Wavelet-based deconvolution of ultrasonic signals in nondestructive evaluation

INTRODUCTION Deconvolution of ultrasonic signals is defined as the solution of the inverse problem of convolving an input signal, known as the system function h(n), with a medium reflectivity function x(n) and can be rep- resented by y(n)=h(n)*x(n) η(n), (1) where y(n) is the measured signal, * denotes the convolution operation and η(n) is the additive noise. Recovering x(n) from the observation y(n) leads to improving the appearance and the axial resolution of the RF-signals by removin…     

Analyzing learners’ engagement and behavior in MOOCs on programming with the Codeboard IDE

Educational technology research and development - Massive Open Online Courses (MOOCs) can be enhanced with the so-called learning-by-doing, designing the courses in a way that the learners are...     

Students’ Alternative Frameworks and Teaching Strategies: a pilot study

Research has shown that students’ alternative conceptions in science are quite resistent to change, which indicates that the teaching strategies used are not appropriate and that new strategies should be implemented in order to promote conceptual change. This pilot study was carried out with 100 Portuguese 5th grade students and aims: (a) to investigate a teaching strategy geared to the students’ conceptual change, taking into account their misconceptions about scientific ideas; (b) to promote a better attitude towards science. The results of this study indicate that the teaching approach based on the pupils’ alternative ideas and that makes them reflect on their own work and ideas, seemed to increase learning of scientific concepts related to the topic ‘properties and corpuscular model of the air’ and consequently favoured conceptual change better than a ‘traditional’ approach.     

Talk about texts at the computer: using ICT to develop children's oral and literate abilities

This article describes the outcomes of recent research on children's talk while engaged in joint literacy activities in primary school (Year 5). The research is based on a conception of talk as a tool for ‘thinking together’, with computer software being treated as a resource for organising and focusing children's involvement in collaborative activities. The results are used to discuss the value of classroom talk and computer‐based activities for promoting children's literacy development.     

Explicit reasoning, creativity and co-construction in primary school children's collaborative activities

This paper describes research that explored the question of whether or not it is possible to characterise and teach a single type of educationally productive talk. We analysed and compared the quality of children's interactional strategies when jointly working on a reasoning task and a psycholinguistic task. The latter involved writing an integrated summary of three related texts. Sixth grade primary school children (11–12 years old) solved these two tasks as pre- and post-tests before and after training in the use of ‘Exploratory Talk’ (ET) to think together and argue as well as in strategies for producing summaries. After training, children improved substantially in the use of ET when solving the reasoning but not the psycholinguistic task. However, using ethnography of communication methods to analyse the talk further around the latter task revealed that both the number and quality of communicative events and acts increased importantly. These changes were accompanied by a significant improvement in the quality of the summaries produced. These findings suggest that the requirement for explicit reasoning in the definition and analysis of ET may be task dependent. To account for the common features of the educationally productive talk in the two settings, we propose the more inclusive concept of co-constructive talk to characterise the inter-subjective orientation, social ground rules and communicative actions that support effective collaboration, co-ordination and creativity.     

Nonverbal communication in crosscultural counseling: A literature review

The body of this article is a review (though not necessarily exhaustive) of current literature on nonverbal behavior as it is found in different cultures. The review is specifically aimed at counselors involved in crosscultural counseling. Material is presented on Kinesics, Proxemics and Paralanguage: three categories of nonverbal behavior that are expected to occur in counseling. Concluding remarks include a discussion of research methods employed, and of two opposing viewpoints underlying the presented research.This paper is based on the first author's M.A. Thesis completed under the direction of the second author.Loyola University of Chicago     

Caffeine improves muscular performance in elite Brazilian Jiu-jitsu athletes

Scientific information about the effects of caffeine intake on combat sport performance is scarce and controversial. The aim of this study was to investigate the effectiveness of caffeine to improve Brazilian Jiu-jitsu (BJJ)-specific muscular performance. Fourteen male and elite BJJ athletes (29.2?±?3.3?years; 71.3?±?9.1?kg) participated in a randomized double-blind, placebo-controlled and crossover experiment. In two different sessions, BJJ athletes ingested 3?mg?kg^?1 of caffeine or a placebo. After 60?min, they performed a handgrip maximal force test, a countermovement jump, a maximal static lift test and bench-press tests consisting of one-repetition maximum, power-load, and repetitions to failure. In comparison to the placebo, the ingestion of the caffeine increased: hand grip force in both hands (50.9?±?2.9 vs. 53.3?±?3.1?kg; respectively p?p?=?.02), and time recorded in the maximal static lift test (54.4?±?13.4 vs. 59.2?±?11.9?s; p?p?=?.02), maximal power obtained during the power-load test (750.5?±?154.7 vs. 826.9?±?163.7?W; p?p?=?.04). In conclusion, the pre-exercise ingestion of 3?mg?kg^?1 of caffeine increased dynamic and isometric muscular force, power, and endurance strength in elite BJJ athletes. Thus, caffeine might be an effective ergogenic aid to improve physical performance in BJJ.