• Journal of the Economic Geographical Society of Korea
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• v.8 no.1
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• pp.91-105
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• 2005

The assessment (or the evaluation) of spatial disparity is the main concern for the study of spatial disparities or spatial inequalities. In order to evaluate the spatial disparity, the regional differences have to be counted quantitatively. Several measurements have been introduced for evaluating the development potentials of each region. Most of them are the composite indices of the socio-economic variables rather than the real potentials of the region. This study attempts to investigate the spatial disparity in Korea. For the purpose, the levels of opportunity potentials of the cities have been calculated by the Potential Model redefined by Lee(1995). The opportunity potentials have been calculated for the educational, cultural, medical service, environmental sectors, income, and consumption sectors, and the spatial patterns of various opportunity potentials have been analyzed. The spatial patterns of opportunity potentials show the severe concentration on the Metropolitan Seoul area through all sectors. The next level concentration appears at the other end of the Keuyng-Bu axis. And the cities relatively high opportunity potential values are distributed along the Keuyng-Bu axis. Remain parts of the country show quietly low opportunity potential values. In particular, the southern-west and the northern-east parts show relatively very low values. This pattern appears for all sectors except for the opportunity potential of the environmental sector. It means that the spatial disparity in Korea have been promoted and enhanced by the national development policies concentrated the investment on the large cities along the Keuyng-Bu axis during the last 40 years.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1690-1698
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• 2012

As alcohol use is one of the most important risk factors for injuries, this study was intended to clarify and evaluate any relationship between drinking patterns and the incidence rates/specific characteristics of injuries in adult populations, using a widely accepted tool, the Alcohol Use Disorders Identification Test (chronic alcohol drinking behaviors measurement, hereinafter the AUDIT) developed by the World Health Organization to help to assess the behaviors in a more accurate and reliable manner. This study used the data collected from the 2009 Korea National Health and Nutrition Examination Survey (KNHANES), in which 7,511 of 7,893 adult participants aged ${\geq}19$ years answered the questions about injuries, and excluding 104 non-respondents, 6,258 of participants in the questionnaire survey of drinking patterns were finally analyzed. The incidence rates and specific characteristics of injuries as classified by the AUDIT categories (i.e., body regions, types and mechanisms) were assessed and estimated in terms of their relative risk using t-test, ANOVA, and logistic regression. SPSS 19.0 statistical package software was employed for statistical analyses. These analyses indicate that the incidence rates of overall injuries were significantly higher in male respondents than in female respondents. The risks of alcohol use related injuries were 8.3 times higher in male respondents than in female ones. Regarding educational background, high school graduates showed the highest rates in the AUDIT with significant difference from the other groups. The married group and the group of respondents having monthly income estimated at KRW 2.01 to 3 million also showed the highest rates in the AUDIT compared to the other groups, indicating statistically significant difference. Significantly increased in problematic drinkers and those with alcohol dependence, the incidence rate of injuries body regions was 0.0371 in the head/neck, and with respect to the AUDIT and the mechanisms of external causes of injuries, transport accidents ranked first, followed by slippage, others, crash and fall. In regard to the classified types of injuries, it was statistically significant in others (e.g., laceration, contusion, addiction, or penetrating wound). In conclusion, the mechanisms of external causes of injuries as well as injuries attributed to alcohol use are very important, and a strategy is required to reduce such the injuries in the manner of decreasing the frequency of drinking after motivation by professional counsellors.

• Korean journal of applied entomology
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• v.59 no.1
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• pp.25-35
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• 2020

The striped fruit fly, Zeugodacus scutellata, is endemic in Korea, but it has been regarded as one of the serious quarantine pests throughout the world. Sterile insect release technique (SIT) has been used to eradicate quarantine fruit flies. This study developed a technique to generate sterile males and applied SIT to control Z. scutellata. First of all, the reproductive systems of Z. scutellata adults were examined with fluorescent microscope. Polytrophic ovaries comprises of around 100 follicles with developing oocytes. Each follicle contains an oocyte with several nurse cells and are surrounded with follicular epithelium. Oocyte development began at 10 days after adult emergence (DAE) and formed chorionated oocytes after 20 DAE. On the other hand, male testes were well developed just after adult emergence. The vas deferens was filled with motile sperms. To generate sterile males, different doses (0~1,000 Gy) doses of electron beam were irradiated to 3~5 days old pupae of Z. scutellata. When male pupae were irradiated with electron beam at 200 Gy, they developed and mated with females without any significant difference compared to untreated males. Although the untreated females mated with the 200 Gy-irradiated males laid eggs, no eggs did not hatch. The 200 Gy-irradiated males were then applied to untreated male and female flies in a density ratio of 1:9 (untreated males : treated males). The laid eggs suffered significant infertility. These results suggest that electron beam-irradiated pupae at 200 Gy resulted in male sterility and the resulting males would be applied to SIT.

• Journal of Gastric Cancer
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• v.5 no.4 s.20
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• pp.238-245
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• 2005

Purpose: Ghrelin, produced primarily in the gastrointestinal tract, including the stomach, has been reported to reflect nutritional status and to control homeostasis by influencing food intake and adiposity. The purpose of this study is to evaluate nutritional status, as well as plasma and gastric tissue ghrelin levels, in patients with gastric cancer who underwent a gastrectomy. Materials and Methods: Eighty patients were analyzed by the degree of weight loss $(weight\;loss{\geq}5%\;or\;<5%)$ and the extent of gastrectomy (subtotal or total gastrectomy). Blood samples were collected from all patients preoperatively and postoperatively especially at seven days. Gastric tissues, including tumor and normal tissues, were obtained from the resected stomach. levels of plasma and tissue ghrelin were measured with a commercial ELISA kit. Results: There were no significant differences in the clinical characteristics and ghrelin levels of plasma, gastric tumor tissue and normal tissue by the degree of weight loss. The ghrelin levels in plasma and tumor tissue showed no correlations with each other while the ghrelin level in tumor tissue was significantly lower than that in normal tissue. The degree of cellular differentiation also had an association with ghrelin production. A gastrectomy proved to decrease significantly plasma ghrelin levels, body mass index, and biochemical markers, regardless of the extent of gastric resection. Conclusion: These results show that gastric cancer affects the production of ghrelin in the gastric mucosa and that ghrelin is mainly produced in stomach even though it could be partially covered by endogenous ghrelin from other organs following a gastrectomy. However, we should further investigate which other factors have an impact on energy consumption, ghrelin secretion, and changes in ghrelin levels after a gastrectomy.

• Journal of Aquaculture
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• v.20 no.4
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• pp.278-288
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• 2007

Shrimp culture in Korea had been rapidly developed during 1990's and the production of farmed shrimp reached 3,268 mt from 2,605 ha in 2001. However the shrimp production decreased to 2,368 mt in 2004 because of the mass mortality due to outbreak of white spot syndrome virus (WSSV). WSSV which is one of the most serious threats associated with cultured shrimp around the world has given the economic damages to shrimp culture industry every year since it was found from the shrimp ponds in the west coast of the South Korea in 1993. Various polyculture technologies of shrimp with shellfish, finfish or seaweeds have been implemented to reduce economic damages by mass mortalities of shrimp. Among them, the polyculture of shrimp with carnivorous fish can suppress or delay the viral outbreak of shrimp ponds because the fish may selectively eat the moribund shrimps infected by virus. To determine the selective predatory effect of river puffer Takifugu obscures on WSSV infected shrimp, postlarvae of Litopenaeus vannamei and Fenneropenaeus chinensis. One-year old river puffers were stocked to four earthen ponds of $1,616-1,848\;m^2$ in surface area as followings: polyculture LvP, L. vannamei ($43.4/m^2$)+puffer ($0.22/m^2$); control Lv, L. vannamei ($46.9/m^2$); polyculture FcP, F. chinensis ($30.3/m^2$)+puffer ($0.25/m^2$); control Fc, F. chinensis ($24.6/m^2$). Ponds of control Fc and polyculture FcP had mass mortalities by WSSV outbreak on the $51^{st}$ and $57^{th}$ days of culture respectively. The shrimps of polyculture LvP and control Lv were harvested on the $95^{th}\;day$. Shrimp survival rates of polyculture LvP and control Lv were 32.4% and 18.2% respectively and shrimp productivity of polyculture LvP was 69.2% higher than that of control Lv. Concentration of nutrients (TAN, $NO_2-N$, $NO_3-N$) was maintained within optimal ranges for shrimp growth although that of polyculture ponds showed at least two times higher than that of control ponds. The results suggest that polyculture of L. vannamei with river puffer is higher than monoculture in survival rate and productivity. In addition, F. chinensis should be carefully cultured because this species shows much higher susceptibility to WSSV than L. vannamei.

• Horticultural Science & Technology
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• v.35 no.3
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• pp.344-360
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• 2017

Zoysiagrasses are important turf plants used for school playgrounds, parks, golf courses, and sports fields. The two most popular zoysiagrass species are Zoysia japonica and Zoysia sinica. These are widely distributed across different growing zones and are morphologically distinguishable from each other; however, it is phenotypically difficult to differentiate those that grow along the coastal line from those in beach area habitats. A combination of morphological and molecular approaches is desirable to efficiently identify these two plant cultivars. In this study, we used a rapid identification system based on DNA barcoding of the nrDNA-internal transcribed spacer (ITS) regions. The nrDNA-ITS regions of ITS1, 5.8S nrDNA, and ITS2 from Z. japonica, Z. sinica, Agrostis stolonifera, and Poa pratensis were DNA barcoded to classify these grasses according to their molecular identities. The nrDNA-ITS sequences of these species were found at 686 bp, 687 bp, 683 bp, and 681 bp, respectively. The size of ITS1 ranged from 248 to 249 bp, while ITS2 ranged from 270 to 274 bp. The 5.8S coding region ranged from 163 - 164bp. Between Z. japonica and Z. sinica, nineteen (2.8%) nucleotide sites were variable, and the G+C content of the ITS region ranged from 55.4 to 63.3%. Substitutions and insert/deletion (indel) sites in the nrDNA-ITS sequence of Z. japonica and Z. sinica were converted to cleaved amplified polymorphic sequence (CAPS) markers, and applied to the Zoysia grasses sampled to verify the presence of these markers. Among the 62 control and collected grass samples, we classified three groups: 36 Z. japonica, 22 Z. sinica, and 4 Z. japonica/Z. sinica hybrids. Morphological classification revealed only two groups; Z. japonica and Z. sinica. Our results suggest that used of the nrDNA-ITS barcode region and CAPS markers can be used to distinguish between Z. japonica and Z. sinica at the species level.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.109-116
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• 2002

The objective of this study was to know the qualities of soil and shallow groundwater in plastic film house fields around Central Part of Korea. The study was conducted at 11 sites in Suweon, Hwasung, Pyungtaek, Yongin and Chuncheon through May to August in 1999. Soil textures of plastic films house were mainly sandy loam or loam. Electric conductivity and organic matter content of surface soils mostly exceeded the critical levels for crop production. Average concentration of $NO_3-N$ in the sha]low groundwater was 19.1 mg/L, and it reached almost the limiting level of agricultural groundwater quality (20 mg/L). Moreover about 36% of survey sites exceeded the limiting level of agricultural groundwater quality. Sulfate concentrations also at some sites exceeded agricultural groundwater quality limit level (50 mg/L). Nitrate-N, one of the most important factors in the groundwater quality, had positive correlations with other ions in foundwater.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2189-2198
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• 2012

This study was designed to measure the difference in health-related quality of life (HRQOL) among social classes and explore the factors that may explain it. Study subjects were 7,992 Korean adults aged 20-69 from the 4th (2007-2009) Korea National Health and Nutrition Examination Surveys data. We described mean value of EQ-5D index as a HRQOL by class and performed hierarchical multiple regression analysis to find the factors. The result was as follows. In the distribution of EQ-5D index level among social classes, new middle class (class II) had the highest score (0.966 in men and 0.955 in women); upper and middle-upper class (class I) 0.965 in men and 0.936 in women; working class (class IV) 0.958 in men and 0.936 in women; old middle class (class III) 0.955 in men and 0.932 in women; low class (class VI) 0.941 in men and 0.908 in women; and rural self-management class (class V) the lowest score (0.918 in men and 0.866 in women). In men, chronic disease, job stress, education and income level were found to make the difference in the health-related quality of life among social classes; in women, those factors and health behavior explained the difference. In conclusion, the lower social class has lower HRQOL. Except for education and income level, chronic disease may be the major factor to explain the difference in the health-related quality of life among social classes.

• Journal of Aquaculture
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• v.22 no.1
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• pp.42-50
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• 2009

Shrimp farming which is entirely conducted in outdoor ponds in the west coast of Korea has been suffered from mass mortality due to viral epizootics. Intensive indoor shrimp culture under limited water exchange can solve these problems of outdoor ponds including viral transmission from environment, pollution due to discharge of rearing water, low productivity and limited culture period. In this study, juvenile L. vannamei (B.W. 0.08-0.09 g) was stocked with $3,000-5,455/m^3$ in density in four raceway tanks (two $12.9\;m^2$, two $18\;m^2$ tanks) and cultured for 42 days with 2.7-3.4% of daily water exchange. Results from four tanks showed FCR of 0.79-1.29, survival of 38.2-48.0%, and yields of $2.49-4.22\;kg/m^3$ which is consistent with 12-20 and 8-14 times higher than those of commercial shrimp hatchery and outdoor pond in Korea, respectively. Concentrations of total ammonia nitrogen in all four tanks were 1.11-1.42 ppm in mean level and did not exceed 6.0 ppm (0.096 ppm of $NH_3$) which is still acceptable levels for shrimp growth. During the culture trial, concentration of $NO_2$-N rapidly increased from stocking, resulting in mean concentration of 18.45-22.07 ppm. It also exceeded 10 ppm over four weeks and maintained at 35-45 ppm for four days in all tanks, accounting for low survival of shrimp due to long-term exposure to high concentration of $NO_2$-N. Nevertheless, the results with survival rate over 38% from raceways which experienced the extreme $NO_2$-N levels suggests that under "biofloc system" white shrimp can acclimate to high $NO_2$-N concentration to some degree.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.731-742
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• 2014

In the current study, we investigated effects of a combination of earthworm casting, environment-friendly by-product fertilizer, and cultivation soil of Gymnocalycium mihanovichii in a heavy fertilizing culture on diameter, height, numbers of tubercles, and chemical properties of soil thereby elucidating optimal mixture ratio for securing production as well as providing nutrients throughout cultivation period. The Gymnocalycium mihanovichii var 'Ihong', one of grafted cactus for export (Rootstock: 9 cm, Scion: $1.5{\times}1.3cm$ grafted cactus) was cultured in plastic houses of Agricultural Technology Center located in Naegok-dong, Seocho-gu, Seoul from June, 2013 through December, 2013. For the control group, a mixture of sand and fertilizer (50:50) was used as this ratio is widely utilized in farmhouses. In contrast, a variety mixtures of sand and earthworm casting that was produced with food wastes was compared; the mixture ratios were 80:20, 60:40, 40:60, 20:80, and 0:100 and pH for these mixtures were found to be similar each other (ranging between 7.1 and 7.4) which is in an appropriate range (pH 6.5-7.5) for cultivation of G. mihanovichii. The organic content was increasing along with increasing contents of earthworm casting ratio while it was lower than the treatment practice group (32-43 mg/kg vs. 55 mg/kg). The content of exchangeable cation was also increasing as the ratio of earthworm casting was elevated; although levels of $K^+$, $Na^+$, and $Mg^{2+}$ were lower than the treatment practice group, the level of $Ca^{2+}$ was higher ($9.1cmol^+/kg$ and $11.5-33.7cmol^+/kg$ in the treatment practice group and the earthworm casting group, respectively). Three months after grafting, diameters of G. mihanovichii were compared with the control group; consequently, there was a significant difference noted in between the earthworm casting group and the control group (31.39 mm vs. 32.46-37.59 mm). After 5 months, growth characteristics of G. mihanovichii were evaluated. Similarly, the diameter of G. mihanovichii was significantly increasing in the group with higher ratio of earthworm casting treatment (32.63 mm vs. 32.49-37.59 mm). The height of tubercles was 2.63 mm in the control group while it was significantly elevating along with the ratio of earthworm casting mixture. The more numbers of tubercles, the more incomes for farm-houses; as results, higher mixture ration of earthworm casting resulted more numbers of tubercles compared to the control group (2.7 vs. 3.2-8.3 ea). In particular, in the earthworm casting groups with 80% and 100% ratios, the numbers of tubercles were 6.2 and 8.3 ea, respectively, which is 2.5 times more than those of the control group. These results indicate that earthworm casting treatment may be utilized in G. mihanovichii farming houses for short term production of tubercles. In the group with 40% and 60% of earthworm casting mixture, the numbers of tubercles were found to be 4.5 and 4.8 ea, respectively which is higher than the control group as well; in these groups, there were no issues with soil drainage as well as moss formation. Given the analysis results of growth characteristics of G. mihanovichii, it was concluded that 40% and 60% of earthworm casting mixture might be the optimal ratios.