• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.287-295
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• 2021

In this study, we aimed to evaluate the impact of different feed withdrawal periods (2, 3, 4, 5, and 6 h) on Salmonella contamination in the crop, intestinal weight, and blood parameters of broilers before harvesting. A total of 100 broilers (initial live weight 1.906±0.06 kg) were randomly assigned to the same five treatment groups and broilers had access to water but no feed before catching. Feed withdrawal times were 2, 3, 4, 5, and 6 h prior to slaughter. Measurements included live weight, pre-slaughter weight, carcass weight, weight of gastrointestinal tract. In addition, Salmonella and Campylobacter contamination in the crop, serum biochemical profiles, counts of leukocytes, erythrocytes, and platelets, and meat quality were assessed. The results demonstrate that carcass weight, blood corticosterone, meat pH, meat color, and water holding capacity did not differ based on the feed withdrawal time. Carcass yield increased as the withdrawal time increased, but the weights of the crop, proventriculus, jejunum, ileum, and rectum were significantly reduced by 6 h (P<0.05). Salmonella counts were the lowest in the crops subjected to 6 h of feed withdrawal (P<0.05). Shear force was highest in chicken breast meat after 6 h of feed withdrawal (P<0.05). However, when the feed was withdrawn after 6 h, the shear force increased, but it did not affect the sensory characteristics in consumers, and the Salmonella count also decreased and had a reduction effect on contamination during slaughter. These findings can serve as reference data for setting the feed withdrawal time.

• Cross-Cultural Studies
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• v.48
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• pp.67-106
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• 2017

This study focuses on two specific history of Korean literature in Chinese: the outline of The History of Joseon Literature (2010) by Li Yan and The History of Joseon Literature (1988, 2008) by Wei Xu-sheng; it was conducted to compare narrative viewpoints to the history of South and North Korean literature and therefore identify distinguishable characteristics. As a result, the following was concluded. First, The History of Korean Literature by Cho Dong-il and The History of Korean Literature in North Korea (15 volumes) include thorough discussions on division of historical eras, concept of genres as well as individual literary works and applied such discussions on writing literary history. However, Wei Xu-sheng and Li Yan's The History of Korean Literature did not illuminate theoretical discussion of South and North Korea. Li Yan's outline of The History of Joseon Literature was published in 2010 and the first edition of Wei Xu-sheng's The History of Joseon Literature was published in 1986 and later was published as revised editions in 2000 and 2008. Regarding published dates, it is a matter of course to reference Cho Dong-il's The History of Korean Literature, published in the 1980s, or The History of Korean Literature in North Korea (15 volumes), published in the 1990s; nevertheless, neither Wei Xu-sheng nor Li Yan used those texts in their works. Their works were heavily influenced by the narrative tradition of the history of national literature and therefore, entailed unsophisticated discussion on the division of historical eras or the concept of genres. Second, those two texts also emphasized external factors such as politics, society, economy and culture and explicitly mention these factors in historical overview of each chapter. Such an approach is commonly used in narratives of literary history under socialist regimes, including The History of Korean Literature in North Korea (15 volumes). Accordingly, evaluations based on 'political standards' - stress of people, nationality, practicality and so forth - in main texts are particularly accentuated, akin to narratives of literary history under socialist regimes. Finally, since those two Korean literature history works are written by Chinese scholars, they focus on correlation between Chinese literature history and Korean literature history. However, several genre-related terminologies such as Xiaopin (a kind of essay), Yuefu (a kind of popular song/poem), Yuyan (fable), Shuochang (telling of popular stories with the interspersal songs), Shizhuan (biography or/and memoirs in history) were adopted directly from Chinese literature. In analyzing Korean literature using terminologies introduced from Chinese literature, differences between original and alternative definitions were not examined in detail. While some terminologies and concepts were adopted directly without further consideration as to state of the two nations, it is also interesting to note that dichotomy, mainly used in Korean literature history, was used to discuss the genre of Cheonki (romance tale), relevant to Suyichon and Keumosinhua, rather than follow traditions of Chinese literature history.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.1
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• pp.41-52
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• 2022

As a cultivar of Korean wheat, 'Keumgang' wheat variety has a fast growth period and can be grown stably. Hexaploid wheat (Triticum aestivum) has moderately high salt tolerance compared to tetraploid wheat (Triticum turgidum L.). However, the molecular mechanisms related to salt tolerance of hexaploid wheat have not been elucidated yet. In this study, the candidate genes related to salt tolerance were identified by investigating the genes that are differently expressed in Keumgang variety and examining salt tolerant mutation '2020-s1340.'. A total of 85,771,537 reads were obtained after quality filtering using NextSeq 500 Illumina sequencing technology. A total of 23,634,438 reads were aligned with the NCBI Campala Lr22a pseudomolecule v5 reference genome (Triticum aestivum). A total of 282 differentially expressed genes (DEGs) were identified in the two Triticum aestivum materials. These DEGs have functions, including salt tolerance related traits such as 'wall-associated receptor kinase-like 8', 'cytochrome P450', '6-phosphofructokinase 2'. In addition, the identified DEGs were classified into three categories, including biological process, molecular function, cellular component using gene ontology analysis. These DEGs were enriched significantly for terms such as the 'copper ion transport', 'oxidation-reduction process', 'alternative oxidase activity'. These results, which were obtained using RNA-seq analysis, will improve our understanding of salt tolerance of wheat. Moreover, this study will be a useful resource for breeding wheat varieties with improved salt tolerance using molecular breeding technology.

• Journal of Korean Society of Forest Science
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• v.14 no.1
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• pp.1-20
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• 1972

The trend and achievements of forest genetics research in abroad were investigated through observation tours and reference work and following facts were found to be important aspects which should be adopted in the forest genetics research program in Korea. Because of world wide recognization on the urgency of taking a measure to reserve some areas of the representative forest type on the globe before the extingtion of such forest type as the results of continuous exploitations of the natural forests to meet the timber demand all over the world, it is urgently needed to take a measure to reserve certain areas of natural stand of Pinus koraiensis, Pinus parviflora, Pinus densiflora f. erectra, Abies koreana, Quercus sp., Populus sp., etc. as gene pool to be used for the future program of forest tree improvement. And the genetic studies of those natural forest of economic tree species are also to be performed. 1. Increase of the number of selected tree for breeding purpose. Because of the fact that the number of plus tree at present is too small to carry out selection program for tree improvement, particularly for the formation of source population for recurrent selection of parent trees of the 2nd generation seed orchard it is to be strongly emphasized to increase the number of plus tree by alleviating selection criteria in order to enlarge the population size of plus trees to make the selection program more efficient. 2. Progeny testing More stress should be placed on carrying out progeny testing of selected trees with open pollinated seeds. And particular efforts are to be made for conducting studies on adult/juvenile correlation of important traits with a view to enable to predict adult performances with some traits revealed in juvenile age thus to save time for progeny testing. 3. Genotype-environment interaction Studies on genotype and environment interaction should be conducted in order to elucidate whether the plus trees selected on the good site express their superiority on the poor site or not and how the environment affect the genotype. And the justification of present classification of seed distribution area should be examined. 4. Seed orchard of broad leaf tree species. Due to the difficulty of accurate comparison of growth rate of neighbouring trees of broad leaf tree species in natural stand, it is recommended that for the improvement of broad leaf trees a seedling seed orchard is to be made by roguing the progeny test plantation planted densely with control pollinated seedlings of selected trees. 5. Breeding for insect resistant varieties. In the light of the fact that the resistant characteristics against insect such as pine gall midge (Thiecodiplosis japonensis U. et I.) and pine bark beetle (Myelophilus pinipera L.) are highly correlated with the amount and quality of resin which are known as gene controlled characteristics, breeding for insect resistance should be carried out. 6. Breeding for timber properties. With the tree species for pulp wood in particular, emphasis should be placed upon breeding for high specific gravity of timber. 7. Introduction of Cryptomeria and Japanese Cypress In the light of the fact that the major clones of Cryptomeria are originated from Yoshino source and are being planted up to considerably north and high elevation in Japan, those species should be examined on their cold resistance in Korea by planting them in further northern part of the country.