Optimum take-off angle in the long jump

In this study, we found that the optimum take-off angle for a long jumper may be predicted by combining the equation for the range of a projectile in free flight with the measured relations between take-off speed, take-off height and take-off angle for the athlete. The prediction method was evaluated using video measurements of three experienced male long jumpers who performed maximum-effort jumps over a wide range of take-off angles. To produce low take-off angles the athletes used a long and fast run-up, whereas higher take-off angles were produced using a progressively shorter and slower run-up. For all three athletes, the take-off speed decreased and the take-off height increased as the athlete jumped with a higher take-off angle. The calculated optimum take-off angles were in good agreement with the athletes' competition take-off angles.     

Multitrait-multimethod investigation of a novel body image measurement technique

A multitrait-multimethod (MTMM) matrix was used to evaluate validity evidence for a digital image manipulation (DIM) body image measurement technique in young women. One hundred one young women completed the DIM procedure and the Thompson and Gray (1995) Contour Drawing Rating Scale to measure self-ideal discrepancy and size perception accuracy components of body image. Seven-day test-retest reliability was acceptable (R = .81-.95). Convergent validity for self-ideal discrepancy was higher (r = .74) than the corresponding heterotrait, monomethod coefficients (r = .46, r = .23) and heterotrait-heteromethod coefficients (r = .18, r = .12). However, the convergent validity coefficient for size perception accuracy was r = .12. The pattern of correlations in the MTMM matrix met the criteria of Campbell and Fiske (1959) for validity of these procedures to measure self-ideal discrepancy but not size perception accuracy. The DIM procedure addresses some of the criticisms associated with figure-rating scales, such as unrepresentativeness of the figures, scale coarseness, and restriction of range in responses. DIM, therefore, represents a realistic, valid alternative to figure-rating scales for measuring self-ideal discrepancy.     

Explaining common variance shared by early numeracy and literacy

How can be explained that early literacy and numeracy share variance? We specifically tested whether the correlation between four early literacy skills (rhyming, letter knowledge, emergent writing, and orthographic knowledge) and simple sums (non-symbolic and story condition) reduced after taking into account preschool attention control, short-term memory, speed of processing, visual-spatial skills, vocabulary, and shared book reading. 228 Dutch native preschoolers (mean age 54.25; SD = 2.12 months) participated. The results revealed that 1) all literacy skills were related to sums (non-symbolic and story condition), 2) rhyming was the strongest predictor of non-symbolic sums, and letter knowledge of sums in story context, 3) visual-spatial skills explained part of the shared variance in the non-symbolic condition and visualspatial skills, vocabulary and short-term memory explained part of the shared variance in sums in story context. Implications for the preschool curriculum and early interventions are discussed.     

The Experiential Consultation Training Model

The Experiential Consultation Training Model (ECTM) provides students an opportunity to develop and practice consultation skills through real‐life experiences in actual professional settings. The authors present the structure, process, and evaluation methods of the ECTM and discuss practical applications for counselor education.     

The Accuracy and Consistency of a Series of IRT True Score Equatings

This study investigates a sequence of item response theory (IRT) true score equatings based on various scale transformation approaches and evaluates equating accuracy and consistency over time. The results show that the biases and sample variances for the IRT true score equating (both direct and indirect) are quite small (except for the mean/sigma method). The biases and sample variances for the equating functions based on the characteristic curve methods and concurrent calibrations for adjacent forms are smaller than the biases and variances for the equating functions based on the moment methods. In addition, the IRT true score equating is also compared to the chained equipercentile equating, and we observe that the sample variances for the chained equipercentile equating are much smaller than the variances for the IRT true score equating with an exception at the low scores.     

Inferring cross sections of 3D objects: A new spatial thinking test

A new spatial ability test was administered online to 223 undergraduate students enrolled in introductory science courses. The 30-item multiple choice test measures individual differences in ability to identify the two-dimensional cross section of a three-dimensional geometric solid, a skill that has been identified as important in science, technology, engineering and mathematics (STEM) fields. Bivariate and partial correlations suggest that the test measures a skill that is distinct from three-dimensional mental rotation and change in view perspective. Test items varied along two scales: complexity of the geometric solid to be sliced and orientation of the cutting plane. Internal reliability of both the overall test and its subscales was satisfactory. Performance was higher on figures cut by orthogonal, rather than oblique, planes. Patterns of performance across more and less complex items, and patterns of sex differences on these items, suggest that items on the test are differentially amenable to imagistic and analytic strategies, with males outperforming females on items that are less amenable to analytic strategies. The test shows promise for online administration and for adaptation to younger populations.     

Differences in achievement not in intelligence in the north and south of Italy: Comments on ,

Lynn (2010a, 2010b) argued that individuals from south Italy have a lower IQ than individuals from north Italy, and that these differences in IQ are at the basis of north–south gap in income, education, infant mortality, stature, and literacy. In the present paper, we discuss several theoretical and methodological aspects which we regard as flaws of Lynn's studies. Moreover, we report scores of southern Italian children on Raven's Progressive Matrices and a north–south comparison for the PASS theory of intelligence as measured by the Cognitive Assessment System (Taddei & Naglieri, 2006). Both results reveal similar levels of performance of northern and southern Italian children in fluid intelligence and PASS (Planning, Attention, Simultaneous, and Successive) cognitive abilities.     

Predictors of Familial Acculturative Stress in Asian American College Students

The authors examined the predictors of familial acculturative stress in 85 Asian American college students. Participants were primarily 1st‐ and 2nd‐generation U.S. citizens. Results showed that perceived acculturative family conflict and family intragroup marginalization were related to higher levels of familial acculturative stress for participants. Family intragroup marginalization accounted for a statistically significant proportion of the variance in familial acculturative stress after all variables were controlled. The findings emphasize the need to recognize culture‐specific stressors of college students. Implications for college counselors are discussed.     

Two-parameter characterization of low cycle, hysteretic fatigue data

The aim of this research is to characterize the development of fatigue damage by means of stress-strain hysteresis. Experiments were conducted on 14 specimens made of cold-finished unannealed AISI 1018 steel. Results demonstrate that the mechanical hysteresis loop areas, when plotted as a function of the number of loading cycles, show significant variations and demonstrate the three principal stages concerning the progress of the fatigue failure--initial accommodation, accretion of damage and terminal failure. These three stages of fatigue are marked by the transitions at cycles N2 and N3. Experimental results show that although fatigue life Nf ranges from 2644 cycles to 108 992 cycles, the ratios of N2/Nf and N3/Nf tend to be stable： N2/Nf=I 0.7%, N3/Nf=91.3%.