The influence of moment of inertia on baseball/softball bat swing speed

The speed at which a player can swing a bat is central to the games of baseball and softball, determining, to a large extent, the hit speed of the ball. Experimental and analytical studies of bat swing speed were conducted with particular emphasis on the influence of bat moment of inertia on swing speed. Two distinct sets of experiments measured the swing speed of colege baseball and fast-pitch softball players using weighted rods and modified bats. The swing targets included flexible targets, balls on a tee and machine pitched balls. Internal mass alterations provided a range of inertial properties. The average measured speeds, from 22 to 31 m s⁻¹, are consistent with previous studies. Bat speed approximately correlates with the moment of inertia of the bat about a vertical axis of rotation through the batter's body, the speed generally decreasing as this moment of inertia increases. The analytical model assumes pure rotation of the batter/bat system about a vertical axis through the batter's body. Aerodynamic drag of the batter's arms and the bat is included in the model. The independent variable is bat moment of inertia about the rotation axis. There is reasonable agreement between the model and the measured speeds. Detailed differences between the two suggest the importance of additional degrees of freedom in determining swing speed.     

CERN document server: Document management system for grey literature in a networked environment

Conclusion In this paper we briefly described the current status of research in the field of digital libraries interoperability, mainly with respect to federated data processing such as permitted within the Open Archive Initiative framework. We then presented the CERN Document Server Software suite that is a free software package main-tained by CERN providing an online digital library solution for mid- to large-sized document repositories. The set of CDSware modules was described and the differ-ences with other existing tools briefly mentioned. Finally we have mentioned a typical usage statistics illustrating the scope of grey literature and networked con-ditions of the CERN Document Server. We pointed out that the current trend in grey literature management goes toward institutional repositories build upon the distributed and federated model. Further research is going on within the CDS collaboration in this area, focused particularly on (i) semantic interoperability using ontologies in distributed and federated data processing and (ii) ranking technologies when searching grey literature in OAI compliant repositories.     

Ethnic and regional influences on teachers' evaluations of oral answers

Tape recordings were made of six white and six black ninth-grade northern boys speaking identically worded answers to typical school questions. Black students were given significantly higher grades than white students by 56 white and 50 black southern teachers. Black teachers gave significantly higher grades than white teachers, but no significant interaction was found between students' and teachers' ethnic group. The study is a partial replication of a previous study in which it was found that black students were given significantly lower grades than white students by northern white teachers.     

Do you Mini-Med School? Leveraging library resources to improve Internet consumer health information literacy

Popular for engaging public interest in medical science while promoting health awareness, Mini-Med School (MMS) programs also afford important if largely unrealized opportunities to improve the health information literacy of attendees. With a growing population using the Internet to make health decisions, needed venues for improving Internet Consumer Health Information (CHI) literacy may be found in the MMS platform. Surveyed directors of MMS programs understand the need to include CHI, and successful programs at SUNY Stony Brook and elsewhere demonstrate the potential for collaboration with affiliated health sciences libraries to integrate CHI instruction into MMS curricula.     

Impact forces and neck muscle activity in heading by collegiate female soccer players

Three soccer header types (shooting, clearing and passing) and two heading approaches (standing and jumping) were manipulated to quantify impact forces and neck muscle activity in elite female soccer players. The 15 participants were Division I intercollegiate soccer players. Impact forces were measured by a 15-sensor pressure array secured on the forehead. The electromyographic (EMG) activity of the left and right sternocleidomastoid and trapezius muscles was recorded using surface electrodes. Maximum impact forces and impulses as well as the EMG data were analysed with separate repeated-measures analyses of variance. Impact forces and impulses did not differ among the header types or approaches. Higher values were found for jumping versus standing headers in the mean normalized EMG for the right sternocleidomastoid. In addition, the integrated EMG was greater for the right sternocleidomastoid and right and left trapezius (P < 0.05). The sternocleidomastoid became active earlier than the trapezius and showed greater activity before ball contact. The trapezius became active just before ball contact and showed greater activity after ball contact. The increased muscle activity observed in the neck during the jumping approach appears to stabilize the connection between the head and body, thereby increasing the stability of the head-neck complex.     

Peer‐Mediated Instruction in Inclusive Secondary Social Studies Learning: Direct and Indirect Learning Effects

Ten inclusive middle school social studies classes, including 133 general education students, and 24 students with mild disabilities (21 with learning disabilities and 3 with emotional disabilities), were assigned at random to a traditional instruction condition, or an experimental condition involving classwide peer tutoring with specialized materials and parent training. After 18 weeks of instruction, posttest data revealed that students in the experimental condition gained significantly more than students in the traditional instruction condition. These effects were observed on content included in the tutoring intervention, as well as on related content that was taught but not included in the tutoring intervention. Results are discussed within the context of recent research on inclusive secondary content area instruction.     

服务业创新的新熊彼特定义：基于新分类法的概念探讨

创新是一项复杂的过程并具有多面性。在众多以创新与生产率之间联系为主题的研究中，由于数据限制，往往只采用单一指标来测度创新。本文对这种方式提出了质疑，认为这种研究方法可能会系统地偏向于某类经常通过参与创新活动以达到各种商业目的的公司或产业。为了更好地测度创新，本文介绍了一种创新索引，即以潜变量模型为基础的含有多项创新指标的线性指标组合。这一尝试得到加拿大制造业公司的大量微观数据组合的支持。