Primary dendrite arm spacing during transient directional solidification of Al alloys with low redistribution coefficients

Particular analytical expressions based on a curve fitting on numerical results for primary dendritic growth have been proposed in the literature to encompass binary alloy systems whose redistribution coefficient (k ₀) approaches zero. To date, these expressions have not been checked against experimental results of transient solidification. The present study developed a comparative analysis between the theoretical predictions furnished by such expressions and results from transient solidification experiments with low k ₀ aluminum alloys. The analysis has shown that the proposed approach generally describes the primary dendritic spacing during solidification of Al–Sn alloys which are characterized by very low k ₀ values as well as by very large solidification ranges.     

Event centrality of positive and negative autobiographical memories to identity and life story across cultures

The aim of this study was to investigate whether cultural differences exist in event centrality, emotional distress and well-being in a total of 565 adults above age 40 from Mexico, Greenland, China and Denmark. Participants completed questionnaires to determine their level of post-traumatic stress disorder and depression symptoms, and of life satisfaction. They also completed event centrality scales for their most positive and most negative life events. Across cultures, participants rated positive events as more central to their identity and life stories, compared with negative events. Furthermore, participants with higher levels of emotional distress rated negative events as more central to their identity and life story, compared with participants with lower scores. However, a converse pattern was not found for positive events. Finally, participants with higher scores of life satisfaction tended to rate positive events as more central and negative events as less central to their identity and life story, compared with participants with lower scores. It is concluded that across cultures, positive events are considered more central to identity and life story than negative events and that event centrality ratings tend to be affected in similar ways by higher versus lower levels of emotional distress or well-being.     

Wittgenstein and Nonsense: Psychologism,Kantianism, and the Habitus

This paper is a critical examination of Wittgenstein's view of the limits of intelligibility. In it I criticize standard analytic readings of Wittgenstein as an advocate of transcendental or behaviourist theses in epistemology; and I propose an alternative interpretation of Wittgenstein's view as a social contextualism that transcends the false dichotomy between Kantianism and psychologism. I argue that this social contextualism is strikingly similar to the social account of epistemic practices developed by Pierre Bourdieu. Through a comparison between Wittgenstein's and Bourdieu's view and an analysis of the notion of habitus , I try to show how social contextualism can account for the distinction between sense and nonsense without falling into transcendental constructivism or social behaviourism.     

Student-Driven Courses on the Social and Ecological Responsibilities of Engineers

A group of engineering students at the Technical University of Berlin, Germany, designed a course on engineering ethics. The core element of the developed Blue Engineering course are self-contained teaching-units, “building blocks”. These building blocks typically cover one complex topic and make use of various teaching methods using moderators who lead discussions, rather than experts who lecture. Consequently, the students themselves started to offer the credited course to their fellow students who take an active role in further developing the course themselves.     

Diagnostic colours contribute to the early stages of scene categorization: Behavioural and neurophysiological evidence

We examined the effects of colour cues on the express categorization of natural scenes. Using a go/no-go paradigm sensitive to fast recognition processes, we measured early event-related potential (ERP) correlates of scene categorization to elucidate the processing stage at which colour contributes to scene recognition. Observers were presented with scenes belonging to four colour-diagnostic categories (desert, forest, canyon and coastline). Scenes were presented in one of three forms: Diagnostically coloured, nondiagnostically coloured, or greyscale images. In a verification task, observers were instructed to respond whenever the presented stimulus matched a previously presented category name. Reaction times and accuracy were optimal when the stimuli were presented as their original diagnostically coloured version, followed by their greyscale version, and lastly by their nondiagostically coloured version. These effects were mirrored in the early (i.e., 150 ms following stimulus onset) ERP frontal correlates. Their onset was delayed for greyscale scenes compared to diagnostically coloured scenes, and for nondiagnostically coloured scenes compared to the other two conditions. Frontal ERP amplitudes also decreased for greyscale and nondiagnostically coloured scenes. Together, the results suggest that diagnostic colours are part of the scene gist responsible for express scene categorization.     

Cognitive aging and flight performances in general aviation pilots

ABSTRACT

Unlike professional pilots who are limited by the FAA's age rule, no age limit is defined in general aviation. Our overall goal was to examine how age-related cognitive decline impacts piloting performance and weather-related decision-making. This study relied on three components: cognitive assessment (in particular executive functioning), pilot characteristics (age and flight experience), and flight performance. The results suggest that in comparison to chronological age, cognitive assessment is a better criterion to predict the flight performance, in particular because of the inter-individual variability of aging impact on cognitive abilities and the beneficial effect of flight experience.     

Dimensions of Job Satisfaction Identified Among South African Black Middle-level Managers: A Qualitative Investigation

The aim of the present study was to identify the factors contributing to job satisfaction for black middle-level managers and to contextualise these factors in terms of Afrocentric values and South Africa's socio-political and historical background. The sample comprised eight participants (4 males and 4 females), primarily from the educational sector, selected by means of purposive sampling. Semi-structured telephonic interviews were conducted to collect data, and the Interpretative Phenomenological Analysis (IPA) was used for in-depth analysis of the participants' experiences. Social needs consistent with Ubuntu were identified as important. These included a need for effective communication, transparency, trust and tolerance in the face of cultural and work-related differences. The frustrations associated with cultural differences and language barriers were elaborated on. For the participants, professional development and recognition were related to affirmative action policies and practices as well as the socio-political background. These findings contribute to the limited research available for the particular population—an essential contribution, given the cultural diversity of the South African workforce.     

First-time mothers’ experiences of meaningfulness during their third trimester of pregnancy: A focus on spirituality

This study sought to gain in-depth understanding of the lived experiences of first-time mothers during their third trimester of pregnancy. The non-probability, purposive sample were Afrikaans speaking first-time mothers aged between 22 and 40 years. Data on their experiences of meaningfulness during their pregnancy were collected using the Mmogo-Method® and reflective journals. The data were thematically analyzed combining textual data and visual depictions. This group of first-time mothers expressed a very personal relationship with a Divine reality that they rely on and derive meaningfulness from their pregnancy and birthing experiences. They perceived a Divine reality as the giver of life and that they were given a responsibility to carry new life. Sense of meaningfulness during pregnancy was strongly associated with spirituality.     

Index to Volume 129

This study addresses the basic structure of playfulness in adults from a psy-cho-lexical approach and its relationship with the sense of humor. Using items derived from a corpus analysis of written accounts in the German language, five factors were derived (N = 195); that is, (a) cheerful-engaged; (b) whimsical; (c) creative-loving; (d) intellectual; and (e) impulsive. Their contents strongly overlap in comparison with an earlier study using this approach. However, the correlation of the intellectual component with two current measures of adult playfulness was low, and the impulsive component was not correlated with these measures. The question arises as to whether these aspects exist only as components in the implicit psychological and linguistic theories. The sense of humor was most strongly related with the cheerful-engaged factor while some “humor skills” were particularly related to other factors; for example, finding humor under stress with the intellectual component. This study helps toward a better understanding of the basic structure of playfulness in adults.