BAYESIAN MODEL SEARCH AND MULTILEVEL INFERENCE FOR SNP ASSOCIATION STUDIES

Technological advances in genotyping have given rise to hypothesis-based association studies of increasing scope. As a result, the scientific hypotheses addressed by these studies have become more complex and more difficult to address using existing analytic methodologies. Obstacles to analysis include inference in the face of multiple comparisons, complications arising from correlations among the SNPs (single nucleotide polymorphisms), choice of their genetic parametrization and missing data. In this paper we present an efficient Bayesian model search strategy that searches over the space of genetic markers and their genetic parametrization. The resulting method for Multilevel Inference of SNP Associations, MISA, allows computation of multilevel posterior probabilities and Bayes factors at the global, gene and SNP level, with the prior distribution on SNP inclusion in the model providing an intrinsic multiplicity correction. We use simulated data sets to characterize MISA's statistical power, and show that MISA has higher power to detect association than standard procedures. Using data from the North Carolina Ovarian Cancer Study (NCOCS), MISA identifies variants that were not identified by standard methods and have been externally "validated" in independent studies. We examine sensitivity of the NCOCS results to prior choice and method for imputing missing data. MISA is available in an R package on CRAN.     

Tail exponent estimation via broadband log density-quantile regression

Heavy tail probability distributions are important in many scientific disciplines such as hydrology, geology, and physics and therefore feature heavily in statistical practice. Rather than specifying a family of heavy-tailed distributions for a given application, it is more common to use a nonparametric approach, where the distributions are classified according to the tail behavior. Through the use of the logarithm of Parzen's density-quantile function, this work proposes a consistent, flexible estimator of the tail exponent. The approach we develop is based on a Fourier series estimator and allows for separate estimates of the left and right tail exponents. The theoretical properties for the tail exponent estimator are determined, and we also provide some results of independent interest that may be used to establish weak convergence of stochastic processes. We assess the practical performance of the method by exploring its finite sample properties in simulation studies. The overall performance is competitive with classical tail index estimators, and, in contrast, with these our method obtains somewhat better results in the case of lighter heavy-tailed distributions.     

A Demographic Model of Measles Epidemics

Liverpool, U.K., 1863--1900, has been used as a model to explore the interaction between measles epidemics and the population dynamics in an overcrowded community with inadequate nutrition using a non-linear model which allows the estimation of certain underlying demographic parameters. The results are consistent with a system that is driven by an oscillation in the transmission parameter that is compounded of an oscillation in autumn temperatures (at the resonant frequency of the system, 2.4 years) and, secondarily, by an oscillation in wheat prices (wavelength = 5.3 years, twice that of the epidemics).     

Explaining ethnic polarization over attitudes towards minority rights in Eastern Europe: A multilevel analysis

This paper examines divisions between majority and minority ethnic groups over attitudes towards minority rights in 13 East European societies. Using national sample surveys and multilevel models, we test the effectiveness of competing explanations of ethnic polarization in attitudes towards minority rights, as well as regional and cross-national differences in levels of polarization. We find that, at the individual level, indicators of ‘social distance’ (inter-marriage and social interaction) account most effectively for the extent of ethnic polarization. However, regional and cross-national variations in polarization between majority and minority groups are explained most effectively by cultural (linguistic and religious) differences. These findings accord with research in the West, indicating the importance of cultural differences as a source of ethnic polarization, while offering little support for theories focusing on economic and structural factors or the size of minority groups. They also suggest the likely sources of difficulties for democratic consolidation in ethnically divided post-communist societies.     

郭店楚简《成之》等篇杂志

《郭店楚墓竹简》自从1998年问世后,一直引起中国内外学者的关注,成为研究先秦文字、历史、思想等领域的热门对象。然由于此批竹简的复杂性,再加上研究时间不长,因而尚有许多基本问题有待解决,而这些问题又是与竹简内容的正确理解息息相关的。如果郭店楚简几篇儒家逸书中的部分问题能够解决,便能够对其思想内涵及历史意义达到更进一步的认识。对《成之》篇作两处简序上的调整及对某些字提出新的读法后,便突显出了其中“恒”、“疾”、“终”的进阶概念,关于圣人对善道之“不拾”观念也可以有更深的理解。另外,对《唐虞之道》作简序调整,对《六德》中“多”字给新的解释,涉及问题虽小,但给先秦思想史研究带来的意义不可低估。     

Risk Homeostasis Theory and Traffic Accident Data

The risk homeostasis theory posits, in essence, that a control mechanism analogous to the thermal homeostatic system in warm-blooded animals tends to keep risk per unit time constant, and, as a consequence, the number of traffic accidents per unit time of driving also tends to remain constant, essentially independent of changes in the traffic safety system. It is the purpose of the present research to examine the validity of this claim using a wide variety of traffic accident data. All the data examined are found to be incompatible with the risk homeostasis theory. The only specific field accident data offered in the literature to support the risk homeostasis theory are found to, in fact, refute the theory. The accident data provide evidence that a rich variety of user responses occur. While it is possible for users to collectively respond in such a way that safety benefits are completely cancelled, such a response is not particularly common; it is certainly not universally occurring, as suggested by the risk homeostasis theory. It is concluded that the risk homeostasis theory should be rejected because there is no convincing evidence supporting it and much evidence refuting it.     

Re-visioning nurses' punitive attitudes within forensic psychiatric and correctional nursing: the significance of ethical sophistication

1. Development is an essential lifelong process if we are to compassionately care for patients in forensic and correctional nursing. 2. Many of us are blocked in our ability to understand and to care; we will need to grow to meet the challenges and to bear the shocks of forensic and correctional nursing. 3. Concepts that correspond to Kegan's levels of consciousness imply a progression from punitive attitudes toward more positive attitudes.     

Rehabilitation outlooks for rural Louisiana: educational developments,economic trends,and global perspectives

The objective of this article is to examine current medical, economic, and social trends affecting the provision of rehabilitation services for rural citizens with disabilities. While the population of interest is citizens of Louisiana, the concepts are applicable across all geographic boundaries. The article is a review of clinical practice, job placement alternatives, economic trends, and assessment of process applications. It is concluded numerous steps may be taken to enhance the availability and quality of services provided for rural citizens with disabilities: greater statistical inquiry into rural disability trends, increased incorporation of the Internet into all aspects of rural economic and educational developments, further development of distance learning, promotion of sensitivities towards rural cultures, and continued recruitment of rural allied and vocational rehabilitation professionals.     

Estimating Fatality Reductions from Increased Safety Belt Use

Fatality reductions from increases in safety belt use are estimated taking into account that drivers who change from being nonusers to being users have lower accident involvement rates than the remaining nonusers, a process referred to as "selective recruitment." Analytical functions are derived which express expected fatality reductions in terms of changes in safety belt use rates from an initial rate. The function parameters are determined by requiring that computed average crash rates for nonusers be 53% higher than the rates for users, a recently determined empirical value. These functions show that, depending on the initial use rate and use rate increase, selective recruitment may increase or decrease expected fatality reductions. However, effects are relatively small, in no case exceeding +/- 5.3%.