Sound Localization and Sensitivity to Interaural Time Differences in Human Infants

The role of interaural time differences in infants' sound localization was investigated. One experiment on free-field sound localization corroborated previous findings that the minimum audible angle changes substantially toward the end of the first half year after birth, and 3 experiments explored interaural time discrimination in that age range. The first of these 3 experiments used an adaptive psychophysical procedure, showing that infants responded appropriately in a sound lateralization task that provides a direct measure of interaural time discrimination. The other 2 experiments improved on the psychophysical procedure by taking into account the ceiling level on performance in the task. Infants aged 16, 20, and 28 weeks had thresholds in the range of 50 to 75 microsec, with no apparent age difference. These thresholds were much lower than would be predicted from studies of free-field sound localization, indicating that sensitivity to interaural time differences is not a limiting factor for the precision of sound localization in this age range. Instead, age-related changes in free-field sound localization may reflect the need to integrate across different localization cues and to calibrate the changing values of cues due to head growth.     

Past Endeavors and Future Perspectives for Sport Management Research

While the bulk of research in sport management would primarily stem from masters' and doctoral studies, quality research by sport management scholars is now published regularly in some of the best journals the profession can offer. This research is original and exclusive to the field, however, its findings are not systematically organized. There is a need to put in order what we know and what we don't know about managing sport. This paper presents two inductive analyses of sport management research topics, one for doctoral dissertations and the other for published conference abstracts and journal articles. In an attempt to stimulate discussion about the need to map out completed research in this field and systematically organize findings, the paper also proposes a conceptual model of relevant relationships that can be explored in sport management research.     

Implementation of a project-based molecular biology laboratory emphasizing protein structure-function relationships in a large introductory biology laboratory course

In introductory laboratory courses, many universities are turning from traditional laboratories with predictable outcomes to inquiry-inspired, project-based laboratory curricula. In these labs, students are allowed to design at least some portion of their own experiment and interpret new, undiscovered data. We have redesigned the introductory biology laboratory course at Brandeis University into a semester-long project-based laboratory that emphasizes concepts and contains an element of scientific inquiry. In this laboratory, students perform a site-directed mutagenesis experiment on the gene encoding human γD crystallin, a human eye lens protein implicated in cataracts, and assess the stability of their newly created protein with respect to wild-type crystallin. This laboratory utilizes basic techniques in molecular biology to emphasize the importance of connections between DNA and protein. This project lab has helped engage students in their own learning, has improved students' skills in critical thinking and analysis, and has promoted interest in basic research in biology.     

Digging behavior in 12 taxa of muroid rodents

The digging behavior of 12 taxa of muroid rodents was observed on sand and peat substrates. Overall, significantly more digging was performed on peat than on sand. The percentage of animals of each taxon that dug was found to be positively correlated with both the duration of digging and the number of bouts of digging and negatively correlated with latency to dig. Differences across taxa in the duration of digging were correlated with field observations of the nesting behavior of these taxa; taxa that frequently utilize subterranean nest sites exhibited more digging than those that do not. The motor patterns used in digging are described;Mus musculus was the only species that appeared to exhibit a unique digging pattern. Digging behavior appears to be a pattern that is readily elicited in the laboratory, related to behavior in the field, and appropriated for further laboratory study.     

Technology adoption, training and productivity performance

Advanced technologies are commonly thought to be complementary to skills. Firms that adopt new technologies (for example, computer-aided design and control) and at the same time invest in skills (for example, training in computer literacy and technical skills) are expected to realize greater productivity gains than those that do not. To validate this expectation, this paper first identifies the combinations of technologies and types of training that are commonly undertaken by firms, presumably as part of their strategies to effectively utilize the adopted technologies and to improve their economic performance. This paper then estimates the relationship between these common technology-training combinations and productivity performance. It shows that these combinations are associated with higher productivity.     

Are we wasting our children's time by giving them more homework?

Following an identification strategy that allows us to largely eliminate unobserved student and teacher traits, we examine the effect of homework on math, science, English and history test scores for eighth grade students in the United States. Noting that failure to control for these effects yields selection biases on the estimated effect of homework, we find that math homework has a large and statistically meaningful effect on math test scores throughout our sample. However, additional homework in science, English and history are shown to have little to no impact on their respective test scores.