Regression Models and Risk Estimation for Mixed Discrete and Continuous Outcomes in Developmental Toxicology

Multivariate dose-response models have recently been proposed for developmental toxicity data to simultaneously model malformation incidence (a binary outcome), and reductions in fetal weight (a continuous outcome). In this and other applications, the binary outcome often represents a dichotomization of another outcome or a composite of outcomes, which facilitates analysis. For example, in Segment II developmental toxicology studies, multiple malformation types (i.e., external, visceral, skeletal) are evaluated on each fetus; malformation status may also be ordinally measured (e.g., normal, signs of variation, full malformation). A model is proposed is for fetal weight and multiple malformation variables measured on an ordinal scale, where the correlations between the outcomes and between the offspring within a litter are taken into account. Fully specifying the joint distribution of outcomes within a litter is avoided by specifying only the distribution of the multivariate outcome for each fetus and using generalized estimating equation methodology to account for correlations due to litter clustering. The correlations between the outcomes are required to characterize joint risk to the fetus, and are therefore a focus of inference. Dose-response models and their application to quantitative risk assessment are illustrated using data from a recent developmental toxicology experiment of ethylene oxide in mice.     

对政府分配功能和税收分配功能的重新界定

重新界定政府分配功能应明确两点:一是政府分配功能存在于国民收入分配的全过程;二是现实中政府分配功能具有二重性,即积极作用和负面影响。重新界定税收分配功能应明确两点:一是税收分配功能存在于国民收入分配的全过程;二是税收分配功能有多种作用形式。     

行为效能、人地情感与旅游者环境负责行为意愿:一个基于计划行为理论的改进模型

“环境友好型”旅游者对旅游地和景区的可持续发展具有重要意义。通过将“感知行为效能”和“地方依恋”这两个与旅游情境下环境负责行为密切相关的因素纳入计划行为理论模型,一个解释和预测旅游者自发的环境负责行为意愿的整体模型得以构建。针对杭州西溪国家湿地公园251位游客样本的实证研究显示:旅游者环境负责行为意愿不仅取决于其对自身得失的理性评估,还受到感知行为效能因素和情感因素的显著影响,尤其是旅游者与景区之间的情感纽带和心理认同对其环保行为态度和行为意愿均具有积极影响。基于上述结论,我国旅游地和景区可持续发展应突破传统的管理规制路径,探索通过感情维系、效能培养、规范树立等创新措施,培育和引导旅游者自发采取有利于生态环境保护的行为。     

A pragmatic dose‐finding approach using short‐term surrogate efficacy outcomes to evaluate binary efficacy and toxicity outcomes in phase I cancer clinical trials

There is a growing need for study designs that can evaluate efficacy and toxicity outcomes simultaneously in phase I or phase I/II cancer clinical trials. Many dose‐finding approaches have been proposed; however, most of these approaches assume binary efficacy and toxicity outcomes, such as dose‐limiting toxicity (DLT), and objective responses. DLTs are often defined for short time periods. In contrast, objective responses are often defined for longer periods because of practical limitations on confirmation and the criteria used to define ‘confirmation’. This means that studies have to be carried out for unacceptably long periods of time. Previous studies have not proposed a satisfactory solution to this specific problem. Furthermore, this problem may be a barrier for practitioners who want to implement notable previous dose‐finding approaches. To cope with this problem, we propose an approach using unconfirmed early responses as the surrogate efficacy outcome for the confirmed outcome. Because it is reasonable to expect moderate positive correlation between the two outcomes and the method replaces the surrogate outcome with the confirmed outcome once it becomes available, the proposed approach can reduce irrelevant dose selection and accumulation of bias. Moreover, it is also expected that it can significantly shorten study duration. Using simulation studies, we demonstrate the positive utility of the proposed approach and provide three variations of it, all of which can be easily implemented with modified likelihood functions and outcome variable definitions. Copyright © 2013 John Wiley & Sons, Ltd.     

A bivariate Bayesian dose‐finding procedure applied to a seamless phase I/II trial in rheumatoid arthritis

We describe a dose escalation procedure for a combined phase I/II clinical trial. The procedure is based on a Bayesian model for the joint distribution of the occurrence of a dose limiting event and of some indicator of efficacy (both considered binary variables), making no assumptions other than monotonicity. Thus, the chances of each outcome are assumed to be non‐decreasing in dose level. We applied the procedure to the design of a placebo‐controlled, sequential trial in rheumatoid arthritis, in each stage of which patients were randomized between placebo and all dose levels that currently appeared safe and non‐futile. On the basis of data from a pilot study, we constructed five different scenarios for the dose–response relationships under which we simulated the trial and assessed the performance of the procedure. The new design appears to have satisfactory operating characteristics and can be adapted to the requirements of a range of trial situations. Copyright © 2012 John Wiley & Sons, Ltd.     

A discrete-time and finite-state Markov Chain model for association football matches

A birth process model proposed by Dixon and Robinson has been widely used in football spread betting market. However, multiple goals in a minute are permitted in the model, which does not conform to historical record. Moreover, it is difficult to calculate the outcome probability of the process accurately. The article presents a discrete-time and finite-state Markov chain model for real-time forecast of football matches and a recursive algorithm is derived to calculate the outcome probability accurately. The empirical study shows that the proposed model outperforms the models of Dixon and Robinson and Dixon and Coles.     

浅谈言语交际中的幽默技巧

随着时代的发展、社会的进步,口才的重要性越来越为人们所重视,言语幽默成为为衡量口才的最高标准。因而言语交际中幽默技巧的把握与运用就显得尤为重要。     

What is Adult Attachment?

This paper explores the concept of adult attachment. Although attachment theory is now getting a great deal of attention, there is not yet a clear picture of what it means to be attached in adulthood or what the clinical applications of the approach might be. Using Bowlby’s distinctive ethological-evolutionary framework and updating it with findings from neurobiology and attachment research, it is proposed there is an attachment behavioral system that operates throughout the lives of adults and that this changes the way we understand our clients’ distress and carry out psychotherapy.

从社会认知职业理论视角探讨职业结果预期对职业兴趣的影响

以海南310名旅游管理专业四年级本科生为研究样本,从社会认知职业理论(简称SCCT理论)的视角,实证检验了其对旅游职业所抱有的兴趣变量(因变量)与其对选择旅游职业所做出的8个结果预期(自变量)之间的因果关系。研究结果不但佐证了SCCT理论就职业兴趣和职业结果预期之关系所做出的理论假设,而且还拓宽了该理论假设在旅游人力资源领域的适用范围。