• Title/Summary/Keyword: Niche

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Diet Partitioning between Co-occurring Amblychaeturichthys hexanema and Amblychaeturichthys sciistius in the Southeastern Korean Waters (동해 남부 연안에 출현하는 도화망둑 (Amblychaeturichthys hexanema)과 수염문절(Amblychaeturichthys sciistius)의 먹이 분할)

  • Huh, Sung-Hoi;Park, Joo Myun;Baeck, Gun Wook
    • Korean Journal of Ichthyology
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    • v.28 no.2
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    • pp.79-86
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    • 2016
  • Stomach contents of Amblychaeturichthys hexanema and A. sciistius (Perciformes: Gobiidae) from southeastern waters off Korea were analyzed to determine dietary habits and the presence of any inter- and intra-specific partitioning of food resources. These two species were bottom-feeding carnivores that consumed mainly benthic crustaceans, and other demersal invertebrates and planktonic organisms were also important in their diets. Non-metric multidimensional scaling (nMDS) ordination and multivariate analyses based on gravimetric contributions of the different prey taxa to stomach contents revealed significant inter-specific dietary differences; i.e. partitioning of food resources between the two species. Size-related changes, however, were not significant for their diets. Differences in the types and range of prey ingested by the two species could often be related to differences in the feeding behaviors. Our results of stomach contents analyses provide clear evidence of niche segregation between co-occurring A. hexanema and A. sciistius in southeastern Korean waters, which would reduce the likelihood of inter-specific competition for food resources.

Stomach Contents of the Stone Flounder, Kareius bicoloratus and Roughscale Flounder, Clidoderma asperrimum in the Coastal Waters off Tongyeong, Korea (통영 주변해역에 서식하는 돌가자미(Kareius bicoloratus)와 줄가자미(Clidoderma asperrimum)의 위내용물 조성)

  • Nam, Ki Mun;Huh, Sung-Hoi;Heo, Yoo Shim;Jeong, Jae Mook;Kim, Hyeon Ji;Baeck, Gun Wook
    • Korean Journal of Ichthyology
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    • v.25 no.3
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    • pp.163-168
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    • 2013
  • Two flatfish species were collected between January 2010 and August 2010 from fishing vessels operating with fishing, gill net and shrimp trawls along the coastal waters off Tongyeong, Korea in order to examine feeding habits. Kareius bicoloratus fed mainly on bivalves and fishes, whereas Clidoderma asperrimum fed mainly on ophiuroids. Our feeding strategy graphical method reveled that K. coloratus and C. asperrimum were specialist predator, with a narrow niche width.

Seasonal Changes of Drosophilidae (Diptera) at the Mt. Soribong in Korea (광릉 소리봉 초파리과의 종구성과 계절적 변동)

  • 김남우
    • The Korean Journal of Ecology
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    • v.22 no.5
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    • pp.311-316
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    • 1999
  • Community organization of the drosophilid flies was investigated with respect to the seasonal variation of the species abundance at the natural forests on Mt. Soribong in Kwang-nung (Kyung-Ki Do, Korea) from May to October 1996. The dominant species were Amiota okadai. Scaptomyza pallida, Hirtodrosophila sexvittata. Drosophila bizonata. D. unispina. and D. brachynephros in the annual collection. A. okadai was found with numerically dominance in April and was found in June with less superiority. S. pallida showed their highest peak in occupational in May and after soon they decreased. There was a remarkable increase in the numbers of H. sexvittata in July. This increase may be coincident with the appearance of fungi which provide a breeding site for this species in the forest. On the other hand, D. biauraria and D. triauraria showed their highest peak in May and after soon they decreased, and in September they made the lower peak again. Four species (D. anguraria. D. brachnephros, D. nigromaculata, D. unispina) of qunaria group were found with dominance in August to September. These results suggest that the predominant species in the forest avoid niche overlap by means of seasonal separation of breeding, which is strongly affected by factors associated with season in the deep wooded forests.

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The Purchasing Behavior of Fashion Goods According to Life Style and Role Model of Preteen Generation (프리틴세대의 라이프스타일과 역할모델에 따른 패션상품 구매행동)

  • Kwon, Yu-Jin;Yoo, Tai-Soon
    • Fashion & Textile Research Journal
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    • v.7 no.3
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    • pp.291-300
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    • 2005
  • The purpose of this study is to investigate, analyze the purchasing behavior of fashion goods according to life style and role model of preteen generation, and provide manager or marketing planner for the reference data so that they can understand preteen generation and make proper strategy efficiently. So called, preteen market focusing on 1014 generation (from ten to fourteen years old) is highlighted. This generation created between the year 1989 to 1993 after Seoul Olympic monopolize parent's love in abundant economic environment and rise to the core of consumption subject. Products aiming at this preteen generation continuously though consumption mind was shrunk greatly due to recession. Only 2~3 years before preteen market was regarded as grey zone which doesn't belong to not only children (between six and nine years old) but also teenagers (between fifteen to eighteen years old). But in recent day their purchasing powers have increased rapidly and age group is divided on details, so that preteen market has become a niche market. Subjects were 333 persons consisting of students in the 4th~6th grade of primary school and the 1st~2nd grade of middle school in Daegu city. Measuring instruments are as follows: 5questions to differentiate preteen generation, 22 questions to measure life style, 17questions (which have six sub-factors such as purchase motive, factor of product selection, utilization of informant, purchase time, purchase place, and purchase method) to measure the purchase behavior of fashion goods measurement, and 16 questions (which have four sub-factors such as parent, entertainer & sports stars, brothers and sisters, friends) to measure model of role. Statistical data were processed by SPSS 10.0 programs. Frequencies, Factor analysis, Cluster analysis, ANOVA, Cross analysis, Multiplex regression analysis, and Duncan's multiple range test were carried out.

Low Carbon.Green Growth Paradigm for Fisheries Sector (수산부문 저탄소.녹색성장 패러다임)

  • Park, Seong-Kwae;Kwon, Suk-Jae
    • Ocean and Polar Research
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    • v.31 no.1
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    • pp.97-110
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    • 2009
  • Two of the most important topics of the 21st century are ensuring harmony between man and his environment and the emerging long-tail economy in which niche markets are becoming increasingly more important. Since the Industrial Revolution in 17th century, human beings have increasingly exploited the world's natural capital, such as the natural environment and its ecosystems. Now the world is facing limits to sustainable economic growth because of limits to this natural capital. Thus, most countries are beginning to adopt a new development paradigm, the so-called"Green Development Paradigm" which pursues environmental conservation in parallel with economic growth. Recently, the Korean government announced an ambitious national policy of Low Carbon & Green Growth for the next six decades. This is an important step that transforms the existing national policy into a new future-oriented one. The fisheries sector in particular has great potential for making a substantial contribution to this national policy initiative. For example, the ocean itself with its sea plants and phytoplankton has an enormous capacity for fixing carbon, and its vast areas of tidal flats have a tremendous potential for cleaning up pollutants from both the sea and the land. Furthermore, the fishing industry has great potential for the development of fuel-saving biodegradable technologies, and a long-tail economy based on digital technologies can do much to promote the production and consumption of green goods and services derived from the oceans and the fisheries. In order for this potential to be realized, the fisheries authority needs to develop a new green-growth strategy that is practical and widely supported by fishing communities and the markets, taking into account the need for greenhouse gas reduction, conservation of the ocean environment and ecosystems, an improved system for seafood safety, the establishment of strengthened MCS (monitoring control surveillance) system, and the development of coastal ecotourism. In addition, fisheries green policies need to be implemented through a well-organized system of government aids, regulations and compensation, and spontaneous (voluntary) orders in fishing communities should be promoted to encourage far more responsible fisheries.

Groping for Growth Strategy of Savings Bank as a result of signing the Korea-U.S. FTA (한.미 FTA 체결에 따른 저축은행의 성장전략 모색)

  • Lee, Hyun-Sik
    • International Commerce and Information Review
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    • v.10 no.3
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    • pp.265-290
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    • 2008
  • Domestic industries are facing the open era as a result of signing the Korea-U.S. FTA with no exception to the financial industry. The FFA between two countries is expected to produce pros and cons for domestic financial industry. Therefore, it is very important to minimize the shock caused by opening our financial market and to adopt the advanced financial tools actively. Signing the Korea-U.S. FTA and enforcing the Integration Law of Capital Market are leading a big crisis to the Savings Banks which have been shrinking under the dramatically changing domestic financial environment since the financial crisis. To cope with financial globalization, Korean Savings Banks are demanded to build up their concrete identity and reposition their status. This is related to shaping the long-term position of domestic financial industry. Therefore, the Savings Banks must take the growth strategy for their survival, and it is an inescapable choice. Several options are available: big scale operation and diversification of business functions, reinforcement of local-focused mediating function of funds, establishment of strategic alliance with other financial firms, reinforcement of risk management system and core competence, nourishment and employment of professional manpower, and active deregulation and policy support. When the Savings Banks are refurbished as an independent local bank performing the central role of local finance, the bright future can be their destiny under the enormously changing global financial environment. Also, two more conditions need to be satisfied: to establish horizontal networks among local banks directed by cooperative Korea Federation of Savings Banks to reverse the weak scale position, and to satisfy their own peculiar niche market with internal countermeasure to face global financial networks.

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A Study on Brand Images of Women's Wear Manufacturers Targeting Middle Aged Women or Older Women (중(中).노년층(老年層) 여성복(女性服) 브랜드이미지 특성(特性)에 관(關)한 연구(硏究))

  • Yang, Seung-Jin
    • Journal of Fashion Business
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    • v.3 no.3
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    • pp.15-26
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    • 1999
  • The purpose of the study was to investigate brand images and fashion leaderships of women's wear manufacturers targeting middle-aged women or older women. Thus, this study was to be an exploratory study to investigate clothing behavior of elderly female consumers and search apprel niche-market for them. The questionnaire consists of questions on brand images, fashion leadership, and merchandise assortment. The subjects were to evaluate their brand images and rated on 5 point Likert-type scales of 29 adjectives. The fashion leadership of these brands was evaluated by the degree of fashion trends adopted on 7 aspects including fashion images, silhouettes, fabrics, colors, design details, accessories, and item-coordinations. For the survey, both interview and the subjects were 66 manufacturers which have national brands or designer brands. Among 44 respondents, 30 respondents were designers and the rest of them were merchandiser or shop managers. The SPSS PC+ package was used to calculate frequency, T-test, and cluster analysis. The results from survey of manufacturers targeting middle-aged women or older women are as follow: 1) The brand imges which they pursue are prestigious, practical, and elegance. 2) There were significant differences in brand images, and national brand manufacturers pursue stronger images in prestigious, chic, intelligent, competency, than designer brand manufacturers. 3) 40 brands were divided into two clusters. 36 brands were included in one cluster, and only 4 brand were belong to the other cluster. In this market, the image of feminity was grouped with the image of prestigious, chic, intelligent, competency. 4) In product planning, the adption level of fashion trends in 7 aspects was generally at medium level, but fashion trends were more adopted in fabric, color, and item-coordination.

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Phylogeographic and Feeding Ecological Effects on the Mustelid Faunal Assemblages in Japan

  • Sato, Jun J.
    • Animal Systematics, Evolution and Diversity
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    • v.29 no.2
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    • pp.99-114
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    • 2013
  • Phylogeographic and feeding ecological studies of seven terrestrial mustelid species (Carnivora, Mustelidae), the Japanese marten Martes melampus, the sable Martes zibellina, the Japanese badger Meles anakuma, the ermine or the stoat Mustela erminea, the Japanese weasel Mustela itatsi, the least weasel Mustela nivalis, and the Siberian weasel Mustela sibirica, representing four biogeographic patterns in the Japanese archipelagos (Hokkaido, Honshu-Shikoku-Kyushu, Tsushima, and Hokkaido-Honshu), were reviewed in order to clarify causes for the faunal assemblage processes of those mustelid species in Japan. Here, three main constraints were extracted as important factors on the mustelid assemblage. First, fundamental evolutionary differences maintained by niche conservatism in each ecologically diversified lineage ("evolutionary constraint") would enable the species to co-occur without any major problem (coexistence among Martes, Meles, and Mustela species). Second, "ecological constraints" would force two closely related species to be allopatric by competitive exclusion (Mu. itatsi and Mu. sibirica) or to be sympatric by resource partitions (Mu. erminea and Mu. nivalis). Third and most importantly, "geological constraints" would allow specific species to be embraced by a particular geographic region, primarily deciding which species co-occurs. The allopatric distribution of two Martes species in Japan would have been established by the strong effect of the geological separation in Tsugaru Strait. Elucidating both phylogeny and ecology of co-existing species in a community assemblage is important to know which species possess distinct lineage and which ecological traits are adapted to local environments, fulfilling the requirement of the field of conservation biology that endemism and adaptation should both be considered. The Japanese archipelagos would, therefore, provide valuable insight into the conservation for small carnivoran species.

NDRG2 Expression Decreases Tumor-Induced Osteoclast Differentiation by Down-regulating ICAM1 in Breast Cancer Cells

  • Kim, Bomi;Nam, Sorim;Lim, Ji Hyun;Lim, Jong-Seok
    • Biomolecules & Therapeutics
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    • v.24 no.1
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    • pp.9-18
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    • 2016
  • Bone matrix is properly maintained by osteoclasts and osteoblasts. In the tumor microenvironment, osteoclasts are increasingly differentiated by the various ligands and cytokines secreted from the metastasized cancer cells at the bone metastasis niche. The activated osteoclasts generate osteolytic lesions. For this reason, studies focusing on the differentiation of osteoclasts are important to reduce bone destruction by tumor metastasis. The N-myc downstream-regulated gene 2 (NDRG2) has been known to contribute to the suppression of tumor growth and metastasis, but the precise role of NDRG2 in osteoclast differentiation induced by cancer cells has not been elucidated. In this study, we demonstrate that NDRG2 expression in breast cancer cells has an inhibitory effect on osteoclast differentiation. RAW 264.7 cells, which are monocytic preosteoclast cells, treated with the conditioned media (CM) of murine breast cancer cells (4T1) expressing NDRG2 are less differentiated into the multinucleated osteoclast-like cells than those treated with the CM of 4T1-WT or 4T1-mock cells. Interestingly, 4T1 cells stably expressing NDRG2 showed a decreased mRNA and protein level of intercellular adhesion molecule 1 (ICAM1), which is known to enhance osteoclast maturation. Osteoclast differentiation was also reduced by ICAM1 knockdown in 4T1 cells. In addition, blocking the interaction between soluble ICAM1 and ICAM1 receptors significantly decreased osteoclastogenesis of RAW 264.7 cells in the tumor environment. Collectively, these results suggest that the reduction of ICAM1 expression by NDRG2 in breast cancer cells decreases osteoclast differentiation, and demonstrate that excessive bone resorption could be inhibited via ICAM1 down-regulation by NDRG2 expression.

Estimation of Habitat Suitability Index of Fish Species in the Gapyeong stream (가평천 어류의 서식처적합도지수 산정)

  • Kong, Dongsoo;Son, Se-Hwan;Kim, Jin-Young;Kim, Piljae;Kwon, Yongju;Kim, Jungwoo;Kim, Ye Ji;Min, Jeong Ki;Kim, Ah Reum
    • Journal of Korean Society on Water Environment
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    • v.33 no.6
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    • pp.626-639
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    • 2017
  • Based on an ecological monitoring in a Korean stream (Gapyeong), Habitat Suitability Index (HSI) of nine fish species was developed for three physical habitat factors : current velocity, water depth and substrate. The species were chosen based on their abundance and frequency in the fish community of the Gapyeong stream. The Weibull model was used as the probability density function to analyze the distribution and number of each fish species according to the three identified physical factors, which showed good results. This HSI equation has advantages because it statistically expresses habitat preferences of fish species simply and clearly. From that, we can quantitatively deduce the central tendency and variation of environmental factors for fish distribution. The selected fish species showed different preferences for each habitat factor respectively. Although there are some exceptions, the distribution and abundance of individual species of nektonic fish (Zacco koreanus, Zacco platypus, Microphysogobio longidorsalis and Pungtungia herzi) were positively skewed to deep water and fine substrate while riffle-benthic fish (Koreocobitis rotundicaudata and Coreoleuciscus splendidus) were normally distributed at the shallow and coarse substrate zone. It seems that the species showing the positively skewed distribution to the current, Z. koreanus, Z. platypus, M. longidorsalis and P. herzi have adapted themselves to the fast current and have expanded their niche.