기존에는 생산되는 키틴과 키토산의 대부분이 게, 새우등 갑각류 껍질에서 유래하였다. 하지만 어업에 의존하 는 기존 갑각류 비해 친환경적이며 품질 유지에 이점을 가지는 곤충으로부터 유래한 키틴이 최근 주목 받기 시작 하며 연구가 활발해지고 있다. 이에 키토산이 남조류의 응집을 통해 녹조 제거 효과를 가지며 기존에 녹조를 억제하기 위해 널리 사용되던 살조제들이 독성을 띠어 환경에 악영향을 미치는 문제를 해결할 수 있다는 연구를 참고하여 매미 탈피각으로부터 추출한 키토산을 녹조 방제에 활용해 보고자 하였다. 매미 탈피각으로부터 키토 산을 추출하고 대표적인 녹조 원인종인 Microcystis aeruginosa 배양 후 추출한 키토산을 처리하여 녹조의 응집 효과를 관찰하였다. 본 연구에서 새로운 키토산 추출 원으로서 매미 탈피각의 가능성을 제시하였으며 이를 녹조 방제에 활용함으로써 버려지는 자원인 매미 탈피각의 활용 방안을 제시하였다.

This paper aims to expand our understanding on the success factors of small businesses, which comprise of more than 90 percent of all businesses in U.S. in 2016. One of the most critical issues behind small business success is the competition, which becomes increasingly intense. Not only small businesses fiercely compete with larger competitors (e.g. Emergence of mega-retailers such as Wal-Mart has intensified the competition in the grocery industry, and, as a result, many mom and pop stores have gone out of business.), but also the competition against each other (i.e. competition between small businesses) becomes increasingly aggressive. Yet, the current literature in marketing have less investigated the issue of competition between small businesses, while issues on competition between small and large businesses have been somewhat explored. Another phenomenon in small business that has not received much attention is the competition between generalist and specialist firms. This phenomenon of specialist versus generalist competition is in fact frequently observed in many industries. Therefore, we study competition between small businesses, focusing on the competition between generalist and specialist small businesses. We examine how competitive intensity, as well as market environmental factors, affect the performance of small businesses. Specifically, we decompose the competitive intensity into two types, one between generalists and the other between specialists, in order to identify the differential effects of competition between generalist and specialist, and examine their impacts on the generalist and specialist performance. Given the research questions above, we develop the following hypotheses based on the past research in marketing. First, we expect competition has a positive effect on generalist performance, while we expect the opposite effect on specialist performance. We also expect that the effect of competition becomes weaker, as the competition becomes more intense. That is, the positive (negative) impact of competition on generalist (specialist) performance becomes less significant as there are more competitors in the market. We further expect that competition between the same type of businesses (e.g. between generalists) has a positive effect on their performance, while competition between the difference types (e.g. between generalist and specialist) has a negative effect on their performance. Moreover, we expect that market environmental factors have differential effects on the performance of generalist and specialist. To test the aforementioned hypotheses on the small business competition between generalist and specialist, we collected data from the health care industry on private physician practices (offices) in Korea. Out data contain, for each practice, monthly sales, number of doctors, number of nurses, type of practice, number of beds and zip code it is located in. We also have data on average consumer spending, average medical spending, percentage of patients over sixty years old for each zip code. Moreover, we have data on competition between the same type of offices (e.g. between generalists and between specialists) and competition between different types (e.g. between generalist and specialist). Note that our data collected from the Korean health care industry fit our research questions well. First, the majority of medical service providers in Korea are small private practices with an average number of two doctors, and the share of generalist and specialist practices are about half-and-half. Second, unlike the U.S. health care industry, generalist physicians in Korea usually practice a number of different fields, while specialist physicians focus on their own specialties. Third, patients in Korea do not usually distinguish between generalist and specialist offices, and they do not usually have a primary care physician. As a result, patients can easily switch between physicians, and in fact the switching is highly likely, as all medical information is centralized by government. Our main findings are as follows. First, we find that competition has a positive effect on generalist performance, while it has a negative effect on specialist performance. Specifically, we find that generalist benefits from competition with both generalist and specialist, while specialist suffers from the competition with both specialist and generalist. As competition becomes intense, meaning the number of physician offices increases, it would attract more patients to visit the area where physician offices are clustered (clustering effect), while it becomes easier for patients to switch from one to the other nearby offices. In particular, as generalist usually treats multiple fields (specialties), generalist tends to benefit from the patients who switch from specialist. In other words, generalists benefit from competition, as they free ride on clustering of physicians including specialists, while specialists would suffer from competition. Second, our findings show that as the competition becomes more intense, its effect on business performance becomes weaker. That is, a high level of competition weakens the benefits and damages imposed on the performance of generalist and specialist, respectively. When there are more physician offices to switch, the effect of free riding becomes weaker, as patients have more options to choose from. Thus, the benefit of generalist from free riding becomes weaker, as well as the negative effect on specialist performance. Moreover, our findings suggest that market environmental factors do influence the business performance. Specifically, the performance of both generalist and specialist improves as the number of doctors increases. However, an increase in the number of nurses has a different effect on generalist and specialist. Employing a larger group of nurses has a negative effect on generalist because it might cause the operation of the office to be less efficient. However, since specialist’s practice usually involves a more technical and sophisticated processes, a larger group of nurses could make the office more efficient having a positive impact on the sales performance. Similarly, we find the effects of other environmental factors have differential impacts on the performance of specialist versus generalist.

The two related species in the tribe Archipini, Adoxophyes paraorana and Pandemis heparana (Lepidoptera: Tortricidae), are insect pests of fruit trees in Korea. We investigated differences in pheromone system and seasonal flight of these two species. GC-MS analyses of pheromone gland extracts revealed that females of both species produce blends of Z11-14:OAc, Z9-14:OAc, and Z11-14:OH in similar ratios. The average ratio of three components in extracts was estimated to be 3:100:0.3 for A. paraorana and 3:100:2 for P. heparana. Field tests showed that Z11-14:OAc and Z9-14:OAc were essential for attraction of A. paraorana males and the presence of Z11-14:OH in primary binary blend did not induce any synergistic or inhibitory effect. For the attraction of P. heparana males, however, all three components, Z11-14:OAc, Z9-14:OAc and Z11-14:OH, were indispensable. These results suggest that male A. paraorana do not discriminate between conspecific females and those of P. heparana in the field. Comparison of the flight phenologies in apple and pear orchards showed that the two species are sympatric and overlap in flight periods. This finding eliminates pheromone specificity and seasonal separation as premating reproductive isolation mechanism between A. paraorana and P. heparana.

As an aquaculture effluent is recognized as a source of water pollution, many methods are being researched to solve this problem. It has been reported that the aquaculture effluent contains many organic compounds containing nitrogen, phosphorus, potassium, and calcium. The purpose of this study was to investigate the possibility of using the effluent from bio-floc technology (BFT) inland aquaculture for fertilizing blueberry ‘Duke’ to promote the growth. The experiment was conducted in a commercial blueberry farm in Jinju, Gyeongsangnam-do, where blueberries are actually cultivated in order to find out the effects of fertilizers in situ. The experiment was carried out with five treatments: control with only irrigation, conventional nutrient solution fertigation, and the fertigation with three concentrations (×1, ×0.5, or ×0.25) of effluent from BFT (Bio-Floc Technology) inland aquaculture. The treatment period was from the beginning of April, when a new leaf of blueberry began to develop, to the middle of June, when the blueberry was harvested, for a total of 10 weeks. As a result of the experiment, the treatments with effluent from BFT inland aquaculture showed better growth qualities than those of control and conventional cultivation. However, there was no statistically significant difference among all treatments regarding the total fruit production. Based on these results, it was concluded that the effluent from BFT inland aquaculture can be used for the cultivation of blueberry because it is equivalent to conventional cultivation method. This study provided a new viewpoint of recycling the effluent from BFT for agricultural purpose to reduce water pollution problems due to aquaculture wastewater.

As the interest in urban agriculture and people’s demand for eco-friendly food grow, the number of urban gardeners who directly grow and harvest will increase. The aim of this study was to compare the effect of conventional fertilizer with the effluent water from the biofloc technology inland aquaculture in the concept of resource circulation as a substitute for fertilizer used in urban agriculture. In order to verify the effect of fertilizer on the cultivation of cherry tomato, tomato seedlings were transplanted on the horticultural soil without nutrients and treated for 8 weeks. Experimental treatment was carried out in five treatments: control, hyponex solution (HS), slow-released fertilizer (SF), effluent water daily treatment (DE), and effluent water treatment once a week (WE). The growth characteristics of the cherry tomatoes showed significant differences among the treatments except for root length. In the case of plant length was shown HS=WE›DE=SF›control, and stem diameter was shown DE=SF ›WE=HS›control. It was found that HS and WE were not significantly different in shoot length and diameter, and DE and SF showed no difference. In the case of number of leaves, HS, DE, and WE showed a significantly higher level than SF and control. In other growth characteristics, DE and SF showed higher growth. As for the growth of cherry tomato fruit, the sugar content did not show any significant difference among the treatments except control. Weight per fruit and yield were significantly higher in HS and WE than DE and SF. Based on these results, it is considered that the use of effluent water is comparable to the use of urban agricultural fertilizer as compared with chemical fertilizers in cultivating crops.