Application of the Rasch model to measuring the impact of scientific journals

This paper focuses on a fresh and fair way to determine a ranking of science journals according to the “number of citations-to and articles published,” data used by SCI Journal Citation Reports of ISI to determine journal ranking by “impact factor.” Impact is considered a latent variable defined by a set of items (citations and articles published). The theoretical background is Item Response Theory, which suggests that, if we can understand how each item in a set of items operates with an object, then we can estimate a measure for the object. The Rasch model is the most common formulation of that theory. This technique is here applied to the citations and articles published of 62 medical journals (objects) to provide a Rasch measure for these journals which is compared with the current “impact factor” computation.     

Effects of a combined inversion and plantarflexion surface on knee and hip kinematics during landing

Although landing in a plantarflexion and inversion position is a well-known characteristic of lateral ankle sprains, the associated kinematics of the knee and hip is largely unknown. Therefore, the purpose of this study was to examine the changes in knee and hip kinematics during landings on an altered landing surface of combined plantarflexion and inversion. Participants performed five drop landings from 30 cm onto a trapdoor platform in three different conditions: flat landing surface, 25° inversion, or a combined 25° plantarflexion and 25° inversion. Kinematic data were collected using a seven camera motion capture system. A 2 × 3 (leg × surface) repeated measures ANOVA was used for statistical analysis. The combined surface showed decreased knee and hip flexion range of motion (ROM) and increased knee abduction ROM (p < 0.05). The altered landing surface creates a stiff landing pattern where reductions in sagittal plane motion are transferred to the frontal plane, resulting in increased knee abduction. A stiff landing pattern is frequently related to increased risk of anterior cruciate ligament injury. It may be beneficial for athletes at risk to train for alternate methods of increasing their sagittal plane motion of the knee and hip with active knee or trunk flexion.     

Comparison of starts and turns of national and regional level swimmers by individualized-distance measurements

The aim of this study was to compare the race characteristics of the start and turn segments of national and regional level swimmers. In the study, 100 and 200-m events were analysed during the finals session of the Open Comunidad de Madrid (Spain) tournament. The “individualized-distance” method with two-dimensional direct linear transformation algorithm was used to perform race analyses. National level swimmers obtained faster velocities in all race segments and stroke comparisons, although significant inter-level differences in start velocity were only obtained in half (8 out of 16) of the analysed events. Higher level swimmers also travelled for longer start and turn distances but only in the race segments where the gain of speed was high. This was observed in the turn segments, in the backstroke and butterfly strokes and during the 200-m breaststroke event, but not in any of the freestyle events. Time improvements due to the appropriate extension of the underwater subsections appeared to be critical for the end race result and should be carefully evaluated by the “individualized-distance” method.     

Factorial Validity and Invariance Testing of the Exercise Dependence Scale-Revised in Swedish and Portuguese Exercisers

The present study investigated the factorial validity and factorial invariance of the 21-item Exercise Dependence Scale-Revised using 162 Swedish and 269 Portuguese exercisers. In addition, the prevalence of exercise dependence symptoms and links to exercise behavior, gender, and age in the two samples was also studied. Confirmatory factor analyses demonstrated that the hypothesized 7-factor model made a good fit to data in both samples. Multi-sample analyses supported partial measurement invariance across the samples; only factor loadings involving items 3 and 19 were noninvariant. The “Reduction in Other Activities” and “Lack of Control” factors were the most problematic scales in terms of average variance explained and reliability measures of weighted omega and Cronbach's alpha. In total, 9.2% of the Swedish sample and 5.2% of the Portuguese sample were classified as at risk for exercise dependence. Overall, the results support the factorial validity of the translated Exercise Dependence Scale-Revised in samples outside North-America, although more research is needed.     

The AGTR2 rs11091046 (A>C) polymorphism and power athletic status in top-level Brazilian athletes

The main purpose of this study was to investigate if the rs11091046 (A>C) polymorphism in AGTR2 gene is associated with athletic status in top-level athletes from Brazil. Since the AGTR2 gene is located on the X chromosome, the case-control association study was done separately for women and men. The female cohort was composed of 205 athletes and 241 non-athletes, and the male cohort was composed of 419 athletes and 490 non-athletes. We did not identify an association between the C-allele and the endurance phenotype. However, power athletes had a higher frequency of the A-allele. In women, A/A genotype was overrepresented in international-level power group compared with non-athletes or international-level endurance athletes (23.2% vs. 16.6% or 8.8%, respectively; p < 0.05). In men, the A-allele frequency observed in power athletes or international-level power athletes was statistically different from that observed in non-athletes (51.6% or 57.8% vs. 40.4%; p < 0.009). Furthermore, men sprinters with the A-allele showed significantly faster personal best times for the 100 m than those with the C-allele (10.56 ± 0.32 s vs. 10.93 ± 0.49 s; p < 0.02). In conclusion, it was found that the AGTR2 A-allele is a candidate genetic marker for top-level power athletes.     

Control-based Connection Admission Control and Downlink Congestion Control procedures for satellite networks

This paper focuses on the resource management procedures for a geostationary (GEO) satellite system. The objective of these procedures is the efficient exploitation of the link resources, while assuring the agreed Quality of Service to the traffic entering the satellite network. The main novelties are (i) the integration between Connection Admission Control and Downlink Congestion Control procedures, and (ii) the original adaptation of Kalman filtering theory to cope with these procedures. The proposed solution is validated by simulations.     

Adaptive SMC based on the dynamic containment of the sliding variable

Conventional Sliding Mode Controllers (SMCs) exhibit a robust performance against matched bounded uncertainties and disturbances by containing them under a fixed controller’s effort. Consequently, the controller is commonly found excessive, leading to chattering and straining the actuator. As a solution, the variable-gain SMCs adapt to the instantaneous system requirements, thus attenuating the aforesaid effects and keeping the SMC’s benefits. However, the reported adaptive laws underlying such behavior commonly require arbitrary design considerations and do not consider practical implementation. Unlikely, in this work, a hysteresis-based adaptability law to drive the sliding variable to a boundary layer around zero is proposed. The sliding boundary—hysteresis’ width—will consistently “bounce” over the sliding variable, trying to shrink against it while preserving the sliding mode. This behavior finds its steady-state once the sliding variable and the sliding boundary’s dynamics are synchronized, with no need of subjective or arbitrary adjustments. The close-loop tuning can be derived from the system’s parameters alone, and its steady-state performance can be quantitatively predicted. Furthermore, a method to adjust the sliding surface parameters according to the system’s desired behavior is provided, all in a closed, analytical way. Finally, the physical actuator limits are taken into account and never exceeded, and the discrete nature of the devices normally used for SMC implementation is incorporated throughout. Two examples are studied to portray the proposal’s advantages.     

Influencia de la diferencia de edad interclase en la obtención de calificaciones escolares

RESUMEN

Se plantea la hipótesis de que la variable edad intraclase juega un papel importante en la obtención de calificaciones, por lo que dentro del mismo curso los niños de mayor edad obtendrán puntuaciones más altas. El estudio revisa las calificaciones de 533 alumnos entre párvulos y 8° EGB, divididos por curso en tres grupos: mayores, intermedios y menores, y compara el rendimiento de los alumnos mayores y menores. Con algunas precisiones queda comprobada la hipótesis inicial, sobre todo en la etapa de párvulos a 5° EGB. Por lo tanto, estas diferencias de niños en un mismo curso debidas a la edad deberían tenerse en cuenta a la hora de diseñar programas educativos, establecer criterios de agrupamiento y evaluar el rendimiento escolar. Las calificaciones deben servir de índice de la asimilación de los programas por parte del niño, y carecer de connotaciones competitivas o valorativas de éxito o fracaso. La atención individualizada, aunque inviable debido a las características del sistema educativo, permitiría una enseñanza acorde con el nivel de desarrollo.     

THE IMPLICATIONS OF INTERCULTURAL EDUCATION FOR HIGHER EDUCATION

Studies on intercultural education undertaken by the Council of Europe have highlighted a gap at the level of higher education between transmitted knowledge and the indispensable information needed by individuals living in the pluricultural contexts of contemporary European societies. A task of higher education is to inculcate in teachers an intercultural perspective both for work in schools and for activities in community contexts and perspectives. The intercultural dimension should not simply address itself to a special category of culturally different students, but rather, should address all students so as to sensitize them to the cultural pluralism which surrounds them and to educate them to successfully master it. Certain disciplines have a privileged status with regard to the transmission of useful information for the education of all citizens living in pluricultural societies: history, geography, anthropology, philosophy, psychology, economics, sociology, and law. Several examples of intercultural education programmes offered by higher education institutions are presented in this study (in Portugal, Canada, and France) as well as reference to activities sponsored by the Higher Education and Research Division of the Council of Europe.     

The relationship between approaches to teaching and approaches to studying: a two-level structural equation model for biology achievement in high school

Since the 1970s, a large body of research has reported on the differences between deep and surface approaches to student learning. More recently, however, this metaphor for students’ approaches to learning has been applied to the practice of teaching. Studies at the university level have identified two approaches to teaching: the information transmission/teacher-focused approach and the conceptual change/student-focused approach. The present study analyzes the relationship between teachers’ approaches to teaching and high school students’ approaches to learning. The data were analyzed by fitting a two-level structural equation model based on the hypothesis that student academic achievement is significantly determined by the way they study and that the way they study is partially determined by the way teachers teach. The participants were high school students (778 twelfth graders) enrolled in biology courses and their teachers (40 total). The same model was proposed at both levels (i.e., within and between levels) and fit the data quite well. As expected, within level, the effects of the ‘approaches to learning’ on ‘biology achievement’ regression were far larger than the corresponding effects at between level. The central findings suggest worthy directions for future research.