• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.259-266
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• 1998

A study on the biological and chemical characteristics in the middle last Sea of Korea was carried out at 31 stations in October $11\~18$, 1995 on board the R/V Tam-Yang. The chlorophyll a concentration, new and regenerated production, and the vertical diffusion of nitrate from the thermocline structure were investigated. From the vertical distribution of chlorophyll a, subsurface maxima were observed near the thermorline at most stations including the frontal zone, except at the southern stations where the maximum chloropyll a concentration occurred at the surface, The nanophytoplankton was the most dominant fraction comprising $83.5\%$ of total phytoplankton cell numbers, but netphytoplankton were common at the southern stations where the dominant species were Rhizosolenia sp. Nitrogenous new production and regenerated productions were measured using the stable isotope $^{15}N$ nitrate and ammonia uptake method. The vertically integrated nitrogen production varied between 8.470 and $72.945\;mg\;N\;m^{-2}\;d^{-1}$. The f-ratio, which is the traction of new production from primary production, waried between 0.03 and 0.72, indicating that $3\%$ to $72\%$ of primary production was supported by the input of nutrients from below the euphotic zone and the rest are supported by ammonia recycled within the euphotic layer. This range of f-ratio encompasses from extremely oligotrophic to eutrophic area characteristics. The differences in productivity and f-ratio among stations were related to frontal structure and the bottom topography. The values were high near the frontal zone and low outside of it, and the station near Ulleng Island showed the highest f-ratio. Vertical diffusion coefficients were calculated from both the water column stability (Kz-1) of King and Devol's equation (1979) and new nitrogen requirement (Kz-2). The values of Kz-2 ($0.11\~0.55\;cm^2/s$) were relatively low compared to the values reported previously.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.768-774
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• 2009

To improve the productivity of 1,3-propanediol(1,3-PD) with K. pneumoniae DSM4799 using pure glycerol and crude glycerol derived from the biodiesel process, optimizing fermentation conditions was performed by changing environmental factors such as anaerobic/aerobic condition, temperature, glycerol concentration, and pH. When anaerobic conditions were maintained, there was an improved 1,3-PD production compared with that from aerobic/anaerobic 2-stage fermentation. From the results with temperature $26{\sim}37^{\circ}C$, the higher 1,3-PD production yield was observed at $30{\sim}33^{\circ}C$. For an initial glycerol concentration higher than 60 g/L, cell growth and 1,3-PD production were inhibited. When crude glycerol was used, the initial 1,3-PD production appeared to be inhibited. After 48 hr of incubation, however, 1,3-PD production with crude glycerol was even higher than that with pure glycerol, demonstrating the feasibility of 1,3-PD production using crude glycerol as a substrate. Fed-batch fermentation was applied for the high concentration of 1,3-PD without substrate inhibition. By regulating pH at 7 during the fed-batch with glycerol lower than 40 g/L, the yield of 1,3-PD was 25% higher than that without pH regulation(0.56 g/g vs. 0.45 g/g). In conclusion, based on our results, anaerobic conditions, temperature at $30^{\circ}C$, pure or crude glycerol lower than 40 g/L, and pH regulation at 7 were the optimized conditions for 1,3-PD production using K. pneumoniae DSM4799, making it more feasible to produce 1,3-PD at higher concentration and a lower price.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.407-414
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• 2016

This study was conducted to investigate the effects of supplementation of dietary betaine on nutrient digestibility and physiological responses in finishing pigs. A total of twelve pigs with a body weight of $80.1{\pm}3.7kg$ were individually caged, and randomly assigned to one of the two experimental diets containing 0 (control) or 5 g/kg (treatment) of the betaine in a $2{\times}2$ Latin square design. The experimental period was 14 days-7 days adaptation and 7 days trial period-per phase. All data for the difference between control and treatment groups were statistically analyzed by student's t-test. Dry matter and crude protein digestibility in the treatment group were significantly improved by 1% and 1.3%, respectively, as compared with those in the control (p<0.05). The apparent absorption of dietary energy was increased from 82.3% to 83.7% by dietary betaine supplementation. Thus, the retention of energy was also significantly increased to above 6% in the treatment group compared with the control group (control 4,057 vs treatment 4,314 kcal; p<0.01). The physiological parameters indicating serum biochemical contents and stress-, immune-, and inflammatory- responses were not changed by the supplementation of dietary betaine. In conclusion, dietary betaine improves the nutrient digestibility without any negative effects in terms of physiology in finishing pigs. It suggests that the supplementation of dietary betaine may increase the productivity through the improvement of weight gain and feeding efficiency.

• Korean Journal of Weed Science
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• v.12 no.1
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• pp.61-69
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• 1992

Weed control in mid season of rice fields was systemized earlier in Korea than in Western Europe or China. The most representative method was pull out the weeds by hand followed by 'Seojibeob'(鋤地法 : method of hoeing) after draining. It was practiced 3 to 4 times to do extensively. Also, the purposes of transplanting arid direct seeding in rows were to manage weed problems effectively, which means that the development of cultural techniques is closely related to 'Seojibeob'(鋤地法). From the 17th century, techniques of deep plowing(because of principal : 'Simkyonginu'(深耨易耕 : Deep plowing make easy to hoe) and 'Hwanubeob'(火耨法 : derived from 'Hwakyong soonubeob) for effective weed management of waste lands were newly adopted and spreaded due to the situations ant that time. Thus, the practice of large-scale farming resulted from the adaptation of the techniques and methods described above. In the 18th to 19th century, the cultural methods, not much different from 'Seojibeob', were changed and the number of weeding was decreased. Especially, the techniques of dry seeding of rice were practiced by originating the ideal 'Seojibeob', in which water availability was improved in northern drought areas and also weed problems were easily managed. In addition, intensively large-scale farming showed weed management problems, so that 'Cheonilrok'(千一錄) by Woo Ha-young described the techniques of 'Banjongbeob'(反種法) or 'Hwanubeob' and in the end of the Chosun dynasty extensively large-scale farming was practiced by putting intensive and extensive techniques together. As the results, agricuitural productivity of Korea was increased 5 times by that time.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.772-778
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• 2012

In order to develop the application method of compost manure (CM) and liquid manure (LM) for rice cultivation, experiments were conducted at silty loam paddy field in Gochang, Jeonbuk, a LM applied rate as N%; non-application, chemical fertilizer (CF) 100%, CM 50%+LM 50%, CM 30%+CF 70% and CM 30%+LM 70% as basal and additional fertilizer. $NH_4^+$-N content in paddy soil was higher with CF 100% application than the split application of compost and liquid pig manure fertilizer during the early stage of rice growth. However, there was no significant difference in the later part of rice growth. Amount of $NO_3^-$-N in leachate was decreased in CM 30%+LM 70% and CM 30%+CF 70% split applications compared to CF 100%. Amounts of OM and Avail $P_2O_5$, Exch. cations in soil of experiment after were highest with the split application of CM 50%+LM 50% and CM 30%+LM 70%. Amount of nutrient uptake of plants were no significant difference between the split application plots of CM and LM, but nitrogen utilization rate was 66% in average CM 50%+LM 50% and CM 30%+LM 70% to compared CF 100%. The rice yield of CM 50%+LM 50% was lower (90%) comparing that of CF 100% ($557kg\;10a^{-1}$). But the yield in CM 30%+CF 70% and CM 30%+LM 70% reached 96% in average, which did not show significant difference with that of CF 100%. Accordingly, LM 70% or CF 70% split application after CM 30% application was helpful in enhancing the physicochemical property of soil as well as reducing CF. It could be evaluated that this application in segmentation was better in productivity improvement and soil pollution reduction than the esinultaneous application of LM 100% in terms of split application in times of requirement for plants.

• KSBB Journal
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• v.24 no.1
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• pp.30-40
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• 2009

Statistical optimization of the production medium was carried out in order to find an optimal medium composition in itaconic acid fermentation process. Itaconic acid utilized in the manufacture of various synthetic resins is a dicarboxylic acid biosynthesized by fungal cells of Aspergillus terreus in a branch of the TCA cycle via decarboxylation of cis-aconitate. Through OFAT (one factor at a time) experiments, six components (glucose, fructose, sucrose, soluble starch, soybean meal and cottonseed flour) were found to have significant effects on itaconic production among various carbon- and nitrogen-sources. Hence, using these six factors, interactive effects were investigated via fractional factorial design, showing that the initial concentrations of sucrose and cottonseed flour should be high for enhanced production of itaconic acid. Furthermore, through full factorial design (FFD) experiments, negative effects of $KH_2PO_4$ and $MgSO_4$ on itaconic acid biosynthesis were demonstrated, when excess amounts of the each component were initially added. Based on the FFD analysis, further statistical experiments were conducted along the steepest ascent path, followed by response surface method (RSM) in order to obtain optimal concentrations of the constituent nutrients. As a result, optimized concentrations of sucrose and cottonseed flour were found to be 90.4g/L and 53.8g/L respectively, with the corresponding production level of itaconic acid to be 4.36 g/L (about 7 fold higher productivity as compared to the previous production medium). From these experimental results, it was assumed that optimum ratio of the constituent carbon (sucrose) and nitrogen (cottonseed flour) sources was one of the most important factors for the enhanced production of itaconic acid.

• KDI Journal of Economic Policy
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• v.13 no.2
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• pp.69-96
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• 1991

Economic circumstances of enterprise began to change after a series of democratization measures in 1987. Accompanied with it, competitive advantage of enterprise began to change as well. By that time Korean enterprises had a competitive advantage based on low wages of labor. Abrupt and steady upsurge in wage, however, weakened competitive advantage based on low wages, upward revaluation of won currency caused by surplus in BOP strengthened upward trend in price increase of export products. An urgent problem in Korea economy is, therefore, to find 'new' competitive advantage. For the time being preserving competitiveness based on cost advantage must inevitably remain our basic strategy in industrial policy. While cost advantage in the past referred to low wage level, this cost advantage must have foundation on the improvment in producing technology, which will increase labor productivity and decrease unit cost of products. Besides, other measure to improve competitiveness can be considered such as increasing the extent of production automation, self-development of new products, and spread and strengthening subcontracting system among various enterprises. In this paper we tried to perceive how subcontracting system as a form of intercompany division of labor operates and to which direction this system proceeds responding to the recent changes in economic circumstances. Speaking more concretly, we tried to perceive how large the gap of bargaining power between mother-company and subcontracting company is and how effectively subcontracting company's technical power contributes to mother-company. Facing up to weakeening of competitiveness, how stably is the partnership between mother-company and subcontracting company established and what measures are being prepared to retore the weakened competitiveness. In conclusion the result of investigation through the questionaire on subcontracting system is positive, from which we can infer the optimistic view of restoring Korean economy's competitiveness.

• Sleep Medicine and Psychophysiology
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• v.10 no.2
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• pp.93-99
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• 2003

Objectives：Sleep loss and excessive daytime sleepiness may have serious consequences, including traffic and industrial accidents, decreased productivity, learning disabilities and interpersonal problems. Yet despite these adverse effects, there are few epidemiological studies on sleep loss and daytime sleepiness in the general population of Korea. This study investigates the number of people who suffer from sleep insufficiency, how much recovery sleep occurs on weekends, and the relationship between the amount of recovery sleep and daytime sleepiness. Methods：A total 164 volunteers, aged 20 and over, were recruited by advertisement. The subjects were workers and college students living in Seoul, Korea. Subjects were excluded if they were aged over 60；if they had medical, neurological, psychiatric or sleep disorders that could cause insomnia or daytime sleepiness；if they were not following a regular sleep schedule；if they traveled abroad during the study；or if they did not leave home to work or were shift workers. They were interviewed and given a sleep log to complete on each of 14 consecutive mornings. They also completed the Epworth Sleepiness Scale (ESS) at noontime on the last day of the second week. All statistical data were analyzed by t-test, $X^2$-test or ANOVA, using SPSS/PC+. Results：The results showed that the subjects woke up at 6：50 (${\pm}1$：16) on weekdays, 7：09 (${\pm}1$：29) on Saturdays, and 8：12 (${\pm}1$：39) on Sundays and holidays. They took more frequent and longer naps on Sundays than on weekdays and Saturdays. The mean sleep duration was 6h 35 min. on week nights, with a mean increase of about 1h on weekends. Only 9.1% of the subjects spent more than 8h in bed on week nights, with 67% spending less than 7h, and 49.4% reported recovery sleep of more than 1h on Sundays. The subjects who reported recovery sleep of more than 2h on Sundays, showed significantly more excessive daytime sleepiness than those who reported less than 30 min (F=2.62, p<.05). Conclusions：These findings suggest that sleep insufficiency and excessive daytime sleepiness are relatively common in Korea, and that the people who get insufficient sleep on weekdays try to compensate for sleep loss with oversleeping and daytime napping on Sundays and holidays. It appeared that daily sleep insufficiency had a cumulative effect and increased daytime sleepiness.

• Journal of Plant Biotechnology
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• v.42 no.3
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• pp.161-167
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• 2015

Sweetpotato [Ipomoea batatas (L.) Lam] grows well in harsh environmental conditions, and is cultivated as one of the top seven food crops in the world. Recently, sweetpotato is drawing interest from people as a healthy food because it is high in dietary fiber, vitamins, carotenoids and overall nutrition value. However, few studies have been conducted on sweetpotato genome sequencing in spite of its importance. This review is aimed at increasing the efficiency of sweetpotato genome sequencing research as well as establishing a base for gene utilization in order to control useful traits. Recently, animal and plant genome sequencing projects increased significantly. However, sweetpotato genome sequencing has not been performed due to polyploidy and heterogeneity problems in its genome. Meanwhile research on its transcriptome has been conducted actively. Recently, a draft of the diploid sweetpotato genome was reported in 2015 by Japanese researchers. In addition, the Korea-China-Japan Trilateral Research Association of Sweetpotato (TRAS) has conducted research on gene map construction and genome sequencing of the hexaploid sweetpotato Xushu 18 since 2014. The Bill & Melinda Gates Foundation launched the 'sweetpotato genomic sequencing to develop genomic tools for Sub-Sahara Africa breeding program'. The chloroplast genome sequence acquired during sweetpotato genome sequencing is used in evolutionary analyses. In this review, the trend of research in the sweetpotato genome sequencing was analyzed. Research trend analysis like this will provide researchers working toward sweetpotato productivity and nutrient improvement with information on the status of sweetpotato genome research. This will contribute to solving world food, energy and environmental problems.

• Journal of Preventive Medicine and Public Health
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• v.7 no.2
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• pp.383-393
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• 1974

The importance of the health care for the miners not only concerns the productivity of the enterprises but also as a fundamental human right, it has to be secured and protected by the society and the government. The Korean coal miners began to find their works at overseas since 1963 when the Korean government selected and dispatched its miners to West Germany. As years go by, the demand and the supply of the coal miners, the program of the coal miners health care became the important tasks to be solved and the further studies and research were necessary to support these tasks achievement. The writers made a statistical analysis on health status of the 1,559 Korean applicants applying for the coal miners in West Germany during the year of 1972 and 1973 by the using of the data of physical examination which were directed by the Korea Overseas Development Cooperation. The standard of physical examination which was applied for coal miners applying the jobs in West Germany was authorized by the Government Office of Labor in 1967. The results are as following; 1. The applicants were from the various provinces throughout Korea; Gang Weon 50.2%, Jeon-Nam 16.8%, Chung-Nam 13.7%, Gyeong-Nam 10.5%, City of Seoul 5.4%, and others 3.7%. 2. The ages of the applicants were from 20 to 44. The age group of 25-29(36.3%) and of 30-34(55.2%) together occupied the 91.5 per cent of the total applicants. 3. Among the 1,559 applicants 52.1 per cent passed the physical examinations. The tendency were shown that as the age increased, the passing rate decreased, and the married applicnts had lower passing rates compared to the unmarried applicants. 4. The height of the applicants averaged $168.4{\pm}4.74(cm)$ and the weight averaged $61.3{\pm}5.65(kg)$. 5. The average vision of the left eye of the applicants was $0.92{\pm}0.23$ and the right eye was $0.91{\pm}0.30$. 6. The mean value of the systolic blood pressure of the applicants was $145{\pm}13(mmHg)$ and the diastolic blood pressure was $85{\pm}8(mmHg)$. 7. Fifteen hundred and fifty-nine applicants were taken chest X-ray and 17.2 per cent were found abonrmal. For each 1,000 applicants, 46 Pulmonary calcification and fibrosis, 45 chronic bronchitis, 27 pleural thickening and adhesion, 20 pulmonary tuburculosis, 11 anomalies of the rib, 10 pulmonary infiltration and 21 others diseases were found. 8. Lumber X-ray examination showed that 23.9 per cent (372 applicants) were found abnormal. For each 1,000 applicants, 77 osteoarthritis, 56 lumbarization, 15 fracture of vertebrae, 15 spondyloarthritis, 14 deformity of vertebrae, 13 spina bifida, 12 sacralization, 12 spondylolysis, and 5 others diseases were found. 9. In total, 47.9 per cent of 1,559 applicants failed the physical examinations, and the main causes for the failure were shown to be 7.1% of anomalies of spine, 6.3% of osteoarthritis, 4.7% of pulmonary calcification and fibrosis, 4.6% of chronic brochitis, 3.6% of hypertension (only), 3.4% of fracture of vertebrae. 3.1% of underweight(under 57.0kg), 2.0% of spondyloarthritis, 2.0% oe pulmonary tuberculosis, 1.7% of pleurisy, 1.0% of spina bifida, 1.5% of syphilis, 1.5% of color blindess, and 1.0% of underheight(under 160.0cm).