蚜虫和蝗虫的性别决定初探     

李有泉  王海蓉 《蒙自师范高等专科学校学报》1997,(4)

XA型生物性别决定机制的特点:蚜虫的X染色体含X基因的数量小于常染色体组合的Y基因,为0.6-0.8;蝗虫的X染色体与常染色体含X基因与Y基因的数量相同,为1.0;X染色体含的X基因全都能在性别决定中起作用,会是有效性基因;常染色体组则随各种性型的X染色体与常染色体组的数量关系不同,所含的Y基因有的在性别决定中起作用,有的在性别决定中不起作用,有有效性基因和无效性基因之别。由此,决定了蚜虫须经历有性和无性两个世代,以有性和无性两种生殖来完成世代交替,靠营群居生活才能进行繁衍生息;蝗虫不再须经历有性有无性两个世代,只以有性生殖来完成世代交替,营独栖生活也能进行繁衍生自。  相似文献   

多元互补--新时期我国硕士研究生培养模式的战略选择   总被引：3，自引：0，他引：3  

王根顺  张亚丽 《高等理科教育》2006,(1):26-30

研究生扩招使得生源更加多样化;随着经济的发展,社会对硕士研究生的需求也呈现多样化的趋势;同时我国高校具有多样性和层次性的特点;研究生的布局结构也不均匀。受以上诸多因素的影响,我国的硕士研究生不宜采用单一的培养模式,应该使多元互补成为我国硕士研究生培养模式的战略选择。  相似文献   

《英语国家概况》的课程特点及教学策略   总被引：1，自引：0，他引：1  

王毅聪 《黄山学院学报》2006,8(5):133-135

《英语国家概况》是英语专业一门重要的文化知识课,是传播英语国家社会文化、培养学生跨文化交际能力的主渠道。较之于其它语言课程,该课程有自身的特点。教学中教师应针对该课程的特点,遵循文化教学的基本原则,采取有效的教学策略,从而达到较好的教学效果。  相似文献   

绿色荧光蛋白和荧光素酶     

马三梅  王永飞 《生物学教学》2005,30(12):5-6

绿色荧光蛋白和荧光素酶基因是基因工程中广泛使用的两个报告基因。本文从绿色荧光蛋白和荧光素酶的来源、性质、发光机理、检测方法和用途等方面论述了两者的区别。  相似文献   

Promoting cognitive and social aspects of inquiry through classroom discourse     

Hui Jin  Xin Wei  Peiran Duan  Yuying Guo  Wenxia Wang 《International Journal of Science Education》2016,38(2):319-343

We investigated how Chinese physics teachers structured classroom discourse to support the cognitive and social aspects of inquiry-based science learning. Regarding the cognitive aspect, we examined to what extent the cognitive processes underlying the scientific skills and the disciplinary reasoning behind the content knowledge were taught. Regarding the social aspect, we examined how classroom discourse supported student learning in terms of students' opportunities to talk and interaction patterns. Our participants were 17 physics teachers who were actively engaged in teacher education programs in universities and professional development programs in local school districts. We analyzed one lesson video from each participating teacher. The results suggest both promises and challenges. Regarding the cognitive aspect of inquiry, the teachers in general recognized the importance of teaching the cognitive processes and disciplinary reasoning. However, they were less likely to address common intuitive ideas about science concepts and principles. Regarding the social aspect of inquiry, the teachers frequently interacted with students in class. However, it appeared that facilitating conversations among students and prompting students to talk about their own ideas are challenging. We discuss the implications of these findings for teacher education programs and professional development programs in China.  相似文献   

What are you going to be when you grow up？     

周艳丽  王艳丽 《中学生英语》2006,(1):42-42

One day our teacher in charge of class （我们的班主任） calked us, “What are you going to be when you grow up？” Some of my classmates answered him at once one after another.  相似文献   

简论马克思主义人权观     

王自发 《绥化学院学报》2001,21(4):1-4

本文是从形成与发展、阶级属性、基本特征等三个主要方面综述了马克思主义人权理论体系，指出了马克思主义人权理论是无产阶级进行革命斗争的强大思想武器，对近代中国人权理论研究与政治斗争，尤其是在当前改革开放和现代化建设事业中具有重要的现实指导意义。  相似文献   

血管内皮损伤与动脉粥样硬化关系探讨   总被引：1，自引：0，他引：1  

王新生  任君旭 《河北北方学院学报(社会科学版)》2004,21(6):57-60

内皮细胞作为一种多功能细胞,为功能不同的各段血管提供共同的连接衬里.内皮细胞具有细胞通透性、选择性屏障、止血、抗凝、纤溶、血流传输和血管活性物质代谢、以及调节血管运动张力、产生生长因子、纤维基质增生等作用.这些特征可引起或参与微循环或微体循环相关的疾病过程,并与动脉粥样硬化的发生、发展存在重要关系.  相似文献   

论"楚辞"主题的战斗性   总被引：1，自引：0，他引：1  

王晋建 《武汉职业技术学院学报》2004,3(4):37-39

屈原由于其忧愤深广的爱国情怀，尤其是为了理想而顽强不屈地对现实进行批判的精神，为中国文化增添了一股深沉而刚烈之气。楚国历史上传统的战斗精神表现在屈原作品中，较之《诗经》，《楚辞》主题的战斗性大大加强了。  相似文献   

Allograftic bone marrow-derived mesenchymal stem cells transplanted into heart infarcted model of rabbit to renovate infarcted heart     

王建安  李长岭  樊友启  何红  孙勇 《浙江大学学报(A卷英文版)》2004,5(10):1279-1285

Objective: To investigate the directed transplantation of allograftic bone marrow-derived mesenchymal stem cells (MSCs) in myocardial infarcted (MI) model rabbits. Materials and Methods: Rabbits were divided into 3 groups, heart infarcted model with MSCs transplanted treatment (MSCs group, n=12), heart infarcted model with PBS injection (control group, n=20), sham operation with PBS injection (sham group, n=l 7). MSCs labelled by BrdUrd were injected into the MI area of the MSCs group. The same volume of PBS was injected into the MI area of the control group and sham group. The mortality, LVIDd, LVIDs and LVEF Of the two groups were compared 4 weeks later. Tropomyosin inhibitory component (Tn I) and BrdUrd immunohistochemistry identified the engrafted cells 4 weeks after transplantation. Result: The mortality of the MSCs group was 16.7% (2/12), and remarkably lower than the control group's mortality [35% (7/20) (P＜0.05)].Among the animals that survived for 4 weeks, the LVIDd and LVIDs of the MSCs group after operation were 1.17±0.21 cm and 0.74±0.13 cm, and remarkably lower than those of the model group, which were 1.64±0.14 cm and 1.19±0.12 cm (P＜0.05); the LVEF of the MSCs group after operation was 63±6%, and remarkably higher than that of the model group,which was 53±6% (P＜0.05). Among the 10 cases of animals that survived for 4 weeks in the MSCs group, in 8 cases (80%),the transplanted cells survived in the non MI, MI region and its periphery, and even farther away; part of them differentiated into cardiomyocytes; in 7 cases (70%), the transplanted cells participated in the formation of blood vessel tissue in the MI region. Conclusion: Transplanted allograftic MSCs can survive and differentiate into cardiomyocytes, form the blood vessels in the MI region. MSCs transplantation could improve the heart function after MI.  相似文献