An examination of slo-pitch pitching trajectories

Many slo-pitch coaches and players believe that generating spin on a ball can affect its trajectory. The influence of air resistance on a ball that is thrown at a moderate speed and spin is unclear. The aim of this study was to examine the influence of spin on the ball's trajectory in slo-pitch pitching using both experimental results and ball flight simulations. Fourteen pitchers participated in the study, each of whom threw five backspin and topspin pitches each. Data were collected using standard three-dimensional videography. The horizontal velocity, vertical velocity, angular velocity, release height, and horizontal displacement of the backspin pitches were significantly higher than those of the topspin pitches. The ball flight simulations were developed to examine the influence of the ball spin, and it was concluded that the spin of the ball had a significant effect on the ball's vertical and horizontal displacements. Furthermore, our results suggest that a backspin pitch that reaches the maximum height allowable and lands in the front edge of the strike zone has the steepest slope. The present results add to our understanding of projectile motion and aerodynamics.     

CONNECTIONISM AND THE EMERGENCE OF KNOWLEDGE

Procedures for creating used by connectionist networks with hidden units are analyzed. With these networks it is possible to create by modification of the inputs, by modification of collector properties, by modification of connections between units and variation of thresholds of activation, by modification of constraints imposed on the network, by creation of new hidden units or by creation of new outputs. The interest of connectionist networks is in simulating various processes to allow analysis of modifications that are efficient and capable of concretizing the consequences of choices. Networks must be designed as tools capable of helping formalize problems, and not as replicas of cognitive processes.     

谈欧洲教育史研究方法

本文围绕近年欧洲教育史研究方法的变化这一主题,首先指出在国家众多、国情各异的欧洲,教育史学家在研究方法方面的差异和其文化专业背景及工作环境等不同有关;然后通过四个案例具体介绍欧洲教育史工作者如何运用新的史学研究方法来发掘新资料、提出新问题和拓展研究领域的;最后概要叙述史学方法最新的两大变革走向及教育史研究工作者在这种变革中应注意的问题。     

Les expéditions militaires contre Chypre (1424–1426) d’après ṢāliḤ b. YāḤya: Quelques remarques sur la marine mamelouke

Le texte rédigé par Sālih b.Yahyā constitue une source primordiale pour létude des expéditions militaires mameloukes contre Chypre entre 1424 et 1426 car l’auteur a joué un rôle principal dans la deuxième et la troisième attaque. Â la différence d'autres chroniqueurs arabes, Sālih b.Yahyā fournit des informations importantes qui permettent de reconstruire les événements et de comprendre le fonctionnement de la marine mamelouke.     

Utiliser la Dimension Europe´enne Pour Faire Sortir l'Ecole de ses Murs ou 'Extra Muros'

Five European Institutions devoted to head teacher training developed the Comenius Project 'Extra Muros' between 1996 and 1999. The general objectives were, on the one hand, understanding the importance of the educative action outside the school premises if we wanted to offer equality of opportunity to everybody, and, on the other hand, promoting the school to spread into its local area and to discover Europe. Thus, the integration of school in its territory is favoured, and the interaction of students with their peers is facilitated. The article describes in detail the organisation, development and evaluation of the project, and also the impact it caused in teachers and pupils.     

Theorising community gardens as pedagogical sites in the food movement

Community gardens are rich non-school sites of informal adult learning and education in the North American food movement. To date, however, they have seldom been the subject of research in environmental education. This paper argues that theorising on public pedagogy and social movement learning from the field of Adult Education might effectively be applied to frame the study of learning in community gardens. A brief history of community gardens in the USA is first given, followed by an overview of theory on social movement learning. A review of empirical research on the individual and collective benefits of participation in community garden initiatives is then used to illustrate the potential for research on the connection between learning and these benefits. The paper concludes with a discussion of implications for further research.     

A cross-case analysis of three Native Science Field Centers

Native Science Field Centers (NSFCs) were created to engage youth and adults in environmental science activities through the integration of traditional Native ways of knowing (understanding about the natural world based on centuries of observation including philosophy, worldview, cosmology, and belief systems of Indigenous peoples), Native languages, and Western science concepts. This paper focuses on the Blackfeet Native Science Field Center, the Lakota Native Science Field Center, and the Wind River Native Science Field Center. One of the long-term, overarching goals of these NSFCs was to stimulate the interest of Native American students in ways that encouraged them to pursue academic and career paths in science, technology, engineering, and mathematics (STEM) fields. A great deal can be learned from the experiences of the NSFCs in terms of effective educational strategies, as well as advantages and challenges in blending Native ways of knowing and Western scientific knowledge in an informal science education setting. Hopa Mountain—a Bozeman, Montana-based nonprofit—partnered with the Blackfeet Community College on the Blackfeet Reservation, Fremont County School District #21 on the Wind River Reservation, and Oglala Lakota College on the Pine Ridge Reservation to cooperatively establish the Native Science Field Centers. This paper presents a profile of each NSFC and highlights their program components and accomplishments.