保定市主要作物需水量和缺水量特征分析

[目的]对作物需水量及缺水量的研究是了解和合理配置农业灌溉用水的基础,对提高农业用水效率有重大意义。[方法]选取河北省保定市为研究区域,利用Penman-Monteith公式和分段单值平均作物系数法对冬小麦、夏玉米和棉花的作物需水量和缺水量等指标进行计算,通过Mann-Kendall检验法对保定市近60年来的作物需水量和缺水量等的变化趋势进行分析。[结果]3种主要作物的需水量、有效降雨量和缺水量的最大值均出现在作物发育中期;其中除冬小麦的有效降雨量以0.208mm/10年的速率呈不显著性增长趋势外,其他作物的各指标变化则均呈减少趋势;从突变现象来看,夏玉米和棉花的各指标发生明显变化的时期相近,需水量出现明显拐点的时刻在2008年以后,有效降水量在1968年以前和2014年两个时期,缺水量分别在2011年和2012年。[结论]该研究结果为保定市乃至河北省的农作物灌溉效率的提高及水资源规划与管理的完善提供了理论依据,具有一定的现实意义。     

Box-Behnken响应面法优化徐长卿配方颗粒挥发油-β-CD包合物制备工艺

为了解决徐长卿挥发油加油难及加入后的稳定性问题,采用Box-Behnken响应面法,优选出徐长卿配方颗粒挥发油-β-CD包合物的制备工艺。在单因素试验的基础上,采用3因素3水平Box-Behnken设计对徐长卿配方颗粒挥发油-β-CD包合工艺进行优选,以挥发油包合率及包合物收率为考察指标,考察挥发油与β-CD比例、包合温度、包合时间对结果的影响。结果表明:优选的包合工艺条件为挥发油与β-CD质量比为1∶8.34,包合温度为50.2℃,包合时间为2.17 h。在此条件下,挥发油包合率为72.19%,包合物收率为75.06%,综合评分为96.41,RSD值为1.1%。优选的包合工艺包合率高,工艺稳定可行,可为配方颗粒挥发油的工业化生产提供数据支持。     

基于遥感蒸散数据的农田灌溉水平评价和设施建设分区研究

[目的]利用遥感蒸散数据快速评价农田年度灌溉水平,及时获取基本农田建设成效,为农田灌溉设施分区建设提供参考。[方法]以黑龙江省海伦市为研究区,MOD16蒸散产品为数据源,计算有效灌溉量、灌溉需水量和作物缺水指数,分别对研究区2013年的旱地和水田灌溉水平进行评价,并将评价结果与农田水利设施作用分值图进行叠加分析,在此基础上进行基本农田灌溉设施建设分区。[结果]2013年海伦市耕地灌溉水平整体较高,区域间建设水平差别较大,可划分为4个级别。其中1级和2级灌溉水平的地块面积比例可达78.06%,地域分布上看,北部、西部、中部乡镇灌溉水平较高,东南部乡镇灌溉水平相对较低。叠加得出8种组合类型,分为设施修建型、设施提升型和设施维护型3种分区类型。[结论]研究为高标准农田建设提供了更详细的农田灌溉水平评价方法和更具差别化的农田灌溉设施建设策略。     

The Effects of Search-Related and Purchase-Related Mobile App Additions on Retailers’ Shareholder Wealth: The Roles of Firm Size,Product Category,and Customer Segment

Mobile channel additions have been shown to increase consumer-brand relationships, brand satisfaction towards and overall purchasing from a retailer, but what is less apparent is whether shareholders are fully rewarded for retailers’ mobile channel additions. Results from an event study on 115 announcements relating to mobile app additions of publicly traded U.S. retail firms between 2009 and 2016 indicate that the stock market responds generally positively to mobile app additions, but specifically to the two mobile app addition types. Stock market responses to search-related and purchase-related app additions are moderated by firm size, product category, and target customer age. For announcements of search-related apps, the market responds more positively to product retailers than to service retailers, and to small firms than large ones. For announcements of purchase-related apps, the market responds less positively to firms that target younger customers than firms who do not especially target them.     

Sensitive Survey Questions: Measuring Attitudes Regarding Female Genital Cutting Through a List Experiment

Potential bias in survey responses is higher if sensitive outcomes are measured. This study analyses attitudes towards female genital cutting (FGC) in Ethiopia. A list experiment is designed to elicit truthful answers about FGC support and compares these outcomes with the answers given to a direct question. Our results confirm that the average bias is substantial as answers to direct questions underestimate the FGC support by about 10 percentage points. Moreover, our results provide suggestive but not statistically significant evidence that this bias is more pronounced among uneducated women and women targeted by an NGO intervention (not randomly assigned).     

How much does tax erode fund excess returns?

We model the tax drag from active fund management based on reported monthly holdings of active equity funds. Tax drag erodes 65 percent of the 0.74 percent excess return in Broad Market funds, but only 21 percent of the 1.80 percent excess return in Small-Cap funds for Australian superannuation (pension) fund investors. Tax drag varies with investment style; market state, which is most detrimental during bull markets; and fund turnover. For high-income individual investors, tax drag is exacerbated to the extent that active management only generates meaningful after-tax excess return for Small-Cap funds of certain styles.     

大学生知识付费平台使用满意度分析

随着移动终端的普及和知识付费产业的市场竞争加剧,知识消费者对知识的付费意愿和观念开始转变,许多用户对信息的选择行为理性化和成熟化趋势更加明显,知识付费平台行业发展也进入瓶颈期,为了高效实现客户裂变与流量变现,必须深入研究用户需求.文章以满意度评价这一角度,基于对SERVQUAL模型修正后的二级指标,分析高校学生这一特定的用户群体对知识付费平台的需求,并得出结论,为知识付费平台从法律、平台、产品、市场角度提出了具体建议,期望能对知识付费平台的未来发展起到一定作用.     

Assessing models of individual equity option prices

Review of Quantitative Finance and Accounting - This study sheds light on risk exposures of cooperative banks in Austria, Germany and Italy. We investigate how major risk elements of banks in these...     

新形势下加快推进河北省民营经济高质量发展的路径选择--基于俄罗斯中小企业发展的得失分析

当前,大众创业、万众创新已是时代最强音,论文通过对俄罗斯政府推进中小企业发展相关做法的得失进行评析,提出河北发展民营经济的路径和方法,力求为河北省民营企业高质量发展提供有益借鉴。     

Does Monetary Policy Respond to Uncertainty? Evidence from Australia

We construct a novel measure of uncertainty using expert monetary policy recommendation data for Australia. Our results suggest that the Reserve Bank of Australia (RBA) tends to lower the cash rate when expert uncertainty is high. This result is robust to using other uncertainty measures.