Elasticity of substitution and the stagnation of Italian productivity

The aim of this paper is to investigate the roots of the stagnation in the Italian total factor productivity (TFP). The analysis focuses on the specific pattern of technical progress in determining the dynamics of the TFP. This analysis cannot be done with Cobb-Douglas technology, but requires the employment of a constant elasticity of substitution (CES) production function that allows distinguishing between the direction and the bias of technical progress. We employ a CES specification embodying both labor- and capital-augmenting technical change, with a σ less than 1. We obtain three main results. (1) There seems to have been a structural break around the mid-1990s in the direction and bias of technological change; (2) The first half of the sample features a labor-augmenting technical change and a capital bias; and (3) In the second part of the sample, both these characteristics seem to disappear, and the evolution of factor endowments assumes a key role. This fact may be seen as one of the potential causes of the stagnation in Italian productivity.     

产业结构视角下地方政府竞争对绿色经济效率的影响

在理论机理分析的基础上,基于2004—2016年中国249个地级及以上城市的面板数据,采用系统广义矩估计方法和中介效应模型,实证分析了地方政府竞争对绿色经济效率的影响。结论如下:整体来看,地方政府绝对竞争与相对竞争不仅可以直接抑制绿色经济效率的提升,还会通过引致产业结构的工业化抑制绿色经济效率的提升,就总效应而言,地方政府绝对竞争与相对竞争仍抑制了绿色经济效率的提升,稳健性检验支持以上观点;分地区、城市规模看,东部、中部、西部和中等城市、小城市地方政府绝对竞争与相对竞争均能通过引致产业结构的工业化来抑制绿色经济效率的提升,大城市地方政府绝对竞争与相对竞争未能通过引致产业结构的工业化来抑制绿色经济效率的提升。     

高速铁路综合接地技术

铁路接地技术是人身安全、设备安全的重要保障措施之一。随着我国高速铁路项目建设步伐的加快,以往分散的接地方式已不能适应高速铁路发展的需要。经过对国内外接地技术的研究、消化吸收和试验验证,提出高速铁路综合接地总体技术方案,建立系统标准体系,并确定为装备我国客运专线铁路的重要系统之一,目前已在京津城际,武广、郑西高速铁路及合宁、合武等客运专线广泛应用。     

Co‐evolved genetic programs for stock market trading

The profitability of trading rules evolved by three different optimised genetic programs, namely a single population genetic program (GP), a co‐operative co‐evolved GP, and a competitive co‐evolved GP is compared. Profitability is determined by trading thirteen listed shares on the Johannesburg Stock Exchange (JSE) over a period of April 2003 to June 2008. An empirical study presented here shows that GPs can generate profitable trading rules across a variety of industries and market conditions. The results show that the co‐operative co‐evolved GP generates trading rules perform significantly worse than a single population GP and a competitively co‐evolved GP. The results also show that a competitive co‐evolved GP and the single population GP produce similar trading rules. The profits returned by the evolved trading rules are compared to the profit returned by the buy‐and‐hold trading strategy. The evolved trading rules significantly outperform the buy‐and‐hold strategy when the market trends downwards. No significant difference is identified among the buy‐and‐hold strategy, the competitive co‐evolved GP, and single population GP when the market trends upwards.     

台湾海峡两岸经贸新发展及其贸易机制问题

两岸贸易机制的创新有利于各种类贸易数量与规模的扩大，多出多进，扩大数量，提高贸易层次，而且改变目前低层次、低技术的贸易结构，改变两岸贸易单向、片面、间接、不平衡的不正常状态。2005年是两岸贸易的转折点，两岸贸易关系已经达到了实现突破与质变的临界关口上。两岸农产品贸易有了更进一步的突破与发展，但是，“三通”未通，两岸贸易无法实现双向、全面、直接的正常贸易，贸易内容还是以商品贸易为主。劳务贸易和技术贸易仍然处于起步阶段。虽然“两岸共同市场”无法成型，两岸贸易合作机制问题已经箭在弦上了。     

Climate zone crucial for efficiency of ski lift operators

This paper investigates the efficiency of ski lift companies across different climate zones in a group of countries based on establishment data. By a joint estimation of the stochastic frontier production and efficiency equations, the results indicate that ski areas in subarctic climate zones are far more efficient than their counterparts in warmer zones. The presence of a large local market and elevation of the ski area are factors not relevant for efficiency. Output of ski lift operators (companies) increases with the length of ski runs, number of ski lifts, share of slopes covered by snowmaking facilities and availability of fast lifts. Productivity is also significantly higher for ski lift companies owned by a large conglomerate.     

分析微生物检测技术在食品检验中的应用

本文针对微生物检测技术检测指标、技术特征、必要性等内容展开分析,结合免疫学技术、光谱技术、代谢学技术、分子生物学技术、质谱检测技术、传感器技术在食品检验中的应用要点,目的在于提升食品检验结果可靠性,为技术体系的不断完善奠定基础。     

基于DEA的新疆玉米生产效率地区差异分析

由于经济条件和生产投入的不同,新疆各地州玉米的生产效率存在着一定差异。本文采用数据包络分析(DEA)方法,对新疆2006年9个玉米主产区的技术效率和规模效率进行了测算,并按相对生产效率的大小将9个地州进行了分类。结果显示只有喀什地区和伊犁州DEA是有效的,各玉米产区生产效率的差异主要是投入方面的差异。通过本文,为构建粮食后备产区提供科学的决策依据,并为各地州提出了生产效率的改进方案和对策建议。     

浅谈CAD与标准化

介绍本公司ＣＡＤ软件的标准化进程。     

Embodied Technological Change,Learning‐by‐doing and the Productivity Slowdown*

The productivity slowdown in the US economy since the first oil shock has recently been associated with a larger decline rate of the relative price of equipment investment and a smaller rate of disembodied technical change. We set up a growth model in which learning‐by‐doing is the engine of both embodied and disembodied technological progress. A shift in the relative efficiency of learning‐by‐doing from the consumption to the investment sector is shown to imply a technological reassignment consistent with the above‐mentioned evidence. This result derives from the interaction between the obsolescence costs inherent in embodiment and the learning‐by‐doing engine.