Within- and between-subject consistency of perceptual segmentation in periodic noise: A combined behavioral tapping and EEG study

The human auditory system is capable of learning unstructured acoustic patterns that occur repeatedly. While most previous studies on perceptual learning focused on seamless pattern repetitions, our study included several presentation formats, which are more typical for memory tasks (involving temporal delays or irrelevant information between pattern presentations), and probed active recognition of learned patterns more directly. We adapted an established implicit learning paradigm and presented three groups of listeners with the same acoustic patterns in different presentation formats, i.e., either back-to-back, separated by a silent interval or by a masker sound. Participants additionally completed an unexpected memory test after the learning phase. We found substantial learning in all groups, measured indirectly via the increased sensitivity in a perceptual task for patterns that occurred repeatedly (compared to patterns that occurred only once) and more directly via above-chance recognition performance in the memory test. Pattern learning and recognition were robust across presentation formats. Therefore, we propose that similar mechanisms might underlie memory formation for initially unfamiliar sounds in everyday listening situations. Moreover, memories for unstructured acoustic patterns that were acquired implicitly through perceptual learning enable subsequent active recognition

Observation of Precipitation Evolution in Fe-Ni-Mn-Ti-Al Maraging Steel by Atom Probe Tomography

We describe the full decomposition sequence in an Fe-Ni-Mn-Ti-Al maraging steel during isothermal annealing at 550 °C. Following significant pre-precipitation clustering reactions within the supersaturated martensitic solid solution, (Ni,Fe)3Ti and (Ni,Fe)3(Al,Mn) precipitates eventually form after isothermal aging for ~60 seconds. The morphology of the (Ni,Fe)3Ti particles changes gradually during aging from predominantly plate-like to rod-like, and, importantly, Mn and Al were observed to segregate to these precipitate/matrix interfaces. The (Ni,Fe)3(Al,Mn) precipitates occurred at two main locations: uniformly within the matrix and at the periphery of the (Ni,Fe)3Ti particles. We relate this latter mode of precipitation to the Mn-Al segregation

Enhancement of Transition Temperature in FexSe0.5Te0.5 Film via Iron Vacancies

The effects of iron deficiency in FexSe0.5Te0.5 thin films (0.8<x<1) on superconductivity and electronic properties have been studied. A significant enhancement of the superconducting transition temperature (TC) up to 21K was observed in the most Fe deficient film (x=0.8). Based on the observed and simulated structural variation results, there is a high possibility that Fe vacancies can be formed in the FexSe0.5Te0.5 films. The enhancement of TC shows a strong relationship with the lattice strain effect induced by Fe vacancies. Importantly, the presence of Fe vacancies alters the charge carrier population by introducing electron charge carriers, with the Fe deficient film showing more metallic behavior than the defect-free film. Our study provides a means to enhance the superconductivity and tune the charge carriers via Fe vacancy, with no reliance on chemical doping.Comment: 15 pages, 4 figure

The genealogy of judgement: towards a deep history of academic freedom

The classical conception of academic freedom associated with Wilhelm von Humboldt and the rise of the modern university has a quite specific cultural foundation that centres on the controversial mental faculty of 'judgement'. This article traces the roots of 'judgement' back to the Protestant Reformation, through its heyday as the signature feature of German idealism, and to its gradual loss of salience as both a philosophical and a psychological concept. This trajectory has been accompanied by a general shrinking in the scope of academic freedom from the promulgation of world-views to the offering of expert opinion

Controlling the relaxation versus rejuvenation behavior in Zr-based bulk metallic glasses induced by elastostatic compression

Elastostatic compression (ESC) has received considerable research attention as a tool to study rejuvenation and relaxation processes for bulk metallic glasses (BMGs). However, little is understood about the conditions that control whether rejuvenation or relaxation will occur, and whether conditions exist that can give structural stability. We address these questions by applying ESC at 90% of the yield stress to both cast and laser powder bed fusion (LPBF) manufactured Zr-based BMG samples in the as-cast, as-built, and different annealed states. The structural state and mechanical properties for each material condition were characterized by differential scanning calorimetry and microhardness, respectively, and two representative groups were also used for compression testing. Initial relaxation or rejuvenation was observed for elastostatically compressed as-cast samples, and the behavior reversed over 72 h of ESC. In contrast, no ESC effect was observed for the as-built LPBF samples. It was found that the onset of either relaxation or rejuvenation by ESC could be better predicted if samples were annealed into a controlled initial state. Five different types of initial response to ESC were observed, corresponding to different initial energy state ranges. Materials in the highest and lowest initial energy states were stable against structural changes by ESC. Close to the highest energy state, rejuvenation was dominant, while relaxation took place close to the lowest energy state. At intermediate initial energy states, both relaxation and rejuvenation were observed after ESC loading, suggesting that the glass structure easily finds different local minima in the potential energy landscape. In all cases, relaxation was associated with BMG hardening and rejuvenation was associated with softening. Overall, the results of this study provide new insights into how ESC impacts the structural state and mechanical properties of BMGs