• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.535-539
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• 2016

The prevalence of pathogenic bacteria such as Streptococcus parauberis (Sp), Streptococcus iniae (Si), and Edwardsiella tarda (Et) in flounder fish farms in Jeju Island and their management by gallium treatment was studied. Sp, Si, and Et were found to exhibit a low rate of cell growth and high biofilm formation. Hence, in the present study, cell growth and biofilm formation were measured spectrophotometrically 72 h after the addition of different concentrations of gallium (2, 4, or 8 mg/ml). In addition, cell death was measured by resazurin and propidium iodide staining assays. The results showed that bacterial cell death increased and biofilm formation decreased with an increasing concentration of gallium. Hence, the present study signifies that the use of gallium against bacterial pathogens could be useful for disease management in flounder farms.

• Journal of the Korean Society for information Management
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• v.34 no.3
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• pp.251-267
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• 2017

This study aimed to analyze open access features of 1,890 Korean scientific journals registered in the Korea Citation Index (KCI). To this end, this study classified open access features of the target scientific journals into two main aspects, free access and free redistribution. The analysis results indicated that the target scientific journals had strong free access aspects. Based on websites, 67% of the target scientific journals allowed for free access without a login process and based on free database, 48% provided free access. On the other hand, the target scientific journals had weaker free redistribution aspects compared to their free access aspects. Only 14% of them offered the CC (creative commons) license. Another finding was that there were clear differences in open access aspects by academic field. Medicine, pharmacy, natural science, agriculture, fisheries, oceanography, and engineering had stronger open access aspects than humanities, sociology, arts, physical education, and interdisciplinary science. It appears that the difference was caused by the presence or absence of organizations supporting distribution of scientific journals of the fields concerned. To narrow the gap, it is recommended that the open access governance system is established to set up open access policies for Korean scientific journals regardless of academic fields and to support them.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.1
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• pp.56-67
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• 2018

With the introduction of the maritime safety supervisor system in Korea following the passenger vessel Sewol accident, the safety control system for coastal vessels has been reinforced. A maritime safety supervisor performs marine accident prevention activities by offering periodical or occasional guidance and supervision. When a deficiency is found during guidance or supervision sessions, an order for improvement is issued to rectify the problem by such measures as supplementation or replacement of vessel facilities, improvement of work hours and working conditions for employees, educational and training programs for executives and employees, or the improvement of other affairs relating to maritime safety control. However the present order for navigation suspension by a maritime safety supervisor is limited solely to supplementation or replacement. For this reason, orders for navigation suspension against other facilities is impossible, even if a serious deficiency that could lead to a marine accident such as poor cargo loading conditions or unqualified crew is identified. Therefore, the order for vessel navigation suspension to secure seaworthiness should be expanded to include cargo loading/unloading operations, certificates and documentation, maritime safety management systems, and human elements including emergency drills and working conditions, in addition to the supplementation or replacement of vessel facilities that exists.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.576-585
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• 2020

This study quantitatively investigated the increase in ballasting time through numerical calculations when an ultraviolet (UV) ballast water management system (BWMS) is installed on an existing vessel. The calculation results indicate that the ballasting time of a gas carrier having 55,000 dead weight tonnage was 2.152 hours without installation of the UV BWMS and implementation of a flow control function. Ballasting time increased by 14.2% after installing the UV BWMS, and it increased by 20.4% with both its installation and implementation of a flow control function. If actual conditions are taken into account, ballasting time after installing the UV BWMS is estimated to increase by at least 30% compared with current ballasting time. Therefore, when concerned parties select a UV type BWMS, it is advisable for them to minimize ship operation losses from an increase in ballasting time by considering the capacity of the actual ballast pumps on board and the flow energy loss of the UV BWMS. Additionally, it is recommended that a BWMS with larger capacity, larger pipes, and pipes with inside coatings be used to minimize the increase in ballasting time after installation of the BWMS.

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.129-137
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• 2013

This study was conducted to find out the changes of survivorship, respiration and organ structure of Mactra veneriformis exposed to copper (Cu). Experimental period was four weeks. Experimental groups were composed of one control condition and three copper exposure conditions (0.025, 0.050 and 0.100 mg/L). The results of the study confirmed that copper induces reduction of survival rate and respiration rate and histopathology of organ structure of the bivalve. In the copper concentration of 0.100 mg/L, mortality was 100% after Cu exposure of 3 weeks. Respiration rate was observed exposure groups lower than control decline by 75%. Histological analysis of organ system illustrated expansion of hemolymph sinus, disappearance of epidermal layer and degeneration of connective tissue layer of the mantle. Also, histological degenerations as epithelial necrosis and hyperplasia of mucous cells are recognized in the gill and it was observed expansion of hemolymph sinus, disruption of epithelial layer, decrease of mucous cell and degeneration of connective tissue layer in the foot. In the digestive diverticulum, it was showed atrophy of basophilic cell and degeneration of epithelial cell in the digestive tubules, and as the concentration of copper increased the accumulation of lipofuscin increased.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.7
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• pp.722-728
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• 2015

The demand for shipboard energy management is expected to gradually increase based on ship energy efficiency management plans (SEEMPs), which have been in use since January 1, 2013. Therefore, the fuel consumption of the main engine, which occupies the greatest portion of the energy used, along with elements related to the engine power, should be strictly monitored. There are many different methods for indicating the engine power. However, this study performed an experiment to monitor the status of a ship's engine power in real time using an encoder and a proximate switch, which are economical to purchase and easy to install. In the experiment, the angular velocity during one cycle of a two-stroke low-speed engine was measured, and the measured data were converted to the torque fluctuation. The angular velocity during an abnormal firing condition in the cylinder was also measured, and the torque fluctuation as a result of a misfire was considered. The results were compared with sea trial data to determine the reliability. In this study, the status of the engine power was determined using the torque fluctuation of the main engine in an operating ship.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.4
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• pp.61-70
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• 2019

This study aimed to investigate the physicochemical characteristics of fish meal, bone meal, and sesame oil cake, which are readily available by-products from agriculture and fisheries, during the process of liquid fertilizer fermentation, and to examine the effects of liquid fertilizer application on seed germination and growth of tomatoes. During processing the fermentation for liquid fertilizers by using fish meal, bone meal, and sesame oil cake liquid fertilizers, the pH of the fertilizer increased in the order of bone meal > fish meal > sesame oil cake, and the concentration increased rapidly up to 30 days in all types of liquid fertilizer. The nitrogen content of the liquid fertilizers increased as fermentation progressed in the order of fish meal > bone meal > sesame oil cake. The phosphorus content increased as fermentation progressed and the highest was 1.0 % in the liquid fertilizer of sesame oil cake. The germination rate and its index of radish seeds were compared for different dilutions of each of the liquid fertilizers. Excluding the 10-fold dilution of the fish meal and oil cake liquid fertilizer, all the treatment groups showed a germination rate ≥ 95 % and the germination index tended to increase with dilution rate of liquid fertilizers. For responses of tomato growth, there were no significant differences among the liquid fertilizer treatment groups; however, the organic content, microbial density, and microbial biomass C in the soil were higher than chemical fertilizer treatment. These results demonstrated that there were differences in the characteristics of liquid fertilizers depending on the materials used, and that liquid fertilizer can be used for nutrition management for the organic crop cultivation.

• Parasites, Hosts and Diseases
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• v.52 no.3
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• pp.305-310
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• 2014

Ascidian soft tunic syndrome (AsSTS) caused by Azumiobodo hoyamushi (A. hoyamushi) is a serious aquaculture problem that results in mass mortality of ascidians. Accordingly, the early and accurate detection of A. hoyamushi would contribute substantially to disease management and prevention of transmission. Recently, the loop-mediated isothermal amplification (LAMP) method was adopted for clinical diagnosis of a range of infectious diseases. Here, the authors describe a rapid and efficient LAMP-based method targeting the 18S rDNA gene for detection of A. hoyamushi using ascidian DNA for the diagnosis of AsSTS. A. hoyamushi LAMP assay amplified the DNA of 0.01 parasites per reaction and detected A. hoyamushi in 10 ng of ascidian DNA. To validate A. hoyamushi 18S rDNA LAMP assays, AsSTS-suspected and non-diseased ascidians were examined by microscopy, PCR, and by using the LAMP assay. When PCR was used as a gold standard, the LAMP assay showed good agreement in terms of sensitivity, positive predictive value (PPV), and negative predictive value (NPV). In the present study, a LAMP assay based on directly heat-treated samples was found to be as efficient as DNA extraction using a commercial kit for detecting A. hoyamushi. Taken together, this study shows the devised A. hoyamushi LAMP assay could be used to diagnose AsSTS in a straightforward, sensitive, and specific manner, that it could be used for forecasting, surveillance, and quarantine of AsSTS.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.645-654
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• 2015

This paper attempts to quantitatively assess the conservation value of Ellobium chinense (EC), which belongs to the endangered marine species designated by Ministry of Oceans and Fisheries. To this end, we apply the contingent valuation (CV) method, an economic technique of valuing a non-market goods such as EC. A national survey of randomly selected 1,000 households was administered in order to derive the public's willingness to pay (WTP) for conserving EC. One-and-one-half-bound model was adopted to elicit the WTP responses and a spike model was employed to deal with the zero WTP responses. The results show that the conservation value of EC is estimated to be 2,346 won per household per year that is statistically significant at the 1% level. Expanding the value to the national population gives us an annual value of 43.8 billion won. We can judge that the Korean people are willing to pay a significant amount to conserve EC.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.123-129
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• 2012

Cabotage means transportation of cargoes or passengers between two points within same country by vessel or aircraft which registered to foreign country. Cabotage regulation has justified by the protectionism in economic aspect and by national security in the defence of a country, thus most world's major countries including United States of America, Japan and European Union(outside EU) are executing cabotage. Even though Korean's controlled fleet ranked to 5th in the world, shortage and ageing of Korean domestic seafarers came to the restricted factor in the Korean domestic shipping. Resultingly Korean government permitted 530 Myanmarese and Indonesian seafarers to come on board in domestic vessel. In regarding to the Korean law, there are no direct relationship between boarding foreign crew in domestic vessel. However the baxic concept of cabotage will be spoiled by boarding foreign crew under the regulation of cabotage, so special treatment should be needed to cover the problems in coastal shipping arose form them. To minimize the problems derived from foreign crew, following actions are recommended; first, management skills of foreign crew are needed to overcome differences of communication and culture; second foreign crew supporting center should be established to counsel their difficulties; third, high level of manning companies should be promoted; forth, stabilized crew supply should be guaranteed by improving employment condition; finally, memorandum of understanding should be concluded between two countries to prevent seceders.