• The Korean Journal of Malacology
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• v.30 no.2
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• pp.107-116
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• 2014

Gonadal development and maturation mechanism were studied on the freshwater marsh clam Corbicula papyracea (Heude), which is the endangered species in Korea. The specimens were collected in the rearing ponds and waterway of NFRDI in Gapyeong-gun, Gyeonggi-do from January to December 2004, and then investigated by condition factor, relative growth, gonadal development phases and gonad histological characters based on 30-50 individuals every month. Comparing with the freshwater marsh clam, C. papyracea is small, light olive brown shell and violet interior. The hermaphrodite individuals of C. papyracea take an internal fertilization and fertilized eggs are stored in the foster-sack in the gills, then the hatched juveniles are released outside after an ovoviviparous process. The average water temperature of inhabit area was in range of $1.8-27.0^{\circ}C$ and usually took great effects on the gonad maturation of C. papyracea. The condition factor ranged from 0.14 to 0.21 throughout the year, which was the lowest during winter season (December-February), and gradually increased to the highest value of 0.21 in May. The ratio of meat weight to total weight was 25.9-38.7%, indicating the similar trend with condition factor. The highest values of condition factor and the ratio of meat weight appeared 1-2 months later than gonadosomatic index reached the peak value, it was probably because that the ovoviviparous eggs would spend a long period before hatching from the foster-sack in the gills. To synthesize the characters of meat weight, condition factor and gonad development by histological study, reproductive cycle of C. papyracea could be divided into five successive stages: multiplicative stage (December to February), growing stage (February to May), mature stage (June to August), spawning stage (August to November), recovery stage (November to December). The smallest shell length of matured C. papyracea was 12.6 mm, and individuals, larger than 16 mm, was formed the nursery in the gills.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1575-1581
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• 2005

This study was conducted to determine the characteristics of IGFBPs in plasma of steers, and to profile the relationship between growth and plasma IGF-1 and IGFBPs with aging in Holstein steers. Four blots of IGFBP at molecular weights of 38-43, 34, 29-32 and 24 kDa bands were detected by western ligand blot assay using $^{125}I-IGF-1$. On the basis of immunoblotting with anti-bovine IGFBP-2 and -3 antiserums, we observed the band for IGFBP-2 at approximately 34 kDa, and the IGFBP-3 band was detected at 38-43 kDa and 34 kDa in adult steers and calves. The IGFBP-3 antiserum used on the blots exhibited significant cross-reactivity with 34 kDa IGFBP-2. Furthermore, the 38-43 kDa IGFBP-3 bands were reduced to a 36 kDa band after deglycosylation, whereas the 34 kDa IGFBP-2 was intact. The plasma IGF-1, IGFBP-3 and other IGFBPs showed stability throughout a whole day. The change in live weight was found to be positively correlated to the plasma IGF-1 concentration (r = 0.6801, n = 64, p<0.05) and plasma IGFBP-3 (r = 0.6321, n = 64, p<0.05), while inversely correlated to plasma IGFBP-2 (r = -0.2919, n = 64, p<0.05). Furthermore, plasma IGF-1 was positively correlated to plasma IGFBP-3 (r = 0.6191, p<0.001), but was not correlated to plasma IGFBP-2. The portion of IGFBP-2 for total IGFBPs in calves was higher than in adult steers (p<0.05) and was decreased with growth, whereas that of IGFBP-3 was increased with increased live weight (p<0.05). The ratio IGFBP-3 for IGFBP-2 (BP-3/BP-2) was increased with growing of liveweight. Therefore, the changes in plasma IGF-1 level with increased liveweight may be related to the changes in plasma IGFBP-3 level and IGFBP-2 may give an important role in anabolic action of IGF-1 with the growth of body during calfhood in Holstein steers.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.349-355
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• 2010

This experiment was conducted to establish the optimum nitrogen application level for oriental melon at Seong-ju Fruit Vegetable Experiment Station with a fertigation system. Four different levels of nitrogen fertigation were applied to oriental melon and growth of the plant was analyzed. Plant samples were collected 8 times and were analyzed by the standard methods. The first fertigation was applied at 10 days after transplanting for the oriental melon based on the growth rates of the plants. For oriental melon, 10 day interval fertigation and 8 time split application of fertilizer could be recommended. The amounts of N, P, and K fertilizer recommended by soil testing was 249-408-315 (kg $ha^{-1}$). Treatment levels were 0, 0.5, 1.0, and 1.5 times of soil testing nitrogen with P and K level fixed. The total nitrogen (T-N) content in dried leaf showed a tendency to increase until 30 days after transplanting, then decreased. T-N content increased with increasing nitrogen fertigation rates. T-N content in dried fruit decreased slightly during the whole growing season. Fresh weight and nitrogen uptake were increased with increasing nitrogen fertigation rates. Total yield and marketable yield, 44,550 kg $ha^{-1}$ and 42,880 kg $ha^{-1}$, were maximized at 0.5 times of soil test nitrogen. Ratio of marketable fruit, 95%, was the highest at 0.5 times of soil test nitrogen. The optimum level of nitrogen for fertigation system was 0.5 times soil test nitrogen judging from total yield, commodity yield and commodity fruit.

• Korean Journal of Environmental Biology
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• v.33 no.4
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• pp.419-424
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• 2015

In order to determine the ovarian cycle of Asian Toad, Bufo gargarizans, the developmental stage based on the gonadosomatic index (GSI), size of follicle oocytes in ovary and vitellogenesis for adult females were investigated all around the year. The weight of ovary and GSI were the lowest from April, and all follicle oocytes exist in the pre-vitellogenic form, indicating that the vitellogenesis was suspended. The follicle oocytes in early-vitellogenic stage appeared in ovary during may when the weight of ovary and GSI start to increased, and the follicle oocytes in mid-vitellogenic and pre-vitellogenic stages existed during June and the weight of ovary and GSI also increased. This indicates that vitellogenesis has been carried out actively during this period. The follicle oocytes in mid-vitellogenic stage and late-vitellogenic stage when the vitellogenesis was also completed existed on September. Post-vitellogenic follicle oocytes after vitellogenesis started to appear from October and rapidly increased from December in hibernation. The full grown follicle oocytes existed during February, indicating the ovarian cycle that all follicle oocytes in ovary are developed separately, not synchronized, during the growing period of follicle oocytes and the post-vitellogenic follicle oocytes are maintained the ovulation period.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.110-122
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• 2014

Korea's film industry has been growing over the last 10 years, and there has been much attention to the antecedents of film box office sales both academic and business communities. So far, previous research which explained success factors of film or movie mainly focused on 3 stages, production, distribution and screening. However, these 3 steps are heavily vertically integrated in Korea's firm industry unlike United States. Almost 130% of movie theaters are multiplex chain and operated by film production companies such as CJ and Lotte Entertainment In this situation, film sales are likely to he affected by movie theaters own facilities or location factors rather than movie contents. Based. on resource-based view and S-C-P paradigm, the authors examined "whether movie theater's facilities factors and trade area factors such as accessibility, competitive situation, and population have effect to movie theater's sales revenues. The results showed that the average occupancy of theater is the most important factor to movie theaters sales in both large and small cities. In large cities, movie theater's facilities factors which included vibration seat special sound system, premium movie theater, VIP lounge are relatively important than trade area factors. In contrast, in small cities, location factors and accessibility are the most important factors to movie theaters sales. We discuss the managerial and theoretical implication for the results and the specific limitations are suggested at the end of the paper.

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.287-292
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• 2014

In order to determine the ovarian cycle of Korean brown frog, Rana coreana, the developmental stage based on the gonadosomatic index (GSI), size of follicle oocytes in ovary and vitellogenesis for adult females were investigated all around the year. The weight of ovary and GSI were the lowest from March to May, and all follicle oocytes existed in the pre-vitellogenic form, indicating that the vitellogenesis was suspended. The follicle oocytes in early-vitellogenic stage appeared in ovary during June when the weight of ovary and GSI started to increase, and the follicle oocytes in mid-vitellogenic and pre-vitellogenic stages existed during August and the weight of ovary and GSI also increased. This indicates that vitellogenesis has been carried out actively during this period. The follicle oocytes in mid-vitellogenic stage and late-vitellogenic stage when the vitellogenesis was also completed existed between September and November. Post-vitellogenic follicle oocytes after vitellogenesis started to appear from December in hibernation, and the full grown follicle oocytes existed during February, indicating the ovarian cycle that all follicle oocytes in ovary are developed separately, not synchronized, during the growing period of follicle oocytes and the post-vitellogenic follicle oocytes are maintained the ovulation period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.615-627
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• 2012

The market penetration of the smart phones has brought significant changes to the related industries. As the mobile phone market as well as the smart phone application market are growing rapidly, competition among small-size application developers has become severe. However, due to the severe competition and expensive market entry costs, the developers argue that it is necessary to develope the applications from the perspective of the users. However, studies on application development from the users' perspectives are still in the early stages and they have not provided various approaches. Therefore, based on the Open Coding method of Ground Theory, this study collected data on applications review from related communities and blogs of Korean web portal sites, and identified indices which users consider important when they use the applications. In addition, we conduct a comparative analysis between those indices by calculating their frequency of exposure. As a result, a total of 30 sub-categories of indicators such as amusement, controllability, versatility and ease of use appeared to be predominant to users and those lower categories were grouped into five categories; sensibility, design, technology, price, and social skills. The results of this study suggest to the application developers the guidelines of user oriented design and development. It can be used to develop the evaluation tool for application usability.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.274-284
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• 2014

Crops and varieties are mostly affected by temperature, the amount of precipitation, and duration of sunshine. This study aims to identify the weather factors that directly influence to apple yield among the series of daily measured weather variables during growing seasons. In order to identify them, 1) a priori natural scientific knowledge with respect to the growth stage of apples and 2) pure statistical approaches to minimize bias due to the subject selection of variables are considered. Each result estimated by the Panel regression using fixed/random effect models is evaluated through suitability (i.e., Akaike information criterion and Bayesian information criterion) and predictability (i.e., mean absolute error, root mean square error, mean absolute percentage). The Panel data of apple yield and weather factors are collected from fifteen major producing areas of apples from 2006 to 2013 in Korea for the case study. The result shows that variable selection using factor analysis, which is one of the statistical approaches applied in the analysis, increases predictability and suitability most. It may imply that all the weather factors are important to predict apple yield if statistical problems, such as multicollinearity and lower degree of freedom due to too many explanatory variables used in the regression, can be controlled effectively. This may be because whole growth stages, such as germination, florescence, fruit setting, fatting, ripening, coloring, and harvesting, are affected by weather.

• Journal of Music and Human Behavior
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• v.15 no.1
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• pp.1-23
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• 2018

Recently, there has been a growing focus on the concerns pre-service teachers have as they move through different stages of their teacher preparation programs. Accordingly, the purpose of this study was to investigate pre-service secondary music teachers' concerns about music teaching and learning. The specific research questions were as follows: (a) What concerns are most common among participants? (b) What are differences in the concerns of pre-service secondary music teachers based on their stage of teacher preparation? (c) What are differences in the concerns of pre-service secondary music teachers based on their previous teaching experiences? A survey was distributed to pre-service secondary music teachers in a university in Seoul, and responses from a total of 93 participants were included in the final analysis. Data analysis indicated that pre-service music teachers experienced more concerns related to teaching tasks and student impact than themselves. Also, as participants progressed through their teacher preparation programs, self concerns decreased while task concerns and student impact concerns increased. Pre-service secondary music teachers who had previously taught in a school had fewer concerns than participants with no teaching experience. Suggestions for how teacher preparation programs can address the concerns of pre-service secondary music teachers are offered.

• Korean Journal of Construction Engineering and Management
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• v.2 no.2 s.6
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• pp.68-80
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• 2001

While opportunities for international construction firms have been growing with globalization, the risk of international construction projects is significantly increasing in severity and complexity. However, the traditional risk management approach in the construction industry has maintained a profit focus. In addition, this approach has not considered the overall risk at the corporate level, but rather has focused only on the risk of individuals at the project level. Corporate risk management should be implemented from the initial stages of new project selection. This paper suggests the Multi-criteria Integrated Systematic Analysis as a strategic decision-making tool for international construction contractors. The model integrates the multi-criteria of risk, return, and efficiency to choose the optimal set of new portfolios at the corporate level. This model also introduces the Value at Risk (VaR) concept to the international construction industry to present the total risk at the corporate level. To validate this model, this paper tested an experimental case study using the historical data of a global general contractor.