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        검색결과 12

        4.
        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
        5.
        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
        6.
        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.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To breed a new Korean Pleurotus eryngii cultivar with high quality and yield, single crosses between 24×46 and KNR2539 were performed, and a new cultivar, 6×13, was selected based on the days to harvest (14.6 days), quality (7.2), and yield (85.9 g/850 cc bottle). The strain was named Aeryni 5 and cultivated on a large scale at the mushroom farms to compare with Keuneutari 2ho. The yield of Aeryni 5 (82.2 g) was 122.7% of Keuneutari 2ho, and the quality of the new cultivar was 7.7 while reference cultivar was 6.3. The yield and quality of the two cultivars were statistically different. The lightness of the pileus of Aeryni 5 (61.7) was greater than that of Keuneutari 2ho by 3.4 points; thus, the pileus of Aeryni 5 looked brighter. PCR with URP2 was used to discriminate between Aeryni 5 and Kenneutari 2ho.
        4,000원
        8.
        2015.11 구독 인증기관·개인회원 무료
        Pleurotus eryngii, an edible white-rot fungus, is widespread in Eurasia and northern Africa. It has become a major cultivated mushroom in Asia, with a current global production rate of approximately 3 × 10 5 metrictons/yr. To improve the quality or productivity through breeding, a genetic linkage map is an important component. In this study, genetic linkage map of the P. eryngii was constructed using 98 monokaryotic progeny derived from dikaryon of parental KNR2312 strain derived from haploid meiotic spores. The whole genome sequence of P5 monokaryon from P. eryngii KNR2312 strain by Next Generation Sequencing (NGS) strategy was used to design the SSR markers. 484 primers pairs were identified by SSR Locator I and tested polymorphism via PCR. A total of 241 loci were mapped using Joinmap 4.0, comprising 222 SSR markers, 2 mating type factors, and the 13 INDEL markers. The map consisted of 14 linkage groups spanning 1003 cM at an average marker interval of 4.2 cM. The mating loci, A and B were mapped on linkage groups 4 and 11, respectively. The established linkage map and the genetic information based on NGS could be used for QTL mapping of agronomic traits, marker-assisted breeding that may ultimately lead to outstanding phenotypic characteristics. [Supported by a grant from the IPET (213003-04-3-SBY20), MIFAFF, Republic of Korea.]
        9.
        2015.11 구독 인증기관·개인회원 무료
        Differentiation of Pleurotus eryngii is laborious and time-consuming tasks especially in mycelial status. For development of a method for differentiation of P. eryngii cultivars, simple sequence repeats (SSR) from whole genomic DNA sequence analysis was used for genotyping and two multiplex-SSR primer sets were developed. These SSR primer sets were employed to distinguish 12 cultivars and strains. Five polymorphic markers were selected based on the genotypes. PCR with the each primer produced one to four distinct bands ranging in size from 200 to 300 bp. Polymorphism information content (PIC) values of the five markers were in range of 0.6627 to 0.6848 with an average of 0.6775. Unweighted pair-group method with arithmetic mean clustering analysis based on genetic distances using five SSR markers classified 12 cultivars into 2 clusters. Cluster I and II comprised of 4 and 8 cultivars, respectively. Two multiplex sets, Multi-1 (SSR312 and SSR366) and Multi-2 (SSR178 and SSR277) completely discriminated 12 cultivar and strains with 21 allele with a PIC value of 0.9090. These results might be useful to provide an efficient method for the identification of P. eryngii cultivars with separate PCR reactions. (This work was supported by a grant from the Gold Seed Project [Supported by a grant from the IPET (213003-04-3-WTI11), MIFAFF, Republic of Korea.]
        10.
        2008.10 구독 인증기관·개인회원 무료
        In order to select the superior lines of bumblebee queens(Bombus terrestris) in oviposition and colony development which has some characteristics of diapause with adult type, undiapaused bumblebee queens of 3rd generation were surveyed in room condition compared to queen treated with CO2 and artificial hibernation. Oviposition rate and preovipositional days of undiapaused queens was lower in efficacy with 46.7% and shows same trend in preovipositional days with 52.8 days than the other treatment with CO2 anesthesia and artificial hibernation with 60.0%, 86.7%, 26.1 days and 26.6 days respectively. In continuous experiment, we also surveyed ovipositional characteristic and colony development of three types of queens emergenced from undiapaused queens and treated queens with CO2 and artificial hibernation. Although undiapaused queens in 1st generation were more effective in the same condition than treated queens, but the undiapaused queens of 3rd generation emergenced from undiapaused queens of 2nd generation were very low trend in all checkpoints compared with treated queens in same generation. This results was shown that the queens treated with CO2 or artificial hibernation need to be in successive mass rearing continuously in the year round.
        11.
        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
        12.
        2004.03 KCI 등재 서비스 종료(열람 제한)
        A reproducible transformation system via optimized regeneration media for Korean rice cultivars was established using Agrobacterium tumefeciens LBA4404 (pSBM-PPGN; gusA and bar). Although japonica rice genotypes were easier to produce transgenic plants compared to Tongil type cultivars, transformation efficiencies were not always correlated with regeneration efficiencies of non-transgenic callus on the control medium. Regeneration efficiencies of Donganbyeo, Ilmibyeo, and Manchubyeo were over 50% in non-transgenic control, however, transformation efficiencies were significantly low when only sucrose was added to the media as a carbon source. However, the medium, MSRK5SS-Pr (or MSRK5SM-Pr), that contains 5~textrmmgL-1 kinetin, 0.5~textrmmgL-1 NAA, 2 % sucrose (or maltose), 3% sorbitol, and 500~textrmmgL-1 proline, was the most efficient not only for regeneration of non-transgenic callus but also for regeneration of transgenic callus in the presence of L-phosphinotricin (PPT). Average transformation efficiencies of 16 Korean rice cultivars were significantly enhanced by using the optimized medium from 1.5% to 5.8% in independent callus lines and from 2.9% to 19.4% in tromsgenic plants obained. Approximately 98.9% (876 out of 885) transgenic plants obtained on optimized media showed basta resistance. Stable integration, inheritance and expression of gusA and bar genes were continued by GUS assay and PCR and Southern analysis of the bar gene. With Pst1 digestion of genomic DNA of transgenic plants, one to five copies of T-DNA segment were observed; however, 76% (19 out of 25 transgenic plants) has low copy number of T-DNA. The transformants obtained from one callus line showed the same copy numbers with the same fractionized band patterns.