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901.
从清末民国的免费师范生制度的具体内容,尤其是有关服务期问题的相关政策,以及这一制度施行的实际效果和存在的问题,有助于更好的完善当今的免费师范教育的角度,主要通过考察清末民国时期的免费师范生制度及存在问题,探讨其为当今免费师范教育留下的极具借鉴意义的经验教训,从而为当今免费师范生制度的改进提出一些建议。 相似文献
902.
The target of rapamycin (TOR) is a central regulator controlling cell growth. TOR is highly conserved from yeast to mammals, and is deregulated in human cancers and diabetes. TOR complex 1 (TORC1) integrates signals from growth factors, cellular energy status, stress, and amino acids to control cell growth, mitochondrial metabolism, and lipid biosynthesis. The mechanisms of growth factors and cellular energy status in regulating TORC1 have been well established, whereas the mechanism by which amino acid induces TORC1 remains largely unknown. Recent studies revealed that Rag GTPases play a central role in the regulation of TORC1 activation in response to amino acids. In this review, we will discuss the recent progress in our understanding of Rag GTPase-regulated TORC1 activation in response to amino acids. Particular focus will be given to the function of Rag GTPases in TORC1 activation and how Rag GTPases are regulated by amino acids. 相似文献
903.
Surface pollen assemblages of human-disturbed vegetation and their relationship with vegetation and climate in Northeast China 总被引:1,自引:0,他引:1
ManYue Li YueCong Li QingHai Xu RuiMing Pang Wei Ding ShengRui Zhang ZhiGuo He 《科学通报(英文版)》2012,57(5):535-547
Pollen assemblages of 53 surface pollen samples from farmlands and wastelands in Northeast China were analyzed. Tree pollen percentages were usually higher than 30%, with Pinus (26.9%), Quercus (0.9%), Betula (0.9%) and Populus (0.7%) as the major types, and herb pollen percentages were usually higher than 50%, with weedy Poaceae (8.7%), Chenopodiaceae (7.1%), Artemisia (1.9%) and Compositae (3.5%) as the major taxa. Thus, the pollen assemblages were consistent with the regional vegetation compositions. However, there were differences in pollen assemblages among regions, especially among different geomorphological units. For example, in the mountains, there were more types of tree pollen and higher total percentages (average 42%) than in other areas, while cereal pollen percentages were lowest (11.2%). In the hills and high plains, herbs made up more than 60% of the pollens, with cereals (average 53.6%) the dominant type. In the low plains, pollen types were similar to those in the hills and high plains, but total pollen concentrations and the proportion of Concentricystes were much higher, while cereal pollen percentages were slightly lower (average 41.6%). Pollen assemblages in different land use types also differed. For example, in farmland, cereal pollen percentages were more than 40% and Chenopodiaceae was usually less than 2.5%, while in wasteland, weedy Poaceae was usually less than 10% and Chenopodiaceae was usually higher than 25%. Total pollen concentrations in farmland (average 3909 grains/g) were much lower than in wasteland (average 15074 grains/g). Redundancy analysis revealed that pollen assemblages were significantly negatively correlated with mean annual temperature (-0.73) and July mean temperature (-0.81) and significantly positively correlated with mean annual precipitation (0.48), indicating that pollen assemblages in the artificial or human-disturbed vegetation reflect regional climate well. Comparison of pollen assemblages in different areas of northern China showed that pollen concentrations reflect the intensities of human impact to some degree. For example, pollen concentrations decrease as human impacts increase in intensity. The cereal pollen proportions in farmland differed by area. In Northeast China, cereal pollen proportions were distinctly higher than in most other areas of northern China, suggesting differences in planting habits and climate. 相似文献
904.
905.
906.
为准确描述与识别时间序列曲线形态,根据曲线段类型定义了5个语素和1个通配符,进而定义语素向量及通配符向量,使得对曲线的描述具有层次性.据此将任意时间序列曲线转变为对应的二维表,二维表第二列组成的字符串能够进行初级的模板匹配,二维表各行所代表的向量增强了语素关系运算的能力,可实现较深入的模式识别.在经典回溯法的启发下设计了一种属性约束下的带通配符字符串匹配算法,并以基于感应线圈信号曲线的车型分类为例,验证了所提出的方法的有效性和合理性. 相似文献
907.
为了解大鼠肝再生中肝细胞、胆管上皮细胞、卵圆细胞、星形细胞、窦内皮细胞、库普弗细胞、陷窝细胞、树突状细胞等8种肝脏细胞的PPARγ信号通路相关基因转录谱及其预示的脂类代谢活动,按本卷2期张丽君[1]等方法分离大鼠再生肝8种细胞,检测它们的PPARγ信号通路基因表达谱,分析其预示的生理活动.结果表明,41个PPARγ信号通路相关基因在大鼠肝再生中发生了有意义的表达变化,其中上调、下调和上/下调的基因为9、9、23个,呈现15种表达相关性.相应细胞的基因数为10、6和1,10、12和2,7、7和0,16、8和3,18、7和1,10、6和1,11、20和0,13、9和4.它们的转录谱预示,胆管上皮细胞和星形细胞的脂肪合成、星形细胞和树突状细胞的胆固醇代谢、8种肝脏细胞的脂肪酸运输和脂肪细胞分化、星形细胞、窦内皮细胞和树突状细胞的脂肪酸氧化和糖异生、胆管上皮细胞和树突状细胞的能量代谢增强.上述结果表明,PPARγ信号通路与大鼠肝再生密切相关. 相似文献
908.
徐助跃 《哈尔滨师范大学自然科学学报》2010,(6):35-37
通过L分解求得L质数集合,于LQ上定义运算得LQ群;并提出具有正反双性的复元体集W,通过约消变换R获得W,在其上建立容消运算U,证明W与LQ群同构而称其为LQR群;最后阐述了它们中反元的实际意义与两群的作用. 相似文献
909.
老子"不尚贤"的人才思想与墨子的"尚贤"观相比,其实质上是一致的,比起墨子,老子的思维显示了更高的道德水准,更加具有哲学思维的深度与智慧。其中所蕴含的辩证法思想与自然、无为、不争等美德,对于当代建设与完善科学合理的人才制度,构建社会主义和谐社会,有着积极的启示意义,值得我们在社会实践中借鉴。 相似文献
910.
通过活性度实验和显微结构分析对国丰钢铁有限公司常用的3种烧结熔剂(生石灰、白云石和石灰石)进行基础性能研究。结果表明,3种熔剂的活性度均不是很好,生石灰熔剂的活性度实测值显著低于其理论值,石灰石熔剂的活性度高于白云石熔剂的活性度;白云石和石灰石熔剂的最佳煅烧温度都在1300℃左右;3种熔剂的杂质含量较多,且分布不均匀,降低了熔剂的有效含量和活性度。 相似文献