Fostering Distributed Science Learning Through Collaborative Technologies

TACTICS (French and Spanish acronym standing for Collaborative Work and Learning in Science with Information and Communications Technologies) is an ongoing project aimed at investigating a distributed community of learning and practice in which information and communications technologies (ICT) take the role of collaborative tools to support social construction of knowledge. This community is composed of researchers, graduate students, and high-school teachers and their students, from six schools and four universities in Canada and Mexico. It set out in fall 2000 to develop a community around the general topic of integrating concepts in science school subjects. Once a prototype community is established, it can become a terrain where different aspects could be studied. Subsequently, researchers could gradually take a back seat allowing as well as ensuring the autonomy of the school members involved and, thereby, the viability of the learning community. The set up of the proposed prototype distributed science learning community was therefore an essential yet far from trivial first step. This paper discusses the process of setting up the community and the lessons learned.     

Teaching databases in compliance with the European dimension of higher education: Best practices for better competences

The Convergence process in which European Union (EU) universities are at present involved supposes that these institutions not only have to re-structure their degree programmes, but also their teaching and learning methodologies. We study the impact of this EU process on Database teaching, comparing the practices of three different European universities and using the Convergence goals as criteria. In our discussion, we identify which aspects in each university are closer to the Convergence goals, and which are likely to help in achieving these goals.     

The association between homework and primary school children's academic achievement. International evidence from PIRLS and TIMSS

The association between time devoted to homework and children's academic achievement has long been an issue of great debate. A small number of mainly correlational studies have been conducted into this issue in a primary school setting, but have produced somewhat mixed results. In this paper we contribute to this literature by investigating the relationship between time spent upon homework and children's outcomes across 24 countries. By using a student fixed-effects approach, capturing differences in homework time amongst the same student across different school subjects, we argue that our results are likely to be subject to less confounding than much of the existing literature. We find little evidence that the amount of homework time primary school children are assigned is related to their academic achievement. This holds true across a large number of countries, survives various robustness tests and does not vary by gender or socio-economic status. We interpret this finding as suggesting that the homework assigned to primary school pupils may not be adequate to produce a positive association, and needs be improved if this time-consuming activity is ever going to bring benefits for children's academic achievement.     

Interaction between cells in dielectrophoresis and electrorotation experiments

Progress in microelectrode-based technologies has facilitated the development of sophisticated methods for manipulating and separating cells, bacteria, and other bioparticles. For many of these various applications, the theoretical modeling of the electrical response of compartmentalized particles to an external field is important. In this paper we address the analysis of the interaction between cells immersed in rf fields. We use an integral formulation of the problem derived from a consideration of the charge densities induced at the interfaces of the particle compartments. The numerical solution by a boundary element technique allows characterization of their dielectric properties. Experimental validation of this theoretical model is obtained by investigating two effects: (1) The influence that dipolar “pearl chaining” has on the dielectrophoretic behavior of human T lymphocytes and (2) the frequency variation of the spin and orbital torques of approaching insulinoma β-cells in a rotating field.     

Dignifying the educational process through conscientização

Teaching is a very complex endeavor. Embedded within this complex environment are issues of power, culture, ethnicity, and race. When teachers and students come together, in the classroom, some of these issues become visible and others remain invisible. Attempting to make influences on teaching and learning visible is one of the steps toward developing a practice framed by conscientização. Ms. Cook, the teacher of this story, is empowering herself and her students; through critical reflection that serves to deneutralize educational acts by recognizing they are embedded in issues of culture, ethnicity, politics, power, and, race. Classroom based research must be more inclusive and indeed cognizant of the mediating macrostructures that teachers deal with everyday. For example, Goldberg and Muir Welsh describe some of the students as being Latinos. In doing so, they adopts a third person as opposed to a first person view of these students. A first person view can acknowledge a dialectical relationship between race and ethnicity.     

Are practical activities and ICTs important？ Thoughts and practice of a physics teacher

The influence of teachers＇ beliefs in curriculum implementation has been explored in a number of contexts. With the aim of describing curricular beliefs about practical activities in laboratory and 1CT （information and communication technology） resources, and the relationship between thinking and practice, the author has carried out the case study of a physics teacher, both in his classroom activities and those in laboratory. The sources of information include field notes, questionnaire, interviews, planning and class observation. The results indicate that, what teachers believe is not the same as what they do, appearing more constructive in thinking and more traditional in practice. For example, they believe that ICT must be used to teach science, however, in practice, the most utilized resource is the textbook. The author considers that, taking into account this kind of incoherence is essential in order to reflect about teachers＇ knowledge of sciences, practices and the relationship between these.     

Effect of different velocity loss thresholds during a power-oriented resistance training program on the mechanical capacities of lower-body muscles

This study compared the effects of two velocity loss thresholds during a power-oriented resistance training program on the mechanical capacities of lower-body muscles. Twenty men were counterbalanced in two groups (VL10 and VL20) based on their maximum power capacity. Both groups used the same exercises, relative intensity and repetition volume, only differing in the velocity loss threshold of each set (VL10: 10% vs. VL20: 20%). Pre- and post-training assessments included an incremental loading test and a 15-m linear sprint to assess the force- and load-velocity relationships and athletic performance variables, respectively. No significant between-group differences (P > 0.05) were observed for the force-velocity relationship parameters (ES range = 0.15–0.42), the MPV attained against different external loads (ES range = 0.02–0.18) or the 15-m sprint time (ES = 0.09). A high between-participants variability was reported for the number of repetitions completed in each training set (CV = 30.3% for VL10 and 29.4% for VL20). These results suggest that both velocity loss thresholds induce similar changes on the lower-body function. The high and variable number of repetitions completed may compromise the velocity-based approach for prescribing and monitoring the repetition volume during a power-oriented resistance training program conducted with the countermovement jump exercise.     

Effect of 6-weeks WBVT on the behaviour of the lower limb muscle fibres during vertical jumping

The purpose of the current study was to examine the effect of 6 weeks of whole body vibration training (WBVT) on body composition, muscle activity of the gastrocnemius and vastus lateralis, gastrocnemius muscle architecture (static and dynamic) and ground reaction forces (performance jump) during the take-off phase of a countermovement jump in young healthy adult males. A total of 33 men (23.31 ± 5.62 years) were randomly assigned to a whole body vibration group (experimental group, EG_WBVT: n = 17; 22.11 ± 4.97 years) or a control group (CG: n = 16; 24.5 ± 6.27 years). The total duration of the intervention phase (WBVT) was 6 weeks with a frequency of 3 sessions per week. Statistically significant differences were observed (P ≤ 0.05) between pre- and post-test in the power peak (Δ 1.91 W · kg^?1; P = 0.001), take-off velocity (0.1 cm · s^?1; P = 0.002) and jump height (Δ 0.4 cm; P = 0.002) for EG_WBVT. There were no statistically significant differences in any of the body composition and muscle architecture variables. Moreover, no significant differences were found between EG_WBVT and CG nor changes in muscle activity during take-off phase of the gastrocnemius and vastus lateralis pre- versus post-training. This study suggests that a 6-week WBVT programme with increasing intensity improves jump performance but does not alter muscle activity nor muscle architecture in healthy young men.