment may play an important role in the nutrient budget of the aged reservoirs. The objectives of this study were to characterize variations of thermal structure of a shallow M reservoir (mean depth 1.7 m) and examine the potential of internal nutrient loading by continuous monitoring of vertical water temperature and dissolved oxygen (DO) concentration profiles in 2015 and 2016. The effect of internal loading on the total loading of the reservoir was evaluated by mass balance analysis. Results showed that a weak thermal stratification and a strong DO stratification were developed in the shallow M Reservoir. And, dynamic temporal variation in DO was observed at the bottom of the reservoir. Persistent hypoxic conditions (DO concentrations less than 2 mg/L) were established for 87 days and 98 days in 2015 and 2016, respectively, during the no-rainy summer periods. The DO concentrations intermittently increased during several events of atmospheric temperature drop and rainfall. According to the mass balance analysis, the amount of internal $PO_4-P$ loading from sediment to the overlying water were 37.9% and 39.7% of total loading during no-rainy season in 2015 and 2016, respectively on August when algae growth is enhanced with increasing water temperature. Consequently, supply of DO to the lower layer of the reservoir could be effective countermeasure to reduce nutrient release under the condition of persistent DO depletion in the bottom of the reservoir.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.1
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• pp.28-34
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• 2017

A new naked oat cultivar, 'Jungmo2005'(Avena nuda L.), was developed for food and forage use by National Institute of Crop Science, RDA in 2010. It was derived from a cross between $F_1$['Early80'/'Gwiri33'] and $F_1$['Early80'/'Gwiri23']. 'Early80', a covered oats, has early heading and high yielding, while 'Gwiri23' of covered type and 'Gwiri33' of naked type has early heading with large-size grain. 'Jungmo2005' has the characteristics of narrow and long leaves of pale green color, middle diameter culm of yellow color and medium grain of whitish yellow color. Cultivar 'Jungmo2005' had 2 days earlier heading date (May 9) than the check cultivar 'Seonyang' (May 11) in field condition. The 'Jungmo2005' showed better winter hardiness than that of the check cultivar, and similar to the check cultivar in respect to lodging resistance. The 'Jungmo2005' had 105 cm of culm length, 21.5 cm of spike length, 658 spikes per $m^2$, 82 grains per spike, 23.3 g of 1,000-grain weight, and 622 g of test weight. The grain yield of 'Jungmo2005' was averaged $3.38MT\;ha^{-1}$, which was 6% higher than that of the check. Average forage fresh and dry matter yield of 'Jungmo2005' harvested at milk-ripe stage were 44.8 and $12.6tone\;ha^{-1}$, respectively, compared with 47.5 and $12.5tone\;ha^{-1}$ of the check. The protein content of the 'Jungmo2005' was similar to the check (7.6% and 7.5%, respectively), while ADF (28.6%) and NDF (51.5%) were lower than the check (31.4% and 57.0%, respectively). TDN content and RFV were higher than those of the check (66.3%, 120.3 and 64.1, 105.2, respectively). 'Jungmo2005' is recommended for fall sowing cropping only in the south area where daily minimum mean temperatures are averaged higher than $-4^{\circ}C$ in January, and it should not be cultivated in mountain areas, where frost damages is likely to occur. The areas would do better only to sow in spring season.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.590-599
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• 2014

This study was conducted to compare the cold tolerance of seven ground cover species, Orostachys japonica, Sedum oryzifolium, S. kamtschaticum 'SG1', S. reflexum, S. rupestre 'Blue Spruce', S. spurium 'Green Mental', and S. takesimense, which have been used for green roof and wall systems in Korea. Plants were grown in 10-cm pots and 1 g of tissues at stem-end and crown of each species were kept under either light or dark condition, respectively. For cold tolerance tests, plants were initially left at $4^{\circ}C$ and linearly cooled to 0, -4, -8, -12, -16, and $-20^{\circ}C$ at $-2^{\circ}C{\cdot}h^{-1}$ rate. Low temperature injury and regrowth rates were visually evaluated and assessed by image analysis, respectively. The lethal temperature ($LT_{50}$) of plant species was determined using electrolyte leakage measurements. S. reflexum was the most cold tolerant, showing the most survival at $-16^{\circ}C$, whereas S. oryzifolium and S. takesimense showed low temperature injury at $-8^{\circ}C$. Similar results were found with electrolyte leakage measurements at the stem end. For each species, the crown (Mean $LT_{50}:\;-12.15^{\circ}C$) was more cold tolerant than the stem end (Mean $LT_{50}:\;-10.47^{\circ}C$). In conclusion, S. reflexum and S. rupestre 'Blue Spruce' are recommended for planting in the central region of Korea during late fall and early winter, as they were more cold tolerant and showed more vigorous regrowth than the other tested plant species.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.580-586
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• 2008

Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of linoleic acid with conjugated double bonds. These conjugated dienes were found to be responsible for many biological properties related to health. The objective of this study was to evaluate the production of cis-9, trans-11 CLA by Lactobacillus acidophilus isolated from breast-fed infants. Nine different cultures were tested for their ability to produce cis-9, trans-11 CLA from free linoleic acid in MRS broth and 8% reconstituted skim milk medium supplemented with linoleic acid at $37^{\circ}C$ for 48 hr. cis-9, trans-11 CLA was not detected or detected in very small amount when cell pellets of strains grown in MRS broth and 8% reconstituted skim milk supplemented with linoleic acid of $200{\mu}g/mL$. However, free cis-9, trans-11 CLA was produced in both media. It appeared that 8% reconstituted skim milk produced more cis-9, trans-11 CLA than MRS broth. L. acidophilus NB 203 and NB 209 produced more cis-9, trans-11 CLA than other tested cultures. The inhibitory effects of supplemented linoleic acid on the growth of L. acidophilus NB 203 and NB 209 were not detected up to $3,000{\mu}g/mL$ linoleic acid addition during the growth at $37^{\circ}C$ for 48 h. The production of cis-9, trans-11 CLA by these two L. acidophilus strains increased in the logarithmic growth phase until 24 hr incubation. Under this experimental condition, the best yield of CLA isomers for L. acidophilus NB 203 and NB 209 could be obtained from medium supplemented with $500{\mu}g/mL$ linoleic acid at $37^{\circ}C$ after 24 hr of incubation. These results indicate that the use of lactic acid bacteria producing free CLA in fermented dairy products may have potential health or nutritional benefits.

• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.463-470
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• 1995

Complete prelining of artificial vascular grafts with autologous endothelial cells may be one of the ideal solutions to obtain a nonthrombogenlc blood-contacting surface. To establish an intact endothelial cell monolayer on a prosthetic surface at the time of implantation,a sufficient number of endothelial cells and adequate propagation condition In cell culture are prerequisites. In this experimental study, endothelial cells from microvessels of adult human oriental adipose tissue were enzymatically harvested, and optimal culture conditions for proliferation of the endothelial cells in cell culture were examined. Human oriental adipose tissue was digested with collagenase and endothelial cells were separated from other stromal elements by mesh filtration method. Cultured cells were identified as endothelial cells by immunofluorescent staining for factor VIII-related antigen. Proliferation in usual 20% fetal bovine serum (FBS) medium or medium containing endothelial cell growth factor (ECGF)(5 ng/ml) and heparin (HEP)(1,000 units/ml) were compared,and the effects of adding compounds that increase intracellular cyclic adenosine monophosphate levels, that is,cholera toxin (CT)(1 $\mu\textrm{g}$/ml) and isobutylmethylxanthine (IBMX)(0.2 ml),were also analyzed. In total,following eight media groups were examined. 1) FBS medium + ECGF + HEP, 2) FBS medium + ECGF + HEP+CT, 3) FBS medium+ECGF+HEP+lBMX, 4) FBS medium+ECGF+HEP+CT+ IBMX, 5) FBSmedium, 6) FBS medium +CT, 7) FBS medium + IBMX, 8) FBS medium + CT + IBMX. It was shown that the medium containing ECGF + HEP with or without cholera toxin was most efficient in Stimulating cell proliferation. IBMX was considered to have antagonistic effect to ECGF. Among experimental groups without ECGF and HEP, the addition of cholera toxin and IBMX was shown to significantly potentiate cell proliferation. This results could provide a practical method for use of cultured human endothelial cells for endothelial cell seeding of cardiovascular prosthetic device, particularly in small-diameter vascular grafts.

• Journal of Life Science
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• v.27 no.7
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• pp.805-811
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• 2017

In the previous paper, we isolated a bacterium that can hydrolyze various organic materials from soybean paste, including cellulose, lipids, starch, and protein. The activity and chemical properties of the crude enzymes produced by the isolate Bacillus subtilis CK-2 were further investigated. Cellulase showed the highest activity at pH 5.0 and $55^{\circ}C$. The stability of cellulase was maintained within the ranges of pH 5.0~10.0 and $20{\sim}50^{\circ}C$. Cellulolytic enzymes were activated by a $Co^{2+}$ ion, demonstrating the highest activity at a 0.45%(w/v) concentration of $Co^{2+}$. The optimal conditions for amylase were pH 5.0 and $50^{\circ}C$. The activity of amylase was stable within the ranges of pH 4.0~5.0 and $20{\sim}50^{\circ}C$. The $Co^{2+}$ ion was also necessary for amylase activity, which was the highest at a 0.2%(w/v) concentration of $Co^{2+}$. The optimal pH and temperature conditions of protease were pH 8.0 and $50^{\circ}C$. The activity of protease was stable within the ranges of pH 7.0~8.5 and $20{\sim}50^{\circ}C$. Protease activity was catalyzed by $Mn^{2+}$, which was the highest at a 0.125%(w/v) concentration of $Mn^{2+}$. The isolate B. subtilis CK-2 demonstrated a high activity of autolysin. Based on these results, we identified and suggested the optimal pH, temperature, and metal ion concentration in the use of the hydrolytic enzymes of B. subtilis CK-2 for industrial purposes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.181-189
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• 1983

A study on the qualify changes of fish meat during drying and storage has been carried out with filefish meat. Filefish meat was dried in a forced air dryer at 40 and $55\%$ for 20 hours with an air velocity of 0.4 m/sec under different conditions of relative air humidities in the range of 10 to $50\%$. The dried fish meat was stored at $30^{\circ}C$ in chambers with constant relative humidities controlled by the use of conditioned air stream passing through the saturated salt solutions. The qualify of filefish meat was evaluated with the brown color densities developed by lipid oxidation and Maillard reaction. Changes of viable cell count during drying and storage were also discussed. The predominant reaction for the brown color developed during the study period was the lipid oxidation. The lipid oxidation rate during drying at constant temperature was appreciably affected by water activities at the drying surfaces of filefish meat during the falling drying rate period. The lipid oxidation rate was the slowest under the condition of the relative air humidity of around $30\%$. In samples stored at water activity of 0.33, the lipid oxidation rate was retarded remarkably in comparison with the samples with lower or higher water activities. The addition of $1\%$ table salt, $1.5\%$ D-sorbitol and $6\%$ sucrose slightly lowered the water activity with the slowest lipid oxidation rate. Such additives resulted the increase of the water soluble brown color densities, which seemed due to the increase of mobility of the water soluble substances by the result of the increase of equilibrium water content. Microflora of the samples immediately after drying consisted of ca. $30\%$ of coccus types, ca. $65\%$ of rod types and ca. $5\%$ of molds and yeasts. During the storage of the samples with a water activity of 0.76, the ratio of the coccus types to the total microflora was increased remarkably while that of the Gram negative non-spore rod types was decreased. The ratios of the Gram positive rod types, molds and yeasts during the storage were nearly constant.