The nature and development of hypothetico‐predictive argumentation with implications for science teaching

This paper explicates a pattern of scientific argumentation in which scientists respond to causal questions with the generation and test of alternative hypotheses through cycles of hypothetico‐predictive argumentation. Hypothetico‐predictive arguments are employed to test causal claims that exist on at least two levels (designated stage 4 in which the causal claims are perceptible, and stage 5 in which the causal claims are imperceptible). Origins of the ability to construct and comprehend hypothetico‐predictive arguments at the highest level can be traced to pre‐verbal reasoning of the sensory‐motor child and the gradual internalization of verbally mediated arguments involving nominal, categorical, causal and, finally, theoretical propositions. Presumably, the ability to construct and comprehend hypothetico‐predictive arguments (an aspect of procedural knowledge) is necessary for the construction of conceptual knowledge (an aspect of declarative knowledge) because such arguments are used during concept construction and conceptual change. Science instruction that focuses on the generation and debate of hypothetico‐predictive arguments should improve students' conceptual understanding and their argumentative/reasoning skills.     

La representación cognitiva de los verbos. Aproximación descriptiva y evolutiva

Resumen

Con el objeto de tener un mayor conocimiento del funcionamiento de las formas verbales en castellano, este trabajo aporta datos empíricos relativos a la manera cómo se representan las características del proceso (Aktionsart) descritas por el verbo. Tres son los factores estudiados: la duratividad, la resultatividad y la iteratividad o continuidad del proceso. Utilizando una metodología de representación gráfica se han recogido datos de una población de 42 adultos y 72 niños distribuidos en 4 grupos correspondientes a los cursos 2°, 4°, 6° y 8°

Los resultados obtenidos con los nueve verbos estudiados demuestran, por un lado, la validez del método ya que hace aparecer una neta dicotomía que opone los procesos resultativos no durativos a los no resultativos durativos, y por otro, que la duratividad y la resultatividad del proceso son captados de manera muy semejante por los adultos y por los niños de 4°, 6.° y 8.°, si bien los de 2.° denotan un menor acuerdo interindividual. Por último, el factor duratividad o iteratividad no constituye en esta prueba una dimensión discriminante.     

The impact of impairment on kinematic and kinetic variables in Va’a paddling: Towards a sport-specific evidence-based classification system for Para Va’a

ABSTRACT

Para Va’a is a new Paralympic sport in which athletes with trunk and/or leg impairment compete over 200 m. The purpose of this study was to examine the impact of impairment on kinematic and kinetic variables during Va’a ergometer paddling. Ten able-bodied and 44 Para Va’a athletes with impairments affecting: trunk and legs (TL), legs bilaterally (BL) or leg unilaterally (UL) participated. Differences in stroke frequency, mean paddling force, and joint angles and correlation of the joint angles with paddling force were examined. Able-bodied demonstrated significantly greater paddling force as well as knee and ankle flexion ranges of movement (ROM) on the top hand paddling side compared to TL, BL and UL. Able-bodied, BL and UL demonstrated greater paddling force and trunk flexion compared to TL, and UL demonstrated larger bottom hand paddling side knee and ankle flexion ROM compared to BL. Significant positive correlations were observed for both male and female athletes between paddling force and all trunk flexion angles and ROM in the trunk and pelvis rotation and bottom hand paddling side hip, knee and ankle flexion. The results of this study are important for creating an evidence-based classification system for Para Va’a.     

Reanalyzing the 16pf-5 second order structure: Exploratory versus confirmatory factorial analysis

In the present study, the second order structures of the 16PF-5 for 3, 4, 5 and 6 factors are analysed in a sample of 636 undergraduate students and their friends and relatives, with a mean age of 25.09 years (sd: 9.20). A two-stage analysis with Exploratory and Confirmatory Factor Analysis (EFA and CFA) was performed assigning subjects either to a calibration sample (314 subjects), or to a validation sample (322 subjects). First, EFAs were conducted for each of the 4-factor structures with the calibration sample, and second, CFAs were specified and assessed also for the 4-factor different structures. Four different situations were tested, simple structure, secondary loadings >.30, modification indices between covariance error terms >20, and modification indices between covariance error terms >15. Results show that the 16PF-5 simple structure yields poor fit indices throughout all models, although when incorporating secondary loadings and correlating the variances of the error terms with modification indices >15, the 5-factor model appears to be the best representation of observed data. The usefulness of CFA in the study of personality structural questionnaires is discussed in the light of these results.     

Kinetics of elite unilateral below-elbow amputee running

The role of the upper limbs in human locomotion and their influence on ground reaction force (GRF) have been extensively examined for walking and slow running. However, research has focused on unimpaired populations and has not evaluated high-speed running. In this study, the GRFs of an unilateral upper limb amputee athlete [missing right forearm, personal bests (PB): 400 m: 0:48.45 min, 800 m: 1:50.92 min] running at speeds of 5.4 and 8 m/s were collected using four floor-mounted force plates in a 100 m tartan track recording at 1000 Hz. The amputee athlete also performed trials with a running speed of 8 m/s wearing a weighted cuff on his impaired arm (0.5 and 1 kg, respectively). GRF data (without additional weight) were compared to those of an unimpaired athlete with similar PBs and anthropometry (age, height, weight). All data were evaluated for anterior–posterior, medial–lateral and vertical GRF as well as for stance phase (SP) duration and free moment (FM) values and a paired Student-t test (\(\alpha =5\) %) was performed on maximum and minimum values of the respective data sets comparing the left and right side of both athletes with each other, but no intersubjective comparisons were performed. The results revealed that vertical GRF showed significant differences for the impaired athlete at both running speeds comparing left and right foot, whereas the unimpaired athlete showed no significant differences in this matter at all. Medial–lateral GRF showed highly significant differences between the left and right foot of both athletes at both running speeds, whereas the results for anterior–posterior GRF and FM, however, showed ambiguous results. The trials with additional weight on the impaired limb led to significant differences for SP duration, but not for all conditions, and left–right differences did not change with additional weight. GRFs were found to differ in minimum medial–lateral GRF with no and heavy weight, maximum medial–lateral GRF within all weight conditions and maximum vertical GRF with no and heavy weight. For the FM, the overall pattern changed drastically and maximum FM showed a highly significant difference between the left and right foot, but none between the different conditions for both feet. Even though more significant asymmetries could be revealed for the impaired athlete, no general conclusion can be drawn at this point, given the limitations of the here presented study (low number of subjects available, anthropometric data of the impaired athlete could not be assessed).