松嫩平原北部黑土区水土资源平衡效应研究

研究目的:分析松嫩平原北部黑土区在土地利用和农业气候资源变化条件下的水土资源平衡效应。研究方法:在傅抱璞假设理论的基础上,通过拟合参数ω回归方程求得实际蒸散量,以此来构建水分盈亏模型,分析水土资源平衡效应。研究结果:(1)1985—2015年,松嫩平原北部土地利用表现为湿地面积大幅度减少,水田和旱地面积不断增加;潜在蒸散量和气温具有较为明显的变化趋势,气温以0.27℃/10 a上升,潜在蒸散量以5.15 mm/a下降;(2)经过拟合参数ω方程求得实际蒸散量可以有效反映土地利用状况、地貌特征和土壤属性;(3)1985—2015年间总体的水分亏缺率均值是0.25、0.2、0.31和0.13,而土地利用的影响使严重缺水面积逐年增加,其增加量是总面积的1.59%,约是原有面积的2倍。研究结论:基于傅抱璞理论改进的参数ω能够提高地区实际蒸散量的估算精度,对区域水土平衡评价具有重要意义,为实现区域资源合理利用提供指导。     

Has local informational advantage disappeared?

This study examines how changes in the information environment affect the informational advantage of geographically proximate agents. The long‐term advantage of local agents disappeared at the turn of the millennium. This is accompanied by the reduction in local bias of institutional investors and equity analysts. However, institutional investors continue to trade local stocks disproportionately more often than non‐local stocks; moreover, their local trades outperform non‐local trades in the short term—even for large and liquid stocks. Our results are consistent with improvements in the information environment shortening the horizon of proximity‐based informational advantage.     

阿莫西林克拉维酸钾片含量测定方法的改进

为解决实际应用中克拉维酸钾峰与后相邻杂质的分离度达不到要求的问题,建立了一种同时测定阿莫西林克拉维酸钾片中阿莫西林和克拉维酸钾含量的新方法,采用反相高效液相色谱法(RP-HPLC),Ultimate AQ-C_(18)色谱柱(4.6mm×250 mm,5μm),以pH值为4.4的0.05 mol/L磷酸二氢钠缓冲液为流动相,柱温为35℃,流速为1.0mL/min,检测波长为220nm。结果表明:阿莫西林和克拉维酸钾两主峰与相邻杂质得到完全基线分离,分离度大于1.5;克拉维酸钾对照品溶液质量浓度为0.050 0~0.500 1mg/mL时与峰面积的线性关系良好(r=0.999 8),平均回收率(n=9)为100.14%,RSD值为0.24%;阿莫西林对照品溶液质量浓度为0.100 0~1.000 1mg/mL时与峰面积的线性关系良好(r=0.999 9),平均回收率(n=9)为100.45%,RSD值为0.17%。与原有的《中华人民共和国药典》方法相比,新的阿莫西林克拉维酸钾片含量测定方法专属性好,准确度高,操作简便快捷,结果可靠,可作为一种质量控制方法。     

城市化进程中的乡村衰落现象：成因及治理——“乡村振兴战略”实施视角的分析

党的十九大报告提出了“实施乡村振兴战略”。乡村振兴是“中国梦”不可或缺的组成部分，城市化进程中的乡村衰落现象不容忽视，乡村问题的解决关系到乡村振兴战略能否实现和现代乡村能否建成。为此，剖析了我国乡村衰落的成因，探索了乡村振兴战略落实的办法，提出了现代乡村建设的可能路径。     

The Effect Of Advertising Content Control On Advertising Effectiveness In The Different Forced Exposure Circumstance

With advances in new technology, various formats of online advertising (e.g., in-stream video advertising) often force e-consumers to watch the advertisement during their goal-oriented activities, and this advertising interruption often makes them feel intruded upon and irritated. To reduce such negative reactions toward involuntary advertising exposures, this study examines whether offering e-consumers the option to choose advertising content can influence ad effectiveness in different degrees of forced exposure circumstance. Using a 2 (advertising content control: customization option vs. no option) × 2 (level of forced exposure: pre-rolls vs. rich media banners) factorial experiment, the researcher noted that advertising customization features generate a greater sense of relevance and increased advertising memory, which in turn may lead to more positive attitudes toward the ad regardless of the levels of forced exposure. The findings have theoretical and practical implications on the use of involuntary advertising interruptions in the web interface.     

Non-linear Gaussian sovereign CDS pricing models

Prior literature indicates that quadratic models and the Black–Karasinski model are very promising for CDS pricing. This paper extends these models and the Black [J. Finance 1995, 50, 1371–1376] model for pricing sovereign CDS’s. For all 10 sovereigns in the sample quadratic models best fit CDS spreads in-sample, and a four factor quadratic model can account for the joint effects on CDS spreads of default risk, default loss risk and liquidity risk with no restriction to factors correlation. Liquidity risk appears to affect sovereign CDS spreads. However, quadratic models tend to over-fit some CDS maturities at the expense of other maturities, while the BK model is particularly immune from this tendency. The Black model seems preferable because its out-of-sample performance in the time series dimension is the best.     

Arena-based events and crime: an analysis of hourly robbery data

This article makes use of hourly crime counts to model the relationship between events that take place at the Prudential Center in Newark, NJ and robberies, an arena that has caused local controversy regarding the costs and benefits of hosting such an entertainment venue. Results from the econometric model suggest that the NHL’s New Jersey Devils ice hockey games, concerts, and Disney-themed events are all associated with increases in robbery, while various other event categories such as the NBA basketball games played by the Nets and boxing, and mixed martial arts (MMA) matches are not associated with an increase. These findings support two complementary ecological theories of crime that focus on how events provide additional opportunities for crime by increasing the associated benefits while simultaneously decreasing the cost for economically motivated offenders to take advantage of.     

Effects of pro-growth policies on employment: evidence of regional disparities

The main objective of our research is to study the direct impact of pro-growth economic policies on employment creation globally and regionally, as evidence has countered policy-makers’ expectation that output growth leads automatically to job creation. We innovate by using the ratio of employment to the population above 25 years as dependent variable instead of the customary employment elasticity. We apply generalized methods of moments’ econometrics on dynamic panel data models and find that growth stimulates employment creation on average across 76 countries. The policies promoting private sector credit, investments, openness, services, education spending, tertiary enrollment, and a fixed exchange rate are the ones that create employment. Larger government size undermines job creation, while policies promoting FDI and industrial development fail to stimulate employment. However, we establish that the effect of pro-growth policies on employment varies significantly across regions, with evidence of weaker links between economic policies and employment in Sub-Saharan Africa and the Middle East.     

Brexit and its economic consequences

As the formal process of Brexit has already started, there is much uncertainty about Brexit's impacts on Britain's social, political and economic future. This paper examines the economic impact. After briefly discussing some significant EU treaties that serve as the background materials, it presents the key arguments advocated by the leave and remain camps. The economic impact depends critically on the negotiation outcomes. Aside from the debate on the divorce costs, there are numerous issues that must be negotiated, such as immigration, trade in goods, services, agriculture, fisheries and financial regulations. We discuss various scenarios of possible new trade regimes, resulting in different impacts on the UK economy. With each side having its bargaining chips to play, the trade‐offs between “give and take” in the negotiation game are analysed. Considering various strategic options, this paper urges rationality and cooperation, especially weighing both sides’ entwined economic interests, in addition to their mutual security, defence, environmental and world concerns. The potential gains and losses in the event where the UK contemplates new trade arrangements with the non‐EU countries are analysed in the Appendix .