Why and how mathematicians read proofs: an exploratory study     

Keith Weber  Juan Pablo Mejia-Ramos 《Educational Studies in Mathematics》2011,76(3):329-344

In this paper, we report a study in which nine research mathematicians were interviewed with regard to the goals guiding their reading of published proofs and the type of reasoning they use to reach these goals. Using the data from this study as well as data from a separate study (Weber, Journal for Research in Mathematics Education 39:431–459, 2008) and the philosophical literature on mathematical proof, we identify three general strategies that mathematicians employ when reading proofs: appealing to the authority of other mathematicians who read the proof, line-by-line reading, and modular reading. We argue that non-deductive reasoning plays an important role in each of these three strategies.  相似文献   

Donation of bodies for anatomy teaching in Chile          下载免费PDF全文

Juan Pablo Gatica‐Araneda M.D.  Patrico Alfaro‐Toloza 《Anatomical sciences education》2014,7(3):248-248

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Incidence and risk for traumatic and overuse injuries in top-level road cyclists     

De Bernardo N  Barrios C  Vera P  Laíz C  Hadala M 《Journal of sports sciences》2012,30(10):1047-1053

All traumatic and overuse injuries occurring during an average period of 4 years (2002/09) in a group of 51 currently active road top-level cyclists were retrospectively registered through clinical interviews. Average age was 25.8 years. Average training and competition period was 28.3 ± 2.4 h a week. Only 8 cyclists (15.6%) were completely free from lesions during the period of study. The remaining 43 cyclists suffered a total of 112 lesions; however, 9 out of these were unrelated to their cycling practice. These 103 cycling-related injuries include 50 (48.5%) traumatic and 53 (51.5%) overuse injuries. Twenty-eight fractures were reported, the clavicle being the most frequently affected bone (11 cases). The 68.5% of overuse injuries were located in the lower limbs. Most overuse injuries (89.6%) occurred during the training period. According to the injury abbreviated scale (AIS), severe lesions were only found in 4 cases (8% of traumatic injuries). Overall injury rates were 0.50 per racer/year, 2.02 per studied racer, and 0.007 per 1000 km of training and competition. Active professional top-level cyclists are exposed to a high injury risk. According to the scarce previously published data the current study provides relevant information on the injury occurrence of still active top-level road cycling.  相似文献   

Effect of positioning on the accuracy of decision making of association football top-class referees and assistant referees during competitive matches   总被引：1，自引：1，他引：0  

J Mallo  PG Frutos  D Juárez  E Navarro 《Journal of sports sciences》2012,30(13):1437-1445

Abstract The aim of this study was to examine the effect of positioning on the correctness of decision making of top-class referees and assistant referees during international games. Match analyses were carried out during the Fédération Internationale de Football Association (FIFA) Confederations Cup 2009 and 380 foul play incidents and 165 offside situations were examined. The error percentage for the referees when indicating the incidents averaged 14%. The lowest error percentage occurred in the central area of the field, where the collaboration of the assistant referee is limited, and was achieved when indicating the incidents from a distance of 11-15?m, whereas this percentage peaked (23%) in the last 15-min match period. The error rate for the assistant referees was 13%. Distance of the assistant referee to the offside line did not have an impact on the quality of the offside decision. The risk of making incorrect decisions was reduced when the assistant referees viewed the offside situations from an angle between 46 and 60°. Incorrect offside decisions occurred twice as often in the second as in the first half of the games. Perceptual-cognitive training sessions specific to the requirements of the game should be implemented in the weekly schedule of football officials to reduce the overall error rate.  相似文献   

Active relatives and health-related physical fitness in European adolescents: The HELENA Study     

M Martín-Matillas  FB Ortega  JR Ruiz  D Martínez-Gómez  G Vicente-Rodríguez  A Marcos  L Béghin  A Kafatos  M González-Gross  M Zaccaria  D Molnár  S De Henauw  M Sjöström  LA Moreno  MJ Castillo On Behalf Of The Helena Study 《Journal of sports sciences》2012,30(13):1329-1335

Abstract High physical fitness in childhood and adolescence is positively associated with favourable health-related outcomes. Our aim was to examine the relationship between relatives' (father, mother, brother, sister, and best friend) physical activity engagement and encouragement on adolescents' physical fitness. Adolescents were part of the HELENA study, a multi-centre study conducted in 10 cities from nine European countries in 2006-2008. Participants were 3288 adolescents (48% boys, 52% girls) aged 12.5-17.5 years with valid data on at least one of the three fitness variables studied: muscular strength (standing long jump), speed/agility (4×10 m shuttle run), and cardiorespiratory fitness (20 m shuttle run). The adolescents reported their relatives' physical activity engagement and encouragement. Analysis of covariance showed that relatives' physical activity engagement (father, mother, brother, and best friend) was positively related to cardiorespiratory fitness (P?相似文献   

Fading memory and stability     

Guoqiang Zang  Pablo A. Iglesias   《Journal of The Franklin Institute》2003,340(6-7):489-502

The conditions under which discrete-time nonlinear affine systems possess fading memory are explored. A sufficient condition is given based on discrete-time Lyapunov theory; whereas a necessary condition is provided based on the relationship between the stability and the continuity of this system.  相似文献   

Online educational videos according to specific didactics: the case of mathematics / Los Vídeos educativos en línea desde las didácticas específicas: el caso de las matemáticas     

Pablo Beltrán-Pellicer  Belén Giacomone  María Burgos 《Cultura y Educación》2013,25(4):633-662

Abstract

The vast number of online educational videos available at the moment has generated an emerging area of research concerning their level of suitability. This study considers the epistemic quality of educational videos on mathematics, focusing on the specific content of directly proportional distributions. A qualitative study is used, based on the application of theoretical and methodological tools from the onto-semiotic approach to knowledge and mathematics instruction, principally the notion of epistemic suitability and the identification of algebraic levels. The sample consists of the 31 most popular videos in Spanish on YouTube? on directly proportional distributions. Analysis reveals interesting results on these kinds of resources. In general, it is observed that they are weak in epistemic suitability, which does not seem to affect their level of popularity. Moreover, the existence of videos with inaccurate arguments or incorrect procedures, together with the diversity of algebraic levels used, indicates that teachers should be careful when selecting them and only recommend those that better suit their students’ needs.  相似文献   

Los audiovisuales en la educación     

Lola Abelló  Pablo Del Rio 《Cultura y Educación》2013,25(14)

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¿Usos cotidianos o usos enlatados? Enseñar y evaluar la lectoescritura a sujetos reales y mentes flexibles     

Pablo del Río 《Cultura y Educación》2013,25(19-20):5-24

En el campo del lenguaje y la lectoescritura, la renovación educativa parece estar situándose en la batalla por el diseño abierto y la evaluación informal. En este artículo se propone un modelo teórico para la lectoescritura flexible que pueda soportar las posibilidades que se abren y evitar los inconvenientes que amenazan a los actuales métodos informales de renovación a los que está dedicado el tema central de este número.  相似文献   

‘Teaching between the lines’: discussing,interpreting and writing stories together / ‘El aula entre líneas’: hablamos,interpretamos y escribimos historias conjuntamente     

Belén Izquierdo-Magaldi  Pilar Lacasa  Héctor del Castillo 《Cultura y Educación》2013,25(3):535-556

Abstract

The purpose of our study was to carry out a writing workshop in a collaborative setting in which the teacher and the 14 year-old students made up stories while being observed by a researcher. We used a qualitative methodology similar to the Ethnography of Communication and Discourse Analysis, in which narrative and analytical analyses are seen as complementary, in order to interpret all aspects of the participants’ activities. The analysis of the conversations held in the different working situations defined by the presence or absence of the teacher shows that the guiding role played by the teacher is essential in terms of the students’ acquisition of knowledge concerning the generalization of meanings, the organization of social relations and the structuring of the task. Likewise, within a group of peers involved in working towards a common goal, one or several of them tend to take on the guiding role when the teacher is not present.  相似文献