Exploration of atom probe tomography at sub-10K.

The operating temperature is a critical parameter in atom probe tomography experiments. It affects the spatial precision, mass resolving power and other key aspects of the field-evaporation process. Current commercially available atom probes operate at a minimum temperature of ∼25 K when measured at the specimen. In this paper, we explore and implement changes to the mechanical design of both the LEAPⓇ and EIKOS™ atom probe microscope systems manufactured by CAMECAⓇ to enable a specimen temperature in the sub-10 K regime. We use these modified instruments to analyze four materials systems: pure Al (in both pulsed-voltage and pulsed-laser mode), pure W (pulsed-voltage mode only), doped Si, and GaN (pulsed-laser mode only). The effects of conducting atom probe experiments in the sub-10 K regime were assessed with reference to a range of quantitative analysis metrics related to spatial precision, mass resolving power, stoichiometry and charge-state ratio. We demonstrate that the spatial precision is significantly improved with decreasing temperature, whilst the effect on mass resolving power is relatively minor. The enhanced spatial precision is significant insofar as it enables lattice planes from the doped Si samples to be resolved. Furthermore, mass spectral analysis, lower noise floors and changes in the field evaporation process enabled more accurate GaN compositional measurements. We discuss the significance of these findings for the semiconductor and metallurgical industries and the potential opportunities for further investigations of this parameter space.

Strong hearts, open minds: Cardiovascular challenge predicts non-defensive responses to ingroup-perpetrated violence.

Reminders of ingroup-perpetrated violence represent a psychological stressor that some people respond to defensively (e.g., justifying the violence), while others react non-defensively (e.g., accepting collective responsibility). To explain these divergent responses, we applied the biopsychosocial model of challenge and threat to the context of intergroup conflict. Participants (N = 130) read about either an ingroup (American) or outgroup (Australian) soldier torturing an Iranian captive. We recorded cardiovascular responses while participants video-recorded introductions to an Iranian confederate who they believed they would meet. In the ingroup (but not the outgroup) condition, cardiovascular responses of challenge (relative to threat) were associated with less psychological defensiveness of ingroup-perpetrated violence and greater support for diplomacy towards its victims. Self-reported challenge/threat appraisals demonstrated no such relationships. These findings suggest that motivational states of challenge and threat can differentiate defensive and non-defensive responses, and that these motivational states may be better captured with physiological rather than self-report measures.

Atom probe tomography (APT) of carbonate minerals.

Atom probe tomography (APT) combines the highest spatial resolution with chemical data at atomic scale for the analysis of materials. For geological specimens, the process of field evaporation and molecular ion formation and interpretation is not yet entirely understood. The objective of this study is to determine the best conditions for the preparation and analysis by APT of carbonate minerals, of great importance in the interpretation of geological processes, focusing on the bulk chemical composition. Results show that the complexity of the mass spectrum is different for calcite and dolomite and relates to dissimilarities in crystalochemical parameters. In addition, APT bulk chemistry of calcite closely matches the expected stoichiometry but fails to provide accurate atomic percentages for elements in dolomite under the experimental conditions evaluated in this work. For both calcite and dolomite, APT underestimates the amount of oxygen based on their chemical formula, whereas it is able to detect small percentages of elemental substitutions in crystal lattices. Overall, our results demonstrate that APT of carbonate minerals is possible, but further optimization of the experimental parameters are required to improve the use of atom probe tomography for the correct interpretation of mineral geochemistry.

On rivalry and goal pursuit: Shared competitive history, legacy concerns, and strategy selection.

Seven studies converge to show that prompting people to think about a rival versus a nonrival competitor causes them to view current competitions as more connected to past ones, to be more concerned with long-term legacy, and to pursue personal goals in a more eager, less cautious manner. These results are consistent with a social-cognitive view of rivalry that defines it as a competitive relational schema. A preliminary analysis revealed that people were more likely to appeal to past competitions to explain the importance of current rivalry than nonrivalry contests. Experiment 1 showed that people view rivalry versus nonrivalry competitions as more embedded in an ongoing competitive narrative and that this perception increases legacy concerns. The next 2 experiments used a causal chain approach to examine the possibility of legacy concerns acting as a mediator between rivalry and eagerness. Experiment 2a demonstrated that longer (vs. shorter) competitive histories are associated with increased legacy concerns. Experiment 2b manipulated legacy concerns and found that this shifted regulatory focus toward eagerness. Finally, 3 experiments tested the direct effect of thinking about a rival on eager strategy selection: Thinking about rivals (vs. nonrivals) led people to be more interested in offensive than defensive strategies (Experiment 3), to initiate rather than delay their goal pursuit (Experiment 4), and to rely on spontaneous rather than deliberative reasoning (Experiment 5). We suggest that rivalries affect how people view their goals and the strategies they use for pursuing them, and that these effects are at least partially attributable to the shared history between individuals and their rivals.

Social psychology. Just think: the challenges of the disengaged mind.

In 11 studies, we found that participants typically did not enjoy spending 6 to 15 minutes in a room by themselves with nothing to do but think, that they enjoyed doing mundane external activities much more, and that many preferred to administer electric shocks to themselves instead of being left alone with their thoughts. Most people seem to prefer to be doing something rather than nothing, even if that something is negative.

Expensive egos: narcissistic males have higher cortisol.

BACKGROUND: Narcissism is characterized by grandiosity, low empathy, and entitlement. There has been limited research regarding the hormonal correlates of narcissism, despite the potential health implications. This study examined the role of participant narcissism and sex on basal cortisol concentrations in an undergraduate population. METHODS AND FINDINGS: Participants were 106 undergraduate students (79 females, 27 males, mean age 20.1 years) from one Midwestern and one Southwestern American university. Narcissism was assessed using the Narcissistic Personality Inventory, and basal cortisol concentrations were collected from saliva samples in a laboratory setting. Regression analyses examined the effect of narcissism and sex on cortisol (log). There were no sex differences in basal cortisol, F(1,97) = .20, p = .65, and narcissism scores, F(1,97) = .00, p = .99. Stepwise linear regression models of sex and narcissism and their interaction predicting cortisol concentrations showed no main effects when including covariates, but a significant interaction, ß = .27, p = .04. Narcissism was not related to cortisol in females, but significantly predicted cortisol in males. Examining the effect of unhealthy versus healthy narcissism on cortisol found that unhealthy narcissism was marginally related to cortisol in females, ß = .27, p = .06, but significantly predicted higher basal cortisol in males, ß = .72, p = .01, even when controlling for potential confounds. No relationship was found between sex, narcissism, or their interaction on self-reported stress. CONCLUSIONS: Our findings suggest that the HPA axis is chronically activated in males with unhealthy narcissism. This constant activation of the HPA axis may have important health implications.