The relation between positivity of principal minors, sign symmetry and stability of matrices is studied. It is shown that for sign symmetric matrices, having positive principal minors is equivalent to stability, to D-stability, and to having a positive scaling into a stable matrix. The relation between spectra of matrices some of whose powers have positive principal minors and matrices whose co...

The UT Austin Villa 2003 simulated online soccer coach was a first time entry in the RoboCup Coach Competition. In developing the coach, the main research focus was placed on treating advice-giving as a learning problem. The coach learns to predict agent behavior from past observations and automatically generates advice to improve its team’s performance. Using this approach, the UT Austin Villa...

At a child care center, 18-month-old Hannah is clinging to her mother and crying as they enter. Her mother pulls Hannah’s hands from her arm, saying, “Don’t be such a crybaby and go play.” In a pediatrician’s waiting room, two-year-old Carlos climbs dangerously high on the furniture. He throws a toy at his mother when she calls his name. His mother laughs nervously and says quietly, “I don’t kn...

The k-th power H of a graph H is obtained from H by adding new edges between every two distinct vertices having distance at most k in H . Lau [Bipartite roots of graphs, ACM Transactions on Algorithms 2 (2006) 178–208] conjectured that recognizing k-th powers of some graph is NP-complete for all fixed k ≥ 2 and recognizing k-th powers of a bipartite graph is NP-complete for all fixed k ≥ 3. We ...

PURPOSE To determine whether rotational stability is improved with the longer Staar toric intraocular lens (IOL). SETTING A private practice, Los Altos, California, USA. METHODS Staar Surgical manufactures toric plate-haptic IOLs under +24.0 diopters (D) in 2 lengths. Fifty consecutive eyes requiring toric IOL spherical powers less than +24.0 D received the longer toric IOL (TL; 11.2 mm) us...

Cyclic nucleotide-dependent protein phosphorylation plays a central role in neuronal signal transduction. Neurotransmitter-elicited increases in cAMP/cGMP brought about by activation of adenylyl and guanylyl cyclases are downregulated by multiple phosphodiesterase (PDE) enzymes. In brain, the calmodulin (CaM)-dependent isozymes are the major degradative activities and represent a unique point o...