As the articles in this issue attest, U-shaped curves in development have stimulated a wide spectrum of research across disparate task domains and age groups and have provoked a variety of ideas about their origins and theoretical significance. In our view, the ubiquity of the general pattern suggests that U-shaped curves can arise from multiple factors, and that the various viewpoints represen...

Nanocomposites made of Carbon Nanotube (CNT) bundles have attracted researchers’ attention due to their unusual properties such as: light weight, flexibility and stiffness.  In this paper, the effects of straight and rope-shaped bundles on nanocomposite effective mechanical properties are investigated.  First, FEA models are created consisting of CNTs with different shapes of straight and rope-...

We consider the problem of recognizing star-polygons under staircase visibility (s-visibility). We show that the s-visibility polygon from a point inside a simple orthogonal polygon of n sides can be computed in O(n) time. When the polygon contains holes the algorithm runs in O(n log n) time, which we prove to be optimal by linear time reduction from sorting. We present an algorithm for computi...

Responsiveness of 1-, 3-, and 5-year-old children and adults to octave-band noises at .4 and 10 kHz was assessed with a go/no-go version of visual reinforcement audiometry (VRA) (Moore, Thompson, & Thompson, 1975) and a two-alternative, forced-choice version (Suzuki & Ogiba, 1961; Trehub, Schneider, & Endman, 1980). Infants performed better on the two-alternative, forced-choice version in quiet...

On the basis of perodic density functional theory (DFT) calculations, we have addressed the geometric structures and electronic properties of water layers on flat and stepped Pb surfaces. In contrast to late d-band metals, on Pb(111) the energy minimum structure does not correspond to an ice-like hexagonal arrangement at a coverage of 2/3, but rather to a distorted structure at a coverage of 1 ...