Determinants of maltreatment substantiation in a sample of infants involved with the child welfare system

Children under one year of age are highly vulnerable to child maltreatment, which can lead to serious immediate and long-term physical and mental health consequences. Child welfare workers encounter unique challenges when assessing allegations of maltreatment involving infants. This study identifies correlates of maltreatment substantiation in a sample of 793 infants less than one year of age investigated by child welfare. It is based on data from the 2003 Canadian Incidence Study of Reported Child Abuse and Neglect (CIS-2003), a national study of reports of child maltreatment. The analysis consisted of two stages. First, bivariate analyses were conducted using unadjusted odds ratios and chi-square tests on variables known to be associated with substantiation. In the second stage, a logistic regression was performed to examine these associations in a multivariate model.Multivariate findings suggest that certain vulnerabilities present in the primary caregiver, such as substance abuse and few social supports, as well as the child's positive toxicology at birth are associated with substantiated infant maltreatment. Exposure to domestic violence, which is reported mostly by the police, and physical harm stemming from maltreatment are strongly associated with substantiation, whereas reports of physical abuse and neglect have an inverse relationship. The authors discuss these results and implications for policy and programs.     

Novel nomogram based on risk factors of chronic obstructive pulmonary disease (COPD) using a naïve Bayesian classifier model

In this paper, we identified risk factors for chronic obstructive pulmonary disease (COPD) and proposed a nomogram for COPD. Data were from the 6th Korean National Health and Nutrition Examination Survey (2013–2015). First, a chi-square test was performed to identify risk factors about incidence of COPD. A nomogram was then constructed using the naïve Bayesian classifier model in order to visualize risk factors of COPD. The nomogram shows that asthma had the strongest effect on COPD incidence. We additionally compared Bayesian nomogram with logistic regression model nomogram. Finally, a ROC curve and calibration plot were used to assess the nomogram.     

阜新三次产业系统实证分析

研究阜新这样衰落地区的经济发展具有重要的现实意义。选择了国内生产总值作为研究对象 ,系统地分析了阜新三次产业的发展规律及发展现状     

Reconstructing the incidence of human immunodeficiency virus (HIV) in Hong Kong by using data from HIV positive tests and diagnoses of acquired immune deficiency syndrome

Summary. The human immunodeficiency virus–acquired immune deficiency syndrome (HIV–AIDS) epidemic in Hong Kong has been under surveillance in the form of voluntary reporting since 1984. However, there has been little discussion or research on the reconstruction of the HIV incidence curve. This paper is the first to use a modified back-projection method to estimate the incidence of HIV in Hong Kong on the basis of the number of positive HIV tests only. The model proposed has several advantages over the original back-projection method based on AIDS data only. First, not all HIV-infected individuals will develop AIDS by the time of analysis, but some of them may undertake an HIV test; therefore, the HIV data set contains more information than the AIDS data set. Second, the HIV diagnosis curve usually has a smoother pattern than the AIDS diagnosis curve, as it is not affected by redefinition of AIDS. Third, the time to positive HIV diagnosis is unlikely to be affected by treatment effects, as it is unlikely that an individual receives medication before the diagnosis of HIV. Fourth, the induction period from HIV infection to the first HIV positive test is usually shorter than the incubation period which is from HIV infection to diagnosis of AIDS. With a shorter induction period, more information becomes available for estimating the HIV incidence curve. Finally, this method requires the number of positive HIV diagnoses only, which is readily available from HIV–AIDS surveillance systems in many countries. It is estimated that, in Hong Kong, the cumulative number of HIV infections during the period 1979–2000 is about 2600, whereas an estimate based only on AIDS data seems to give an underestimate.     

Semiparametric estimation of the cumulative incidence function under competing risks and left-truncated sampling

In this article, we propose semiparametric methods to estimate the cumulative incidence function of two dependent competing risks for left-truncated and right-censored data. The proposed method is based on work by Huang and Wang (1995). We extend previous model by allowing for a general parametric truncation distribution and a third competing risk before recruitment. Based on work by Vardi (1989), several iterative algorithms are proposed to obtain the semiparametric estimates of cumulative incidence functions. The asymptotic properties of the semiparametric estimators are derived. Simulation results show that a semiparametric approach assuming the parametric truncation distribution is correctly specified produces estimates with smaller mean squared error than those obtained in a fully nonparametric model.     

基于间接税转嫁的中国要素收入有效税负测算

 本文基于税负转嫁的视角,构造了要素收入有效税率的核算框架,详细界定了各种要素税负的核算范围,并实证测算了1995-2010年中国劳动与资本的实际有效税负。研究发现,与世界发达国家相比,我国的要素税负也并不算低。其中,间接税对居民消费的转嫁作用、增值税进项抵扣环节的重复计税是劳动、资本有效税率攀升的重要原因。     

Simple pilot procedures for the avoidance of disconnected experimental designs

Summary.  Two simple pilot procedures are proposed for avoiding the problem of dealing with a disconnected experimental design. Both procedures should be carried out on the selected design before any experimentation is considered. The first procedure is a check that the suggested design is connected with respect to treatments. This makes use of the information matrix for the model and provides feed-back on a disconnected design. The second procedure specifies which observations are influential in causing a connected design to become disconnected, with respect to any set of parameter effects, if these observations are lost during the experimental period. This specification is found by examining the projection matrix for the model. These pilot procedures are illustrated by several examples.     

Modelling forces of infection by using monotone local polynomials

Summary. On the basis of serological data from prevalence studies of rubella, mumps and hepatitis A, the paper describes a flexible local maximum likelihood method for the estimation of the rate at which susceptible individuals acquire infection at different ages. In contrast with parametric models that have been used before in the literature, the local polynomial likelihood method allows this age-dependent force of infection to be modelled without making any assumptions about the parametric structure. Moreover, this method allows for simultaneous nonparametric estimation of age-specific incidence and prevalence. Unconstrained models may lead to negative estimates for the force of infection at certain ages. To overcome this problem and to guarantee maximal flexibility, the local smoother can be constrained to be monotone. It turns out that different parametric and nonparametric estimates of the force of infection can exhibit considerably different qualitative features like location and the number of maxima, emphasizing the importance of a well-chosen flexible statistical model.     

A review and discussion of prospective statistical surveillance in public health

Summary. A review of methods suggested in the literature for sequential detection of changes in public health surveillance data is presented. Many researchers have noted the need for prospective methods. In recent years there has been an increased interest in both the statistical and the epidemiological literature concerning this type of problem. However, most of the vast literature in public health monitoring deals with retrospective methods, especially spatial methods. Evaluations with respect to the statistical properties of interest for prospective surveillance are rare. The special aspects of prospective statistical surveillance and different ways of evaluating such methods are described. Attention is given to methods that include only the time domain as well as methods for detection where observations have a spatial structure. In the case of surveillance of a change in a Poisson process the likelihood ratio method and the Shiryaev–Roberts method are derived.     

A formal test for the stationarity of the incidence rate using data from a prevalent cohort study with follow-up

In a prevalent cohort study with follow-up, the incidence process is not directly observed since only the onset times of prevalent cases can be ascertained. Assessing the “stationarity” of the underlying incidence process can be important for at least three reasons, including an improvement in efficiency when estimating the survivor function. We propose, for the first time, a formal test for stationarity using data from a prevalent cohort study with follow-up. The test makes use of a characterization of stationarity, an extension of this characterization developed in this paper, and of a test for matched pairs of right censored data. We report the results from a power study assuming varying degrees of departure from the null hypothesis of stationarity. The test is also applied to data obtained as part of the Canadian Study of Health and Aging (CSHA) to verify whether the incidence rate of dementia amongst the elderly in Canada has remained constant.