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        검색결과 13

        2.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to improve growth performance of Hanwoo heifer and to produce high quality of meat with dietary means during growing and early fattening period. Particularly, additional energy diet to relieve estrus stress was main purpose in this study. The results of in vitro rumen fermentation indicated that there was no negative effect by additional energy diet as treatments. In the feeding trial, twenty Hanwoo heifers(average 10 months age) were allocated and distributed into two treatments in randomized block design based on body weight. There were three growth stages such as growing, early fattening and late fattening periods in this feeding program, respectively. In growing stage, there were two treatments consisting of only total mixed ration(TMR) as a control and TMR with additional energy treatment. The experimental diets were fed twice a day, and water and mineral were freely accessed. In additional energy treatment, 500 g of concentrate diet was fed daily to relieve estrus stress due to obese with high energy intake. Not outstandingly differences were found across the treatments during entiretrial period. While, unexpectedly greater feed conversion ratio in treatment compared to the control was found during late fattening period. It seems that the blood cortisol decreased with addition energy supplementation compared with the control during trail period. Carcass characteristics including carcass weight, back fat thickness, marbling score, meat color, fat color, maturity and texture were not significantly different each other. Rib-eye area, however, was greater in the control compared to the treatment(p<0.05). In addition, it appears that yield index was tended to be greater in the control. In conclusion, it is suggested that additional energy supplementation to Hanwoo heifer could get a potential in improving meat quality and relieving estrus stress.
        4,000원
        3.
        2018.04 구독 인증기관·개인회원 무료
        우리나라는 1996년 WTO/SPS(동식물검역협정)에 따라 검역병해충제도를 정비하였으며, 해외병해충의 위험으로부 터 자국내 생물자원과 자연환경을 보호하기 위하여 다양한 노력을 하고 있다. 현재까지의 수입식물 검역과정에서 검출된 병해충을 분석한 결과 병해충 검출건수는 수입량이 늘어나면서 증가하는 추세이다(00년 6,233건 → 17년 12,749건). 하지만 식물의 수입 유형에 따라 곡류, 사료류 등 비재식용 식물의 경우 병해충 검출률은 07년 이후 감소하고 있으며(07년 9.8% → 17년 3.3%), 묘목류, 종자류 등 재식용 식물의 경우 11년 이후로 지속적으로 증가하고 있어(11년 7.9% → 17년 22.0%) 재식용 식물을 통한 해외 병해충의 유입 위험도가 가증되고 있는 상황이다. 따라서 우리는 검역본부에서 운영하고 있는 자체 전산시스템인 병해충정보시스템(PIS)을 이용하여 2000년 이후 식물검역과 정에서 발견된 병해충 검출동향과 수입 유형에 따른 검출동향을 비교분석하고, 2016년 대비 2017년 병해충 검출동향을 파악하였다.
        4.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ‘Crown Bell’ 품종은 생육이 왕성하고 엽소 및 잎마름병에 강하며 꽃이 큰 백합 신품종을 육성하기 위하여 2008년 충남농업 기술원 태안백합시험장에서 교배한 OT(Oriental hybrid × Trumpet hybrid)계통의 종간교잡종이다. 모본으로는 노란색의 OT계통 ‘Yelloween’ 품종을, 부본으로는 분홍색의 Oriental계통 ‘Carmina’품종을 화주절단수분법에 의해 교배한 후 2009년부터 2011년까지 기내 종자배양 및 증식 육묘하여 2012년 우수계통(OT12-8)을 1차 선발하였다. 2012년부터 2014년도에 걸쳐 ‘Nymph’ 품종을 대조구로 하여 보통재배를 통한 특성검정을 실시하였으며, 2013년 화훼연구소에서 개최한 신품종 평가회에서 기호성이 우수한 개체를 2차 선발하여 ‘Chungnam OT-2’로 명명한 후 농촌진흥청 농작물직무육성 신품종선정위원회 심의를 거쳐 국립종자원에 ‘Crown Bell’로 품종보호 출원하였다. ‘Crown Bell’ 품종의 중부지역 자연 개화는 6월 26일로 ‘Nymph’ 품종보다 약간 빨랐으며, 초장은 136.1cm이고, 반점없는 복색(크림색+적색)의 화색을 가진 상향개화성을 나타내었다. 재배에 있어서는 잎마름병과 진딧물 등의 병충해 방제를 주기적으로 실시하고, 양수분 관리 등 일반적인 재배관리를 통해 고품질 절화 백합 및 구근 생산이 가능하다.
        4,000원
        5.
        2017.07 구독 인증기관·개인회원 무료
        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.
        7.
        2014.09 서비스 종료(열람 제한)
        We investigated the effect of light spectra on circadian rhythm by exogenous prolactin (PRL) by using light emitting diodes (LEDs): red, green, and purple. We injected PRL into live fish or treated cultured brain cells with PRL. We measured changes in the expressions of period 2 (Per2), cryptochrome 1 (Cry1), melatonin receptor 1 (MT1) mRNAs, and MT1 proteins, and in the plasma PRL, serotonin, and melatonin levels. After PRL injection and exposure to green LED light, MT1 expression and plasma melatonin levels were significantly lower, but the expressions of Per2 and Cry1 were significantly higher than others. Plasma serotonin after PRL injection and exposure to red LED light was significantly lower than others. These results indicate that injection of high concentration PRL inhibits melatonin, and inhibited melatonin regulates circadian rhythm via clock genes and serotonin. Thus, exogenous PRL regulates the circadian rhythm and light spectra influence the effect of PRL in goldfish.
        9.
        2011.09 서비스 종료(열람 제한)
        Human embryonic stem cells (hESCs) have the potential for use in regenerative medicine and in the field of basic research. Therefore, effective cryopreservation and storage of hESCs are important for preservation of newly established cell line for various purposes. Despite poor survival and slow recovery after thawing, the conventional slow freezing method is most commonly used for cryopreservation of hESCs due to its simplicity and ease of use for freezing a large number of hESCs appropriate to clinical applications. Here we controlled the clump size (Group Ⅰ; 400~450 ㎛, Group Ⅱ; 800~900 ㎛, and Group Ⅲ; 1500~1700 ㎛) of hESCs at 5 days after plating using a glass pipette during cryopreservation in order to obtain a larger amount of hESCs after thawing. Attachment rates differed significantly (P<0.05) in each of the three groups and the average of attachment rate of GroupⅡ was highest in SNUhES4 and H1. In particular, the attachment rate of Group Ⅱ in SNUhES3 showed a significant improvement with ROCK inhibitor Y-27632. These results indicate that clump size and cell-cell adhesions of GroupⅡ are appropriate for cryopreservation compared to the Group Ⅰ and Group Ⅲ. This method increased cell viability and reduced the recovery time leading to various experiments, and therefore has an advantage for use with hESCs like newly established in particular. We demonstrated that use of this effective cryopreservation method with control of the clump size of hESCs can effectively improve the attachment rate and survival of post-thaw hESCs with and without Y-27632.
        12.
        2007.03 KCI 등재 서비스 종료(열람 제한)
        ‘Gwangan’ is a new six-rowed covered barley cultivar developed by the National Institute of Crop Science (NICS), R.D.A in 2004. This cultivar is developed from a cross between “Mirak” and ‘Milyang59’ in 1995. An F6 selection was made at Milyang in 2001 an
        13.
        1999.09 KCI 등재 서비스 종료(열람 제한)
        In rice-barley cropping systems, efficient utilization of barley straw is essential, both to improve the soil fertility and to conserve the environment. In order to identify the effects of barley straw mulch rates in rice cultivation, a rice cultivar, 'Gancheogbyeo', was directly seeded on a no-tillage field synchronized with barley harvesting with five barley straw mulch rates, i.e., 0, 2.5, 5.0, 7.5 and 10.0 ton h a-1 and agronomic characters of rice and soil nitrogen were determined. The increasing of barley straw mulch rates. Dominant weed species, chestnut, occurred in large amounts in no mulching or lower mulch rates than in higher mulch rates. The content of N H4 + -N in soil applied with high barley straw mulch rates was lower during the month after seeding, and then it was higher at heading date, compared with lower mulch rates or no mulch plot. As the barley straw rate increased, maximum tillering stage was delayed, and plant height was reduced. Although the lodging of rice plants was seldom observed in all plots, the breaking strength of the culm was significantly higher in the mulch rate of 10.0 ton h a-1 . With an increase of barley straw mulch rate, the effective tillering rate and spikelet number m-2 decreased while ripened grain ratio increased. The rice grain yield was slightly decreased with an increase of barley straw mulch rate, although significant differences were not found all barley straw mulch rates. These results suggest that there is no significant yield loss although the total barley straw production, approximately 5.0 ton h a-l in the present study, apply in the paddy for the following rice cultivation by no-tillage direct seeding.ect seeding.