动机过程对青少年网络游戏行为意向的影响模型

从行为动机的角度探讨影响青少年网络游戏玩家游戏意向的主要因素。通过对北京市中学生进行抽样调查并采用结构方程模型的方法对模型进行检验。结果显示,青少年网络游戏玩家的游戏意向受多种内在动机和外在动机共同影响。青少年玩网络游戏的基本内在动机（如,社会交际、超越现实、自我效能和享受乐趣）促进沉浸动机的形成。同时,沉浸是提高游戏意向的内在动机,主观规范和游戏涉入度是分别降低和提高游戏意向的外在动机。此外,内部动机和外部动机对游戏意向的影响存在交互作用     

The global non-entropic arrow of time: from global geometrical asymmetry to local energy flow

Since the nineteenth century, the problem of the arrow of time has been traditionally analyzed in terms of entropy by relating the direction past-to-future to the gradient of the entropy function of the universe. In this paper, we reject this traditional perspective and argue for a global and non-entropic approach to the problem, according to which the arrow of time can be defined in terms of the geometrical properties of spacetime. In particular, we show how the global non-entropic arrow can be transferred to the local level, where it takes the form of a non-spacelike local energy flow that provides the criterion for breaking the symmetry resulting from time-reversal invariant local laws.     

When Effort Is Enjoyed: Two Studies of Intrinsic Motivation for Personally Salient Activities

Distinctions between two philosophical conceptions of happiness, hedonism and eudaimonism, were applied to the study of intrinsic motivation. Modified versions of the Personally Expressive Activities Questionnaire (PEAQ) were used in two studies to contrast activities, all of which were enjoyed, but which differed in the level of effort involved. In Study 1, 173 college students were free to choose any type of activity that met the selection criteria. In Study 2, the activities chosen by 95 undergraduates were limited to activities associated with a particular leisure time or hobby activity in which the respondents engaged on a regular basis. Consistent results across the two studies indicate that High Effort–Liked activities, in comparison to Low Effort–Liked activities, were associated with greater interest, flow, and feelings of personal expressiveness, greater perceived competence, and higher scores for both self-realization values and importance. These differences are discussed for their implications for the conceptual understanding of intrinsic motivation.     

Guiding drivers towards safer driving speed: Exploiting visual dominance in speed adaptation

Inappropriate speed is a main cause of accidents. Drivers are often unaware of potential risks due to inadequate speed. To prevent dangerous situations, we need to understand perceptual factors influencing human speed perception. Due to the prominent role of vision in driving, we examined the effect of visuo-spatial stimuli on speed based on the optic flow. While developing an adaptive infrastructure measure to reduce speed, we conducted two consecutive studies, a driving simulator study and a field test to investigate findings further. In both studies, we placed lights on two sides of a highway exit and either illuminated them statically or activated them in a way that they appeared to be moving towards the driver. We expected drivers to slow down more when seeing static light stimuli compared to a baseline without lights. We also expected drivers to decrease speed more in conditions with oncoming lights compared to a baseline, and to static lights, due to distorted speed perception. The first study in a static driving simulator revealed no difference between conditions. In the field test, both static lights and lights moving towards the driver led to a speed reduction compared to a baseline but did not differ from one another. Lights in general led to lower driving speed, potentially due to their warning character, but we found no difference between the light conditions, suggesting that the effect might not be based on the optic flow. Future research should investigate the relationship between driven and perceived speed more closely.     

To pass or not to pass: More a question of body orientation than visual cues

This study investigated the influence of pitch body tilt on judging the possibility of passing under high obstacles in the presence of an illusory horizontal self-motion. Seated subjects tilted at various body orientations were asked to estimate the possibility of passing under a projected bar (i.e., a parking barrier), while imagining a forward whole-body displacement normal to gravity. This task was performed under two visual conditions, providing either no visual surroundings or a translational horizontal optic flow that stopped just before the barrier appeared. The results showed a main overestimation of the possibility of passing under the bar in both cases and most importantly revealed a strong influence of body orientation despite the visual specification of horizontal self-motion by optic flow (i.e., both visual conditions yielded a comparable body tilt effect). Specifically, the subjective passability was proportionally deviated towards the body tilt by 46% of its magnitude when facing a horizontal optic flow and 43% without visual surroundings. This suggests that the egocentric attraction exerted by body tilt when referring the subjective passability to horizontal self-motion still persists even when anchoring horizontally related visual cues are displayed. These findings are discussed in terms of interaction between spatial references. The link between the reliability of available sensory inputs and the weight attributed to each reference is also addressed.     

Mobility of c dislocations in Ti3, Al

Abstract

The rôle of dislocations with Burgers vectors, b, given by b = [0001] during deformation of samples of the intermetallic compound Ti₃Al has been assessed. At room temperature, the experimental evidence is consistent with these dislocations being sessile, their density and morphology being similar to that in undeformed samples. In samples deformed at 650°C and above, it is concluded that motion of these dislocations is effected by dislocation climb. The line directions of the various segments of dislocations with b= [0001] are shown to be perpendicular to planes that contain sheets of Ti atoms, with an expected tendency to exhibit a high Peierls stress.     

The Dopamine D4 Receptor (DRD4) Exon 3 VNTR Contributes to Adaptive Personality Differences in an Italian Small Island Population

The search for evolutionary forces shaping the diversity of human personality traits encouraged studies that have found that islanders are relatively closed and introverted, with little interest in the external world. The ‘personality gene flow’ hypothesis was proposed to explain the mechanism underlying this difference, suggesting that the frequency of alleles that influence islander personality traits might progressively increase in the gene pools on islands because of selective emigration of individuals not displaying these alleles. We genotyped 96 individuals from the Italian mainland and 117 from Giglio Island, whose residents were previously assessed regarding their personality traits. We genotyped three polymorphisms: the dopamine D4 receptor (DRD4) exon 3 repeat region, the serotonin‐transporter SLC6A4 5‐HTTLPR indel and the dopamine transporter SLC6A3 DAT1 3′UTR repeat region. Only the DRD4 exon 3 repeat was hypothesised to show varying allele frequencies because this polymorphism could be associated with human migration and personality traits such as extraversion, openness and novelty seeking. As predicted, no differences in allele frequencies were found for the SLC6A4 and SLC6A3 polymorphisms, whereas significant differences were observed in the frequency of the DRD4 exon 3 alleles. The DRD4.2 repeat was more common in mainlanders, as expected, whereas the DRD4.7 allele was over‐represented among islanders who never emigrated. This last result contradicts the suggested association of this allele with long‐distance migrations. We suggest that emigration might have caused gene flow out the island that resulted in somewhat unpredictable changes in the frequencies of specific alleles, thus influencing islander personality traits. Copyright © 2013 European Association of Personality Psychology     

A model for 〈c+a〉 dislocation transmission across nano-spaced parallel basal stacking faults in a HCP alloy

We develop a model for recently observed 〈c + a〉 dislocation transmission across nano-spaced parallel basal stacking faults in hexagonal close-packed (HCP) Mg microcrystalline grains. The model theoretically predicts nanospace-dependent yield strength that is in good agreement with experimental data. Additionally, it theoretically predicts activation volume and strain rate sensitivity.     

Left orbital frontal activation in pathological anxiety

Twelve patients with anxiety disorder were studied with respect to regional cerebral blood flow (rCBF) using a 32-detector system with the 133 Xe inhalation technique. Measurements were taken during a rest condition and during anxiety induction. Anxiety relevant to the patient's psychological disorder was induced with a projective test, the meta-contrast technique (MCT). Increased blood flow in the orbital frontal region of the left hemisphere was observed in each of the 11 subjects who showed evidence of experiencing anxiety during the procedure. In a second study four additional anxiety patients were studied with a high-resolution (254-detector)Xe rCBF system. In addition to the anxiety and resting conditions, a neutral verbalization condition was added to control for the verbal aspects of the anxiety induction procedure. The results again showed the experience of anxiety to be accompanied by increased blood flow in the left orbital frontal region, with the patients showing this flow increase to be greater in the posterior, paralimbic, areas of the region. These results are consistent with previous suggestions of left hemisphere involvement in anxiety. They also suggest that imaging methods may allow research into what appears to be exaggerated corticolimbic activity in this disorder.     

自身运动认知的神经机制

通过光流信息来指导个体在环境中有效移动是我们视觉神经系统的一项核心任务。在灵长类的大脑皮层, 视觉运动的信息加工是由位于背侧通路的一系列脑区来完成的, 这一信息通路主要参与运动和空间动作的分析。在高级视皮层, 视觉系统很可能利用非视觉信息来补偿因眼动造成的光流模式扭曲, 以重建对自身运动方向的正确表征。根据目前研究进展, MST和VIP这两个位于顶叶的脑区都参与了自身运动认知过程, 并且对精确的自身运动方向判断是不可或缺的。本文系统介绍了近些年来在自身运动认知神经机制研究领域的进展, 尤其是神经生理学家们利用非人灵长类动物模型在自身运动认知皮层处理机制方面的成果。同时也提出了一些深入研究急需解决的关键问题。