The kinematic differences between off-spin and leg-spin bowling in cricket     

Aaron J. Beach  René E. D. Ferdinands  Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):295-313

Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling.  相似文献   

Perceived health problems in swimmers according to the chemical treatment of water in swimming pools     

Álvaro Fernández-Luna  Pablo Burillo  José Luis Felipe  Julio del Corral  Jorge García-Unanue  Leonor Gallardo 《European Journal of Sport Science》2016,16(2):256-265

The objective of this study was to determine which chemical treatment used for disinfecting water in indoor swimming pools had the least impact on users' perceptions of health problems, and which generated the greatest satisfaction with the quality of the water. A survey on satisfaction and perceived health problems was given to 1001 users at 20 indoor swimming pools which used different water treatment methods [chlorine, bromine, ozone, ultraviolet lamps (UV) and salt electrolysis]. The findings suggest that there is a greater probability of perceived health problems, such as eye and skin irritation, respiratory problems and skin dryness, in swimming pools treated with chlorine than in swimming pools using other chemical treatment methods. Pools treated with bromine have similar, although slightly better, results. Other factors, such as age, gender, time of day of use (morning and afternoon) and type of user (competitive and recreational), can also affect the probability of suffering health problems. For all of the above, using combined treatment methods as ozone and UV, or salt electrolysis produces a lower probability of perceived health problems and greater satisfaction.  相似文献   

Competencies evaluation in engineering programmes     

Mario F. Letelier  José A. Herrera  Andrea M. Canales  Rosario Carrasco  Lorena L. López 《European Journal of Engineering Education》2003,28(3):275-286

Results are reported in this paper from a study aimed at evaluating significant competencies in final-year students of some engineering programmes in Chile. The study was carried out by a group of eight universities that were interested in exploring ways to assess learning outcomes such as those demanded by the recent Chilean accreditation system. The authors actively participated in all stages of the study, contributing directly to the design, application and results evaluation of some tests. A sample of 150 students was tested, under conditions that guaranteed the comparability of results. In this paper the authors present results relating to the evaluation of effective communication. The study was backed up by a conceptual model and some hypotheses that are explained and discussed in this work.  相似文献   

AECT Internship Programs - Developing Leaders for Tomorrow     

J. José Cortez 《TechTrends》2006,50(1):6-8

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“Lo que yo en realidad quería hacer”: Rationales of Latina/o DACA Recipients for Pursuing Careers as Teachers     

García  José 《The Urban Review》2020,52(5):830-852

The Urban Review - The decision to rescind Deferred Action for Childhood Arrivals (DACA) will have major repercussions amongst beneficiaries, especially in terms of employment. One of the sectors...  相似文献   

Metaphors we’re colonised by? The case of data-driven educational technologies in Brazil     

Giselle Martins dos Santos Ferreira  Luiz Alexandre da Silva Rosado  Márcio Silveira Lemgruber  Jaciara de Sá Carvalho 《Learning, Media and Technology》2020,45(1):46-60

ABSTRACT

This article discusses issues concerning the spread of data-driven educational technologies in Brazil. Here, as elsewhere, educational technology continues to be promoted optimistically as the bearer of a panacea for historically-rooted social problems. Whilst some of these technologies have indeed contributed to important widening-participation programmes in the last two decades, widespread advocacy of technological ‘solutionism’, reflected in gradually stronger policy demands for efficiencies to be improved through ‘innovation’, has supported a relentless marketisation of the country’s educational systems. As transnational corporations position themselves to take control of key areas of these systems, threatening to restructure the whole sector, data-driven educational technologies provide the latest example in a series of ‘new’ ideas offered in an ever-expanding market. Based on the notion of ‘conceptual metaphors’, which encapsulate specific ways of perceiving, thinking and relating with the world, this article examines key metaphors underpinning discourses surrounding data-driven educational technologies in Brazil. In particular, the article analyses ways in which these specific metaphors may be promoting perspectives that ignore difference and obscure broader questions concerning education, thus contributing to the reproduction of previously existing problems and supporting new forms of colonisation.  相似文献   

The Nature of Scientific Practice and Science Education     

Antonio García-Carmona  José Antonio Acevedo-Díaz 《Science & Education》2018,27(5-6):435-455

There is, broadly speaking, an agreement within the international science education community that comprehension of the nature of science (NOS) should be a key element in the scientific literacy of citizens. During the last few decades, several didactic approaches have emerged concerning what and how to teach NOS. Also, one of the basic objectives of science education is for students to become familiar with the skills typical of scientific practice; however, there is little reference to their need to also acquire meta-knowledge about scientific practice (i.e., an understanding of the nature of scientific practice). Among other reasons, this may be due to NOS being essentially identified in most of the predominant proposals with the nature of scientific knowledge. But why not plan the teaching of science to be in tune with real scientific practice for students to learn about the nature of scientific practice at the same time as they are learning science? The answer to this question has given rise to a proposal grounded in ten essential pedagogical principles for the teaching and learning of science in secondary school. These are the principle of formulating questions, the principle of creativity and imagination, the principle of experimentation, the principle of procedural diversity, the principle of errors as opportunity, the principle of modeling, the principle of cooperation and teamwork, the principle of argumentation and discussion, the principle of communication, and the principle of evaluation. The purpose of this article is to present the justification and fundaments of these principles.  相似文献   

Pedro Gutiérrez Bueno’s Textbooks: Audiences, Teaching Practices and Chemical Revolution     

José Ramón Bertomeu Sánchez  Antonio García Belmar 《Science & Education》2006,15(7-8):693-712

Pedro Gutiérrez Bueno wrote two editions of a chemistry textbook between 1788 and 1802. The paper offers a comparative view of both editions taking into account Gutiérrez Bueno’s biography, his intended audience and the changes related to the so-called chemical revolution. Some conclusions are at odds with common images about scientific revolutions and the role of textbooks in science. The analysis aims to shed some light on the multiple historical forces shaping textbooks and the way in which scientific change is assimilated by their writers. This research was partially supported by the program BHA2002-04611-CO3-02  相似文献   

Books and articles of academic interest     

Antonio Gómez Skarmeta  Pedro García López  Jesús Egea Payá  José Meseguer Navarro  Tomás Jiménez García 《Academic Questions》1994,8(1):91-92

Books and articles of academic interest  相似文献   

The second year of life as a developmental turning point: Implications for «sensitive» caretaking     

André Vyt 《European Journal of Psychology of Education - EJPE》1989,4(2):145-158

In the context of the transactional view on development, important changes in the second year of life are highlighted which demand parental adaptations in caregiving practice. The discontinuous growth of enriched cognitive functions in the toddler, as exemplified by Piagetian theory on development of intentionality and symbolic thinking and by recent findings about the emergence of self-awareness and mastery-motivation, meshes with changes in caregiving dimensions. The caregiver, seen as a catalyst for the development of cognitive and social competence must adjust himself to the developmental tasks the infant is coping with. The concept of sensitivity is examined in terms of two important aspects: the social and the didactic. From a Vygotskian standpoint, didactic strategies are very important for cognitive competence. Parents have to facilitate self-initiated learning and to adjust to the infant’s increasing cognitive functions. The influence of a didactic «matching» on overall parent-infant interaction quality, and especially on the quality of attachment, is stressed.  相似文献