• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.261-270
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• 2014

This study was conducted to establish the method for preserving chicken primordial germ cells (PGCs) that enables long-term storage in liquid nitrogen ($LN_2$) for developmental engineering or preservation of species. The purpose of this study is to clarify the effects of simple freeze-thaw treatment on viability of PGCs in chickens and to the optimal protocol for PGCs freezing. PGCs obtained from the germinal gonade of an early embryos of 5.5~6 day (stage 28) of Isa Brown, Korean Ogye (KO), White Leghorn and Commercial breeds, using the MACS method were suspended in a freezing medium containing a freezing and protecting agents (e.g. dimethyl sulfoxide (DMSO), ethylene glycol (EG) and propylene glycol (PG)). The gonadal cells, including PGCs, were then frozen in 1 of the following cryoprotectant treatments : 2.5%, 5%, 10%, 15%, and 0% cryoprotectant (DMSO, EG, PG) as a control. Effects of exposure to simple freezing, with different concentrations of the cryoprotectant solution, were examined. After simple freezing, the viability of PGCs after freeze-thawing was significantly higher for Commercial breeds ($88.7{\pm}2.4%$) than KO ($85.1{\pm}0.4%$), Isa Brown ($84.6{\pm}0.2%$) and White Leghorn ($85.9{\pm}0.1%$) (p<0.05) using 10% EG cryoprotectant. Therefore, these systems may contribute in the improvement of cryopreservation for a scarce species in birds preservation. This study established a method for preserving chicken PGCs that enables systematic storage and labeling of cryopreserved PGCs in liquid ($LN_2$) at a germplasm repository and ease of entry into a database.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.773-788
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• 2017

This study was carried out to investigate the damage patterns, the occurrence and migration time of Pseudococcus comstocki and in order to improve the control effect of organic agricultural materials (OAMs). The experiment was carried out at Okcheon's organic vineyard ($2,500m^2$, sandy loam, manure) where planted 8~9 year old 'Muscat of Alexandria' vines. The comstock mealybug's migration to grape clusters occurred from the middle of July, and produced eggs in the grape clusters from the end of July, and the density of the comstock mealybug was highest at $0.6cm^2$ in late August. The number and fruit damage of comstock mealybug in eco-friendly vineyards were higher than in conventional culture vineyard. And the marketability of green variety grape was more damaged from comstock mealybug than the black variety grape. Toxicities of 8 OAMs were evaluated to comstock mealybug at the recommended concentration. As a results, Lightyellow sophora and Derris extracts exhibited strong insecticidal activity with 100% mortality. When the Lightyellow sophora extract was uniformly distributed on the vine from early-July to mid-July, fruit damage reduction rate was 96.2% and 84.6%, respectively. So commercial grapes could be harvested. Therefore, it was considered to be effective to reduce fruit damage by controlling in early - late July (the green stage) when the comstock mealybug migrated to grape clusters in the vine greenhouse. In the future, it will be necessary to study the effect of external exposure time and momentum on the control of OAMs.

• 한국해양학회지
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• v.30 no.5
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• pp.390-402
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• 1995

Bimonthly sampling was carried out over the period February 1983 to April 1985 at two stations in Kwang-yang Bay, Korea, in order to study the temporal changes of benthic ploychaete communities. In addition, an important focus of the study was the large-scale reclamation and dredging operations that were taking place for industrial purposes during the study period. The muddy station, located on the main channel, showed high mud content (94%), whereas the sandy station, situated on the north channel of Myodo, demonstrated mud content of 42%. At the muddy station, the number of species and individuals were highest in the early sampling stage, but markedly declined in October 1983, and then gradually increased as in the early state. At the sandy station, the number of species highly oscillated during the entire period. The density was affected by the pectinated Lagis bocki showing particulary high density in February 1983 and 1984. However, the high density in the winter time did not occur in February 1985. The analysis of similarities and clusterings between communities were carried out to evaluate temporal changes in community structure. Significant changes occurred during the study period in the community structures at both stations, but each maintained different patterns of species dominance over time. At the muddy station, this transitionary phase was found in October 1983 but in December 1984 at the sandy station. Comparisons with earlier communities suggest that faunal changes in the dominant species composition occurred from Lumbrineris longifolia to Heteromastus filiformis over this time period. The colonization of this opportunistic pioneer, H, filiformis, seems to manifest environmental disturbances in this bay area.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.112-119
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• 2012

This study investigated the diel and tidal distributions of the two mysids, Archaeomysis kokuboi and Acanthomysis nakazatoi, in relation to their growth stages in the sandy surf zone of Yongil Bay, located on the southeastern part of Korean Peninsula. Sampling was conducted with a sledge net at every two hours for almost 24 hours at three sites: water edge, water surface and sand bottom both in 1-m deep water areas. The abundance of Archaeomysis kokuboi juveniles was too low to count both in day and night samples. While there was no difference in immature A. kokuboi abundance between day and night in the bottom or water edge, that at the water surface was significantly higher at night than daytime. The abundance of A. kokuboi adults, especially of males, in the bottom was significantly higher in daytime than night and no individuals appeared to the water surface either day or night. In comparison, the abundance of Acanthomysis nakazatoi juveniles between day and night did not differ significantly at all the three sites, with the highest number being distributed in the bottom. The abundance of immatures between day and night also did not differ significantly and no individuals appeared to the water surface either day or night. The abundance of A. nakazatoi adults, especially females, in the bottom was significantly higher at night than daytime and there was no significant difference in abundance between day and night in the other sites. There was also no significant difference in abundances of the two species between ebb and flood tides, except for A. kokuboi immatures which appeared significantly more during the ebb tides at the water surface. Overall, the distribution of the two sympatric species, A. kokuboi and A. nakazatoi, was not the same in the sandy surf zone. Its difference seems to depend on their stages of growth, and the change in their abundance may be influenced more by diurnal rhythms than tidal effects. The population density of A. nakazatoi in the sandy surf zone was much higher than that of A. kokuboi, and relatively higher densities in all growth stages of the former were found in the sandy bottom ranging from juveniles to adults. These results indicate that A. nakazatoi has exceedingly better ability of sand burrowing even from the juvenile stage, and thus is an ecologically better adapted species in the sandy surf zone than another sympatric species, A. kokuboi.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.2
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• pp.89-103
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• 2013

National demands for the ocean forecasting system have been increased to support economic activity and national safety including search and rescue, maritime defense, fisheries, port management, leisure activities and marine transportation. Further, the ocean forecasting has been regarded as one of the key components to improve the weather and climate forecasting. Due to the national demands as well as improvement of the technology, the ocean forecasting systems have been established among advanced countries since late 1990. Global Ocean Data Assimilation Experiment (GODAE) significantly contributed to the achievement and world-wide spreading of ocean forecasting systems. Four stages of GODAE were summarized. Goal, vision, development history and research on ocean forecasting system of the advanced countries such as USA, France, UK, Italy, Norway, Australia, Japan, China, who operationally use the systems, were examined and compared. Strategies of the successfully established ocean forecasting systems can be summarized as follows: First, concentration of the national ability is required to establish successful operational ocean forecasting system. Second, newly developed technologies were shared with other countries and they achieved mutual and cooperative development through the international program. Third, each participating organization has devoted to its own task according to its role. In Korean society, demands on the ocean forecasting system have been also extended. Present status on development of the ocean forecasting system and long-term plan of KMA (Korea Meteorological Administration), KHOA (Korea Hydrographic and Oceanographic Administration), NFRDI (National Fisheries Research & Development Institute), ADD (Agency for Defense Development) were surveyed. From the history of the pre-established systems in other countries, the cooperation among the relevant Korean organizations is essential to establish the accurate and successful ocean forecasting system, and they can form a consortium. Through the cooperation, we can (1) set up high-quality ocean forecasting models and systems, (2) efficiently invest and distribute financial resources without duplicate investment, (3) overcome lack of manpower for the development. At present stage, it is strongly requested to concentrate national resources on developing a large-scale operational Korea Ocean Forecasting System which can produce open boundary and initial conditions for local ocean and climate forecasting models. Once the system is established, each organization can modify the system for its own specialized purpose. In addition, we can contribute to the international ocean prediction community.

• Korean Security Journal
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• no.14
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• pp.517-534
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• 2007

Since the beginning of human society, there have always been struggles and competitions for survival and prosperity, terrorism is not a recent phenomenon, however in modern times it has progressed to reflect the advances in civilization and power structures. At the time of the 9.11 terrorist attacks in the U.S. A., a new world order was in the process of being established after the breakdown of the Cold War era. The attacks drove both the Western and the Islamic worlds into heightened fear of terrorism and war, which threatened the quality of life of the whole mankind. Through two war campaigns against the Islamic world, it seems the U.S. has been pushing its own militaristic security road map of the Greater Middle East democratic initiative, justifying it as a means to retaliate and eradicate the terrorist threats towards themselves. However, with its five-year lopsided victories that cost the nation almost four thousand military casualties, and the war expenses that could match the Vietnam war, the U.S. does not yet seem to be totally emancipated from the fears of terrorism. Terrorism, in itself, is a means of resisting forced rules a form of alternative competition by the weak against the strong, and a way of expressing a dismissive response against dictatorial ideas or orders which allow for no normal changes. Intrinsically, the nature of terrorism is a reaction opposing power logics. Confronted with the absolute military power of the U.S., the Islamic strategies of terrorism have begun to rapidly evolve into a new stage. The new strategies take advantage of their civilization and circumstances, they train and inspire their front-line fighters on the Internet, and issue their orders through the clandestine network of the Al Qaeda operatives. These spontaneously generated strategies have been gained speed among the second, and third Islamic generations, many of whom are now spread throughout western societies. This represents a failure of the power-driven, one-sided overseas security initiatives by the U.S., and is creating a culture of fear and distrust in western societies. It is feared that the U.S. war campaigns have made the clash of religions far worse than before, and may ever lead to global ethnic separations and large-scale population movements. Eventually, it may result in the terrorist groups, enlarged and secretly supported by the huge sums of oil money, driving all mankind into a series of irreparable catastrophes.

• Korean Journal of Social Welfare
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• v.57 no.3
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• pp.305-335
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• 2005

This paper is a result from validation study for SPDA(A Screening Scale For Potential Drug-use Adolescents) created in 2003 and newly developed during 2004. SPDA aims to screen adolescents in their early stage of drug-use and to help practitioners make a preventive approach for the adolescents. 4307 junior and senior high school students were selected as primary research subjects by stratified and quota sampling methods. 305 adolescents on probation were also selected as a comparison group and asked to answer the same questionnaire. Reliability for SPDA recorded 0.914, which proved to be better than previous year's (0.898). Exploratory and confirmatory factor analyses to test construct validity proved that SPDA could be divided into 7 factors and that each factor structure of SPDA could be a proper measurement model with high level of fitness and factor loadings. Discriminant analysis to test predictive validity confirmed that SPDA could classify the adolescents excellently by the frequency of drug-use, with hit ratio of 86.6 percent(78.8% and 87.4% for junior and senior high school students respectively). For concurrent validity test, Hare Home Self-Esteem Scale, Hare School Self-Esteem, Zuckerman-Kuhlman Sensation-seeking Scale were employed to find correlation with SPDA and all the three scales had significant Pearson correlation coefficients with SPDA. Known-groups validity test indicated that SPDA had an adequate power to classify out adolescents on probation from those in schooling, with a hit ratio of 71.8 percent. Cut-off point to detect adolescents with high risk of substance use was 77, which indicated approximately T score, 55 (0.5 SD), satisfying sensitivity, specificity, and efficiency criteria.

• Tuberculosis and Respiratory Diseases
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• v.52 no.5
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• pp.519-528
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• 2002

Background : Steroid therapy has been shown to improve the clinical outcome in acute respiratory distress syndrome (ARDS) patients with histological evidence of fibroproliferation in the lung tissue and no identifiable source of infection. Because the histopathological features of acute interstitial pneumonia(AIP) are identical with that of ARDS, early steroid therapy was used in AIP patients who had histological evidence of fibroproliferation in the lung tissue and no identifiable source of infection. We analyzed seven years of our experience to evaluate the efficacy of early steroid therapy in AIP. Materials and Methods : A retrospective review was performed on AIP patients who received steroid therapy within 7 days of mechanical ventilatory support in Dankook university Hospital between May 1995 and May 2002. AIP was diagnosed clinically by ARDS without a known cause of the etiology and pathologically by a lung biopsy showing a fibroproliferative stage of diffuse alveolar damage. The clinical response and physiologic parameters were evaluated during steroid therapy. Results : Five AIP patients received intravenous methylprednisolone (1-2 mg/kg every 6 hours) after $0.6{\pm}1.7$ days of mechanical ventilatory support. Lung biopsies were performed after $1.8{\pm}1.4$ days of mechanical ventilatory support. Four patients(80%) survived and were extubated after $2.8{\pm}0.4$ days of steroid therapy with improvement in the $PaO_2/FiO_2$ ratio ($127.4{\pm}10.0$ at day 0 to $223.8{\pm}37.6$ at day 7) by steroid therapy. However, one patient(20%) died of respiratory failure after 15 days of steroid therapy. Conclusion : Early steroid therapy sppears to be beneficial in AIP patients without evidence of infection. However, as our study group was too small, further large scale studies to define the effectiveness of steroids are required.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.9
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• pp.63-73
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• 2015

This work proposes a 2-channel time-interleaved (T-I) 10b 120MS/s pipeline SAR ADC minimizing offset mismatch between channels without any calibration scheme. The proposed ADC employs a 2-channel SAR and T-I topology based on a 2-step pipeline ADC with 4b and 7b in the first and second stage for high conversion rate and low power consumption. Analog circuits such as comparator and residue amplifier are shared between channels to minimize power consumption, chip area, and offset mismatch which limits the ADC linearity in the conventional T-I architecture, without any calibration scheme. The TSPC D flip-flop with a short propagation delay and a small number of transistors is used in the SAR logic instead of the conventional static D flip-flop to achieve high-speed SAR operation as well as low power consumption and chip area. Three separate reference voltage drivers for 4b SAR, 7b SAR circuits and a single residue amplifier prevent undesirable disturbance among the reference voltages due to each different switching operation and minimize gain mismatch between channels. High-frequency clocks with a controllable duty cycle are generated on chip to eliminate the need of external complicated high-frequency clocks for SAR operation. The prototype ADC in a 45nm CMOS technology demonstrates a measured DNL and INL within 0.69LSB and 0.77LSB, with a maximum SNDR and SFDR of 50.9dB and 59.7dB at 120MS/s, respectively. The proposed ADC occupies an active die area of 0.36mm2 and consumes 8.8mW at a 1.1V supply voltage.

• Journal of Mushroom
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• v.2 no.1
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• pp.15-20
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• 2004

Pleurotus ostreatus, the oyster mushroom, is one of the most widely cultivated and important edible mushrooms in the world. In order to study the developmental process of P. ostreatus and its regulatory mechanism, a new culturing method needs to be established for inducing the fruiting body and sporulation in the laboratory. In this study, we have examined whether the fruiting body of P. ostreatus can be formed on the plastic petri dish which are commonly used for cell culture in the laboratory. The strain was cultured on $60{\times}15mm$ plastic petri dish with potato dextrose agar media at $28^{\circ}C$ for mycelial growth and then at $18^{\circ}C$ for the formation of primordia and fruiting bodies within plant growth chamber. The development of primordia into fruiting bodies was achieved on cultured dishes under air ventilation. At the primordia stage, the normal formation of fruiting body was blocked by sealing the plastic dish with parafilm. The periods requiring for the formation of primordia and fruiting bodies were examined on the dish culture. About 96% and 76% of cultured samples formed primordia and fruiting bodies under the optimal conditions during ten weeks of culture, respectively. These culturing periods, however, were changed by the mechanical injury treatment to mycelia. As other factors affecting the fruiting body formation, the effects of light and cold shock have been tested. No fruiting formation was observed on the cultured dishes under the dark. The cold shock treatment by storing cultured dishes for one day at $4^{\circ}C$ did not have any significant effects in the fruiting body formation. Spores of fruiting bodies acquired from the petri dishes could be germinated on culture media at $28^{\circ}C$. These results suggest that the fruiting bodies of P. ostreatus can be formed on the experimental petri dish and this dish-culturing method is useful for understanding of the developmental process of P. ostreatus in the laboratory. Furthermore, the dish-culturing method is able to shorten the life cycle of P. ostreatus without requiring large area and expensive device.