487 research outputs found
Hippocampal sclerosis affects fMR-adaptation of lyrics and melodies in songs
Songs constitute a natural combination of lyrics and melodies, but it is unclear whether and how these two song components are integrated during the emergence of a memory trace. Network theories of memory suggest a prominent role of the hippocampus, together with unimodal sensory areas, in the build-up of conjunctive representations. The present study tested the modulatory influence of the hippocampus on neural adaptation to songs in lateral temporal areas. Patients with unilateral hippocampal sclerosis and healthy matched controls were presented with blocks of short songs in which lyrics and/or melodies were varied or repeated in a crossed factorial design. Neural adaptation effects were taken as correlates of incidental emergent memory traces. We hypothesized that hippocampal lesions, particularly in the left hemisphere, would weaken adaptation effects, especially the integration of lyrics and melodies. Results revealed that lateral temporal lobe regions showed weaker adaptation to repeated lyrics as well as a reduced interaction of the adaptation effects for lyrics and melodies in patients with left hippocampal sclerosis. This suggests a deficient build-up of a sensory memory trace for lyrics and a reduced integration of lyrics with melodies, compared to healthy controls. Patients with right hippocampal sclerosis showed a similar profile of results although the effects did not reach significance in this population. We highlight the finding that the integrated representation of lyrics and melodies typically shown in healthy participants is likely tied to the integrity of the left medial temporal lobe. This novel finding provides the first neuroimaging evidence for the role of the hippocampus during repetitive exposure to lyrics and melodies and their integration into a song
The Interaction of High-Speed Turbulence with Flames: Global Properties and Internal Flame Structure
We study the dynamics and properties of a turbulent flame, formed in the
presence of subsonic, high-speed, homogeneous, isotropic Kolmogorov-type
turbulence in an unconfined system. Direct numerical simulations are performed
with Athena-RFX, a massively parallel, fully compressible, high-order,
dimensionally unsplit, reactive-flow code. A simplified reaction-diffusion
model represents a stoichiometric H2-air mixture. The system being modeled
represents turbulent combustion with the Damkohler number Da = 0.05 and with
the turbulent velocity at the energy injection scale 30 times larger than the
laminar flame speed. The simulations show that flame interaction with
high-speed turbulence forms a steadily propagating turbulent flame with a flame
brush width approximately twice the energy injection scale and a speed four
times the laminar flame speed. A method for reconstructing the internal flame
structure is described and used to show that the turbulent flame consists of
tightly folded flamelets. The reaction zone structure of these is virtually
identical to that of the planar laminar flame, while the preheat zone is
broadened by approximately a factor of two. Consequently, the system evolution
represents turbulent combustion in the thin-reaction zone regime. The turbulent
cascade fails to penetrate the internal flame structure, and thus the action of
small-scale turbulence is suppressed throughout most of the flame. Finally, our
results suggest that for stoichiometric H2-air mixtures, any substantial flame
broadening by the action of turbulence cannot be expected in all subsonic
regimes.Comment: 30 pages, 9 figures; published in Combustion and Flam
Microdosing psychedelics:Does it have an impact on emodiversity?
Background and aims Previous research has proposed that microdosing, i.e., the repeated use of sub-threshold doses of serotonergic hallucinogens, has an impact on mood by increasing emotional awareness. We propose that increased emotional awareness could translate into higher emodiversity, a balanced experience of emotions in which emotions are experienced with more similarity in intensity and duration. We examine the effect of microdosing, the day after, as well as the cumulative effect of microdosing on overall, positive and negative emodiversity. Methods We use data collected over a period of 28 days sampled between February to June 2020 from 18 users that already had an active practice of microdosing at the start of the data collection. We assessed emotional states using ESM methods, i.e., signal-contingent sampling with triggers sent 5 times a day. The working dataset has a number of 224 observations days. We used mixed effects models to test our hypotheses. Results When taking into account the level of average affect, we found that during microdosing days positive and overall emodiversity were significantly lower. No evidence was found for a mediating role of the level of average affect. Higher cumulative instances of microdosing were not related to any of the emodiversity indexes. Participants experienced more “awe, wonder, or amazement”, “ashamed, humiliated, or disgraced” as well as less “joyful, glad, or happy” emotions during microdosing days. Conclusion A microdosing practice may increase the centrality of certain emotions on microdosing days, resulting in a decrease in emotional diversity
Onset of fluidization in vertically shaken granular material
When granular material is shaken vertically one observes convection, surface
fluidization, spontaneous heap formation and other effects. There is a
controversial discussion in literature whether there exists a threshold for the
Froude number below which these effects cannot be
observed anymore. By means of theoretical analysis and computer simulation we
find that there is no such single threshold. Instead we propose a modified
criterion which coincides with critical Froude number for small
driving frequency .Comment: 7 pages, 5 figure
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