Ridge Analysis 25 Years Later

The response surface technique called ridge analysis was originally introduced by Hoerl (1959) more than 25 years ago. Despite tremendous advantages over more conventional response surface procedures when more than two independent variables are present, ridge analysis has received little attention in the statistical literature since then, although numerous applications have appeared in engineering journals. This situation may be partially due to the fact that this procedure led to the discovery of ridge regression, which has completely overshadowed ridge analysis in the literature since. This discussion will briefly review the mathematics of ridge analysis, its literature, practical advantages, and relationship to ridge regression.     

Whole-Plot Exchange Algorithms for Constructing D-Optimal Multistratum Designs

Multistratum experiments contain several different sizes of experimental units. Examples include split-plot, strip-plot designs, and randomized block designs. We propose a strategy for constructing a D-optimal multistratum design by improving a randomly generated design through a sequence of whole-plot exchanges. This approach preserves the design structure and simplifies updates to the information and is applicable to any multistratum design where the largest-sized experimental unit is either a whole plot or a block. Two whole-plot exchange algorithms inspired by the point-exchange strategies of Fedorov (1972 Fedorov , V. V. ( 1972 ). Theory of Optimal Experiments . New York : Academic Press . [Google Scholar]) and Wynn (1972 Wynn , H. P. ( 1972 ). Results in the theory and construction of D-optimum experimental designs . Journal of the Royal Statistical Society Series B Statistics Methodology 34 : 133 – 147 . [Google Scholar]) are described. The application of the algorithms to several design problems is discussed.     

响应面法优化固定化荧光假单胞菌磷脂酶B的研究

以脱胶油磷含量为响应值,采用响应面法和Central-Composite设计对制备固定化荧光假单胞菌磷脂酶B(PfPLB)主要工艺参数(海藻酸钠浓度、壳聚糖浓度和加酶量)进行了优化,并且采用回归分析拟合了三个固定化因子与响应值(磷含量)的回归模型.该模型预测最佳的固定化Pf-PLB条件为:海藻酸钠3%,壳聚糖1.14%,加酶量1000 U/kg.研究固定化Pf-PLB的酶学性质,结果表明其最适反应温度为40℃,比游离酶提高15℃;最适反应pH为5.5,比游离酶降低1个pH单位.固定化Pf-PLB具有较好的酶活稳定性,连续反应6次,其相对活性为初始值的51.6%,显示出良好的应用前景.     

思辨英语视阈下的读者反馈理论综述

英语教学作为各阶段教育的重要组成部分,肩负着深化教学改革,满足新时期国家和社会对人才培养需求的重大任务。学生除了应当具备英语的综合应用能力之外,还应当具有一定的思辨能力。在各教育阶段的英语教学过程中应用Louise Rosenblatt开创的读者反馈理论(reader response theory)教授阅读,可以将教学模式从传统的“以老师为中心”转变为“以学生为中心”,并通过图式理论和反馈日记的辅助作用,逐步培养学生的思辨能力。国内外的教师和研究者应用读者反馈理论进行阅读教学的实践都证明,这一方法能够帮助学生逐步成为独立而有见地的阅读者,进而具有一定的思辨能力。