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The lasso penalizes a least squares regression by the sum of the absolute values (L 1-norm) of the coefficients. The form of this penalty encourages sparse solutions (with many coefficients equal to 0). We propose the 'fused lasso', a generalization that is designed for problems with features that can be ordered in some meaningful way. The fused lasso(More)
Mps1 is a dual specificity protein kinase that is essential for the bipolar attachment of chromosomes to the mitotic spindle and for maintaining the spindle assembly checkpoint until all chromosomes are properly attached. Mps1 is expressed at high levels during mitosis and is abundantly expressed in cancer cells. Disruption of Mps1 function induces(More)
The formation of epicormic sprouts on the boles of trees is a phenomenon that has, until recently, been poorly understood. Renewed interest in the topic in the last two decades has led to significant advances in our knowledge of the subject, especially in regard to bud anatomy, morphology and ontogeny. There exists, however, no comprehensive synthesis of(More)
We perform an algebraic analysis of a generalization of the augmented Lagrangian method for solution of saddle point linear systems. It is shown that in cases where the (1,1) block is singular, specifically semidefinite, a low-rank perturbation that minimizes the condition number of the perturbed matrix while maintaining sparsity is an effective approach.(More)
Numerical tests are used to validate a practical estimate for the optimal backward errors of linear least squares problems. This solves a thirty-year-old problem suggested by Stewart and Wilkinson. " A great deal of thought, both by myself and by J. H. Wilkinson, has not solved this problem, and I therefore pass it on to you: find easily computable(More)
When a tree dies, it continues to play an important ecological role within forests. Coarse woody debris (CWD), including standing deadwood (SDW) and downed deadwood (DDW), is an important functional component of forest ecosystems, particularly for many dispersal-limited saproxylic taxa and for metapopulation dynamics across landscapes. Processes, such as(More)