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.     

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。     

A new hub and spoke system proposal: A case study for Turkey's aviation industry

In this paper, we are proposing a multi-objective mathematical model for the selection of a newly constructed hub and spoke system. The objectives of this model are maximizing aircraft utilization and revenue whilst reducing the commercially infeasible network detour factor. The sensitivity analysis of the model is tackled using weights related to the objectives as well as the network detour factor. The number of available aircraft and the range that an aircraft can reach are also considered in this model. Since Istanbul has already got a hub and spoke system with busy airports on both sides of the city, the model is applied to three other major cities of Turkey, Ankara, Antalya, and Izmir. The test data consists of over 90 cities in Europe and in the Middle East. The data includes unit passenger revenues and operating costs for the segments, distances between cities and hubs, expected load factors and flying times of segments. The scenarios are tested under specific expectations of airline network experts and the results are visualized by using Pareto front graphs. Compared to other candidates, Antalya stands out as a good choice for a new hub and spoke system in Turkey. The results of this model could be helpful for airlines and other airports in Turkey in order to identify their potential and competitive position in relation to their counterparts.     

城市轨道交通主变电所无功补偿方案研究

分析了城市轨道交通用电负荷的特点及主变电所无功补偿的意义,在现有三种无功补偿方案(电抗器固定补偿、SVC及SVG动态补偿)的基础上,结合轨道交通用电负荷的特点及目前低压配电系统、直流牵引系统新设备的采用,提出了两种新的无功补偿方案。     

基于因子分析法的物流供应商选择模型研究

为了解决在B2C交易实现过程中,由于物流配送供应商的选择不当,而出现配送周期长、费用高、退货退款率增加等问题,本文利用因子分析法探索选择物流配送供应商的合理方法,运用便捷有效的方法帮助电商选择适合自己的物流配送供应商。     

猎头顾问提高人选推荐成功率的路径与技法

近年来,猎头行业在中国本土迅速发展,猎头顾问作为猎头公司的核心资源,在根本意义上决定了猎头公司的可持续发展。本文将围绕猎头顾问如何提高人选推荐成功率的一些路径与方法展开。