Cultured pearls—commercialised biomineralisation

At the turn of the last century there was an ever increasing world demand for pearls while at the same time their known fishing grounds were becoming exhausted. Some way of artificially increasing their production was obviously desirable, and the problem attracted considerable effort. It was an attempt to exploit a scientifically poorly understood phenomenon, and it is interesting, in retrospect, to relate these attempts to recent concepts of biomineralisation. Pearls are, of course, the layers of aragonitic calcium carbonate secreted by molluscs.     

Relationships between scores on Stanford-Binet IV and Wechsler preschool and primary scale of intelligence

A kindergarten class of 9 boys and 11 girls took the 1986 Stanford-Binet Intelligence Scale (Fourth Edition) and the Wechsler Preschool and Primary Scale of Intelligence. Of 6 correlations of total scores and subtest pairs, only the correlation of total scores was statistically significant (p<.01).     

The effect of towing a range of relative resistances on sprint performance

The aim of this study was to compare sprint performance over 10 and 20?m when participants ran while towing resistances, weighing between 0 and 30% of body mass. The sample of 33 participants consisted of male rugby and soccer players (age 21.1?±?1.8 years, body mass 83.6?±?13.1?kg, height 1.82?±?0.1?m; mean?±?s). Each participant performed two sets of seven sprints over 20?m using a Latin rectangular design. The times were recorded at 10 and 20?m using electronic speed gates. The sprints of 13 players were video-recorded to allow calculation of stride length and frequency. For both sprints, a quadratic relationship was observed between sprint time and resistance as sprint time increased from 2.94?s to 3.80?s from 0 to 30% resistance. This relationship was statistically significant but considered not to be meaningful for performance because, over the range of resistances used in this study, the quadratic model was never more than 1% (in terms of sprint time) from the linear model. As resistance increased, the stride length shortened, with mean values of 1.63?±?0.13?m at 0% body mass and 1.33?±?0.13?m at 30% of body mass. There was no significant change in stride frequency with increasing resistance. The results show that in general there is an increase in sprint time with an increase in resistance. No particular resistance in the range tested (0?–?30%) can be recommended for practice.     

为肯尼亚青年谋求STEM教育的平等机会

肯尼亚人口中18岁以下的青少年占50％,他们是肯尼亚社会中一股重要而活跃的力量,大力发展青少年教育是促进发展的有效方式。肯尼亚科学中心是一所筹建中的STEM教育机构,旨在为所有青少年提供平等的教育机会,并接受STEM教育方面的启迪。本文介绍了建设和发展肯尼亚科学中心的各种工作方式,期望能够借鉴国际上其他科学中心的经验,以达成独具特色的发展目标。     

Peer review: still king in the digital age

The article presents one of the main findings of an international study of 4,000 academic researchers that examined how trustworthiness is determined in the digital environment when it comes to scholarly reading, citing, and publishing. The study shows that peer review is still the most trustworthy characteristic of all. There is, though, a common perception that open access journals are not peer reviewed or do not have proper peer‐review systems. Researchers appear to have moved inexorably from a print‐based system to a digital system, but it has not significantly changed the way they decide what to trust. They do not trust social media. Only a minority – although significantly mostly young and early career researchers – thought that social media are anything other than more appropriate to personal interactions and peripheral to their professional/academic lives. There are other significant differences, according to the age of the researcher. Thus, in regard to choosing an outlet for publication of their work, young researchers are much less concerned with the fact that it is peer reviewed.