Predicting centre of mass horizontal speed in low to severe swimming intensities with linear and non-linear models

We aimed to compare multilayer perceptron (MLP) neural networks, radial basis function neural networks (RBF) and linear models (LM) accuracy to predict the centre of mass (CM) horizontal speed at low-moderate, heavy and severe swimming intensities using physiological and biomechanical dataset. Ten trained male swimmers completed a 7 × 200 m front crawl protocol (0.05 m.s^?1 increments and 30 s intervals) to assess expiratory gases and blood lactate concentrations. Two surface and four underwater cameras recorded independent images subsequently processed focusing a three-dimensional reconstruction of two upper limb cycles at 25 and 175 m laps. Eight physiological and 13 biomechanical variables were inputted to predict CM horizontal speed. MLP, RBF and LM were implemented with the Levenberg-Marquardt algorithm (feed forward with a six-neuron hidden layer), orthogonal least squares algorithm and decomposition of matrices. MLP revealed higher prediction error than LM at low-moderate intensity (2.43 ± 1.44 and 1.67 ± 0.60%), MLP and RBF depicted lower mean absolute percentage errors than LM at heavy intensity (2.45 ± 1.61, 1.82 ± 0.92 and 3.72 ± 1.67%) and RBF neural networks registered lower errors than MLP and LM at severe intensity (2.78 ± 0.96, 3.89 ± 1.78 and 4.47 ± 2.36%). Artificial neural networks are suitable for speed model-fit at heavy and severe swimming intensities when considering physiological and biomechanical background.     

Bone quality in young adults with intellectual disability involved in adapted competitive football

The objective of this study was to analyse bone quality parameters of football players with intellectual disability (ID) participating in adapted competitive football. Sixty-seven male football players with ID were studied: 22 with Down syndrome (DS) and 45 without DS. The average age was 26 years (range: 16 ? 50 years). A group of 25 age-matched sedentary individuals with ID (11 DS and 14 non-DS) and another group of 20 healthy participants of the same age group not involved in competitive football were comparatively analysed. There were no differences in the bone quality parameters when the healthy sedentary individuals were compared with both the sedentary and the football players with ID. However, the speed of sound (SOS), T-score, and estimated bone mineral density (BMD) were of higher values in the football players with ID than in the sedentary ID group (p?p?T-scores (p?p?T-scores less than ?1.5. Two of the 14 sedentary non-DS participants (14.3%) had T-scores indicating osteoporosis. In summary, the ID population actively involved in football showed higher values of bone mass parameters than their sedentary ID and healthy peers. The participants with non-DS ID showed a higher prevalence of osteoporosis than the football players with DS. Participation in sports seems to prevent bone loss in individuals with ID.     

A general result on non-existence of finite-time stable equilibria in fractional-order systems

It is well known that a fractional-order system with a continuous right hand side does not have finite-time stable equilibria, but the discontinuous case has remained elusive in literature. Thus, based on novel mathematical tools, recently published in literature, it is demonstrated that attaining finite-time stable equilibria is not possible for a fractional-order system, not even in the case of an impulsive or discontinuous feedback. In consequence, it is demonstrated that, for a fractional-order system, a Lyapunov stable equilibrium cannot be at the same time finite-time stable.     

The visible hand of cluster policy makers: An analysis of Aerospace Valley (2006-2015) using a place-based network methodology

The paper focuses on cluster policies with particular attention to the role of R&D collaborative incentives in the structuring of knowledge networks in clusters. We disentangle the main network failures in regional innovation systems, and discuss the selection procedures designed by policy makers to foster knowledge collaborations. We draw evidence from the French Aerospace Valley cluster from 2006 to 2015. The case study is based on a dataset of 248 granted research consortia, from which we build 4-cohort knowledge networks that enable us evidencing the evolving structural properties of the cluster over time. We suggest avoiding the bias and limitations of 1 and 2-mode network analysis by developing an original place-based network methodology that emphasizes on structural equivalence and groups’ behaviors. We discuss the results focusing on the convergence degree between the structural properties of the cluster selected by the Program and the policy makers’ objectives. Finally, the methodology allows us to identify the agents of the structural and technological changes observed throughout the period.     

Teaching-learning methods and their effect on professional development and the development of graduates’ competencies / Métodos de enseñanza-aprendizaje y su efecto en el desarrollo profesional y competencial de los egresados

This article analyses the effect of the teaching-learning methods used in Spanish universities on three measures of educational output: average mark, graduates’ assessment of their professional performance in different dimensions, and their assessment of the acquisition of professional competencies and skills. Multi-level models were used in which graduates (first level) are grouped by field of study (second level). The Class attendance and Written work methods have the most influence on the average mark but influence the graduates’ working future the least, as measured with assessments of professional aspects or competencies. In contrast, Problem-based learning, In-company internships and Practical and methodological knowledge are the methods that bear the most influence on the graduates’ professional careers and their development of specific professional competencies.     

The influence of body discourses on adolescents’ (non)participation in physical activity

Drawing on semi-structured interviews with older adolescents, this article examines how healthism, ideal body discourses and performative body discourses influence their (non)participation in physical activity (PA) and their identity construction concerning exercise, sport and physical education. We illustrate that body transformation through PA, and related slim body desire and the fear of masculinised female bodies, affect adolescents’ decisions to engage in or drop out of sport. Also, a non-hegemonic body shape combined with a display of low physical competence triggers classmate and teachers’ rejection and marginalisation, affecting adolescents’ construction of embodied identities and preventing them from being active. Finally, adolescents who are competent in sport are less influenced by ideal body discourses than by performative body discourses. We highlight the health promotion effects of these hegemonic discourses and suggest strategies to challenge them.     

Bone mass,bone mineral density and muscle mass in professional golfers

The aim of this study was to determine the effects of long-term professional golf participation on whole-body and regional bone mass and density. Dual-energy X-ray absorptiometry was performed on 15 male professional golfers and 18 sedentary individuals, matched for sex, race, age (29+/-1 and 25+/-1 years, respectively), body mass (79+/-2 and 74+/-2 kg), height (1.78+/-0.01 and 1.77+/-0.02 m) and percent body fat (20+/-2 and 21+/-2%; mean +/- sx). We found that long-term professional golf participation is not associated with significant increments in regional or whole-body bone mass or density. Neither the lumbar spine nor the femoral neck showed any noticeable enhancement of bone mass in professional golfers compared with controls from the same population. The only effect of professional golf participation on regional body composition was a 9% increase in muscle mass in the dominant arm (P < 0.05).     

Sodium bicarbonate ingestion does not alter the slow component of oxygen uptake kinetics in professional cyclists

We examined the effects of pre-exercise sodium bicarbonate (NaHCO3) ingestion on the slow component of oxygen uptake (VO2) kinetics in seven professional road cyclists during intense exercise. One hour after ingesting either a placebo or NaHCO3 (0.3 g x kg body mass(-1)), each cyclist (age, 25 +/- 2 years; VO2max, 74.7 +/- 5.9 ml x kg(-1) x min(-1); mean +/- s) performed two bouts of 6 min duration at an intensity of 90% VO2max interspersed by 8 min of active recovery. Gas exchange and blood data (pH, blood lactate concentration and [HCO3-]) were collected during the tests. In both bouts, the slow component of VO2 was defined as the difference between end-exercise VO2 and the VO2 at the end of the third minute. No significant difference was found in the slow component of VO2 between conditions in the first (NaHCO3, 210 +/- 69 ml; placebo, 239 +/- 105 ml) or second trial (NaHCO3, 123 +/- 88 ml; placebo, 197 +/- 101 ml). In conclusion, pre-exercise NaHCO3 ingestion did not significantly attenuate the VO2 slow component of professional road cyclists during high-intensity exercise.     

La Genèse de l’Opération d’Addition. Analyse de quelques Variables Significatives dans la Résolution de Problèmes Additifs

European Journal of Psychology of Education -     

A motivation perspective on faculty mentoring: the notion of “non-intrusive” mentoring practices in science and engineering

Scholars have offered numerous approaches and best practices for mentoring faculty, many of which have provided valuable insight into the complex nature of the mentoring process. Yet, little attention has been paid to how faculty mentoring practices can influence a mentee’s intrinsic motivation. Through a series of 15 interviews with faculty members from mathematics, engineering, and life science, coupled with the use of self-determination theory, the author demonstrates how disciplinary backgrounds influence their needs for autonomy, competency, and connectedness, which effects their intrinsic motivation to engage in scholarly work. The author highlights three themes that speak to the notion of “non-intrusive” mentoring practices that can help foster and sustain motivation, and argues that future research is needed to shed more light on how disciplinary cultures influence mentoring.