零工经济时代数字平台控制劳动力的供给行为

本文首先基于委托-代理模型构建了一个数字平台控制劳动力供给的行为经济学模型,从理论上分析了数字平台控制劳动的方式和心理机制;然后建立了一个赫克曼(Heckman)选择模型,利用Uber的大数据实证分析了网约车司机的劳动决策.研究结果表明:(1)在零工具有参考点偏好的前提下,数字平台通过高货币激励或高目标奖励使零工劳动者的参考点具有适应性,进而避免其过早地陷入“收入目标”行为;(2)数字平台利用零工劳动者的厌恶损失偏好,对其实施控制以延长工作时间;(3)网约车司机存在“收入目标”行为,且该行为呈现出动态性的特点;(4)收入激励和“峰时”溢价对网约车司机的工作概率和工作时间具有显著的正影响,且在一天的某个时间段内能够抑制网约车司机的“收入目标”行为.可见,零工经济时代到来,一方面提高了劳动力资源配置效率;另一方面,数字平台通过劳动控制变相延长了零工的劳动时间,加剧了剥削.     

加强政策事中事后评估的思考

党的十九届四中全会明确提出要强化决策执行、评估、监督,做好政策评估对优化政府职能、推动国家治理体系和能力现代化有积极作用。加强政策运行情况的评估,应从优化评估工作机制、完善和培育评估机构、强化评估结果的应用入手,不断提升评估工作质量,形成适应中国特色社会主义现代化治理体系的事中事后政策评估机制。     

微波提取酵母胞内甘油的分析方法初探

本文探讨了面包酵母胞内甘油分析的预处理方法——微波破碎法。通过单因素实验分析,确定了胞内甘油的提取条件:酵母细胞用微波破碎3次、每次破碎10 s、间隔5 s,然后用10 mL蒸馏水提取30 min得到胞内甘油,此法简便、易提取,适用于天然产物的快速提取。     

绿色环保军用食品的研究与进展

军用野战食品是保证战士饮食的重要食物,对提高战士的身体素质、提升军队的战斗力具有至关重要的作用。各国军队首脑对此都十分重视,将此项内容作为军队建设的重要内容。基于此,本文综述了相关学者对军用食品的研究,以期为相关学者提供借鉴。     

Adoption of farm‐based irrigation water‐saving techniques in the Guanzhong Plain,China

This article analyses adoption of farm‐based irrigation water saving techniques, based on a cross‐sectional data set of 357 farmers in the Guanzhong Plain, China. Approximately 83% of the farmers use at least one farm‐based water‐saving technique. However, the traditional, inefficient techniques border and furrow irrigation are still prevalent whereas the use of advanced, more efficient techniques is still rather rare. We develop and estimate an adoption model consisting of two stages: awareness of water scarcity and intensity of adoption. We find that awareness of water scarcity and financial status enhance adoption of more advanced techniques whereas access to better community‐based irrigation infrastructure discourages it. We furthermore find both community‐based irrigation infrastructure and farm‐based irrigation water‐saving techniques have mitigating effects on production risk. From the results it follows that adoption can be stimulated via financial support and via extension aimed at enhancing awareness of water scarcity.     

Latent vs. Observed Variables: Analysis of Irrigation Water Efficiency Using SEM and SUR

In this paper we compare conceptualising single factor technical and allocative efficiency as indicators of a single latent variable, or as separate observed variables. In the former case, the impacts on both efficiency types are analysed by means of structural equation modeling (SEM), in the latter by seemingly unrelated regression (SUR). We compare estimation results of the two approaches based on a dataset on single factor irrigation water use efficiency obtained from a survey of 360 farmers in the Guanzhong Plain, China. The main methodological findings are that SEM allows identification of the most important dimension of irrigation water efficiency (technical efficiency) via comparison of their factor scores and reliability. Moreover, it reduces multicollinearity and attenuation bias. It thus is preferable to SUR. The SEM estimates show that perception of water scarcity is the most important positive determinant of both types of efficiency, followed by irrigation infrastructure, income and water price. Furthermore, there is a strong negative reverse effect from efficiency on perception.     

Value of hedge and expected returns

We demonstrate how it is possible to generate value for an investor with a hedge attached to the buy-and-hold strategy of an S&P 500 index fund. We study the S&P 500 index portfolio (not including dividends) and the value-weighted S&P 500 index portfolio (including dividends) of the Center for Research in Securities Prices for 1967:01–2011:12, using the capacity utilization and the unemployment rates in real time to determine if a hedge position should be initiated or closed. A hedge is initiated if the capacity utilization, the unemployment rate or a combination of the two signals a contraction in the real economy. The hedge position is closed if it signals otherwise an expansion. We use utility gains (Campbell and Thompson 2008), the manipulation-proof performance measure (MPPM) statistics (Ingersoll et al. 2007) and the P-Sharpe ratio (Bailey and López de Prado 2012) to evaluate the performance of a particular hedge strategy. The empirical results show that there are infinitely many hedges that can generate positive utility gains, higher MPPM statistics and higher P-Sharpe ratios.     

人力资源管理强度的研究回顾及在中国情境下的理论框架建构

人力资源管理强度能够从整体上反映企业人力资源管理的效果,在组织管理实践中具有重要的指导作用.但以往关于人力资源管理强度的探讨主要集中于西方情境,这极大地限制了其在中国情境下的发展.因此,本文立足于中国情境,在对现有人力资源管理强度进行理论回顾的基础上,构建了中国情境下人力资源管理强度的研究框架,并从维度、测量与实证研究三个方面进行了未来展望.     

洪口水电站坝基工程地质研究

通过对洪口水电站坝基工程地质条件分析,根据流纹岩岩体硬、脆、碎的特点和物理力学特性,进行工程地质研究,充分利用弱风化流纹岩作为大坝基础,对坝基稳定分析计算,提高了建基面,提出合理处理方式,减少工程量和节省工程投资。