从五个方面介绍海明威

雅克·巴赞在他一九四五年所著的《美国教师》一书中主张,为了鼓励年轻人阅读,应该允许他们有什么书就读什么书。他还说即使是劣等怍品也是好的。此话也许有道理,但在很多情况下,向年轻的读者介绍一位象海明威那样身分的作家,对他们阅读的开始阶段会有更好的影响。海明威大概是世界范围内作品流传最广、最受尊敬的二三位作家之一,把他的作品作为阅读的起点,可谓终身的乐趣和享受。结合以下五个方面对海明威的介绍,初读者可以加深对他作品的理解。     

A simple two-stage design for quantitative responses with application to a study in diabetic neuropathic pain

Two-stage designs offer substantial advantages for early phase II studies. The interim analysis following the first stage allows the study to be stopped for futility, or more positively, it might lead to early progression to the trials needed for late phase II and phase III. If the study is to continue to its second stage, then there is an opportunity for a revision of the total sample size. Two-stage designs have been implemented widely in oncology studies in which there is a single treatment arm and patient responses are binary. In this paper the case of two-arm comparative studies in which responses are quantitative is considered. This setting is common in therapeutic areas other than oncology. It will be assumed that observations are normally distributed, but that there is some doubt concerning their standard deviation, motivating the need for sample size review. The work reported has been motivated by a study in diabetic neuropathic pain, and the development of the design for that trial is described in detail.     

Missing item imputation for quality-of-life instruments with application to asthma quality-of-life questionnaires

There has been increasing use of quality-of-life (QoL) instruments in drug development. Missing item values often occur in QoL data. A common approach to solve this problem is to impute the missing values before scoring. Several imputation procedures, such as imputing with the most correlated item and imputing with a row/column model or an item response model, have been proposed. We examine these procedures using data from two clinical trials, in which the original asthma quality-of-life questionnaire (AQLQ) and the miniAQLQ were used. We propose two modifications to existing procedures: truncating the imputed values to eliminate outliers and using the proportional odds model as the item response model for imputation. We also propose a novel imputation method based on a semi-parametric beta regression so that the imputed value is always in the correct range and illustrate how this approach can easily be implemented in commonly used statistical software. To compare these approaches, we deleted 5% of item values in the data according to three different missingness mechanisms, imputed them using these approaches and compared the imputed values with the true values. Our comparison showed that the row/column-model-based imputation with truncation generally performed better, whereas our new approach had better performance under a number scenarios.     

On the Assessment of Monte Carlo Error in Simulation-Based Statistical Analyses

Statistical experiments, more commonly referred to as Monte Carlo or simulation studies, are used to study the behavior of statistical methods and measures under controlled situations. Whereas recent computing and methodological advances have permitted increased efficiency in the simulation process, known as variance reduction, such experiments remain limited by their finite nature and hence are subject to uncertainty; when a simulation is run more than once, different results are obtained. However, virtually no emphasis has been placed on reporting the uncertainty, referred to here as Monte Carlo error, associated with simulation results in the published literature, or on justifying the number of replications used. These deserve broader consideration. Here we present a series of simple and practical methods for estimating Monte Carlo error as well as determining the number of replications required to achieve a desired level of accuracy. The issues and methods are demonstrated with two simple examples, one evaluating operating characteristics of the maximum likelihood estimator for the parameters in logistic regression and the other in the context of using the bootstrap to obtain 95% confidence intervals. The results suggest that in many settings, Monte Carlo error may be more substantial than traditionally thought.     

动画电影《九色鹿》中的敦煌壁画艺术与宗教文化

《九色鹿》是由中国上海美术电影制片厂出品的20世纪80年代的本土动画电影。敦煌壁画故事较为丰富,为动画创作者们提供了较多的素材,此片采用了敦煌壁画的形式,具有强烈的中国古代佛教绘画的风格。本文以《九色鹿》这部动画的风格作为切入点,从创作背景、传统元素、宗教神话影响等不同的角度剖析敦煌壁画对这部动画影片的影响。     

Application of an adaptive design to a randomized phase II selection trial in gastric cancer: a report of the study design

Randomized phase II selection trials seek to provide unbiased comparisons for the selection of the most promising treatment arm for evaluation in a future phase III trial. In this paper, we present an application of an adaptive design to a randomized phase II selection trial comparing three experimental treatments with a control arm in patients with advanced gastric cancer. The trial design continuously monitors multiple patient outcomes to protect future patients from treatments with unacceptably high toxicity and/or unacceptably low efficacy. We use a Bayesian approach to monitor the trial and carry out simulations to investigate operating characteristics of the trial design. The simulation study also evaluates the sensitivity of the design to the prior distribution by considering two alternative priors.     

Identifying the most successful dose (MSD) in dose-finding studies in cancer

For a dose finding study in cancer, the most successful dose (MSD), among a group of available doses, is that dose at which the overall success rate is the highest. This rate is the product of the rate of seeing non-toxicities together with the rate of tumor response. A successful dose finding trial in this context is one where we manage to identify the MSD in an efficient manner. In practice we may also need to consider algorithms for identifying the MSD which can incorporate certain restrictions, the most common restriction maintaining the estimated toxicity rate alone below some maximum rate. In this case the MSD may correspond to a different level than that for the unconstrained MSD and, in providing a final recommendation, it is important to underline that it is subject to the given constraint. We work with the approach described in O'Quigley et al. [Biometrics 2001; 57(4):1018-1029]. The focus of that work was dose finding in HIV where both information on toxicity and efficacy were almost immediately available. Recent cancer studies are beginning to fall under this same heading where, as before, toxicity can be quickly evaluated and, in addition, we can rely on biological markers or other measures of tumor response. Mindful of the particular context of cancer, our purpose here is to consider the methodology developed by O'Quigley et al. and its practical implementation. We also carry out a study on the doubly under-parameterized model, developed by O'Quigley et al. but not     

Time to listen: strategies to improve hospital-based postnatal care

BACKGROUND: In Australia and internationally, women report high levels of dissatisfaction with hospital-based postnatal care. AIM: To design and implement strategies to improve hospital-based postnatal care at a Sydney metropolitan hospital. METHOD: This was an Action Research study. In Phase One, midwives considered the literature and participated in group discussions and interviews to determine their perceptions of postnatal care and the factors that facilitate or hinder the provision of quality care. In Phase Two, midwives participated in 12 working group meetings to design strategies to improve care. RESULTS: Several important principles of postnatal care were described, including building a relationship with women, meeting their individual needs, being flexible in approach and providing continuity of care. 'Listening to women', 'being there,' and 'normalising experiences and expectations' were believed to be critical to achieving these principles. A key strategy 'One to One Time' was designed to provide women with an uninterrupted period of time each day with a midwife who was available to listen to their needs and concerns and discuss issues related to their health and that of their baby. CONCLUSION: Midwives designed and implemented strategies that they believed would improve in-hospital postnatal care.     

A model of substance abuse risk: adapting to the Sri Lankan context

This study translated and validated the Substance Use Risk Profile Scale (SURPS) among 13 to 18 year old Sri Lankan adolescents attending school. A standard systematic translation procedure was followed to translate the original SURPS into Sinhala language. A Delphi process was conducted to determine judgmental validity of Sinhala SURPS. Confirmatory factor analysis was performed to test the translated version against the original theoretical model of the SURPS. Test-retest and internal consistency were used to ensure reliability. A few terms in one of the items posed some difficulty in translating into Sinhala. Adequate judgmental validity was determined except for one item, which was modified to suit the Sri Lankan setting. The four subscales introversion/ hopelessness, impulsivity, sensation seeking and anxiety sensitivity showed satisfactory test-retest reliability estimates of .74, .68, .76, and .88, respectively. The Sinhala SURPS is applicable in Sri Lankan context. Several implications based on the results are discussed.     

Class, gender and time poverty: a time-use analysis of British workers' free time resources

Free time, that is, the time that remains at one's own discretion after conducting daily work and personal care activities, has been previously recognized as a 'primary good' and an important welfare resource that provides opportunities for participation in social life and leisure. However, recent years have witnessed an increasing preoccupation with the phenomenon of time poverty, drawing attention to the distribution of free time and its relationship to structural and family circumstances. In this article we propose a novel approach to the measurement of time poverty and document its occurrence amongst British workers. In line with previous literature, a conceptualization of time poverty as a relative lack of free time resources vis-à-vis other members of the community is adopted. However, unlike previous empirical studies, we investigate the differential configuration of time poverty on weekdays and weekend days, alongside indicators of the quality of free time, taking into account insights from theoretical and empirical work within the field of the sociology of time. Our analysis of the 2000 UK Time Use Survey highlights class and gender inequalities that have been missed by previous measurement approaches and demonstrates that, overall, working women experience multiple and more severe free time constraints, which may constitute an additional barrier for their leisure and social participation.