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131.
肺损伤是体外循环心内直视手术的主要并发症之一。肺损伤的机制十分复杂,主要是全身炎性反应和缺血/再灌注损伤所致。肺保护的方法多种多样,其目的是降低全身炎性反应,减轻或避免缺血/再灌注损伤。本文探讨体外循环肺损伤的机制和保护进展。 相似文献
132.
循环肿瘤细胞(circulating tumor cells,CTCs)指自发或因诊疗操作由实体瘤或转移灶释放进入外周血循环的肿瘤细胞。CTCs能被看作液体活检,具有实时监测功能,是一种非侵入性的新型诊断工具,有助于早期发现肿瘤的微转移,可评估预后,在治疗的监测及个体化治疗上具有重要的临床意义。 相似文献
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研究学科领域知识丰富性不同的学生在问题表征过程中信息表征层次的特点。采用“学习-再认”范式,以5类等式为材料,62名初二学生参与实验。结果:两组被试对表面和原理特征一致的等式产生明显的错误再认;对表面特征不一致等式的错误率明显减少。无论原理特征是否一致,两组对表面特征一致等式的反应时无显著差别,但在正确率上丰富组的更高。说明,两组均以有序的系列加工方式编码信息,优先编码表面特征。贫乏组对原理特征的编码干扰表面特征的加工,因而原理特征被丢弃。丰富组加工表面特征则无干扰现象出现,两种特征均能作为再认线索。 相似文献
136.
本文通过对426名在职人员的调查,探讨了变革型领导对工作绩效与满意度的影响机制。最后采用SPSS 13.0和Lisrel 8.7 对数据进行多层级线性回归分析,并依据温忠麟等(2006)的统计步骤分析了有中介的调节作用,得到如下结果:(1)在控制了年龄、性别与任职年限之后,自我效能在变革型领导与工作绩效、工作满意度之间都起部分中介作用;(2)核心工作特征在变革型领导与工作绩效之间起调节作用,调节作用需要通过自我效能作为中介变量。文章最后讨论了本研究的理论和实践意义。 相似文献
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The present study examined the effects of orthographic neighborhood (N) size on the cognitive processes underlying Chinese character reading. Previous research has shown increasing N size facilitates word naming and recognition performance in alphabetic languages. Experiment 1 revealed that a large N size was associated with a general inhibition of processes underlying character reading, in contrast to previous findings with alphabetic languages. This inhibitory effect was influenced by regularity and consistency. Experiment 2 sought to assess the effects of higher-frequency neighbors on character naming performance. The results revealed that higher-frequency neighbors with different pronunciation to the target interfered with the phonological retrieval of targets. We propose that this type of interference may have caused the N size effect observed in Experiment 1. The results of Experiment 3 revealed that a large N size facilitated target naming in the absence of higher-frequency neighbors. The current results shed light on the processes underlying character naming, and we propose possible cognitive mechanisms of the N size effect on Chinese character naming. 相似文献
139.
Jiin‐Huarng Guo Hubert J. Chen Wei‐Ming Luh 《The British journal of mathematical and statistical psychology》2011,64(3):439-461
The allocation of sufficient participants into different experimental groups for various research purposes under given constraints is an important practical problem faced by researchers. We address the problem of sample size determination between two independent groups for unequal and/or unknown variances when both the power and the differential cost are taken into consideration. We apply the well‐known Welch approximate test to derive various sample size allocation ratios by minimizing the total cost or, equivalently, maximizing the statistical power. Two types of hypotheses including superiority/non‐inferiority and equivalence of two means are each considered in the process of sample size planning. A simulation study is carried out and the proposed method is validated in terms of Type I error rate and statistical power. As a result, the simulation study reveals that the proposed sample size formulas are very satisfactory under various variances and sample size allocation ratios. Finally, a flowchart, tables, and figures of several sample size allocations are presented for practical reference. 相似文献
140.
Jiin‐Huarng Guo L. Billard Wei‐Ming Luh 《The British journal of mathematical and statistical psychology》2011,64(2):259-276
When the underlying variances are unknown or/and unequal, using the conventional F test is problematic in the two‐factor hierarchical data structure. Prompted by the approximate test statistics (Welch and Alexander–Govern methods), the authors develop four new heterogeneous test statistics to test factor A and factor B nested within A for the unbalanced fixed‐effect two‐stage nested design under variance heterogeneity. The actual significance levels and statistical power of the test statistics were compared in a simulation study. The results show that the proposed procedures maintain better Type I error rate control and have greater statistical power than those obtained by the conventional F test in various conditions. Therefore, the proposed test statistics are recommended in terms of robustness and easy implementation. 相似文献