Dynamic properties of an ultrafine-grained Mg–Zn–Zr alloy

The effect of ultrafine-grained structure formation in Mg–Zn–Zr alloy ZK60 on its mechanical response was investigated at strain rates ranging from quasi-static to dynamic regimes. The study demonstrated that the strength characteristics of the material rise significantly with increasing strain rate, while its ductility is reduced. These effects are particularly pronounced in the dynamic loading regime, at strain rates in the (1?5)?×?10²?s^?1 range. In the ultrafine-grained alloy ZK60, the energy absorption per unit volume, W, is enhanced by grain refinement by a factor as high as eight for the highest strain rate of 5?×?10²?s^?1 investigated. The analysis is focused on the microstructure features that bring about the observed improvement of the tensile characteristics, as well as the deformation and fracture modes prevalent at different strain rates. The results obtained contribute to the exploration and understanding of dynamic behaviour of magnesium alloys.     

Implicit interpretation biases affect emotional vulnerability: A training study

Cognitive theories of emotion propose that the interpretation of emotion-eliciting situations crucially shapes affective responses. Implicit or automatic biases in these interpretations may hinder emotion regulation and thereby increase risk for the onset and maintenance of psychological disorders. In this study, participants were randomly assigned to a positive or negative interpretation bias training using ambiguous social scenarios. After the completion of the training, a stress task was administered and changes in positive and negative affect and self-esteem were assessed. The results demonstrate that the interpretation bias training was successful in that participants exhibited a tendency to interpret novel scenarios in accordance with their training condition. Importantly, the positive training condition also had a protective effect on self-esteem. Participants in this condition did not exhibit a decrease in self-esteem after the stress task, whereas participants in the negative condition did. These results demonstrate that implicit cognitive biases can be trained and that this training affects self-esteem. Implications of these findings for research on psychopathology and emotion regulation are discussed.     

Redesigning work through idiosyncratic deals

This study links idiosyncratic deals (i-deals) to job design theory. It investigates the impact of individually negotiated job changes on performance, self-efficacy, and psychological strain through their intervening effects on work design. Based on a sample of 187 health care professionals employed by a hospital in Germany, three types of work design-related i-deals were investigated: (1) task, (2) career, and (3) flexibility i-deals. Consistent with hypotheses, the three types of i-deal had differential effects on work characteristics, and each in turn related to different outcomes. Specifically, job autonomy mediated the task i-deals—job performance relationship; skill acquisition mediated the career i-deals—occupational self-efficacy relationship; and reduced work overload mediated the flexibility i-deals—emotional and affective irritation relationships. Leader–Member Exchange was confirmed as an antecedent of all three types of i-deals. Task, career, and flexibility i-deals are discussed as ways to make work more intrinsically motivating, ensure one’s professional advancement, and balance workplace stressors.     

Beyond judgment bias: How students’ ethnicity and academic profile consistency influence teachers’ tracking judgments

Research on school tracking has provided evidence that students with immigrant backgrounds are overrepresented in the lower school tracks. As teachers are the main decision makers when it comes to tracking, we investigated whether teachers’ tracking judgments are biased by the immigrant backgrounds of the students and how teachers’ tracking judgments are affected by inconsistencies in students’ academic profiles. Drawing on dual process models of judgment formation, we conducted two experimental studies to investigate teachers’ judgments. The results of both studies showed less favorable teacher judgments of students with immigrant backgrounds than of students without immigrant backgrounds. Students with inconsistent academic profiles were also judged less favorably than students with consistent profiles. Think aloud data indicated careful processing of all information both for students with immigrant backgrounds and students with inconsistent profiles. Results are discussed with regard to their underlying mechanisms as well as with regard to their implications for teacher training.     

Hilbert's Programs and Beyond

Pour résoudre les paradoxes bien connus de la mécanique quantique, on propose une interprétation par ramification (ou univers parallèles) analogue à celle d’Everett, mais avec des différences: (i) on propose une infinité continue de branches, dont les poids (o[ugrave] probabilités) se calculent par intégrale; (ii) les branches sont séparées par des ramifieurs qui se propagent à la vitesse de la lumière. Lorsqu’est négligeable la composante d’énergie négative de la fonction d’onde, le poids de chaque branche en un point donné u est égal au flux du quadrivecteur (courant-densité de présence), soit à travers l'élément d’écran antérieur à u sur lequel l'impact est perçu, soit à travers le cône passé de u si aucun impact n’est perçu.

In order to solve well-known paradoxes in quantum mechanics, we propose a reworking of Everett's interpretation with ramified branches (or many worlds), yet somewhat different: (i) branches form an infinity continuum and each weight (probability) is defined by an integral; (ii) branches are separated by ramifiers which propagate themselves with the velocity of light. Assuming we can neglect the negative-energy component in the wave function, then the weight of each branch at a given point u is equal to the flux of the quadrivector (current-presence density), either through the screen element where the impact occurs, or through the past light-cone of u if no impact occurs.     

‘Metamathematics’ in Transition

In this paper, we trace the conceptual history of the term ‘metamathematics’ in the nineteenth century. It is well known that Hilbert introduced the term for his proof-theoretic enterprise in about 1922. But he was verifiably inspired by an earlier usage of the phrase in the 1870s. After outlining Hilbert's understanding of the term, we will explore the lines of inducement and elucidate the different meanings of ‘metamathematics’ in the final decades of the nineteenth century. Finally, we will investigate the earlier occurrences and come to the conclusion that the conceptual prehistory of the Hilbertian notion of metamathematics dates back to 1870, whereas the history of the word starts in 1799 at the latest.

What is this: metamathematics? It is something amazing everybody, […] since it makes the mind dizzy and withdraws thinking its sole fulcrum.1 ¹ Brunner 1898, p. 832: ‘Was ist das: Metamathematik? Es ist etwas, was einen Jeden in das äusserste Staunen versetzt, […] was das Gehirn schwindlig macht und dem Denken seinen einzigen Stütz- und Angelpunkt zu entziehen droht’.      

Emotional expression affects the accuracy of gaze perception

Emotional facial expressions are powerful social cues. Here we investigated how emotional expression affects the interpretation of eye gaze direction. Fifty-two observers judged where faces were looking by moving a slider on a measuring bar to the respective position. The faces displayed either an angry, happy, fearful or a neutral expression and were looking either straight at the observer, or were rotated 2°, 4°, 6° or 8° to the left and right. We found that happy faces were interpreted as directed closer to the observer, while fearful and angry faces were interpreted as directed further away. Judgments were most accurate for neutral faces, followed by happy, angry and fearful faces. These findings are discussed on the background of the “self-referential positivity bias”, suggesting that happy faces are preferably interpreted as directed towards the self while negative emotions are interpreted as directed further away.