• Title/Summary/Keyword: Niche

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Fish Community and Stream Health Assessment in Lake Chungju and its Tributaries (충주호의 어류상과 유입하천의 생태건강성 평가)

  • Choi, Myung-Jae;Park, Hae-Kyung;Yun, Seuk-Hwan;Lee, Jangho
    • Journal of Korean Society on Water Environment
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    • v.28 no.2
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    • pp.185-196
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    • 2012
  • The fish community within the lake and 5 tributaries of Lake Chungju in spring and autumn, 2009 was surveyed. In this study, the total 128,506 individuals were collected belonging to 11 families 29 genera 34 species. The most dominant species was Squalidus japonicus coreanus that account for 91.6% of population and 49% of biomass of fish community. In the point of population, dominant species were small-sized species, which became the prey of big-sized predatory species. In the point of biomass, dominant species were predatory species which were large-sized. The most dominant species in lacustrine area was S. japonicus coreanus which accounted for 92.2% of total population and 49.1% of total biomass. The most dominant species of tributary streams was Tridentiger brevispinis which accounted for 66.4% of total population and 55.1% of total biomass. The site of C3 in lacustrine area and Dongdal-cheon in tributary streams collected the most number of species. Through ecological health evaluation of five tributary streams using 8 metric index of biological integrity (IBI) model, two streams (Dongdal-cheon, Kwang-cheon were evaluated as, "B", "good" condition, and Jangsung-cheon obtained grade C indicating "Fair" condition, Jecheon-cheon obtained grade D indicating "Poor" condition based on IBI model. Lepomis macrochirus which was designated as a domestic ecosystem-disturbing alien species with wide food niche have shown tendency to increase the number of individuals since 1991 indicating the adverse effect on not only fish community but also aquatic ecosystem food web of Lake Chungju.

What Is to Be Done with Creative Ecosystem Based on Creative Economic Innovation Center: An Implication through Comparing Silicon Valley and Kyoto Eco-system (창조경제혁신센터형 창조생태계 어떻게 할 것인가?: 실리콘 밸리 및 교토생태계와의 비교를 통한 시사점)

  • Lee, Hong
    • Journal of Technology Innovation
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    • v.25 no.4
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    • pp.145-164
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    • 2017
  • This research targeted discussions on re-utilization of Korean creative economic innovation center. It is meaningless to simply discuss its re-organization. The focus of this study was to find a way that transforms it into totally new one. The study followed several steps. First, it delineated criteria from existing literature for comparing creative eco-system of Silicon valley, Kyoto eco-system and eco-system based on Korean creative economic innovation center. Second, it compared the three eco-systems in details. Third, it discussed a direction for transforming eco-system based on Korean creative economic innovation center. It was suggested that the Kyoto eco-system can be a role model. It was also suggested that governmental role should be changed from controller to facilitatior which stimulates regulation relaxations and helps to establish market formation.

Feeding Habits of the Marbled Flounder, Peluronectes yokohamae in the Coastal Waters off Tongyeong, Korea (통영주변해역에 서식하는 문치가자미(Pleuronectes yokohamae)의 식성)

  • Huh, Sung-Hoi;Nam, Ki-Mun;Park, Joo-Myun;Jeong, Jae-Mook;Baeck, Gun-Wook
    • Korean Journal of Ichthyology
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    • v.24 no.2
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    • pp.77-83
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    • 2012
  • The feeding habits of the marbled flounder Pleuronectes yokohamae were studied using 395 specimens collected from January to December, 2010, in the coastal waters off Tongyeong, Korea. The size of P. yokohamae ranged from 10.5 to 38.8 cm in standard length (SL). P. yokohamae is a bottom-feeding carnivore that consumes mainly bivalves, amphipods and polychaetes. Its diet also includes small quantities nemertians, anthozoan, isopods, copepods, tanaidacean, shrimps, crabs and ophiuroids. Our feeding-strategy graphical method reveled that P. yokohamae was a generalized feeder, with a wide niche width. P. yokohamae mainly consumed bivalves, amphipods and polychaetes, and did not show significant ontogenetic changes in feeding habit without size over 22 cm. Prey size did not increase significantly as growing fish size.

Preference of the Rice Weevil (Coleoptera: Curculionidae) for the Storage Mold Contaminated Brown Rice (저장곰팡이 오염 현미에 대한 쌀바구미의 선호성)

  • 윤태중;윤은영;이승빈;박미경;류문일
    • Korean journal of applied entomology
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    • v.42 no.4
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    • pp.329-334
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    • 2003
  • To study the interaction between rice weevil and storage molds, the preference of rice weevil to the four mold species (Aspergilus candidus, A. niger, A. flavus and Penicillium spp.) and the resulting reproduction of the rice weevil were observed. The rice weevil preferred rice grains contaminated with the molds to autoclaved ones regardless of the mold species tested. Among the four mold species, A. candidus and Penicillium sp. were highly preferred than the others. Reproduction of the rice weevil was higher on the grains contalminated with A. candidus and Penicillium sp., than on autoclaved ones, but was lower on the grains contaminated with A. flavus. The partial disagreement between preference and reproduction of the rice weevil might be a suggestion that both the weevil behavior adapting nutritional requirements and the process of the long intensive coadaptation of the rice weevil and storage molds requiring similar moisture niche are the major components of the population interaction between the weevil and molds.

ACUTE RESPONSE OF THE RAT INCISOR BY SINGLE AND FRACTIONATED IRRADIATION (단일 및 분할 방사선조사에 의한 백서절치의 급성반응에 관한 연구)

  • Rhee In-Suk;Park Tae-Won;Ahn Hyung-Kyu
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.19 no.1
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    • pp.39-48
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    • 1989
  • Six to eight-month-old female albino rats were used as experimental animals. As an irradiation equipment, a Co-60 was used. The experimental animals were divided to; 6 of the control group, 12 of the 500cGy single irradiation group, 12 of the 1000cGy fractionated irradiation group, and 12 of the 1500cGy fractionated irradiation group. From the first week to the forth, 3 rats were picked from each group every week to be sacrificed and fixed with formalin. Those rats were observed by means of H-E stain after being taken radiograph and decalcified. The analysis of radiographic findings and light microscopic findings gives results as follows: 1. The delay of dental eruption rate was found in every group which underwent the irradiation experiment. Dentin niche, osteodentin, and dentin island were formed in the parts which were damaged by the irradiation. 2. The longer the observation period was, the more deposit of osteodentin and dentin island was formed. 3. In the single irradiation group, the damage effect was in proportion to the increase of radiation dose, whereas the damage was much less in the fractionated group receiving the same dose. 4. The 500cGy single irradiation group got temporary repairable damage, while the 1000cGy single irradiation group got considerable damage and showed much slower eruption rate than the 500cGy single irradiation group. The basal portion of the 1500cGy single irradiation group, whose growth was arrested, was destroyed. 5. The fractionated group were irradiated 500cGy everyweek. Repair was visible during the interval periods. The damage was accumulated as irradiation repeated, but degree of damage was lower than that of the 1000cGy and 1500cGy single irradiation group.

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Study on Competitive Fighting Game SSF4 Han Ju-Ri's Fashion (대전격투게임 SSF4의 한주리 (Han Ju-Ri, 韓蛛俐) 의상에 대한 연구)

  • Yoon, Kyoung Hee;Cho, Woo Hyun
    • Journal of the Korean Society of Costume
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    • v.63 no.7
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    • pp.121-133
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    • 2013
  • The globalization of the world, fueled by the Internet, made possible for individuals to access the cultures around the world, other than their own, easier than ever before. But among those rapidly sought out sub-cultures, the video gaming industry, once a niche market mostly for nerds and geeks, now has become one of the biggest entertainment businesses in the world. In a video game, one of the critical elements that could determine its success or failure is the characters featured in the game. And as the countless number of animated characters from many different video games from the past few years have become incredibly popular among the audiences around the world, the expectations from the fans also grow higher every time a new game comes out. Ultimately this has forced the video game developers to come up with more unique and interesting characters for their video games. And at this point, where a video game character is more than just fictional fantasy but a brand to be recognized, it is worth paying proper attention to the video game characters that represent Korea. Hence in this study, we will take a look at Han Ju-Ri, a Korean character featured in Super Street Fighter IV, a competitive fighting game developed by Capcom, one of the world's most recognized video game companies that started its life as an arcade video game, developer but eventually ventured its business into the online world. The study will propose a complete overhaul of the character by incorporating Korea's own traditional looks.

Helicobacter pylori Infection and Vitamin C: Past, Present and Future Perspectives (Helicobacter pylori 감염과 비타민 C: 과거, 현재, 미래)

  • Youn, Hee-Shang;Rhee, Kwang-Ho
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.11 no.sup1
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    • pp.83-92
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    • 2008
  • Helicobacter pylori is the causative agent of chronic gastritis and has a role in the pathogenesis of peptic ulcer diseases, and gastric cancer. There have been reports suggesting a close link between these gastroduodenal disorders and a state of vitamin C deficiency. In this paper, the past, present and future perspectives on H. pylori infection and vitamin C will be discussed under the following view points. Since the ecological niche of H. pylori is the mucus layer and intercellular junctions of the gastric epithelium, the various kinds of host inflammatory cells motivated by the local and systemic immune responses cannot eliminate the microorganisms. When the invading foreign body is not removed, despite full activation of defense mechanisms, adverse consequences of the immune responses develop on the host gastric mucosa. The reasons for the body vitamin C depletion could be explained as follows; 1) the increased vitamin C consumption by increased oxygen free radical production through the prolonged hypersensitivity reactions in the gastric mucosa, 2) the increased vitamin C oxidation by the nitrite which is formed from nitrate reduction by the intragastric bacteria proliferated in the hypochlorhydric gastric cavity, 3) the strong ${\gamma}$-glutamyltranspeptidase activity of H. pylori which depletes the glutathiones in gastric mucosa. Depletion of glutathiones in the stomach favors irreversible oxidative destruction of ascorbic acid. Both persistent inflammatory burdens in the stomach by H. pylori and resultant vitamin C depletions synergistically and uninhibitedly might aggravate the hypothetical sequence of gastric carcinogenesis: atrophic gastritis${\rightarrow}$intestinal metaplasia${\rightarrow}$dysplasia${\rightarrow}$gastric adenocarcinoma. High intake of vitamin C could reverse the hypothetical sequence of the gastric carcinogenesis via direct and indirect effects on H. pylori and host-parasite relationships.

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A Simulation Model for the Study of the Territorial Behavior of Subterranean Termites (흰개미 테리토리행동 연구를 위한 시뮬레이션 모델)

  • Jeon, Won-Ju;Lee, Sang-Hee
    • Journal of the Korea Society for Simulation
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    • v.21 no.2
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    • pp.1-9
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    • 2012
  • Subterranean termites forage by constructing tunnel networks in soil and encounter food resources during tunnel excavation. Some species of termites can travel up to 150 m underground. They often travel to the surface to find wood cellulose to feed their colony, which in turn causes extensive damage to wooden architecture, such as timber-frame houses. This type of damage has been constantly increasing along with global warming because higher temperatures provide an ecological niche for termites. The damage is closely related to termite territory size and distribution. Recently, as a way to research termite control, the necessity of a mathematical model to simulate termite territory formation in relation to damage has increased. So far, however, few studies have been conducted on the development of a model because it is difficult to quantify or characterize the relationship between territorial behavior and field conditions including complicated environmental factors. In the present study, we suggest a simulation model of the territoriality of the Formosan subterranean termites, Coptotermes formosanus (Shiraki), and Reticulitermes flavipes (Kollar), based on empirical data. The model consists of 2 procedures. One describes tunnel network growth for each colony, and the other represents territoriality based on tunnel-tunnel interactions between different colonies. Using the model, we show changes in territorial competition according to the termination probability of tunnel growth.

Caenorhabditis elegans: A Model System for Anti-Cancer Drug Discovery and Therapeutic Target Identification

  • Kobet, Robert A.;Pan, Xiaoping;Zhang, Baohong;Pak, Stephen C.;Asch, Adam S.;Lee, Myon-Hee
    • Biomolecules & Therapeutics
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    • v.22 no.5
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    • pp.371-383
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    • 2014
  • The nematode Caenorhabditis elegans (C. elegans) offers a unique opportunity for biological and basic medical researches due to its genetic tractability and well-defined developmental lineage. It also provides an exceptional model for genetic, molecular, and cellular analysis of human disease-related genes. Recently, C. elegans has been used as an ideal model for the identification and functional analysis of drugs (or small-molecules) in vivo. In this review, we describe conserved oncogenic signaling pathways (Wnt, Notch, and Ras) and their potential roles in the development of cancer stem cells. During C. elegans germline development, these signaling pathways regulate multiple cellular processes such as germline stem cell niche specification, germline stem cell maintenance, and germ cell fate specification. Therefore, the aberrant regulations of these signaling pathways can cause either loss of germline stem cells or overproliferation of a specific cell type, resulting in sterility. This sterility phenotype allows us to identify drugs that can modulate the oncogenic signaling pathways directly or indirectly through a high-throughput screening. Current in vivo or in vitro screening methods are largely focused on the specific core signaling components. However, this phenotype-based screening will identify drugs that possibly target upstream or downstream of core signaling pathways as well as exclude toxic effects. Although phenotype-based drug screening is ideal, the identification of drug targets is a major challenge. We here introduce a new technique, called Drug Affinity Responsive Target Stability (DARTS). This innovative method is able to identify the target of the identified drug. Importantly, signaling pathways and their regulators in C. elegans are highly conserved in most vertebrates, including humans. Therefore, C. elegans will provide a great opportunity to identify therapeutic drugs and their targets, as well as to understand mechanisms underlying the formation of cancer.

Diet composition of juvenile Trachurus japonicus in the coastal waters of Geumodo Yeosu, Korea (여수 금오도 주변해역에 출현하는 전갱이 (Trachurus japonicus) 유어의 위내용물 조성)

  • KIM, Heeyong;LIM, Yu Na;JEONG, Jae Mook;KIM, Hyeon Ji;BAECK, Gun Wook
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.51 no.4
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    • pp.637-643
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    • 2015
  • The diet composition of juvenile Trachurus japonicus were studied using 195 specimens collected from 2013 (May, June, July, and September) to 2014 (May, June, and July) in the coastal waters of Geumodo, Yeosu, Korea. The size of juvenile T. japonicus ranged from 4.3 to 15.2 cm in body length (BL). Juvenile T. japonicus was carnivorous and crustaceans predators that consumes mainly consumed copepods. Its diet also included small quantities of decapods, cirripedians, nematods, chaetognathans, fishes, amphipods, cumaceans, ostracods and euphausiids. The graphical method for feeding strategy revealed that juvenile T. japonicus is an opportunistic and specialized predator on copepods, especially Corycaeus. affinis, and showed narrow niche width. Juvenile T. japonicus showed ontogenetic diet change. Small size group individuals (4.3-8.0 cm BL) mainly consumed copepods. The portion of this prey item decreased in the large size group (8.0-15.2 cm BL), and this decrease was paralleled with increased consumption of decapods.