On the measurement of comparative advantage

This paper shows that the standard measure of revealed comparative advantage (RCA), ranging from 0 to ∞, has problematic properties. Due to its multiplicative specification, it has a moving mean larger than its expected value of 1, while its distribution strongly depends on the number of countries and industries. These properties make its outcomes incomparable across time and place and its economic interpretation problematic. We propose an alternative measure, the additive RCA, ranging from −1 to +1, with a symmetric distribution that centers on a stable mean of zero, independent of the classifications used. Statistical tests show the distribution of the additive index to be more stable. Besides, we propose an aggregate RCA, a regional specialization index, ranging from 0 for pure intra-industry trade to 1 for pure inter-industry trade. The same conclusions and proposals hold for the multiplicative location quotient (LQ), which is used as a measure for the revealed locational attractiveness of certain regions or countries for certain types of industry.

北京爱育华妇儿医院

北京爱育华妇儿医院是一所符合国家三级医院建设标准、拥有国际一流技术水平的营利性专科医疗机构.医院遵循“以患者及家庭为中心”的服务理念、以“整体医学”为原则的服务模式,面向北京及周边省市乃至全国提供孕期保健、产科、月子服务、儿科、儿童健康管理等全程医疗及健康管理服务.     

Uptake of energy efficiency interventions in English dwellings

Little detailed evidence has previously been available regarding the uptake rate or prevalence of energy efficiency interventions among specific household groups. This study uses the Home Energy Efficiency Database (HEED) to investigate both the combination of measures that have been installed, and in which dwellings, according to key neighbourhood socio-demographic variables, including income and tenure. Analysis of 2000–07 data indicates that approximately 40% (9.3 million) dwellings in England had approximately 23.7 million efficiency measures installed, with an average of 2.5 measures per dwelling. Building fabric-related measures were the most frequent (e.g. cavity wall insulation, loft insulation and glazing) with an average of 2.1 million installed each year. Dwellings with the highest number of fabric interventions (the top 20%) were more likely to be found in areas with low income, with more owner-occupied dwellings, experiencing lower winter temperatures, having a lower proportion of flats, and having a slightly higher proportion of older adults and children. Energy efficiency installations have tended to occur among specific types of households or parts of the building stock. These findings have implications for the design of future government programmes for targeting energy efficiency measures to specific household groups or dwelling types.     

泰康同济(武汉)医院

泰康同济(武汉)医院是泰康保险集团开发新建的第一家医院.本项目坐落于武汉市,服务地区,辐射全国,面向全球.医院将建设成为以"多层次医疗服务"为主体的综合化、多样化、服务型院区,拟包含:为大众服务的综合医疗区、为高端人群服务的国际医疗区、教育培训区、商业配套区等功能设施.泰康同济(武汉)医院是泰康医险结合大健康体系中的关键一步.医院将采用"综合医院+专科中心集群"的模式,建设成为三级综合医院标准的、充满人性光辉的新型医疗机构.     

An ASM/ADM model interface for dynamic plant-wide simulation

Mathematical modelling has proven to be very useful in process design, operation and optimisation. A recent trend in WWTP modelling is to include the different subunits in so-called plant-wide models rather than focusing on parts of the entire process. One example of a typical plant-wide model is the coupling of an upstream activated sludge plant (including primary settler, and secondary clarifier) to an anaerobic digester for sludge digestion. One of the key challenges when coupling these processes has been the definition of an interface between the well accepted activated sludge model (ASM1) and anaerobic digestion model (ADM1). Current characterisation and interface models have key limitations, the most critical of which is the over-use of X_c (or lumped complex) variable as a main input to the ADM1. Over-use of X_c does not allow for variation of degradability, carbon oxidation state or nitrogen content. In addition, achieving a target influent pH through the proper definition of the ionic system can be difficult. In this paper, we define an interface and characterisation model that maps degradable components directly to carbohydrates, proteins and lipids (and their soluble analogues), as well as organic acids, rather than using X_c. While this interface has been designed for use with the Benchmark Simulation Model No. 2 (BSM2), it is widely applicable to ADM1 input characterisation in general. We have demonstrated the model both hypothetically (BSM2), and practically on a full-scale anaerobic digester treating sewage sludge.     

Performance of Buildings under Earthquakes in Barcelona, Spain

Abstract:   The seismic risk of the buildings of Barcelona, Spain, is analyzed by using a method based on the capacity spectrum. The seismic hazard in the area of the city is described by means of the reduced 5% damped elastic response spectrum. Obtaining fragility curves for the most important building types of an urban center requires an important amount of information about the structures and the use of nonlinear structural analysis tools. The information on the buildings of Barcelona was obtained by collecting, arranging, improving, and completing the database of the housing and current buildings. The buildings existing in Barcelona are mainly of two types: unreinforced masonry structures and reinforced concrete buildings with waffled slab floors. In addition, the Arc-View software was used to create a GIS tool for managing the collected information to develop seismic risk scenarios. This study shows that the vulnerability of the buildings is significant and therefore, in spite of the medium to low seismic hazard in the area of the city, the expected seismic risk is considerable.     

Rheological,mechanical, and morphological studies of epoxy/poly(methyl methacrylate) semi‐interpenetrating polymer networks

Semi‐interpenetrating polymer networks (semi‐IPNs) of epoxy resin and poly(methyl methacrylate) (PMMA) were synthesized. Methyl methacrylate (MMA) was polymerized by free radical mechanism with azo‐bis‐isobutyronitrile in the presence of oligomeric epoxy resin (DGEBA), and hexahydrophthalic anhydride as crosslinking agent. The gelation and vitrification transitions during cure/polymerization processes have been examined using parallel‐plates rheological technique. From differential scanning calorimetry and rheological techniques, it was suggested that both curing and polymerization processes occur simultaneously. However, the gelation time was longer for the semi‐IPN than those observed for the cure of pure DGEBA or polymerization of MMA. The gelation time increased significantly when 5% of MMA was employed, suggesting a diluent effect of the monomer. Higher amount of MMA resulted in a decrease of gel time, probably because of the simultaneous polymerization of MMA during the curing process. Structural examination of the semi‐IPNs, using scanning electron microscopy, revealed phase separation in nanoscale size for semi‐IPNs containing PMMA at concentrations up to 15%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Electrochemical Determination of Diffusion Coefficients of Iron (II) Ions in Chloride Melts at 700-750°C

The diffusion coefficients of iron (II) ions depositing on solid tungsten electrodes in a molten chloride systems at about 700°C have been determined by electrochemical techniques. The deposition process occurs under diffusion control for all the iron concentrations and temperatures studied. Conventional cyclic voltammetry and convolution cyclic voltammetry methods were used. Diffusion coefficients of iron (II) were calculated according to Randles-Sevcik and Berzins-Delahay equations for the conventional cyclic voltammetry and also by the limiting convoluted current for the convolution cyclic voltammetry. Convolution cyclic voltammetry is believed to be superior to conventional cyclic voltammetry for the quantitative evaluation of diffusion coefficients. The values of the diffusion coefficients lay in the range 1-40-10⁻⁵ cm²/s for the temperature range of 700-750°C. The Arrhenius temperature dependence of the diffusion coefficients is characterized by the value of E_a = 31.2 kJ/mol.     

塑料泡沫和陶瓷泡沫结构的边长测量表征法

确立了正十二面体为塑料泡沫的单胞结构模型;以边长b为参量推导出模型中各几何量的表达式;对一组给定的b值,计算了几何模型和塑料泡沫单胞尺寸、窗口尺寸的理论值和"真实"值;分析了图像测量结果和计算所得"真实"值间存在的差异及其来源,由此导出模仿计算图像测量值或者把图像测量值转换为"真实"值(反之亦然)的方法, 模仿计算的图像测量值与实际图像测量结果有满意的一致性.边长b是两个相邻节点间的距离,理论上具有唯一性,特别容易确认,不一定需要复杂的设备和专门的技术人员,很少因操作人员识别和选择的任意性或者因图像的"失真"给测量结果带来偏差,计算的结果真实可靠.这种表征方法不仅适用于塑料泡沫,也可用于陶瓷泡沫的表征.     

Postpollination Changes in Floral Odor in Silene latifolia: Adaptive Mechanisms for Seed-Predator Avoidance?

Floral odor is a key trait for pollinator attraction in many plants, but may also direct antagonists like herbivores to flowers. In this study, we examined how floral scent changes after pollination in Silene latifolia, which has a specialized relationship with the seed predator Hadena bicruris. We found an overall decrease in total scent emission and considerable changes in relative amounts of scent compounds after pollination. Lilac aldehydes A and B as well as veratrole contributed most to the decrease in scent emission. These three compounds are known to be key signals for the attraction of H. bicruris to the flowers. A specific downregulation of these compounds may increase the reproductive success of the plant by reducing seed predation after pollination.