• Horticultural Science & Technology
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• v.35 no.1
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• pp.121-130
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• 2017

This study was carried out to investigate a method for producing cultured virus - free ovules for breeding high - quality Citrus cultivars. Ovules from the immature fruits of three citrus cultivars native to Jeju (Dongjeongkyool, Cheongkyool, and Jikak) and two cultivars of Citrus unshiu Marc. (Miyagawa wase and Haryejosaeng) that were thought to be infected with Citrus tristeza virus (CTV) were cultured on MS2 medium (Murashige - Skoog [MS] basal medium containing $500mg{\cdot}L^{-1}$ malt extract, $50g{\cdot}L^{-1}$ sucrose, $1.0 mg{\cdot}L^{-1}$ kinetin, and $8g{\cdot}L^{-1}$ agar). After four weeks of culture, 10, 21, 13, 5, and 7 somatic embryos and 2, 4, 2, 4, and 5 white callus cells (surrounding green somatic embryos) were obtained from Dongjeongkyool, Cheongkyool, Jikak, Miyagawa wase, and Haryejosaeng, respectively. After six weeks of culture, somatic embryos were obtained from cultured cells grown on MT basal medium supplemented with malt extract ($500mg{\cdot}L^{-1}$), lactose ($70g{\cdot}L^{-1}$), and agar ($16g{\cdot}L^{-1}$). Over 60% of the somatic embryos from citrus cultivars native to Jeju developed into normal plants on MS basal medium supplemented with malt extract ($500mg{\cdot}L^{-1}$), sucrose ($50g{\cdot}L^{-1}$), and agar ($8g{\cdot}L^{-1}$) after 10 weeks of culture. Normal plants were regenerated from two Citrus unshiu Marc. cultivars on MT basal medium supplemented with sorbitol (1.0 M), galactose (1.0 M), $GA_3$ ($1.0mg{\cdot}L^{-1}$), and Gelrite ($3g{\cdot}L^{-1}$). The absence of virus in plants generated from cultured ovules was confirmed by RT - PCR and antigen - antibody reactions. Therefore, virus - free Citrus cells can be obtained for breeding high - quality citrus cultivars using the biotechnological technique evaluated in this study.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.6
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• pp.126-133
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• 2009

This study aimed to propose the base data to promote the green belt(thereafter GB) regulations and management in Korea. The research took the methods of analysis of citizen's official petitions to the once, of interviews and questionnaire to the of officials of Seoul Metropolitan City who is under the job of managing the GB. The conclusions were as follows. The officials did understand function and necessity of GB well. They especially, put the importance of the purpose of GB on the prevention of the environment of the city and prevention of concentration of population, They recognized that they suffered from the overloaded job on the management of GB in quantity and quality. The seriousness of illegal action of the change of land use, piling-up of materials and productions on the forbidden land, using exclusively of warehouses for agriculture as for commerce and enlarging the area of warehouse with application of leased land for agriculture instead of the agricultural land in law were detected in the officials' cognition. The officials proposed some ideas to prevent above mentioned illegal actions including forcing a person who did illegal actions to punish money to restore environment etc..

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.2
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• pp.86-102
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• 2012

For predictive flooded area susceptibility mapping, this study applied and verified probability model and the frequency ratio using a geographic information system (GIS) and frequency raio. Flooded areas were identified in the study area of field surveys, For predictive flooded area susceptibility mapping, this study applied and verified probability model and the frequency ratio using a geographic information system (GIS) and frequency raio. Flooded areas were identified in the study area of field surveys, and maps of the topography, geology, landcover and green infrastructure were constructed for a spatial database. The factors that influence flooded areas occurrence, such as slope gradient, slope, aspect and curvature of topography and distance from darinage, were calculated from the topographic database. Lithology and distance from fault were extracted and calculated from the geology database. The frequency ratio coefficient is overlaid for flooded areas susceptibility mapping as each factor's ratings. Then the flooded areas susceptibility map was verified and compared using the existing flooded areas. As the verification results, the frequency ratio model showed 82% in prediction accuracy. The method can be used to reduce hazards associated with flooded areas and to plan land use.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.23-23
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• 2009

GaN-based nitride semiconductors have attracted considerable attention in high-brightness light-emitting-diodes (LEDs) and laser diodes (LDs) covering from green to ultraviolet spectral range. LED and LD heterostructures are usually grown on (0001)-$Al_2O_3$. The large lattice mismatch between $Al_2O_3$ substrates and the GaN layers leads to a high density of defects(dislocations and stacking faults). Moreover, Ga and N atoms are arranged along the polar [0001] crystallographic direction, which leads to spontaneous polarization. In addition, in the InGaN/GaN MQWs heterostructures, stress applied along the same axis can also give rise to piezoelectric polarization. The total polarization, which is the sum of spontaneous and piezoelectric polarizations, is aligned along the [0001] direction of the wurtzite heterostructures. The change in the total polarization across the heterolayers results in high interface charge densities and spatial separation of the electron and hole wave functions, redshifting the photoluminescence peak and decreasing the peak intensity. The effect of polarization charges in the GaN-based heterostructures can be eliminated by growing along the non-polar [$11\bar{2}0$] (a-axis) or [$1\bar{1}00$] (m-axis) orientation instead of thecommonly used polar [0001] (c-axis). For non-polar GaN growth on non-polar substrates, the GaN films have high density of planar defects (basal stacking fault BSFs, prismatic stacking fault PSFs), because the SFs are formed on the basal plane (c-plane) due to their low formation energy. A significant reduction in defect density was recently achieved by applying blocking layer such as SiN, AlN, and AlGaN in non-polar GaN. In this work, we were performed systematic studies of the defects in the nonpolar GaN by conventional and high-resolution transmission electron microscopy.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.3
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• pp.145-150
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• 2007

This experiment was carried out to breed the cold-tolerant variety of Italian ryegrass (Lolium multiflorum Lam.) in Grassland and Forage Crops Division, National Institute of Animal Science, RDA, Cheonan from 1999 to 2005. New variety, 'Kospeed' is a diploid variety with green in leaf color, and has semi-erect and erect growth habit in late autumn and early spring, respectively. 'Kospeed' was on 1 May in heading date as a early-maturing variety. Also 'Kospeed' was wider by 0.2mm in flag leaf width, longer by 1cm in flag leaf length and shorter by 1cm in plant length than those of 'Florida 80', respectively. Stem width of 'Kospeed' was similar to that of 'Florida 80' and 'Hwasan 101'. Cold tolerance of 'Kospeed' was better than that of 'Florida 80'. Dry matter (DM) yield (13,257kg/ha) of 'Kospeed' was similar to that of 'Florida 80'. In vitro dry matter digestibility (IVDMD) and total digestible nutrient (TDN) of 'Kospeed' were 73.2% and 65.3% which are 2.1% and 1.7% higher than those of 'Florida 80', respectively. Acid detergent fiber(ADF) and neutral detergent fiber (NDF) of 'Kospeed' were 29.1% and 53.1% which are 2.1% and 2.3% lower than those of 'Florida 80', respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.1
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• pp.9-14
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• 2006

This experiment was carried out to breed the cold-tolerant variety of Italian ryegrass (Lolium multiflorum Lam.) at the Grassland and Forage Crops Division, National Livestock Research Institute, RDA at Suwon, Korea, from 1999 to 2005. The new variety 'Kogreen' is a diploid variety with a green leaf color and had semi-erect habit in late autumn and erect growth habit in early spring. The heading date of 'Kogreen' was on May 4, and for 'Florida 80' was May 2, both are considered as early-heading variety. 'Kogreen' was wider by 0.7mm in flag leaf width, longer by 2 cm in flag leaf length and shorter by 1cm in plant length than the control variety, Florida 80. Stem width of 'Kogreen' was similar to that of 'Florida 80' and 'Hwasan 101'. cold tolerance of 'Kogreen' was better than that of 'Florida 80'. Dry matter(DM) yield (12,884kg/ha) of 'Kogreen' was 3% less than that of 'Florida 80'. in vitro dry matter digestibility was 74.7% and total digestible nutrient was 65.1%, which are 3.6% and 1.5% higher than those of 'Florida 80', respectively. Acid detergent fiber and neutral detergent fiber of 'Kogreen' were 30.1% and 54.1% which are 1.9% and 1.3% lower than those of 'Florida 80', respectively.

• Nutrition Research and Practice
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• v.4 no.6
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• pp.486-491
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• 2010

Tight control of blood glucose is the most important strategy for the treatment of diabetes mellitus. Here, we investigated the beneficial effects of Welsh onion on fasting and postprandial hyperglycemia. Inhibitory activities of hot water extracts from the green stalk and white bulb, which are the edible portions of the Welsh onion, and the fibrous root extract against yeast ${\alpha}$-glucosidase were measured in vitro. To study the effects of Welsh onion on postprandial hyperglycemia, a starch solution (1 g/kg) with and without Welsh onion fibrous root extract (500 mg/kg) or acarbose (50 mg/kg) was administered to streptozotocin-induced diabetic rats after an overnight fast. Postprandial plasma glucose levels were measured and incremental areas under the response curve were calculated. To study the hypoglycemic effects of chronic feeding of Welsh onion, five-week-old db/db mice were fed an AIN-93G diet or a diet containing either Welsh onion fibrous root extract at 0.5% or acarbose at 0.05% for 7 weeks after 1 week of adaptation. Fasting plasma glucose and blood glycated hemoglobin were measured. Compared to the extract from the edible portions of Welsh onion, the fibrous root extract showed stronger inhibition against yeast ${\alpha}$-glucosidase, with an $IC_{50}$ of 239 ${\mu}g/mL$. Oral administration of Welsh onion fibrous root extract (500 mg/kg) and acarbose (50 mg/kg) significantly decreased incremental plasma glucose levels 30-120 min after oral ingestion of starch as well as the area under the postprandial glucose response curve, compared to the control group (P < 0.01). The plasma glucose and blood glycated hemoglobin levels of the Welsh onion group were significantly lower than those of the control group (P < 0.01), and were not significantly different from those fed acarbose. Thus, we conclude that the fibrous root of Welsh onion is effective in controlling hyperglycemia in animal models of diabetes mellitus.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.477-484
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• 2002

Ninety pre-puberal (6-7 months) female and 15 pre-puberal male Black Bengal goats were collected on the basis of their phenotypic characteristics from different parts of Bangladesh. Goats were reared under semi-intensive management, in permanent house. The animals were vaccinated against Peste Des Petits Ruminants (PPR), drenched with anthelmentics and deeped in 0.5% Melathion solution. They were allowed to graze 6-7 h along with supplemental concentrate and green forages. Concentrates were supplied either 200-300 g/d (low level feeding) or quantity that supply NRC (1981) recommended nutrient (high level of feeding). Different physiological, productive and reproductive characteristics of the breed were recorded. At noon (temperature=$95^{\circ}F$ and light intensity=60480 LUX) rectal temperature and respiration rate of adult male and female increased from 100.8 to $104.8^{\circ}F$ and 35 to 115 breath/min, indicated a heat stress situation. Young female attain puberty at an average age and weight of 7.2$\pm$0.18 months and 8.89$\pm$0.33 kg respectively. Mean age and weight at 1st kidding were 13.5$\pm$0.49 months and 15.3$\pm$0.44 kg respectively. It required 1.24-1.68 services per conception with an average gestation length of 146 days. At low level of feeding the postpartum estrus interval was 37$\pm$2.6 days, which reduced (p<0.05) with high feeding level to 21$\pm$6.9 days. Kidding interval also reduced (p<0.05) from 192 d at low feeding level to 177 d at high feeding level. On an average there were two kiddings/doe/year. Average litter sizes in the 1st, 2nd, 3rd and 4th parity were 1.29, 1.71, 1.87 and 2.17 respectively. Birth weights of male and female kids were 1.24 and 1.20 kg respectively, which increased (p<0.05) with better feeding. Although kid mortality was affected (p<0.05) by dam's weight at kidding, birth weight of kid, milk yield of dam, parity of kidding, season of birth, but pre-netal dam's nutrition found to be the most important factor. Kid mortality reduced from 35% at low level of feeding to 6.5% at high level of feeding of dam during gestation. Apparently, this was due to high (p<0.05) average daily milk yield (334 vs. 556 g/d) and heavier and stronger kid at birth at high feeding level.

• Journal of Sericultural and Entomological Science
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• v.29 no.1
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• pp.7-11
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• 1987

The influence of planting density, on the mulberry yield, had been studied for 5 years period since 1982. For this purpose, a hilly land (15$^{\circ}$) was selected and 5 planting density level (926, 1,667, 2,780 and 3,444 tree/10a) were used. Following results were obtained. 1. Vinyl mulching promoted 2 days earlier of green tip sprouting stage and 3 days earlier of shallow-bill stage, compared with the non-mulching. 2. It was shown that increase of the length of the branch with vinyl mulching and decrease of the mulching effect with the higher density of plants from, 2,780 tree/10a. 3. When the planting density was higher, length and width of leaf was decreased sharply, and chlorosis of the lower part of the branch was occured heavily. 4. With the higher planting density, number of branches per tree and average length of the branch was decreased. Number of shorter branch-normal branch ratio were increased. However, number of branches and total length of branch per area were shown opposite. 5. Yield of mulberry was increased for the peroid of 3 years after planting with the all the levels of planting density after that, yield increase was dully in 926 tree plot, and more dully in 1,677 trees plot, while decrease of the yield were showen with density of 2,780 and 3,444 trees plots. 6. The highest average yield for the 5 years were obtained from 2,780 trees plot, 46.6% higher than in 926 trees plot, followed 40% higher in 3,444 trees plot, and 29.9% higher in 1,667 trees plot. 7. Soil pH, organic matter, Ca and Mg decreased with cultivation, especially P2O5, pH, Ca and Mg in the density of more than 926 trees plot.

• The Korean Journal of Malacology
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• v.28 no.2
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• pp.175-185
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• 2012

To clarify reproductive ecology of the melania snail Semisulcospira coreana (v. Martens, 1886) in Bukhan River, gonad development, fatness, gonad index, sex ratio, first sexual maturity of population, monthly change of larvae number and developmental stages in brood pouches were investigated by six identification methods. As maturation progrsses, the sex of the snali can be distinguishable easily by color:: the ovary being blue-green and testis light yellow. The sex ratio of female to male individuals over 13.95 mm shell height was significantly different from 1:1 (${\chi}^2$ = 38.45, p < 0.05). The sex ratio of female to male individuals changed drastically according to the season, Based on the monthly variations of fatness, gonad index and histological analysis, spawning occurred twice a year (spring and autumn) and the mean size of matured eggs was $450{\mu}m$ in diameter. The monthly change of larval number in brood pouch showed also two distinct peaks in March and September during the year. The average number of larvae in brood pouches was 286 - 862 individuals. In this study, the number of larvae in the brood pouches were a minimum in December and a maximum in March (975 larvae). The biological minimum size (the size at 50% of group sexual maturity) of the melania snail was 13.95 mm in shell height in females and males. All females over 15 mm in shell height possesed brood pouches.