• 제목/요약/키워드: key evolution

검색결과 680건 처리시간 0.021초

Source Environment Feature Related Phylogenetic Distribution Pattern of Anoxygenic Photosynthetic Bacteria as Revealed by pufM Analysis

  • Zeng, Yonghui;Jiao, Nianzhi
    • Journal of Microbiology
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    • 제45권3호
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    • pp.205-212
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    • 2007
  • Anoxygenic photosynthesis, performed primarily by anoxygenic photosynthetic bacteria (APB), has been supposed to arise on Earth more than 3 billion years ago. The long established APB are distributed in almost every corner where light can reach. However, the relationship between APB phylogeny and source environments has been largely unexplored. Here we retrieved the pufM sequences and related source information of 89 pufM containing species from the public database. Phylogenetic analysis revealed that horizontal gene transfer (HGT) most likely occurred within 11 out of a total 21 pufM subgroups, not only among species within the same class but also among species of different phyla or subphyla. A clear source environment feature related phylogenetic distribution pattern was observed, with all species from oxic habitats and those from anoxic habitats clustering into independent subgroups, respectively. HGT among ancient APB and subsequent long term evolution and adaptation to separated niches may have contributed to the coupling of environment and pufM phylogeny.

Emergency Management on Internet Spread of Social Events

  • Dai, Weihui;Wang, Chunshi;Zhang, Yuan
    • Journal of Information Technology Applications and Management
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    • 제18권1호
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    • pp.41-53
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    • 2011
  • The rapid development and widespread application of Internet has provided a platform for people to participate and discuss social hotspot events. In the meantime, social events may be spread throughout the Internet more quickly and widely than they did ever before, and possibly lead to serious social problems due to opinion violence or seditious rumour. This paper analyzed the Internet spread of social events, and presented a five-stage model to describe the evolution process of that spread. Furthermore, the improved IBF algorithm was applied to extract a pruned connected graph aiming to find the key nodes and the shortest spread path for the control of that spread. After analyzing the different factors that may cause the netizens' attention, this paper concluded BBS type, the visit quantity and the opinion leader are key factors which affect the Internet spread. Based on those researches, a life-cycle emergency management methodology and the related strategies were proposed for the achievement of healthy spreading environment on Internet.

First Zoeas of Two Palaemon Species (Decapoda: Caridea: Palaemoninae) Hatched in the Laboratory

  • Yang, Hoi-Jeong
    • Animal Systematics, Evolution and Diversity
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    • 제25권3호
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    • pp.237-242
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    • 2009
  • The first zoeas of Chinese ditch prawn Palaemon gravieri (Yu, 1930) and carpenter shrimp Palaemon serrifer (Stimpson, 1860) are described and illustrated in detail based on laboratory-hatched material. They are distinguished from those of Palaemon ortmanni (Rathbun, 1902) and Palaemon pacificus (Stimpson, 1860), previously known larvae from Korean waters by the length of the rostrum and endopod of antenna, the shape of the third abdominal somite, and ornamentation of the fifth abdominal somite. Larval characters of the genus Palaemon are revised. A. provisional key to the known first zoeas of Palaemon from Korean waters is given.

First Record of the Genus Elampus (Hymenoptera: Chrysidoidea: Chrysididae) from Korea, with a Key and Checklist of Current Valid Species of Korean Chrysididae

  • Ha, Su-Bong;Lee, Seung-Gil;Kim, Jeong-Kyu
    • Animal Systematics, Evolution and Diversity
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    • 제24권1호
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    • pp.69-79
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    • 2008
  • Elampus bidens ($F\ddot{o}rster$) is reported from Korea. The genus and species are new to Korea. This species is easily distinguished by a pair of processes on apical margin of metasomal tergum III. A checklist of the 45 current valid Korean species placed in the family Chrysididae is presented. A key to subfamilies, tribes, genera of Korean Chrysididae is also provided.

First Record of the Genus and Species, Entomognathus brevis (Hymenoptera: Crabronidae: Crabroninae) in Korea

  • Kim, Jeong-Kyu
    • Animal Systematics, Evolution and Diversity
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    • 제35권4호
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    • pp.191-194
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    • 2019
  • The genus Entomognathus Dahlbom 1829 is recorded for the first time in the Korean Peninsula, represented by the species Entomognathus brevis (Vander Linden, 1829). This species is trans-Palearctic in distribution ranging from northern Africa, through Europe, eastward to the Far East, and sole representative of the genus in the Far East. Of which occurrence in the Russian Far East, northern China and Japan were well documented, but nothing has been known so far in the Korean Peninsula. In this study, distributional range of E. brevis is expanded to South Korea in the Far East. Taxonomic information of the species and a revised key to genera of the tribe Crabronini occurring in the Korean peninsula are given.

Earthquake safety assessment of an arch dam using an anisotropic damage model for mass concrete

  • Xue, Xinhua;Yang, Xingguo
    • Computers and Concrete
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    • 제13권5호
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    • pp.633-648
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    • 2014
  • The seismic safety of concrete dams is one of the important problems in the engineering due to the vast socio-economic disasters which may be caused by collapse of these infrastructures. The accuracy of the risk evaluation associated with these existing dams as well as the efficient design of future dams is highly dependent on a proper understanding of their behaviour due to earthquakes. This paper develops an anisotropic damage model for arch dam under strong earthquakes. The modified Drucker-Prager criterion is adopted as the failure criteria of the dynamic damage evolution of concrete. Some process fields and other necessary information for the safety evaluation are obtained. The numerical results show that the seismic behaviour of concrete dams can be satisfactorily predicted.

Mechanical and acoustic behaviors of brine-saturated sandstone at elevated temperature

  • Huang, Yan-Hua;Yang, Sheng-Qi
    • Geomechanics and Engineering
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    • 제17권2호
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    • pp.215-225
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    • 2019
  • The mechanical behavior of rock is essential to estimate the capacity and long-term stability of $CO_2$ storage in deep saline aquifers. As the depth of reservoir increases, the pressure and temperature that applied on the rock increase. To answer the question of how the confining pressure and temperature influence the mechanical behavior of reservoir rock, triaxial compression experiments were carried out on brine-saturated sandstone at elevated temperature. The triaxial compressive strength of brine-saturated sandstone was observed to decrease with increasing testing temperature, and the temperature weakening effect in strength enhanced with the increase of confining pressure. Sandstone specimens showed single fracture failures under triaxial compression. Three typical regions around the main fracture were identified: fracture band, damaged zone and undamaged zone. A function was proposed to describe the evolution of acoustic emission count under loading. Finally, the mechanism of elevated temperature causing the reduction of strength of brine-saturated sandstone was discussed.

A New Cyclopinid Species of the Rarely Known Genus Cyclopinopsis (Copepoda, Cyclopinidae) from Korea

  • Lee, Jimin;Chang, Cheon Young
    • Animal Systematics, Evolution and Diversity
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    • 제35권3호
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    • pp.114-122
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    • 2019
  • A new species belonging to the genus Cyclopinopsis Smirnov, 1935 (Cyclopinidae) is described from Korea, as the third species of the genus. Specimens were collected by washing the subtidal sediments off Dokdo Island in the East Sea and the intertidal sands at Baegripo beach, Taean Peninsula on the Yellow Sea coast. Cyclopinopsis deformata n. sp. is characteristic and distinguished from its two congeneric species currently recognized, C. curticauda Smirnov, 1935 and C. brasiliensis Herbst, 1955 in having a deformed seta at the outer distal corner of the third exopodal segment of leg 4. The seta is supposed to be deformed from an outer spine on the third exopodal segment of leg 4, which has been known as completely lost in the genus until now. A character comparison table of the three species and a key to species of the genus Cyclopinopsis are provided herein.

A New Species of the Genus Agauopsis (Acari: Halacaridae) from Jeju Island, Korea

  • Shin, Jong Hak;Chang, Cheon Young
    • Animal Systematics, Evolution and Diversity
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    • 제35권2호
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    • pp.49-56
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    • 2019
  • A new marine halacarid species of the genus Agauopsis Viets, 1927 (Acari: Halacaridae) is recorded from Jeju Island, Korea. Agauopsis tetrasetosa n. sp. belongs to the microrhyncha group in sharing one ventral and three ventromedial spines on tibia of leg I, of which two ventromedial ones are adjacent to each other, with its 20 congeneric members. Agauopsis tetrasetosa n. sp. is most similar to A. miliaris Bartsch, 2005 and A. similis Bartsch, 1979 in sharing the similar chaetotaxy of legs I-IV, positions of the second and fourth dorsal setae, and non 'H'- or 'M'-shaped costae on anterior dorsal plate. However, the new species is distinguished from them by four pairs of perigenital setae in female, the relatively anterior location of gland pores on posterior dorsal plate, and three ventral spines on the tibia of leg II. We describe the new species herein, with detailed illustrations under a differential interference contrast microscope. We also make some brief comments on the affinities between the congeneric species of the microrhyncha group and the new species, based on a tabular key to species of the group.

Device to Device Communications Architectures and Cross-Layer Evaluation Frameworks

  • Aldabbagh, Ghadah
    • International Journal of Computer Science & Network Security
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    • 제21권1호
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    • pp.152-161
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    • 2021
  • The paper focuses on Device-to-device (D2D) Architectures evaluation frameworks. D2D communication and discovery can improve spectrum usage efficiency and optimize the tradeoffs between throughput and energy consumption. The target operation modes involve both indirect communication between two nodes via a base station or the direct communication among proximal nodes, enabling use cases that can support communications out of cellular coverage, as well as low end-end delay requirements. The paper will present the architectural evolution of D2D networks within 3GPP standardization and will highlight key network functionalities and signaling protocols. It will also identify key analytical and simulation models that can be used to assess the performance and energy efficiency of resource allocation strategies, and it will present a suitable cross-layer integrated framework.