Defining emotional disturbance public policy and research

The legal definition of “emotional disturbance” proposed by the Federal Government under PL 94–142 is Bower's 1957 definition with some modifications. The modifications do serious damage to the integrity of the research and conceptual base from which the definition is drawn. The difficulties inherent in a definition of this type of handicapped are delineated. It is suggested that where policy makers and researchers join together, such relationships are best enhanced when each respects the assumptions and concepts of the other.     

Survey of medical literature borrowed from the national lending library for science and technology

This paper reports the results of a four-week questionnaire survey carried out at the National Lending Library (N.L.L.), Great Britian, to discover which types of organizations were the principal users of medical literature, what types of literature were used, and which were the main sources of references to medical publications. Industrial organizations and universities accounted for the majority (62 percent) of the loans, most of which were English-language periodicals published since 1960. For the whole sample, citation lists in periodical articles were the principal sources of references, although for literature published in the last fifteen months, abstracting and indexing journals were the main sources. Of the latter, Index Medicus proved to be the most fruitful source of references. By asking whether the item requested was really useful to their work, a measure of the reliability of the different sources of references was obtained.Appendixes include the questionnaire, a list of the most frequently borrowed journals, and a list of abstracting and indexing journals used as sources of references.     

The development of place value concepts: Approximation before principles

Place value concepts were measured longitudinally from kindergarten (2017) to first grade (2018) in a diverse sample (n = 279; M_age = 5.76 years, SD = 0.55; 135 females; 41% Black, 38% White, 8% Asian, 12% Latino). Children completed three syntactic tasks that required an explicit understanding of base-10 symbols and three approximate tasks that could be completed without this explicit understanding. Approximate performance was significantly better in both age groups. A factor analysis confirmed that syntactic and approximate tasks tapped separate latent variables in kindergarten, but not in first grade. Path analyses indicated that only kindergarten approximate performance predicted overall first-grade place value understanding. These findings suggest that explicit understanding of base-10 principles develops from implicit, partial knowledge of multidigit numbers.     

The relationship between lower body stiffness and injury incidence in female netballers

The aim of this study was to provide contemporary information on injury rates in an elite and sub-elite netball population and to explore the relationship between lower body stiffness and lower body injuries. One elite and two sub-elite teams of female netballers (n = 29) performed the vertical hop test to assess active lower body stiffness (K_vert) and myometry to assess quasi-static stiffness. Lower body injuries were monitored via self-reporting and liaison with physiotherapists. Twelve lower body non-contact injuries were sustained by 10 players, equating to 11.29 lower body injuries per 1,000 exposure hours. The most commonly injured sites were the calf (33%) and ankle (25%). No significant differences between K_vert of injured and non-injured players were reported, however, injured elite players recorded significantly higher season mean quasi-static stiffness in the soleus (p = 0.037) and Achilles (p = 0.004) than non-injured elite players. Elite and sub-elite netball players recorded a higher injury incidence than previous reports of injuries in recreational netballers. Within the constraints of the study, relatively high stiffness of the soleus and Achilles appears to be related to lower body non-contact injury incidence in female netballers, particularly at the elite level. These results provide a basis for development of injury prevention strategies.     

String tension effects on tennis ball rebound speed and accuracy during playing conditions

The primary aim of this study was to determine whether variations in rebound speed and accuracy of a tennis ball could be detected during game-simulated conditions when using three rackets strung with three string tensions. Tennis balls were projected from a ball machine towards participants who attempted to stroke the ball cross-court into the opposing singles court. The rebound speed of each impact was measured using a radar gun located behind the baseline of the court. An observer also recorded the number of balls landing in, long, wide and in the net. It was found that rebound speeds for males (110.1?±?10.2?km?·?h^?1; mean?±?s) were slightly higher than those of females (103.6?±?8.6?km?·?h^?1; P?<?0.05) and that low string tensions (180?N) produced greater rebound speeds (108.1?±?9.9?km?·?h^?1) than high string tensions (280?N, 105.3?±?9.6?km?·?h^?1; P?<?0.05). This finding is in line with laboratory results and theoretical predictions of other researchers. With respect to accuracy, the type of error made was significantly influenced by the string tension (P?<?0.05). This was particularly evident when considering whether the ball travelled long or landed in the net. High string tension was more likely to result in a net error, whereas low string tension was more likely to result in the ball travelling long. It was concluded that both gender and the string tension influence the speed and accuracy of the tennis ball.