基于因子与聚类分析的江苏省邮政业务协同运作实效研究

中国邮政业务出现了发展缓慢、停滞甚至倒退的现象,邮政业务创新成为不可回避的现实问题。通过2013年江苏邮政通信企业统计数据,对江苏13个邮政局的邮政各类业务协同发展水平状况以及资产配置水平进行因子分析和聚类分析。得出江苏省邮政业务地区发展的层次分布情况,分析了业务发展差距的原因,并总结了邮政在协同发展邮政业务的经验。     

Do housing prices promote total factor productivity? Evidence from spatial panel data models in explaining the mediating role of population density

The issue of what to promote in total factor productivity (TFP) in urban areas has been widely discussed in academia and housing prices and population density are confirmed to be two of the most essential driving factors. However, research into the interaction of housing prices and population density with TFP has been neglected, with no previous studies taking spatial factors into consideration, which may bias the results. From this perspective, using spatial panel data models and employing instrumental variables to solve the endogenous problem, this study examines the impact of housing prices on TFP through the mediating effect of population density for 283 Chinese cities during the period 2000–2013, and confirms that the mediating effect accounts for 18.70 % of the total effect. The results show the positive and significant association of housing prices with TFP and the inverted U-shape of population density. The underlying logic is that housing prices change population density by attracting people with high purchasing power and discouraging those unable to afford housing, whereas increased density helps to promote productivity since the settled inhabitants always have highly developed work skills and are well educated. The influencing mechanism of housing prices on TFP through population density is analyzed, namely the spillover effect. We find that the spillover effect exists in the eastern and central regions, as well as first, second, and third tier cities, while for western regions and fifth tier cities, population mobility and increased in housing prices slows their economic development. There is no evidence of any spillover effect in fourth tier cities. A discussion and suggested policy implications are also provided.     

Drivers of research impact: evidence from the top three finance journals

We study the characteristics of all published papers in the top three finance journals (JF, JFE and RFS), and how these paper characteristics affect the number of citations in Google Scholar and the Web of Science database. First, we find the characteristics in the universalist perspective remain constant while the characteristics in the constructivist and presentation perspectives increase over time. Second, some characteristics are significantly different between the high-impact and the low-impact papers. Third, paper quality, research method, journal placement and paper age are the most important drivers. Last, different drivers play different roles in different journals.     

Factors Influencing Organic and Fair Trade Coffee Growers Level of Engagement with Cooperatives: The Case of Coffee Farmers in Mexico

We study the factors influencing the percentage of organic and fair trade certified coffee sold through a cooperative by growers of five cooperatives in Mexico. The percentage of coffee sold through the cooperative was used as a proxy of growers’ engagement with a cooperative. Using factor analysis and a fractional probit regression, we evaluated the proposition that the level of engagement can be explained by transaction cost economics, social norms and connections, and farmer and farm business characteristics. We found that farm size, uncertainty regarding cooperative time of payment to the members and cooperative commitment on price to be paid negatively influence the level of engagement. In contrast, asset specificity, relational commitment, and price have a positive impact on engagement. Our results may help cooperatives and policy makers to build strategies aiming to increase this level of engagement. This is relevant because lower grower engagement has been found to be positively correlated with weak performing cooperatives.     

Minorías étnicas foráneas y determinación salarial en China

Si bien algunos estudios observan que las minorías étnicas urbanas en China perciben salarios más bajos que la mayoría han, otros no constatan la existencia de esa brecha. Para resolver esta contradicción, los autores proponen desglosar las experiencias laborales por grupo étnico minoritario. El análisis de las minorías étnicas sobre un amplio conjunto de datos indica que las «minorías foráneas», como los tibetanos y los grupos túrquicos, sufren una penalización salarial significativa cuando se controlan las covariables, pero no ocurre lo mismo con la totalidad de las minorías. Estas conclusiones son robustas en varias especificaciones y tienen importantes implicaciones teóricas y en materia de políticas.     

凿井水下底卸式自动卸料吊桶

吊桶是立井井筒开凿时期提升矸石和运送材料及升降人员的主要容器,吊桶的卸矸目前多采用挂钩式或座钩式卸料方式;但是随着矿井的开凿深度不断延伸,在过透水层时,由于探放水不及时或涌出水比较大,超出了井筒的排水量,或者是由于冷冻井在解冻后,井筒的井筒质量不过关,各别井壁也会发生透水事故;这就会出现淹井事故,有时淹井深度达二三百米。对于处理这种淹井事故,往往只有一个办法,那就是用沙或混凝土对井筒回填;这就需要吊桶在下到几百米下的水底自动把料卸掉,但现在矿井常用的挂钩式吊桶和座钩式吊桶已经不能满足这个需要了。     

Pairs trading strategies in a cointegration framework: back-tested on CFD and optimized by profit factor

Statistical arbitrage is based on pairs trading of mean-reverting returns. We used cointegration approach and ECM-DCC-GARCH to construct 98 pairs of 152 stocks of 3 currencies. Stocks trading is done by Contract for Difference (CFD), a financial derivative product which facilitates short selling and provides a leverage up to 25 times. To measure the performance of a leveraged strategy, we introduced the profit factor which is the annualized return rate per unit risk. And the historical risk is measured by maximum drawdown. We compared three main strategies: percentage, standard deviation of cointegration long-term residuals and Bollinger Bands (dynamic standard deviation), with and without double confirmation of short-term standard deviation modelled by ECM-DCC-GARCH. Each of the three main strategies is optimized by two optimizers: absolute profit and profit factor. The optimization period goes from 2012–01-01 to 2014–12-31, and validation period is from 2015–01-01 to 2016–06-01. Our results showed that the USD Bollinger Bands strategy without double confirmation and optimized by profit factor, outperformed other strategies and provided the highest annualized return rate per unit risk; 32% of our sample pairs ended up in loss, and 94% of which are explained by a cointegration break during the testing period.     

IMPACT ON FIRMS OF THE USE OF KNOWLEDGE EXTERNAL SOURCES: A SYSTEMATIC REVIEW OF THE LITERATURE

This study summarizes the main conclusions from a systematic review of the empirical literature regarding the impact on firms of the use of knowledge external sources (universities, research institutes and knowledge intensive business services). With the aim to organize the literature, we classify the different works according to the research question addressed: (i) which firms use knowledge external sources?; (ii) Do firms using knowledge external sources achieve better results?; And (iii) which firms benefit the most from using knowledge external sources? Stylized facts are that larger, more R&D intensive and high tech firms are more likely to use knowledge external sources and that use of knowledge external sources is associated to firms higher technical results. Less attention has been paid to the third question and evidence is not conclusive. Several recommendations for future research emerge. First, to take in greater consideration methodological issues so that potential biases in the results caused by sample selection and endogeneity are handled properly. Second, to pay more attention to heterogeneous outcomes. Third, to use continuous indicators of depth and breadth of links allowing for non‐linear relationships and fourth, to extend evidence for developing countries and service industries.     

长沙服务外包产业政策效应实证研究

文章基于长沙市服务外包产业政策,分析服务外包产业政策效应。假设ITO、BPO、KPO三种服务外包类型具有相关性,设立服务外包产业政策效应理论模型。运用SPSS17.0进行因子分析、方差分析和相关分析,测量不同服务外包类型在各种政策影响下所发挥效应是否存在显著差异,以此对长沙市服务外包产业政策效应假设进行验证,并提出服务外包产业政策发展策略。     

英语读写素质研究中的二元理论分析

英语读写素质是习得读写能力并形成读写体验的过程。读写素质主要由分析能力、结合社会文化能力、话语分类能力、读写实践能力、记忆能力、情感反应、思辨能力和隐喻理解能力等因素构成。本文首先应用二元理论中的集对分析理论分析了句子、语法和词语,英语句子具有同异性,英语语法中时态的相关性均有特定的语法表征手段,英语词语是一种约定俗成的语言单位常常附衍了一串同义词、近义词和反义词。如果用联系数来描述词语的相关度,它同时也反映出了词语的思想丰度。本文还运用博弈理论和悖论分析文章的含义及价值,最后应用模糊二元对比排序法对英语读写素质各因素进行分析,通过分析确定了各因素的重要度,将其应用于读写素质研究中具有积极作用并具一定的发展潜力。