Systemic Thinking and Practice Toward Facilitating Inclusive Education: Reflections on a Case of Co-Generated Knowledge and Action in South Africa

This article offers our reflections around a case of facilitating systemic thinking and practice in which the first author of the article (Tlale) interacted with research participants/participant researchers with the intention of strengthening systemic thought and action toward fostering inclusive education in the setting (a rural school in the Eastern Cape in South Africa). We reflect upon the process and also how our engagement was perceived by participants, as expressed in feedback received from them. We point to how Tlale introduced the idea of systemic thinking (to teachers, school management team, school governing body, and a district officer for the district) as tied to the possibility of acting to generate transformation toward a more inclusive educational context for the benefit of the learners at the school in question, thus acting as a systemic mediator on their behalf.     

The Ordering and Replacement Policy for the System with Two Types of Failures

In this paper, the optimal maintenance policy is investigated for a system with stochastic lead time and two types of failures. The system has two types of failures, one type is repairable, when the repairable failure occurs, the system will be repaired by repairman, and the system after repair is not "as good as new". The other type of failure is unrepairable, and when the unrepairable failure occurs the system must be replaced by a new and identical one. The spare system for replacement is available only by order, and the lead time for delivering the spare system is stochastic. The successive survival times of the system form a stochastically decreasing geometric process, the consecutive repair times after failures of the system form a renewal process. By using the renewal process theory and geometric process theory, the explicit expression of the long-run average cost per unit time under ordering policy(N-1) is derived, and the corresponding optimal can be found analytically. Finally,the numerical analyses are given.     

Model averaging estimation for conditional volatility models with an application to stock market volatility forecast

This paper is concerned with model averaging estimation for conditional volatility models. Given a set of candidate models with different functional forms, we propose a model averaging estimator and forecast for conditional volatility, and construct the corresponding weight-choosing criterion. Under some regulatory conditions, we show that the weight selected by the criterion asymptotically minimizes the true Kullback–Leibler divergence, which is the distributional approximation error, as well as the Itakura–Saito distance, which is the distance between the true and estimated or forecast conditional volatility. Monte Carlo experiments support our newly proposed method. As for the empirical applications of our method, we investigate a total of nine major stock market indices and make a 1-day-ahead volatility forecast for each data set. Empirical results show that the model averaging forecast achieves the highest accuracy in terms of all types of loss functions in most cases, which captures the movement of the unknown true conditional volatility.     

Forecasting stock volatility in the presence of extreme shocks: Short-term and long-term effects

This paper introduces a novel generalized autoregressive conditional heteroskedasticity–mixed data sampling–extreme shocks (GARCH-MIDAS-ES) model for stock volatility to examine whether the importance of extreme shocks changes in different time ranges. Based on different combinations of the short- and long-term effects caused by extreme events, we extend the standard GARCH-MIDAS model to characterize the different responses of the stock market for short- and long-term horizons, separately or in combination. The unique timespan of nearly 100 years of the Dow Jones Industrial Average (DJIA) daily returns allows us to understand the stock market volatility under extreme shocks from a historical perspective. The in-sample empirical results clearly show that the DJIA stock volatility is best fitted to the GARCH-MIDAS-SLES model by including the short- and long-term impacts of extreme shocks for all forecasting horizons. The out-of-sample results and robustness tests emphasize the significance of decomposing the effect of extreme shocks into short- and long-term effects to improve the accuracy of the DJIA volatility forecasts.     

碱激发矿粉-膨润土竖向阻隔屏障在某风险阻控工程中的应用

以某在产农药厂污染场地风险阻控工程为依托,通过三级搅拌工艺制备屏障材料,并利用高压旋喷注浆法和深层搅拌法施工工艺建造周长659m、深度25m的活性氧化镁激发矿粉-膨润土系竖向阻隔屏障(MSB),实现了MSB材料在国内的工程应用.对施工后屏障进行取样,采用芯样表观特征分析、室内无侧限抗压强度和刚性壁渗透试验分析2种施工工艺、屏障深度和工后时间对屏障无侧限抗压强度qu和渗透系数k的影响.结果表明:2种施工工艺均实现了材料沿深度的均匀搅拌,屏障完整性较好;工后40～70d,qu可达1.6-2.6MPa,qu随工后时间增加呈增长趋势;自来水渗透作用下屏障k为4.5×10-8～9.0×10-8cm/s,k随深度变化不明显.     

装配式地铁车站侧墙-顶板节点抗震性能试验研究

针对装配式地铁车站结构,提出了一种新型的车站顶板与侧墙连接节点.该节点通过车站侧墙顶部伸出的竖向U形钢筋与预制顶板两端伸出的水平U形钢筋搭接连接,从而实现侧墙与顶板间的内力传递.结合实际工程,设计制作了3个U形筋搭接构造形式各不相同的装配式足尺节点试件.通过拟静力试验,研究了节点试件的破坏形态、滞回性能、承载能力、变形性能以及耗能能力.结果表明,装配式节点试件的破坏形态包括U形筋弯弧内侧混凝土的局部受压破坏和侧墙剪切破坏.节点试件的位移延性系数为2.7-3.4,试件顶板端部的极限转角为1/22～1/27.增加节点中受拉钢筋的搭接长度,可以有效确保U形筋搭接连接在往复荷载作用下的有效性.     

A new microfiltration membrane with three-dimensional reticular architecture for Nano-pollutants removal from wastewater

This research provides a new insight into designing next-generation filtration materials for Nano-pollutants removal from wastewater, and potentially for gas/solid or liquid/solid separation in corrosive environment. Considering the high corrosion and oxidation resistance, Ti–40Al–10Nb–10Cr porous alloy was prepared by powder metallurgy and used as a mechanical support with a pore size of around 10 ?μm. Subsequently, metallic Zn nanoparticles was coated on the Ti–40Al–10Nb–10Cr porous framework by means of chemical vapor deposition, obtaining a novel microfiltration membrane with three-dimensional reticular architecture. Furthermore, the influence of Zn coating on surface morphology, pore feature, and filtration capability of Ti–40Al–10Nb–10Cr porous alloy was investigated. It is of note that the as-prepared microfiltration membrane exhibits an excellent Nano-pollutants filtration efficiency of greater than 99.989% from wastewater. Most importantly, such a three-dimensional reticular architecture provides excellent structural stability, allowing the reutilization of the microfiltration membrane for at least 200 filtration cycles of wastewater treatment.     

测试稿件刘蔚霞周磊2 冯利2 张平2*

目的：研究益肾骨康方对骨转移癌疼痛大鼠脊髓背角GFAP、c-fos、P物质蛋白表达的调控作用。方法：在裸鼠肺腺癌溶骨性骨转移模型的基础上,采用免疫组织化学染色的方法,分别观察各组裸鼠脊髓背角GFAP、c-fos、P物质等蛋白的表达。并使用MIA4.0图像分析软件进行图像分析,每张切片取五个视野,显微镜放大倍数为400倍,统计每个高倍镜视野中表达的阳性物质的光密度值。结果：模型组裸鼠发生了100%的骨转移,免疫组织化学结果显示模型组脊髓背角GFAP、c-fos、P物质蛋白过表达；而“益肾骨康方”低剂量组与中 西药组裸鼠未发生骨转移,免疫组织化学结果显示GFAP、c-fos、P物质蛋白的表达处于较低的水平(P<0.01)；“益肾骨康方”中、高剂量组裸鼠也发生了骨转移,但是这两组裸鼠脊髓背角GFAP、c-fos、P物质蛋白等与疼痛相关的蛋白表达明显低于模型组(P<0.05)。结论：“益肾骨康方”可能通过抑制裸鼠脊髓背角GFAP、c-fos、P物质等蛋白的表达,从而抑制肺腺癌细胞的骨侵袭与转移所引起的疼痛,即“益肾骨康方”通过抑制裸鼠脊髓背角GFAP、c-fos、P物质蛋白的表达而起到一定的镇痛作用。     

Triple Medium Physical Model of Post Fracturing High-Rank Coal Reservoir in Southern Qinshui Basin

In this paper, influences on the reservoir permeability, the reservoir architecture and the fluid flow pattern caused by hydraulic fracturing are analyzed. Based on the structure and production fluid f...