Inference for large financial systems

We treat the parameter estimation problem for mean‐field models of large interacting financial systems such as the banking system and a pool of assets held by an institution or backing a security. We develop an asymptotic inference approach that addresses the scale and complexity of such systems. Harnessing the weak convergence results developed for mean‐field financial systems in the literature, we construct an approximate likelihood for large systems. The approximate likelihood has a conditionally Gaussian structure, enabling us to design an efficient numerical method for its evaluation. We provide a representation of the corresponding approximate estimator in terms of a weighted least‐squares estimator, and use it to analyze the large‐system and large‐sample behavior of the estimator. Numerical results for a mean‐field model of systemic financial risk highlight the efficiency and accuracy of our estimator.     

Social media bots and stock markets

This study examines the link between information spread by social media bots and stock trading. Based on a large sample of tweets mentioning 55 companies in the FTSE 100 composites, we find significant relations between bot tweets and stock returns, volatility, and trading volume at both daily and intraday levels. These results are also confirmed by an event study of stock response following abnormal increases in the volume of tweets. The findings are robust to various specifications, including controlling for traditional news channel, alternative measures of volatility, information flows in pretrading hours, and different measures of sentiment.     

民办院校有机化学实验多元化教学模式探索

民办院校把有机化学实验作为有机化学教学的重要组成部分,多元化教学模式主要从教学方法与手段、教学内容、学习方式、考评体系等方面进行多元化教学模式探索。建立以微课视频、翻转课堂、问题引导,依托基础性实验、综合型实验和创新型实验,依托多元化信息化的教学手段雨课堂、虚拟仿真情景模拟实验、超星尔雅平台,融合多种教学方法,结合“线下”翻转课堂,建立多元化教学模式。这种多元化教学模式能有效提高学生的学习主动性和创新能力。     

桑叶配方颗粒物质基准研究

桑叶配方颗粒迄今尚没有统一的质量标准。为提升桑叶配方颗粒的内在质量,对其物质基准评价方法进行了研究。选取具有代表性产地的15批桑叶制备物质基准,采用高效液相色谱法,以芦丁、异槲皮苷、紫云英苷作为评价指标,确定桑叶物质基准的出膏率范围、标志性成分含量及转移率范围,采用超高效液相色谱法,建立物质基准UPLC特征图谱,并对其主要成分进行指认。结果表明:15批物质基准中,芦丁转移率为19.94%～34.05%,异槲皮苷转移率为11.67%～43.58%,紫云英苷转移率为10.73%～43.05%;物质基准特征图谱中,标定了14个共有峰,指认出7个色谱峰,分别为新绿原酸、绿原酸、咖啡酸、芦丁、异槲皮苷、槲皮素-3-O-(6″-O-丙二酰基)-β-D-葡萄糖苷、紫云英苷。所建立的基准评价方法为桑叶配方颗粒质量标准的制定及其后续大规模生产提供了数据基础。     

单矿物及地球化学特征浅析——以内蒙古鄂温克旗头道桥地区糜棱岩为例

头道桥糜棱岩是以塑性变形为主的韧性剪切带,形成了糜棱岩、碎裂岩系列,该糜棱岩带中糜棱岩的原岩均为花岗岩,该韧性剪切带中的糜棱岩化花岗岩、花岗质初糜棱岩以及花岗质糜棱岩的单矿物化学特征和岩石地球化学特征与岩石变形强度增大和退变质作用增强有着密切的关联,他们都表现出了一定的规律性。     

论化学教师的PCK结构及其建构

如何利用学科教学知识提高化学课堂的教学成效,是每一名化学教师都应该关心的问题。     

Learning to bid in sequential Dutch auctions

We propose an agent-based computational model to investigate sequential Dutch auctions with particular emphasis on markets for perishable goods and we take as an example wholesale fish markets. Buyers in these markets sell the fish they purchase on a retail market. The paper provides an original model of boundedly rational behavior for wholesale buyers׳ behavior incorporating learning to improve profits, conjectures as to the bids that will be made and fictitious learning. We analyze the dynamics of the aggregate price under different market conditions in order to explain the emergence of market price patterns such as the well-known declining price paradox and the empirically observed fact that the very last transactions in the day may be at a higher price. The proposed behavioral model provides alternative explanations for market price dynamics to those which depend on standard hypotheses such as diminishing marginal profits. Furthermore, agents learn the option value of having the possibility of bidding in later rounds. When confronted with random buyers, such as occasional participants or new entrants, they learn to bid in the optimal way without being conscious of the strategies of the other buyers. When faced with other buyers who are also learning their behavior still displays some of the characteristics learned in the simpler case even though the problem is not analytically tractable.     

医药学专业有机化学实验教学绿色化改革的探索与实践

报道了对医药学专业有机化学实验进行绿色化改革的措施。通过新实验技术的应用、实验内容的更新、对环境友好试剂和反应的选用、实验的微量和半微量化、实验的重新组合、废物的回收利用等措施的实施,收到了有机实验绿色化的良好效果。     

物理化学课程改革探索与实践

在物理化学课程教学中,笔者针对材料学专业特点,因材施教;结合物理化学特点,适当引入英语教学;结合现实生活,强化物理化学内容的应用;不断吸收现代科学发展的新成果,将学术研究的最新成果转化为教学内容,激发了学生的学习兴趣,培养了学生的逻辑思维能力和创新能力。     

浅谈理工科分析化学实验课程教学改革

本文介绍在分析化学实验教学中,培养学生独立查阅相关文献,设计相关实验,锻炼学生思维能力和动手能力,提高学生分析问题、解决问题的能力,为培养全面型化学化工人才提供有力保障。