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Thomas数组的再发现
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作者 郑成生 《数学学习与研究》 2019年第20期140-140,142,共2页
本文通过对Chaudhari-Deshpande数组和Thomas数组研究,提出了双色数和完美双色数的概念.
关键词 Thomas数组 双色数 完美双色数
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Total Chromatic Number of the Join of K_(m,n) and C_n
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作者 LI Guang-rong ZHANG Li-min 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2006年第2期264-270,共7页
The total chromatic number xT(G) of a graph G is the minimum number of colors needed to color the elements(vertices and edges) of G such that no adjacent or incident pair of elements receive the same color, G is c... The total chromatic number xT(G) of a graph G is the minimum number of colors needed to color the elements(vertices and edges) of G such that no adjacent or incident pair of elements receive the same color, G is called Type 1 if xT(G) =△(G)+1. In this paper we prove that the join of a complete bipartite graph Km,n and a cycle Cn is of Type 1. 展开更多
关键词 total coloring total chromatic number join graphs CYCLE complete bipartite graph
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An Action Research of Using Problem-Centered Double-Cycles Instructional Model to Implement ModeI-Elicitng Activity
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作者 Yi-Chen Yu Ching-Kuch Chang Lee-Meei Lin 《Journal of Mathematics and System Science》 2013年第12期614-624,共11页
The purpose of the study was to use the Problem-Centered Double-Cycles Instructional Model (PCDC-IM) (1995, Chang) to help the teacher (Lin) implement model-eliciting activity (MEA) in her mathematics classes.... The purpose of the study was to use the Problem-Centered Double-Cycles Instructional Model (PCDC-IM) (1995, Chang) to help the teacher (Lin) implement model-eliciting activity (MEA) in her mathematics classes. In this study, there were 31 students divided in 10 groups and engaged in the MEA "Who saved the oriental cherry trees". Data collections included the learning sheets, journals and debriefing forms of students, teaching and reflection journals, observation reports, and field notes of teachers, reflection journals and interview reports of researchers, video tapes and records of the classes and meetings. There were four parts of the teaching cycle in PCDC-IM, namely task, guidance, environment and analysis. We summarized developing and implementing the MEA in "Task" aspect, 5 principles and 5 kinds of teachers' roles in "Guidance" aspect, 2 elements and 5 features in "Environment" aspect and data in "Analysis" aspect. The findings showed that PCDC-IM was helpful for mathematics teachers who want to change their instruction from lecture into modeling teaching. 展开更多
关键词 Instructional model model-eliciting activity action research
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Adjacent Strong Edge Chromatic Number of Series-Parallel Graphs 被引量:1
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作者 王淑栋 庞善臣 许进 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2005年第2期267-278,共12页
In this paper, we will study the adjacent strong edge coloring of series-parallel graphs, and prove that series-parallel graphs of △(G) = 3 and 4 satisfy the conjecture of adjacent strong edge coloring using the doub... In this paper, we will study the adjacent strong edge coloring of series-parallel graphs, and prove that series-parallel graphs of △(G) = 3 and 4 satisfy the conjecture of adjacent strong edge coloring using the double inductions and the method of exchanging colors from the aspect of configuration property. For series-parallel graphs of △(G) ≥ 5, △(G) ≤ x'as(G) ≤ △(G) + 1. Moreover, x'as(G) = △(G) + 1 if and only if it has two adjacent vertices of maximum degree, where △(G) and X'as(G) denote the maximum degree and the adjacent strong edge chromatic number of graph G respectively. 展开更多
关键词 series-parallel graph adjacent strong edge coloring adjacent strong edge chromatic number.
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A TOP6BL mutation abolishes meiotic DNA double-strand break formation and causes human infertility 被引量:3
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作者 Yuying Jiao Suixing Fan +23 位作者 Nazish Jabeen Huan Zhang Ranjha Khan Ghulam Murtaza Hanwei Jiang Asim Ali Yang Li Jianqiang Bao Beibei Zhang Jianze Xu Bo Xu Hafiz Muhammad Jafar Hussain Qumar Zaman Ihsan Khan Ihtisham Bukhari Furhan Iqbal Ayesha Yousaf Sobia Dil Manan Khan Niaz Ahmad Hui Ma Xiaohua Jiang Yuanwei Zhang Qinghua Shi 《Science Bulletin》 SCIE EI CSCD 2020年第24期2120-2129,M0006,共11页
Meiosis is pivotal for sexual reproduction and fertility. Meiotic programmed DNA double-strand breaks(DSBs) initiate homologous recombination, ensuring faithful chromosome segregation and generation of gametes. Howeve... Meiosis is pivotal for sexual reproduction and fertility. Meiotic programmed DNA double-strand breaks(DSBs) initiate homologous recombination, ensuring faithful chromosome segregation and generation of gametes. However, few studies have focused on meiotic DSB formation in human reproduction.Here, we report four infertile siblings born to a consanguineous marriage, with three brothers suffering from non-obstructive azoospermia and one sister suffering from unexplained infertility with normal menstrual cycles and normal ovary sizes with follicular activity. An autosomal recessive mutation in TOP6BL was found co-segregating with infertility in this family. Investigation of one male patient revealed failure in programmed meiotic DSB formation and meiotic arrest prior to pachytene stage of prophase I.Mouse models carrying similar mutations to that in patients recapitulated the spermatogenic abnormalities of the patient. Pathogenicity of the mutation in the female patient was supported by observations in mice that meiotic programmed DSBs failed to form in mutant oocytes and oocyte maturation failure due to absence of meiotic recombination. Our study thus illustrates the phenotypical characteristics and the genotype-phenotype correlations of meiotic DSB formation failure in humans. 展开更多
关键词 Programmed meiotic DNA double-strand breaks TOP6BL mutation Meiotic DSB formation failure Human infertility Oocyte maturation failure Meiotic arrest
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