Conditional Functional Principal Components Analysis

Abstract.  This work proposes an extension of the functional principal components analysis (FPCA) or Karhunen–Loève expansion, which can take into account non-parametrically the effects of an additional covariate. Such models can also be interpreted as non-parametric mixed effect models for functional data. We propose estimators based on kernel smoothers and a data-driven selection procedure of the smoothing parameters based on a two-step cross-validation criterion. The conditional FPCA is illustrated with the analysis of a data set consisting of egg laying curves for female fruit flies. Convergence rates are given for estimators of the conditional mean function and the conditional covariance operator when the entire curves are collected. Almost sure convergence is also proven when one observes discretized noisy sample paths only. A simulation study allows us to check the good behaviour of the estimators.     

美国高技术城市成功因素探析

美国高技术城市的成功是多种因素综合作用的结果。大学、尤其是高水平的研究型大学不仅是重要的研发资源,而且是高技术企业高素质劳动力和潜在的创业者的主要来源。风险投资为高技术企业注入资金,参与运营,起着积极的推动作用。美国联邦政府的国防开支和其他领域的研发开支、州政府的诸多举措均有力地推动了高技术城市的发展。城市的集聚效应也发挥了明显的作用,是讨论美国高技术城市成功不可或缺的重要因素。此外,美国高技术城市生活质量在吸引高素质人才方面的优势也不容忽视。     

The effects of job displacement on job quality: Findings from the Wisconsin Longitudinal Study

This study examines the extent to which job displacement divides the career experiences for a cohort of workers. Previous studies of job displacement find nontrivial economic losses for displaced workers, but the effects of displacement on “non-economic” properties of jobs have been largely overlooked. Results using the Wisconsin Longitudinal Study indicate that workers who were displaced have lower levels of occupational status, job authority, and employer-offered pension and health insurance than they would have had had they not been displaced. Difference-in-differences estimates, which control for temporally-invariant unobserved heterogeneity, are generally larger than cross-sectional estimates; still, there is a close correspondence of estimates across a range of methodological approaches attesting to the robustness of the estimates in the face of various technical assumptions and model specifications. Effects of displacement on job quality also exhibit conditioning by gender, education, occupation, and industry: while less educated, blue collar and manufacturing workers experience significant losses for employer-offered benefits, more educated, upper white collar and non-manufacturing workers experience significant losses for occupational status, job autonomy, and job authority.     

目击事件对目击证人记忆的错误信息效应研究

通过操作误导事件后的信息这一变量,考察有无误导事件后的信息对目击证人原始事件记忆效果的影响,以及目击证人对自己回答的自信心方面的影响。实验结果表明:(1)误导事件后的信息使被试对原始事件产生错误记忆;(2)误导事件后的信息对主体问题没有影响,但对情境问题的影响达到显著水平;(3)是否接受误导事件后的信息与目击证人的自信之间没有相关,但是不同的问题类型以及是否回答正确,与目击证人的自信有密切关系。     

大学生考研热透析

文章分析了当前考研热中考生的各种动机和心态，并从端正学风、班风、校风的角度分析了大学生考研对考研生本人的积极作用以及对考研生所在班集体的积极的影响作用，指出了目前考研热中存在的一些问题。     

基于面板数据的中国农业信贷绩效研究

文章基于面板数据,利用固定效应估计法和随机效应估计法,对我国在1999年至2002年间农业信贷的绩效作出实证研究。研究结果表明,我国农业信贷配置机制应作进一步的调整,以便提高农业信贷的绩效,支持农业发展。     

Effects of non-normality on the power function in a one-way random model

The effects of non-normality on type-I and type-II errors in a one-way random model are investigated for moderate departures from normality. It is found that the probabilities of both errors are more sensitive to the kurtosis of between group effects than that of within group effects.     

The Management of Risk: Application to the Welding Industry

The management of health risk in the welding industry is considered based on a discussion of the major sources of harm to welders arising from their employment (e.g., accidents and inhalation of fumes and gases). It is shown that present methods neither enable the assessment of the societal and human costs involved, nor permit the specific association of delayed health effects to occupational fume exposures. Reported accidents usually occur early in the working experience and contribute to a large number of working days lost, while fume exposures may contribute to a reduction in life quality which is poorly defined. It is concluded that risk management can only be attempted after much more information is made available concerning the origin, nature, and duration of health effects, especially as related to individual welding technologies and applications.     

中华菜名比喻艺术管窥

中华菜名中的比喻精巧优美、形神兼备,既有语言精炼、结构紧凑的暗喻,又有惟妙惟肖、独具特色的借喻,其民俗喻体熔铸、凸显了中华文化神韵,包含有取形寓意、雅致高洁的植物类喻体,动静融合、风情万种的动物类喻体,源远流长、底蕴涌动的神异类喻体等,它们既能提升菜肴的审美情趣,提高菜名的艺术品位,又能激发食用者的心理想像,表现汉民族的具象思维特色,从而产生了彰显人文魅力,取得多重效应的功能。     

Let's Call it Quits: Break‐Even Effects in the Decision to Stop Taking Risks

“Chasing” behavior, whereby individuals, driven by a desire to break even, continue a risky activity (RA) despite incurring large losses, is a commonly observed phenomenon. We examine whether the desire to break even plays a wider role in decisions to stop engaging in financially motivated RA in a naturalistic setting. We test hypotheses, motivated by this research question, using a large data set: 707,152 transactions of 5,379 individual financial market spread traders between September 2004 and April 2013. The results indicate strong effects of changes in wealth around the break‐even point on the decision to cease an RA. An important mediating factor was the individual's historical long‐term performance. Those with a more profitable trading history were less affected by a fall in cash balance below the break‐even point compared to those who had been less profitable. We observe that break‐even points play an important role in the decision of nonpathological risk takers to stop RAs. It is possible, therefore, that these nonpathological cognitive processes, when occurring in extrema, may result in pathological gambling behavior such as “chasing.” Our data set focuses on RAs in financial markets and, consequently, we discuss the implications for institutions and regulators in the effective management of risk taking in markets. We also suggest that there may be a need to consider carefully the nature and role of “break‐even points” associated with a broader range of nonfinancially‐focused risk‐taking activities, such as smoking and substance abuse.