Experimental determination of trapping efficiency of optical tweezers

We report an experimental determination of trapping efficiency of optical fields acting on spherical particles diluted in viscous fluids. This parameter was derived from experimentally calculated trap stiffness for micron-sized silica beads with particle radii of 1.5 and 4.8 microns, respectively. In order to obtain the trap stiffness, we used the equipartition theorem, and introduced an experimental procedure to calibrate the optical tweezers set-up. The method consists of the calculation of the trapping efficiency by using the curves of the trap stiffness vs. the incident power. Using this approach we measured the efficiency for different values of displacements of the beads in the optical trap, and compared these results with numerical and theoretical calculations reported in the literature, and an excellent agreement was found. We have shown that the ratio of efficiencies is very close to the ratio of the particle radii.     

Economic cooperation in western Asia

Any changing system both develops and evolves (individuates). The evolution of the biosphere must therefore be taken in context of the development of the earth, which appears to have followed typical developmental rules of dissipative structures. Two different perspectives are possible on dissipative structures—the classical externalist perspective, which views open systems as becoming progressively negentropic, and the newer, internalist perspective, which views them from within as becoming increasingly disorderly. A history of the universe can be traced, alternately stressing the one and the other perspective, which can form the basic structure of a modern, science‐based creation myth.     

Kinetic study of static recrystallization in an Fe–Al–O ultra-fine-grained nanocomposite

A nearly abrupt coarsening of grains is observed in a newly developed Fe–Al–O ultra-fine-grained nanocomposite with a significant volume fraction (4%) of alumina nano-precipitates. The microstructure of the alloy was analysed in different states (as-received and annealed) by means of scanning electron microscopy, transmission electron microscopy (TEM) and hardness. The initial grain size 150–200 nm increases up to 50 μm during annealing 1000 °C/8 h and thereafter demonstrates saturation. A linear correlation between volume fraction of coarse grains and hardness was found. It was identified by TEM that alumina nano-precipitates stabilize the dislocation microstructure against recovery very effectively and the grain coarsening is due to fast growth of very few dislocation free grains. Thus, the observed grain coarsening has the attributes of static recrystallization.     

Teacher performance goal practices and elementary students' behavioral engagement: a developmental perspective

We investigated growth trajectories for classroom performance goal practices and for student behavioral engagement across grades 2 to 5 for 497 academically at-risk elementary students. This study is the first longitudinal investigation of performance goal practices in the early elementary years. On average, teacher use of performance goal practices increased and students' behavioral engagement declined across the four years. Using autoregressive latent trajectory (ALT) models, we examined the synchronous relations between teacher-reported performance goal practices and teacher-reported student behavioral engagement. As expected, as students move into classrooms with a new teacher with less emphasis on performance goal practices, they become more behaviorally engaged in school. Gender did not moderate these results. Implications for teacher professional development are discussed.     

‘Oh I do like to be beside the seaside’: opportunity structures for four un/underemployed young people living in English coastal towns

Long-term unemployed young people are a ‘social concern’ in many countries. The focus for research is usually cities, but may also include rural areas. The qualitative study described in this paper focuses instead on four young people living in coastal towns in South East England. The study suggests that their experiences in education and employment markets are shaped, negatively, by their particular location and the ongoing opportunity structures. The paper outlines their views and discusses the three main themes that emerged from the analysis: opportunity structures, supported resilience and the impact of living in a coastal town. Implications for targeted youth guidance are considered, alongside a consideration of the reflexive role of the researcher in such work.     

Reconceptualizing adult attachment relationships: A network perspective

This article explores attachment relationships from a network theory perspective: Correlations among behaviors, beliefs, and feelings related to attachment are hypothesized to stem from causal relations. The authors used two data sets that assessed relationships with four attachment figures (mother, father, romantic partner, and best friend) using the Relationship Structures Questionnaire. Separate networks (Gaussian Graphical Models) were estimated based on 10 items for each attachment figure. Across networks in Study 1 (N = 310), items related to anxiety, seeking support, and discomfort disclosing feelings clustered with other items from their respective domains; a trust‐related item bridged the clusters. Study 2 replicated these findings in a larger and more diverse sample (N = 3,710). The potential of network analysis for advancing the study of attachment is discussed.     

Facet-like Structures in Computer Science

This paper discusses how facet-like structures occur as a commonplace feature in a variety of computer science disciplines as a means for structuring class hierarchies. The paper then focuses on a mathematical model for facets (and class hierarchies in general), called formal concept analysis, and discusses graphical representations of faceted systems based on this model.

Logical Argument Structures in Decision-making

Perelman and Olbrechts-Tyteca's practical reasoning theory has attracted a great deal of interest since its publication in 1969. Their most important assertion, however, that argument is the logical basis for practical decision-making, has been under-utilized, primarily because it was not sufficiently operationalized for research purposes. This essay presents an operationalization of practical reasoning for use in analyzing argument logics that emerge through group interaction. Particular elements of discourse and argument are identified as responding to principles put forward by Perelman and Olbrechts-Tyteca, and are viewed as fitting together in a kind of logical argument structure that is well suited to the study of practical arguments in decision-making. Both the content elements and the logical argument structure are illustrated using examples from two studies examining decision logics in public participation and jury decision-making. Advantages of this approach and proposed recognition of a new `filtered' type of argument structure are discussed.     

AN ESSAY ON DREAMING,PSYCHICAL WORKING OUT AND WORKING THROUGH2

In this paper the author attempts to expand the idea put forward by Freud who considered dreams as a special form of unconscious thinking. It is the author's contention that the psychical working‐out function performed by dreams is a form of unconscious thinking, which transforms affects into memories and mental structures. He also attempts to clarify the way in which meaning is built and transformed in mental life. In that respect the unconscious internal world is seen as a form of unconscious thinking, a private theatre where meaning is generated and transformed. He focuses on what happens to feelings in dreams in connection with the meanings as a result of and an expression of the several stages of working through. The dream world is described as the setting where the mind gives expressive pictorial representation to the emotions involved in a conflict: a first step towards thinkability. The dreamwork also constitutes a process through which meaning is apprehended, built on and transformed at an expressive non‐discursive level, based on representation through figurative/pictorial images. The author draws on Meltzer's formulation to conjecture that the working‐through function of dreams, mainly in response to interpretations, is performed by a process of progression in formal qualities of the representations made available by dreaming in the form he has called affective pictograms. It is through progression in formal qualities of the representation that the thinking capabilities of the affective life develop and become part of the process of what is called metaphorically the metabolisation of emotional life. This process takes place through migration of meaning across various levels of mental process. In this perspective the analyst'sinterpretations of dreams effect what linguists call transmutation of the symbolic basis, a process that is necessary to help the mind to improve its capacity to think. Something expressed on the evocative plane and condensed into a pictographic image is then transformed into verbal language that expresses meaning. These conceptions are illustrated by a detailed clinical case.     

课堂环境目标影响学生成就目标的实验研究

采用现场教学实验的方法,探讨了在我国中学课堂教学中,运用TARGET教学模式引导学生的掌握目标定向,激发学习动机的有效性和可行性。被试是来自同一所中学的初中二年级两个班的学生(实验班36人,控制班34人)。研究结果表明,通过教师在课堂上实施强调掌握目标的教学干预策略,可以有效地改善学生的学习动机模式,促使学生更多地采取掌握目标,提高学生的学习兴趣和学习成绩。