• 제목/요약/키워드: Dispersal

검색결과 325건 처리시간 0.025초

Observations on seaweed attachment to bivalve shells in Peter the Great Bay (East Sea) and their taphonomic implications

  • Lutaenko, Konstantin A.;Levenets, Irina R.
    • 한국패류학회지
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    • 제31권3호
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    • pp.221-232
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    • 2015
  • Observations in beach, intertidal and upper subtidal environments in Peter the Great Bay (north-western East Sea) have shown that attached algae were found on empty shells of 13 species of epifaunal and infaunal bivalve mollusks. Thirteen algae species were identified on empty dislodged shells but more than 50 species are known to be epibiotic on living bivalves. The dislodgement of shells with attached algae takes place in semi-enclosed, low-energy areas, as well as those which are open and affected by strong wave action, indicating the large scale of this phenomenon. The significance of seaweed transportation of living mollusks and their empty shells in the coastal zone, involving both taphonomic and ecological processes, is stressed. Algae appear to be a taphonomic agent and play a similar role as compared to birds or hermit crabs, but they act passively and contribute to environmental mixing in death assemblages in coastal environments.

소척추동물군집에서 개체군 변동과 생물다양성 유지를 위한 서식지 이질성의 기능 (Function of Habitat Heterogeneity for the Biodiversity and Demography of Population in Small Mammal Community)

  • Lee, Sang Don
    • The Korean Journal of Ecology
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    • 제18권4호
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    • pp.512-523
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    • 1995
  • The central theme of Habital heterogeneity is to provide animals with habital complexity or structural diversity and to allow resource partitioning among individuals. In turn, the leads to population stability because prey can escape more easily with more hiding places causing less population fluctuation. Species diversity is characterized due to more potential niches both horizontally and verticall. Empirically, in homogeneous habitats population was less abundant, reproduction and survival were lower, spacing behavior, competition and dispersal were higher than in heterogeneous habitats. The results imply that diversity and conservation of species can be maintained through providing heterogeneous habitats.

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프랑스 지역개발정책의 변천과 농촌 개발정책의 제유형 (The Evolution of the Regional Development Policy and Types of the Rural Development Policies in France)

  • 오현석
    • 농촌지도와개발
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    • 제4권2호
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    • pp.431-442
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    • 1997
  • The purpose of this study is to examine France's regional development policy in terms of rural development since the end of World War II. Following decentralization in 1982, France's regional and rural development policies have been focused on the interrelated actions of government, local authorities and European authorities. The aim of their works was to extend the dispersal of industrial activities to the reorganization of the rural space. The rural development policies aimed to the agricultural modernization in the 1950s have differed in their goals, methods, and implements. France's regional and rural development clearly illustrates the key role played by the government despite the decentralization and the challenges of the europeanization leading to a unique market of European nations. This reinforces the fact that the government is instrumental in organizing population distribution and regulating regional decision centers to harmonize both national objectives and local authorities' concerns. The French experience will be helpful as reference in the field of regional and rural development for Korea which has recently begun decentralizing.

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Species Associations with Spatial Autocorrelation Analysis of Pinus rigida and Pyrola japonica

  • Huh, Man-Kyu;Huh, Hong-Wook;Kim, Chang-Ho
    • The Korean Journal of Ecology
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    • 제22권6호
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    • pp.349-354
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    • 1999
  • The spatial distributions of allelic frequencies and ecological traits by randomization were studied in the natural population of two species (Pinus rigida and Pyrola japonica). Both species showed significant positive spatial autocorrelation as measured by Moran's I. In P. rigida, the genetic similarity was shown in individuals within up to a scale of 18 m distance and this is partly due to combination of pollen and seed dispersal by wind or men. In P. japonica, significant spatial autocorrelation was consisted of a scale of 8 m intervals. These population structure in the distribution of allelic frequencies is related to mating systems such as outcrossing and vegetative spread. The results also indicate that positive species associations between P. rigida and P. japonica can occur when both species select the same habitat or require the same environmental conditions.

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서울지방의 솔잎혹파리 분포조사 (The distribution of the Pine Gall-midge(Thecodiplosis japonensis UCHIDA et INOUYE) in Seoul district)

  • 고제호
    • 한국응용곤충학회지
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    • 제4권
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    • pp.55-58
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    • 1965
  • 본문은 서울을 중심으로 한 주요교통로를 따라 솔칠혹파리의 피해선단지를 조사한 것이다. (1) 서울지방의 술잎혹파리 피해는 광주, 양수, 서파, 봉천, 고촌 등 동북방으로 널리 전파되어 있다. (2) 솔잎혹파리의 전파를 조장하는 인자로는 성충기의 향이 가장 관계가 깊은 것으로 관찰되었다. (3) 솔잎혹파리 피해선단지의 유충기생봉 솔잎혹파리 좀벌의 기생율은 서파의 $13.6\%$를 제외하고는 매우 높았다.

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울릉도의 귀화식물 분포 (The Distribution of non-native Plants in Ulleung Island)

  • 박수현;고강석;길지현
    • 한국자원식물학회지
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    • 제19권2호
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    • pp.237-242
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    • 2006
  • Non-native flora of the Ulleung island, located in the eastern part of South Korea, was surveyed as 54 taxa with 16 families, 35 genera, 53 species and 1 variety. Considering the geographical distribution aspects of the island, the flora of the island showed more closely related with Korean Peninsular than Japan. Poaceace (28%) and Asteraceae (24%) represents more than 50% of the non-native flora in Ulleung island, meaning that they have an advantage of seed dispersal and adaptation to new environments. Ulleung island is comparatively small island of vulnerable to the attack of invasive alien plants but presently, it has the least number of non-native plants than other areas in South Korea. Therefore, we need to take much interest in prevention and mitigation of non-native plant in the future.

The Analysis on Forest Fire Occurrence Characteristics by Regional Area in Korea from 1990 to 2014 Year

  • Jeon, Bo Ram;Chae, Hee Mun
    • Journal of Forest and Environmental Science
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    • 제32권2호
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    • pp.149-157
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    • 2016
  • Understanding regional characteristics in forest fire occurrence is important to establish effective forest fire prevention policy in Korea. This study analyzed the characteristics of forest fires occurred in 16 administrative districts for recent 25 years (1990~2014) to examine regional characteristics in forest fire occurrence. Forest fire occurrence reflects regional characteristics depending on climatic factors as well as region's society-cultural factors. Results showed that the first cause of forest fire occurrence was carelessness by human activities throughout all administrative districts, however, the second cause depends on regional characteristics. As the results of forest fire occurrence period analyzed for 10 days, the most forest fires occurred in the southern region during January to March, while forest fires in the northern region occurred mostly during March to April. We classified forest fire occurrence patterns into three types (centralized: Gyeonggi-do, dispersal: Busan, horizontally distributed: Gyeongsangnam-do) by multi-temporal analysis for forest fire occurrence period.

한 관성 회피자와 두 비관성 추적자 간의 접근 미분 게임 (Differential Game of Approach with an Inertial Evader and Two Noninertial Pursuers)

  • 남동경;서진헌
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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    • pp.213-215
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    • 1995
  • This paper is concerned with a coplanar pursuit-evasion game of one inertial evader and two identical noninertial pursuers. The terminal time is fired and the payoff is the distance between the evader and the nearest pursuer when tile game is terminated. The value functions and the strategies is constructed for all the game surface. To get a value function, we use the generalization of the Bellman-Isaacs fundamental equation.

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Identification and Characterization of Bull Sperm Hyaluronidase Hyal5

  • Kim, Ekyune;Chang, Kyu-Tae
    • Reproductive and Developmental Biology
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    • 제35권4호
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    • pp.491-498
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    • 2011
  • During mammalian fertilization, germ cell-specific hyaluronidases, such as sperm adhesion molecule 1 (SPAM1) and hyaluronoglucosaminidase 5 (Hyal5), are important for the dispersal of the cumulus mass. In this study, we demonstrated that bull Hyal5 is a single copy gene on chromosome 4 that is expressed specifically in the testis. In addition, we expressed recombinant bull SPAM1 and Hyal5 in human embryonic kidney 293T cells and showed that these enzymes possessed hyaluronidase activity. We also demonstrated that a polyclonal antibody against bull sperm hyaluronidase inhibits sperm-egg interactions in an in vitro fertilization (IVF) assay. Our results suggested that bull Hyal5 may have a critical role in bull fertilization.

TEMPORAL VARIATIONS OF NO2 DISTRIBUTION OVER AN URBAN AREA MEASURED BY IMAGING DIFFERENTIAL OPTICAL ABSORPTION SPECTROSCOPY

  • Lee, Han-Lim
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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    • pp.302-305
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    • 2007
  • During the CareBeijing campaign in September 2006, Imaging Differential Optical Absorption Spectroscopy (IDOAS) measurements were made over the city of Beijing, China using a spatial resolution of 146 pixels horizontally and 61 pixels vertically, each with a field of view of $0.133^{\circ}$ and $0.072^{\circ}$ in the horizontal and vertical directions, respectively. Using Fraunhofer reference spectra (FRS) for the evaluation of data for two consecutive days, the diurnal variation of $NO_2$ distributions was determined from data measured every single hour from 08:00 until 16:00 on September 9 and 10. Both days presented a fairly clear sky with high visibility. The setup allowed detailed images of the low surface $NO_2$ distribution over Beijing. Images with less than a 30-min temporal resolution showed variation of plume dispersal in both horizontal and vertical directions. An in-situ measurement was also conducted. Results from both instruments are interpreted by considering local emission sources and wind conditions.

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