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黄海丽 《唐山师范学院学报》2010,32(5):66-69
从唐山师范学院花房中采集菘蓝根腐病病根并对其进行了病原菌的分离、纯化和鉴定及不同浓度、不同分子量的壳聚糖对菘蓝根腐病病原菌的室内抑菌作用。结果表明：分离纯化得到致病菌经鉴定为半知菌亚门（Deuteromycotina）、丝孢纲（Hyphomycetes）,丛梗孢目（Stilbellales）、瘤座孢科（Tuborculadales）、镰刀属（Fusarium）真菌。在一定浓度范围内,分子量为3KD、50KD的壳聚糖随着浓度的提高,其抑菌效果也逐渐增强,6mg／ml的效果最好;分子量为150KD时,3mg／ml的效果最好;在一定分子量范围内,除0．75mg／ml的浓度外,随着壳聚糖分子量的提高,其抑菌效果也逐渐增强,分子量150KD的效果最好;本试验中,最大抑菌率为61％。 相似文献
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以菘蓝离体叶片为外植体,研究了激素种类和浓度、接种方式、光照条件等因素对叶片再生的影响,建立了菘蓝离体叶片高频再生体系.结果表明:以MS+6-BA2.0 mg/L+NAA0.2 mg/L+3%蔗糖为培养基,接种后暗培养5天转到光下培养,叶片远轴面向下接触培养基对不定芽的再生最为有效,不定芽不经过愈伤组织阶段直接从叶片上分化产生,再生率高达93.10%.以1/2MS为培养基附加0.1 mg/LNAA可使不定芽生根率达到100%. 相似文献
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《Africa Education Review》2013,10(5):60-69
AbstractHigher education institutions (HEIs) are drivers of social change embedded in a society which is experiencing increasingly complex and multifaceted crises. This is partly attributable to the use of conventional and deterministic problem-solving curricula. A combination of a transdisciplinary approach and indigenous knowledge (IK) as transformative tools in complex systems is critical for pedagogy. This interface embraces the African heritage in Western epistemology putting it on a curricula pedestal which is currently Western-oriented. This article shows how a transdisciplinary approach and IK can transform pedagogies in HEIs through mutual learning and dialogue across disciplines by reflecting on the Life Knowledge Action/Grounding Programme which is a course offered at the University of Fort Hare, South Africa. The article suggests an integration of transdisciplinarity and IK as powerful catalysts for transformation in pedagogical design. 相似文献
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Charles D. Holley Donald F. Dansereau Selby H. Evans Karen W. Collins Larry Brooks David Larson 《Contemporary educational psychology》1981,6(3):227-236
This study examined the utility of intact (i.e., topic outline format) and embedded (i.e., appropriately positioned within the text) headings as processing aids with nonnarrative text. The argument was advanced that headings potentially provide useful cues for both input and output processing but that little empirical evidence exists to either support or refute this proposition. It was further argued that each of the prior studies reviewed were subject to one or more methodological criticisms which may attenuate the generality of the findings. The results of the present study indicated that no advantage accrued to students on the basis of training; however, limitations of this finding are discussed in terms of the amount of training provided and the time available to the students for integrating the new strategies with their existing techniques. The major result of this investigation was that students provided with text containing intact and embedded headings significantly outperformed students whose text did not contain these processing aids. The major benefits were observed at delayed testing; the text-with-headings students recalled approximately 11% more information at immediate testing and 44% more information at delayed testing than the text-without-headings students. Implications of these results and future research issues are discussed. 相似文献
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嘉禾城所在的地方原名禾仓堡。禾仓堡曾经是秦朝戍守五岭军队的屯粮之地,后来发展为湘南地区一座重要军事堡垒。由于开发较早,加上地理条件相对优越,明朝末年禾仓堡已经成为桂阳、临武、蓝山三州县交界地带的一个中心聚落。崇祯年间,刘新宇领导的农民起义促成了嘉禾县的设置,禾仓堡被确定为县署驻地,嘉禾城便是在禾仓堡兴起和发展起来的。 相似文献
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街亭失守的原因历来就有两种说法：一种认为罪在马谡，一种认为是诸葛亮用人不当。其实，街亭之战本来是诸葛亮消灭司马懿的一个天赐良机。但由于诸葛亮没有认识到这一点，这次机会就在他的眼皮底下悄然消失了，因而使他判断失误，指挥不当，致使街亭失守，从而失去了统一中原匡复汉室的机会。 相似文献
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Effects of metacognitive and elaborative activity on cooperative learning and transfer 总被引：1，自引：0，他引：1
Celia O. Larson Donald F. Dansereau Angela M. O'Donnell Velma I. Hythecker Judith G. Lambiotte Thomas R. Rocklin 《Contemporary educational psychology》1985,10(4):342-348
The effects of instructing pairs of students to engage in metacognitive activities (error correcting and key idea detection), elaborative activities (use of imagery, analogies, etc.), or neither during cooperative learning were examined for both initial cooperative learning and transfer to an individual learning task. The results suggest that metacognitive activity facilitates cooperative learning and elaborative activity facilitates transfer to individual learning. These findings have strong implications for the tailoring of cooperative learning strategies to instructional goals. 相似文献
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曾谦 《洛阳师范学院学报》2009,28(6):27-30
位于灵宝附近的函谷关是先秦时期的天险。西汉时期,函谷关东迁至新安县。这次迁移的原因,是因为军队构成的变化,导致函谷关天险地位的动摇、军事价值降低。汉武帝时期,扩大中央集权,加强关中的政治地位的需要,造成函谷关向东迁移。函谷关东迁之后,其军事价值进一步降低。 相似文献
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