Many barchan dune corridors appear to contain dunes of stable size and spacing [1], and dune fields often exhibit regular patterns [2, 3] with apparent characteristic size and spacing (figure 1). It is still an open question as to what sets this characteristic scaling – local conditions such as topography or sand supply, or common dynamic processes such as those relating to saltation. Additiona...

The spacing effect describes the robust finding that long-term learning is promoted when learning events are spaced out in time rather than presented in immediate succession. Studies of the spacing effect have focused on memory processes rather than for other types of learning, such as the acquisition and generalization of new concepts. In this study, early elementary school children (5- to 7-y...

Two experiments address the degree to which item memory-the ability to remember that a word has been presented-is dissociable from source memory, or the ability to remember the context of that word's presentation. Spacing (as opposed to massing) an item's two presentations leads young adults to endorse that item more often when they are instructed to recognize it and to reject it more often whe...

A two-dimensional numerical study of flow across rows of identical square cylinders arranged in staggered fashion is carried out. This study will unreveal complex flow physics depending upon the Reynolds number (Re) and gap spacing (g) between the cylinders. The combined effect of Reynolds number and gap spacing on the flow physics around staggered rows of cylinders are numerically studied for ...

Expertise in face processing takes many years to develop. To determine the contribution of different face-processing skills to this slow development, we altered a single face so as to create sets of faces designed to measure featural, configural, and contour processing. Within each set, faces differed only in the shape of the eyes and mouth (featural set), only in the spacing of the eyes and mo...

3 experiments varying the interval between 2 presentations of paired associates were reported. Other pairs filled the spacing and retention intervals. Pairs consisting of a word and a number as well as pairs consisting of 2 words showed a superiority at 8 sec. and longer retention intervals when presentations were spaced. Increasing the spacing interval beyond 8 sec. did not increase recall, wh...

A sequence of rainbows is produced in light scattering by a particle of high symmetry in the short-wavelength limit, and a supernumerary interference pattern occurs to one side of each rainbow. Using both a ray-tracing procedure and the Debye-series decomposition of first-order perturbation wave theory, I examine the spacing of the supernumerary maxima and minima as a function of the cylinder r...

In dealing with a dynamic world, people have the ability to maintain selective attention on a subset of moving objects in the environment. Performance in such multiple-object tracking is limited by three primary factors-the number of objects that one can track, the speed at which one can track them, and how close together they can be. We argue that this last limit, of object spacing, is the roo...

Tandemly repeated DNA sequences generated from single synthetic oligonucleotide monomers are useful for many purposes. With conventional ligation procedures low yields and random orientation of oligomers makes cloning of defined repeated sequences difficult. We solved these problems using 2 bp overhangs to direct orientation and random incorporation of linkers containing restriction sites durin...

Short birth spacing continues to be a problem in Uganda and Zimbabwe, resulting in negative infant, child, and maternal health outcomes. This study investigates community-level influences on birth spacing outcomes among women aged 15-49 in Uganda and Zimbabwe, using Demographic and Health Surveys conducted in 2011 (Uganda) and 2010-2011 (Zimbabwe). Women living in communities with higher mean m...