Atomic geometry and energetics of carbon nanotube necking

Molecular mechanics simulations were performed to probe the incipient plastic deformation in carbon nanotubes (CNTs), which involves nucleation of Stone–Wales (SW) defects and spiral glide of 5/7 dislocation dipoles that lead to quantized necking through a stepwise reduction in tube diameter. Quantification of the strain-dependent energetics of dislocation glide reveals that such dislocation motions are energetically favoured at high tensile strain. Pre-existing dislocations critically affect subsequent nucleation and separation of SW defects, as manifested by the competing deformation modes of symmetric versus asymmetric necking. The results provide a quantitative basis for the dislocation dynamics simulations of superplastically deformed CNTs.     

台湾地区“代孕”立法最新进展及其启示

2007年3月21日,台湾地区在广泛调研、民主决策的基础上,终于颁布实施了《人工生殖法》,使争论已久的代孕人工生殖问题与《人工生殖法》正式脱钩,另行规制;此前,《代孕人工生殖法》草案也已经出笼,拟有条件开放代孕人工生殖。相关草案对代孕者、受术夫妻、代孕中介、代孕契约、亲子关系等问题都进行了具体规定。台湾地区的立法经验对祖国大陆完善包括代孕在内的人工生殖法具有一定的借鉴意义。     

How do shy people expand their social networks? Using social surrogates as a strategy to expand one's network

The authors examined the use of social surrogates by shy people to expand their social network when entering a new environment, following Bradshaw's social surrogate hypothesis. The authors conducted a panel survey of 70 friendship pairs of students 7 months after they entered university. The results revealed that when a friend acted as a surrogate, the shy students extended their joint networks more. In contrast, not-shy students extended their networks regardless of whether a friend acted as a surrogate. These results indicate that even shy people can adjust indirectly to new social circumstances because they can expand their social networks by using a close friend as a surrogate.     

Meta‐CART: A tool to identify interactions between moderators in meta‐analysis

In the framework of meta‐analysis, moderator analysis is usually performed only univariately. When several study characteristics are available that may account for treatment effect, standard meta‐regression has difficulties in identifying interactions between them. To overcome this problem, meta‐CART has been proposed: an approach that applies classification and regression trees (CART) to identify interactions, and then subgroup meta‐analysis to test the significance of moderator effects. The previous version of meta‐CART has its shortcomings: when applying CART, the sample sizes of studies are not taken into account, and the effect sizes are dichotomized around the median value. Therefore, this article proposes new meta‐CART extensions, weighting study effect sizes by their accuracy, and using a regression tree to avoid dichotomization. In addition, new pruning rules are proposed. The performance of all versions of meta‐CART was evaluated via a Monte Carlo simulation study. The simulation results revealed that meta‐regression trees with random‐effects weights and a 0.5‐standard‐error pruning rule perform best. The required sample size for meta‐CART to achieve satisfactory performance depends on the number of study characteristics, the magnitude of the interactions, and the residual heterogeneity.     

The <Emphasis Type="Italic">Not Unreasonable</Emphasis> Standard for Assessment of Surrogates and Surrogate Decisions

Standard views on surrogate decision making present alternative ideal models of what ideal surrogates should consider in rendering a decision. They do not, however, explain the physician's responsibility to a patient who lacks decisional capacity or how a physician should regard surrogates and surrogate decisions. The authors argue that it is critical to recognize the moral difference between a patient's decisions and a surrogate's and the professional responsibilities implied by that distinction. In every case involving a patient who lacks decisional capacity, physicians and the treatment team have to make judgments about the appropriateness of both the surrogate and the surrogate's decision. They have to assess the surrogate's decisional capacity and attitude toward the patient as well as the reasons that support the surrogate's decision. This paper provides a model for acceptable surrogate decisions and a standard for blocking inappropriate surrogates. Only decisions based on widely shared reasons are allowable for surrogate refusal of highly beneficial treatment.     

Reformation Humanism: Reading the Classics in the New Theology

Scholarly discussions on what constitutes Christian humanism in the Renaissance and Reformation periods have typically concentrated on its manifestations before 1536, when Erasmus died. In this period, the old arguments for the reading of the Classics once set out by Basil and Augustine still predominated. Calvin’s teaching on the Fall and the noetic effects of sin, however, provided another basis for the incorporation of pagan thought into Christian learning. Christians who followed Calvin benefited from his precise and comprehensive theological position on the place of worldly knowledge in God’s original creation as a means for justifying their study of the Classics.     

用于处理不努力作答的标准化残差系列方法和混合多层模型法的比较

文章采用模拟研究, 分别在混合多层模型假设满足和违背的情境下, 比较了混合多层模型方法与标准化残差系列方法在识别不努力作答和参数估计方面的表现。结果显示：(1)不存在不努力作答或其严重性低时, 各方法表现接近; (2)不努力作答严重性高时, 固定参数迭代标准化残差法普遍更优, 混合多层模型法仅在假设满足且两种作答反应时差异大的条件下表现较好。建议实际应用中优先选择固定参数迭代标准化残差法。     

Testing the Physical Activity Self-Definition Model among low-active adults participating in a physical activity intervention

Seeing oneself as a physically active person is one of the strongest predictors of physical activity behaviour and self-regulatory strategies. Determining whether and how physical activity self-perceptions can be stimulated may help low-active individuals who do not see themselves as a physically active person become more active. Cross-sectional research has tested the Physical Activity Self-Definition (PASD) model among active samples; longitudinal studies among low-active adults have yet to be done. The purpose of this study was to test the predictive power of the PASD model among low-active adults over a 16-week physical activity intervention. Participants completed surveys of validated questionnaires in-person at baseline (pre-intervention) and at 16-weeks (end of intervention) at one of two primary care facilities. The final sample included 119 low-active adults. Partial least squares-structural equation modeling indicated that the original model had small-medium predictive power (Q² = 0.22; SRMR = 0.13 [0.05, 0.07]; RMSE = 1.13; MAE = 0.9; BIC = 1348.40). Two paths were added in the revised model (perceived wanting—PASD; perceived ability—perceived commitment), which explained an additional 4% and 5% of the variance in perceived commitment (R² = 0.62 [0.48, 0.72]) and PASD (R² = 0.74 [0.64, 0.80]; all p’s < 0.001), respectively. The revised model had medium predictive power (Q² = 0.25; SRMR = 0.11 [0.05, 0.06]; RMSE = 1.1; MAE = 0.87; BIC = 1332.84) All path coefficients remained positive and significant at p ≤ .001. Among low-active adults, perceived wanting and perceived ability may be more salient when engaging in physical activity and regarding themselves as a physically active person. Findings may support practitioners and health care professionals in designing physical activity interventions to foster PASD among low-active adult populations.