The effect of visualization method on the performance of simulated microsurgery tasks

The operating microscopes may be a significant cause of fatigue and discomfort in surgeons. The need for the microscope to be placed over the operating field forces surgeons to remain at the microscope's eyepieces at an uncomfortable posture for the entirety of the surgery. This study compared the effects on microsurgical task performance for four visualization methods: a monocular microscope, a binocular microscope, a three-dimensional (3D) flat-panel television display and a two-dimensional (2D) flat-panel television display. Eleven subjects each performed two microsurgical tasks and their performance was documented by video camera. The statistical analysis performed indicated utilization of the microscope as a visualization method increased subject performance. No significant difference in performance between the 2D and stereoscopic visualization methods.     

A Bayesian sequential design with binary outcome

Several researchers have proposed solutions to control type I error rate in sequential designs. The use of Bayesian sequential design becomes more common; however, these designs are subject to inflation of the type I error rate. We propose a Bayesian sequential design for binary outcome using an alpha‐spending function to control the overall type I error rate. Algorithms are presented for calculating critical values and power for the proposed designs. We also propose a new stopping rule for futility. Sensitivity analysis is implemented for assessing the effects of varying the parameters of the prior distribution and maximum total sample size on critical values. Alpha‐spending functions are compared using power and actual sample size through simulations. Further simulations show that, when total sample size is fixed, the proposed design has greater power than the traditional Bayesian sequential design, which sets equal stopping bounds at all interim analyses. We also find that the proposed design with the new stopping for futility rule results in greater power and can stop earlier with a smaller actual sample size, compared with the traditional stopping rule for futility when all other conditions are held constant. Finally, we apply the proposed method to a real data set and compare the results with traditional designs.     

新奥尔良的发展:一部环境灾难史

2005年,卡特里娜和丽塔两大飓风侵袭路易斯安那州的新奥尔良市,成为美国历史上造成损失最大的灾难之一。这一貌似自然灾害的危害事件,其实孕育于新奥尔良的长期发展之中。一部新奥尔良发展史,既是人类利用土地、河流、森林、海洋等自然实体并与自然环境搏斗以建立城市、发展航运和工商业的历史,也是这些自然实体及其哺育的众多生命不断受侵蚀以至戕害的历史。这既是一部人类文明史,也是一部环境灾难史。在这里,人类借助水利工程控制自然而建立起来的文明,由于损害了生态系统的健康,削弱了其自然防护能力,结果反而加剧了人类无法避免的自然灾害的危害。因此,飓风造成的损失不只是取决于风暴之力,也取决于人们对土地的所作所为。而保持新奥尔良生机的努力,并不需要一味地与自然相搏,与自然合作,也是一种有益的尝试。     

MARKET STRUCTURE AND MEDIA DIVERSITY

We estimate a mixed logit model of the demand for local news service. Results provide evidence that suggest the representative consumer values more diverse news, more coverage of multicultural issues, and more information on community news, and has a distaste for advertising. Demand estimates are used to calculate the impact on consumer welfare from a marginal decrease in the number of independent television stations that lowers the amount of diversity, multiculturalism, community news, and advertising. Consumer welfare decreases, but the losses are smaller in large markets. For example, small‐market consumers lose $45 million annually while large‐market consumers lose $13 million. (JEL C9, C25, L13, L82, L96)     

The U.S. Health System and Immigration: An Institutional Interpretation1

We examine the institutions that comprise the U.S. health system and their relationship to a surging immigrant population. The clash between the system and this human flow originates in the large number of immigrants who are unauthorized, poor, and uninsured and, hence, unable to access a system largely based on ability to pay. Basic concepts from sociological theory are brought to bear on the analysis of this clash and its consequences. Data from a recently completed study of health institutions in three areas of the United States are used as an empirical basis to illustrate various aspects of this complex relation. Implications of our results for theory and future health policy are discussed.     

Some indications of limits to framing the policy preferences of the civically engaged: Interplay of social capital,race attitudes,and social justice frames

Our experiment, which tested support for a hypothetical social welfare program, found that the civically engaged as a whole were resistant to social justice framing employing universalistic versus particularistic standards. We suggest the lack of a framing effect was due to the use of a preexisting, shared “symbolic racism” frame. Social justice framing did succeed for those whose attitudes toward symbolic racism were ambivalent or neutral. Other factors including sex, income level, political participation, and ideology significantly influenced choice. These results provide some indications of limits to experimental framing of policy preferences of the civically engaged in their institutional settings.     

Conceptual, computational and inferential benefits of the missing data perspective in applied and theoretical statistical problems

This article advocates the following perspective: When confronting a scientific problem, the field of statistics enters by viewing the problem as one where the scientific answer could be calculated if some missing data, hypothetical or real, were available. Thus, statistical effort should be devoted to three steps:

1. formulate the missing data that would allow this calculation,
2. stochastically fill in these missing data, and
3. do the calculations as if the filled-in data were available.

This presentation discusses: conceptual benefits, such as for causal inference using potential outcomes; computational benefits, such as afforded by using the EM algorithm and related data augmentation methods based on MCMC; and inferential benefits, such as valid interval estimation and assessment of assumptions based on multiple imputation.     

《认一论大纲》译注

《认一论大纲》是伊斯兰教义学古典名著,距今已有1300多年了.文中涉及到伊斯兰教义学、伊斯兰哲学长期以来所探讨的诸多重大问题,对于伊斯兰哲学、教义学、凯拉姆学、苏非学即中国穆斯林哲学思想和经堂教育的研究,都具有较高的历史文献价值和参考价值.