Role of Zr on growth kinetics and microstructural evolution of the superconductor V3Ga by the bronze technique

The influence of Zr on the growth of V₃Ga is studied by a diffusion-couple technique mimicking the bronze method for superconductor production. Systematic quantitative evaluation on critical-current-density-dependent metallurgical parameters is addressed. A mixture of V₃Ga and Zr-containing phases develops at the interdiffusion zone. Smaller grains on Zr addition cause higher growth kinetics owing to grain-boundary diffusion of Ga. The grains are oriented randomly irrespective of Zr addition. Refined microstructure, second-phase, and higher growth kinetics suggest a beneficial role of Zr for the better functioning of the superconductor.     

Inter-individual neural differences in movement imagery abilities

ObjectivesBuilding on mounting evidence distinguishing the neurological basis of different movement imagery abilities (visual versus kinesthetic), this study compared brain activity (i.e., blood flow changes) through functional magnetic resonance imaging elicited by movement imagery in participants self-reporting good and poor imagery abilities with the Movement Imagery Questionnaire-3. Participants also completed the Vividness of Movement Imagery Questionnaire-2. Method: Thirty-seven females (good imagery ability = 18; poor imagery ability = 19) were randomly presented with four experimental conditions (i.e., Kinesthetic, Internal Perspective, External Perspective and Rest) counterbalanced for condition, during three separate 11-min functional brain scans. Results: Kinesthetic and visual (internal/external) subscale mean differences of the Vividness of Movement Imagery Questionnaire-2 favored good imagers and high Movement Imagery Questionnaire-3 inter-scale correlations evidenced convergent validity. As in prior published work, kinesthetic, internal, and external visual imagery elicited distinct patterns of brain activation relative to rest. Overall, the patterns of brain activity in the good and poor imager groups were remarkably similar, indicating that they both generally relied on a similar brain network during movement imagery. Conclusions: Contrary to processing efficiency hypotheses (i.e., neural efficiency hypothesis) we report that during kinesthetic imagery and external visual imagery only, good imagers actually activated a greater number of spatially distinct cortical sites than did poor imagers. Furthermore, research is needed to fully characterize the neural signature of movement imagery in good and poor imagers. Such research is critical to the appropriate creation and proper application of neuroscience-inspired movement imagery-based learning interventions in healthy and clinical populations.     

Influence of dorsal hippocampal lesions and MMP inhibitors on spontaneous recovery following a habituation/classical conditioning head–shake task

The present investigation combined a classical conditioning paradigm with a head–shake response (HSR) habituation task in order to evaluate the importance of dorsal hippocampal neural plasticity to spontaneous recovery. In the first experiment animals exhibited rapid HSR habituation (air stimulus to the ear) and an 85% level of spontaneous recovery following a 24 h inter-session interval. The addition of a brief tone prior to the air stimulus produced a similar pattern of habituation during the first session, but the level of spontaneous recovery was reduced (44%) during Session II. In a second experiment dorsal hippocampal lesioned rats placed on this tone/HSR paradigm responded with an 87% level of spontaneous recovery during Session II; while neocortex lesioned control rats indicated significantly reduced levels of spontaneous recovery (55%). In a third experiment bilateral injections of a general MMP inhibitor, FN-439, into the dorsal hippocampus resulted in high levels of spontaneous recovery (81%); while control rats injected with artificial cerebrospinal fluid displayed a significant attenuation of spontaneous recovery (45%). Finally, animals bilaterally injected with a specific MMP-3 inhibitor into the dorsal hippocampus indicated very similar results to those obtained following FN-439 injection. These findings indicate that animals prepared with dorsal hippocampal lesions, or injections with an MMP inhibitor, revealed an impaired association between the tone and air stimulus thus maximum spontaneous recovery was present 24 h later. Thus, it appears that the dorsal hippocampus influences habituation by conserving responses and reducing spontaneous recovery when a temporally contingent signaling cue is present.     

情绪干扰听觉反应冲突的ERP研究

采用ERP技术研究13例正常青年人在声音诱发的不同情绪条件下,对反应抑制加工过程的影响,并试图阐明其潜在脑机制。实验中选择正、中、负三种声音各50种,作为诱发情绪的刺激材料。结果发现Go条件下的反应时在负性、中性、正性条件下依次减短;Go与Nogo刺激均诱发出显著的N1成分,中性条件下波幅显著大于正负性情绪条件。此外,三种情绪背景下, Nogo刺激诱发出显著的N2与P3成分。Nogo-N2主要分布在头皮前中部,在Fz点波幅最大。Nogo-P3主要分布在头皮中部,Pz点波幅最大。中性条件下Nogo-N2波幅显著大于负性与正性条件,而正性和负性之间差异不显著。行为结果表明,听觉负性情绪诱发对反应执行有干扰作用;ERP结果表明声音诱发的情绪对早期听觉选择性注意具有调节作用。听觉情绪诱发对反应抑制加工过程有显著影响,且该影响在早期反应冲突监控阶段最为明显。     

Do the right thing: but only if others do so

Social norms play an important role in individual decision making. We argue that two different expectations influence our choice to obey a norm: what we expect others to do (empirical expectations) and what we believe others think we ought to do (normative expectations). Little is known about the relative importance of these two types of expectation in individuals' decisions, an issue that is particularly important when normative and empirical expectations are in conflict (e.g., systemic corruption, high crime cities). In this paper, we report data from Dictator game experiments where we exogenously manipulate dictators' expectations in the direction of either selfishness or fairness. When normative and empirical expectations are in conflict, we find that empirical expectations about other dictators' choices significantly predict a dictator's own choice. However, dictators' expectations regarding what other dictators think ought to be done do not have a significant impact on their decisions after controlling for empirical expectations. Our findings about the crucial influence of empirical expectations are important for designing institutions or policies aimed at discouraging undesirable behavior. Copyright © 2008 John Wiley & Sons, Ltd.     

The influence of perceptual and semantic categorization on inhibitory processing as measured by the N2–P3 response

In daily activities, humans must attend and respond to a range of important items and inhibit and not respond to unimportant distractions. Our current understanding of these processes is largely based on perceptually simple stimuli. This study investigates the interaction of conceptual-semantic categorization and inhibitory processing using Event Related Potentials (ERPs). Participants completed three Go–NoGo tasks that increased systematically in the degree of conceptual-semantic information necessary to respond correctly (from single items to categories of objects and animals). Findings indicate that the N2 response reflects inhibitory processing but does not change significantly with task difficulty. The P3 NoGo amplitude, on the other hand, is attenuated by task difficulty. Further, the latency of the peak of the P3 NoGo response elicited by the most difficult task is significantly later than are the peaks detected during performance of the other two tasks. Thus, the level of complexity of conceptual-semantic representations influences inhibitory processing in a systematic way. This inhibition paradigm may be a key for investigating inhibitory dysfunction in patient populations.     

Infant Mental Health assessment: the use of DC 0-3 in an outpatient child psychiatric clinic in Scandinavia

The study focuses on Infant Mental Health data from an outpatient psychiatric clinic using the "Diagnostic Classification of Mental Health and Developmental Disorders of Infancy and Early Childhood" (DC 0-3) and parental questionnaires, CBCL and ITSC. In total, 138 infants (aged 0-3) went through the diagnostic procedure. Sixty-eight per cent were diagnosed within Axis I, with regulatory disorder, disorder of affect and traumatic stress disorder being the most frequent diagnoses. In addition, 48% were classified as having a relationship disorder according to Axis II, with an additional 40% being considered to be at risk of developing a relationship disorder. The mothers' and fathers' ratings of their children's externalized and sensitivity problems were in agreement with the clinicians, but the ratings of internalized problems as well as relationship problems presented a more complex pattern.     

Gaze following among toddlers

Children's cooperative activities with their peers become markedly coordinated during the 3rd year of life. During these activities, the child needs to follow his/her peers’ gaze to objects, and look at the same objects to initiate coordinated action. Since 3-year-olds’ ability to follow their peers’ gaze has not been studied, we experimentally investigated this in our study. In the experimental trials, an experimenter induced a child (looker) to look at a doll on display, and observed the reaction of another child (follower) who was in front of the looker (and not looking at the doll). In the control trials, the experimenter displayed the doll in an identical manner when the follower was alone. The followers followed the gaze of the lookers, looking at the doll in approximately 90% of the experimental trials, compared with 20% of the control trials. These results indicate that 3-year-olds can follow their peers’ gaze.     

三苏论管仲的异同及形成原因

学术界对管仲的研究越来越深入细致,对三苏的研究更是全面精微,遗憾的是几乎没有人研究管仲和三苏之间的联系,事实上三苏对管仲都非常关注,甚至各自都有同题文章《管仲论》,本文正是拟从前人的这些缺憾入手,深入系统地分析研究三苏对管仲的评价与论述,从而深层次地分析管仲的历史影响以及三苏对同一历史人物的相同与不同的看法,更全面地了解三苏其人其事和管仲其人其书。