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关键词： 融券卖空标的   违规   审计师   分析师  

摘要： 从融券卖空作为金融创新的市场交易机制入手,探究其抑制标的公司违规行为的潜在治理效应。基于截至2016年的融券卖空标的名单,采用基于倾向得分匹配的多时点双重差分模型,实证研究发现,融券卖空机制能够抑制标的上市公司的违规行为。采用中介效应模型的检验发现,外部市场的违规监督力量——审计师和分析师,均能够在融券卖空机制抑制标的上市公司违规行为方面发挥中介作用。进一步区分违规行为的类别和程度发现,融券卖空机制对标的公司的信息披露和经营类违规,以及对标的公司不同程度的违规,均具备显著抑制作用。研究结论丰富了融券卖空机制经济后果的理论,也有助于探寻上市公司违规防范的新有效途径,为监管部门进一步加强上市公司违规行为治理与监督提供了新思路。

关键词： 市政基础设施项目   工程总承包   合同价格形式  

摘要： 以市政基础设施项目为研究对象,分析工程总承包模式下合同价格形式的顶层设计,梳理各省市的具体做法,结合合同价格形式的相关规定和工程总承包模式的发包阶段,探讨其工程总承包合同价格形式选择问题,得出宜采取单价合同,尽量不采用总价合同和成本加酬金合同的结论。

关键词： 临床免疫检验质量   检验结果   可靠性   准确性   诊断   治疗  

摘要： 目的分析临床免疫检验质量控制对检验结果可靠性和准确性的作用。方法择取在医院行住院治疗且需行免疫检验的患者130例作为研究对象,时间在2018年1月—2020年1月。按照盲选法分为两组,对照组与观察组各有65例。采取常规质量控制的患者,作为对照组;在常规质量控制之上,加强临床免疫检验质量控制干预的患者,作为观察组。比较检验结果。结果观察组患者免疫检验质量问题发生率、免疫检验结果准确率相较于对照组,差异具有统计学意义(P<0.05)。结论加强临床免疫检验质量控制能够提高检验结果的准确性和可靠性,降低检验质量问题的发生可能,为诊断和治疗提供参考。

关键词： 技能竞赛   医学检验技术   教学改革  

摘要： 医学检验技能竞赛是促进医学检验技术专业学生成才的平台,同时也是检验科教学质量、评价专业教育水平的手段。实践教学是医学检验技术教学的重要内容,通过整合资源、规范教学、完善考核、健全制度等措施,将技能竞赛融合于实践教学活动中,培养学生自主学习和动手操作能力,提高实践教学质量,起到以赛促学、以赛促教、以赛促改、赛教结合、重在教改的作用,促进医学检验技术实践教学的改革。

关键词： Packaged foods   Markers of ultra-processing   Additives   Ultra-Processed ingredients  

摘要： Ultra-processed foods (UPFs) are characterized by the presence of markers of ultra-processing (MUP), either additives (A-MUP) or non-additive ingredients (NA-MUP). The present study aims to characterize the MUP profile of approximately 22,000 UPFs, representative of assortments in French supermarkets. UPFs were ranked according to Siga classification within five UPF technological groups, from C01 to C3, depending on the nature and number of MUPs (MUP1 and MUP2), presence of risk-associated additives, and contents of salt, sugar and/or fat. Then, UPFs were categorized within 10 food categories. The results showed that UPFs contain more NAMUPs than A-MUPs, on average 1.3 more by UPF. The main MUPs are NA-MUPs, i.e., refined oils (52.5 % of UPFs), extracts and natural aromas (42.7 %), synthetic aromas (26.5 %), glucose syrup (20.0 %), native starches (19.1 %), and dextrose (16.2 %). The NA-MUP/UPF and A-MUP/UPF ratios were not correlated in the 10 food categories. Among UPFs, 19 % contained only one MUP, and 31 % contained more than five MUPs. In conclusion, additives are not a sufficient marker of ultra-processing. It is proposed that NA-MUPs in UPFs should be taken into greater consideration and that foods be scored with indices based on the degree of processing, not compositional scores, which fail to filter MUPs.

关键词： Multiplayer social network games   Social interactions   Augmentation and displacement effects   Co-player   Loneliness  

摘要： The academic debate on whether gameplay has a positive or negative effect on players' psychosocial well-being has yet to cease. To resolve this debate, this study focuses on multiplayer social network games (MSNGs), the affordances of which may lead to the coexistence of augmentation and displacement effects. To unpack the conditions under which gameplay has a positive or negative relationship with psychological well-being, this study distinguishes between co-player interaction modes (in-game social interactions vs. social media interactions) and between co-players' identity types (offline friends/acquaintances vs. guild members). An online survey was conducted with 300 gamers in China. The results revealed that more in-game interaction with co-players was positively associated with players' loneliness, whereas more social media interaction with co-players was negatively related to players' loneliness, regardless of the co-players' identities. However, players who played with offline friends/acquaintances did engage in more social interactions than those who played with guild members, especially social media interactions. Moreover, the effect of playing with friends/acquaintances or guild members on players' loneliness was fully mediated by in-game social interactions and social media interactions. That is, the psychosocial influence of gameplay heavily depends on the exact social interactions that players are involved in rather than on general time spent in games, and the augmentation and displacement effects possibly coincide within one game.

关键词： Dynamical systems   Nonlinear oscillators   Conservative systems   Elliptic integrals   Jacobian elliptic functions  

摘要： Closed-form exact solutions for periodic motions of a nonlinear oscillator, which contains a quadratic mixed-parity restoring force, are derived analytically. This oscillator is characterised by two real parameters, which are the coefficients of the linear and the quadratic terms, and has single-well potential. All possible combinations of positive and negative values of these coefficients providing periodic motions are considered, and two families of exact solutions are obtained in terms of Jacobi elliptic functions. The periods are given in terms of the complete elliptic integral of the first kind, the behaviour of these periods as a function of the initial amplitude is analysed, and the exact solutions for certain values of these parameters are plotted.

关键词： breast cancer classification   feature leakage   generalization error   pretrained DCNN   sample size  

摘要： Purpose: Transfer learning is commonly used in deep learning for medical imaging to alleviate the problem of limited available data. In this work, we studied the risk of feature leakage and its dependence on sample size when using pretrained deep convolutional neural network (DCNN) as feature extractor for classification breast masses in mammography. Methods: Feature leakage occurs when the training set is used for feature selection and classifier modeling while the cost function is guided by the validation performance or informed by the test performance. The high-dimensional feature space extracted from pretrained DCNN suffers from the curse of dimensionality;feature subsets that can provide excessively optimistic performance can be found for the validation set or test set if the latter is allowed for unlimited reuse during algorithm development. We designed a simulation study to examine feature leakage when using DCNN as feature extractor for mass classification in mammography. Four thousand five hundred and seventy-seven unique mass lesions were partitioned by patient into three sets: 3222 for training, 508 for validation, and 847 for independent testing. Three pretrained DCNNs, AlexNet, GoogLeNet, and VGG16, were first compared using a training set in fourfold cross validation and one was selected as the feature extractor. To assess generalization errors, the independent test set was sequestered as truly unseen cases. A training set of a range of sizes from 10% to 75% was simulated by random drawing from the available training set in addition to 100% of the training set. Three commonly used feature classifiers, the linear discriminant, the support vector machine, and the random forest were evaluated. A sequential feature selection method was used to find feature subsets that could achieve high classification performance in terms of the area under the receiver operating characteristic curve (AUC) in the validation set. The extent of feature leakage and the impact

关键词： development   infancy   learning   memory   multiple memory systems   object perception   recognition memory   reinforcement learning   reward   visual attention  

摘要： Visual attention both guides and is guided by learning and memory systems. In this article, we use a multiple-memory systems framework to examine the interplay between attention and memory that begins in early postnatal life. We review how attention and memory interact to support infant development with respect to perceptual learning about objects and features, item-in-context spatial memory, and reinforcement and reward learning. We argue that the multiple-memory systems approach offers a useful organizational structure for research on interactions between attention and memory.

关键词： 新形势   食品药品检验机构   政工人员   作用  

摘要： 基于新形势背景下,食品药品检验机构对自身的工作职责展开详细探究,依据各项工作要求对政工人员聘用与管理提出更高要求.同时,也考虑到食品药品检验工作质量关乎大众生命安全与身体健康,要时刻注重自身工作职责与影响性,在人才管理方面加大监管力度,无论是政工人员的专业能力,还是人员的职业素养等,均能保证政工人员重要作用、个人优势等充分性发挥,增强食品药品检验结果可靠性,保证现代化社会和谐发展.