• Journal of Life Science
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• v.15 no.6 s.73
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• pp.871-878
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• 2005

This experiment was performed to examine the allelopathy effect of allelochemical substance on the crop plants. According to the experiment of the allelochemical substances in Hypochaeris radicata by HPLC, there are the differences at each part of plants. However, it is ascertained that there are 14 kinds of phenolic compounds ingredients that are $\rho$-hydroxybenzoic acid, chlorogenic acid, catechin, caffeic acid, syringic acid, salicylic acid, $\rho$-coumaric acid, ferulic acid, naringin, hesperidin, myricetin, trans-cinnamic acid, quercetin and naringenin. The chemicals like caffeic acid, ferulic acid, and naringenin are commonly included. The result of the chemical experiment shows that there are the differences at each season and part of plants. The leaves in May and blossoms and roots in July contain lots of phenolic acids. It is very high contents such as salicylic acid 2085.6 ${\mu}g/g$ and quercetin 1522.0 ${\mu}g/g$, especially in roots of plants. The result on the growth of crop plants treated by the aqueous extract of Hypochaeris radicata shows that the value of the control group and the test group are same in some cases. However, because the treat value of test group is towel'than that of control group in all items of the experiment, it is cofirmed that the growth of crop plants was inhibited and that the inhibitory effect was increased as its density of treatment was increased. The result of change in quantity shows that there are the differences at each kind of crop plants, but the inhibitory effect was increased as its concentration of treatment was increase with entire. As results, it is confirmed that H. radicata has the allelopathy effect to the crop plants. Especially the inhibitory effect on growth is high in gramineous crop, italian ryegrass and leguminous crop. purple alfalfa.

• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.49-63
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• 2018

This study examines both the announcement effect of corporate real estate acquisitions and sales and long-term stock performance. Also, we analyze long-term stock returns on the basis of the amount and the purpose (business activities, financial activities, etc.) of real estate acquisitions and sales. The major findings are as follow. First, we find that there is no significant announcement effect on the real estate acquisitions. However, the announcement day of real estate sales shows significantly positive abnormal stock returns. Second, we find that both the real estate acquisitions and sales show negative long-term stock performance. We also find the same results from the case where we classify our sample on the basis of the amount and the purpose of real estate acquisitions and sales. Third, the amount of real estate acquisitions is significantly negatively related to long-term stock returns, whereas the relation between firm value and the amount of real estate sales is positive only under the business activities. Overall, long-term stock performance decreases after the announcement day of the real estate acquisitions and sales. This results can be explained by agency theory. Also, we conclude that a decline in stock performance after the real estate sales explain an information signal on financial distress.

• Korean Journal of Childcare and Education
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• v.5 no.1
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• pp.81-101
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• 2009

This study analyzed a total of 37 studies about bi-lingulism and English education as a foreign language published in 8 academic journals in early childhood education or child development fields. Research topics, participants, methods, and variables in the studies were categorized and descriptively analyzed. The research findings which had been statistically investigated were also summarized. The most frequently studied research topics were children's development and English education program exposure, actual conditions of English education in preschool settings and effectiveness of specific English programs for preschool children. However, children's home characteristics were seldom included as research variables and no research investigated so called English preschools. Several studies reported that bi-lingual children may have different language development paths from mono-lingual children but they eventually have comparable language abilities to mono-lingual children. Also some studies reported that, when learning English as a foreign language in school settings, older children can handle more information regarding English than younger children, resulting in better outcomes of older children. Exposure to two languages in early childhood seems to contribute to young children's meta linguistic awareness but the long term effect of English education in early childhood should be further studied. Several English education programs for preschool settings were developed and the effectiveness were investigated. Even though most of them reported that their programs were effective to children's English ability or interests, the results should be carefully interpreted because their research designs and methods were not rigorous.

• Korean Journal of Social Welfare
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• v.59 no.2
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• pp.355-379
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• 2007

This study examined the role of social support and mastery in the effects of hopelessness and depression on suicidal ideation in order to identify elders' suicide and it's related factors. Especially, it focused to find out whether the hopelessness excluding depression has an independent effect on elders' suicidal ideation, and psychosocial factors such as social support and mastery has an interaction effects with elders' hopelessness variables and depression on suicidal ideation. This study recruited 297 elders over 65(older persons in the elder education programs of senior welfare center in Masan, Changwon and Jinhae) and employed a self-administered survey method during January, 2007. The following are the major results of the study. First, the level of hopelessness, depression and suicidal ideation related elders' suicide indicated differences according to their educational level, marital state, income, and their chronical disease numbers. Especially, the lower income and higher chronical disease numbers showed higher level of hopelessness, depression and suicidal ideation among the elder subjects. Second, interaction effects of social support and depression were significant in suicidal ideation, the more level of social support in elder' subjects, the lower the suicidal ideation. While, interaction effects of social support and hopelessness, and mastery and depression/hopelessness in suicidal ideation were not statistically significant. Third, psychosocial factors such as social support and mastery on elders' suicidal ideation have a significant effect when other relevant variables are controlled. From these results, hopelessness is other significant factor predicting suicidal ideation(suicide) among elders. Also, social support and mastery is very significant factor influencing to prevent or decrease suicidal ideation among elders.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.317-326
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• 1996

To know whether pyrazosulfuron-ethyl(PYR) and imazaquin(IMA), known as a acetolactate synthase(ALS) inhibitors, have a same herbicidal action pattern in rice(Oryza sativa) or barnyardgrass (Echinochloa crus-galli), an inhibition pattern and a response characteristics in combination with dymron or butachlor were investigated. In contrast to the phytotoxicity of rice treated with IMA, the one treated with PYR was completely tended to be recovered after 25 days after treatment. Safening effect of dymron against PYR was effectively developed to transplanted-rice, while such an effect was not shown in combination with IMA. In combination with PYR and butachlor, antagonistic effect was observed in both simultaneous or sequential treatment on bamyardgrass, however, additive effect was rather shown in combination with IMA and its activity was dominantly dependent on the first applied compound. $I_{50}$ of PYR and IMA on the ALS extracted from barnyardgrass was $4{\times}10^{-7}$M and $2.8{\times}10^{-6})$M, respectively. Butachlor did not affect their activities on ALS in vitro. These results suggest that PYR and IMA might have a different action each other in the pathway to a final herbicidal activity even though their primary action site is ALS.

• Journal of Food Hygiene and Safety
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• v.31 no.1
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• pp.8-14
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• 2016

The purposes of this study are to confirm ways to reduce bacteria of minimally processed agricultural products, using antibacterial foods that are easily available in home and to improve bacterial hygienic condition of them. We chose garlic-allicin, ginger-gingerol, green tea-catechin, cinnamon-cinnamic aldehyde, wasabi-allyl isothiocyanate as antibacterial foods and their unique antibiotic materials. We confirmed the better washing effect when these antibiotic extracts were used, compared to washing effect by only distilled water. Their antibiosis was proved by statistical processing. PFGE (Pulsed Field Gel Electrophoresis) of Bacillus cereus shows continuous contamination probability of minimally processed vegetables by same product suppliers and the necessity of systematic measures against bacterial contamination.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.527-547
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• 2020

Fish pathogens cause not only economic damages to fish farming but also infectious pathogens known as a zoonotic agent. Since the continued use of antibiotics to control fish pathogens entails side effects, materials of natural origin need to be developed. The purpose of this study is to discover coniferous essential oils with excellent antibacterial effects in order to develop antibiotic alternatives. We have extracted essential oils using hydro-distillation from the leaves of Abies holophylla, Pinus thunbergii, Pinus parviflora, Tsuga sieboldii, and Pinus rigitaeda, which are all Pinaceae family. And, we have evaluated antibacterial activity with the extracted essential oils against Edwardsiella tarda, Photobacterium damselae, Streptococcus parauberis, and Lactococcus garvieae, which are fish pathogens. As a result, the essential oils from A. holophylla and P. thunbergii showed the selectively strong antibacterial activity against E. tarda and P. damselae, which are gram-negative bacteria. From GC-MS analysis, it was identified that main component of A. holophylla essential oils are (-)-bornyl acetate (29.45%), D-limonene (20.47%), and camphene (11.73%), and that of P. thunbergii essential oils is α-pinene (59.81%). In addition, we found three compounds: neryl acetate, (-)-borneol, and (-)-carveol, which are oxygenated monoterpenes. These exist in a very small amount but exhibit the same efficacy as essential oil. Therefore, we expect that A. holophylla and P. thunbergii essential oils having excellent growth inhibitory effect against gram-negative fish pathogens can be used as biological products such as feed additives and fishery products.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.562-572
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• 2020

This study analyzed subjectivity of underachievers on Peer Assisted Learning(PAS) in culinary skills related subject for providing better educational environment through consideration of educational efficiency of particular teaching method. Q Methodology was employed for analysing of responses of a small group of the students. The research found that three types of distinctive structures of responses of the students' subjectivity. The first one was Increase learning effectiveness type(Type1, N=8), the second one was Development of lesson materials for passive students(Type2, N=8), and the last one was Practical self-directed learning needs development(Type3, N=6). From the result, PAS was an effective teaching method for underachievers for encouraging participation of study program, helping to rise self-confidence in subject's tasks, and awareness of self directed learning and additional study on subjects matters. The study, however, found that students could consider themselves as an interruption to other students' study progress, and could feel other students' awareness as a burden. At last, forming a class by deeper consideration on the learning levels of each students and providing additional educational contents for encouraging self directed learning are necessary for the better efficiency for the future.

• The korean journal of orthodontics
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• v.32 no.5 s.94
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• pp.301-312
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• 2002

Treatment timing is a very important factor to consider in treating skeletal Class III patients by means of maxillary protraction. According to the literature maxillary Protraction should be carried out at an early age before puberty. However, no scientific data were presented to support this statement and recent studies supported by statistical data showed disagreement concerning the optimum treatment time of maxillary protraction. Therefore, there is no agreement about the optimum treatment time of maxillary protraction. In this study hand-wrist X-rays were taken from 119 patients and subjects were grouped into prepubertal and pubertal group according to their skeletal maturity. Pretreatment and posttreatment lateral cephalometric X-rays were taken and treatment effects were compared. The average treatment time was 6.5 months for the prepubertal group and 6.1 months for the pubertal group. The obtained results were as follows ; 1. The amount of maxillary forward movement was the same for Pretreatment and pubertal group. 2. The amount of maxillary downward movement was the same for prepubertal and pubertal group. 3. The amount of mandibular downward and backward rotational movement was the same for prepubertal and pubertal group. 4. Dental effects were the same for prepubertal and pubertal group.

• Korean Journal of Social Welfare Studies
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• v.43 no.1
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• pp.203-227
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• 2012

This study analyzes the effect on depression of mutual relational aggression experienced by elderly residents at charity nursing home. It also verifies the mediated effect of adaption by the residents to the nursing home. For this end, the researchers conduct a survey for 182 elderly residents in 7 charity nursing homes in Seoul and Kyonggi Province. The statistical methods for the analysis were SPSS version 18.0 and AMOS 7.0program. Following are the findings. First, there turns out to be no statistical significant effect between mutual relational aggression and depression. Second, elderly residents' adaption to the nursing home is proved to serve as a mediated effect between mutual relational aggression and depression. In other words, the more the relational aggression, the more difficult it is for residents to be adapted to the nursing home, and the more depressed the residents are prone to be. Following are suggestions based on the findings. First, nursing home staffs need to establish a system in consideration both of relational aggression and of resident's adaption, to reduce its elderly residents' consequential depression. Second, nursing home staffs need to take measures to help adaption of new residents to prevent or reduce their depression. For example, new residents can be allowed to bring their belongings to the nursing home as much as they want and the nursing home can stand. Third, nursing homes also need to develop programs to prevent or reduce any negative relation, including bullying or casting out, among peer residents in the nursing home.