Conventional pressure sensitive adhesives (PSAs) are fabricated from soft viscoelastic materials that satisfy Dahlquist's criterion for tack with a Young's modulus (E) of 100 kPa or less at room temperature and 1 Hz. In contrast, the adhesive on the toes of geckos is made of beta-keratin, a stiff material with E at least four orders of magnitude greater than the upper limit of Dahlquist's crite...

Linear mixed-effects models are widely used in applications to analyze clustered, hierarchical, and longitudinal data. Model selection linear mixed is more challenging than that of as the parameter vector a model includes both fixed effects variance component parameters. When selecting components random effects, must be non-negative parameters may lie on boundary space. Therefore, classical met...