Nanostructure and related mechanical properties of an Al–Mg–Si alloy processed by severe plastic deformation

Microstructural features and mechanical properties of an Al–Mg–Si alloy processed by high-pressure torsion (HPT) have been investigated using transmission electron microscopy, X-ray diffraction, three-dimensional atom probe, tensile tests and micro-hardness measurements. It is shown that HPT processing of the Al–Mg–Si alloy leads to a much stronger grain size refinement than of pure aluminium (down to 100 nm). Moreover, massive segregation of alloying elements along grain boundaries is observed. This nanostructure exhibits a yield stress even two times higher than that after a standard T6 heat treatment of the coarse-grained alloy.     

The Counseling Profession in Russia: Historical Roots,Current Trends,and Future Perspectives

Psychology was established in Russia before the Communist era. The social work profession was created in 1991 for a society in turmoil after the collapse of the Soviet Union. In 2011, the counseling profession officially emerged as a branch of social work called social psychological help. Professional counseling associations are in the formative stage. Concern about mental health issues, particularly substance abuse, suggests that the counseling profession could continue to grow in Russia.     

Dynamic balance between grain refinement and grain growth during high-pressure torsion of Cu powders

High-pressure torsion (HPT) was applied to unmilled coarse-grained (CG) Cu powders with low initial dislocation density and cryomilled nanocrystalline (nc) Cu powders with high initial dislocation density, with identical processing parameters. HPT of unmilled CG Cu powders resulted in exceptional grain refinement and increase in dislocation density, whereas significant grain growth and decrease in dislocation density occurred during HPT of cryomilled nc Cu powders. Equilibrium structures were achieved under both conditions, with very similar stable grain sizes and dislocation densities, suggesting dynamic balances between deformation-induced grain refinement and grain growth, and between deformation-induced dislocation accumulation and dislocation annihilation. The equilibrium structures are governed by these two dynamic balances.     

Working memory in social anxiety disorder: better manipulation of emotional versus neutral material in working memory

Individuals with social anxiety disorder (SAD) engage in post-event processing, a form of perseverative thinking. Given that deficits in working memory might underlie perseverative thinking, we examined working memory in SAD with a particular focus on the effects of stimulus valence. SAD (n?=?31) and healthy control (n?=?20) participants either maintained (forward trials) or reversed (backward trials) in working memory the order of four emotional or four neutral pictures, and we examined sorting costs, which reflect the extent to which performance deteriorated on the backward trials compared to the forward trials. Emotionality of stimuli affected performance of the two groups differently. Whereas control participants exhibited higher sorting costs for emotional stimuli compared to neutral stimuli, SAD participants exhibited the opposite pattern. Greater attention to emotional stimuli in SAD might facilitate the processing of emotional (vs. neutral) stimuli in working memory.     

Notes on Logics of Metric Spaces

In [14], we studied the computational behaviour of various first-order and modal languages interpreted in metric or weaker distance spaces. [13] gave an axiomatisation of an expressive and decidable metric logic. The main result of this paper is in showing that the technique of representing metric spaces by means of Kripke frames can be extended to cover the modal (hybrid) language that is expressively complete over metric spaces for the (undecidable) two-variable fragment of first-order logic with binary pred-icates interpreting the metric. The frame conditions needed correspond rather directly with a Boolean modal logic that is, again, of the same expressivity as the two-variable fragment. We use this representation to derive an axiomatisation of the modal hybrid variant of the two-variable fragment, discuss the compactness property in distance logics, and derive some results on (the failure of) interpolation in distance logics of various expressive power. Presented by Melvin Fitting     

The influence of aging on poststroke depression using a rat model via middle cerebral artery occlusion

Poststroke depression (PSD) is the most frequent psychological sequela following stroke. While previous studies describe the impact of age on brain infarct volume, brain edema, and blood–brain barrier (BBB) breakdown following ischemia, the role of age on PSD has yet to be described. Here, we examine the influence of age on PSD progression in a rat model of PSD by middle cerebral artery occlusion (MCAO). One hundred forty-three rats were divided into three groups. 48 rats 20 weeks of age underwent a sham procedure, 51 rats 20 weeks of age had MCAO, and 44 rats 22–26 months of age had MCAO. Groups were further divided into two subgroups. The first subgroup was used to measure infarct lesion volume, brain edema, and BBB breakdown at 24 h. In the second subgroup at 3 weeks after MCAO, rats were subjected to a sucrose preference test, two-way shuttle avoidance task, forced swimming test, and a brain-derived neurotrophic factor (BDNF) protein level measurement. Total and striatal infarct volume, brain edema, and BBB breakdown in the striatum were increased in older rats, as compared with younger rats. While both old and young rats exhibited depressive-like behaviors on each of the behavioral tests and lower BDNF levels post-MCAO, as compared with control rats, there were no differences between old and young rats. Although older rats suffered from larger infarct volumes, increased brain edema and more BBB disruption following MCAO, the lack of behavioral differences between young and old rats suggests that there was no effect of rat age on the incidence of PSD.     

High-strain induced reverse martensitic transformation in an ultrafine-grained Ti-Nb-Ta-Zr alloy

We report on a novel phenomenon, that is a high-strain-induced reverse martensitic transformation in an ultrafine-grained Ti–36Nb–2Ta–3Zr (wt.%) alloy processed by equal channel angular pressing (ECAP) at room temperature. Our results show that a martensitic transformation from body-centred cubic β matrix to orthorhombic α″ martensite occurs under low-strain ECAP conditions and that a large portion (~34%) of martensite transforms into a matrix phase (i.e. reverse martensitic transformation) with increasing ECAP strain to a high value of 4 (i.e. 6 passes) with a corresponding reduction in the α″-lath thickness and a refinement of grain size in the matrix phase.     

Contextual adjustments in cognitive control across tasks

Does encountering information-processing conflict recruit general mechanisms of cognitive control or change only the representations of specific cues and responses? In the present experiments, a flanker task elicited responses to symbolic information (arrow meaning), whereas Stroop-like tasks elicited responses to nonsymbolic information (color of a letter or location of a target box). Despite these differences, when participants performed the flanker and Stroop tasks intermittently in randomized orders, the extent of information-processing conflict encountered on a particular trial modulated performance on the following trial. On across-task trial pairs, increases in response time to incongruent relative to congruent stimulus arrays were smaller immediately following incongruent trials than immediately following congruent trials. The degree of cognitive control exerted on a particular task thus appears to reflect not only the quality, but also the quantity, of recent experiences of information-processing conflict.     

Punishment sensitivity and risk taking in depressed mood

Motivation and Emotion - Individuals with high levels of depressive symptoms find rewards to be less reinforcing and punishment more aversive, which may lead them to avoid risk taking. To examine...