最佳角度——45°

读书的时候,一位女生坐在我的45°斜对面,我经常不经意地瞄她一眼,觉得她是那么美,于是我就经常瞄一瞄她,那是一种极大的享受。后来我才知道,原来45°是最美的角度。建设技术人员把楼梯建成45°角或接近45°的形状,因为这是最稳定的形状,不仅看起来舒服,而     

The effect of microlevel and macrolevel signaling on learning with 360° videos

The application of 360° videos raised the attention of educators and researchers, as it appears to be an approachable option to mediate complete environments in educational settings. However, challenges emerge from the perspective of educational psychology. Learning irrelevant cognitive strains might be imposed because it is necessary to navigate through spherical material. However, these potential downsides could be compensated for using signaling techniques. In a two (macrolevel vs. no macrolevel signaling) × two (microlevel vs. no microlevel signaling) factorial between-subjects design plus control group, 215 fifth-and sixth-grade students will watch a 360° video about visual and behavioral characteristics of animals. Learning outcomes, cognitive load, disorientation, and presence will be investigated. It is expected that macrolevel signaling will enhance learning and presence and reduce cognitive load and disorientation. Microlevel signaling will have comparable advantages, but these effects will be more pronounced when macrolevel signaling is implemented.     

光栅朝向分辨学习中存在关于45°对角线对称的镜像迁移

采用光栅朝向分辨任务来探讨视知觉学习中是否存在关于45°对角线对称的镜像迁移现象.训练被试分辨15°或75°朝向3或5d,每天约1h,训练前后测量15°、75°、45°朝向的分辨阈值.通过训练,训练朝向(15°或75°)的阈值下降,该学习效应没有迁移至45°朝向,但基本迁移到关于45°对称的朝向(75°或15°)上.这提示,视知觉学习可能发生在中间视皮层,该皮层同时具有一定的朝向特异性和关于45°对角线对称的镜像迁移性.     

光栅朝向分辨学习中存在关于45°对角线对称的镜像迁

采用光栅朝向分辨任务来探讨视知觉学习中是否存在关于45°对角线对称的镜像迁移现象。训练被试分辨15°或75°朝向3或5天,每天约1小时,训练前后测量15°、75°、45°朝向的分辨阈值。通过训练,训练朝向（15°或75°）的阈值下降,该学习效应没有迁移至45°朝向,但基本迁移到关于45°对称的朝向（75°或15°）上。这提示,视知觉学习可能发生在中间视皮层,该皮层同时具有一定的朝向特异性和关于45°对角线对称的镜像迁移性     

360°-multiple object tracking in team sport athletes: Reliability and relationship to visuospatial cognitive functions

IntroductionIn team sports, the ability to visually track the movements of teammates and opponents simultaneously is a critical aspect of success. In sports psychology, this ability can be examined with the help of the multiple object tracking paradigm. The current study investigated the relationship between task performance in a novel 360°-multiple object tracking task and visuospatial cognitive functions as well as the reliability of the task.MethodsIn a sample of 153 team sport athletes the relationships between performance in the 360°-multiple object tracking task and performance in a spatial attention task, a spatial working memory task, and a fluid intelligence task at a first time of measurement were investigated. Additionally, at a second time of measurement the test-retest reliability of the 360°-multiple object tracking task was measured over a six-week interval in a subsample of 65 athletes.ResultsThe expected significant correlations between the performance in the 360°-multiple object tracking task and the tasks measuring spatial attention and working memory were observed. Test-retest reliability analysis indicated a good reliability of the procedure.ConclusionsThe results of this study demonstrate that the novel 360°-multiple object tracking task allows the reliable assessment of visuospatial cognitive performance of athletes in a dynamic 360°-environment.     

纪录片中的音乐:一种符号学解读——以纪录片《180°以南》为例

纪录片是影像艺术和声音艺术的结合体,纪录片的音乐在完成叙事结构、情节分析、情感传递、意蕴表达时发挥着越来越重要的作用,因此对纪录片音乐运用的研究尤为重要。结合纪录片《180°以南》,运用符号学的两个理论来解读纪录片的音乐,力争从外延与内涵、聚合体与组合段两个方面展开对纪录片音乐的分析,找寻纪录片音乐运用的规律、方法与规范,最大限度地发挥音乐在纪录片创作中的多重作用。     

Perceptual-cognitive performance of youth soccer players in a 360°-environment – Differences between age groups and performance levels

IntroductionAn important requirement for soccer players is the accurate and rapid processing of dynamic and complex visual scenes. Therefore, in high-level youth soccer the players’ perceptual-cognitive skills are highly relevant from a scientific and practical point of view. The aim of the present study was to investigate differences in perceptual-cognitive performance between youth soccer players of different age groups and soccer performance levels in a dynamic 360°-environment.MethodsIn a sample of 292 elite and sub-elite youth soccer players from the age groups U12–U23, perceptual-cognitive skills were assessed using a 360°-multiple object tracking task. An 8 × 2 (age group x performance level) analysis of variance (ANOVA) was conducted to examine the effects of age group and soccer performance level on performance in the task.ResultsThe analyses revealed a significant main effect of age group. Post hoc analyses showed that youth players belonging to the older age groups (U16, U17, U19, and U23) performed significantly better in the 360°-multiple object tracking task than players of the youngest age group (U12). Yet no significant age-related differences could be found from age group U16 on. Furthermore, there was a significant effect of soccer performance level on the 360°-multiple object tracking performance in favor of the elite players. Significant differences between elite and sub-elite players within the same age group were only present in the highest age groups U19 and U23.ConclusionsThe results suggest that in a dynamic 360°-environment highly talented youth soccer players show better perceptual-cognitive performance with increasing age. Furthermore, elite youth players exhibit distinctive perceptual-cognitive abilities particularly at the highest age groups. These findings provide interesting implications for science and practice regarding the perceptual-cognitive skills of talented soccer players and their role in talent development.     

Self-diffusion activation energies in α-Al2O3 below 1000°C – measurements and molecular dynamics calculation

Results from impedance spectroscopy measurements at temperatures between 400 and 1000°C, for single crystal and highly pure and dense polycrystalline α-Al₂O₃ samples with well-defined grain size, are compared with that from molecular dynamics calculation. Between 650 and 1000°C, the measured activation energy for conductivity is 1.5?eV for the single crystal, and increases from 1.6 to 2.4?eV as the grain size decreases from 15 to 0.5?µm. The molecular dynamics calculation leads to the conclusion that the self-diffusion activation energy is about 1.5?eV for O and 1.0?eV for Al in single crystal α-Al₂O₃. The much higher mobility of O ions makes the O ions responsible for the conductivity of the single crystal oxide. It seems that the grain boundary leads to an increase in the activation energy. However, the quantitative influence of grain boundary still needs to be explained. Between 400 and 650°C, the measured activation energy is about 1.0?eV and independent of the grain size.     

Training 90° bimanual coordination at high frequency yields dependence on kinesthetic information and poor performance of dyadic unimanual coordination

Two groups of participants were trained to be proficient at performing bimanual 90° coordination either at a high (2.5 Hz) or low (0.5 Hz) frequency with both kinesthetic and visual information available. At high frequency, participants trained for twice as long to achieve performance comparable to participants training at low frequency. Participants were then paired within (low-low or high-high) or between (low-high) frequency groups to perform a visually coupled dyadic unimanual 90° coordination task, during which they were free to settle at any jointly determined frequency to synchronize their rhythmic movements. The results showed that the coordination skill was frequency-specific. For dyads with one or both members who had learned the 90° bimanual coordination at low frequency, the performance settled at a low frequency (≈0.5 Hz) with more successfully synchronized trials. For dyads with both members who had learned the 90° bimanual coordination at high frequency, they struggled with the task and performed poorly. The dyadic coordination settled at a higher frequency (≈1.5 Hz) on average, but with twice the variability in settling frequency and significantly fewer synchronized trials. The difference between the dyadic coordination and bimanual tasks was that only visual information was available to couple the movements in the former while both kinesthetic and visual information were available in the latter. Therefore, the high frequency group must have relied on kinesthetic information to perform both coordination tasks while the low frequency group was well able to use visual information for both. In the mixed training pairs, the low frequency trained member of the pair was likely responsible for the better performance. These conclusions were consistent with results of previous studies.     

The learning of 90° continuous relative phase with and without Lissajous feedback: external and internally generated bimanual coordination

Results from recent experiments (e.g., Kovacs, Buchanan, & Shea, 2009a–b, 2010a,b) suggest that when salient visual information is presented using Lissajous plots bimanual coordination patterns typically thought to be very difficult to perform without extensive practice can be performed with remarkably low relative phase error and variability with 5 min or less of practice. However, when this feedback is removed, performance deteriorates. The purpose of the present experiment was to determine if reducing the frequency of feedback presentation will decrease the participant's reliance on the feedback and will facilitate the development of an internal representation capable of sustaining performance when the Lissajous feedback is withdrawn. The results demonstrated that reduced frequency Lissajous feedback results in very effective bimanual coordination performance on tests with Lissajous feedback available and when feedback is withdrawn. Taken together the present experiments add to the growing literature that supports the notion that salient perceptual information can override some aspects of the system's intrinsic dynamics typically linked to motor output control. Additionally, the present results suggest that the learning of both externally and internally driven bimanual coordination is facilitated by providing reduced frequency Lissajous feedback.     

Temperature dependence of the low-cycle fatigue behaviour of a Cu-SiO2 bicrystal with a [011], 18° twist boundary

The temperature dependence of the low-cycle fatigue behaviour of a Cu bicrystal containing dispersed SiO₂ particles and having a [011], 18° twist boundary has been studied. Failure occurred at shorter times with increasing temperature and stress amplitude. Crack nucleation took place at the particles' surfaces on the grain boundary where slip lines intersected. The crack tended to propagate along primary slip lines and this tendency became stronger as the temperature was increased.     

Attitudes of learner drivers toward safety at level crossings: Do they change after a 360° video-based educational intervention?

In light of the growing number of level crossing accidents and the limited prevention programmes, this study examined relationships among attitudes toward traffic rules, impulsiveness, and behavioural intentions at level crossings. It explored the behavioural effects of an educational programme newly developed within the framework of the Croatian national safety project “Implementation of measures to improve the safety of the most vulnerable traffic participants at level crossings“. The programme aimed to change risky attitudes and behavioural intentions of learner drivers at level crossings. It consists of a safety lecture accompanied by pictures, videos and the exposition to a 3D virtual reality film shot at a real level crossing, which allows the participant to experience, from the driver’s perspective, safe and risky crossings. The programme was implemented in 11 driving schools. First, 285 participants (62.8% men) answered a questionnaire measuring safety attitudes toward traffic and impulsiveness, then they attended a lecture and participated in the virtual reality experience. Finally, they answered a questionnaire measuring planned future behaviour at level crossings. The results showed that attitudes toward level crossing risk significantly predicted intended driving behaviour at level crossings. Furthermore, the 360° video-based educational intervention altered the relationships connecting attitudes toward level crossings and risky driving behaviour at level crossings. The practical implications of these results are discussed.     

TEM observation of oxide scale formed on a Ti–Al–Zr alloy oxidized at 360°C in alkaline steam

Ti–Al–Zr alloy has been oxidized at 360°C in alkaline steam at a pressure of 10.3?±?0.7?MPa. Cross-sectional transmission electron microscopy (TEM) observations indicated that the oxide scale of Ti–Al–Zr alloy was composed of outer and inner subscales, in which the outer layer consists of anatase-TiO₂ and the inner layer a mixture of TiO and Ti₂O. The thickness of the Ti₂O, TiO and anatase-TiO₂ were approximately 50, 100 and 400?nm, respectively. These results were confirmed by X-ray energy dispersive spectrometry (EDS) measurements. The enhanced corrosion of titanium alloys in LiOH solution is attributed to a high hexagonal Ti₂O to tetragonal TiO₂ phase transformation rate induced by the substitution of Li⁺ for Ti⁴⁺ in the oxide layer.     

Perceptual-cognitive performance of youth soccer players in a 360°-environment – An investigation of the relationship with soccer-specific performance and the effects of systematic training

IntroductionSoccer is a complex game in which athletes perform in a dynamic 360°-environment. The results of numerous studies highlight the importance of perceptual-cognitive functions for soccer performance. Moreover, in recent years, the idea of improving sports performance through systematic perceptual-cognitive training has been increasingly investigated. Contradictory results and limitations in previous research call for further investigation. The current study aims to investigate both the relationship between perceptual-cognitive performance in a dynamic 360°-environment and soccer performance as well as the effects of perceptual-cognitive training in such an environment on soccer performance.Methods42 youth soccer players aged 11–13 years were tested at a first time of measurement (T1) on their perceptual-cognitive functions using a 360°-multiple object tracking task (360-MOT) and a visuospatial attention task. Soccer performance was assessed using an isolated, validated 360°-passing task and a small-sided game. Subsequently, participants were randomly divided into a perceptual-cognitive training group, an active control group, or a passive control group. Participants in the training group received 360-MOT training twice per week during a 5-week intervention phase, while participants in the active control group received a pseudo video training. Perceptual-cognitive and soccer-specific performance was assessed after the intervention phase at a second time of measurement (T2).ResultsAt T1, there was a significant positive relationship between 360-MOT performance and both the accuracy score in the 360°-passing task and the defensive performance score in the small-sided game. Regarding the perceptual-cognitive training intervention, the analysis at T2 revealed significant task-specific training effects but no transfer effects on perceptual-cognitive or soccer-specific performance.ConclusionsThe results highlight the relevance of perceptual-cognitive performance in a 360°-environment for soccer-specific performance but question the effects of short isolated perceptual-cognitive training interventions on soccer-specific performance.