论Schwarzschild黑洞的熵

利用二维球面简并气体模型，证实了Ｓｃｈｗａｒｚｓｃｈｉｌｄ黑洞的熵就是其视界物质的熵．     

GIS系统在高校房屋管理中的应用

由于GIS可以通过测量、遥感等手段将获得的数据进行录入分析,并显示地理空间信息,使其在各个领域内都得到广泛应用。在结合GIS领域在管理领域发展趋势的基础上,提出了关于GIS的高校房屋管理系统的分层结构以及主要功能,并补充了其对高校内学生宿舍以及教师公寓系统的管理内容,从而建立了基于GIS的高校房屋管理的基本模型。同时,这种直观的管理模式、简洁的查询登记方式将大大减轻管理人员的工作量、提高工作人员的工作效率,使得研究工作的开展能为GIS房屋管理系统的应用提供参考。     

Estimation of group means in generalized linear mixed models

In this study, we investigate the concept of the mean response for a treatment group mean as well as its estimation and prediction for generalized linear models with a subject‐wise random effect. Generalized linear models are commonly used to analyze categorical data. The model‐based mean for a treatment group usually estimates the response at the mean covariate. However, the mean response for the treatment group for studied population is at least equally important in the context of clinical trials. New methods were proposed to estimate such a mean response in generalized linear models; however, this has only been done when there are no random effects in the model. We suggest that, in a generalized linear mixed model (GLMM), there are at least two possible definitions of a treatment group mean response that can serve as estimation/prediction targets. The estimation of these treatment group means is important for healthcare professionals to be able to understand the absolute benefit vs risk. For both of these treatment group means, we propose a new set of methods that suggests how to estimate/predict both of them in a GLMMs with a univariate subject‐wise random effect. Our methods also suggest an easy way of constructing corresponding confidence and prediction intervals for both possible treatment group means. Simulations show that proposed confidence and prediction intervals provide correct empirical coverage probability under most circumstances. Proposed methods have also been applied to analyze hypoglycemia data from diabetes clinical trials.     

保护性医疗及其行使对策

保护性医疗作为我国临床实践中长期存在的医疗措施，近年来开始受到较多质疑。在医学模式转型背景下，保护性医疗面临与患者知情同意权、新医患关系模式及自身实效性问题等的矛盾与困境。为更合理地适用保护性医疗，应将患者适用保护性医疗必要性评估作为前置条件，并根据病程变化做出调整。     

A generalized model of logistic regression for clustered data

This paper proposes a generalized logistic regression model that can account for the correlation among responses on subunits. The subunits may arise as data on multiple observations within an individual. This method generalizes earlier work by Rosner (1984 a,b) and others. Methodological generalizations include: (1) the use of the more general Polya-Eggenberger distribution instead of the beta-binomial distribution to model the correlation structure, so that cases with negative, positive, or zero intraclass correlation can be handled; (2) a stepwise approach; (3) linear and non-linear regression; and, (4) the inclusion of the case of a truncated distribution. The model can accommodate missing data and covariates on the unit and subunit level. The derivative-free simplex algorithm is used to estimate the parameters.

The model is applied to data describing the progression of obstruction in coronary disease where multiple arterial segments are studied for each patient. The correlation in response that may exist for these multiple segments is accounted for in the analyses while attempting to examine associations with individual-specific (e.g., history of diabetes) and segment-specific (e.g., initial percent stenosis) covariates. Analyses were performed on a data set describing 382 patients with unoperated coronary artery disease and two coronary angiograms separated by at least one month and on a data set describing 284 patients undergoing percutaneous transluminal coronary angioplasty and studied by coronary angiograms.     

Uniform Inference on Quantile Effects under Sharp Regression Discontinuity Designs

ABSTRACT

This study develops methods for conducting uniform inference on quantile treatment effects for sharp regression discontinuity designs. We develop a score test for the treatment significance hypothesis and Wald-type tests for the hypotheses related to treatment significance, homogeneity, and unambiguity. The bias from the nonparametric estimation is studied in detail. In particular, we show that under some conditions, the asymptotic distribution of the score test is unaffected by the bias, without under-smoothing. For situations where the conditions can be restrictive, we incorporate a bias correction into the Wald tests and account for the estimation uncertainty. We also provide a procedure for constructing uniform confidence bands for quantile treatment effects. As an empirical application, we use the proposed methods to study the effect of cash-on-hand on unemployment duration. The results reveal pronounced treatment heterogeneity and also emphasize the importance of considering the long-term unemployed.     

惟玉为葬 惟玉为礼

牛河梁遗址所反映的墓葬形制是墓有中心大墓、大墓、中小型墓、附属墓的等级制.随葬只有玉器,"惟玉为葬",而且中心大墓的葬玉档次高、品质好,数量多.     

铬对海洋生物的影响

铬(Cr)是生物代谢活动中的一个基本营养元素,又是一个很毒的重金属元素。海水中溶解态铬主要以Cr(Ⅲ)、Cr(Ⅵ)和有机铬等形态存在;铬元素在海洋生物体内分布广泛,铬对单细胞藻类有一定的毒害作用,不同种类的单细胞藻类对铬元素有不同程度的富集作用,海洋细菌可将无机铬转化为有机铬;近年来,含铬的饲料已应用于水产养殖业,海洋环境污染研究中也将铬作为监测指标之一。