Component-wise gradient boosting and false discovery control in survival analysis with high-dimensional covariates.

MOTIVATION: Technological advances that allow routine identification of high-dimensional risk factors have led to high demand for statistical techniques that enable full utilization of these rich sources of information for genetics studies. Variable selection for censored outcome data as well as control of false discoveries (i.e. inclusion of irrelevant variables) in the presence of high-dimensional predictors present serious challenges. This article develops a computationally feasible method based on boosting and stability selection. Specifically, we modified the component-wise gradient boosting to improve the computational feasibility and introduced random permutation in stability selection for controlling false discoveries. RESULTS: We have proposed a high-dimensional variable selection method by incorporating stability selection to control false discovery. Comparisons between the proposed method and the commonly used univariate and Lasso approaches for variable selection reveal that the proposed method yields fewer false discoveries. The proposed method is applied to study the associations of 2339 common single-nucleotide polymorphisms (SNPs) with overall survival among cutaneous melanoma (CM) patients. The results have confirmed that BRCA2 pathway SNPs are likely to be associated with overall survival, as reported by previous literature. Moreover, we have identified several new Fanconi anemia (FA) pathway SNPs that are likely to modulate survival of CM patients. AVAILABILITY AND IMPLEMENTATION: The related source code and documents are freely available at https://sites.google.com/site/bestumich/issues. CONTACT: yili@umich.edu.

Effects of Mindful Acceptance and Reappraisal Training on Maladaptive Beliefs About Rumination

© 2016, Springer Science+Business Media New York.The present study examined the relative effects of mindful acceptance and reappraisal on metacognitive attitudes and beliefs in relation to rumination and negative experiences. A small but growing literature has compared the effects of these strategies on immediate emotional experience, but little work has examined the broader, metacognitive impact of these strategies, such as maladaptive beliefs about rumination. One hundred and twenty-nine participants who reported elevated symptoms of depression were randomly assigned to receive brief training in mindful acceptance, reappraisal, or no training prior to undergoing an autobiographical sad mood induction. Participants rated their beliefs in relation to rumination and negative experiences before and after instructions to engage in mood regulation. Results showed that relative to reappraisal or no training, training in mindful acceptance resulted in greater decreases in maladaptive beliefs about rumination. The study suggests that training in mindful acceptance promotes beneficial changes in metacognitive attitudes and beliefs relevant to depression, and contributes to a greater understanding of the mechanisms through which mindfulness-based interventions lead to positive outcomes.