Adverse conditions improve distinguishability of auditory, motor and perceptuo-motor theories of speech perception: an exploratory Bayesian modeling study

Special Issue: Speech Recognition in Adverse ConditionsInternational audienceIn this paper, we put forward a computational framework for the comparison between motor, auditory, and perceptuo-motor theories of speech communication. We first recall the basic arguments of these three sets of theories, either applied to speech perception or to speech production. Then we expose a unifying Bayesian model able to express each theory in a probabilistic way. Focusing on speech perception, we demonstrate that under two hypotheses, regarding communication noise and inter-speaker variability, providing perfect conditions for speech communication, motor, and auditory theories are indistinguishable. We then degrade successively each hypothesis to study the distinguish- ability of the different theories in ''adverse'' conditions. We first present simulations on a simplified implementation of the model with mono-dimensional sensory and motor variables, and secondly we consider a simulation of the human vocal tract providing more realistic auditory and articulatory variables. Simulation results allow us to emphasise the respective roles of motor and auditory knowledge in various conditions of speech perception in adverse conditions, and to suggest some guidelines for future studies aiming at assessing the role of motor knowledge in speech perception

Integrate, yes, but what and how? A computational approach of perceptuo-motor fusion in speech perception

International audienceWe consider a computational model comparing the possible roles of "association" and "simulation" in phonetic decoding, demonstrating that these two routes can contain similar information in some "perfect" communication situations and highlighting situations where their decoding performance differs. We conclude that optimal decoding should involve some sort of fusion of association and simulation in the human brain

Évaluation du stock de carbone et de la productivité en bois d'un parc à karités du Nord-Cameroun

In the sudanian zones of northern Cameroon, the steady influx of migrants is causing much land clearance in large swathes of savannah lands. Creating denser stands of relict tree populations would be of value at once for agronomic, economic and environmental reasons. A method for evaluating the carbon stored in aerial biomass is proposed here for a village area of shea trees (Vitellaria paradoxa). The aim is to introduce agroforestry projects that will be eligible for the Clean Development Mechanism (CDM) as from 2012. In addition, an evaluation of fuelwood productivity in the area, using pollarding methods, was conducted for about thirty trees over a three-year period. A series of allometric equations was developed (for six shea specimens and one specimen each of Anogeissus leiocarpus and Combretum nigricans), establishing a ratio between aerial biomass and the diameter of the trunk (at chest height or at the branch base) or the surface area of the crown. This provided an estimation of carbon stocks per tree, and then per plot. Given the human pressure exerted on the tree zone, it was established that an 8-year rotation between pollarding operations would offer a healthy trade-off between the various interests involved. These studies offer a preliminary approach that will need to be consolidated with hindsight. Keywords: Vitellaria paradoxa, Clean Development Mechanism (CDM), pollarding, fuelwood productivity, carbon, agroforestry, sudanian zone, Cameroon

F-actin mechanics control spindle centring in the mouse zygote

International audienceMitotic spindle position relies on interactions between astral microtubules nucleated by centrosomes and a rigid cortex. Some cells, such as mouse oocytes, do not possess centrosomes and astral microtubules. These cells rely only on actin and on a soft cortex to position their spindle off-centre and undergo asymmetric divisions. While the first mouse embryonic division also occurs in the absence of centrosomes, it is symmetric and not much is known on how the spindle is positioned at the exact cell centre. Using interdisciplinary approaches, we demonstrate that zygotic spindle positioning follows a three-step process: (1) coarse centring of pronuclei relying on the dynamics of an F-actin/Myosin-Vb meshwork; (2) fine centring of the metaphase plate depending on a high cortical tension; (3) passive maintenance at the cell centre. Altogether, we show that F-actin-dependent mechanics operate the switch between asymmetric to symmetric division required at the oocyte to embryo transition

The Application of X-Band Radar for Characterisation of Nearshore Dynamics on a Mixed Sand and Gravel Beach

Remote sensing using X-band radar allows the estimation of wave parameters, near surface currents and the underlying bathymetry. This paper explores the use of radar to derive nearshore bathymetry at a complex site, at Thorpeness in Suffolk, UK. The site has a history of sporadic and focused erosion events along the beach frontage and as part of the X-Com project (X-band Radar and Evidence-Based Coastal Management Decisions) a radar system was deployed with the aim of further understanding the complex nearshore sediment processes influencing erosion. Initially, the bathymetric variation at the site is quantified through analysis of current and historic multibeam surveys. These indicate depth changes approaching 3 m. Subsequently, validation of the radar data against concurrent multibeam survey data has been undertaken. Results show that the radar derived bathymetry has a precision of ±1m at the site, with the largest errors being associated with areas of more complex bathymetry and where wave data quality was less suitable for analysis by the X-band radar bathymetry algorithms. It is concluded that although the accuracy of radar-derived bathymetry is lower than traditional multibeam survey, the low cost for high temporal coverage can be utilised for long-term monitoring of coastal sites where a cost-effective means of quantifying large-scale bathymetric changes is required

Microstructure and mechanical properties of high strength steel deposits obtained by Wire-Arc Additive Manufacturing

Wire-arc additive manufacturing has become an alternative way to produce industrial parts. In this work 15 kg walls are built with an effective building rate of 4.85 kg/h using an ER100 wire providing good tensile properties and toughness under welding conditions. The thermal evolution of the walls during manufacturing is measured by thermocouples and an IR camera: it depends on process parameters, deposit strategy and the size of the part. The walls are then characterised as deposit and after heat treatment through hardness, tensile and Charpy-V notch tests. The results show a fine microstructure with unexpected retained austenite and coarse allotriomorphic ferrite in the as deposited walls. The final hardness values vary from about 220 to 280 HV2; the yield stress and tensile strength are 520 and 790 MPa, respectively, and a toughness of about 50 J is obtained at room temperature. The heat treatment transforms the retained austenite, leading to an improvement of the yield stress to 600 MPa

Prospective study on a fast-track training in psychiatry for medical students: the psychiatric hat game

Abstract: Background: While medical students are losing interest in lectures in favor of other educational materials, many studies suggest the benefit of active learning, combined with gamified educational tools. The authors developed a psychiatric adaptation of the « Hat Game ». It was hypothesised that this game would increase both knowledge and motivation in medical students toward psychiatric semiology. The aim of the study was to assess the benefit of a Psychiatric Hat Game session for learning psychiatric symptoms in third-year medical students. Student performance was also evaluated at 3 months. Methods: This gamified fast-track training consists of two teams and each team has to guess as many psychiatric semiology terms as possible using different techniques (i.e. speech, mime). The study involved a pre- and post-evaluation of knowledge (Multiple Choice Questions) and a satisfaction survey. Baseline, post-immediate, and three-months scores were compared by using Friedman analysis for paired samples. Comparisons of mean scores at two different times were performed by using Wilcoxon test for paired samples. Results: One hundred and sixty-six students were proposed to take part in the study. Among them 129 completed the whole program (response rate = 77.7%). Mean scores measured at the three points in time were significantly different (p < 0.001, N = 129). Knowledge mean scores were significantly higher after the game than before (+ 28.6%, p < 0.001). Improvement was maintained 3 months after the game (+ 18.9%, p < 0.001). Satisfaction survey items highlighted that students enjoyed and would recommend this type of gamified training. Conclusions: The Psychiatric Hat Game improved knowledge of psychiatric semiology in medical students. Results suggest that it is a promising and efficient tool to playfully teach medical semiology, with transferable features, utility and acceptability from one medical field to another. This study contributes to the growing body of knowledge advocating for serious games and gamified training in medical education.Version of Recor

Shape Self-Regulation in Early Lung Morphogenesis

The arborescent architecture of mammalian conductive airways results from the repeated branching of lung endoderm into surrounding mesoderm. Subsequent lung’s striking geometrical features have long raised the question of developmental mechanisms involved in morphogenesis. Many molecular actors have been identified, and several studies demonstrated the central role of Fgf10 and Shh in growth and branching. However, the actual branching mechanism and the way branching events are organized at the organ scale to achieve a self-avoiding tree remain to be understood through a model compatible with evidenced signaling. In this paper we show that the mere diffusion of FGF10 from distal mesenchyme involves differential epithelial proliferation that spontaneously leads to branching. Modeling FGF10 diffusion from sub-mesothelial mesenchyme where Fgf10 is known to be expressed and computing epithelial and mesenchymal growth in a coupled manner, we found that the resulting laplacian dynamics precisely accounts for the patterning of FGF10-induced genes, and that it spontaneously involves differential proliferation leading to a self-avoiding and space-filling tree, through mechanisms that we detail. The tree’s fine morphological features depend on the epithelial growth response to FGF10, underlain by the lung’s complex regulatory network. Notably, our results suggest that no branching information has to be encoded and that no master routine is required to organize branching events at the organ scale. Despite its simplicity, this model identifies key mechanisms of lung development, from branching to organ-scale organization, and could prove relevant to the development of other branched organs relying on similar pathways

Pre-mission InSights on the Interior of Mars

Abstract The Interior exploration using Seismic Investigations, Geodesy, and Heat Trans- port (InSight) Mission will focus on Mars’ interior structure and evolution. The basic structure of crust, mantle, and core form soon after accretion. Understanding the early differentiation process on Mars and how it relates to bulk composition is key to improving our understanding of this process on rocky bodies in our solar system, as well as in other solar systems. Current knowledge of differentiation derives largely from the layers observed via seismology on the Moon. However, the Moon’s much smaller diameter make it a poor analog with respect to interior pressure and phase changes. In this paper we review the current knowledge of the thickness of the crust, the diameter and state of the core, seismic attenuation, heat flow, and interior composition. InSight will conduct the first seismic and heat flow measurements of Mars, as well as more precise geodesy. These data reduce uncertainty in crustal thickness, core size and state, heat flow, seismic activity and meteorite impact rates by a factor of 3–10× relative to previous estimates. Based on modeling of seismic wave propagation, we can further constrain interior temperature, composition, and the location of phase changes. By combining heat flow and a well constrained value of crustal thickness, we can estimate the distribution of heat producing elements between the crust and mantle. All of these quantities are key inputs to models of interior convection and thermal evolution that predict the processes that control subsurface temperature, rates of volcanism, plume distribution and stability, and convective state. Collectively these factors offer strong controls on the overall evolution of the geology and habitability of Mars