Study of a turbulent nitrogen-diluted hydrogen-air diffusion flame through large-eddy simulations coupled with a first order conditional moment closure method

this work concerns numerical simulations of a hydrogen diffusion flame, using Large Eddy Simulations (LES) and Conditional Moment Closure (CMC) as turbulent combustion model. In order to explore the effect of turbulence, two types of inlet boundary conditions are applied: White Noise and a method of Random Spots. The analysis of Favre-averaged profiles of velocity, mixture fraction, temperature and species has led to the conclusion that the method of Random Spots is in much better agreement with the experimental data, as expected. However, several discrepancies between simulations and experiments can also be caused by the boundary conditions applied at the sides and the outlet of the domain

Representing tools as hand movements: Early and somatotopic visuomotor transformations

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motor cortical inhibition during concurrent action execution and action observation

Abstract Action Execution (AE) and Action Observation (AO) share an extended cortical network of activated areas. During coordinative action these processes also overlap in time, potentially giving rise to behavioral interference effects. The neurophysiological mechanisms subtending the interaction between concurrent AE and AO are substantially unknown. To assess the effect of AO on observer's corticomotor drive, we run one electromyography (EMG) and three Transcranial Magnetic Stimulation (TMS) studies. Participants were requested to maintain a steady hand opening or closing posture while observing the same or a different action (hand opening and closing in the main TMS study). By measuring Cortical Silent Periods (CSP), an index of GABAB-mediated corticospinal inhibitory strength, we show a selective reduction of inhibitory motor drive for mismatching AE-AO pairs. The last two TMS experiments, show that this mismatch is computed according to a muscle-level agonist-antagonist representation. Combined, our results suggest that corticospinal inhibition may be the central neurophysiological mechanism by which one's own motor execution is adapted to the contextual visual cues provided by other's actions

L’origine comune di linguaggio e azione

Riassunto: Il sistema motorio presenta un’organizzazione particolarmente interessante per via delle sue forti analogie con il linguaggio. In questa sede, prendendo spunto dai alcuni studi di neurofisiologia, neuroanatomia e neuroimmagine funzionale, saranno tracciate le similarità più importanti tra l’organizzazione cerebrale del linguaggio e quelle dell’azione. Queste analogie saranno da sostegno per successive speculazioni riguardo ai meccanismi di evoluzione funzionale tra i due sistemi. In particolar modo, suggeriremo che le caratteristiche computazionali alla base del funzionamento del sistema motorio possano aver fornito gli elementi di base per l’emergere della sintassi e semantica nel linguaggio.Parole chiave: Sistema motorio; Gerarchia motoria; Ricorsività; Linguaggio; Azione.  The Shared Origin of Language and Action Abstract: Motor system organization shows some interesting parallels with language organization. Here we point out possible commonalities between Action and Language, basing our claims on neurophysiological, neuroanatomical and neuroimaging data. Furthermore, we speculate that the motor system may have furnished the basic computational capabilities for the emergence of both semantics and syntax.Keywords: Motoric System; Motoric Hierarchy; Recursivity; Language; Action

Interpersonal sensorimotor communication shapes intrapersonal coordination in a musical ensemble

Social behaviors rely on the coordination of multiple effectors within one's own body as well as between the interacting bodies. However, little is known about how coupling at the interpersonal level impacts coordination among body parts at the intrapersonal level, especially in ecological, complex, situations. Here, we perturbed interpersonal sensorimotor communication in violin players of an orchestra and investigated how this impacted musicians' intrapersonal movements coordination. More precisely, first section violinists were asked to turn their back to the conductor and to face the second section of violinists, who still faced the conductor. Motion capture of head and bow kinematics showed that altering the usual interpersonal coupling scheme increased intrapersonal coordination. Our perturbation also induced smaller yet more complex head movements, which spanned multiple, faster timescales that closely matched the metrical levels of the musical score. Importantly, perturbation differentially increased intrapersonal coordination across these timescales. We interpret this behavioral shift as a sensorimotor strategy that exploits periodical movements to effectively tune sensory processing in time and allows coping with the disruption in the interpersonal coupling scheme. As such, head movements, which are usually deemed to fulfill communicative functions, may possibly be adapted to help regulate own performance in time

The ART of Conversation: Measuring Phonetic Convergence and Deliberate Imitation in L2-Speech with a Siamese RNN

Phonetic convergence describes the automatic and unconscious speech adaptation of two interlocutors in a conversation. This paper proposes a Siamese recurrent neural network (RNN) architecture to measure the convergence of the holistic spectral characteristics of speech sounds in an L2-L2 interaction. We extend an alternating reading task (the ART) dataset by adding 20 native Slovak L2 English speakers. We train and test the Siamese RNN model to measure phonetic convergence of L2 English speech from three different native language groups: Italian (9 dyads), French (10 dyads) and Slovak (10 dyads). Our results indicate that the Siamese RNN model effectively captures the dynamics of phonetic convergence and the speaker's imitation ability. Moreover, this text-independent model is scalable and capable of handling L1-induced speaker variability.Comment: Accepted at INTERSPEECH 202

12 studying human human interaction to build the future of human robot interaction

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Multi-layer adaptation of group coordination in musical ensembles

Group coordination passes through an efficient integration of multimodal sources of information. This study examines complex non-verbal communication by recording movement kinematics from conductors and two sections of violinists of an orchestra adapting to a perturbation affecting their normal pattern of sensorimotor communication (rotation of half a turn of the first violinists\u2019 section). We show that different coordination signals are channeled through ancillary (head kinematics) and instrumental movements (bow kinematics). Each one of them affect coordination either at the inter-group or intra-group levels, therefore tapping into different modes of cooperation: complementary versus imitative coordination. Our study suggests that the co-regulation of group behavior is based on the exchange of information across several layers, each one of them tuned to carry specific coordinative signals. Multi-layer sensorimotor communication may be the key musicians and, more generally humans, use to flexibly communicate between each other in interactive sensorimotor tasks