Blood lactate response and critical speed in swimmers aged 10–12 years of different standards

It has previously been shown that measurement of the critical speed is a non-invasive method of estimating the blood lactate response during exercise. However, its validity in children has yet to be demonstrated. The aims of this study were: (1) to verify if the critical speed determined in accordance with the protocol of Wakayoshi et al. is a non-invasive means of estimating the swimming speed equivalent to a blood lactate concentration of 4 mmol·l^-1 in children aged 10-12 years; and (2) to establish whether standard of performance has an effect on its determination. Sixteen swimmers were divided into two groups: beginners and trained. They initially completed a protocol for determination of speed equivalent to a blood lactate concentration of 4 mmol·l^-1. Later, during training sessions, maximum efforts were swum over distances of 50, 100 and 200 m for the calculation of the critical speed. The speeds equivalent to a blood lactate concentration of 4 mmol·l^-1 (beginners = 0.82±0.09 m·s^-1 , trained = 1.19±0.11 m·s^-1; mean±s) were significantly faster than the critical speeds (beginners = 0.78±0.25·s^-1 , trained = 1.08±0.04 m·s^-1) in both groups. There was a high correlation between speed at a blood lactate concentration of 4 mmol·l^-1 and the critical speed for the beginners (r = 0.96, P ? 0.001), but not for the trained group (r = 0.60, P > 0.05). The blood lactate concentration corresponding to the critical speed was 2.7±1.1 and 3.1±0.4 mmol·l^-1 for the beginners and trained group respectively. The percent difference between speed at a blood lactate concentration of 4 mmol·l^-1 and the critical speed was not significantly different between the two groups. At all distances studied, swimming performance was significantly faster in the trained group. Our results suggest that the critical speed underestimates swimming intensity corresponding to a blood lactate concentration of 4 mmol·l^-1 in children aged 10-12 years and that standard of performance does not affect the determination of the critical speed.     

Competition and diversity in higher education: an empirical approach to specialization patterns of Portuguese institutions

The expansion of higher education systems has often been associated with the need for increasing diversification, namely at the program level, based on the pressures to adapt more general programmes to a more diverse student population and multiple regional, social, and economic needs. This paper explores empirically the question of programme diversity by drawing on the Portuguese higher education’ experience, which presented massive expansion during the last decades and significant institutional competition in recent years. The study provides a longitudinal approach and analyzes in detail the evolution of diversification and specialization of the public and private sectors, as well as the university and polytechnic subsectors. The analysis aims at helping to illustrate the relevance of analysing diversity from an empirical point of view and its contribution to our understanding of the complex relationships between competition and diversity in contemporary higher education.     

How emotions shape the relationship between a chemistry teacher and her high school students

In this article we analyse the interaction between a high school chemistry teacher and her students from two different classes, emphasizing how emotions, affects and feelings contributed to, or obstructed, the dynamic of interactions. The data come from an ethnographic research approach and include videotapes of the lessons, interviews and field notes. Using the distinction introduced by Damasio between primary and secondary emotions, and between emotions and feelings, we describe how the background feelings emerged in different ways in the two classrooms. In class B, the relationships were constructed in a friendly way from the very beginning. The positive emotions that contributed to raising positive background feelings occurred in a high number and frequency. In class A, the picture was completely different, with a higher number and frequency of negative emotions. Thus, emotions and background feelings that were constructed differently in each classroom were at the heart of the different outcomes in terms of attitudes towards chemistry that arose in the two classrooms. In the paper, we also discuss the implication of this kind of analysis for science teaching generally.     

Teaching for quality learning in chemistry

In Portugal, the number of students in higher education increased from 80,000 in 1975 to 381,000 in 2000 (a change from 11% to 53% in the age group 18–22), meaning a major change in the diversity of student population with consequences well known and studied in other countries. The teaching of chemistry at the University of Aveiro, for the first‐year students of science and engineering, has been subjected to continuous attention to implement quality and student‐centred approaches. The work devoted to excellence and deep learning by several authors has been carefully followed and considered. This communication reports research work on chemistry teaching, associated with those developments for first‐year students. The work included the design of strategies and the adoption of teaching and learning activities exploring ways to stimulate active learning by improving the quality of classroom interactions. In addition to regular lectures, large classes' teaching based on student‐generated questions was explored. In order to improve students' motivation and stimulate their curiosity, conference‐lectures were adopted to deal with selected topics of wide scientific, technological and social interest. Quantitative analysis and discussion of selected case studies, together with the organization of laboratory classes based on selected enquiry‐based experiments, planned and executed by students, stimulated deep learning processes. A sample of 32 students was followed in the academic year of 2000/01 and the results obtained are here discussed in comparison with those of a sample of 100 students followed in 2001/02. Particular attention was paid to the quality of classroom interactions, the use of questions by students and their views about the course design.     

University students' depression: a cross-cultural investigation

Australian, Iranian and Portuguese university students (n?=?967) completed the University Students Depression Inventory (USDI) in English, Persian and Portuguese languages, respectively. A series of MANOVA analyses were used to examine differences in depression symptoms as an effect of the country and demographic variables. Interactions were also examined. The results indicated that country, gender and year level had some impact on the depressive symptoms of the university students. Australian students were more depressed than the Iranian and Portuguese students, while Iranian students were more depressed than the Portuguese students. Sub-scales of USDI – Lethargy, Motivation and Cognitive/Emotional – were also used to compare the depressive symptoms of students. The Australian female students reported a significantly higher level of lethargy than their male counterparts. Similarly, the first-year male students from Iran were significantly more lethargic than the first-year Iranian female students. Iranian and Portuguese male students, compared to the female students of these countries, experienced a lower level of motivation. The Australian and Iranian students, compared to the Portuguese students, reported a significantly higher level of cognitive and affective symptoms. The scores on the Cognitive/Emotional sub-scale increased with the year level. Differences among students' depression are described and implications discussed.     

Global blue carbon accumulation in tidal wetlands increases with climate change

Coastal tidal wetlands produce and accumulate significant amounts of organic carbon (C) that help to mitigate climate change. However, previous data limitations have prevented a robust evaluation of the global rates and mechanisms driving C accumulation. Here, we go beyond recent soil C stock estimates to reveal global tidal wetland C accumulation and predict changes under relative sea level rise, temperature and precipitation. We use data from literature study sites and our new observations spanning wide latitudinal gradients and 20 countries. Globally, tidal wetlands accumulate 53.65 (95%CI: 48.52–59.01) Tg C yr⁻¹, which is ∼30% of the organic C buried on the ocean floor. Modeling based on current climatic drivers and under projected emissions scenarios revealed a net increase in the global C accumulation by 2100. This rapid increase is driven by sea level rise in tidal marshes, and higher temperature and precipitation in mangroves. Countries with large areas of coastal wetlands, like Indonesia and Mexico, are more susceptible to tidal wetland C losses under climate change, while regions such as Australia, Brazil, the USA and China will experience a significant C accumulation increase under all projected scenarios.     

A cross-sectional and prospective analyse of reallocating sedentary time to physical activity on children’s cardiorespiratory fitness

Cardiorespiratory fitness (CRF) is associated with health benefits in children, improving cardiac morphology, cardiovascular disease risk factors, and biological outcomes. This study aimed to examine the substitution effects of displaying a fixed duration of sedentary time with a fixed duration of physical activity (PA) at different intensities on children’s CRF. A total of 315 children (136 boys) were assessed (age: 10.6 ± 0.6 years old). Outcomes at baseline and follow-up (16-months) were CRF determined using a maximal cycle test and sedentary time and PA measured with accelerometers. Data were analysed by isotemporal substitution analyses estimating the effect of reallocating 30 min/day of sedentary time by light (LPA), moderate (MPA) and vigorous physical activity (VPA) on CRF. VPA was positively and significantly associated with CRF cross-sectional (β = 0.026, p < 0.001) and prospectively (β = 0.010, p < 0.001). Reallocating 30 min/day of sedentary time into VPA was positively cross-sectionally (β = 0.780, p < 0.001) and prospectively (β = 0.303, p < 0.05) associated with CRF. Conversely, relocating 30-minutes of sedentary time into 30 minutes of LPA and MPA was not associated with CRF. These results suggest that reallocating an equal amount of time from sedentary into VPA is cross-sectional and prospectively associated with a favourable CRF.     

A model for the effective engagement of all stakeholders in engineering education and its pilot implementation

Methodologies for engineering learning and teaching (MELT) approach aims to enhance the attractiveness of education through science, technology, engineering and mathematics (STEM) among young people, while promoting awareness of future careers in these areas. To this end, students’ expectations are considered within university programmes, aiming to an increased engagement in STEM careers. To accomplish these goals, a new and integrated approach (MELT) is presented, involving the main stakeholders in both scientific education and society. An education framework is presented, providing guidelines for an improved collaborative approach to STEM education in the future. Results from the pilot implementation of MELT are presented, from a small-scale education parliament prototype. From these initial stage and results, it is seen that there is a need for a proper alignment of expectations from all involved stakeholders, concerning the engineering education towards society’s demands.