The Adoption of the Compact Disk Player: An Event History Analysis for the Netherlands

The compact disk (CD) player was one of the major audio innovations of the 1980s in the Netherlands. For studies of the temporal and social diffusion pattern of the CD player and the compact disks, both cultural and economic theories about innovations and music consumption are available. In this paper, these theories are combined in six working hypotheses concerning earlier adoption. The empirical analysis includes both time-invariant and time-varying variables and consumer characteristics. Event history analysis, the technique used in this article, enables one to incorporate these kinds of variables simultaneously in a dynamic model. Compared with the diffusion models usually employed by means of longitudinal analysis, event history analysis is a significant improvement in studying the development of the CD market in the Netherlands.     

Reliability of power output during rowing changes with ergometer type and race distance

Coaches, sport scientists and researchers assess rowing performance on-water and on a variety of ergometers. Ergometers are frequently used because of the easier assessment environment. However, there is limited information on the ability of rowers to reproduce mean power or time-trial time when using different rowing ergometers (Concept II and RowPerfect) or completing tests over different distances (500 m versus 2000 m races). To test the efficacy of an intervention on a rower's ability to produce power, or to monitor that ability, it is essential to determine a reliable rowing performance test. The per cent standard error of measurement in performance (assessed by mean power and time-trial time) of fifteen national standard rowers was determined for five repeated 500 m and two repeated 2000 m races on a Concept II and RowPerfect ergometer. The per cent standard error of measurement (% SEM) in mean power between 5x500m races, regardless of gender, was 2.8% (95% confidence limits (CL)=2.3 to 3.4%) for the Concept II ergometer and 3.3% (95% CL=2.5 to 3.9%) for the RowPerfect ergometer (n = 15). Over 2000 m the per cent standard error of measurement in mean power was 1.3% (95% CL 0.9 to 2.9%) for the Concept II ergometer and 3.3% (95% CL 2.2 to 7.0%) for the RowPerfect ergometer The results highlight an increase in per cent standard error of the mean during performance races of less than 2000m on the Concept II ergometer, and performance races on the RowPerfect ergometer compared with the Concept II ergometer over 500 m and 2000 m. The most appropriate protocol for testing the influence of an intervention on the ability of a rower to produce power would be 2000 m races on a Concept II ergometer.     

Standing waves in thin plates tensioned by in-plane loads subject to high frequency excitation

The problem investigated is that of the response of thin plates subjected to pure tone or wide band frequency excitation. A point load is applied perpendicular to the plates. In the case of isotropic or orthotropic plates excited at high frequencies ring shaped standing wave patterns are observed. No classical explanation exists covering this phenomenon. The present analysis indicates that there are two waves radiating from the excitation point with the same frequency, but at different speeds. One wave, a bending wave, is separated from the other one, a membrane wave.     

What makes a landmark effective? Sex differences in a navigation task

In Experiment 1, two groups of female rats were trained in a triangular pool to find a hidden platform whose location was defined in terms of a single a landmark, a cylinder outside the pool. For one group, the landmark had only a single pattern (i.e., it looked the same when approached from any direction), while for the other, the landmark contained four different patterns (i.e., it looked different when approached from different directions). The first group learned to swim to the platform more rapidly than the second. Experiment 2 confirmed this difference when female rats were trained in a circular pool but found that male rats learned equally rapidly (and as rapidly as females trained with the single-pattern landmark) with both landmarks. This second finding was confirmed in Experiment 3. Finally, in Experiment 4a and 4b, male and female rats were trained either with the same, single-pattern landmark on all trials or with a different landmark each day. Males learned equally rapidly (and as rapidly as females trained with the unchanged landmark) whether the landmark changed or not. We conclude that male and female rats learn rather different things about the landmark that signals the location of the platform.     

The Personal-Emotional Social Adjustment of English-Language Learners to a Community College

ABSTRACT

This study investigated the effects of locus of control and other predictors on personal-emotional and social adjustment to community college in English-language-learner students. Results indicated that locus of control was significantly associated with both social adjustment and personal-emotional adjustment. Students with more external locus of control showed better adjustment to college. Stress and being first in the family to attend college significantly predicted personal-emotional adjustment, while having precollege friends attending the same college was significantly related to social adjustment. Implications for research and service programs are discussed.     

Publication Services at the University Library Graz: A New Venture,a New Role

ABSTRACT

Establishing Publication Services in the library at the University of Graz did more than broaden the service portfolio of the library. A convergence of expertise at the library, needs of researchers at the university, and ongoing changes in scholarly communication also contributed to the evolution of the library's role and profile. The new services offer first-level support for matters pertaining to scholarly publishing and communications. Furthermore, Publication Services has developed into a knowledge sharing platform, extending beyond the library to other administrative departments and creating a community of practice.     

Stability of Intelligence from Preschool to Adolescence: The Influence of Social and Family Risk Factors

Intelligence scores of children in a longitudinal study were assessed at 4 and 13 years and related to social and family risk factors. A multiple environmental risk score was calculated for each child by counting the number of high-risk conditions from 10 risk factors: mother's behavior, mother's developmental beliefs, mother's anxiety, mother's mental health, mother's educational attainment, family social support, family size, major stressful life events, occupation of head of household, and disadvantaged minority status. Multiple risk scores explained one-third to one-half of IQ variance at 4 and 13 years. The stability between 4- and 13-year environmental risk scores ( r = .77) was not less than the stability between 4- and 13-year IQ scores ( r = .72). Effects remained after SES and race, or maternal IQ, were partialled; multiple risk was important in longitudinal prediction, even after prior measurement of child IQ was accounted for; the pattern of risk was less important than the total amount of risk present in the child's context.     

Initiations of social interactions by young hearing impaired preschoolers

This study examined strategies for initiating social interactions with peers, among 4 children with hearing impairment, aged 33 to 36 months, attending a special early education center or a regular kindergarten. The study investigated initiation type (related to partner's hearing status) and rates of initiation success/failure vis-a-vis hearing and deaf partners. Results revealed (a) more initiations in the regular program than in the special program; (b) in the special program, much more successful initiations toward children with hearing impairment than toward hearing children; (c) vocalization as the most frequent strategy used with both hearing and hearing-impaired partners; and (d) referential decisions about their initiations even among young children with hearing impairment (made by changing frequencies of various strategies according to partner's hearing status). The discussion addressed implications regarding integration of children with hearing impairment into regular educational settings.