Learning elemental structures and dynamic processes in technological systems: a cognitive framework

An important objective of science and technology education is the development of pupils’ capacity for systems thinking. While in science education the term system relates mainly to structures and phenomena in the natural world, technology education focuses on systems designed to fulfill people’s needs and desires: examples include systems to control the local environment, or the position or motion of objects. Despite the centrality of the system concept to technology and technology education, issues relating to the teaching and learning of systems within the technology curriculum have been little addressed. This paper explores some elemental structures common to technological feedback control systems, and highlights the relationships between the structural nature and the dynamic behavior of these systems. It is argued that the study of systems and control concepts in technology has the potential to promote higher learning skills such as interdisciplinary thinking and modeling, and an instructional framework for achieving this goal is proposed. Questions and research issues on the fostering of systems thinking in technology education are identified.     

气候变化认知对农户适应性耕作行为的影响基于湖北省“十县千户”的田野调查

[目的]气候变化适应是发展"气候智慧型农业"的重要内涵,是实现国家粮食安全和可持续发展的根本途径之一。[方法]文章通过构建农户"气候变化认知—适应性行为"决策分析框架,并利用湖北省"十县百组千户"的调查数据与结构方程模型,以探究农户气候变化认知(自然环境认知、经济需求认知、自我效能认知)对其(主动型、被动型)适应性耕作行为的影响。[结果](1)农户气候变化认知水平提高能促进其采取适应性耕作行为;其中,气候变化认知水平提高促进其采取主动型适应性耕作行为的作用更大。(2)从影响路径来看,自然环境认知、自我效能认知通过影响情感态度、问题应对策略,经济需求认知通过影响情感态度,以促进农户采取适应性耕作行为。(3)多群组分析还发现,受教育程度越高、家庭农业收入占比越大、种植规模越大的农户,其气候变化认知水平越高,则越倾向于采取主动型适应性耕作行为。[结论]政府应及时发布气候变化的新闻资讯、加大气候变化知识的宣传教育力度、加强适应性耕作技术的相关培训、完善农业气象指数保险,以强化农户自然环境认知、提高经济需求认知和自我效能认知,进而引导其采取适应性耕作行为。     

Diminished-dimensional political economy

Economists base policy advice on models of responses by a variety of economic entities to policy adoptions. There is compelling evidence that these entities do not optimize as mainstream economics assumes. Rather, they limit decision-making to solving problems of much smaller dimensionality. We consider how political economy goes awry when ignoring diminished dimensionality, and some research avenues opened up by this realization.     

Substitution between water and other agricultural inputs: Implications for water conservation in a River Basin context

Substitution of irrigation water with other agricultural inputs could be an important means to conserve water in the face of growing pressures on water resources from both nonagricultural water demands and environmental water requirements. This paper discusses the potential of such substitution through an empirical analysis based on a multiple-input crop production function at the field and farm scales complemented with a numerical modeling exercise at the basin scale. Results from the crop production function analysis show that under both crop yield and net profit maximization, water is a substitute to other crop inputs for high-value crops, and is a complement to water for low-valued crops. At the basin scale, an integrated economic-hydrologic river basin model is used to analyze the role of other factors in crop input substitution, including the spatial connections among water sources and demands, hydro-agronomic conditions, and institutional settings for water allocation. Results show that in the case study area, the Maipo River basin in Chile, where water is very scarce, moving from the current, input-constrained, situation to full optimization of water resources leads to an increase in all crop inputs, including water. In that case, 301 million m³ of additional water use results in additional net profits of USD 11 million. However, if the water fee is raised by a factor of eight while overall basin irrigation profits are maintained at the original, baseline level, a reduction of water withdrawals by 326 million m³ is traded off with costs of USD 43.2 million for other inputs. Irrigation districts with a high share of low-value crops have a low potential for substituting water with other crop inputs. Therefore, investments for water substitution should also be kept low in these areas.     

转型期知识产权保护制度的增长效应研究

知识产权保护制度是发展中国家能否克服短期技术困境、促进经济长期增长的关键因素。本文从宏观层面研究我国知识产权保护制度对经济增长的影响机制,主要贡献在于:首先通过构建知识产权保护指数,实际测算1985—2010年中国的知识产权保护程度。其次通过构建"知识—生产"两部门理论模型,分析知识产权对经济增长的影响机制。最后基于中国转型期经验数据,运用动态建模方法实证研究我国知识产权制度对经济增长的影响。研究表明,对于处于转型期的中国而言,短期内较弱的知识产权保护程度有利于经济增长,而较强的知识产权保护程度则有碍于经济增长;在长期均衡的状态下,较强的知识产权保护程度确实可以促进经济增长。     

供应链建模方法研究综述

通过整理和分析,将当今主要的供应链建模方法归为四类:图形化建模方法、数学建模方法、基于语法的建模方法以及仿真建模方法。在对这四类供应链建模方法进行比较和分析后,提出基于语法的建模方法独具优势,是以后供应链流程建模方法的发展趋势。     

The globalization of operations in Eastern and Western countries: Unpacking the relationship between national and organizational culture and its impact on manufacturing performance

Understanding national and organizational culture becomes increasingly important in the era of transnational manufacturing. As the world becomes flat and boundaries break down, manufacturers need to understand the proper role of culture in order to obtain competitive advantage. Thus, the current study conducts a multilevel investigation of the impact of eight national and organizational culture dimensions (according to GLOBE framework) on manufacturing performance. An ANOVA comparison of 189 manufacturing plants between Eastern (Japan and South Korea) and Western (Germany, United States, Finland, and Sweden) countries indicates that organizational culture inside plants differs in three dimensions (power distance, future orientation, and performance orientation). Hierarchical Linear Modeling analysis further suggests that organizational culture has more of an effect on manufacturing performance than national culture or the fit between them. In addition, Country Developmental Indexes, both Economic and Infrastructural, do not impact manufacturing performance, reinforcing our conclusion about the weak influence of the national level factors on manufacturing performance. In an era of globalization, these results have practical implications for organizations expanding across national boundaries by developing an internal organizational culture consistent with high performance manufacturing.     

Does decrease in copying cost support copyright term extension?

Copyright duration has been or is being extended in many countries. Technological and demographical changes were cited by a US Senate report to argue for US copyright term extension. This paper analyzes the validity of the arguments. Simulation of a model of the information product market indicates that a decrease in copying cost of information products due to digital technologies calls for a reduction of copyright duration. Partial support is found for the argument that longer life expectancy and delayed child-bearing may support copyright term extension. Furthermore, an increase in demand for information products is found to call for reduction in copyright duration.     

OVERCOMING SPREADSHEET RISK IN SUPPLY CHAIN MODELING

Spreadsheet optimization modeling plays an important role in the management of today's sophisticated supply chains. However, despite the advantages of spreadsheets (or in some cases because of these advantages) there are significant risks associated with spreadsheet models. Spreadsheet risk is defined as the chance of adverse operational or financial consequences due to erroneous creation, maintenance, and/or use of spreadsheet models. Such errors arise because the intrinsic complexity of optimization models is beyond the expertise of many non‐technical managers. In this article we discuss procedures that we developed for managing the substantial risks associated with the use of spreadsheets for supply chain optimization. The issues we address go far beyond simple data entry mistakes, which are possible in virtually every aspect of business and can never be completely eliminated.     

Long-term cost-consequence analysis of exenatide once weekly vs sitagliptin or pioglitazone for the treatment of type 2 diabetes patients in the United States

Abstract

Objective:

Exenatide once-weekly (ExQW) is a GLP-1 receptor agonist shown to lower glucose and cardiovascular risk factors in patients with type 2 diabetes mellitus (T2DM). The objective of this study was to estimate the clinical benefits and associated economic benefits of treatment with ExQW compared with sitagliptin or pioglitazone in the US.

Methods:

The IMS CORE Diabetes Model, a validated computer simulation model, was used to project lifetime clinical outcomes and complication costs. The costs of glucose-lowering drugs were excluded as not all prices were available. Baseline patient characteristics (mean values: age, 52.5 years; diabetes duration, 6 years; HbA1_c, 8.51%; body mass index, 32.12?kg/m²) and clinical data were derived from a phase 3 clinical trial that compared ExQW with sitagliptin or pioglitazone in T2DM patients. At 6 months, patients treated with ExQW had greater improvements in HbA1_c and body weight than those treated with sitagliptin or pioglitazone. Complication costs were extracted from published sources. Health outcomes and costs were discounted at 3% per year. Sensitivity analyses were performed.

Results:

Over 35 years, and compared with sitagliptin or pioglitazone, ExQW increased life expectancy by, respectively, 0.28 (13.76?±?0.17 vs 13.48?±?0.18) and 0.17 years (13.76?±?0.17 vs 13.59?±?0.17), and quality-adjusted life years by, respectively, 0.28 (9.56?±?0.12 vs 9.28?±?0.12) and 0.24 years (9.56?±?0.12 vs 9.32?±?0.12). ExQW was associated with lower lifetime complication costs: compared with sitagliptin or pioglitazone, ExQW saved, respectively US$2215 (US$55,647?±?2039 vs US$57,862?±?2159) and US$933 (US$55,647?±?2039 vs US$56,580?±?2007) direct cost per patient. Cost-savings resulted mainly from a lower projected cumulative incidence of cardiovascular diseases and neuropathic complications.

Limitations:

Short-term changes in surrogate end-points were used to project lifetime effects on clinical outcomes. Pharmacy costs were excluded from the analyses.

Conclusions:

Over a patient’s lifetime, ExQW was projected to improve health and decrease diabetes-related complication costs compared with sitagliptin or pioglitazone.