• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.235-242
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• 2018

BACKGROUND: About 81% of nitrous oxide ($N_2O$) emissions from agricultural land to the atmosphere is due to nitrogen (N) fertilizer application. Mitigation of $N_2O$ emissions can be more effective in controlling biochemical processes such as nitrification and denitrification in the soil rather than decreasing fertilizer application. The use of urease inhibitors is an effective way to improve N fertilizer efficiency and reduce $N_2O$ emissions. Several compounds act as urease inhibitors, but N-(n-butyl) thiophosphoric triamide (NBPT) has been used worldwide. METHODS AND RESULTS: Hot pepper and chinese cabbage were cultivated in five treatments: standard fertilizer of nitrogen-phosphorus-potassium(N-P-K, $N-P_2O_5-K_2O$: 22.5-11.2-14.9 kg/ha for hot pepper and $N-P_2O_5-K_2O$: 32.0-7.8-19.8 kg/ha for chinese cabbage), no fertilizer, and NBPT-treated fertilizer of 0.5, 1.0, and 2.0 times of nitrogen basal application rate of the standard fertilizer, respectively in Gyeonggi-do Hwaseong-si for 2 years(2015-2016). According to application of NBPT-treated fertilizer in hot pepper and chinese cabbage, $N_2O$ emission decreased by 19-20% compared to that of the standard fertilizer plot. CONCLUSION: NBPT-treated fertilizer proved that $N_2O$ emissions decreased statistically significant in the same growth conditions as the standard fertilization in the hot pepper and chinese cabbage cultivated fields. It means that NBPT-treated fertilizer can be applied for N fertilizer efficiency and $N_2O$ emissions reduction.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.4
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• pp.225-231
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• 2023

This study was carried out to investigate the growth characteristics, yield and chemical compositions of whole crop barley (Hordeum vulgare L.) according to mixing ratio of chemical fertilizer (CF) and liquid swine manure (LSM) in the paddy field cultivation. The experimental design was arranged in a randomized block design with five treatments and three replications. The manure fertilizer ratio of five treatments were CF 100% (T1), CF 70% + LSM 30% (T2), CF 50% + LSM 50% (T3), CF 30% + LSM 70% (T4), and LSM 100% (T5) of whole crop barley. At this time, the application of liquid swine manure was based solely on the nitrogen. Plant length was higher at T1 as compared to other treatments (T2, T3, T4 and T5). Fresh yield, dry matter yield and total digestive nutrients (TDN) yield were the highest in T1, whereas the lowest in T5 treatment (p<0.05). Chemical compositions (crude protein, crude fat, neutral detergent fiber, acid detergent fiber and TDN) did not show significant difference among treatments. Ca and Na contents were significantly lower at T1 as compared to other treatments (T2, T3, T4 and T5). However, Mg and P contents were significantly higher at T1 as compared to other treatments(p<0.05). There was no significant difference in total free sugar content among T2, T3, T4 and T5 treatments, but the chemical fertilizer (T1) was significantly lower than the other treatments (p<0.01). Considering the above results, liquid swine manure application showed lower dry matter yield and TDN yield than chemical fertilizer, but higher free sugar content. Therefore, in order to increase the productivity of whole crop barley, it is considered desirable to mix liquid fertilizer with chemical fertilizer, taking into account the decomposition rate and insufficient components (P, K) of the liquid swine manure.

• Journal of Venture Innovation
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• v.7 no.1
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• pp.151-166
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• 2024

The global economic growth rate has been slowed due to changes in the economic and social environment related to the recent trends in the construction market and construction industry, prolonged inflation, intense tensions among countries, and increased interest rates. Since the workers in the construction industry, due to the nature of the industry, move to another site after the completion of an awarded project rather than staying for a long time while performing work at one workplace, various issues are brought out such as poor working environment resulting from unfairness in construction contracts, aging of workers, their anxiety, and job instability. The previous studies on the turnover intention of construction industry workers mainly dealt with external aspects such as leadership, job embeddedness, and organizational citizenship behavior, while the psychological impact was overlooked. The purpose of this study was to develop a measure to reduce or alleviate turnover intention of construction industry workers by verifying empirically the relationship among psychological capital, organizational commitment, and turnover intention among them. For the purpose, whether psychological capital influences organizational commitment and turnover intention, the impact of organizational commitment on turnover intention, and whether organizational commitment has a mediating effect in the relationship between psychological capital and turnover intention, among 310 construction industry workers in the metropolitan area. The results are as follows: First, hope and self-efficacy were found to have a negative (-) effect on turnover intention, while resilience and optimism from psychological capital did not have a significant effect. Second, hope, resilience, and optimism from psychological capital were found to have a positive (+) effect on organizational commitment, while self-efficacy from psychological capital had no significant effect. Third, organizational commitment was found to have a significant mediating effect on the relationship between hope from psychological capital and turnover intention. The results of this study showed that, in construction industry workers, psychological capital affects turnover intention through the mediating effect of organizational commitment. While previous studies mainly considered external influences on the turnover intention of construction industry workers, this study has academic implications in that it sought to strengthen organizational commitment and alleviate turnover intention by approaching psychological aspects. As a practical implication, it was found that higher self-efficacy and hope for work in the organization, from psychological capital, in the construction industry workers were found to lower turnover intention through job performance in a psychologically stable state. It is considered, therefore, that various systems, including job autonomy and flexible work, should be established to improve self-efficacy and hope.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.11a
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• pp.80-90
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• 2004

Three experiments were performed to test the assumption that imbalanced dietary amino acid mixtures must lead to increased heat production (HP). The first experiment was based on diets formulated to have a wide range of crude protein (CP) concentrations but a fixed concentration of lysine, formulated to be the first-limiting amino acid. In the second (converse) experiment, lysine concentration was varied over a wide range while CP content was kept constant. To prevent the masking of dietary effects by thermoregulatory demands, the third experiment was performed at 30 $^{\circ}C$ with the diets similar to the diets used in the second experiment. The detailed relationships among amino acid balance, nitrogen (N) metabolism and energy (E) metabolism were investigated in a computer-controlled chamber calorimetry system. The results of experiments were compared with the predictions of a computerised simulation model of E metabolism. In experiment 1. with constant lysine and varying CP, there was a 75 % increase in N intake as CP concentration increased. This led to a 150 % increase in N excretion. with no significant change in HP. Simulated HP agreed with the empirically determined results in not showing a trend with dietary CP. In experiment 2, with varying lysine but constant CP, there was a 3-fold difference in daily weight gain between the lowest and highest lysine diets. HP per bird increased significantly with dietary lysine concentration. There was still an effect when HP was adjusted for body weight differences, but it failed to maintain statistical significance. Simulated HP results agreed in showing little effect of varying lysine concentration and growth rate on HP. Based on the results of these two experiments, the third experiment was designed to test the response of birds to dietary lysine in high ambient temperature. In experiment 3 which performed at high ambient temperature (30 $^{\circ}C$), HP per bird increased significantly with dietary lysine content, whether or not adjusted for body-weight. The trend was greater than in the previous experiment (20 $^{\circ}C$).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.257-263
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• 1992

Immature embryos were tested for investigating the effect of cold treatment duration and GA$_3$ concentration on the vernalization response in barley. Immature embryos were cultured on B$_{5}$ medium with GA$_3$ for 5 days, and were transplanted under 20/15$^{\circ}C$ temperature after cold treatment. Germination rate and shoot length were increased more in 20-day-old embryos than those in 13-day-old ones but germination day was decreased. Addition of 1 or 10 ppm of GA$_3$ to B5 medium was effective on the growth of immature embryos. The higher GA$_3$ concentration was, the shorter time from embryo culture to flag leaf emergence and heading was. The earlist flag leaf emergence and heading were showed on treatment of 1 or 10 ppm of GA$_3$, but GA$_3$ did not completely replace vernalization. The days to flag leaf emergence of immature embryo-cultured barley with cold treatment for two and three weeks was shortened by 3 and 18 days at 1 ppm GA$_3$, and 16 and 20 days at 10 ppm GA$_3$, respectively, when compared to 0 ppm GA$_3$ culture with cold treatment for three weeks. It was at 10 ppm GA$_3$ with 3 weeks cold treatment that showed the lowest culm length, spike length and number of grain per spike. GA$_3$ concentration was not correlated significantly with each character in 1 week cold treatment, but was significant with each character in 2 weeks. In 3 weeks cold treatment, it was except for days to heading. Correlation between cold treatment duration and culm length was negative in 0 ppm GA$_3$. In 1 or 10 ppm of GA$_3$, all characters had highly negative correlation with cold treatment duration.n.

• Clinical and Experimental Pediatrics
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• v.48 no.8
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• pp.846-856
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• 2005

Purpose : To measure the peak myocardial tissue velocities and patterns of longitudinal motion of atrioventricular(AV) annuli and assess body weight and heart rates-related changes in normal children. Methods : Using pulsed wave Tissue Doppler Imaging(TDI), we measured peak systolic, early and late diastolic myocardial velocities in 72 normal children at six different sites in apical-4 chamber (A4C) view and at four different sites in apical-2 chamber(A2C) view and compared those values with each other, also observing effects with body weights and heart rates. Longitudinal motions of the AV annuli were measured at three different sites in A4C. Results : There were no significant differences of the TDI parameters between gender, ECHO-machines and among the three Doctors performing TDI. Peak myocardial velocities were significantly higher at the base of the heart than in the mid-ventricular region and in the right lateral ventricular wall than in the left lateral ventricular wall or IVS. The TDI parameters showed no significant correlation with fractional shortening(%). Peak systolic and early diastolic myocardial velocities had no correlation with heart rates, but peak late diastolic velocities and A/E ratio correlated positively with heart rates. Correlations between the TDI parameters and body weight were inconsistent. Absolute longitudinal displacement and % displacement were not differ between gender and not correlated with the TDI parameters. Conclusion : We measured the peak myocardial velocities with TDI and the longitudinal motion of the AV annuli using M-mode echocardiography in normal children. With more large scale evaluation, we may establish reference values in normal children and broaden clinical applicabilities in congenital and acquired heart diseases.

• The Korean Journal of Malacology
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• v.15 no.1
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• pp.31-39
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• 1999

This study was aimed to describe the population dynamics and secondary production of Tapes philppinarum on Chohwa and Toksan tidal flats in Kwangyang Bay, from June 1994 to July 1995. The size distributions in shell length showed bimodal patterns from June 1994 to April 1995. Thereafter the distribution changed to the passage of time, indicating an increase in shell length. The mean densities decreased gradually with month. Chohwa A sustained highestdensity, followed by Chohwa B, Toksan C, and Toksan D. The recruitment of new year class occurred first on the upper tidal flat, and then moved to the lower tidal flat. The mean biomass in flesh dry weight of each year class increased in spring just before the spawning period, and thereafter decreased progressively. Annual mean biomass wasrecorded as 170.7 g m$\^$-2/ at Chohwa A, 220.7 g m$\^$-2/ at Chohwa B, 21.8 g m$\^$-2/ at Toksan C, and 45.2 g m$\^$-2/ at toksan D. Annual productions of Ruditapes philippinarum were estimated as 259.72 g m$\^$-2/ yr$\_$-1/ at Chohwa A, 359.79 g m$\^$-2/ yr$\_$-1/ at Chohwa B, 45.02 g m$\^$-2/ yr$\_$-1/ at Toksan c, 68.88 g m$\^$-2/ yr$\_$-1/ at Toksan D. Annual productions were much higher on Chohwa tidal flat than those on Toksan tidal flat. While P:B ratio were higher on Toksan tidal flat as 1.70 than those on Chohwa tidal flat as 1.58. In conclusion, the Chohwa tidal flat showed higher biomass and producion of Ruditapes philippinarum, whereas the Toksan tidal flat showed higher P:B ratio. The total amount of potential food might influence on the density, biomass nad produciton, whereas the amount of food and space per individual might influence on the growth rate and P:B ratio.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.747-756
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• 1995

To find out the optimum application method of slow-releasing fertilizer(SRF) and conventional fertilizer(CF) with different fertilization rate under two culture methods[l0-day old seedling machine transplanting(MT) and direct-sowing on dry paddy(DS)] in the south-western region(clay loam soil) of Korea, used were Chosun slow-releasing fertilizer(silicate latex coated fertilizer: N-P$_2$O$_{5}$-K$_2$O =18-12-13) and conventional fertilizer. Plant height and number of tillers with different two culture methods were higher at MT than DS in early growth. The ratio of dry weight in heading stage was higher at CF than SRF in MT than DS and especially, SRF 80% + CF 20% than SRF 100% or CF 100%. Leaf area index (LAI) in heading stage was higher at CF in MT but higher at SRF in DS than their counterparts. Chlorophyll content was higher at SRF than in CF expect for heading stage(HS), especially in DS. It was highest at HS in CF without its difference during maximum tillering stage(MTS) and panicle formation stage(PFS), while highest at PFS in SRF with tendency of gradual increase and decrease before and after PFS, respectively. Heading was delayed 2~3 days at SRF in two cultrue methods and 4~5 days at SRF in DS in comparison with CF in MT with delay of 2 days at DS compared with MT. Culm length was longer at CF in MT and at SRF in DS than their counterparts. Panicle number per m was more at SRF and in DS. Filled grain ratio was higher at CF and in MT. Yield was obtained 101 and 100% at 100% and 80% level of SRF in DS respectively, and 96% at 80% level of CF in MT, compared with conventional application method (516kg /l0a), and increased 2~4% at DS and 0~3% at MT in SRF. Yield was high in order of 100%(SRF) =80%(SRF) + 20%(CF) > 100%(SRF) + 20%(CF) > 80%(SRF) at MT and 80%(SRF) + 20%(CF) =100%(SRF) > 80%(SRF) =100%(SRF) + 20%(CF) at DS.

• Journal of the Korean Society of Food Science and Nutrition
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• v.6 no.1
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• pp.41-47
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• 1977

This study was designed to evaluate the nutritive value of pearl barley. Forty males and the same number of females of albino rats, the Leuise strain, weighing from 52.1g to 59.1g were divided into eight experimental groups, five males and females were composed of one group. A group: casein 15%+starch 75%+oil 8%+vitamin mixture 1%+salt mixture 1% B group: pearl barley 98%+vitamin mixture 1%+salt mixture 1% C group: rice 98%+vitamin mixture 1%+salt mixture 1% D group: barley 98%+vitamin mixture 1%+salt mixture 1% E group: rice 49%+pearl barley 49%+vitamin mixture 1%+salt mixture 1% F group: rice 73.5%+pearl barley 24.5%+vitamin mixture 1% +salt mixture 1% G group: barley 49%+pearl barley 49%+vitamin mixture 1% +salt mixture 1% H group: barley 73.5%+Pearl barley 24.5%+vitamin mixture 1%+salt mixture 1% The rats were kept in an individual cage and were fed 8 different diets for 7 weeks and fed by ad-libitum feeding method. The results of this study were eluciated as followings. 1. B group was significantly lower in weight gain than the other groups. 2. Polished pearl barley showed higher digestion rate in protein and carbohydrate than brown pearl barley but lower in fat. 3. Liver weight was obserbed significant differences between B group and C group. but no significant differences between the others. 4. B group was significantly lower in the total protein content of liver and A/G ratio in plasma than other groups. 5. B group was also the lowest in the hematocrit and hemoglobin contents among the experimental groups. 6. Free amino acid composition in plasma was similar to those in diet.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.8
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• pp.960-964
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• 2007

This study was performed to examine the toxicity of Psoralea corylifolia L. by the single-dose oral toxicity tests in rat and bacterial reverse mutation assay. In single-dose oral toxicity tests, 5 mL ethanol extract of P. corylifolia L. were directly injected into 10 rats (5 males and 5 females) at a dosage of 2 g/kg. Death practice was not detected during breeding periods (14 days), and $LD_{50}$ was calculated over 2 g/kg. No difference were observed with control group in the growth rate and histological observations. In bacterial reverse mutation assay, his(-) Salmonella Typhimurium TA98, TA100, TA1535, TA1537 and trp(-) Escherichia coli WP2uvrA (pKM101) were used for assessing the toxicity of ethanol extracts of P. corylifolia L.. No significant difference in formation of the colonies and no dose-dependent increase was observed regardless of the addition of S9 mix. The results showed that ethanol extracts of P. corylifolia L. did not have single-dose oral toxicity and mutagenic toxicity.