• Asia pacific journal of information systems
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• v.23 no.4
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• pp.1-28
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• 2013

Given that smartphone-based social network services (SNS), such as KakaoStory is now being widely used as a way for people to connect and communicate with each other, this study examines key factors leading to the continued use of SNS. People have been using PC-based SNS, such as Cyworld, for years are now using smartphone-based SNS, such as KakaoStory. KakaoStory developed by KakaoTalk has rapidly grown up as the largest smartphone-based SNS in Korea as smartphone penetration increases. It is more difficult for firms to maintain their current users over time in that alternative SNSs satisfying people's new needs are constantly emerging and evolving. In this sense, one of the most challenging issues for SNS firms is how to retain their current users in the long run. However, there are few empirical studies on this issue. Applying the IS continuance model proposed by Bhattacherjee [2001], this study explores key determinants of users' smartphone-based SNS continuance intention. The model suggests that perceived usefulness and user satisfaction are the key determinants of IS continuance intention. However, the model includes only the utilitarian value that users can obtain through the use of smartphone-based SNS, by considering perceived usefulness. Therefore, the study attempts to extend the IS continuance model by considering hedonic and social values simultaneously. More specifically, we consider subjective norms as social value that are proposed by the theory of reasoned action and the theory of planned behavior. We also consider perceived enjoyment as hedonic value that is emphasized as a key factor influencing users' behavior intention and actual behavior, particularly in the context of hedonic IS use. By considering the three values in our model simultaneously, we could offer a deeper understanding of smartphone-based SNS continuance. That is, this study could offer an explanation of how each value is associated with user satisfaction and SNS continuance intention. The customer value-satisfaction-loyalty model can strengthen the assertion that smartphone-based SNS continuance intention is determined by various different types of customer values, such as utilitarian, hedonic, and social ones. Moreover, the model provides a theoretical basis for the assertion that customer values lead to increased loyalty via customer satisfaction. In this regard, we theorize that SNS continuance intention is influenced by users' various values, namely perceived usefulness, perceived enjoyment, and subjective norms, via user satisfaction. To test the proposed research model and hypotheses, we conducted a partial least squares analysis using a total of 253 data collected on the users of smartphone-based SNS (i.e., KakaoStory). The key findings are as follows: First, it has been found that SNS continuance intention considerably depends on user satisfaction. Second, user satisfaction is determined by confirmation, perceived usefulness, and perceived enjoyment. Third, concerning the effects of the three values on SNS continuance intention, only perceived enjoyment regarded as hedonic value was statistically significant. That is, perceived usefulness considered as utilitarian value and subjective norms considered as social value had no effect on SNS continuance intention. Finally, our results indicate that confirmation increases perceived usefulness, perceived enjoyment, and user satisfaction. The results reconfirm the effectiveness of IS continuance model in predicting smartphone-based SNS continuance intention. Moreover, the results demonstrate that perceived enjoyment reflecting hedonic value is the most important predictor of SNS continuance intention. Therefore, it is imperative for firms to meet SNS users' hedonic value to retain them in the long run. Meanwhile, we could not find any empirical evidence to support the assertion that subjective norms are associated with user satisfaction and SNS continuance intention. The results lead us to conclude that when users have enough direct experience in SNS use, subjective norms have no effect on SNS continuance intention. Discussions and implications of the results are provided.

• Horticultural Science & Technology
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• v.31 no.5
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• pp.552-557
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• 2013

This study was carried out to investigate the different DIF (day/night temperature differential) treatments on early growth of sweet pepper plants (Capsicum annuum L.) after planting. The DIF treatments were thus as follows. DIF levels are DIF-6 ($20-26^{\circ}C$) and DIF 0 ($23^{\circ}C$), DIF 3 ($24.5-21.5^{\circ}C$) and DIF 6 ($26-20^{\circ}C$). The DIF 3 and DIF 6 treatments significantly increased plant height of the sweet pepper plants during ten weeks after planting compared to DIF-6 and DIF 0. Leaf area per plant of DIF 3 treatment constantly increased and the level was greatest leaf area at ten weeks after planting. Fresh weight per plant treated with DIF-6 was lower and was reduced 74-77% range compared to other treatments. DIF 0 and DIF 3 treatments significantly affected dry weight and percentage of dry matter compared to DIF-6 and DIF 6. Especially DIF 6 treatment significantly decreased from eight weeks after planting. Percentage of dry matter of the leaf treated with DIF 0 and DIF 3 consistently increased from six weeks after planting, however, DIF-6 and DIF 6 treatments dramatically decreased from eight weeks after planting. High levels of DIF management cause growth retardant on early growth of sweet pepper plants, especially when night temperature is higher than day temperature, plants are indicated to be greater growth retardant.

• Korean Journal of Ecology and Environment
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• v.35 no.3 s.99
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• pp.237-246
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• 2002

Tamjin Dam is built in the upper reaches of the Tamjin River which flows through the Janghung-gun and Gangjin-gun of the Jeollanamdo, Korea. In order to map out a preservation strategy of the fish community from dam construction, We studied the distribution of fish distribution and changes of the habitat environment. we found 49 fish species inhabiting in the downstream and upstream of the Tamjin Dam. Among them, migratory fish were two species sweet smelt, Plecoglossus altivelis and freshwater eel, Anguilla japonica. The Coreoperca kawamebari which designated as a species to be protected by The Ministry of Environment of Korea was also observed. After the dam construction, reservoir would be filled with water and running water system will change to standing water system. Then the habitat and spawning space for mountain torrent fish will be reduced and the migration of migratory fish to upstream will be blocked. Through our study, we proposed several ways to protect fish community. In order to preserve the reduced habitat and spawning area of mountain torrent fish, a fishway has been diagnosed to be built in the shallow reservoir in the entrance of the upriver. The establishment of artificial spawning ground on the riverside has been recommended. In addition, We propose a creation of a shelter for fresh water eel, Anguilla japonica in areas where the depth of the water is about l0m by laying rocks. Since it is difficult for a spawning ground to be formed naturally in the reservoir due to the year-round changes in water level, We suggested a floating spawning facility using an artificial fixture. In the downstream of the dam, a waterway-style habitat and spawning ground in the river and increasing the diversity and abundance of fish fauna in the Tamjin River. A low-cost and highly efficient operational fishway has been recommended so that migratory fish such as Plecoglossus altivelis (sweetfish) can migrate from the lower reaches to the upper reaches of the river.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.3
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• pp.295-304
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• 2011

This study was carried out to investigate the effect of harvest stage of Sorghum ${\times}$ Sorghum Hybrid (SSH) and manufacture methods of SSH silage on nutritive values and quality of SSH silage manufactured with SSH grown in paddy land of Department of Animal Resources Development, National Institute of Animal Science, RDA. SSH "SS405" was harvested at two different growth stages (heading and ripen stage) and ensiled at each harvest stages. The content of crude protein in both square baled SSH silage (SBSS) and bag silage (BS) increased with delayed harvest maturity, but the contents of ADF (acid detergent fiber), NDF (neutral detergent fiber) decreased. The contents of ADF and NDF was not influenced by the inoculation of lactic bacteria. The contents of TDN (total digestible nutrient) in both stage and in vitro dry matter digestibility (IVDMD) in heading stage was not influenced by the harvest stage of SSH. The pH in all SSH silage ranged from 3.8 to 4.4 at two different harvest stages, and pH in heading stage was higher than that of ripen stage (P<0.05). The content of lactic acid of all SSH silage increased with delayed harvest maturity (P<0.05), but the content of acetic acid decreased (P<0.05). The contents of lactic acid and acetic acid in ripen stage were not influenced by manufacture method of silage. The content of lactic acid in both SBSS was higher than that of both BS and RBSS in heading and ripen stage (P<0.05), but the content of acetic acid decreased (P<0.05). The contents of lactic acid and acetic acid in BS were similar as compared to that of RBSS. Therefore, we suggest that the quality of SSH silage in both heading and ripen stage can be improved by manufacture methods of SBSS and BS.

• The Korean Journal of Food And Nutrition
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• v.27 no.1
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• pp.22-30
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• 2014

In this study, purple sweet potato bread was prepared by the addition of 0.005%, 0.010%, 0.015% and 0.020% hemicellulase. It's effect on product quality and consumer evaluation were examined. The results showed that the dough pH and total titratable acidity were not significantly different between samples. In the fermentation power of dough expansion, a 0.015% addition sample was the highest between the samples. The bread pH decreased significantly as hemicellulase was increased, whereas. Bread total titratable acidity was significantly decreased. The addition of hemicellulase samples were significantly higher in specific volume and baking loss than the control sample. The moisture content was not significantly different between samples. In colors, the lightness of the control sample was the highest, the redness of the 0.020% addition sample was the lowest while the yellowness of the control was the lowest. The hardness and the fracturability decreased significantly as hemicellulase was increased. The resilience indicated reverse effects. In consumer evaluation, the color and softness were not significantly different between samples. And the hemicellulase addition of samples was higher in flavor than that of the control sample. The overall acceptability was the highest at 5.67 with a 0.010% addition sample. According to these results, the addition of 0.010% hemicellulase in purple sweet potato bread would be the optimum level.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.83-93
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• 2016

This study was conducted to develop a 26-week obesity management program and examine the effects of this program on obesity index (body mass index, fat mass percentage, and triglyceride) and psychological variables, self-esteem, dietary self-efficacy, physical activity self-efficacy, and body image among 46 4th-6th obese elementary school children with a BMI above $20kg/m^2$ using a nonequivalent control group quasi-experimental design (experimental group=23, control group=23). This program included a 12-week intensive course (12 times for group education on obesity, exercise, and nutrition, 36 times for practicing diet and physical exercise, and 5 times for psychological counseling) and a 14-week follow-up course (3 times for group education, 3 times for checking diet and physical exercise, and 1 time for psychological counseling. The collected data were analyzed by the Kolmogorov-Smirnov test, chi-squared test, Fisher's exact probability, t-test, and ANCOVA. There were above normal values in body mass index ($20kg/m^2$), fat mass percentage (15-20%), and triglyceride tolerance ($90mg/d{\ell}$) in experimental group and control group. The body mass index (F=94.869, p<.001), fat mass percentage (F=37.361, p<.001), and triglyceride tolerance (F=7.907, p= .007) were significantly lower, while self-esteem (F=19.661, p<.001), dietary self-efficacy (F=16.942, p<.001), physical activity self-efficacy (F=9.363, p= .004), and body image (F=9.782, p= .003) were significantly higher in the experimental group than the control group after 26 weeks. This study provides evidence that the 26-weeks obesity management program is an effective nursing intervention for managing obesity and psychological variables of obese elementary school children.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.938-946
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• 2017

This study was conducted to examine the changes in serum lipid components and blood glucose by krill (Euphausia superba) meal and sodium fluoride (NaF) in rats fed on experimental diets and administered orally to NaF 10 mg for 5 weeks. Body weight of rats decreased as the amount of krill meal diet increased, it was observed the basal diet plus NaF group (BF group) compared to the lower basal diet group (BD group). The serum concentrations of total cholesterol, LDL (low-density lipoprotein) cholesterol, free cholesterol, triglyceride (TG), phospholipid (PL) and blood glucose in serum were higher in the BF group than the 10% krill meal group plus NaF 10 mg (KF10 group) or BD group, the 20% krill meal plus NaF 10 mg group (KF20 group), the 30% krill meal plus NaF 10 mg group (KF30 group). Conversely depending on the content of krill meal for the HDL (high-density lipoprotein) cholesterol level, it showed higher results. The concentration of total protein was no significant difference among the groups (p<0.05). The results indicate that a krill meal diet effectively inhibited increases in lipid elevation and blood glucose level in the sera of rats.

• Journal of the Korean Arthroscopy Society
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• v.13 no.2
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• pp.155-160
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• 2009

Purpose: The purpose of this study was to evaluate the pain recovery pattern according to the integrity and to analyze the factors affecting the progress and level of pain postoperatively. Materials and Methods: We examined 153 patients, who were treated with arthroscopic rotator cuff repair. 101 rotator cuff tears were full-thickness tear and 52 were partial tear. The mean follow up duration was 20 months (12~30 months). We evaluated the visual analogue scale, range of motion, ASES (American Shoulder and Elbow Surgeons), and UCLA (University of California at Los Angeles) scores preoperatively and postoperatively. We analyzed the pain recovery pattern between partial and full thickness tear using Student T-test and the factors affecting the progress and level of postoperative pain using multiple regression analysis. Results: The change patterns of visual analogue scale after arthroscpoic repair were similar regardless of the tear integrity. The VAS showed a continuous decreasing pattern, but increased at first 3 weeks postoperatively and at 7 weeks postoperatively, and then, decreased thereafter. The average VAS was ${\leqq}2$ points by postoperative 3 months. The factor affecting the pain score at 3 months was related to the preoperative limitation in forward flexion ($r^2=0.377$, p=0.021). Conclusion: There was no differences of the pain recovery pattern according to the integrity, and the factor affecting the progress of postoperative pain was preoperative angle of forward elevation. So, the appropriate preoperative rehabilitation protocol that can improve motions of the shoulder joint would help to improve the level of postoperative pain and functional recovery.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1127-1132
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• 2006

In our previous study, a novel herb mixture (HIM-I) of Angelica gigas radix, Cnidium officinale rhizoma, and Paeonia japonica radix was developed to protect the intestinal and immune systems and promote its recovery against radiation damage. A new herbal composition (HemoHIM) with the high immune modulating activity was developed from HIM-I. HIM-I was fractionated into ethanol fraction (HIM-I-E) and polysaccharide fraction (HIM-I-P). And HemoHIM was prepared by adding HIM-I-P to HIM-I. HemoHIM showed more effective than HIM-I in immune modulation as well as radioprotection. The present study is designed to investigate the protective effects of HIM-I, HIM-I-P, and HemoHIM on hydrogen peroxide $(H_2O_2)$ induced apoptosis of human promyelocytic leukemia (HL-60) cells. It was shown that $H_2O_2$ treatment reduced the viability of cells, and increased appearance of DNA ladders, hypodiploid (subG1) cells, and phosphatidylserine translocation level. Pretreatment of HemoHIM significantly reduced the cytotoxic effect induced by $H_2O_2$, associated with reducing the translocation of phosphatidylserine, hypodiploid cells and DNA ladders. HemoHIM appeared to be more protective than HIM-I against $H_2O_2$ induced apoptosis whereas, it exhibited similar activity to HIM-I-P. These results indicated that HemoHIM might be an useful agent for protection against oxidative stress $(H_2O_2)-induced$ apoptosis as well as immune modulation, especially since it is a relatively nontoxic natural product.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.83-89
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• 2001

This study was conducted to test the Cd accumulation and Cd-tolerance of Pisotithus tinctorius(Pt). Pt was isolated from Pinus thunbergii forest in Muan, Chonnam Province in 1997. Pt was cultured on MMN medium supplemented with $CdSO_4{\cdot}5H_2O$ at the final concentration of 0, 0.2, 0.5, 2, and $10{\mu}g/m{\ell}$ for 40 days. Growth rate and tolerance index of the fungus were measured every week, while Cd concentration, superoxide dismutase(SOD), and glutathione reductase(GR) of the fungus were analyzed at the end of the culturing, Pt showed growth reduction in vitro at $2{\mu}g/m{\ell}$ Cd in the medium and almost stopped growth at $10{\mu}g/m{\ell}$ Cd. Tolerance index of Pt decreased with increasing Cd concentration. Cd concentration of Pt was the highest at $10{\mu}g/m{\ell}$ Cd. Activities of SOD did not show significant difference between Cd concentrations, but GR of Pt increased at $0.5{\mu}g/m{\ell}$ Cd, and decreased at $2{\mu}g/m{\ell}$ Cd. Consequently Pt could be called Cd accumulator with a tolerance mechanism to Cd. Their tolerance to Cd were expressed through the higher production of antioxidants such as GR. Pt may be used for revegetation and decontamination of soil polluted by heavy metals.