Notes sur les phlébotomes de l'Aïr (Niger)

238 phlébotomes appartenant à 7 espèces ont été récoltés dans 4 stations du massif de l'Aïr au Niger. #Phlebotomus bergeroti était l'espèce dominante sur appât animal (âne) et dans les récoltes domiciliaires. Une attention spéciale est portée à #P. alexandri, vecteur de kala-azar dans d'autres foyers. (Résumé d'auteur

Effects of the relative timing of opposite-polarity pulses on loudness for cochlear implant listeners.

The symmetric biphasic pulses used in contemporary cochlear implants (CIs) consist of both cathodic and anodic currents, which may stimulate different sites on spiral ganglion neurons and, potentially, interact with each other. The effect on the order of anodic and cathodic stimulation on loudness at short inter-pulse intervals (IPIs; 0-800 μs) is investigated. Pairs of opposite-polarity pseudomonophasic (PS) pulses were used and the amplitude of each pulse was manipulated independently. In experiment 1 the two PS pulses differed in their current level in order to elicit the same loudness when presented separately. Six users of the Advanced Bionics CI (Valencia, CA) loudness-ranked trains of the pulse pairs using a midpoint-comparison procedure. Stimuli with anodic-leading polarity were louder than those with cathodic-leading polarity for IPIs shorter than 400 μs. This effect was small-about 0.3 dB-but consistent across listeners. When the same procedure was repeated with both PS pulses having the same current level (experiment 2), anodic-leading stimuli were still louder than cathodic-leading stimuli at very short intervals. However, when using symmetric biphasic pulses (experiment 3) the effect disappeared at short intervals and reversed at long intervals. Possible peripheral sources of such polarity interactions are discussed

Caractéristiques sociosémantiques des méthodes conventionnelles et alternatives de délibération

Cette recherche vise à caractériser les catégories de méthodes de délibération (l’une conventionnelle et l’autre alternative) selon le réseau social et la similarité des discours entre les personnes. Dans le cadre d’un mini-public délibératif réunissant 95 personnes, les centralités de degré, d’intermédiarité et de proximité dans le réseau social et leur centralité dans le réseau sociosémantique ont été mesurées. Les résultats indiquent que les centralités sociale et sociosémantique sont liées. La méthode conventionnelle favorise l’émergence du lien entre la centralité sociale et la centralité sociosémantique, tandis que la méthode alternative favorise l’émergence d’un lien négatif entre ces mesures. Ainsi, en mode conventionnel, cela semble favoriser l’émergence de convergences formulées par les personnes centrales, alors qu’en mode alternatif l’émergence des divergences serait un espace pour l’expression d’un discours distinct de celui des personnes centrales.This research aims to characterize types of deliberation method (conventional and alternative) by the similarity of speech in relation with the social network. A total of 95 people were gathered for an experiment where we measured their degree of centrality, betweenness and closeness in the social network, and their centrality in the sociosemantic network. Results indicate that measures of social centralities and sociosemantic centrality are related during the experiment. Specifically, the conventional deliberation method fosters the emergence of the link between social centrality and sociosemantic centrality, while the alternative method led to the emergence of a negative relationship between these measures. Thus, the conventional deliberation setting seems to favor the emergence of convergence around what central people are saying while the alternative setting appears to support the expression of a different speech

Large Deviations Analysis for Distributed Algorithms in an Ergodic Markovian Environment

We provide a large deviations analysis of deadlock phenomena occurring in distributed systems sharing common resources. In our model transition probabilities of resource allocation and deallocation are time and space dependent. The process is driven by an ergodic Markov chain and is reflected on the boundary of the d-dimensional cube. In the large resource limit, we prove Freidlin-Wentzell estimates, we study the asymptotic of the deadlock time and we show that the quasi-potential is a viscosity solution of a Hamilton-Jacobi equation with a Neumann boundary condition. We give a complete analysis of the colliding 2-stacks problem and show an example where the system has a stable attractor which is a limit cycle

The theory of quantum levitators

We develop a unified theory for clocks and gravimeters using the interferences of multiple atomic waves put in levitation by traveling light pulses. Inspired by optical methods, we exhibit a propagation invariant, which enables to derive analytically the wave function of the sample scattering on the light pulse sequence. A complete characterization of the device sensitivity with respect to frequency or to acceleration measurements is obtained. These results agree with previous numerical simulations and confirm the conjecture of sensitivity improvement through multiple atomic wave interferences. A realistic experimental implementation for such clock architecture is discussed.Comment: 11 pages, 6 Figures. Minor typos corrected. Final versio

Bayesian model comparison in cosmology with Population Monte Carlo

We use Bayesian model selection techniques to test extensions of the standard flat LambdaCDM paradigm. Dark-energy and curvature scenarios, and primordial perturbation models are considered. To that end, we calculate the Bayesian evidence in favour of each model using Population Monte Carlo (PMC), a new adaptive sampling technique which was recently applied in a cosmological context. The Bayesian evidence is immediately available from the PMC sample used for parameter estimation without further computational effort, and it comes with an associated error evaluation. Besides, it provides an unbiased estimator of the evidence after any fixed number of iterations and it is naturally parallelizable, in contrast with MCMC and nested sampling methods. By comparison with analytical predictions for simulated data, we show that our results obtained with PMC are reliable and robust. The variability in the evidence evaluation and the stability for various cases are estimated both from simulations and from data. For the cases we consider, the log-evidence is calculated with a precision of better than 0.08. Using a combined set of recent CMB, SNIa and BAO data, we find inconclusive evidence between flat LambdaCDM and simple dark-energy models. A curved Universe is moderately to strongly disfavoured with respect to a flat cosmology. Using physically well-motivated priors within the slow-roll approximation of inflation, we find a weak preference for a running spectral index. A Harrison-Zel'dovich spectrum is weakly disfavoured. With the current data, tensor modes are not detected; the large prior volume on the tensor-to-scalar ratio r results in moderate evidence in favour of r=0. [Abridged]Comment: 11 pages, 6 figures. Matches version accepted for publication by MNRA

Practical Considerations when Using the Swedish Fall Cone

This paper presents the results of Swedish fall cone tests and Casagrande liquid limit tests conducted on saline Champlain Sea clay samples from Lachenaie, Quebec. The main objective was to study a few hitherto unanswered practical questions regarding these testing methods. Penetration range is found to affect the Hansbo’s relationship used in fall cone experiments, while the mass and the bluntness degree of the cone have no effect on it. A direct relationship between thixotropic regain in shear strength and sensitivity is found. When measuring the liquid limit, if only the first penetration depth is recorded, results are up to 5% smaller than those obtained when following the standard procedure of CAN/BNQ-2501-092. With this standard, the average of the first two penetration depths within 0.3 mm of each other is recorded. These penetrations usually follow the bulk of the thixotropic shear strength regain. The Swedish fall cone was compared to the traditional Casagrande apparatus for liquid limit determinations. The two methods yielded identical results in the studied conditions (saline Lachenaie clay with liquid limit between 44% and 75%). An incorrect calibration of the height-of-drop of 1.4 mm led to a mean error of 6 liquid limit points. This error is greater than the theoretical error obtained by assuming that the number of blows is proportional to the square of the height-of-drop

Characterizing flows with an instrumented particle measuring Lagrangian accelerations

We present in this article a novel Lagrangian measurement technique: an instrumented particle which continuously transmits the force/acceleration acting on it as it is advected in a flow. We develop signal processing methods to extract information on the flow from the acceleration signal transmitted by the particle. Notably, we are able to characterize the force acting on the particle and to identify the presence of a permanent large-scale vortex structure. Our technique provides a fast, robust and efficient tool to characterize flows, and it is particularly suited to obtain Lagrangian statistics along long trajectories or in cases where optical measurement techniques are not or hardly applicable.Comment: submitted to New Journal of Physic