PubMed, Internet Grateful Med, and Ovid: a comparison of three MEDLINE Internet interfaces

Three MEDLINE Internet interfaces are compared: PubMed, Internet Grateful Med, and Ovid MEDLINE. Although these interfaces all search MEDLINE, significant differences exist in terms of their search interfaces, presentation of results, and special features. This paper examines these variations and explores some of the advantages and disadvantages of the three interfaces.     

Student activity levels, lesson context, and teacher behavior during middle school physical education

There is little research on students' engagement in physical activity in middle school physical education (PE). We observed student activity, lesson context, and teacher behavior in 430 PE lessons taught by 126 teachers in 24 schools. Variables were analyzed by mixed-model nested analyses of covariance. Boys were more active than girls overall and during skill drills, game play, and free play. Student activity varied by lesson context, with fitness activities producing the most activity. Class size was negatively associated with student activity. Daily PE contributed a weekly total of 25 min of vigorous activity and 83 min of moderate-to-vigorous activity--much less than national objectives. Results suggest that numerous opportunities exist for increasing student physical activity during middle school PE.     

State anxiety and motor performance: testing the conscious processing hypothesis

Previous research has argued that skills acquired explicitly are more likely to fail under stressful conditions than skills that have been learned implicitly. The present study addressed an alternative explanation for the robustness under stress of implicit task performance. As implicit learners acquired the skill of golf putting while generating random letters, it is possible that they became desensitized to self-generated verbalizations and thus immune to the effects of competitive anxiety. We tested this interpretation while controlling for a further rival hypothesis generated by Eysenck's Processing Efficiency Theory. We also examined the effect of increased state anxiety on the kinematic processes underlying performance breakdowns. For task performance, we found evidence that partially supported the conscious processing hypothesis, while the results of the kinematic analysis of the putting stroke were equivocal. Analysis of self-reported effort scores provided partial support for processing efficiency theory.     

Response of males and females to high-force eccentric exercise

It has previously been shown that females incur less muscle damage than males after strenuous exercise, but limited data are available for humans. To determine possible differences between the sexes in humans, the response to high-force eccentric exercise was examined in a large sample of women (n = 83) and men (n = 82). The participants performed a bout of eccentric exercise of the elbow flexors consisting of 70 maximal repetitions. Isometric strength, resting elbow angle and muscle soreness were measured before, immediately after (except soreness) and then daily for 7 days after exercise. There was a significant loss in strength among both groups (69% for women and 63% for men) (P < 0.01) immediately after exercise; at 168 h post-exercise, women still had a 27% strength loss and men had a 24% strength loss. No significant difference in strength loss or recovery rate was found between men and women. Soreness reached peak values 32-48 h post-exercise (P < 0.01), with no significant difference between men and women. Range of motion decreased significantly until 3 days after exercise (14.6 degrees or 0.255 rad loss for women; 12.2 degrees or 0.213 rad loss for men) (P < 0.01); at 168 h post-exercise, the women and men still showed a loss of 4.8 degrees (0.084 rad) and 4.0 degrees (0.07 rad), respectively. There was a significant interaction of sex x time (P < 0.01); a post-hoc test indicated that the women experienced a greater loss in range of motion at 72 h than men and this difference was maintained to 168 h post-exercise (P < 0.01). Thus, our results do not support the contention that women have a lower response to eccentric exercise than men.     

Force production in the rugby union scrum

In this study, we examined the relationship between anthropometric, strength and power characteristics of rugby forwards, their body position when scrummaging, and their ability to apply force when scrummaging. Force applied to an instrumented scrum machine was measured for 56 players, both individually and as scrum packs. Measurements of body position for individuals were made by digitizing videotape records of the trials. Forty players subsequently had their anthropometry assessed and completed several strength and power tests. Body mass, each component of somatotype, maximal anaerobic power developed on a cycle ergometer, and isokinetic knee extension strength correlated significantly with individual scrummaging force. A regression model (P < 0.001) including body mass, mesomorphy, maximal anaerobic power and hip angle while in the scrummaging position accounted for 45% of the variance in individual scrummaging force. The packs that produced the largest scrummaging forces were, in general, characterized by a greater pack force to sum of individual force ratio than the packs producing lower forces. Our results emphasize the need for a scrum pack to develop technique and coordination as a unit to maximize scrummaging force.     

从信息传播角度看科技期刊编辑出版过程及其优化

从信息传播角度将科技期刊编辑出版过程划分为信息选择、信息加工、信息传递、传播效果检验等4个环节.分析各个环节在传播学上的本质特征,进而指出其中存在的问题及解决方法.     

学术期刊编辑应重视稿件修改说明书

为加强对作者修改稿的质量管理,不断提高刊稿质量,认为学术期刊编辑应重视作者修改稿的修改说明书,并阐明其目的意义、要求和原则及应注意的问题.     

图书情报学期刊网络资源利用状况探析

本文采用信息计量学方法，对我国图书情报学期刊中网络引文的数量和特征进行了详细的统计、分析，发现了本学科常用的网络资源，揭示了我国图书情报学期刊对网络资源的利用情况。     

网络资源引用规范研究

我国学术期刊中对网络资源的引用和著录还存在很多问题。文章认为应对网络资源的引用内容作出限定,并提出了网络引文的引用原则,利用文献注对那些不适合作为引文的网络资源进行补充著录或说明。通过对2005年新版国家标准的分析和国外著名文体规范的对比研究,归纳总结新规则的优劣,提出了改善我国网络引文著录现状及加强我国网络资源引用规范的建议。     

网络环境中个性化推荐系统研究*

提出一个结合本体论及通用个人资料的个性化推荐模式。首先以网络分类服务作为本体论来解释用户的网络浏览行为，以此挖掘用户的偏好；其次，利用Web使用挖掘技术过滤多余的浏览记录，增强个性化的准确度；最后，利用本体论的层次结构特点，从用户偏好类别中挖掘其潜在偏好，产生符合用户特征的通用个人资料。