• Title/Summary/Keyword: polar

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Potato Soft Rot Caused by Psychrotolerant Pseudomonas sp. from Subarctic Tundra Soil

  • Sungho Woo;Yung Mi Lee;Dockyu Kim
    • Research in Plant Disease
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    • v.29 no.4
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    • pp.399-404
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    • 2023
  • Agricultural activities and the number of farms in the subarctic regions have been increasing annually after the coronavirus disease 2019 pandemic to achieve food self-sufficiency. Potatoes are vulnerable to soft rot bacteria at all stages of production, storage, and transportation. A novel bacterium, Pseudomonas sp. N3-W, isolated from Alaska tundra soil, grows at 5-25℃ and produces extracellular protease(s). N3-W caused necrotic spots (hypersensitivity) in hot pepper leaves and soft rot disease (pathogenicity) in potato tubers. The psychrotolerant N3-W caused significant soft rot symptoms on potatoes at a broad temperature range (5℃, 15℃, and 25℃). In contrast, mesophilic Pectobacterium carotovorum KACC 16999 induced severe rotting symptoms in potatoes at their optimal growth temperature of 15℃ and 25℃. However, it barely produced symptoms at 5℃, which is the appropriate storage and transportation temperature for potatoes. The results of pathogenicity testing imply that psychrotolerant soft rot pathogens from polar regions may cause severe soft rot not only during the crop growing season but also during storage and transportation. Our study indicates the possibility of new plant pathogen emergence and transmission due to the expansion of crop cultivation areas caused by permafrost thawing in response to recent polar warming.

Investigation of anti-wear additives for synthetic esters; Amine salts of phosphonic acid

  • Hasegawa, T.;Minami, I.;Kidera, Y.;Hirao, K.;Memita, M.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.269-270
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    • 2002
  • Antiwear(AW) properties of phoshphonic acid derivatives for trimethylolpropane (TMP) esters were investigated under boundary conditions. AW effect of dialkyl phosphonates depends on polarity of base fluid. They provide good AW performance in less polar TMP esters, whereas their AW effect is not sufficient in polar TMP esters. Amine salts of phosphonic acid were developed as new AW additiνe system for TMP esters. They provide excellent AW performance even in polar TMP esters.

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Polar Wavelet Method for Efficient Similarity Search in Time Series Databases (시계열 데이터 베이스에서의 효율적인 유사 검색을 위한 Polar Wavelet 기법)

  • 이범기;강성구;이상준;이석호
    • Proceedings of the Korean Information Science Society Conference
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    • 2004.10b
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    • pp.85-87
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    • 2004
  • 유클리드 거리에 기반하여 유사한 시퀀스 검색을 하는 기법들은 각 시퀀스에서 특징을 추출하여 차원을 감소시킨 후, R-tree 같은 다차원 인덱싱 기법을 사용하여 검색을 수행한다. 본 논문에서는 시계열 데이터 베이스에서의 유사 검색 성능 향상을 위한 새로운 특징 추출 기법인 Polar Wavelet 기법을 제안한다. 이 기법은 유사 검색 시 후보 시퀀스의 개수를 줄임으로써 검색 성능을 향상시킬 수 있고, 특징 추출을 위해 시퀀스의 길이를 2$^n$으로 만들 필요가 없는 장점을 갖고 있다.

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Pulsar Polar Cap and Slot Gap Models: Confronting Fermi Data

  • Harding, Alice K.
    • Journal of Astronomy and Space Sciences
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    • v.30 no.3
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    • pp.145-152
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    • 2013
  • Rotation-powered pulsars are excellent laboratories for studying particle acceleration as well as fundamental physics of strong gravity, strong magnetic fields and relativity. Particle acceleration and high-energy emission from the polar caps is expected to occur in connection with electron-positron pair cascades. I will review acceleration and gamma-ray emission from the pulsar polar cap and associated slot gap. Predictions of these models can be tested with the data set on pulsars collected by the Large Area Telescope on the Fermi Gamma-Ray Telescope over the last four years, using both detailed light curve fitting, population synthesis and phase-resolved spectroscopy.

Macroalgal Flora of Maxwell Bay, King George Island, Antarctica: II. Rhodophyta

  • Kim, Ji-Hee;Chung, Ho-Sung;Oh, Yoon-Sik;Lee, In-Kyu
    • Ocean and Polar Research
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    • v.23 no.4
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    • pp.347-360
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    • 2001
  • This study examined the taxonomic composition of marine benthic algal flora from Maxwell Bay, King George Island, Antarctica, collected between January 1988 and January 1995. The rhodophyte specimens collected and examined included a total of 20 genera and 20 species of red algae. Of these, 2 species, Kallymenia antarctica Hariot and Pantoneura plocamioides Kylin, were recorded in Maxwell Bay for the first time. Taxonomic keys for the rhodophytes are also provided.

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