On consistency of linear linearly constrained discrete time systems

This paper addresses the problem of giving consistency conditions for constrained linear discrete time systems in state space form. Conditions for various significant cases are given and analysed. Finally, the structure of the set of initial states for which consistency prevails and the set of reachable states are studied.     

6-磷酸山梨醇脱氢酶基因转化水稻(Oryza sativa L.)研究

以水稻品种秀水11的幼胚为外植体，对影响愈伤组织诱导及植株再生的因素进行了研究。结果表明：MS＋2，4－D 2mg/L作培养基，愈伤组织诱导率达100％，愈伤组织在MS＋6－BA 2mg/L NAA 0.1mg/L的培养基上，分化频率高达75．3％；在此基础上利用基因枪转化技术，将外源的6－磷酸山梨醇脱氢酶基因（gutD)导入水稻基因组，转基因植株表现出对NaCl较强的耐性。     

关于Dedekind和的均值公式

利用Dedekind和的值分布性质,研究Dedekind和的渐近性质,在J.B.Conrey研究的基础上,完善了形如 |S(h,k)|n 的Dedekind和的均值问题的研究     

Effects of Genre and Content Knowledge on Historical Thinking With Academically Diverse High School Students

Historians use a range of genres in presenting their subjects, yet educators have increasingly privileged argumentation to help novices to reason with historical content. However, the influence genre and content knowledge are relatively unmeasured in this discipline. To learn more, the authors asked 101 eleventh-grade students to compose an argument or a summary on the Gulf of Tonkin and analyzed basic and disciplinary reading and writing measures. Results indicate that students with adequate content knowledge performed better on a disciplinary reading measure when composing arguments, and students with limited content knowledge demonstrated greater comprehension when composing summaries. Students with more knowledge wrote more; however, students who wrote summaries were not disadvantaged in terms of level of historical thinking or overall quality. Last, providing students with disabilities with a simple reading accommodation afforded them the ability to participate in the disciplinary literacy task at levels comparable to their peers.     

Installing a System of Performance Standards for National Assessments in the Republic of Trinidad and Tobago: Issues and Challenges

This article explores the challenge of setting performance standards in a non-Western context. The study is centered on standard-setting practice in the national learning assessments of Trinidad and Tobago. Quantitative and qualitative data from annual evaluations between 2005 and 2009 were compiled, analyzed, and deconstructed. In the mixed methods research design, data were integrated under an evaluation framework for validating performance standards. The quantitative data included panelists’ judgments across standard-setting rounds and methods. The qualitative data included both retrospective comments from open-ended surveys and real-time data from reflective diaries. Findings for procedural and internal validity were mixed, but the evidence for external validity suggested that the final outcomes were reasonable and defensible. Nevertheless, the real-time qualitative data from the reflective diaries highlighted several cognitive challenges experienced by panelists that may have impinged on procedural and internal validity. Additional unique hindrances were lack of resources and wide variation in achievement scores. Ensuring a sustainable system of performance standards requires attention to these deficits.     

Weighted Word Pairs for query expansion

This paper proposes a novel query expansion method to improve accuracy of text retrieval systems. Our method makes use of a minimal relevance feedback to expand the initial query with a structured representation composed of weighted pairs of words. Such a structure is obtained from the relevance feedback through a method for pairs of words selection based on the Probabilistic Topic Model. We compared our method with other baseline query expansion schemes and methods. Evaluations performed on TREC-8 demonstrated the effectiveness of the proposed method with respect to the baseline.     

The effect of equipment scaling on children’s sport performance: the case for tennis

The influence of scaling court-size and net height on children’s tennis performance was examined. Sixteen boys (9.7 ± 0.5 years) had to perform a 30-min match in four different conditions, where court-size and/or net height were scaled by using a scaling ratio based on the differences in temporal demands between the children and the adult game. These 30-min matches were analysed using Tennis Analyst (FairPlay Ltd., Jindalee, QLD, Australia) software to determine typical tennis match performance characteristics. Children hit more winners, more forced errors, played more volleys, struck more shots from a comfortable height and played in a more forward court position when the net was scaled. Scaling both the court and net lead to a faster children’s game, more closely approximating what is typical of the adult game. The differences between the typical tennis performance variables recorded suggested that scaling the net led to a more aggressive way of playing. Further, children enjoyed playing on the standard court–scaled net condition more than standard adult conditions. It is suggested that optimising the scaling of net height may be as critical as other task constraints, such as racquet length or court-size, as it leads to a more engaging learning environment for experienced children.     

论陕西省社会资本形态对经济增长的影响

本文基于社会资本理论,分析了陕西社会资本形态及其对经济发展的影响,指出陕西商业文化的不足所导致的生产要素的低效使用是陕西经济增长缓慢的主要原因。     

企业组织结构与分工——由爱立信手机生产外包想到

从管理学和新兴古典经济学的角度，探讨了企业的组织结构随社会分工、进而社会产品交易效率变动的机理，这对于中国企业的管理者如何经营、管理企业有理论和现实指导意义。