Temporal modulations of agonist and antagonist muscle activities accompanying improved performance of ballistic movements

Although many studies have examined performance improvements of ballistic movement through practice, it is still unclear how performance advances while maintaining maximum velocity, and how the accompanying triphasic electromyographic (EMG) activity is modified. The present study focused on the changes in triphasic EMG activity, i.e., the first agonist burst (AG1), the second agonist burst (AG2), and the antagonist burst (ANT), that accompanied decreases in movement time and error. Twelve healthy volunteers performed 100 ballistic wrist flexion movements in ten 10-trial sessions under the instruction to "maintain maximum velocity throughout the experiment and to stop the limb at the target as fast and accurately as possible". Kinematic parameters (position and velocity) and triphasic EMG activities from the agonist (flexor carpi radialis) and antagonist (extensor carpi radialis) muscles were recorded. Comparison of the results obtained from the first and the last 10 trials, revealed that movement time, movement error, and variability of amplitudes reduced with practice, and that maximum velocity and time to maximum velocity remained constant. EMG activities showed that AG1 and AG2 durations were reduced, whereas ANT duration did not change. Additionally, ANT and AG2 latencies were reduced. Integrated EMG of AG1 was significantly reduced as well. Analysis of the alpha angle (an index of the rate of recruitment of the motoneurons) showed that there was no change in either AG1 or AG2. Correlation analysis of alpha angles between these two bursts further revealed that the close relationship of AG1 and AG2 was kept constant through practice. These findings led to the conclusion that performance improvement in ballistic movement is mainly due to the temporal modulations of agonist and antagonist muscle activities when maximum velocity is kept constant. Presumably, a specific strategy is consistently applied during practice.     

媒体信任与现代公民文化的成长——影响公民文化成长与培育的媒体信任因素探析

本文以南京市的实证调查为研究个案,通过公民对媒体的信任程度与公民文化之间的方差分析与多元回归分析,描述公民对媒体的信任程度与公民文化成长的关联.媒体是现代社会传播政治知识、培育现代公民文化的重要社会力量,提升公民对媒体的信任度是促进公民文化培育的可行途径之一.     

Mentoring relationships from early adolescence through emerging adulthood: A qualitative analysis

This study compared perceptions of mentoring relationships among early adolescents, middle adolescents, and emerging adults. In ten focus groups, 56 middle school, high school, and college students described relational experiences that were analyzed thematically. Differences in the characteristics of the mentors nominated by the youth across the age groups were noted and five broad themes identified. Three themes were similar across the different age groups: (a) the importance of spending time together and engaging in shared activities, (b) trust and fidelity, and (c) role modeling and identification. Two themes were present in the narratives of all three age groups but played out differently in ways that were consistent with developmental issues and needs of that age group: (a) balancing connection and autonomy and (b) empowerment. These data can help guide future research and practice involving youth mentoring relationships across developmental and disciplinary divides.     

Sex-specific clinical correlates of hoarding in obsessive-compulsive disorder

Little is known about whether the clinical correlates of hoarding behavior are different in men and women with obsessive-compulsive disorder (OCD). In the current study, we evaluated the association of hoarding with categories of obsessions and compulsions, psychiatric disorders, personality dimensions, and other clinical characteristics separately in 151 men and 358 women with OCD who were examined during the OCD Collaborative Genetics Study. We found that, among men but not women, hoarding was associated with aggressive, sexual, and religious obsessions and checking compulsions. In men, hoarding was associated with generalized anxiety disorder and tics whereas, among women, hoarding was associated with social phobia, post-traumatic stress disorder, body dysmorphic disorder, nail biting, and skin picking. In women but not men, hoarding was associated with schizotypal and dependent personality disorder dimensions, and with low conscientiousness. These findings indicate that specific clinical correlates of hoarding in OCD are different in men and women and may reflect sex-specific differences in the course, expression, and/or etiology of hoarding behavior in OCD.     

Prevalence and correlates of hoarding behavior in a community-based sample

Little is known about the prevalence and correlates of hoarding behavior in the community. We estimated the prevalence and evaluated correlates of hoarding in 742 participants in the Hopkins Epidemiology of Personality Disorder Study. The prevalence of hoarding was nearly 4% (5.3%, weighted) and was greater in older than younger age groups, greater in men than women, and inversely related to household income. Hoarding was associated with alcohol dependence; paranoid, schizotypal, avoidant, and obsessive-compulsive personality disorder traits; insecurity from home break-ins and excessive physical discipline before 16 years of age; and parental psychopathology. These findings suggest that hoarding may be relatively prevalent and that alcohol dependence, personality disorder traits, and specific childhood adversities are associated with hoarding in the community.     

数学性别刻板印象的内隐联想测验研究

本研究采用IAT实验设计,考察大学生的内隐数学-性别刻板印象.结果发现,IAT方法能检测到大学生存在"男性比女性更擅长数学"的内隐数学-性别刻板印象;IAT所测量到的内隐数学-性别刻板印象有性别差异,所测得的内隐数学-性别刻板印象没有专业差异; IAT与SEB所测得的结果不相同,IAT和SEB测得的是被试记忆中复杂网络联结的不同方面.     

大学生网络社会支持测评初探

参照已有的文献并结合广泛的调查研究,编制了我国大学生网络社会支持量表,探讨大学生网络交往中所获得的社会支持类型.探索性因素分析结果表明,大学生网络社会支持主要包括情感支持、工具性支持、信息支持、社会成员支持四个维度,4因素结构的结果在验证性因素分析中得到了验证.该量表的信度、效度符合心理测量学的要求.     

创业失败与再创业意向的作用机制

近年来, 我国政府对创业支持力度不断加强, 创业活动日益活跃, 但失败率却居高不下。如何让创业者在遭遇失败后仍能保持再创业的意向是当前亟待解决的现实问题。拟综合采取横向问卷调查、纵向时间对比以及情景模拟实验的方法, 一方面探讨成就目标导向和社会比较在创业失败和创业失败学习之间的有中介的调节作用; 另一方面分析创业失败学习、创业自我效能感在创业失败和再创业意向之间的链式多重中介作用机制, 寻求由创业失败到再创业意向的不同路径, 这种探讨具有理论创新价值。依据实证研究的结论在实践中指导创业者通过上行比较, 锁定学习目标, 激发再创业意向; 通过提高自我怜悯水平, 使创业者摆脱消极情绪的困扰, 激发掌握性学习动机, 确立再创业的意向, 对于创业者具有重要指导意义。社会比较和自我怜悯的干预研究具有鲜明的中国文化特色。     

Counselor Ethnicity,Counselor Nonverbal Behavior,and Session Outcome With Asian American Clients: Initial Findings

Five Asian American and 5 European American female counselors each saw 3 Asian American volunteer clients for 1 session of career‐focused individual counseling. Examination of counselor nonverbal behaviors revealed that European American counselors displayed significantly greater frequency of adaptors, postural shifts, and smiles than did Asian American counselors. The frequency of smiles was significantly positively correlated with client‐rated session positivity and session arousal, and the frequency of postural shifts was significantly positively correlated with client‐rated session arousal. Limitations and implications of the findings are described.     

发展生产性服务业促进长三角经济发展

境外经济发达国家和地区的服务业为吸纳劳动力的主要行业,而长三角却长期以制造业为吸纳长三角地区劳动力就业的主要产业.最近,服务业吸纳劳动力的绝对数值不断增加,有学者认为长三角地区的服务业正在取代制造业成为吸纳劳动力的主要行业.本文分析指出:在长三角,制造业仍在就业比重中占主导地位;服务业已经连续7年占GDP的比重几乎不变,这是服务业发展停滞、遇到障碍的信号.本文认为这是由于生产性服务业发展不足而造成的结构性问题;发展生产性服务业是促进服务业发展、提高服务业就业率之良策,从而,此举还有扩大长三角内需之经济效果.