On the Concept of Energy: Eclecticism and Rationality

In the theory of heat of the first half of the nineteenth century, heat was a substance. Mayer and Joule contradicted this thesis but developed different concepts of heat. Heat was a force for Mayer and a motion for Joule. Both Mayer and Joule determined the mechanical equivalent of heat. This result was, however, justified in accordance with those concepts of heat. Mayer’s characterisation of force reappears in the very common textbook definition ‘energy cannot be created or destroyed but only transformed’ and his theory led to a phenomenological approach to energy. Joule and Thomson’s concept of heat led to a mechanistic approach to energy and to the common definition ‘energy is the capacity of doing work’. One and the same term ‘energy’ subsumed these two approaches. The problematic concept of energy, energy as a substance, appears then as a result of an eclectic development of the concept. Another approach, which appeared in the 1860s, is directly based on the mechanical equivalent of heat and can be characterized by the use of ‘principle of equivalence’ instead of ‘principle of energy conservation’. Unlike the others, this approach, which has been lost, poses no problems with the concept of energy. The problems with the energy concept as to the kind of phenomena dealt with in the present paper can, however, be overcome, as we shall see, in distinguishing between that which comes from experiments and that which is an interpretation of the experimental results within a conceptual framework.     

Enfants autochtones et apprentissage: la corporalité comme langage en Amérique du Sud tropicale

In this article on the cultural context of children's learning processes among the indigenous peoples of tropical South America, the author aims to show how in these cultures the human body offers a language and a mechanism central to the process of production, elaboraton and transmission of knowledge, skills and emotions. She works from the assumption that the construction of a child's identity is a process which takes place in the body, creating a synthesis of social, cosmological, psychological, emotional and cognitive meanings. In constructing an ethnography of the Akwe~-Xavante and Akwe~-Xerente peoples of central Brazil, the author refers to recent anthropological debates on the cosmology and outlook of the indigenous peoples of this region, as well as to the literature of the new discipline known as "anthropology of the child".     

Building communities in higher education: the case of nursing

The historic and current case to retain a focused clinical nursing identity within an academic context is explicit; however there is tension between the need for excellence in teaching and research, and obligation to maintain a credible clinical identity. Nursing is politically and vocationally advanced but, arguably, weaker academically. Considered an ‘old vocation’ but a ‘young discipline’, nursing lacks the traditional background found in established academic communities. Nurses still find it difficult to ‘let go’ of the past and new academics will often try to re-create a clinical role because they lack confidence in their ability to fulfil an academic one. Moving forward, the new graduate nursing programmes and the growing number of hybrid or ‘pracademic’ roles spanning education and practice will, through the co-creation of knowledge, challenge discipline boundaries and produce a new generation of leaders for the profession.     

Radical investment in the curriculum in times of Covid-19: Can we question the anti-science discourses?

PROSPECTS - This article questions the centrality of knowledge and learning in the curriculum, as well as the restriction of education to learning even when education is thought of as consisting of...     

Effect of biological maturation on maximal oxygen uptake and ventilatory thresholds in soccer players: an allometric approach

In this study, we investigated the effect of biological maturation on maximal oxygen uptake ([Vdot]O(2max)) and ventilatory thresholds (VT(1) and VT(2)) in 110 young soccer players separated into pubescent and post-pubescent groups.. Maximal oxygen uptake and [Vdot]O(2) corresponding to VT(1) and VT(2) were expressed as absolute values, ratio standards, theoretical exponents, and experimentally observed exponents. Absolute [Vdot]O(2) (ml · min(-1)) was different between groups for VT(1), VT(2), and [Vdot]O(2max). Ratio standards (ml · kg(-1) · min(-1)) were not significantly different between groups for VT(1), VT(2), and [Vdot]O(2max). Theoretical exponents (ml · kg(-0.67) · min(-1) and ml · kg(-0.75) · min(-1)) were not properly adjusted for the body mass effects on VT(1), VT(2), and [Vdot]O(2max). When the data were correctly adjusted using experimentally observed exponents, VT(1) (ml · kg(-0.94) · min(-1)) and VT(2) (ml · kg(-0.95) · min(-1)) were not different between groups. The experimentally observed exponent for [Vdot]O(2max) (ml · kg(-0.90) · min(-1)) was different between groups (P = 0.048); however, this difference could not be attributed to biological maturation. In conclusion, biological maturation had no effect on VT(1), VT(2) or [Vdot]O(2max) when the effect of body mass was adjusted by experimentally observed exponents. Thus, when evaluating the physiological performance of young soccer players, allometric scaling needs to be taken into account instead of using theoretical approaches.     

Reliability and validity of Yo-Yo tests in 9- to 16-year-old football players and matched non-sports active schoolboys

The purpose of this study was to examine the test–retest reliability and construct validity of three age-adapted Yo-Yo intermittent tests in football players aged 9–16 years (n?=?70) and in age-matched non-sports active boys (n?=?72). Within 7 days, each participant performed two repetitions of an age-related intensity-adapted Yo-Yo intermittent test, i.e. the Yo-Yo intermittent recovery level 1 children's test for 9- to 11-year-olds; the Yo-Yo intermittent endurance level 1 for 12- to 13-year-olds and the Yo-Yo intermittent endurance level 2 test for 14- to 16-year-olds. Peak heart rate (HR_peak) was determined for all tests. The distance covered in the tests was 57% (1098?±?680 vs. 700?±?272?m), 119% (2325?±?778 vs. 1062?±?285?m) and 238% (1743?±?460 vs. 515?±?113?m) higher (p?≤?.016), respectively for football-trained than for non-sports active boys aged 9–11, 12–13 and 14–16 years. The typical errors of measurement for Yo-Yo distance, expressed as a percentage of the coefficient of variation (confidence interval), were 11.1% (9.0–14.7%), 10.1% (8.1–13.7%) and 8.5% (6.7–11.7%) for football players aged 9–11, 12–13 and 14–16 years, respectively, with corresponding values of 9.3% (7.4–12.8%), 10.2% (8.1–14.0%) and 8.5% (6.8–11.3%) for non-sports active boys. Intraclass correlation coefficient values for test–retest were excellent in both groups (range: 0.844–0.981). Relative HR_peak did not differ significantly between the groups in test and retest. In conclusion, Yo-Yo intermittent test performances and HR_peak are reliable for 9- to 16-year-old footballers and non-sports active boys. Additionally, performances of the three Yo-Yo tests were seemingly better for football-trained than for non-sports active boys, providing evidence of construct validity.     

Transversal traits in science education research relevant for teaching and research: A meta‐interpretative study

This study is a meta‐interpretative analysis that focuses on research conducted and published by other researchers. Concepts central to this study include global practical relevance, curriculum design, and formative situation. We analyzed 35 studies selected from 374 published studies in the years 2000 and 2001 in three journals referenced in the International Scientific Index. Using a replicable methodology developed specifically for this research, we found evidence of s clusters of variables that suggest the existence of transversal traits in the 35 science education research studies. These results form a reference framework of theoretical and practical knowledge relevant for research and practice pertaining to teaching and learning science. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 45: 574–599, 2008     

Enfants autochtones et apprentissage: la corporalité comme langage en Amérique du Sud tropicale

In this article on the cultural context of children's learning processes among the indigenous peoples of tropical South America, the author aims to show how in these cultures the human body offers a language and a mechanism central to the process of production, elaboraton and transmission of knowledge, skills and emotions. She works from the assumption that the construction of a child's identity is a process which takes place in the body, creating a synthesis of social, cosmological, psychological, emotional and cognitive meanings. In constructing an ethnography of the Akwe~-Xavante and Akwe~-Xerente peoples of central Brazil, the author refers to recent anthropological debates on the cosmology and outlook of the indigenous peoples of this region, as well as to the literature of the new discipline known as "anthropology of the child".     

Movement behaviors and their association with depressive symptoms in Brazilian adolescents: A cross-sectional study

Background:Physical activity,sleep,and sedentary behaviors compose 24-h movement behaviors and have been independently associated with depressive symptoms.However,it is not clear whether it is the movement behavior itself or other contextual factors that are related to depressive symptoms.The objective of the present study was to examine the associations between self-reported and accelerometer-measured movement behaviors and depressive symptoms in adolescents.Methods:Cross-sectional data from 610 adolescents(14-18 years old)were used.Adolescents answered questions from the Center for Epidemiological Studies Depression scale and reported time spent watching videos,playing videogames,using social media,time spent in various physical activities,and daytime sleepiness.Wrist-worn accelerometers were used to measure sleep duration,sleep efficiency,sedentary time,and physical activity.Mixed-effects logistic regressions were used.Results:Almost half of the adolescents(48%)were classified as being at high risk for depression(score≥20).No significant associations were found between depressive symptoms and accelerometer-measured movement behaviors,self-reported non-sport physical activity,watching videos,and playing videogames.However,higher levels of self-reported total physical activity(odd ratio(OR)=0.92,95%confidence interval(95%CI):0.86-0.98)and volume of sports(OR=0.88,95%CI:0.79-0.97),in minutes,were associated with a lower risk of depression,while using social media for either 2.0-3.9 h/day(OR=1.77,95%CI:1.58-2.70)or>3.9 h/day(OR=1.67,95%CI:1.10-2.54),as well as higher levels of daytime sleepiness(OR=1.17,95%CI:1.12-1.22),were associated with a higher risk of depression.Conclusion:What adolescents do when they are active or sedentary may be more important than the time spent in the movement behaviors because it relates to depressive symptoms.Targeting daytime sleepiness,promoting sports,and limiting social media use may benefit adolescents.