Crystallization and thermal stability of polypropylene/multi-wall carbon nanotube nanocomposites

Polypropylene (PP)/multi-wall carbon nanotube (MWCNT) nanocomposites were prepared via a melt compounding method using a twin-screw extruder. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to study the crystallization and thermal stability of the nanocomposites. The DSC analysis results revealed that the existence of MWCNTs in a PP matrix, which acted as a nucleating agent enhancing the crystallization process of PP matrix. This behaviour was manifested by an increase in the crystallization temperature and crystallinity index of the nanocomposites. Additionally, the TGA results showed that the addition of MWCNTs dramatically increased the thermal stability of the PP/MWCNT nanocomposites. Generally, MWCNT type C-70P showed improved crystallization and better thermal stability of the nanocomposites compared to type C-150P.     

Effect of pressure on the mechanical and dynamical stability of NaAlSi

The effects of pressure on the mechanical and dynamical stability of NaAlSi have been fully investigated by first-principles calculations within the generalised gradient approximation (GGA). The obtained results show that the optimised lattice constants, atomic positions and elastic constants at ambient pressure are in good agreement with the available experimental and theoretical data. The lattice constants decrease monotonically with increasing pressure. The elastic constant C₁₁, C₁₂, C₁₃, C₃₃ and C₆₆ increase while C₄₄ decreases with increasing pressure. It is found that NaAlSi is mechanically unstable when the pressure is above 25.97?GPa. The phonon-dispersion curves along several high symmetry lines are obtained. The phonon frequencies at the Z point decrease with increasing pressure and completely soften to zero at 27.52?GPa, further confirming the structural instability of NaAlSi.     

Long-term stability of the French WISC-IV: Standard and CHC index scores

Introduction

The assumption of the stability of intelligence is the source of the predictive value of the Intelligence Quotient (e.g., Full Scale IQ). However, few studies have investigated the long-term stability of one of the most frequently used tests in the field of cognitive assessment: the Wechsler Intelligence Scale for Children – 4th edition (WISC-IV).

Distance stability analysis in multidimensional scaling using the jackknife method

Stability or sensitivity analysis is an important topic in data analysis that has received little attention in the application of multidimensional scaling (MDS), for which the only available approaches are given in terms of a coordinate‐based analytical jackknife methodology. Although in MDS the prime interest is in assessing the stability of the points in the configuration, this methodology may be influenced by imprecisions resulting from the inherently necessary Procrustes method. This paper proposes an analytical distance‐based jackknife procedure to study stability and cross‐validation in MDS in terms of the jackknife distances, which is not influenced by the Procrustes method. For each object, the corresponding jackknife estimated points are considered as naturally clustered points, and stability and cross‐validation are analysed in terms of the MDS distances arising from the jackknife procedure, on the basis of a weighted cluster‐MDS algorithm. A jackknife‐relevant configuration is also proposed for cross‐validation in terms of coordinates, in a cluster‐MDS framework.     

轻微及中度抑郁者的积极自我

研究基于积极心理视角,考察抑郁个体在多个自我维度上,外显及内隐自尊的水平高低与稳定特性。被试选自高中学生,有效数据131人,分为抑郁(65人)与正常(66人)两组。所有被试在有/无应激两个时间点完成自我描述问卷II与改进内隐联想测验。结果发现,不论外显/内隐水平,抑郁个体倾向在指向个体内部的自我维度上具有积极自我,并且倾向在核心价值之外的自我维度上具有稳定自尊。由此证实,抑郁个体自我机制中的确存在积极成分。     

3～9岁儿童人格特质稳定性理解的发展特点

采用情境故事法对281名3～9岁儿童对不同类型的消极或积极特质稳定性的理解进行了个别测查,使用了“性质-类型-性质”的特质推理研究范式,任务涉及跨时间稳定性和跨情境一致性两个层面的考察。五因素重复测量方差分析结果表明,3～9岁儿童对于特质稳定性的理解表现出随年龄发展稳定观不断增强的趋势,4岁可能是儿童特质稳定性理解由不成熟向成熟方向发展的关键点;此外,研究验证了年龄与特质性质的交互作用,也发现了问题类型和特质类型对特质稳定性理解的调节作用。这些特点与年幼儿童获得的心理知识和对特质发展影响因素的觉知有关,也可能与整个文化系统的直接或间接作用有关。     

OUR COMMON ENEMY: COMBATTING THE WORLD'S DEADLIEST VIRUSES TO ENSURE EQUITY HEALTH CARE IN DEVELOPING NATIONS

In a previous issue of Zygon (Carvalho 2007), I explored the role of scientists—especially those engaging the science-religion dialogue—within the arena of global equity health, world poverty, and human rights. I contended that experimental biologists, who might have reduced agency because of their professional workload or lack of individual resources, can still unite into collective forces with other scientists as well as human rights organizations, medical doctors, and political and civic leaders to foster progressive change in our world. In this article, I present some recent findings from research on three emerging viruses—HIV, dengue, and rotavirus—to explore the factors that lead to the geographical expansion of these viruses and the increase in frequency of the infectious diseases they cause. I show how these viruses are generating problems for geopolitical stability, human rights, and equity health care for developing nations that are already experiencing a growing poverty crisis. I suggest some avenues of future research for the scientific community for the movement toward resolution of these problems and indicate where the science-religion field can be of additional aid.     

Stability and Change in Personality Disorder

ABSTRACT— The standard view of personality disorder is that it is a maladaptive expression of personality traits, which are relatively stable and unchanging. Thus, personality disorder has been considered to have its roots in childhood and adolescence, to persist in adulthood, and to be difficult to change. However, recent research has challenged this view, revealing that personality continues to change, albeit more slowly, well into adulthood, and that the maladaptive manifestations of personality disorder are much less stable than previously believed. These research findings are described, and factors that influence stability and change in personality disorder are discussed. The emerging view of personality disorder has important implications for diagnosis, assessment, and treatment of personality pathology.     

Stability and change in work values among male and female nurses and engineers

Gender related changes of work values were analyzed in a longitudinal questionnaire study of 173 male and 48 female engineers and 353 female and 31 male nurses at three measurement occasions covering about four and half years from the end of their vocational education. At all occasions, Social relations were rated as more important by women than by men and Altruism was given higher ratings by the nurses than by the engineers. Within both occupations women's mean Altruism ratings were higher than men's mean ratings, and in all groups except male engineers the mean ratings dropped between the three occasions. Women's ratings of Benefits and career and Influence were strengthened in both occupations, thereby eliminating an initial gender difference. The stability of work values is discussed in terms of challenges and norms in working life.