Reliability of NIRS portable device for measuring intercostal muscles oxygenation during exercise     

Felipe Contreras-Briceño  Maximiliano Espinosa-Ramirez  Gonzalo Hevia  Diego Llambias  Miguel Carrasco  Francisco Cerda 《Journal of sports sciences》2013,31(23):2653-2659

ABSTRACT

This study assessed the intra-individual reliability of oxygen saturation in intercostal muscles (SmO₂-m.intercostales) during an incremental maximal treadmill exercise by using portable NIRS devices in a test-retest study. Fifteen marathon runners (age, 24.9 ± 2.0 years; body mass index, 21.6 ± 2.3 kg·m^?2; V?O₂-peak, 63.7 ± 5.9 mL·kg^?1·min^?1) were tested on two separate days, with a 7-day interval between the two measurements. Oxygen consumption (V?O₂) was assessed using the breath-by-breath method during the V?O₂-test, while SmO₂ was determined using a portable commercial device, based in the near-infrared spectroscopy (NIRS) principle. The minute ventilation (VE), respiratory rate (RR), and tidal volume (Vt) were also monitored during the cardiopulmonary exercise test. For the SmO₂-m.intercostales, the intraclass correlation coefficient (ICC) at rest, first (VT1) and second ventilatory (VT2) thresholds, and maximal stages were 0.90, 0.84, 0.92, and 0.93, respectively; the confidence intervals ranged from ?10.8% – +9.5% to ?15.3% – +12.5%. The reliability was good at low intensity (rest and VT1) and excellent at high intensity (VT2 and max). The Spearman correlation test revealed (p ≤ 0.001) an inverse association of SmO₂-m.intercostales with V?O₂ (ρ = ?0.64), VE (ρ = ?0.73), RR (ρ = ?0.70), and Vt (ρ = ?0.63). The relationship with the ventilatory variables showed that increased breathing effort during exercise could be registered adequately using a NIRS portable device.  相似文献   

Looking at learning approaches from the angle of student profiles     

Eva Kyndt  Filip Dochy  Katrien Struyven  Eduardo Cascallar 《教育心理学》2012,32(4):493-513

This study starts with investigating the relation of perceived workload, motivation for learning and working memory capacity (WMC) with students’ approaches to learning. Secondly, this study investigates if differences exist between different student profiles concerning their approach to the learning and the influence of workloads thereon. Results show a relation for workload and motivation but not for WMC. By means of a cluster analysis, three student profiles were identified based on WMC and motivation. Students characterised by high WMC and average motivation scored higher on surface approaches and lower on deep approaches than students with high autonomous motivation. These latter students also score higher on deep approaches than students characterised by low WMC. Finally, it was found that all student profiles responded the same to the influence of workload. In contrast with prior research, deep approaches were higher when the workload was higher.  相似文献   

The effects of classroom socioeconomic composition on student’s civic knowledge in Chile     

Diego Collado  Catalina Lomos  Ides Nicaise 《School Effectiveness & School Improvement》2013,24(3):415-440

In Chile, the influence of the socioeconomic make-up of classrooms on achievement has been extensively studied in mathematics and language, but less in currently important non-traditional subjects such as civic knowledge. This paper analyses the effects of the socioeconomic composition of classrooms on students’ civic knowledge achievement in Chile, using the International Civic and Citizenship Education Study 2009 and a multilevel methodology. This research finds positive influences of higher socioeconomic intakes of 36% of one standard deviation in test scores. These results suggest that in the socioeconomically segregated Chilean education system, these effects would contribute to widening the civic knowledge attainment gap between pupils attending affluent and less affluent schools. In addition, this research finds that, on average, students with a higher individual socioeconomic status are more sensitive to these influences and that socioeconomic composition effects are more acute in the private-voucher sector than in the public sector.  相似文献   

The interplay of learning approaches and self-efficacy in secondary school students’ academic achievement in science     

Diego Ardura  Arturo Galán 《International Journal of Science Education》2013,35(13):1723-1743

ABSTRACT

The aim of the present investigation was to analyse the role of academic self-efficacy and approaches to learning in general and in Physics and Chemistry academic achievements. The sample comprised 507 secondary school students of two Spanish schools and the study was conducted in the context of a Physics and Chemistry subject. Structural equation models showed that surface motive was the only type of learning approach directly related to performance. Besides, our models revealed that self-efficacy plays an important role as a mediating variable between the surface strategy and the deep motive learning approaches and academic achievement. Gender effects were also studied as girls showed higher levels of achievement both in general performance and in Physics and Chemistry. Implications for science education and suggestions for future research of these findings are also discussed.  相似文献   

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

Flávia Maria  Teixeira dos Santos  Eduardo Fleury Mortimer 《International Journal of Science Education》2013,35(9):1095-1110

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.  相似文献   

Access to higher education in Chile: A public vs. private analysis     

Oscar Espinoza  Luis Eduardo González 《Prospects》2013,43(2):199-214

  相似文献   

El ordenador como metáfora: Las posibilidades educativas de LOGO     

Eduardo Martí 《Infancia y Aprendizaje》2013,36(26):47-64

Resumen

El autor considera al LOGO como un prototipo de la utilización educativa de los microordenadores que hace hincapié en la autonomía del aprendizaje y a sus aspectos heurísticos.

Desde postulados teóricos de la psicología genética de Piaget, analiza algunas de las particularidades psicológicas y pedagógicas de LOGO: unidades de base significativas para el niño, carácter constructivo e interactivo del aprendizaje, estatuto positivo del error, posibilidad de reflexionar sobre la propia actividad de aprendizaje.

Estos puntos son ilustrados con ejemplos de conductas de niños aprendiendo a programar con LOGO.  相似文献   

When access to drugs meets catch-up: Insights from the use of CL threats to improve access to ARV drugs in Brazil     

Shyama V. Ramani  Eduardo Urias 《Research Policy》2018,47(8):1538-1552

Access to affordable lifesaving medicines is considered a human right. This leads to a question largely understudied in the catch-up literature on accumulation of industrial capabilities. Can the need to improve access to an essential commodity impact the sectoral catch-up trajectory of the corresponding industry? In 1996, Brazil initiated a policy of universal and free access to highly-active ARV therapy, which put an enormous pressure on the Brazilian Ministry of Health (MoH). In order to ensure an adequate supply of ARVs in the public healthcare system with a limited budget, MoH started negotiating price reductions for high-cost patented drugs, often deploying the threat of using compulsory licensing. Through a scoping review of the literature and construction of the Brazilian case study, the paper explores how the need to access is impacted by prior catch-up in the pharmaceutical sector and triggers in turn future sectoral catch-up. It shows that price negotiations may or may not impact both catch-up and access positively. Catch-up can provide bargaining strength in price negotiations and have a positive inter-temporal impact on both future catch-up and access. However, results suggest that only successful catch-up can lead to long term access, as the capabilities accumulated in aborted catch-up are not sufficient for large scale production of low cost essential medicines. Thus, industrial policy and health policy can impact one another and twining between catch-up and access can be helpful.  相似文献   

Parasympathetic activity delayed after self-paced exercise     

Lucas Rosiello Trojbicz  Mayara Vieira Damasceno  Leonardo Alves Pasqua  Arthur Fernandes Gáspari  Adriano Eduardo Lima-Silva 《European Journal of Sport Science》2018,18(6):842-850

The main purpose of this study was to compare the effect of the constant load and self-paced exercise with similar total work on autonomic control after endurance exercise. Ten physically active men were submitted to (i) a maximal incremental exercise test, (ii) a 4-km cycling time trial (4-km TT), and (iii) a constant workload test with identical total external work performed at 4-km TT. Gas exchange was measured throughout the tests, while blood lactate, heart rate, and heart rate variability (HRV) were measured during the passive recovery. Power output measured at the last lap (i.e. 3600–4000?m) of 4-km TT (316?±?89?W) was statistically higher than power output measured at the end of the constant workload exercise (211?±?42?W). The 4-km TT produced higher values of blood lactate concentration (8.8?±?2.1?mmol?L^?1) than the constant workload test (7.8?±?2.1?mmol?L^?1). The heart rate recovery measured at 60?s (constant workload: 37?±?7?bpm; 4-km TT: 30?±?6) and 120?s (constant workload: 57?±?9?bpm; 4-km TT: 51?±?9?bpm) were higher in the constant workload than in the self-paced exercise. The HRV (i.e. RMSSD30s) was statistically higher in the constant load exercise measured at 120, 420, 450, 480, 540, and 570?s than the self-paced exercise. These findings suggest that the autonomic control responses were dependent of the endurance exercise modalities, with parasympathetic activity being delayed after self-paced exercise, as evidenced by post-exercise heart rate indices.  相似文献   

Fast distributed algebraic connectivity estimation in large scale networks     

Eduardo Montijano  Juan I. Montijano  Carlos Sagues 《Journal of The Franklin Institute》2017,354(13):5421-5442

This paper presents a distributed method to estimate the algebraic connectivity of fixed undirected communication graphs. The proposed algorithm uses bisection to estimate the second smallest eigenvalue of the Laplacian matrix associated to the graph. In order to decide the sub-interval in which the eigenvalue is contained, a distributed averaging algorithm based on Chebyshev polynomials is considered together with a max consensus algorithm. The information exchanged by neighbors in the graph each communication round is constant and independent of the size of the network, making it scalable to large networks. Besides, exploiting the convergence properties of Chebyshev polynomials we provide a direct estimation of the algebraic connectivity so that, instead of the midpoint of the bisection interval, the new approximation can be used. Finally, our algorithm also provides upper and lower bounds on the algebraic connectivity and an estimation of the Fiedler eigenvector associated to it. Simulations in large networks demonstrate the scalability and accuracy of the algorithm.  相似文献