Introduction to the Special Forum on Critical Making as Research Program

This special issue spotlights the growing diversity of critical making practices in a range of disciplinary contexts both inside and outside of the academy, and begins to develop perspectives that will foster the emergence of critical making as a coherent field. On one hand, we see great value in incorporating material practices into existing information systems (IS) and science and technology studies (STS) research programs. In particular, forms of material engagement can help overcome the ineffectual linguistic bias of traditional critiques of technoscience. On the other hand, we believe that current material practices can benefit from the conceptualization of knowledge and social organization that are foundational to IS and STS research. In this introduction to the special issue we call attention to the mechanisms by which such practices may combine representational and material work to foster and support the development of new knowledge-making communities and institutions. We believe such work can serve as a framework for others engaged in critical making practices to better contextualize and expand the relevance of their work. We intend this special issue to serve as a “stake in the ground” for research on new forms of material-conceptual critique and their incorporation in the repertoire of critical technoscience scholarship.     

Consensus for multiple heterogeneous Euler–Lagrange systems with time-delay and jointly connected topologies

In this paper, we consider the consensus problem of multiple agents modeled by Euler–Lagrange (EL) equation, among which two classes of agents are addressed, i.e., some agents with exactly known parameters and the others with parametric uncertainties. We propose a distributed consensus protocol for the heterogeneous EL systems in which both time-delay and jointly connected topologies are taken into consideration. Based on graph theory, Lyapunov theory and Barbalat?s lemma, the stability of the controller is proved. A distinctive feature of this work is to investigate the consensus problem of EL systems with heterogeneous dynamics, time-delay and jointly connected topologies in a unified theoretical framework. Simulation results are also provided to illustrate the effectiveness of the obtained results.     

Mean-square exponential stability for a class of discrete-time nonlinear singular Markovian jump systems with time-varying delay

This paper investigates the problem of mean-square exponential stability for a class of discrete-time nonlinear singular Markovian jump systems with time-varying delay. The considered systems are with mode-dependent singular matrices _Er(k)$E_{r\left(k\right)}$. By using the free-weighting matrix method and the Lyapunov functional method, delay-dependent sufficient conditions which guarantee the considered systems to be mean-square exponentially stable are presented. Finally, some numerical examples are employed to demonstrate the effectiveness of the proposed methods.     

Examination of the role of transient receptor potential vanilloid type 4 in endothelial responses to shear forces

Shear stress is the major mechanical force applied on vascular endothelial cells by blood flow, and is a crucial factor in normal vascular physiology and in the development of some vascular pathologies. The exact mechanisms of cellular mechano-transduction in mammalian cells and tissues have not yet been elucidated, but it is known that mechanically sensitive receptors and ion channels play a crucial role. This paper describes the use of a novel and efficient microfluidic device to study mechanically-sensitive receptors and ion channels in vitro, which has three independent channels from which recordings can be made and has a small surface area such that fewer cells are required than for conventional flow chambers. The contoured channels of the device enabled examination of a range of shear stresses in one field of view, which is not possible with parallel plate flow chambers and other previously used devices, where one level of flow-induced shear stress is produced per fixed flow-rate. We exposed bovine aortic endothelial cells to different levels of shear stress, and measured the resulting change in intracellular calcium levels ([Ca²⁺]_i) using the fluorescent calcium sensitive dye Fluo-4AM. Shear stress caused an elevation of [Ca²⁺]_i that was proportional to the level of shear experienced. The response was temperature dependant such that at lower temperatures more shear stress was required to elicit a given level of calcium signal and the magnitude of influx was reduced. We demonstrated that shear stress-induced elevations in [Ca²⁺]_i are largely due to calcium influx through the transient receptor potential vanilloid type 4 ion channel.     

竞技运动视频识别与比较系统的研究

竞技运动视频的识别与比较系统是现代科技训练方法在竞技运动训练中的实现。以定点拍摄的跳远运动视频为研究对象,实现了视频中运动目标分割和提取,进行对运动目标进行合成比较。通过对运动员实际训练体态或动作与标准体态或动作的比较,达到科学的运动分析与诊断的目的。这些功能的实现都是借助于VC++平台在WidowsXP系统下研究和实现的,系统便携、操作简单,有现场实效性。     

单侧功能性踝关节不稳者单腿下落过程的生物力学研究

目的:研究功能性踝关节不稳者患侧与健侧单腿下落生物力学特征的差异性。方法:采用Vicon红外高速摄像系统和Kistler三维测力台对15名单侧功能性踝关节不稳者分别进行患侧与健侧40 cm高的单腿下落实验测试,采集下落过程中触地侧下肢的地面反作用力及运动学数据,用配对t检验分析两侧间的差异性,检验水准选α=0.05。结果:在触地前100 ms时及触地时膝踝的瞬时角度、落地稳定时间、落地稳定末的踝关节角度、膝前馈的角度变化量以及内外侧方向GRF峰值对应时间的比较中,两侧间差异存在统计学意义。结论:单侧FAI者患侧单腿下落触地后各方向地面反作用力峰值相对比健侧单腿下落时小,各方向地面反作用力峰值的出现时间相对晚于健侧;同时还发现单侧FAI者在下落过程中可能存在前馈神经肌肉控制的改变。     

异质型责任主体的环境协同治理效果

政府主导、企业主体、公众参与的“多方联动”中国特色环境治理体系是增强环境主体履行责任、提升生态环境质量、助推经济高质量发展的重要途径。从异质型环境责任主体的内外部协同视角出发,基于2011—2017年中国31个省（区、市）宏观数据及A股1423家工业上市公司相关数据,采用高维固定效应模型探析“多方联动”的环境责任主体“提质”“减排”“增效”的协同治理效果;在环保督查力度持续攀升、环境污染治理行政规制适时调整的背景下,考察环境政策不确定性对于环境责任主体协同治理效果的调节效应。结果表明：①政府规制责任与公众监督责任的内部协同治理发挥显著“提质”效果,倒逼企业积极履行环境治理责任,提升环境责任意识,提高发展质量。②政府规制责任、企业环境责任、公众监督责任“多方联动”的外部协同治理发挥显著“减排”与“增效”作用,不仅降低地区污染排放水平,提高环境治理效率,而且显著提升地区绿色贡献水平,有效促进绿色高质量发展。③环境政策不确定性释放了因时、因地、因事精准施策、适时调整、高效匹配的信号,有效提升了“多方联动”的外部协同治理效果。本文对于加快完善多方协同共治的环境治理机制、推动经济与环境激励相容发展具有重要的现实意义。     

土地规模化经营对农村产业融合发展的影响及作用机制

随着农地流转的深化,土地规模化经营能否促进农村产业融合发展亟待研究。本文基于中国省级面板数据,通过测算农村产业融合发展水平,利用双向固定效应模型和系统广义矩估计方法,实证检验土地规模化经营对农村产业融合发展的影响及其传导机制。进一步基于2020年CLES农户调查数据,利用Logit模型探究了土地规模化经营影响农户参与农村产业融合发展行为的微观基础。研究表明：①从宏观层面来看,土地规模化经营对农村产业融合发展具有推动作用,影响机制分析表明其受到农村劳动力转移和农村居民收入水平的正向调节作用,且是通过提升农村居民收入水平来推动农村产业融合发展。②从微观层面来看,土地规模化经营推动了农户参与农村产业融合发展行为,且是通过提高农户参与农业技术培训积极性来推动农户家庭参与农村产业融合发展行为。因此,推动土地规模化经营与实现农村产业融合发展在政策目标上具有协同性,为实现农村产业融合发展,政府应实施有利于土地规模化经营的配套制度,拓宽农村居民收入渠道,有序推进农村劳动力转移,完善农业技术培训服务,助力农村产业融合发展。     

数学的启蒙--对小学低年级数学学习兴趣培养的思考

本文对小学生低年级数学学习兴趣的问题进行了研究。结合数学的学科特点以及小学生身心发展的规律,对低年级小学生数学教学策略提出了三个建议：（1）创设情境,营造氛围;（2）动手操作,营造氛围;（3）游戏教学,寓教于乐。     

浅析英语专业笔译教学的多媒体网络平台构建

服务于英语专业笔译教学的多媒体网络平台搭建势在必行。本文从建构主义和多元智能学习理论出发,提出了可行的平台搭建模式,使笔译教学成为以课堂为核心的辐射式开放型模式,网络平台在笔译教学中的运用必将有效提高教学效率。同时,平台搭建是开放的,动态的,它与笔译教学相辅相成,相互促进。