What do effective teachers of inner-city children have in common?

This paper investigates the extent to which variables describing the classroom behavior of teachers and variables describing teachers' backgrounds and training explain differences in the effectiveness of teachers in improving the vocabulary skills of inner-city black children in four elementary grade levels. The results indicate that both types of variables explain significant portions of the variation in student achievement. In other words, teachers' choices of techniques matter; and the characteristics of teachers provide some information about their effectiveness. However, the pattern of results indicates that great care must be taken in interpreting individual coefficients. The paper concludes with an interpretation of the results and with suggestions for new directions for research on teaching that follow from this interpretation.     

16层螺旋CT对肝脓肿的临床诊断价值探讨

目的：探讨16层螺旋CT对肝脓肿的临床诊断价值。方法选择40例肝脓肿患者,对其进行16层螺旋CT平扫、门静脉期及动脉期检查。结果患者病灶出现于肝脏左叶12例,肝脏右叶20例,多发8例。病灶呈略低密度影或低密度影,主要为类圆形,3例病灶内部呈现出气体影。结论16层螺旋CT扫描可以有效显示出肝脓肿的病理情况,为临床确诊提供了有效的影像学参考。     

结核性缩窄性心包炎的CT诊断特征

目的探讨胸部X线片无特异征象时CT诊断结核性缩窄性心包炎的特征。方法从4例这种患者的CT图像结合手术进行分析。结果结核性缩窄性心包炎的CT检查心包壁增厚，部分钙化，并有如下特征：壁层心包与心肌图像分离，心影、心包影各时像大小大致不变，增厚心包前侧壁具有特定的弧度。结论CT扫描是诊断结核性缩窄性心包炎的可靠依据。     

CT成像射束硬化校正方法研究

X射线CT(computed tomography)成像技术是现代医学和工业重要的诊断与检测手段。实际使用的射线源一般为宽能谱多色射线源,当多色射线穿过物体时,低能光子由于光电效应被优先吸收,因此使得射线能谱变窄。这导致CT图像的退化和杯状伪影的产生。本文系统分析了CT成像的物理过程,提出了一种简单有效的射束硬化校正方法。此方法包括三步,首先对投影图像进行散射抑制处理,其次是基于重投影的射束硬化校正,最后是基于小波变换的CT图像降噪处理。实验验证了方法的有效性。     

EF-based strategies for productivity improvements at wet-etch stations

Abstract

In complex manufacturing environments, Cycle Time (CT) reductions obtained at critical production steps could generate considerable productivity improvements and lead to capacity increases at no investment costs. A wet-etch station operating in a real semiconductor manufacturing plant has been modelled to investigate the impact of different assignment strategies on CT performance. Assignment strategies based on the “Earliest Finish” (EF) concept have been developed and their productivity efficiency compared with a workload balance-based strategy. The EF-based strategies differ from each other for both computational complexity and amount of real-time information required. Encouraging results obtained for a high detail level EF strategy have inspired the development of conceptually similar strategies characterised by reduced implementation efforts. Fundamental implementation constraints, suggested by the manufacturing engineers familiar with the wet-etch station, have been taken into account throughout the different stages of this study. CT reductions ranging between 11% and 28% could be achieved at the modelled wet-etch station.     

Model-based computed tomography image estimation: partitioning approach

ABSTRACT

There is a growing interest to get a fully MR based radiotherapy. The most important development needed is to obtain improved bone tissue estimation. The existing model-based methods perform poorly on bone tissues. This paper was aimed at obtaining improved bone tissue estimation. Skew-Gaussian mixture model and Gaussian mixture model were proposed to investigate CT image estimation from MR images by partitioning the data into two major tissue types. The performance of the proposed models was evaluated using the leave-one-out cross-validation method on real data. In comparison with the existing model-based approaches, the model-based partitioning approach outperformed in bone tissue estimation, especially in dense bone tissue estimation.     

小儿股骨头缺血性坏死的X线平片与CT对照研究

目的：探讨ＣＴ 在小儿股骨头缺血性坏死（ＬＰＤ） 诊断中的作用和价值－ 材料和方法：回顾性分析５０ 例５８ 髋小儿股骨头缺血性坏死的Ｘ 线平片与ＣＴ 表现,按Ｃａｔｔｅｒａｌｌ 分期标准比较各自的征象－ 结果：ＣＴ在早期病变中可发现较多的征象,包括骺骨化中心微小密度改变、骺软骨的改变和少量关节积液等,对病变的定位和定量更清楚,分期更准确;Ｘ 线平片完全可满足中后期病变诊断和分期要求－ 结论：Ｘ 线平片是ＬＰＤ的首选影像检查方法,ＣＴ在ＬＰＤ 的早期诊断中有帮助,中晚期病变无需ＣＴ扫描     

The effects of conflict,quality, and time on small group information use and behavior in evaluative decision making situations

Graduate students simulated school board members making decisions about educational programs. Situation contexts within the program evaluation reports were varied by conflict (high, low), quality (high, low), and time (long, short). Analyses of Variance (ANOVA) of the qualitative measures m the 2 × 2 × 2 factorial design indicated significant results at the .01 level. The quality of decisions affect support for program continuation. Interactions of conflict and quality affected need for more information and more time in decision making. A conflict and time interaction affected preference to talk to other board members. Changes in situational contexts affected information need and use in small, decision making groups.