Selected schedules of reinforcement in the black-tailed prairie dog (Cynomys ludovicianus)

Wild black-tailed prairie dogs were run on FR, FI, VR, and VI schedules for Noyes pellet reinforcement. Cumulative barpress responses, postreinforcement pause lengths, and responses per second were recorded. The highest response rates occurred in the VR schedules, with the lowest response rates coming in the FI schedules. Fixed-ratio schedules had the longest postreinforcement pauses, VI schedules had the shortest. At the upper levels of the fixed-ratio schedules (FR 90–100), the animals ceased to respond consistently. Generally, data from prairie dogs were consistent with data reported in studies from other mammalian species.     

Are the Factors Affecting Dropout Behavior Related to Initial Enrollment Intensity for College Undergraduates?

We use data from the 1990/1994 Beginning Post-Secondary Survey to determine whether the factors associated with long-term attrition from higher education differ for students who initially enrolled part-time as compared to for students who initially enrolled full-time. Using a two-stage sequential decision model to analyze the initial enrollment intensity decision jointly with attrition, we find no evidence of correlation in the unobservables that necessitates joint estimation, but substantial evidence that the factors associated with attrition differ by initial enrollment status. The timing of initial enrollment, academic performance, parental education, household characteristics, and economic factors had a substantially greater impact on those initially enrolled full-time, while racial and ethnic characteristics had a greater impact on those initially enrolled part-time. The results of our study suggest that separate specifications are necessary to identify at-risk full-time as compared with at-risk part-time students. The data employed here were generated while working under a grant supported in part by the Association for Institutional Research, the National Center for Education Statistics, and the National Science Foundation under the Association for Institutional Research 1999 Improving Institutional Research in Post-secondary Educational Institutions Grant Program. The Spencer Foundation Small Grants program provided funding for the analysis. Leslie Stratton gratefully acknowledges additional support from a 2001 Faculty Excellence Award from Virginia Commonwealth University. Referees from the 2005 Southern Economic Association meetings and from Research in Higher Education provided very helpful comments. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the Spencer Foundation, the Association for Institutional Research, the National Center for Education Statistics, or the National Science Foundation.     

Child Sleep and Socioeconomic Context in the Development of Cognitive Abilities in Early Childhood

Despite a robust literature examining the association between sleep problems and cognitive abilities in childhood, little is known about this association in toddlerhood, a period of rapid cognitive development. The present study examined the association between various sleep problems, using actigraphy, and performance on a standardized test of cognitive abilities, longitudinally across three ages (30, 36, and 42 months) in a large sample of toddlers (N = 493). Results revealed a between-subject effect in which the children who had more delayed sleep schedules on average also showed poorer cognitive abilities on average but did not support a within-subjects effect. Results also showed that delayed sleep explains part of the association between family socioeconomic context and child cognitive abilities.     

A systematic approach to the design of secondary school lessons in Guyana

Selected physics and geography classes in Guyanan secondary schools received four different instructional treatments. Three experimental groups received (A) a systematically designed curriculum unit implemented by the designer of the unit (B) the same unit implemented by another teacher and (C) a lesson utilising the aims and objectives defined in the curriculum unit. A fourth (control) group received the conventional lesson for this aspect of the curriculum. Pre- and post-test data revealed significant learning gains in experimental groups. The implications of these results are considered for curriculum development and the training of teachers in Guyana.     

Rates of invention: international patent comparisons

The increased patenting activity of foreign nationals in the United States has been a source of recent concern, and the fear has been expressed that the US is becoming relatively less technologically inventive. This paper investigates some possible causes of the increased foreign patenting activity and also briefly examines the determinants of patent filings by a country's own residents. The countries covered include: Canada, France, West Germany, Japan, the Netherlands, Sweden, Switzerland, the United Kingdom, and the United States.Based on data on patent applications filed and some preliminary regression analysis, the paper finds that the rising foreign patenting activity in the US probably does not reflect increased foreign inventiveness vis-à-vis the US. However, foreign innovativeness may be increasing relative to the US. Over the period 1963 – 1974, the domestic patent base, measured by the number of patent applications filed by nationals in their home countries, has shown little change in any country except for Japan. Rather, multiple patent applications and a greater propensity to patent abroad, induced by the possibilities of exporting, appear to be the sources of the increase in foreign patent applications in the US and also in Japan.     

Developments in electronography for astronomical research

Astronomers are always interested in detecting and observing the faintest, most distant objects in the Universe. Electronography has the advantages over photography where it counts most—when observing the faintest objects. The technical problems involved in the development of electronography are here reviewed, and recent advances and observations with the RGO camera are described.     

Notes on writing subjects of action research

In this article, the author playfully represents his role as reader and interpreter of an article sent to him for review by editors of the journal Educational Action Research. By representing the specificity of his reader responses, the author shows how literacy practices function to create the identities of readers and writers. It is argued that a post-structural view of reading and interpretation helps those engaged in action research projects to understand that knowledge and identities are co–specified. Reports of action research, then, are not merely reports of what is learned through shared inquiry; they also reveal traces of how the subjects involved in action research are affected by their work.