A behaviour‐genetic analysis of orthographic learning,spelling and decoding

As part of a longitudinal twin study of literacy and language, we conducted a behaviour‐genetic analysis of orthographic learning, spelling and decoding in Grade 2 children (225 identical and 214 fraternal twin pairs) in the United States and Australia. Each variable showed significant genetic and unique environment influences. Multivariate analyses revealed very high genetic correlations among the variables, indicating that the same genes are involved in their aetiology. These genes are partly independent of those contributing to intelligence. A further analysis indicated that the covariation between decoding and orthographic learning is mediated by shared genes rather than by a direct causal path. The authors argue that a learning parameter, most directly assessed by orthographic learning in this study, underlies all three literacy variables. The results are also discussed in relation to Share's self‐teaching hypothesis, which may require modification.     

语言正在全球5个热点地区快速消亡

语言学家警告说,每两个星期就至少有一种语言从地球上消亡。语言消亡这种现象是语言自身进化中的一个阶段还是退化中的一个阶段?在一些语言消亡的同时,一些新的语言也在出现。我们要尽可能地挽救语言消亡给人类文化带来的损失,但就语言本身来说,我们也不需要过分恐慌……     

Der Mathematikunterricht der PISA-Schülerinnen und -Schüler

Der Beitrag besch?ftigt sich mit dem Mathematikunterricht der PISA-Schülerinnen und -Schüler in Deutschland und berichtet über Ergebnisse aus einer Zusatzstudie zu PISA 2003. Aufbauend auf der mathematik-didaktischen Rahmenkonzeption von PISA, die Unterricht als Gelegenheitsstruktur für verst?ndnisvolle Lernprozesse versteht, wurden Schülerinnen und Schüler und ihre Mathematiklehrkr?fte zu Merkmalen der Unterrichtsqualit?t befragt. Es zeigen sich schulformspezifische Unterrichtskulturen: Ein kognitiv aktivierender Umgang mit mathematischen Inhalten ist eher in Gymnasien zu beobachten, w?hrend vor allem in Hauptschulen die Unterrichtsform mit geringem kognitiven Gehalt und ausgepr?gter Unterstützung überwiegt. Dennoch wird die Angebotsstruktur des Mathematikunterrichts von Jugendlichen an Hauptschulen positiv beurteilt, w?hrend Gymnasiasten ihren Unterricht eher kritisch bewerten. Diese Differenzen sind vor allem durch Unterschiede in der individuellen Lernunterstützung durch die Lehrkr?fte zu erkl?ren, welche von Schülerinnen und Schülern an Hauptschulen als besonders ausgepr?gt, an Gymnasien eher als gering beschrieben wird.     

Prediction of elementary mathematics grades by cognitive abilities

European Journal of Psychology of Education - In the present study, the relationship between the mathematics grade and the three basic cognitive abilities (inhibition, working memory, and...     

水文预报的时间序列神经网络模型

时间序列分析在水文预报中起重要作用 ,其关键是要建立一个合适的预报模型 .文章提出基于 BP算法的单输出和多输出水文预报时间序列神经网络模型 ,克服了以往多种基于随机分析预报模型的缺点 ,不仅能实现快速灵活的信息处理 ,而且具有很强的非线性映射和自学习、自适应能力 ,这为更精确描述复杂非线性水文过程提供了可能 .通过对历史数据的学习 ,模型可对水文径流量时间序列进行预报 ,两个实例分析表明模型的可行性和有效性     

Impairments in learning due to motivational conflict: situation really matters

Although many theories mention distractions by conflicting alternatives as a problem for self-regulation, motivational conflicts are rarely considered when explaining impairments in learning. In two studies, we investigate the assumption of motivational interference theory that students show different amounts of impairments in learning depending on the presence and motivational strength of conflicting alternatives. In Study 1 (N?=?221), the subjective value attributed to a respective alternative in a study–leisure conflict scenario partially accounted for differences in self-regulated learning while controlling for interindividual differences. Study 2 (N?=?112) demonstrated that this pattern applies to both when the respective alternatives refer to ‘liking to’ (want conflicts) and ‘having to’ (should conflicts) do something. Moreover, it is demonstrated that impairments due to motivational conflict are higher than impairments inherent in the studying activity itself (baseline). The results emphasise the importance of concurring action alternatives for explaining difficulties in self-regulated learning.     

Kinematic differences of elite and high-performance tennis players in the cross court and down the line forehand

This study identified and compared the full body kinematics of different skill levels in the forehand groundstroke when balls were hit cross court and down the line. Forty-three three-dimensional retroreflective marker trajectories of six elite and seven high-performance players were recorded using an eight-camera 400 Hz, Vicon motion analysis system. The six highest horizontal velocity forehands with reliable kinematics of all participants were analysed for each specific situation (a total of 156 analysed shots). Significant differences (p < 0.01) and large effect sizes were observed between elite and high-performance players in linear velocity of the shoulder (2.0 vs. 1.2 m/s), angular velocity of the pelvis (295 vs. 168 degrees/s), and angular velocity of the upper trunk (453 vs. 292 degrees/s) at impact. The elite group showed a tendency towards higher racquet velocities at impact (p < 0.05). No significant differences were found in angular displacement of the racquet, hip alignment, or shoulder alignment at the completion of the backswing; nor did angular displacement vary significantly at impact. Irrespective of the group, different shoulder, hip, and racquet angles were found at impact, depending on the situation. The results should assist coaches when striving to improve their players' forehand.     

Under the radar: Industry entry by user entrepreneurs

We inductively develop a model of the commercialization process for new products or services user entrepreneurs undertake when entering an industry while drawing on proprietary technology developed in another industry. Extending the growing field of user entrepreneurship, we identify a two-phase approach to industry entry by user entrepreneurs who start “under the radar” of incumbent firms, gain experience, attract a first potential customer base, and then, in a second phase, engage in commercialization. During this process, a community of fellow users is of major importance for the entrepreneur, serving as a knowledge pool for skills development and experimentation with different commercialization paths. We study a nascent group of firms founded by users of video games who became entrepreneurs on entering the animation industry by producing Machinima, a new film genre characterized by shooting film in video games. We explain how user entrepreneurs gain access to complementary assets (video games) for their new use (shooting film), how they deal with intellectual property issues when using other firms’ assets, and how user entrepreneurs combine domain knowledge about film production with their experience in video games and the art of Machinima. Our propositions hold implications for management and policy.