A model selection approach for the identification of quantitative trait loci in experimental crosses

Summary. We consider the problem of identifying the genetic loci (called quantitative trait loci (QTLs)) contributing to variation in a quantitative trait, with data on an experimental cross. A large number of different statistical approaches to this problem have been described; most make use of multiple tests of hypotheses, and many consider models allowing only a single QTL. We feel that the problem is best viewed as one of model selection. We discuss the use of model selection ideas to identify QTLs in experimental crosses. We focus on a back-cross experiment, with strictly additive QTLs, and concentrate on identifying QTLs, considering the estimation of their effects and precise locations of secondary importance. We present the results of a simulation study to compare the performances of the more prominent methods.     

原住民治理的宪政构架

在如何理解澳大利亚政府的宪政构架上,需要一个观念转变。这个转变的基础,是理解原住民治理的存在及其在澳大利亚政治组织各个层面的实践,以及澳大利亚州的正式制度已暗中接纳各种形式的原住民治理。澳大利亚的联邦主义经验意味着理解这种转变很容易做到。当联邦和州的原住民政策最终和支持它们的治理构架一样强大时,这一转变必定出现。     

A randomized test of a small-group interactive social norms intervention

Social norms interventions are a common approach to addressing the problem of college student drinking. An increasingly popular but not yet well-validated social-norms-based intervention consists of providing normative feedback to students in small groups. OBJECTIVE, PARTICIPANTS, AND METHODS: In this study, the authors used a randomized design to test an interactive form of small-group social norms correction with 502 first-year students during September and October 2001. Because the unit of random assignment was at the level of the classroom, the authors used hierarchical linear modeling to estimate variability. They investigated whether small-group interactive social norms correction could influence alcohol perceptions and behaviors above and beyond a noninteractive social norms education approach. RESULTS: Results indicate that the approach has a fairly substantial influence on student perceptions; however, the findings do not support an influence of interactive small-group social norms correction on measures of alcohol use behaviors. CONCLUSIONS: Given these findings, the use of interactive small-group social norms approach to influence student misperceptions may be considered as a primer for population-level preventive interventions.