Asymptotic limits and stabilization for the 1D nonlinear Mindlin-Timoshenko system

<正> This paper shows how the so called von Karman model can be obtained as a singular limitof a modified Mindlin-Timoshenko system when the modulus of elasticity in shear k tends to infinity,provided a regularizing term through a fourth order dispersive operator is added.Introducing dampingmechanisms,the authors also show that the energy of solutions for this modified Mindlin-Timoshenkosystem decays exponentially,uniformly with respect to the parameter k.As k→∞,the authors obtainthe damped von Karman model with associated energy exponentially decaying to zero as well.     

第一条人类染色体序列正在完成拼接

当人类基因组计划向着在2000年3月前完成人类基因组30亿个碱基的一份草图的目标迈进时,三个测序小组正在到达一个不同的、也许更加有意义的里程碑：第一条人类染色体的完成图谱。在最近两周内,国际22号染色体测序协作组将宣布他们完成这项任务的好消息。与此同时,其他染色体的测序工作也将顺利地在2003年完成其测序的预定目标。参与协作的科学家分别来自：英国剑桥的桑格中心;美国诺曼州极克拉荷马大学;日本东京的庆应大学医学院。科学家们说他们的合作堪称国际学术合作的典范,“许多人为之抛洒了血汗和泪水。”尽管作为国际人类基因…     

System waste in education and research: A Delphi study in India

A concept of system waste has been developed, and reported in the literature, to focus explicitly on waste and its reduction. In this study, which is a part of the authors' ongoing research on system waste, an attempt has been made to estimate current and future system waste in education and research (EDR) in India. The concept of system waste, which is defined as “any unnecessary input to and/or any undesirable output from any system,” is complex, multifaceted, subjective and not generally clearly understood. Its study is a fit case for the use of qualitative group problem-solving techniques. Delphi is the technique which has been used here to learn about system waste. A two-round Delphi study was conducted in 1990 in EDR in which teachers, educational administrators, planners, and parents participated. The paper describes the study and its results.     

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.     

Assessment of the uncertainties in temperature change in China during the last century

We have used the China Homogenized Historic Temperature dataset and some long-term station series of the neighbor countries from CRUTEM3, a 5°×5° gridded dataset of monthly mean temperature since 1900, to provide a 107-year record of surface tem-perature trends and variability. We derived a comprehensive set of uncertainty estimates to accompany the data: measurement and sampling errors, uncertainties in temperature bias estimates, and uncertainties arising from limited observational coverage on large-scale averages have all been estimated. We reanalysed the temperature changes during the period of record. The best estimates of trends for 1900–2006 with uncertainties at 95% confidence range are about 0.09±0.017°C/decade for the year as a whole, and 0.14±0.021°C/decade, 0.11±0.021°C/decade, 0.04±0.017°C/decade, and 0.07±0.017°C/decade for winter, spring, summer and autumn respectively. For 1954–2006, the trends for annual, winter, spring, summer and autumn are: 0.26±0.032°C/decade, 0.35±0.046°C/decade, 0.25±0.051°C/decade, 0.16±0.037°C/decade and 0.22±0.055°C/decade. Winter saw the most significant warming trend in both 1900–2006 and 1954–2006, while during the most recent period (the satellite era, 1979–2006), all the seasons show similar warming trends: 0.45±0.13°C/decade, 0.51±0.11°C/decade, 0.52±0.16°C/decade, 0.37±0.10°C/decade and 0.50±0.16°C/decade for annual, winter, spring, summer and autumn. Trends arising from urbanization have been evaluated as less than 5% of the total warming trend for 1951–2001, so this bias was not removed.