• 대한수학회보
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• 제52권4호
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• pp.1069-1076
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• 2015

In this paper, a two species competitive model with stage structure and harvesting is investigated. By using the differential inequality theory, some new sufficient conditions which ensure the permanence of the system are established. Our result supplements the main results of Song and Chen [Global asymptotic stability of a two species competitive system with stage structure and harvesting, Commun. Nonlinear Sci. Numer. Simul. 19 (2001), 81-87].

• 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.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제20회 KOSCO SYMPOSIUM 논문집
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• pp.16-25
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• 2000

The differential diffusion of two species in jet is considered. The direct photo images of $H_{2}/SF_{6}$ flame are taken and the non-react jets of $H_{2}/SF_{6}$ mixture are visualized with Rayleigh scattering method. The structures of Dual flame are found in the photography. As the volume fraction of $H_2$ in mixture is increased, the flame at side is long and as the volume fraction of $SF_{6}$ in mixture is increased, the flame at center is long. This phenomena are deduced from the non-react mixture using Rayleigh scattering method. Result show that the volume fraction in the mixture is important in differential diffusion.

• Mycobiology
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• 제30권2호
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• pp.88-92
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• 2002

Rehmannia glutinosa is a perennial medicinal plant belonging to the family Scrophulariaceae with more than 300 species known in the world, especially in temperate regions. Its roots have been used widely in Korea for medicinal purposes. However, it is commonly infected by various pathogens during storage, causing great damage to the roots, and impedes the intensive farming of the crop. Therefore, an attempt has been made to isolate and screen a resistance gene against the pathogen Fusarium oxysporum using differential display. We treated salicylic acid(SA), and isolated a resistance gene that responds to SA. As a result, we found that SA was involved in plant defense mechanism in pathogenicity tests with SA treated and non-treted plants, and we isolated a partial PR-la gene through differential display polymerase chain reaction(DD-PCR) method.

• 대한화학회지
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• 제17권2호
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• pp.122-125
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• 1973

시차열곡선에서 Pyrolusite $({\beta}-MnO_2)$의 결정 전이의 흡열 Peak를 이용하여 분석 화학적인 재현성을 검토한 결과 Pyrolusite의 량이 50mg∼450mg까지는 정량적이었다. ${\alpha}-MnO_2$는 흡열 Peak가 중첩되어 파의 분리가 불가능하였으며, ${\gamma}-MnO_2$(전해이산화망간)와 ${\delta}-MnO_2$는 오차 범위 ${\pm}5{\%}{\sim}{\pm}10{\%}$이내에서 조제시료중 Pyrolusite만을 정량할 수 있다.

• Journal of Species Research
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• 제5권3호
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• pp.503-513
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• 2016

Two unrecorded marine nematode species, belonging to genus Paracanthonchus Micoletzky, 1924, are described on the basis of the specimens collected from rocky intertidal seagrass bed on the eastern coast of Korea. Paracanthonchus macrodon (Ditlevsen, 1918) is characterized by presence of cuticular differentiation, strongly dilated gubernaculum with numerous cusps, three post-cloacal setae, and arrangement of six (4+2) precloacal supplement. Paracanthonchus kamui Kito, 1981 is distinguished from other species of the genus by having the 4.25 turns amphideal fovea, six tubular supplement, rib-shaped gubernaculums with proximally hook-shaped and distally broaden. In this study, we provide taxonomic description and illustration of two unrecorded species of the genus Paracanthonchus by differential interference contrast microscopy. This is the first report on the species of the genus Paracanthonchus from Korea.

• Fisheries and Aquatic Sciences
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• 제21권8호
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• pp.28.1-28.12
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• 2018

Intertidal macroalgae are exposed to many abiotic stress factors, and they must regularly react to changes in their environment. We used RNA-seq to describe how Porphyra umbilicalis (Rhodophyta) changes gene expression patterns to interact with different habitats. Tissue samples were taken from a typical habitat along the open-coast of the Northwest Atlantic, as well as from a rare, atypical habitat in an estuarine tidal rapid environment. Differential gene expression analyses suggest that pathogic bacteria and viruses may be a significant factor influencing the transcriptome in the human-impacted estuarine environment, but the atypical habitat does not necessarily induce more stress in Porphyra umbilicalis growing there. We found genes related to nitrogen transport are over-expressed in tissue from the open-coastal site compared to those from the estuarine site, where environmental N levels approach hypertrophic levels. Low N levels impede growth, but high levels are toxic to cells, and we use qPCR to show this species regulates expression of a putative high-affinity $NH_4{^+}$ transporter under low and high N conditions. Differences in expression of this transporter in these habitats appear to be inherited from parent to offspring and have general implications for adaptation to habitat in other species that are capable of asexual reproduction, as well as more specific implications for this species' use in aquaculture.

• Food Science and Biotechnology
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• 제16권1호
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• pp.99-103
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• 2007

The purpose of this study was to develop a simple detection method, possibly at the species-level, that allows for large-scale screening of bifidobacteria. Human fecal samples were plated on MRS-raffinose agar containing cysteine and neomycin sulfate, serving as selective pressure for bifidobacteria, and 0.003%(w/v) bromocresol green. All of the test strains grew well on this medium at $37{\pm}1^{\circ}C$, forming white colonies surrounded by yellow halos, which presented a sharp contrast against the green background. In this disc assay, the required incubation time to develop a yellowish zone varied with the species of Bifidobacterium that was tested, allowing for differential counts and easy identification at the species-level: 10-14 hr for B. bifidum, 20-22 hr for B. catenulatum and B. infantis. and 24-25 hr for B. longum and B. breve. No apparent color was observed for B. angulatum and B. adolescentis 28 hr after inoculation. To evaluate the results of pH indicator-based identification, individual isolates were subjected to a colony-PCR experiment with genus-specific primers. The amplified products from the isolates were in good accordance with those from the reference strains at a level of 95% agreement. These results suggest that the present method could be conveniently applied to cell counts, as well as to the preliminary identification of bifidobacteria from a variety of sample types including human feces, dairy products, and commercial probiotic supplements.

• 한국잡초학회지
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• 제16권3호
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• pp.194-199
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• 1996

우리 나라 논에서 발생(發生)되는 논피와 돌피 그리고 식용피에 대하여 종자(種子) 크기와 초기(初期) 생육차이(生育差異)를 비교(比較)하고, 이들에 대한 피 방제용(防除用) 제초제(除草劑) molinate, esprocarb 및 mefenacet의 효과(效果)를 처리(處理) 엽기별(葉期別)로 검토(檢討)하였다. 논피 종자(種子)의 천립중(千粒重)은 돌피의 약 3배 정도 무거웠으나 식용피의 천립중(千粒重)과는 유의차(有意差)가 없었다. 파종후(播種後) 2.5엽기(葉期)에 도달하는데 식용피는 11일(日), 논피는 13일(日), 그리고 돌피는 14일(日)이 소요(所要)되었다. Molinate, esprocarb 및 mefenacet의 처리(處理)에 대하여 돌피는 논피에 비하여 보다 감수성(感受性)을 나타내었는데, 처리(處理) 엽기(葉期)의 진전(進展)과 함께 감수성(感受性)이 감소(減少)되었다. 한편 이들 제초제(除草劑)들에 대한 식용피의 반응(反應)은 1.5엽기(葉期)와 3.0엽기(葉期)사이의 처리(處理)에서 큰 차이(差異)가 없었다. Thiocarbamate계(系)의 esprocarb은 동계(同系)의 molinate에 비하여 피속(屬)에 대한 보다 강한 활성(活性)을 보였으며, 두 약제(藥劑) 모두 유효성분(有效成分) 함량(含量)이 높은 7G 제형(劑型)이 5G 제형(劑型)에 비하여 높은 활성(活性)을 보였다. 피 속간(屬間) 제초제(除草劑)에 대한 감수성(感受性) 차이(差異)는 종자(種子)크기에 따른 차이(差異)와는 關聯이 없지만, 종자(種子)크기는 초기(初期) 생육(生育) 단계(段階)에 영향(影響)을 미치며 이 초기(初期) 생육(生育) 단계(段階)즉 처리(處理) 당시(當時)의 엽기(葉期)에 따라 감수성(感受性) 차이(差異)를 나타낸다.

• Mycobiology
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• 제37권1호
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• pp.72-76
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• 2009

To investigate the growth response of various crop species to mycorrhizal inoculation, arbuscular mycorrhizal fungi were applied to Glycine max, Vigna angularis, Senna tora, Hordeum vulgare var. hexastichon. Zea mays, Sorghum bicolor, Allium tuberosum, Solanum melongena, and Capsicum annuum. The biomass of the inoculated crops was measured every two weeks for the 12-week growth period. By measuring biomass, we calculated the mycorrhizal responsiveness of the nine crop species. Among the nine crop species, four species showed a significant response to mycorrhizal inoculation. The shoot biomasses of V. angularis, C. annuum, A. tuberosum, and S. tora significantly increased with mycorrhizal inoculation.