Covid-19-tested food labels

While the transmission of virus SARS-CoV-2 via food is rare, some Chinese food retailers are considering a Covid-19-tested food label. However, how consumers may support such a label is unknown. We quantify Chinese consumers’ willingness to pay (WTP) for food carrying a Covid-19-tested label using an online choice experiment. We find that the WTPs for such a label are always positive for all food products considered. The amount of WTP depends on the entities authenticating the labels, country of origin of the food, and consumers’ socio-demographic status. Contrary to expectation, the knowledge on Covid-19 does not affect consumer preferences for the Covid-19-tested food labels. Our benefit and cost analysis suggests a possible large benefit of creating and administering a Covid-19-tested food label. This study provides insights for policymakers, global food manufacturers, and retailers to create marketing strategies to alleviate consumer food safety concerns associated with Covid-19.     

河北省北部山区农村生态环境治理及绩效评价

[目的]农村生态环境是一个复杂的系统,严重的生态环境问题制约着农村经济的发展以及新农村建设,探讨其治理和绩效,有利于解决生态环境建设中的各种问题,对于区域发展具有重要的理论和实践意义。[方法]文章通过构建农村生态环境治理及绩效评价指标体系,采用层次分析法确定各个指标的权重以及灰色关联法分析各指标间的灰色关联度。[结果]河北省北部山区农村生态环境治理绩效评价指标体系要素层中权重值大小依次为生态经济(0. 483 9)、生态环境(0. 273 6)、生态人居(0. 137 1)、生态保护(0. 105 4),说明该地区农村经济水平已达到一定水平,但生态环境、生态保护等仍有待提高。灰色关联法计算结果表明河北省北部山区生态环境中关联系数最高的是畜禽粪便处理率(0. 754),生态经济中关联系数最高的是农民人均纯收入(0. 624),生态保护中关联系数最高的是化肥施用量(0. 846),生态人居中关联系数最高的是饮用水合格率(0. 682),而关联度大小依次为生态保护(0. 724)、生态环境(0. 662)、生态人居(0. 573)、生态经济(0. 543),说明该地区生态环境治理仍有很大空间。[结论]研究结果指出河北省北部山区农村生态环境治理的不足,为进一步完善区域生态环境具有重要的指导意义。     

Interpoint Distance Test of Homogeneity for Multivariate Mixture Models

Finite mixtures offer a rich class of distributions for modelling of a variety of random phenomena in numerous fields of study. Using the sample interpoint distances (IPDs), we propose the IPD‐test statistic for testing the hypothesis of homogeneity of mixture of multivariate power series distribution or multivariate normal distribution. We derive the distribution of the IPDs that are drawn from a finite mixture of the multivariate power series distribution and multivariate normal distribution. Based on the empirical distribution of the IPDs, we construct a bootstrap test of homogeneity for other multivariate finite mixture models. The IPD test is applied to mixture models for matrix‐valued distributions and a test of homogeneity for Wishart mixture is presented. Numerical comparisons show that IPD test has accurate type I errors and is more powerful in most multivariate cases than the expectation–maximization (EM) test and modified likelihood ratio test.     

食品检测实验室质量监督方法探讨

食品检测实验室中最为重要的就是质量监督管理工作,做好质量监督有利于提高实验室工作人员的质检与管理能力,进而推动有关人员的学习进步,以胜任工作岗位,提高该食品检测实验室的质量检测水平,确保检测数据的有效性与无误性。但现阶段我国的实验室由于缺乏统一的行业标准,导致其质量监督工作水平参差不齐,出现了一系列不利于质量检测的因素,比如质量监督目的不明、质量监督内容不完整、质量监督措施不完善等不足,都会影响该实验室对于食品的检测。因此,本文主要就食品检测实验室的质量监督方法进行探究,从各个方面指出质量监督的技术要点。     

刺芪参胶囊的制备工艺研究

目的:探索刺芪参胶囊的制备工艺。方法:采用正交实验,以总皂苷质量为指标,优化提取工艺;采用单因素实验优化制剂工艺。结果:在最佳提取工艺条件下,刺芪参胶囊提取物中的总皂苷含量为12.19 mg·g-1;以糊精作为填充剂、硬脂酸镁为助流剂、95%乙醇为黏合剂制备胶囊剂。结论:刺芪参胶囊的制备工艺稳定可行。     

多视角县级空间开发适宜性评价方法对比研究

［目的］随着市县经济社会发展总体规划的改革创新，越发强调主体功能区制度的完善、强化政府空间管控的能力。空间开发适宜性是合理划分国土空间、优化开发布局的重要基础。［方法］研究通过选取了地形地势、交通干线、人口聚集度、经济发展4项适宜性指标和自然灾害影响、可利用土地资源、可利用水资源、生态系统脆弱性4项约束性指标，建立空间开发适宜性评价指标体系，分别从格网与行政区两种视角出发，开展蒲江县级空间开发适宜性评价，采用点对点匹配度分析对两种评价结果进行综合对比分析。［结果］从总体看，蒲江县最适宜区域占比约为4%，较适宜区域占比约为14%，较不适宜区域占比约为15%，最不适宜区域占比约为67%。行政区视角下，各类开发适宜性等级区域差异明显，但街道、乡（镇）行政区内部具有均质性。具体来说，各类开发适宜性等级区有按行政区集聚的趋势，并且其集聚趋势与多指标评价结果关系密切。空间视角下，各类开发适宜性等级跨行政区，街道、乡（镇）行政区内部具有异质性。一方面，各类开发适宜性等级不受行政区影响，局部精准性更高。另一方面，形成跨行政区的开发时序判读，并且这种开发时序多呈现“中心—外围”结构，便于具体指导区域分步开发。［结论］格网尺度可以更精细地反映县级开发适宜性和开发约束性在空间上的差异化分布，提高城镇、农业、生态3类空间范围划定精准性，为合理确定资源开发强度、促进国土空间科学适度有序布局提供技术保障。     

How to fight against southern pine beetle epidemics: An insurance approach

The southern pine beetle (SPB) is among the leading biological agents killing southern pine species in the eastern United States. In light of recognized spatiotemporal autocorrelation in SPB outbreaks, we devise a spatiotemporal block bootstrapping method that can be applied to analyze spatiotemporally dependent infestations. We also identify the relevant risk determinants and evaluate their impacts on the frequency of SPB outbreaks. For example, we find forest type, climate, and natural disasters like storm and forest management are all significantly associated with SPB risks. Using the results of a statistical model, we design a county-level group index insurance plan that generates estimates of actuarially fair premium rates for timber stands containing southern pine species. Given that no government-provided compensation scheme for SPB epidemics currently exists, application of this new insurance product could reduce forest owners losses. Our study offers an approach to analyzing and protecting against risks of other destructive pests affecting the timber sector.     

The Role of Ethical Standards in the Relationship Between Religious Social Norms and M&A Announcement Returns

Journal of Business Ethics - Prior studies suggest that firms headquartered in areas with strong religious social norms have higher ethical standards. In this study, we examine whether the ethical...     

宏观审慎政策、经济周期与银行风险承担*

本文基于中国227家商业银行2005－2016年非平衡面板数据，实证检验中国宏观审慎政策实施对于银行风险承担的影响。结果表明：宏观审慎政策增强会在一定程度上抑制银行风险承担，而且这种显著的负向关系并不随着银行风险代理变量、经营辐射范围以及是否有外资入股等条件的改变而发生变化。经济周期会对宏观审慎政策的有效性产生非对称性影响，即相比在经济上行时期，在经济下行时期的宏观审慎政策对银行风险承担的抑制作用更强且更为显著。就可能的影响机制而言，本文发现宏观审慎政策通过提高银行盈利能力，从而降低银行风险承担。       

基于混合云架构的交通行业大数据云控平台研究与应用

随着智慧交通的发展,对交通信息化统筹建设、对交通数据的统一管理和深度挖掘应用提出了更高的要求.本文对当前高速公路数据传输、存储、分析应用三个方面进行综合分析研究,设计了基于混合云架构的交通行业大数据云控平台,并对新的融合传输方法、混合云架构数据存储方法和基于中台架构的数据分析应用平台进行了分析.平台对我省智慧交通发展、集团公司数字化的转型有极大的支撑作用.