• Journal of Plant Biotechnology
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• v.35 no.1
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• pp.81-86
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• 2008

This study describes conditions for plant regeneration from protoplasts-derived from embryogenic callus of satsuma mandarin. Plants were generated via somatic embryogenesis. Protoplasts isolated directly from nucellar callus induced from immature ovule of satsuma mandarin cv. Okitsu (Citrus unshiu Marc.) were cultured in 0.6M $BH_3$ medium. Cell division and plating efficiency were affected by protoplast culture method. The liquid over solid method was the most effective for formation of microcalli. Most of microcalli grew rapidly and transferred onto embryoid formation medium. Optimum embryoid formation medium was MT medium containing 1.5 g/L malt extract, 0.146 M sucrose and the medium for plantlet regeneration was MS medium containing 0.09M sucrose, 1.0 mg/L $GA_3$. No differences were noticed in growth habits and leaf characters such as shape, thickness, and colour between protoplast-derived plants and nucellar seedlings. This plant regeneration system from protoplasts-derived from embryogenic callus provides an alternative way for producing new scion and rootstock cultivar from citrus species which can not be crossed.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.25 no.2
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• pp.42-53
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• 2020

In this study, heavy metal in road-deposited sediments (RDS) and marine sediment around Gwangyang Bay area have been investigated to assess the pollution status of metals and to understand the environmental impact of RDS as a potential source of metal pollution. Zn concentration for <63 ㎛ size fraction was the highest (2,982 mg/kg), followed by Cr, Ni, Pb, Cu, As, Cd, and Hg. Metal concentrations in RDS increased with decreasing particle size and relatively higher concentrations were observed around the metal waste and recycling facilities. For particle size in RDS smaller than 125 ㎛, EF values indicated that Zn was very high enrichment and Cr, Cd, Pb were significant enrichment. The concentrations of metals in marine sediments were mostly below the TEL value of sediment quality guidelines of Korea. However, the Zn concentrations has increased by 30~40% compared to 2010 year. The amounts of Zn, Cd and Pb in less than 125 ㎛ fraction where heavy metals can be easily transported by stormwater runoff accounted for 54% of the total RDS. The study area was greatly affected by Zn pollution due to corrosion of Zn plating materials by traffic activity as well as artificial activities related to the container logistics at Gwangyang container terminal. The fine particles of RDS are not only easily resuspended by wind and vehicle movement, but are also transported to the surrounding environments by runoff. Therefore, further research is needed on the adverse effects on the environment and ecosystem.

• Management & Information Systems Review
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• v.34 no.2
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• pp.113-130
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• 2015

This study considers the relation between firms' earnings management and credit rating. Unlike preceding papers only focusing earnings management by accrual(thereafter, AM), this paper examines the effect of accrual earnings management(AMs) and real earning management(thereafter, RM) on credit rating. RMs have more negative effects on firms' forward cash flow generation abilities and long term operating performances than AMs. So, RMs are more negative signals for credit analysts than AMs. But credit analysts have much difficulty in seeing through RM, because if credit analysts want to find out RMs, they have to understand firms' internal operating activities, cost structures, receivables collection practices, and review whether profit distortions are due to abnormal change of them. Sample of this study consists of 2,150firm-year data listed companies from 2002 to 2010. Empirical evidence shows that AMs and RMs are negatively related to credit rating. This result implies that credit analysts see through AMs and RMs in interpreting financial informations, that is to say, they discount credit rating in considering level of earnings management that consist of real activity and accrual earning management. This paper also finds that RMs are more negatively related to credit ratings than AMs. This result suggests that credit analysts don't take RMs into account in credit rating process as much as AMs.

• Journal of dental hygiene science
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• v.14 no.1
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• pp.29-34
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• 2014

The purpose of this study was to evaluate the influence of low temperature degradation (LTD) on the bonding strength of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP). The push-shear bond test method was used to investigate the core-veneer bonding strength of industrially manufactured Y-TZP core ceramic and manufacturer recommended veneering ceramic. Four groups from ceramic-zirconia specimens (n=28; n=7 per group) were assigned into four experimental aging conditions, namely storage in an autoclave at $134^{\circ}C$ for 0, 3, 5, 10 hours. Bonding strength was obtained using a universal testing machine with crosshead speed 0.5 mm/min. Data were statistically analyzed using one-way ANOVA and Tukey's test (${\alpha}=0.05$). In bonding strength test, the group which was treated with LTD showed lower bonding strength than no treated group. The ceramic-zirconia bonding strength was affected by LTD (p<0.05). Digital microscope examination of the fracture surface showed mixed failures with adhesive and cohesive types in LTD with treated Y-TZP groups.

• Korean Journal of Plant Taxonomy
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• v.44 no.1
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• pp.39-50
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• 2014

Phylogenetic positions of Sedirea and Neofinetia were addressed using the chloroplast matK and the nuclear ITS sequences. We also evaluate the usefulness of the makers for the identification of species and localities. Sedirea and Neofinetia form an independent monophyletic genus, respectively, in both matK and nuclear ITS trees. The sister genus of the Neofinetia was Vanda in both trees. In addition, our trees support the separate recognition of the Neofinetia from Vanda rather than the inclusion of Neofinetia into Vanda. The sister group of the Sedirea was (Dimorphorchis(Pteroceras(Saccolabiun+Phalaeonopsis))) clade. The Dimorphorchis was one of the most probable sister genus to the Sedirea. The sister group relationship between Sedirea and Aerides was suggested by their similar morphology, but not supported in molecular trees. The identification of species and localities of Neofinetia was possible using our two molecular markers. However, several pseudo-gene sequences are discovered from the public data base. In addition, the horizontal gene transfer of chloroplast genomes is frequent events in orchid hybrids. Therefore, we need a careful evaluation for the data prior to systematic use. Generation of sequence data from multiple accessions of a species may helpful to reduce these types of error.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.99-103
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• 2005

Nitrogen content of liquid manures varies from $3g\;kg^{-1}\;to\;7g\;kg^{-1}$ according to the collecting seasons. The application effects of liquid manure on the yield of rice are the best in LPM+LPM treatment, although the lodging of crops increased and the quality of rice is deteriorated. When application with LPM+CF treatment and CF+LPM treatment showed no difference in rice yield and quality, compared with CE+CF treatment. Therefore, use of liquid manure on farmland should be limited as once per year during cultivation duration and liquid manure is fully fermented during 6 months at least in order to decrease the damage of crops by application of unmatured liquid manure. Also, application amount of liquid manure should be carefully determined by considering the mineral (especially nitrogen) contents of liquid manure and the recommended fertilizer levels for various crops.

• Korean journal of communication and information
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• v.60
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• pp.5-27
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• 2012

The purpose of this study is to explore the journalist Song Kun-Ho's ideas of Korean Journalism. The journalist Song Kun-Ho was born in 1926 and passed away in 2001. He became a reporter in 1953 when he was a student at department of law of Seoul National University. He has worked for several media and resigned the executive editor at the Dong Ah Ilbo in 1975. At that time, while many reporters of the Dong Ah Ilbo struggled for the freedom of the press, he tried to protect reporters and independence of media. After his resignation of the executive editor, he wrote many columns and several books for Korean nationalism and the democracy of journalism. Instead of working for the authoritarian military regime, he chose a lonely and rough life as an intellectual journalist in action. Finally, he, as a president, established the Hankyoreh daily newspaper which was funded by tens of thousands citizens. He passed away in 2001. His ideas of Korean journalism are nationalism, democracy, and independency. These ideas are very important to restore democratic journalism which has been at risk during the Lee Myung-bak administration.

• Korean journal of communication and information
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• v.48
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• pp.90-108
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• 2009

While the term of the institution as social manifestation has been discussed intensively through various theoretical approaches over the last few years in Social Sciences, such a debate has been missing so far in Communication Sciences. This paper attempts a theoretical discussion about the media as an institution in the field of Communication Sciences by applying the theory of organizational sociological neo-institutionalism. This research started out with the question which influence exerts the media on organizations and participants. The media is understood as an institution in the sense of permanent monitoring systems which create a) normative expectations b) which become stronger in order to assert such normative expectations c) the norms are applied by the participants d) in this application process, the participants accept the organizations, look primarily for the chosen paragraphs and exert an influence to change the norms. Organizations orient themselves at the institutional rules, because this way, they want to gain legitimacy and support. The media unfold their influence on organizations through certain obligations in addition to the pressure of the participants who deal with the organization and the media. Thus, media cannot exert influence independent from the organizationbut the participants accept the situation, which is generated by the many conflicting processes within the organization, they analyse them and transfer them.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.369-373
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• 2001

The congenital missing of mandibular second premolars is among the common dental anomaly in children. When a second premolar is diagnosed as congenitally missed, we should consider many factors influencing the treatment plan such as patient's age, states of roots of 2nd primary molar, degree of crowding, skeletal growth pattern, facial profile, procumbency of the incisor and lower facial height, etc. The mineralization of the second premolars begins in the majority of cases at the age of $2\sim2\frac{1}{2}$ years, but this period varies more widely than those for other permanent teeth. Also, mandibular second premolars show the greatest variations in differentiation and calcification. For this reason, aplasia of this group of teeth cannot be diagnosed at early age and with the same degree of certainty. From the clinical studies with 2 cases and some literature review on late development of second premolars, it could be summarized as follows : 1. The 2 cases showed marked delay in the development of mandibular second premolars. 2. After the crypt formation, the speed of calcification seemed nearly normal, suggesting that the delay was due to differentiation rather than calcification. 3. When one is encountered with similar conditions, it would be desirable to consider the possibility of delayed tooth development.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.624-633
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• 2017

Korean society has begun to transition toward a multicultural society, and the rate of change is increasing. If so, is our society ready to meet this change of society? It is true that Korean society has been dominated by the paradigm of 'monoethnicity', and traditionally has been regarded as a virtue to maintain this view. However, it is worth noting that isolated single cultures have historically met a disastrous end. On the contrary, people who have adapted their culture and style have enjoyed prosperity. Korean society has hovered between embracing and rejecting the flow of change, and has finally accepted them to choose the way to go on a multicultural society living together. However, it seems that the changes in policy have not kept pace with recent changes in society. Despite the fact that the most efficient way to change perception is to establish and implement appropriate educational policies promoting multiculturalism, most education in Korean society has focused on the closed form of education, for the influx people, not having been made proper education for most of Korean people who should actually accept them and get along with them. Therefore, they have been striving for an assimilated viewpoint that simply get it transformed into Koreanized, not understanding and accepting them as they are. However, this type of education cannot lead a Korean multicultural society in the right direction. We objectively examined the reality of Korean society facing this crisis and presented policy changes regarding multicultural education through examining the case of France, which experienced a similar crisis prior.We are going to present the direction of change in multicultural education through the case of France which has experienced similar crisis before us by examining the reality of Korean society facing the crisis like this.