Repeated retrieval enhances long-term retention, and spaced repetition also enhances retention. A question with practical and theoretical significance is whether there are particular schedules of spaced retrieval (e.g., gradually expanding the interval between tests) that produce the best learning. In the present experiment, subjects studied and were tested on items until they could recall each...

Abstract. Assuming the Riemann hypothesis, we investigate the distribution of gaps between the zeros of ξ(s). We prove that a positive proportion of gaps are less than 0.796 times the average spacing and, in the other direction, a positive proportion of gaps are greater than 1.18 times the average spacing. We also exhibit the existence of infinitely many normalized gaps smaller (larger) than 0....

A study has been made of the distribution and spacing of implantation sites in the uterus of the rat at the 5th day of pregnancy. It has been shown that, whereas the implantation sites along the horns are distributed in an entirely random manner, the distances between the sites are significantly non-random. These results are similar to those previously described for the rabbit and the mouse, an...

BACKGROUND Several recent studies have revealed that words presented with a small increase in interletter spacing are identified faster than words presented with the default interletter spacing (i.e., w a t e r faster than water). Modeling work has shown that this advantage occurs at an early encoding level. Given the implications of this finding for the ease of reading in the new digital era, ...

Recent accounts of the spacing effect have proposed molecular explanations that explain spacing over short, but not long timescales. In the first half of this paper, we review research on the spacing effect that has employed spaces of 24 h or more across skill-related tasks, language-related tasks and generalization for adults and children. Throughout this review, we distinguish between learnin...

By balancing the spacing effect against the effects of recency and frequency, this paper explains how practice may be scheduled to maximize learning and retention. In an experiment, an optimized condition using an algorithm determined with this method was compared with other conditions. The optimized condition showed significant benefits with large effect sizes for both improved recall and reca...

Previous studies suggest that access to modern contraceptives can reduce breast-feeding rates because women who had been using breast-feeding to avoid pregnancy substitute away from it. This article shows that contraceptive use can also have a positive effect on breast-feeding. A mother often weans a child if she becomes pregnant again, which can occur sooner than desired if she lacks access to...

Key planting factors that influence corn stand establishment includes uniform depth and spacing of seed, correct seed population and optimizing the soil environment for rapid germination and uniform emergence. Other variables affecting stand establishment are seedbed quality (including soil moisture and temperature), seed quality and planter speed. Differences among fields for stand establishme...