검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 55

        41.
        2014.07 구독 인증기관 무료, 개인회원 유료
        Although several causal studies investigate the relationships between customer equity (CE) and firm performance, there has been some debate about whether their positive relationship is valid over long time horizons and across firm/industry environments. In this paper, we investigate the dynamic effect of CE on firm performance. Using individual-level purchase data for an online retailer, we find a weak relationship between CE and firm profitability, which is not consistent with previous assumptions and beliefs. Additional analysis to resolve this gap shows that in the early stage when a firm’s growth rate is relatively high the firm is required to manage many newly enrolled customers. This means that newly acquired customer equity (NCE) has a larger effect than retained customer equity (RCE) on firm profitability in the early stage. In contrast, in the mature stage when a firm’s growth rate is stable and low the firm should retain its customers. This means that RCE has a larger effect than NCE on firm profitability in the mature stage. Thus, marketing managers need to leverage the drivers of acquisition and retention to continue to grow overall CE and firm performance.
        7,800원
        42.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Standing crop distribution of aquatic plants in the West Nakdong River and riparian wetlands inthe Nakdong River were surveyed in May, July and September, 2010. Total 25 aquatic macrophyte species(submerged: 9, leaf-floating: 3, free-floating: 5, emergent: 8) were observed during the survey periods.Distribution area of aquatic plants and proportion of submerged communities were highest in Garakchi-deung(212,032m2, 72.7%). The distribution area of aquatic plants was highest in Phragmites australiscommunity(421,584m2), followed by Hydrilla verticillata-Vallisneria natanscommunity(181,511m2), Potamogetonwrightii-Vallisneria natanscommunity(61,604m2), and Hydrocharis dubiacommunity(49,709m2). Garakchi-deung(212,032kg) also had the highest aquatic plant production, followed by Suanchi-deung(15,546kg),Daedong(5,813kg), Dunchi-do(3,963kg), Maekdo(1,463kg), Yeommak(571kg), Jungsa-do(530kg), andShinan(300kg). Average standing crop of the study area were 147.8±20.8g DW∙m-2in 1988, 96.1±20.0gDW∙m-2in 2000, and 172.6±76.1g DW∙m-2in 2010. For a sustainable management of river habitat andfood source, aquatic plant should concurrently be surveyed with river environmental variables(i.e. sediment,nutrient, flow).
        4,000원
        43.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        일반인들의 생물다양성 인식정도를 지방자치단체 및 기초자치단체의 자연상징물 (새, 꽃, 나무)의 종수로 파악 한 결과 전체 종다양성은 40목 59과 90속 114종이 자연 상징물로 지정되어 있었다. 상징새 38종, 꽃 40종, 나무 36종이 지정되어 있었으며, 새는 까치, 꽃은 철쭉, 나무는 은행나무가 높은 빈도로 지정되었다. 연안에 위치한 지역 에서는 갈매기과에 속한 새와 동백꽃, 소나무과에 속한 종을, 내륙에서는 까치나 비둘기와 같은 텃새류와 진달래 과에 속한 식물종 등 주변에서 흔히 관찰되는 종들이 자 연상징물로 지정되어 있었다. 자연상징물로 지정된 종들 은 크기가 크거나 화려하며 대중적으로 인식정도 높은 종을 선정하였기 때문에 지역간 중복지정된 종들이 많았 다. 대중들이 관심을 갖는 생물종들에 대한 정보가 축적 되면 깃대종 또는 상징종을 지정기준을 설정하고 서식처 보전에 상징종을 이용하는 방안을 수립하는 데도 도움이 될 것으로 보인다.
        4,000원
        44.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        습지의 생태-사회적 가치는 인간사회에 혜택을 준다. 많은 나라들이 습지를 보전하고 보호하기 위해 노력하고 있다. 하지만 많은 습지들은 자연적 교란과 함께 인위적 교란으로 인해 소실되거나 구획화되었다. 구획화된 습지 는 경관생태학적 연구의 주 대상이 되는데 이는 습지를 효율적으로 관리하고 보전하는 데 매우 중요하다. 본 연구 는 행정구역상 경상남도 습지의 공간-사회적 분포양상을 파악하기 위해서 습지의 분포와 크기, 습지 간의 거리, 습 지의 경관학적 형태, 토지이용현황, 공시지가 등을 연구하 였다. 경상남도 내에는 146개(3,598.85 ha)의 습지가 분 포해 있고 하천습지가 76개(1,955.60 ha), 범람습지가 49 개(1,282.28 ha), 산지습지가 21개(1,282.28 ha)이었다. 대 부분의 습지들이 크기가 작고(⁄2 ha) 농경지에 둘러 쌓 여 있었다. 많은 습지들이 구획화되어 있고 훼손상태가 심각하지만 하천습지와 농업용 수로를 이용하여 연결할 수 있는 것으로 보인다. 습지의 연결성 확대를 통한 습지 서식처의 확장은 습지에 의존하여 서식하는 생물들의 보 전에 매우 유의할 것으로 생각된다. 많은 습지들이 현재 농업용수확보를 위한 유지로 이용되고 있고 국유지의 비 율이 높아 추후 습지의 훼손과 소실은 국가단위의 대규 모 계획공사로 인할 가능성이 높으므로 생태적으로 민감 한 행정과 법률의 개발이 습지의 보전과 관리를 위해 중 요하다.
        4,000원
        45.
        2010.05 구독 인증기관·개인회원 무료
        Previous studies indicated that Matsumuraeses phaseoli and M. falcana (Lepidoptera: Tortricidae) are separate species since a few differences were observed in genitalia morphology and female sex pheromone composition. A clear difference was detected in the DNA sequences of cytochrome oxidase I of the two species separately collected in different plants and regions. A hybridization test also showed that a post-zygotic reproductive isolation occurred between the species. In field monitoring, however, both species have been caught simultaneously and together in the separate sex pheromone traps installed for the two species around neighboring soybean and red bean fields. Molecular marker-assisted identification with several adults sampled from the trapped insects showed that only ca. 40% of M. phaseoli adults identified as the species by genitalia morphology was the M. phaseoli, while ca. 97% of M. falcana adults identified as the species was the M. falcana. The result indicated that the observation of genitalia did not make a decisive criterion for classification of the insects. Conclusively, it suggested that the sex pheromones of the two species should be studied more precisely although there is a possibility that the two species are hybridized in fields as in laboratory, and speciation is under process.
        46.
        2010.03 구독 인증기관 무료, 개인회원 유료
        Iron catalyzes the production of free radicals, which can be related to a variety of pathological events, such as cancer and aging. The effect of dietary iron was investigated on formation of colonic aberrant crypt foci (ACF) induced by azoxymethane in male F344 rats. Animals were fed three different diets, including iron-deficient (3 ppm Fe), iron-normal (35 ppm Fe), and iron-overloaded (350 ppm Fe) diets for eight weeks. During the first and second weeks of the experiment, animals received two subcutaneous injections of azoxymethane (AOM, 15 mg/kg body weight) to induce ACF. After staining with methylene blue, the total numbers of ACF and aberrant crypts (AC) were counted on the colonic mucosa. Analysis of blood and serum was performed using a blood cell differential counter and an automatic serum analyzer. Iron-deficient diets induced a significant decrease in red blood cell counts and the values of hemoglobin concentration, hematocrit, mean corpuscular hemoglobin, and mean corpuscular volume, while an iron-overloaded diet did not affect these values. The iron-overloaded diet induced an increase in deposits of iron in the liver of rats, as determined by the ICP method and Perl’s staining. The numbers of ACF per colon showed a slight increase in iron-overloaded or iron-deficient rats, without statistical significance, compared to iron-normal rats. The number of total AC per colon in iron-overloaded rats was significantly higher than that in iron-normal rats (p<0.05). The number of large ACF (≥ 4 AC per ACF) in iron-overloaded rats was also significantly higher than that in iron-normal rats (p<0.05). These results suggest that dietary iron intake may play an important role in colon carcinogenesis in humans and animals.
        4,200원
        47.
        2009.03 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate effect of herbal extracts mixtures on hair growth in an alopecia model of C57BL/6 mice. There were 4 experimental groups including distilled water (DW, negative control), 25% ethanol(EtOH, vehicle control) and two herbal extract mixtures (HE-1 and HE-2). HE-1 included Polygonum and Brassica campestris extracts and HE-2 included Mulberry root and Gardenia extracts. The 6 weeks-old C57BL/6 male mice were shaved with an electric clipper and the test compounds were topically treated with 0.2 ml per mouse daily for 3 weeks. The hair re-growth was photographically determined at days 0, 4, 7, 10, 14, 17, and 21. The number of mast cells which is an important modulator of hair growth was counted in 1 cm of dorsal skin section of mice. There were no clinical signs in all experimental groups. As the results of photometric analysis, the topical application of the herbal extracts (HE-1 & 2) for 2 weeks to dorsal skin accelerated hair re-growth remarkably faster than that of DW group (p<0.05). Activity of alkaline phosphatase (ALP) was significantly increased in EtOH group compared to DW group (p<0.05). Both herbal extract mixtures also increased the ALP activity, but it was not significantly different from DW. Treatment of mice with HE-2 significantly increased mast cell population compared to EtOH. Taken together, these results suggest that herbal extract mixtures used in this study may have hair-growth promoting activities and can be useful for treatment for male pattern baldness or alopecia in humans.
        4,000원
        48.
        2015.07 서비스 종료(열람 제한)
        Ramie (Boehmeria nivea L.) is a hardy perennial herbaceous plant of the Urticaceae family and has been grown as a fiber crop in several countries including Korea for many centuries. Ramie leaves also have been traditionally used as a major ingredient of a type of rice cake called ‘Song-pyun’ in the Southwest area of Korea, especially Yeong-Gwang province. Despite its economic importance, the molecular genetics of ramie have not been studied in detail yet. Genetic resources of ramie were widely collected from domestic local sites by Bioenergy Crop Research Center (RDA) and Yeong-Gwang Agricultural Technology Center. For the systematic and efficient management of the genetic resources, we developed SSR (simple sequence repeat) markers of ramie. To do this, we generated microsatellite-enriched genomic DNA libraries using magnetic bead hybridization selection method. 247 non-redundant contigs containing SSR motif were generated using nucleotide sequences of 376 clones from the libraries. Primer sets were designed from the flanking sequences of the repeat motif. Finally, we selected 10 SSR markers, possibly showing polymorphism among the genetic resources. Results on the genotype analysis of the ramie genetic resources using the SSR markers will be presented.
        49.
        2014.07 서비스 종료(열람 제한)
        Genome sequencing researches for considerable numbers of crops and wild plants are being developed. Cytogenetic researches according to chromosome number and size are essential to confirm and comprehend ploidy level and genome size before genome sequencing project is actually conducted. Cytogenetic researches on six food crop plants were carried out by DAPI staining and fluorescence in situ hybridization (FISH) method. Fagopyrum esculentum Moench showed 2n=2x=16, each chromosome length of 1.42㎛ to 1.77㎛, total chromosome length of 13.31㎛, and karyotypic formula of 2n=8m; Phaseolus angularis W.F. Wight, 2n=2x=22, 2.01㎛ to 3.84㎛, total 28.03㎛, 2n=9m+2sm, Perilla frutescens var. japonica Hara, 2n=2x=40, 1.73㎛ to 2.76㎛, total 44.36㎛, 2n=5m+13sm+2st. Chromosome sizes of the other three species such as, Panicum miliaceum L., 2n=2x=36, total chromosome length of 30.83㎛, Sesamum indicum L., 2n=2x=26, 27.39㎛, lpomoea batatas L., 2n=2x=30, total 33.51㎛ were too small for each chromosome type to be identified and analyzed. The result of FISH analysis using 5S and 45S rDNA probe showed species-specific chromosome locations in the genome. These preliminary analyses were carried out to decide which food crop to prioritize for genome sequencing. This work was supported by the “Cooperative Research Program for Agriculture Science & Technology Development (No.PJ009837), Rural Development Administration, Republic of Korea.
        50.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        The objective of this study was to analyze correlation between phenological characteristics of Salix spp. and meteorological factors in the Upo wetlands. Phenology of Salix subfragilis Andersson and Salix chaenomeloides Kimura was monitored from 2007 to 2012. Meteorological variables were monitored by Korea Meteorological Administration (Hap-chon). Average date of flowering, fruiting, seed dispersion was 86, 113, 136 days for S. subfragilis and 112, 140, 164 days for S. chaenomeloides as Julian days. Flowering of S. subfragilis and S. chaenomeloides were correlated with daily mean air temp. in March (r=-0.92, r=-0.85, p<0.05). Fruiting of S. subfragilis was correlated with total precipitation between Jan and March of previous year (r=-0.90, p<0.01), however, the fruiting of S. chaenomeloides was highly correlated with max. temp. in Jan of previous year (r=0.99, p<0.01). Seed dispersion of both species is correlated with min. temp. in Feb. Phenology monitoring will contribute to understanding Salix spp. response against climate change.
        51.
        2012.06 KCI 등재 서비스 종료(열람 제한)
        Cryopreservation has been known as an efficient method for long-term preservation of clonally propagated plants, and several cryopreservation methods have been developed. Among them, a droplet-vitrification method for potato using axillary shoot tips in vitro has been established previously. In this study, we have optimized the procedure in which explants were submitted to a step-wise pre-culture in liquid sucrose-enriched medium (0.3 and 0.7 M for 7 and 17 h, respectively). The pre-cultured explants were dehydrated with PVS3 (w/v, 50% glycerol + 50% sucrose) for 90 min or modified PVS2 vitrification solution (w/v, 37.5% glycerol + 15% DMSO + 15.0% ethylene glycol + 22.5% sucrose) for 30 min. This two dehydration solutions produced post-cryopreservation regeneration percentages of 57.2% and 80.9%, respectively. We also compared a new post-culture medium (0.1 mg L ・ -1 GA3, 0.1 mg L ・ -1 kinetin) with the conventional one (0.15 mg L ・ -1 IAA, 0.2 mg L ・ -1 zeatin, 0.05 mg L ・ -1 GA3); the shooting initiation rates were 80.9% and 43.5%, respectively. The results suggest that the modified droplet-vitrification protocol described in this study is more effective, easier to implement, and more economical than the droplet-vitrification protocols currently used for potato.
        52.
        2007.12 KCI 등재 서비스 종료(열람 제한)
        "Chuyoung" as a new double cropping potato variety was bred in 2005 for table use through a cross between "Dejima" with short tuber dormancy and HRB-31 which is a tetraploid derived from an interspecific cross between "Russet Burbank" and Solanum phureja line. It was evaluated for short dormancy, growth and tuber characteristics every twice a year from 1997 to 2001. Regional yield trials were performed from 2002 to 2004 at three locations, Jeju, Namhae and Gangneung of Korea, respectively. Its tuber shape is oblong with yellow skin and flesh colors. Its dormant periods is 60~70days. It showed less incidence of physiological disorders such as cracking or knobs on tubers, and higher resistance to common scab by Streptomyces scabies compared to "Dejima". It has tall plant height and erect growth type with green-broad leaflets and white large inflorescence. Its average yields are 29.5 and 22.6 ton/ha at 90 days after planting in spring and autumn cropping, respectively. It also showed higher marketable yield due to the lower incidence of common scab and physiological disorders compared to "Dejima".
        1 2 3