1,729 research outputs found
Explaining enhanced logical consistency during decision making in autism
The emotional responses elicited by the way options are framed often results in lack of logical consistency in human decision making. In this study, we investigated subjects with autism spectrum disorder (ASD) using a financial task in which the monetary prospects were presented as either loss or gain. We report both behavioral evidence that ASD subjects show a reduced susceptibility to the framing effect and psycho-physiological evidence that they fail to incorporate emotional context into the decision-making process. On this basis, we suggest that this insensitivity to contextual frame, although enhancing choice consistency in ASD, may also underpin core deficits in this disorder. These data highlight both benefits and costs arising from multiple decision processes in human cognition
Modulation of spatial attention to visual targets by emotional environmental sounds
Abstract Previous research has shown that visual spatial attention can be modulated by emotional prosody cues, but it is not known whether such crossmodal modulation of visual attention is associated with the engagement or disengagement of attentional resources. To test this, we employed a modified spatial cueing task, where participants indicated whether a visual target appeared either on the left or the right, after hearing a spatially non-predictive peripheral sound. Prior studies using prosody cues have found that modulation of visual attention by emotional auditory cues was lateralized, but this may have been due to the speech content of the stimuli; here instead we used non-speech environmental sounds. The sound was either emotional (pleasant, unpleasant) or neutral, and was presented either on the same side as the visual target ('valid' trial) or on the opposite side ('invalid' trial). For the cue validity index (RT to invalid cue minus RT to valid cue), we found differences between emotional and neutral cues, but only for visual targets presented in the right hemifield; here the cue validity index was lower for unpleasant compared to neutral and pleasant cues. Absolute RTs for targets on the right were faster for invalid trials following unpleasant cues, compared to pleasant and neutral cues, indicating that the reduced cue validity effect was due to faster disengagement from unpleasant auditory cues. Further, our results show that the laterality effect is related to the emotional nature of the cues, rather than the speech content of the stimuli
Selective Laser Melting of Nickel Superalloys: solidification, microstructure and material response
The Selective Laser Melting (SLM) process generates large thermal gradients during rapid melting, and during solidification certain nickel superalloys suffer from thermally induced micro-cracking which cannot be eliminated by process optimisation.
This investigation sought to investigate and understand the root cause of micro-cracking in nickel superalloys when processed by SLM, with the aim of ultimately being able to predict the crack susceptibility of an alloy from composition alone.
Microstructural analysis as well as implementation of Rapid Solidification Processing (RSP) theory and solute redistribution theory was used to establish SLM as a rapid solidification process. As a consequence, secondary dendrite arm formation and solute redistribution is largely inhibited, resulting in a bulk material which is near to a super saturated solid solution.
The establishment of SLM as an RSP along with morphological and chemical analysis of micro-cracks support Elevated Temperature Solid State (ETSS) cracking as the primary cracking mechanism in SLM processed nickel superalloys.
The crack susceptibility of a nickel superalloy, χ, was defined as the ratio between the solid solution strengthening contribution from alloying elements and apparent thermal stress generated by the process.
Minor increases in the wt% of solid solution strengthening elements in Hastelloy X, a high crack susceptibility alloy, resulted in average reductions of crack density of 65%. Thereby supporting solid solution strength as a key factor in the crack susceptibility of a nickel superalloy. The addition of the apparent thermal stress component, further supported the crack susceptibility model, with the modified Hastelloy X being predicted to have a lower crack susceptibility.
Additional validation of the crack susceptibility predictor was determined by taking compositions and material properties from published SLM investigations and calculating the crack susceptibility of the respective alloy. The results were found to be in good agreement with the reported observations
Selective Laser Melting of Nickel Superalloys: solidification, microstructure and material response
The Selective Laser Melting (SLM) process generates large thermal gradients during rapid melting, and during solidification certain nickel superalloys suffer from thermally induced micro-cracking which cannot be eliminated by process optimisation.
This investigation sought to investigate and understand the root cause of micro-cracking in nickel superalloys when processed by SLM, with the aim of ultimately being able to predict the crack susceptibility of an alloy from composition alone.
Microstructural analysis as well as implementation of Rapid Solidification Processing (RSP) theory and solute redistribution theory was used to establish SLM as a rapid solidification process. As a consequence, secondary dendrite arm formation and solute redistribution is largely inhibited, resulting in a bulk material which is near to a super saturated solid solution.
The establishment of SLM as an RSP along with morphological and chemical analysis of micro-cracks support Elevated Temperature Solid State (ETSS) cracking as the primary cracking mechanism in SLM processed nickel superalloys.
The crack susceptibility of a nickel superalloy, χ, was defined as the ratio between the solid solution strengthening contribution from alloying elements and apparent thermal stress generated by the process.
Minor increases in the wt% of solid solution strengthening elements in Hastelloy X, a high crack susceptibility alloy, resulted in average reductions of crack density of 65%. Thereby supporting solid solution strength as a key factor in the crack susceptibility of a nickel superalloy. The addition of the apparent thermal stress component, further supported the crack susceptibility model, with the modified Hastelloy X being predicted to have a lower crack susceptibility.
Additional validation of the crack susceptibility predictor was determined by taking compositions and material properties from published SLM investigations and calculating the crack susceptibility of the respective alloy. The results were found to be in good agreement with the reported observations
Extent of Fermi-surface reconstruction in the high-temperature superconductor HgBaCuO
High magnetic fields have revealed a surprisingly small Fermi-surface in
underdoped cuprates, possibly resulting from Fermi-surface reconstruction due
to an order parameter that breaks translational symmetry of the crystal
lattice. A crucial issue concerns the doping extent of this state and its
relationship to the principal pseudogap and superconducting phases. We employ
pulsed magnetic field measurements on the cuprate HgBaCuO to
identify signatures of Fermi surface reconstruction from a sign change of the
Hall effect and a peak in the temperature-dependent planar resistivity. We
trace the termination of Fermi-surface reconstruction to two hole
concentrations where the superconducting upper critical fields are found to be
enhanced. One of these points is associated with the pseudogap end-point near
optimal doping. These results connect the Fermi-surface reconstruction to both
superconductivity and the pseudogap phenomena.Comment: 5 pages. 3 Figures. PNAS (2020
Anisotropic determined up to 92 T and the signature of multi-band superconductivity in Ca(PtAs)((FePt)As) superconductor
The upper critical fields, (), of single crystals of the
superconductor
Ca(PtAs)((FePt)As)
( 0.246) are determined over a wide range of temperatures
down to = 1.42 K and magnetic fields of up to 92 T. The
measurements of anisotropic () curves are performed in pulsed
magnetic fields using radio-frequency contactless penetration depth
measurements for magnetic field applied both parallel and perpendicular to the
\textbf{ab}-plane. Whereas a clear upward curvature in
() along \textbf{H}\textbf{c} is
observed with decreasing temperature, the ()
along \textbf{H}\textbf{ab} shows a flattening at low temperatures.
The rapid increase of the () at low
temperatures suggests that the superconductivity can be described by two
dominating bands. The anisotropy parameter,
, is 7 close
to and decreases considerably to 1 with decreasing temperature,
showing rather weak anisotropy at low temperatures.Comment: 4pages, 3figures, accepted PRB Rapid Communicatio
The embodiment of emotional feelings in the brain
Central to Walter Cannon's challenge to peripheral theories of emotion was that bodily arousal responses are too undifferentiated to account for the wealth of emotional feelings. Despite considerable evidence to the contrary, this remains widely accepted and for nearly a century has left the issue of whether visceral afferent signals are essential for emotional experience unresolved. Here we combine functional magnetic resonance imaging and multiorgan physiological recording to dissect experience of two distinct disgust forms and their relationship to peripheral and central physiological activity. We show that experience of core and body–boundary–violation disgust are dissociable in both peripheral autonomic and central neural responses and also that emotional experience specific to anterior insular activity encodes these different underlying patterns of peripheral physiological responses. These findings demonstrate that organ-specific physiological responses differentiate emotional feeling states and support the hypothesis that central representations of organism physiological homeostasis constitute a critical aspect of the neural basis of feelings
Spin-flip and spin-conserving optical transitions of the nitrogen-vacancy centre in diamond
We map out the first excited state sublevel structure of single nitrogen-vacancy (NV) colour centres in diamond. The excited state is an orbital doublet where one branch supports an efficient cycling transition, while the other can simultaneously support fully allowed optical Raman spin-flip transitions. This is crucial for the success of many recently proposed quantum information applications of the NV defects. We further find that an external electric field can be used to completely control the optical properties of a single centre. Finally, a group theoretical model is developed that explains the observations and provides good physical understanding of the excited state structure
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