“加法运算定律”教学浅见

<正>小学数学运算定律是计算法则的理论基础,是学生必须掌握的基础知识,运用这些运算定律可以使一些运算更简便,正确率更高。因此,让学生牢固掌握,并灵活地应用十分重要。加法运算定律包括"加法交换律"和"加法结合律"。"加法交换律"用字母表示:a+b=b+a,用图形表示:+○=○+,用文字表示:甲数+乙数=乙数+甲数,用文字表述:"两个数相加,交换加数的位置,它们的和不变"。"加法结合律"用字母表示:a+b+c=(a+b)+c=a+(b+c),用图形表示:(○+)+△=○+(+△),用文字表示:(甲数+乙数)+丙数=甲     

课程思政理念下职业本科院校公共体育教学探究

国家正在大力推进课程思政教育改革,以进一步提升当前学生的思想政治水平。职业本科院校的公共体育课与思政教育有效结合,其意义十分重大。就职业本科院校公共体育课与思政教育相融合进行探析,全面探究目前出现的问题,从思想上重视,提升教师政治素养和鼓励学生参加社会实践等方面提出了对策。     

注重教师倦怠期的教育培养

振兴民族的希望在教育,振兴教育的希望在教师.没有一支合格的、高水平的、持续稳定发展的教师队伍,推行素质教育,提高教育质量就是一句空话.要使一个教师从走上讲台度过适应期,进入稳定期,在此基础上步入发展期,最终跨入成熟期,必须研究其成长规律,把握关键环节强化培训,制定职业生涯发展规划,做到思想认识、系统管理、检查评价三到位,使其教学专业的"学术",课堂教学的"艺术"、现代教育的"技术"三位一体整合优化.     

分子生物学教学方法初探

本文主要对分子生物学课程的教学方法进行了探讨,包括教学内容、教学方法及实验教学、教书育人等的改革、优化和实践,以期提高分子生物学的教学质量和教学效果,培养生命科学领域优秀人才,以适应现代生命科学的发展.     

芍药属的研究(1)——国产几个野生种核型的报道

In the present paper 8 species with 15 populations of the genus Paeonia L. (if P. papaveracea and P. japonica are recognised as species) were collected from Sichuan, Shaanxi and Hebei provinces (see the Appendix for detail of the materials).  The micrographs of their somatic metaphase (also Mii in the case of P.veitchii) are shown in Plates 1-4, the karyo- type formulae, ranges of chromosome length and classification of karyotypes according to Steb- bins (1971) are shown in Table 5: the idiograms in Figs. 1-2, and the parameters of chromo- somes in Table 1-4.  The essential points are mentioned as follows:        (1)   Chromosomes of the various species in the section Modan have so far been examined and they are all diploid, the two species in the section Onaepia are also diploid, and thus tetraploids exist only in the section Paeonia.        (2)  Chromosomes in the genus Paeonia are relatively stable except for the differentiation of ploidy.  The karyotypes (Table 1-4) show no differences among different taxa in Sect. Modan and the same can also be said about the taxa in Sect. Paeonia (Table 1).  Not only are the karyotypes very similar, but also among the members within  either section have the same parameters of chromosomes, and, differences, if occur, are not statistically significant. Between the two sections, however, the situation is different. The arm ratios of the first pairs of chromosomes in Sect. Modan are 1.53, 1.52 and 1.48 (Table 1), but those in Sect. Paeonia are 1.12-1.28 (Table 2-4), 95% confidence limits are 1.46-1.60 for the section Modan and 1.07-1.28 (1.21-1.35 only for PB85078) for the section Paeonia, not overlapping, which indi- cates that the two sections have differentiated in respect of the first pairs of chromosomes.        (3)The population PB85024, which belongs to the P. obovata complex, has a karyotype of 2B (stebbins, 1971), which is a new one in the genus Paeonia. This karyotype is a stable one, for several individuals in the population are uniform in this respect, which shows that Steb- bins’ (1971) generalization that all the species in Paeonia have 2A does not hold true.        (4)  Three populations of P. obovata complex studied in this work from Sichuan and Shaanxi are all tetraploids, and one from Hebei is a diploid.  From the present work and the previcus reports, the materials from Japan and Korea, no matter whether flowers are pink or white, are diploids, those from Heilongjiang Province (with both pink and white flowers) (Liu Ming-yuan, personal communication) and from Heibei Province (with pink flowers) in China are also diploids, the one from Sakhalin (pink flowers) is tetraploid, those from Priamur of the Soviet Union are a tetraploid (with white flowers) and a diploid (with pink flowers), and those from Shaanxi (the Qinling Range) and western Sichuan (with both pink and white flowers) are all tetraploids.  As far as we have now known, ploidy in this parti- cular complex is correlated with the geographical distribution: diploids are found in the cen- tral part, tetraploids occur in the northern limits, and in the south  letraploids are the only cytotype.      (5)  The materials of P. mairei from western Sichuan and Shaanxi (the Qinling Range) are found all to be tetraploids, which shows that two cytotypes, diploid and tetraploid, exist in this  species,  but the geographical distribution pattern of these two cytotypes is to be revealed in the future investigation.     

论盖里森"交易区"理论

关于科学的基本性质和内部结构问题,盖里森在分析和批判逻辑实证主义和反实证主义传统观点的基础上,通过借鉴人类学的研究方法,提出了一种互嵌式的科学结构模式和存在于科学亚文化层面上的“交易区”理论,进而阐述了科学的分立性。盖里森认为,科学是由非统一的多个亚文化以分立的方式构成的,这些亚文化之间存在着“交易区”,不同的亚文化通过联络语言进行交易,并在“交易区”中实现信念和行为的局部性协调,以巩固科学的结构、推动科学的发展。     

重视实验能力培养 提高物理教学效果

通过实验教学提高学生的实验技能是初中物理教学的重要环节，是全面提高学生素质的重要途径．切实提高实验教学效果，提高学生的实验能力是每个物理教师都应重视的课题．