No experience required: Violent crime and anticipated,vicarious, and experienced racial discrimination

There is a growing body of evidence linking racial discrimination and juvenile crime, and a number of theories explain this relationship. In this study, we draw on one popular approach, Agnew's general strain theory, and extend prior research by moving from a focus on experienced discrimination to consider two other forms, anticipated and vicarious discrimination. Using data on black, white, and Hispanic youth, from the Project on Human Development in Chicago Neighborhoods (PHDCN), we find that experienced, anticipated, and to a lesser extent, vicarious discrimination, significantly predict violent crime independent of a set of neighborhood, parental, and individual level controls, including prior violent offending. Additional analyses on the specific contexts of discrimination reveal that violence is associated with the anticipation of police discrimination. The effects tend to be larger for African American than Hispanic youth, but the differences are not statistically significant. These findings support the thesis that, like other strains, discrimination may not have to be experienced directly to influence offending.     

Effects of Firm-specific and Country-specific Advantages on Relative Acquisition Size in Service Sector Cross-Border Acquisitions: An Empirical Examination

Using a sample of 348 service sector cross-border acquisitions by U.S. firms in 44 countries during 1990–2006, our study seeks to identify factors that influence relative acquisition size (acquisition transaction value as a percentage of acquiring firm's asset value). Our findings indicate that firm-specific advantages (FSAs) in the form of available financial slack and target industry knowledge were positively associated with relative acquisition size. However, contrary to expectations, we observed a negative relationship between cross-border acquisition experience and relative acquisition size. In addition, our results suggest that country-specific advantages (CSAs) associated with higher market potential, lower political risk, and greater cultural similarity contributed to increased relative acquisition size in service industry cross-border acquisitions. Finally, our analysis reveals that the relationship between available financial slack and relative acquisition size is contingent on cultural similarity with the relationship being more pronounced when cultural similarity is high.     

疲劳裂纹扩展试验裂纹图像采集系统

针对目前金属疲劳裂纹扩展检测方法存在效率低、操作繁琐、精度不高，不能实现实时性等缺点，文章提出了基 于机器视觉的裂纹检测方法。根据金属疲劳裂纹扩展试验过程中裂纹图像的采集要求，设计了摄像头位置可自动调整 的疲劳裂纹图像采集系统，包括摄像头安装运动装置，裂纹图像采集装置以及摄像头运动控制系统。图像采集装置由高 分辨率黑白面阵CCD摄像头、光学镜头，光源照明装置和图像采集卡组成，前3者安装在摄像头支架上，与摄像头运动 装置相连。摄像头运动装置中的X，Y，，Z轴运动机构由步进电机带动滚珠导轨机构。在基于ARM技术的运动控制系统 的控制下摄像头可沿X，Y，，Z轴作高精度直线运动，实现和试件之间精确位置的调整。实验结果表明，所设计的系统可 采集到疲劳裂纹扩展试验过程中高清晰度、高分辨率的试件裂纹图像，满足下一步裂绞尺寸计算的要求；摄像头运动定 位精度可达到0. 02 mm，满足精确的系统聚焦、位置调整、跟踪采集的要求。     

京津冀协同发展背景下二语学习者语际语用能力提升策略研究

京津冀协同发展是近期华北地区的一个重要特点,这就意味着对科技人才的素质有了新的要求,对科技人才二语语际语用能力的要求也大大提高,而河北省大学生二语学习过程中的语际语用能力相对薄弱,缺乏竞争力;本文通过对在校大学生的语言策略培训,创造真实语言环境,改变传统课堂模式和教学内容,充分发挥学习者的潜力,提高语言应用能力和跨文化交际的能力,因而增强学习者的综合竞争力,以满足新的经济发展情况下对人才素质的要求。     

Ebola Virus Dose Response Model for Aerosolized Exposures: Insights from Primate Data

This study develops dose–response models for Ebolavirus using previously published data sets from the open literature. Two such articles were identified in which three different species of nonhuman primates were challenged by aerosolized Ebolavirus in order to study pathology and clinical disease progression. Dose groups were combined and pooled across each study in order to facilitate modeling. The endpoint of each experiment was death. The exponential and exact beta-Poisson models were fit to the data using maximum likelihood estimation. The exact beta-Poisson was deemed the recommended model because it more closely approximated the probability of response at low doses though both models provided a good fit. Although transmission is generally considered to be dominated by person-to-person contact, aerosolization is a possible route of exposure. If possible, this route of exposure could be particularly concerning for persons in occupational roles managing contaminated liquid wastes from patients being treated for Ebola infection and the wastewater community responsible for disinfection. Therefore, this study produces a necessary mathematical relationship between exposure dose and risk of death for the inhalation route of exposure that can support quantitative microbial risk assessment aimed at informing risk mitigation strategies including personal protection policies against occupational exposures.     

信任对农民创业机会识别的影响

基于信任视角,构建农民创业者信任对创业机会识别的理论分析框架,运用链式多重中介方法,对浙江、安徽、河南和陕西4省880份农民创业者访谈数据进行实证分析,结果发现:信任能显著提高农民创业机会识别;农民创业者信任能通过外部知识获取与创业警觉性对创业机会识别产生间接影响,其作用路径有三条:外部知识获取的部分中介作用、创业警觉性的部分中介作用及外部知识获取与创业警觉性的链式中介作用。因此,政府应完善农民创业相关规章与制度;推进农村文化建设,提高信任水平;增加农民创业知识与技能的供给,培养农民创业者的机会警觉性。     

Managing Demand Uncertainty through Core Acquisition in Remanufacturing

We discuss the optimal raw material acquisition strategy for a third party remanufacturer (3PR). We specifically investigate whether a 3PR should acquire used products or cores in bulk with uncertain quality levels, or in sorted grades with known quality levels; and whether to acquire and remanufacture cores before the demand is realized (planned acquisition), or after the demand is realized (reactive acquisition), or on both occasions (sequential acquisition). When only sorted cores are acquired, we find that, (i) it is optimal to acquire cores in multiple grades to balance acquisition and remanufacturing costs; (ii) if reactive acquisition is possible, it reduces the assortment size (number of grades in which cores are acquired) and the total inventory acquired in the planned acquisition; and (iii) the optimal portfolio of grades to acquire and the optimal acquisition and remanufacturing quantities of these grades can be determined analytically. When bulk cores are acquired in addition to sorted cores, the property of reduction in assortment size of the planned acquisition is preserved. We also show that the 3PR should acquire only a fraction of the demand in planned acquisition, and leave the rest for reactive acquisition. This fraction changes during the lifecycle of a remanufactured product. Using a combination of empirical and realistic data from a smartphone remanufacturer we show that sequential acquisition increases expected profit by up to 8% and 27% over only planned and only reactive acquisitions respectively, and reduces the inventory acquired by up to 21% over only planned acquisition.     

Blood Money: Bayer’s Inventory of HIV-Contaminated Blood Products and Third World Hemophiliacs

This article presents an overlooked case of research misconduct and violations of basic principles of medical and business ethics. When Bayer’s Cutter Laboratories realized that their blood products, Factor VIII and IX or antihemophiliac factor (AHF), were contaminated with human immunodeficiency virus (HIV), the financial investment in the product was considered too high to destroy the inventory. Cutter misrepresented the results of its own research and sold the contaminated AHF to overseas markets in Asia and Latin America without the precaution of heat treating the product recommended for eliminating the risk. As a consequence, hemophiliacs who infused the HIV-contaminated Factor VIII and IX tested positive for HIV and developed AIDS.     

70年代国外习得顺序研究综述(二)

本文回顾了70年代句子习得顺序的相关研究,主要涉及否定句、疑问句的习得顺序的相关研究,也提及70年代提出的关于关系从句的习得顺序的三大研究假设,最后指出70年代习得顺序研究的意义和不足之处以及之后该领域的主要研究动态。